Moparchat - Home of MOPAR enthusiasts worldwide!



Go Back   Moparchat - Home of MOPAR enthusiasts worldwide! > Technical Forums > Jeep Chat (Wrangler, Cherokee, etc...)

Click here to search for Mopar cars and parts for sale.


Reply
 
Thread Tools Display Modes
  #1  
Old 09-01-1999, 05:44 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Question

Hi all!

I have a couple of questions regarding the older throttle body fuel injection used on the Pre-Magnum engines.

I have a 1990 D150 with the 3.9L V-6, 5 spd, and 3.9 rear gears. As you can imagine, it's a performance slug!

However, I have an opportunity to get a supercharger from a Ford SuperCoupe, that has the 3.8L V-6. I figure the supercharger should be pretty well suited to the engine
displacement, and I've got plenty of room under the hood for creating custom mounting bracketry to physically install the supercharger.

The question I have is this. Will a supercharger work with the trucks fuel injection/computer? I'm installing
a JET Stage II computer to allow better ignition timing and increased fuel supply so that I won't run lean. And I'm also going to install other components that were recommended by JET for use with their chip, such as a lower temperature thermostat, low restriction air filter, and a few other
items. According to JET, as far as their chip is concerned, it can handle supercharging as long as boost is kept at
no more than 5 psi.

I've contacted Holley and asked them, since they manufactured the throttle body, and they said that as far as the throttle body itself goes, it can handle supercharging, but they
don't know anything about the OEM computer.

I've contacted the Mopar Performance "Tech Line". Complete waste of time and effort. I'll never contact them again.

I guess I'm just wondering if anyone else has been able to use a supercharger successfully with the older throttle body fuel injection and factory computer, and if you have any advice, insight, or tips on how I can do this.

Thanks in advance for any help you can offer.
Regards,
400Magnum
Reply With Quote
  #2  
Old 09-02-1999, 12:46 AM
Christopher's Avatar
Christopher Christopher is offline
Inactive User
 
Join Date: Mar 1999
Location: fl
Posts: 2,018
Cool

The "problem" with the factory computer is that it is a "speed density" system. What that means is that this type of system as opposed to a system with a mass air flow sensor,is that there are already a set of parameters in the computer.(actually it's really a microprocessor)What it does is measure all inputs from the various sensors,(i.e. o2,map,temp,etc.) and has a "chart" that it programs from.Let's say for example,that you are at 2800 rpm,18" vacuum,190 degrees temp,the computer says,"based on what I'm reading,I will supply this much fuel".Now you change all of that,and the computer has no info now because the sensor readings are not according to the computers map.So the computer has to guess.It get's very close,but it cannot change it's "map".It's only programmed one way.What you might want to do is use a fuel enrichment device,like those found in "Turbo" magazine or one of those rice burner hop up magazines.What your'e doing sounds interesting to me.
Reply With Quote
  #3  
Old 09-02-1999, 08:47 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Post

Thanks for the input Christopher! Yea, I agree, it should be an real interesting project, if it works!

Okay, it just dawned on me last night that the factory computer and the JET chip that I have will be upstream of the supercharger. That is, the computer will not "see" boost pressure at all, it will always read a vacuum.

But when I nail the gas and the supercharger winds up, it will be pulling a lot of air and create a vacuum, a BIG vacuum.

I guess I'm thinking (hoping) the OEM computer will understand and cope with a vacuum better than it would cope with pressure. My thought is that a vacuum is a vacuum, regardless of the amount. The
highest (lowest?) vacuum it will ever see is zero, which is what it would be reading only when the engine is shut off (no airflow at all!), or when the gas pedal was really floored.

Now when the engine is fitted with a supercharger and the gas is floored, the supercharger will be creating a vacuum. At the boost levels that I'm looking at (5 psi max) I'd have to believe that there wouldn't be that much of a change in vacuum to confuse the computer. Surely it could find a close value on the map that it's programmed with. And don't forget, the JET chip will be modifying the OEM map to increase the fuel supply.

I'm going to bet that using a supercharger with the OEM setup will work as long as the computer is upstream of the supercharger air inlet, and as long as the fuel supply, ignition timing, coolant temp, etc. are all in the right ballpark.

Also keep in mind that this is a daily driver, I won't be on the gas all the time. I'm simply doing this to make it a little more competitive on the highway and getting onto the on-ramps. I won't really be hammering on it all the time, just a short burst every now and then for passing big rigs and the likes.

Any other thoughts, opinions, contradictions? Let me hear them. I can't afford to fry a computer because of my ignorance and/or high hopes.

Thanks,
400Magnum
Reply With Quote
  #4  
Old 09-03-1999, 01:37 AM
Christopher's Avatar
Christopher Christopher is offline
Inactive User
 
Join Date: Mar 1999
Location: fl
Posts: 2,018
Post

I agree with all you have said.However as a safety precaution,some type of "vacuum amplifier" may solve this.The older Mopars had one of these as a emission device,and although I don't know how much vacuum it really amplifies,this or something similar may do the trick.
Reply With Quote
  #5  
Old 09-03-1999, 03:43 AM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Question

I'm sorry Christopher, I'm afraid you lost me. What would I use the vacuum amplifier for?

