Turbo System Designs

[threefortyduste]

Ok..i am planning on turbocharging my dakota within the next year. It will be a twin turbo set up with turbos off of 2.2L chrysler motors. I am going to be making the headers with flanges to be used, i just need to know about the carburetor deal. Where can one find a blow through carburetor? If you know of any, please let me know.

Second...the intercooler....i need an intercooler that looks like this, with the red being inlets, and blue being the outlet, or one close to it...since the twins will come from different sides of the engine. Any help is appreciated
http://img22.photobucket.com/albums/...r/ICneeded.jpg

[flight704]

I am NOT trying to deter you because I am turbocharging my dakota in a blow through carb mode , It can be done but it is easier to go injection if you have the option. You will make more power in an injection setup over carbs because of the boost limitations.

I would buy corky bells book maximum boost. I got mine at barnes and noble if you dont have one of those i know for sure you can get it online at amazon .com its like 25 or 30 bucks.

first on the carbs , you need to figure out which carb you are using and then find out how much boost it can take .you need an adjustable boost indexed fuel pressure regulator. set base pressure that carbs are rated for for normal use. then the fuel pressure raises at a one to one ratio with the boost. if you dont have this or the boost pressure will push the fuel backwards , motor leans out and boom!!!!!!!! There is the option of putting the carbs inside an air tight box and then just pumping the boost into the box. i thought it would be alot of headache to seal the fuel lines linkages and stuff airtight so i didnt do it. but it can be done. but i cant help you with that sorry.

example base pressure 4 psi for the carbs and then with 5lbs boost fuel pressure goes to 9 psi. I am using an aeromotive pump inline filter and regulator. here is a link to thier systems page all of these are designed to work together.

http://www.aeromotiveinc.com/system.html

i have the street rod /bracket car system on that page. its good for 200 to 750 hp. here are the part numbers inline filter 12303 pump 11203 regulator 13301 you can look the individual parts up on summit or jegs website and get individual pricing or specs.but you can buy the complete kit in one shot if you are so inclined. i bought mine 1 piece at a time , lack of toy money lol

bad side of this setup is the carbs have a limit to how much boost you can pump in them. each carb is different. I am using weber 45dcoe sidedrafts on my set up and they said i can run 10psi all day long with no problems but if it gets over 15 i will start breaking the carbs.

well that is basically it . the rest is figuring out how much you can get away with. I hope this helps out some and good luck in your quest for power and hold on to your wallet

[flight704]

i forgot to address your ic question.. link didnt work for me so i never saw a pic of what you wanted but spearco makes some good stuff. I am using two factory mopar ic's welded together. bottom tank solid 1 inlet with two outlets on top 1 to feed each carb. gary donovan does welding of aluminum to do custom intercooler work if you cant find one that suits your needs. he can be found here.

http://www.relentlessracing.com/

turbonetics sells the entire line of intercoolers from spearco. might be worth a call to find out if they have something
that suits your individual application. here is a link to thier site

http://www.turboneticsinc.com/

good luck and i hope all this stuff helps out.

[threefortyduste]

i cant do the injection...otherwise i would...but i think i figured out the intercooler problem...im going to switch to electric fans, move the radiator back, and put the IC between the grille and radiator.

but the fuel is going to be the biggest problem...mainly cuz carbs dont know boost...but any help you can provide would be great


edit: i dont plan on running more than 12 psi, so i just need a carb that can handle that

[turbododge]

A Holley spread bore double pumper is one of the best to modify for turbo. I ran one for 4 years on our TT340 Challenger. That said, it is extremely hard to get a turbo carb setup to run well on the street. The success rate approaches zero compared to about 10% or more success with EFI. Unless you are extremely good with carbs, I would wait until you can afford EFI. The 2.2 turbos will be a bit small if you are planning on doing a 360.

[threefortyduste]

Originally posted by turbododge
A Holley spread bore double pumper is one of the best to modify for turbo. I ran one for 4 years on our TT340 Challenger. That said, it is extremely hard to get a turbo carb setup to run well on the street. The success rate approaches zero compared to about 10% or more success with EFI. Unless you are extremely good with carbs, I would wait until you can afford EFI. The 2.2 turbos will be a bit small if you are planning on doing a 360.

i'm doing a 3.9 V6...but the 4150 series can be modified? if nothing else, i can pay someone to get the carb set up properly...but how hard is it to get it to run on the street?

[turbododge]

Any mechanical secondary can be modified to run boost, just no vacuum secondary setups. It is much easier if you have full metering blocks and pumps on both sides, and a spread bore makes it easier to get enough fuel under boost. Even with the best of tuning, there are some huge compromises in driveability. Our TT340 ran the best of any carb setups I have driven, but it still had things that were not good, but could not be remedied.

How hard it is to tune is based a lot on how picky you are on driveability. I am very picky about how well it runs and drives, and would not run rich all the time just to make it easier. If you do run it always rich, you are fouling plugs, washing cylinder walls, and getting poor mileage. You will never get it to drive as well as a NA car or EFI turbo.

To get it tuned to as good as you can get it for the street, and still make good power and economy, on a scale of 1 to 10, I would put it at 12. With EFI, I would put it at a 7.

Remember, at 12 psi, you will need to address boost retard for the ignition, and some kind of detonation control, like water injection (especially if you are carbed).

[jslikness]

For the carb, you need a vacuum hose running to the vent side of the fuel pump, and going to somewhere downstream of the turbo, so that as boost goes up, fuel pressure goes up (like flight704 said). Definetly get a book and read through it as many times as it takes to fully understand it. I read "Turbochargers" by Hugh MacInnes, but it's kinda dated, but has some real good info on turboing carb'd stuff. (It was written in '84). I will be getting Corky Bell's book soon though.

Also check out http://www.toohighpsi.com . I know it's Ford stuff, but it will help you out to see some of their setups. Mainly check out the TT351 Capri. It has a REAL low-buck approach to the twin turbo carb'd setup. I think the 2.2 turbos should be good for the 3.9, we were thinking about going with the same setup for one of my friend's trucks, except I'm having a hard time getting him to understand that carbs and turbos can work together...

I think everyone's probably right, it'd be a whole lot easier and run better with EFI, but if you're like me, I can't plunk down a couple grand at one time for an EFI setup.

[jslikness]

Oh, and check out how he did the fuel enrichment on the Capri, he didn't want the part throttle and putt around town driveability problems, so he rigged up a fuel injector to supply extra fuel under boost. Not perfect, but he said the fuel distribution curve actually looks pretty good on the dyno.

And he's running IIRC, about 12-15 lbs of boost on a pretty much stock Holley 4 bbl. I think after that you have to start modifying stuff to keep the boost from leaking past the throttle shafts (which EFI applications have problems with also).

[Prochargedmopar]

you want to know how to set up a Blowthrough carb????
here is one link:

http://www.hangar18fabrication.com/blowthru.html

Here is a board that has a "carburated tech section":
http://www.turbomustangs.com/forums/...?s=&forumid=13

You can also check out www.vs57.com and it shows how to mod a carter/thermoquad type carb:
http://www.vs57.com/technical.htm

Click the "carburetor modification" section to the left.

Those links should keep you busy for a while.