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#1
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when do you need high stall?
Ive just finished building my 360.Its not a hardcore race engine but its not bone stock either. I was curious if I can still use the stock torque converter.
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#2
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Generally speaking it depends allot on how radical the cam is and how big the valves are. I prefer to be able to drive a car and feel when the power band starts to kick in as that is the point you want the stall, at or just below that since flash will bring it up. This way you are using all of your power band.
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#3
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Small blocks like to rev, the higher the stall the quicker it'll be. It depends on how much street driving you do. I run an 8 inch ATI 5300 stall on the street with a deep aluminum tranny pan and a big B&M tranny cooler. I even had a 10 inch 3800 Coan that wasn't enough. The best thing to buy is a custom built converter from ATI, Coan, Dynamic, Turbo Action,etc. Stay away from GER, Banana,etc.
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#4
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im glad someone asked this question. i have a 360 ram sst and want about a 3000 rpm stall ive heard great things about the tci converters. are they as good as they are thought to be?
any info woulkd really help me out im just tyrin to do all my homework and do it right. so i really apperieciate all the advice. thanks agian!! |
#5
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TCI used to have some problems but I've heard nothing but good about them lately.
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#6
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I'm going to use it mostly on the street. It has a mopar purple 268/272dur .450/.455 lift cam. I want to know about the torque converter before I drop it in and have to take it out. ...By the way, is that an aar fiberglass hood on your scamp?
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#7
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The converter is definitely not an item to scimp on, do it right the first time! Actually my hood is a cheapo $189 lift off from MAS fiberglass, it has no ribs and weighs nothing, held on with 10 dzus fasteners.
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#8
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Gagfitz: You should run fine with a stock converter. I am building a 318 with 360 J heads and have the same cam that you are going to run. The cam is not very radical and will work fine with a stock converter as you will have a strong low end and mid range.
I prefer to use the lower stock stall as I am looking for economy with power second on the list. The higher stall converters slip more and therefore will not get as good of economy. I try to build my V-8's to get 18 - 20 MPG for daily use. One trick that I also use is the Rhoades lifters. They bleed down at idle and then gradually pump up to full lift and duration of your cam by 3500 RPM. This will also help get the low end torque to run the lower stall converters. I have a 68 Barracuda with a 318, 360 heads, 252/252 .410/.410 cam that got 18.7 MPG on the highway with a 2.76 7 1/4 axle. I now rebuild it with a MP 260/268/44 .430/.450 cam, 9.2 compression, Holley 600 vac. secondary, 77 360 heads ported with 2.02 valves. I had to upgrade to a 8 3/4 axle with 3.23 sure grip because I blew up 3 - 7 1/4 axles in 2 years with the old combo. Runs stronger now. Have not gotten any economy numbers since the spedo is broken. I will have lost some MPG in the gear. |
#9
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cool. thanks for the info.
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#10
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Although I haven't used them, I know people who have, and I think the Rhodes lifter approach makes a lot of sense when looked at as a means to keep the whole package price down and streetable. Now if you really go off the deep end on converter flash, you end up with this.
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#11
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What exactly does a converter do?
And what is a lock-up converter? If your power band is higher, do you need a higher stall? What is a stock stall for a 318/360? |
#12
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Plum Crazy Chris,
The torque converter engages the transmission. It is like letting the clutch out at a designated RPM. The higher the stall speed, the more slippage you will encounter until the engine winds up. Higher stalls are used to let the engine engage at higher RPM when larger cams are used. Basically the larger the cam you use, the higher the stall the engine will want. When you use a big cam, you sacrifice idle and low end. Since the engine runs rough at those lower RPM's you want to wait to load up the engine until you get in the mid RPM range where the engine runs stronger. A lower stall engages earlier which gives less slippage. The weight of the car also effects the stall speed. A heavier car will stall higher with the same converter than a lighter car. A lock up converter "locks-up" at cruising speeds to eliminate slippage. They are shooting for 0% slippage. Regular converters have a small amount of slippage at driving speeds. Stock stalls for the 318 - 360 are probably around the 1500 - 2500 RPM range. I found one in a junkyard transmission off of a 360 2-bbl and had my trans guy test it when he rebuilt the trans for me. He said that it was in great shape and was better than the new/rebuilt ones. Sometimes older is better. |
#13
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The 268/272 cam is not really that big, and if you have around 9.2:1 to 9.5:1 compression you can use a fairly tight converter, possably 2,200-2,400 RPM stall and 3.23:1 gears?
If you want it to be really quick, but streetable go with a 10", 3,000+ Stall converter and 3.55:1 gears. I think Dynamic sells a street 10", 3,000+ stall converter for around $350? As a side note, if the cam/compression are mis-matched, too big a cam for the compression ratio, it hurts your low RPM torque and will require a looser converter. |
#14
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The 268/272 cam is not really that big, and if you have around 9.2:1 to 9.5:1 compression you can use a fairly tight converter, possably 2,200-2,400 RPM stall and 3.23:1 gears?
If you want it to be really quick, but streetable go with a 10", 3,000+ Stall converter and 3.55:1 gears. I think Dynamic sells a street 10", 3,000+ stall converter for around $350? As a side note, if the cam/compression are mis-matched, too big a cam for the compression ratio, it hurts your low RPM torque and will require a looser converter. You also should match the converter stall speed to your rear gearing to reduce converter slippage which creates excess transmission heat. Alaways use a transmission cooler with a high stall converter. |
#15
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Now that I understand what a stall converter is
doing, does running a higher RPM converter mean you will have more transmission wear? Will you need a tranny rebuild in a shorter time period than running a lower RPM converter? Similarly, suppose you run a 3500-RPM converter. and your highway RPM is roughly 2500-RPM. Are you running the risk of premature breakdown of any components to be cruising with the engine running below the stall speed? I am asking because it seems that it would be comparable to driving your standard down the highway with the clutch not fully dis/engaged. (Whichever terminology is correct on that.) |
#16
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Very good questions. First off whenever the stall speed goes up so does the heat involved since the energy that is not being transfered to the tranny is used up churning the oil around in the converter. Remember, the comparison to a slipping clutch is very accurate and what happens when you slip a clutch? Heat and burnout. This means that it is mandatory to have additional cooling capability, in the form of a cooler and if you have a deeper pan too, that is great as there is more oil to handle the heat.
If you ran the converter at the speeds suggested it would indeed raise the heat level since the converter has not reached coupling speed (above stall where the input and output of the converter is about the same speed). Lower rearend gears help (and often go hand in hand with a higher stall converter because BOTH say that the engine wants to be at a higher speed) because this raises engine RPM and gets you closer to coupling. This is why certain vehicles have a Lock Up converter and some don't- you will find the ones that don't have lower rear gears. In more extreme conditions I will also use synthetic oil since it won't break down or boil off like ATF can, at least not under proper operating conditions. |
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