I'd almost think that I'd need a reverse vacuum amplifier. My reasons are:
1. In normal driving conditions on a naturally aspirated engine when at a nice steady cruising speed, the engine is going to see the most vacuum, read a certain throttle position, O2 sensor will be reading a good mixture, etc. At this point, it's going to advance the timing and cut back on the fuel required.
2. In an acceleration situation on a normally aspirated engine, the vacuum is going to drop to almost zero, the throttle position will be wide open, O2 sensor will be running lean. The computer looks up the parameters on the map and realizes it needs to send fuel and retard the timing.
3. In a normal situation on a supercharged engine, everything will pretty much be the same as on a naturally aspirated engine. No real variation here.
4. In an acceleration condition for the supercharged engine, there will be a mix of confusing signals going to the computer. The vacuum will be even higher than at cruise (so send less fuel, advance the timing), the O2 will be running very lean (send more fuel, retard the timing), throttle position sensor is wide open (send more fuel, retard the timing).
Will it take best two out of three?? I almost need to have a reverse amplifier for this condition. That is, when the supercharger creates a bigger vacuum by pulling in more air, I need the computer to see less vacuum so it sends more fuel and adjusts timing accordingly.

I guess I just wish I knew what the limits of the parameters were in the OEM computer. How much vacuum can it handle?

Please explain in more detail what you meant by using a vacuum amplifier. I guess I'm just not seeing things from the right direction or something. It sounds like I may be able to use that in some way, I'm just not sure where or how.

Thanks Christopher for helping me think this one out. I really appreciate it. Who knows, this may turn into something really cool!

Regards,
400Magnum
Reply With Quote
  #6  
Old 09-03-1999, 02:16 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Lightbulb

Christopher!

In my excitement about getting this idea, I forgot about the MAP sensor coming into
play in this whole thing. I guess I was so concerned about what the computer was going to see in the inlet air duct that I forgot about the rest of the package.

As I said earlier, I was going to have this set up so the computer would be upstream of the supercharger, so it would not see any boost. It would always read a vacuum, at least where it was sampling the air.

However, now that the MAP sensor comes into play, I realize that the computer will see boost.

But, what would happen if I relocated the MAP sensor and put it on a vacuum reservoir? That way, when I'm at cruise, the MAP sees the normal amount of vacuum that it would see in a naturally aspirated engine. When I hit the gas, the vacuum in the reservoir will
drop (either due to the use of vacuum or by the addition of pressure from the supercharger) and the computer will still see vacuum. Only it'll see low vacuum, and that combined with the reading from the
throttle position sensor will tell the OEM computer that I'm trying to accelerate, and in turn send more fuel and retard the ignition timing. When the OEM computer sends the signal to send more fuel, the JET chip will simply increase the proportions and make
more fuel/timing available.

Am I making sense, or am I way off base here?? Again, keep in mind that this is only going to be for short bursts. Hopefully, the vacuum reservoir will be able to supply enough of a low vacuum signal to the computer for a long enough period of time that the OEM computer will function. Perhaps I can use the vacuum reservoir in conjunction with the vacuum amplifier to maintain the vacuum signal for an even longer period of time so that I can maintain boost situations for a longer period of time!! WOW!!

Keep those ideas coming!!! This is great!!!

Regards,
400Magnum
Reply With Quote
  #7  
Old 09-03-1999, 05:29 PM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Wink

Hey guys, I am watching this one real close. I have a 91 Power Ram 318 with the throttle body injection, and in 8 years I have had it, I have never found a positive way to change the performance, with the exception of initial advance adjustments while the temp sensor is off-line, disabling the computer. Other than that, I know the Mopar Performance ignition upgrade has instructions to replace this setup, but that means you have to go to a carburater instead of injection.
Reply With Quote
  #8  
Old 09-03-1999, 07:01 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Post

Yea Brian, MP also makes a kit to convert the 3.9L over to electronic ignition, and of course, the carburetor.

I guess I've gotten spoiled on fuel injection on my daily driver. It's soooo nice to go out in the morning in the dead of winter, hit the ignition and the thing is running. No pumping the gas, no cranking and cranking till the battery is near death, no stalling or stumbling until the engine is good and warmed up. Of course, if I went to the electronic ignition and carburetion, there are many more parts direct from MP that boosts performance of this little six. They've got an M1 manifold, ported heads, and several cams. Plus, with a little creativety a person can adapt a lot of parts from the SB. Things like pistons, rods, roller timing chain, oil pump, etc.

I don't know, it just seems like there should be so much more that could be done with this setup than what is being done. This little engine has the potential to combine the longevity of the 318 and the old slant six with the performance level of a nice small V-8, but the factory engineers just didn't seem to put a lot of thought into it or something. For instance, the new Magnum 3.9L puts out more horsepower and has better economy than the 318's from this era of trucks that were talking about here.

If this setup works with the 3.9L, the same thing should work with the 318's and 360's of that era too. And I always hear the same complaint from owner's of those trucks, they want more power for all the more fuel economy they have, or they want more economy for all the more power they have. Either way, if I can figure out the particulars with my truck, the same principles will apply to your Power Ram, and I'll be more than happy to share with anyone who wants to know what I did.

I can't believe some of the responses I get from the aftermarket suppliers and even Mopar concerning these trucks. Everyone just sort of ignores them. I usually get a response like "We don't make anything for those trucks." And you can tell from the tone that they aren't even going to consider making something for those trucks either. But what they don't realize is that no one else is making anything for them, so if they were to make something, they'd have cornered the entire market of people looking for these parts. It gets so frustrating sometimes.

Anyway, keep watching this thread. I'll keep it alive as long as I can. Hopefully, between all of us, we can figure this thing out someday.

The unfortunate thing is that even after I get a supercharger (assuming we all figure this out to the point where it looks like it will work) it will take some time for me to fabricate the necessary brackets, inlet and outlet ductwork, belt routing, and I'm sure a whole lot more. So I'll just have to start up a new post later when I finally get the truck running and give the results then. If I'm real lucky, I may have my own web page by then and I'll just post a bunch of pictures and data on it and take it from there.

Thanks for the input! Let's keep thinking about this one!!!

Regards,
400Magnum

[This message has been edited by 400Magnum (edited September 06, 1999).]
Reply With Quote
  #9  
Old 09-03-1999, 11:17 PM
Christopher's Avatar
Christopher Christopher is offline
Inactive User
 
Join Date: Mar 1999
Location: fl
Posts: 2,018
Post

I thought about a vacuum resorvoir also.Mounting the map sensor there is a good idea.The vacuum amplifier could be hooked up to run backwards,but the resorvoir would work best,and a lot easier too.Plus the amplifier would have to be wired in with the computer to trigger it,and I can't see going thru the mess.I like to do it easy!!!You'll have to open up the exhaust to at least a 3" system, if you run the stock type pipe routing,but I think this is a great idea.Keep posting your results and thinking.
Reply With Quote
  #10  
Old 09-04-1999, 02:24 AM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Post

It's all starting to come back now. 8 years worth. July 91, on the day I bought my truck, I saw a picture of an open hood view of a 3.9 Dakota in the 91 Mopar Performance Catalog. The velocity stack and the stance and tires etc said this truck gets raced. I looked into it, no one knows anything about it. I hear about a couple of short bed Dodge 4x4's that are making waves in off-road racing. So I try to find out more about Walker Evans, all I can find out is that he runs a Dodge. The magazines don't even give any specifics about the power train. So I try my luck with the other guy, I forget his name, but Dodge actually had a 4x4 package truck with his name on it at one time. By the time I track him down, he is running Hummers in Las Vegas and it's like he never had a Dodge according to his web page. Now I find the tech line, the Magnums are out, and they don't know nothing about a throttle body. At least my dealer is on my side, he is new to Chrysler, and he is tweaking my trucks timing in one degree increments and we get some response at 13 degrees initial advance and tire change to 31x10.5x15 instead of the 235x75r15 original equipment. Oh, and the truck is on my side, it is drop dead reliable, I can't believe what it tows. I pull a 2500 pound boat trailer, plus what ever gear I have in there, the box is loaded to the top of the canopy, and I am making 2000 mile trips with the cruise on and it's in over drive. All I have to do is push the little OD button at the foot of the hills, and push it again as I go over the top. But back to business, the only after market guy that trys to help at all is the guy that makes the throttle body spacers for the chevs. I call his number and fluke out and actually get to talk to the main man. He says he never thought of the Dodge, but he is starting to warm up to the idea real fast, he smells a dollar. Then he remembers that the magnums are out, and he recomends I take a look at one of his chevy ones and make my own for a Dodge. He says it will work the exact same, I don't bother, and now here we are. I may even try all the things you do, or just some. Oh yeah, I called Holley, they admitted they made the injection unit. But they don't know anything about them, they don't even know if it would run with one of their computers instead of the factory one. Maybe I'd like to buy one of their complete units? O.K., how much? Uhhhh, uhhhh, we don't even have anything for your truck. Is it a magnum? No , oh well. Some body had to have done something with these things. If I can help any way, search the web, study a book or make phone calls, just let me know. Brian

[This message has been edited by Brian Mills (edited September 04, 1999).]
Reply With Quote
  #11  
Old 09-09-1999, 01:51 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Post

Okay, I've been posting the same sort of questions on another Mopar forum board and one of the points brought up there was that the vacuum reservoir may hold too much vacuum for too long of a time, not letting the MAP sensor ever get to zero vacuum. So it would seem that I need to experiment with vacuum reservoir capacity, which leads me to my question.

Does anyone know where I can purchase an adjustable capacity vacuum reservoir, or can you tell me how to make my own vacuum reservoir? If I knew what it took to build one, I've got some ideas on how to be able to fine tune it to get just the right amount of vacuum for just the right amount of time, but I'm not sure what it takes to hold the vacuum.

Should I post the question on how to build a vacuum reservoir in the High Performance section too?

Any advice or ideas would be greatly appreciated as always.

Regards,
400Magnum
Reply With Quote
  #12  
Old 09-10-1999, 01:45 AM
Christopher's Avatar
Christopher Christopher is offline
Inactive User
 
Join Date: Mar 1999
Location: fl
Posts: 2,018
Post

There must be some way to bleed off excess vacuum,but I have no idea how.Crane Cams has a vacuum resorvoir,and those old big fords had one that looked like a small coffee can.Look at those and see if that's what you need.
Reply With Quote
  #13  
Old 09-10-1999, 02:52 AM
5DodgeGuy 5DodgeGuy is offline
Inactive User
 
Join Date: Sep 1999
Location: Broken Arrow, OK, USA
Posts: 31
Post

I don't know if it will work in your situation or not, but, one of the tricks to increase boost pressure on the early 2.2L Turbos was to install a bleed valve in the vacuum line to the wastegate solenoid. You can pick up these bleed valves at any fish supply store. It is the bleeder valve for the air line in the fish tank.

I believe the old "Direct Connection" books used to mention them.
(That shows my age)

Hope that helps.
Reply With Quote
  #14  
Old 09-10-1999, 04:07 AM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Post

Okay, that's a good idea guys, Thanks! Some way to bleed off vacuum. Ideally, I'd think the best way to do that would be to have the vacuum bleeder linked to the throttle position sensor so that it would bleed off lots of vacuum when the throttle was wide open, a something less than that at about 75% throttle, etc., or whatever the actual settings may be. I'm sure some experimentation would still be needed to find the right setting.

I'll have to look in the local pet store this weekend for one of those bleeder valves. Is it a manual device, or is it controlled electrically, or what?

As a side note, I was also wondering about the brake booster. That is, it gets vacuum from the manifold to get the power assist for the brakes. What do the Turbo cars do for power brakes? Is there a one-way valve in the booster to prevent pressure from entering it? If there is a one-way valve, could I somehow use it and a small capacity vacuum reservoir that I install the MAP sensor into?

That way, when I'm at idle or cruising along nice and easy, I have a normal amount of vacuum in the reservoir, and the computer reads that and the throttle position and knows exactly what to do.
Then, when I nail the throttle, the vacuum gets used up almost immediately and drops to zero in the reservoir. The vacuum signal to the MAP sensor then goes to zero, but since the one-way valve will not allow pressure to go into the vacuum reservoir, the MAP sensor will only read zero vacuum, and that combined with the throttle position sensor, the computer(s) will read off the necessary parameters from the programmed chart to send a lot of fuel and adjust the timing accordingly.

The net effect is that the MAP sensor reads vacuum when needed, but never sees pressure.

Actually, I'm starting to wonder if I need a vacuum reservoir at all. Could I simply install a one-way valve between the MAP sensor and the intake manifold? That way, the response to vacuum variations would be almost instantaneous, instead of having the lag time that would be involved when using a vacuum reservoir. And the one-way valve would prevent the MAP from seeing boost pressure, which is the only reason I was considering the vacuum reservoir in the first place.

So, round and round I go. Is there such a thing as a one-way vacuum valve? If there is, where would I find such a thing? Is that what the fish tank bleeder valve is? Any chance that they are sensitive enough to be used with the levels of vacuum and boost that we're talking about here?

Well, what do you all think of this idea? Are we getting closer or are we just going around in a viscous circle?

Regards,
400Magnum
Reply With Quote
  #15  
Old 09-10-1999, 04:32 AM
Christopher's Avatar
Christopher Christopher is offline
Inactive User
 
Join Date: Mar 1999
Location: fl
Posts: 2,018
Post

Getting very close if you ask me!!! The one way valve makes very good sense.I know Mopar used some of these as I used one to delay the opening of my distributor vacuum advance on my car when I had a 10:1 motor and a wild cam so it wouldn't ping on 93 pump gas.I think they used these to stop the drop in vacuum at the A/C doors when the accelerator was punched and you'd lose A/C at the vents,then it would come back.These type of valves were used on B series Dodge vans and Chrysler 5th ave's.
Reply With Quote
  #16  
Old 09-10-1999, 01:53 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Post

Could you tell me what these valves look like on the 5th Ave's and Vans? Where are they located? Would it be safe to assume that they were used on any vehicle that had air conditioning?

And what about the brake booster? Do I need to scavenge something from the front wheel drive Turbo cars that allows my power brakes to function? The last thing I need is to lose all braking ability right after I've been under boost!!

Thanks again!
400Magnum
Reply With Quote
  #17  
Old 09-11-1999, 08:36 PM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Biggrin

A friend of mine was just muttering something about one way vaccum valves this past winter in my garage. We were swapping out the factory rottenchester on my Ramcharger for a Thermoquad. Carb change was complete and we were tuning the distributer advance. He was reluctant to hook up the vaccum advance, went in to a big speel about towing and the short trip severe weather winter running this truck would see, and he made mention that the general has a good selection of one way valves used in production on various chevs and gm's. Now my friend is a Mopar Man, and I don't want to mislead you, but you may find a one way valve to suit your purpose in the chevy part room. I've also had the local Polaris dealer instal one of these on an Indy 500 I had years ago just because they could supply it quicker than Polaris. On the Dodge front, I have come across vaccum delays, and the one way valve for vent dash pots, but not very often. Hope this helps.
Reply With Quote
  #18  
Old 09-11-1999, 08:44 PM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Biggrin

Also for power brakes on a turbo car, try Cliff Sebring in front wheel drive chat, he'll know about all of this stuff, stock and mods.
Reply With Quote
  #19  
Old 09-12-1999, 06:46 AM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Post

Okay Brian, thanks for the tip on the vacuum valves. I don't have a big problem using a small Chebby part on my Mopar, especially if I can go to the local parts store and get the generic equivalent. But Polaris parts, that would be really cool!

Oh, I've been racking my little brain trying to remember that guys' name that you brought up several posts ago, you know, not Walker Evans, but the OTHER 4x4 guy. Well, I finally remembered early this morning. It's Rod Hall! That was driving me crazy trying to remember his name. I can remember when the trucks came out that had his name on them and were built a little like his Pre-Runner truck (okay, very little). Anyway, I just wanted to pass his name on to you.

Thanks again for the information about the vacuum valves!

Regards,
400Magnum
Reply With Quote
  #20  
Old 09-12-1999, 05:01 PM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Thumbs up

Yeah 400 that's the guy. If I get a chance I will ask the Polaris dealer if he remembers that little job and see if I can come up with a part#. By the way, have you found any people in your travels yet who can do any mods to this system other than supercharging?
Reply With Quote
  #21  
Old 09-12-1999, 11:19 PM
Christopher's Avatar
Christopher Christopher is offline
Inactive User
 
Join Date: Mar 1999
Location: fl
Posts: 2,018
Post

They are located in the A/C vacuum line going into the firewall.There about an inch in diameter and If I remember correctly most are green in color.
Reply With Quote
  #22  
Old 09-13-1999, 03:30 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Post

Okay guys, thanks for the tips on the vacuum valves. I'll keep my eyes open for them in the local junkyards and go get one from Polaris if you can find that part number for me. Sort of do a side by side comparison between it and the Mopar units, see if one or the other is more sensitive or reacts faster or is more rugged and holds up better.

Brian, I've contacted Magnum Performance about modifying my throttle body. They said that they could work on it, but that most guys with these throttle body units don't get stuff done to them. They didn't seem to want to do it, and they didn't give any information on what they could do or any prices for what they'd do. They just didn't seem too anxious to take on the job, and with their lackluster attitude, I wasn't too eager to send them my throttle body. I guess I'll have to come up with something on my own.

From what my digging around has uncovered so far, all of the typical modifications seem to still apply. Things like aftermarket ignitions still can be used, like any MSD 6 series, or Crane Fireball HI-6, or the Jacobs stuff, along with a good coil and spark plug wires and spark plugs.

Crane makes two camshafts for the pre-Magnum computer controlled engines. One person claims that the Mopar Tech line told them that they would be better off using a stock cam but getting 1.6 roller rockers. If you get roller rockers installed, you'll have to get custom length pushrods made by someone if you have an OEM roller-cammed engine and want to keep the OEM cam and hyraulic roller tappets. Of course, getting new pushrods made has a benefit in itself in that they'll probably be lighter and stronger than the OEM units. Any time you can take a little load off of the valvetrain, that's good. Plus, the new pushrods won't be flexing all over the place, losing valuable lift like the OEM units can do at higher rpm.

There are a few places to get headers and cat-back exhaust systems. Nothing real earth-shattering though. You can certainly find a good muffler, Flowmaster, Edelbrock RPM series, Hooker AeroChamber, Moroso Spiral Flow, just to name a few. Go to a muufler shop that custom bends pipes and get them to make a dual exhaust system for you. It's a little pricey, but it'll work.

So far, JET is the only place that I've found that makes aftermarket computer modules for these vehicles.

It's pretty easy to get things like a K&N or Amsoil air filter for almost any vehicle, except mine!

Also, you can still use a windage tray on any small-block. And you can use a double roller timing chain and sprocket set on any small-block as well. If you install a cam (or even use the OEM cam) along with a JET chip, JET recommends keeping the cam installed in the factory setting of 0 degrees advance/retard.

And if you're tearing the engine down for a rebuild anyway, make sure you use some of the piston rings that essentially have zero gap in them. As far as pistons go, don't get any that have real high compression, anything over 9.0-1 will probably mess things up. However, there is nothing wrong with getting nice light-weight pistons and getting the entire reciprocating assembly balanced.

Another option is to get a set of the underdrive pulley sets out there. One article I read where the pulleys were used on a V-8 Dakota, the gas mileage increased by .5 mpg and the quarter mile speed increased and ET dropped. They seem to help a little.

I guess the key here is to look for things that take care of the basic engine functionality and do anything you can to improve engine efficiency.

I don't know whether getting better flowing cylinder heads will offer any performance improvement, but I'd think that it would. And I have to believe that a good aluminum dual-plane intake manifold would help too, since you're still functioning as if you were carburated. If nothing else, it'll save you a few pounds.

So many questions still left unanswered. The big problem is that with the Magnum engines out, there is such a huge market potential that everyone is catering to them, and ignoring the older TBI engines. Oh well, I guess a few of us brave souls (in other words, poor!) will have to take on the task...

Any other ideas?

Regards,
400Magnum
Reply With Quote
  #23  
Old 09-13-1999, 06:03 PM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Biggrin

1-6 rockers sounds good, I did see a set of ported 318 heads in the performance catalog, a little pricey, but a good time to re-work the valve train. I did consider an intake, but I know that I would have to make an adapter plate for the throttle body. By the way, Mopar Perf offers a complete fully ported head for yours as well, p4452747, $739.00 in the 98 catalog, I don't know if that is one head or two. As far as a cam, the tech line told me one time that the purple cams for pre-magnum engines will work in ours. I already have a new in package timing chain set for this. I hadn't considered pistons, mine has only 75000 miles on it. Windage tray is something to consider though. I didn't know if MSD would work, but this also sounds good. I don't know where yours shifts, mine is at 4000 at WOT, I have heard that there are weights in the transmission to control this shift point, might be worth looking in to some different weights to go with a shift kit. The Polaris dealer says his one way valve is used on a vent line, he doesn't think it will handle boost in your application, but he did talk about an electric vaccum pump, I don't know if this would help. You know you could just plug the vaccum advance and run with only performance mechanical, my Ramcharger is set up this way and I was suprised at how well it performs, I lost about 1/2 mile to the gallon highway, and thats imperial gallon which is 20% bigger than american. You are right though, we have the orphaned set up, I'll tell you if one thing goes wrong with that TBI, I'll go to carburetor before I'll re-do that thing. Oh before I go, the under drive pulleys, I tow from time to time, every set I've seen so far says not for towing, any idea what this is about? Brian
Reply With Quote
  #24  
Old 09-13-1999, 06:43 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Post

Brian,
Yea, I saw those heads too. I'd like to get them except for two things, #1, they're a little too expensive for my budget right now, #2, I'm not sure that TBI guys will see as much of a benefit as the carbureted guys. I'm still trying to figure that one out.

Thanks for checking on the Polaris valve for me. I'll have to look into the electric valve, but I'm guessing I'll probably end up just using one from the boneyard at first.

Yea, the reason that they probably don't recommend the pulleys for towing is that the power steering will run slower, so there might be some concern about safety, plus the water pump will turn slower, so there may be some concern about overheating. However, if a person were to use a higher flow rated water pump to start with, it may be okay.

I thought of a few other items that us "older generation" injected guys can use is synthetic oils and gear lubes. I've heard several people say that it'll free up a few horses under the hood, plus cut down on the number of times that you have to change oil.
And it should help things run a little cooler, which has benefits of it's own as I'll explain below.

Another thing to do is to use a 180 deg thermostat. It'll tell the computer that the engine is running a little cold and the computer will send a little extra fuel to warm things up. When I bought my JET chip, they recommended getting a 180 degree thermostat to replace the factory 195 degree thermostat to prevent pinging. I told them that I'd found a 160 degree thermostat and asked if that would be better, and they said that it wouldn't. That it'd go too far and just cause the engine to run too rich and clog up the catalytic converter(s) and just waste a lot of fuel with little to no benefit.

Granted, neither of these items will make a huge difference, but if you start adding up all the little things, eventually a few ft-lbs of torque here and there will make a noticeable difference.

I don't have a vacuum advance on my distributor, it's one of those new-fangled Hall Effect distributors. That's why I went with the JET chip, because my distributor really doesn't control anything except to determine which plug wire gets the spark next.

I'm sure the MSD/Crane/Jacobs ignition components will work with your truck. It's just a matter of money and spending a little time figuring out which is the right way to wire it up. I've in the process of hooking up my unit now. Again, not real clear which way I want to do it because they seem to cover every system EXCEPT for this era Mopar.
Geez, it gets old after a while.

I have a manual transmission so I can't say much about the shift points. I've read other posts around on this and other forums where the Transgo shift kit is highly recommened for ease of installation, good instructions, and good results. The general consensus was that it was better than the Mopar Performance kit for less money. Again, I have no personal reference point to draw from, this is just what I've heard (read) elsewhere.

Thanks,
400Magnum
Reply With Quote
  #25  
Old 09-14-1999, 06:56 AM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Biggrin

Right on 400! It does get old. I'll tell you about my results. When I bought my truck, the window sticker said 22 mpg highway, it got 14. I changed tires from 235x75x15 to 31x10.5x15, and it went to 18. I advanced initial timing from factory 10 BTDC to 20 in 1 degree increments, and then back to 13 as it performed the best and started better. There was no fuel economy increase. I put on a K&N air filter, nothing, except it lasts longer. I went to full synthetic 5w30, starts way better in the winter, no fuel economy increase. I put mopar 75 140 full synthetic in both diffs, 5 litres at $25.00 per, it rolls ahead off of a snow lump first thing in the cold winter morning when you pop it in to neutral for trans warm up. Previously you warmed it up, put it in gear, always forward first, reved it to 1000, and it moved in about 5-10 seconds. 1 mile up the road you would come to a red light, traveling 30 mph, take the foot off of the gas, and the truck would be stopped before you touched the brake. The synthetic changed all of this, economy increase, 0. At this point I'll mention that all economy measurements I have done are in the summer. The catalytic converter plugged on a highway trip, economy fell to 7.8. Cut it off, don't have to have it here, so I don't. Economy back to 18. Pulled the belt off of the air pump, 0 increase. Tried Bosch Plattinums, after 3000 miles it showed some performance gain, 1.6 mpg increase. Unfortunately they fell down big time in the cold weather start dept. On long highway trips, 3000 miles, I run Shell Gold, 32% further for 18% more cost. Everything goes back to normal on anything less than a long run, day to day driving, it just costs more. I have looked at the jet chip, and I don't understand why I want I want a thermostat to make the computer think the engine is cold. I'll tell you what I do like, and you should look at it as well. Those M1 intakes with the bosses for future Multi Point Injection. Especially when they are sitting on a 380 horse crate motor. If the future was tomorrow, I'd have one in my truck the day after, you know what I mean? I must admit, I'm not real keen on your super charger idea. I think you should buy a V8, but if it works, I'll probably want to borrow your recipe. I didn't mean to bore you, but like you said, it gets old. Brian

[This message has been edited by Brian Mills (edited September 14, 1999).]
Reply With Quote
  #26  
Old 09-15-1999, 10:36 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Post

Brian,

Hey man, I never get bored reading about this stuff, so just talk all you want. I just never know when I'm going to learn something!

Thanks for posting all the stuff you've tried and the results. I may have to look at increasing my tire size and messing with the timing. I was looking at getting a set of lower gears (3.23 instead of the current 3.91), but I need a new set of tires too, so I may as well just get a set of slightly taller tires that will help with the gas mileage in the process and not even mess with the gears.

I may play with the timing a little too, just to see if I can get better performance without affecting the gas mileage. I just assumed that the computer had everything like that under fixed control, but I guess it doesn't! COOL!

I bet you were a bit dissappointed with the results of the synthetic oil and lube, I know I would be. Sure, there are other benefits to running the synthetics like you mentioned, but the one I'm after is better gas mileage or improved performance for the same gas mileage.

If the money situation ever gets better, I would love to stick a Magnum V-8 in my little truck. It'd be a blast! However, as things are, I can barely afford to fix up the six, and I really need to get the best gas mileage that I can, so I'll just have to keep putting that one on my "To Do Someday" list.

I hate to sound like a broken record, but I was looking at this whole supercharger thing as a means of keeping the economy of the 3.9 while getting a little better performance, much like Ford did with the Super Coupe T-birds. The main thing that made me even think of it is that I can get a supercharger from a freind pretty cheaply. And it was just one of those things were I started wondering if it could be done, and why no one else has ever done it.

The thing that I'm afraid of with the supercharger is what Ford experienced. They bolted on the supercharger, and then proceeded to find every other weak link in the drivetrain. I can't afford to replace much, even though I already know that the clutch is about to die on me, which is one reason why I'm keeping boost relatively low. It should keep any extra stress to a minimum when boost is applied.

I've thought about the M1 manifold and the multi-point fuel injection. There is a company in Canada that makes aftermarket fuel injection and ignition units for a decent price, but it's still more than I can afford for now. (click on the link to see their web site)
http://www.sdsefi.com/

And I've thought about installing the heads from a Magnum V-6 onto my V-6. One of the Mopar mags did a similar thing to a small block a few issues back and got a nice gain in horsepower and torque. But again, the conversion cost is just more than I can afford for now. And if I did have that kind of money to spend, I would just get a V-8 and drop in there and be done with the hassles.

I've sent an email to a guy that has turbo-charged a couple of slant six Valiants and asked him about the brake booster to see if he's had any trouble and what he did to fix it if he did. Haven't heard back from him yet though.

I also have done some looking for a one-way valve. It looks like I can get one brand-new for about $6, and be able to specify at what pressure it opens & closes, so I may do that rather than scavenge something from the boneyard.

Regards,
400Magnum
Reply With Quote
  #27  
Old 09-16-1999, 06:45 AM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Biggrin

Right on 400, I like to blab on sometimes. If you want to adjust your timing, you can only adjust initial advance. The computer will counter every move you make, unless it is not getting full input. The engine temperature sensor is on top of the intake manifold behind the thermostat housing. Unplug the wire, and you can adjust initial timing. The computer will in effect be blind as long as the data is interupted from one of the sensors. The one really nice thing our system has is a medium loop, it has other names, but it is like a mechanical default setting. When my truck was 3 weeks old, the main comp. or SMEC burned out, it was faulty. The truck didn't quit. The system just went into a loop where it got enough gas and spark advance to run at normal speeds under any conditions. By conditions, I mean I could be in 4 or 2 wheel drive, air on or off, idle or highway speed. It gets the same fuel flow through the injectors at idle as it does at any speed. Needless to say, the first sign that it is in loop is a noticeable drop in economy, I never did get a fault code or light at any time. The next thing to realize is that all the little sensors get old and inaccurate. Example: The engine temp sensor tells the comp that the engine temperature is 132F when the real temp is 180F. Does the comp trip a code, NO. 132 is an acceptable temp for the engine to be at. The comp sends fuel to warm up a cold engine. Only when the sensor send riddicules data, like the engine temp is 500F, does the comp see a problem. Then it trips a code. Of all the sensors, the MAP, or Manifold Absolute Pressure sensor has the greatest impact on fuel delivery. This is the one that measures the amount of vaccum in the intake manifold. When my catalytic converter plugged, this is the guy who saw less vaccum, so he sent more fuel. This is the guy who knocked over 10 miles per gallon off my economy in the space of one 400 mile trip. Thats a Canadian or Imperial gallon by the way, 20% bigger gallon than an American gallon. I was quite surprised to find out this system could even deliver this kind of fuel, much less that the 318 could burn it. And even more so, driveability was not compromised, I'm out passing on the highway at 75 MPH, the gas gauge is dropping like there's a hole in the tank. If you were to put some kind of electric control on any sensor, the MAP would be the one. As far as I know he works on 5 volts, but be careful, I would suspect the lean out capability is just as strong as the over fuel capability. I almost think the factory sets them up a little rich just for this reason. I've always said that I could jack up the fuel injection, and replace the 318 with a 360, and be fueled at a better mixture than I am now. You probably guessed my next adventure is to change out and, and figure out the MAP sensor. I'll also be looking in to a JET chip. Faster timing advance has got to help here. One of the biggest things that I see as an effect on the MAP is vaccum leaks. My truck has always had a little whistle sound at the motor when driving. It changes pitch with RPM, and is most noticeable when coasting with the throttle closed, or stopping. Whan I re-seal, I'll probably throw in an M1 dual plane and see what happens. Your truck, I had an 83, 2wd, short box, slant six, 4 speed OD, with 3.23 gear. Sound familiar? Your V6 has more power, but comparisons should be close. Tire size was everything to this truck, and I had them all. Factory p195 75 R 15. Next P225 75 R 15. Next American Racing Mags, P265 60's on the back, P275 70's on the front. Back to factory. You have a 3.91 gear, don't lose it! If you can get a set of mounted tires from anybody to bolt on, do it and go for a drive. I'd start with 31x10.5x15 if you can find some. They are the biggest tire recommended for our truck that still uses factory off-set, and wont rub under normal conditions. You can get away with 32x11.5x15, I've even seen them from the factory on 4x4s in 86. B.F. Goodrich makes a 33x9.5x15 in an all terrain. I've seen good results with them, however you can still run into rubbing at the bottom rear of the front wheel well on corners, especially if you have running boards. Most guys don't cut the wheel well, they just put a porta power behind the wheel and bend the fender a little. Stay away from anything that has 35 psi max pressure, they have a soft sidewall enabling them to have a bigger footprint when off-roading. It's O.K. if you want that, but it costs fuel economy to have that big tire flexing. How much power does your truck have now? What size tire are you running? Does it feel like your truck could accelerate faster? Don't be afraid to make that motor grunt a little. Throttle body injection by nature has better bottom end power, use the tourque band more by using bigger tires. I got saddled with too big of a tire on my 6, but you have that gear in your favor. If I knew factory tire size, I'd almost recomend 31x10.5's. My 91 has 3.5 axle, so you have more gear. Mine is 4x4, so yours is lighter. Mine is automatic so it takes more power to run than your standard, and my OD is .69-1, yours is about .75-1, so even with the same gear, you would rev higher on the highway. Just a few things to think about 400. Oh yeah, let me know how the MSD works out, I'm thinking about one of those. I'm also going to the Champion Truck plug and Magnacor wires. You have a good day. Brian

[This message has been edited by Brian Mills (edited September 16, 1999).]
Reply With Quote
  #28  
Old 09-16-1999, 06:49 AM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Question

How do you seperate your paragraphs, I used the space bar, and it still bunched up. I tried the tab before with no luck. Brian
Reply With Quote
  #29  
Old 09-17-1999, 03:15 PM
400Magnum 400Magnum is offline
Senior Member
 
Join Date: May 1999
Location: Grand Ledge, MI, USA
Age: 60
Posts: 239
Exclamation

Hey guys, I've got the answer to the MAP sensor/brake booster problem!!!

I sent an email to a guy that has turbo'd a couple of slant six Valiants in his day, and on one of them is in installing an EFI setup, so I thought he might be a good source of information. Turns out that he is, and was really interested in the proposed project of supercharging the 3.9L with a T-bird setup.

Anyway, to make a long story short, I asked him about what I could do to prevent the MAP sensor and the brake booster from ever seeing boost pressure as I didn't want to damage anything or confuse the computer and listed all the other concerns. I also told him about the ideas that we've kicked around here and asked what his approach would be.

The answer is so simple I feel kind of dumb for not having thought of it myself, but I guess that's why this forum boards exist, right? Anyway, the answer is to relocate the MAP sensor and the vacuum bleed for the power brakes UPSTREAM of the supercharger, preferably between the throttle body and the supercharger inlet. That way, they both always see a vacuum. At cruise, there will be the normal amount of vacuum that there always was. When I nail it, the vacuum drops but will remain a vacuum or zero vacuum/pressure under the most extreme duration of applying boost. Problem solved, and it's a nice simple and effective solution.

He also suggested getting an auxiliary fuel injector to add in the system to make sure that I don't run lean under boost. I can get one for about $90, which seems like a reasonable amount, but I'll probably just try the JET chip for a while to see how it does. Drive it for a while and read the plugs after a full throttle pass or two to see what they look like. If they appear to be running lean, I'll get the extra injector. But from what you're saying about you're truck Brian, it sounds like the OEM injectors can flow PLENTY of fuel if needed.

Of course, that'll be after I start gathering up all the other parts, which I haven't started yet. So this will be a while to see this project to the end. There's going to be a lot of bracket fabrication too, which will be interesting since I've never done anything like that either!

Anyway, it looks like the foreseeable problems have been worked out here. If there are any other thoughts or comments about this I'd still really like to hear them. There is probably something else that I haven't even thought of that could stop everything.

But I would like to thank both Christopher and Brian for your input, thoughts, results, etc. You both helped a lot! THANKS!

Brian, to answer your question about the paragraph spacing, all you have to do is hit the "return" key twice to create an empty line between paragraphs.

I'll give that a try on adjusting the initial advance. And you convinced me to keep the 3.91 gears and go with the tires instead. I didn't really want to get rid of the gears anyway, I mean, I like to have fun too every once in a while! And it's a whole lot easier to change a set of tires than gears! I can get a set of 31-10.5's for the week when I need the gas mileage, and then if I want to have a little fun on the weekend I simply swap to 245-60's or whatever for a little extra handling and acceleration potential.

I don't really know how much power the truck is going to make when I'm done. I know what all of these people claim there parts will add, but I'm sure that they are exaggerating some. I should be getting the old girl back together by next weekend, and then when I see how she drives with all of the modifications, I can judge what tire size I'll go with.

I'll let you guys know how the first stage of the 3.9L project turns out when I get it all back together!

Regards,
400Magnum
Reply With Quote
  #30  
Old 09-17-1999, 04:32 PM
Brian Mills Brian Mills is offline
Inactive User
 
Join Date: Jan 1999
Location: Ft.McMurray,Alberta,Canada
Age: 64
Posts: 624
Thumbs up

Perfect!

Is that return key working.

Seems to be.

Yeah, I was thinking about the adaptability of the stock fuel injection for this application after I wrote that last post.

Imagine the results if this works out, and you scrape up enough for those ported heads later. I know my interest level just peaked out at excitement.

Tell me about the blower, it must be a manifold mount. What year and car do they come in? Are they hard to get? Will it be difficult to mount it?

I'll leave it at that for now.

Oh yeah, maybe you'll start a craze, and Andrew will have to give us our own section for Older Throttle Body and Superchargers. Wouldn't that be cool!!!

Brian
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
89 Throttle Body Injection System DanL Dakota Truck Forum 2 01-22-2004 11:10 PM
LPG Propane-Fuel and Superchargers Herman Power Adders 8 11-30-2003 10:18 AM
Fuel Injection TrxR Performance Talk 25 10-28-2001 05:41 PM
Fuel injection for a older car 55dodge Performance Talk 6 03-14-2001 04:11 PM
300 plus in 89 w/throttle body injection totrade Performance Talk 2 12-23-1999 07:54 AM




All times are GMT -4. The time now is 06:39 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
. . . . .