My buddy has a big block and his tranmission guy says lower stall for drag racing.
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My buddy has a big block and his tranmission guy says lower stall for drag racing.
Hey LT1 guys help me understand something. I am tired of argueing with my buddy. But his tranmission guy says that a lower stall is better for drag racing because you don't want a loose stall because you are losing horsepower. My buddy's engine makes 500lbs of torque at 2500rpms and 600lbs of torque at 4400rpms at the flywheel. The tranmission guy says he needs a 2500 stall. Why would he say this for drag racing? Wouldn't he want close to a 4000 stall. Am I right or is the transmission guy right?
Last edited by djm_e22; 05-15-2010 at 08:29 PM.
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That is exactly what I told him. Now I have heard that the higher the stall the more slip. For example a 2000 stall slips maybe at 5% at the 2000rpms and higher and the 4000 stall may slip at 7% at 4000 and higher. But I don't think that would be enough to lose the race.
#4
It really depends on how much tq the engine makes and where (rpm), what gears are in the car, what size and type of tire and how much the car weighs. A big block makes so much more tq than a sm block so it can use less converter and leave just as hard. You want the converter to stall near peak engine tq for an all out drag car but on a dual purpose car with stock type suspension too much converter and the car will be lazy during daily driving.
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It really depends on how much tq the engine makes and where (rpm), what gears are in the car, what size and type of tire and how much the car weighs. A big block makes so much more tq than a sm block so it can use less converter and leave just as hard. You want the converter to stall near peak engine tq for an all out drag car but on a dual purpose car with stock type suspension too much converter and the car will be lazy during daily driving.
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It really depends on how much tq the engine makes and where (rpm), what gears are in the car, what size and type of tire and how much the car weighs. A big block makes so much more tq than a sm block so it can use less converter and leave just as hard. You want the converter to stall near peak engine tq for an all out drag car but on a dual purpose car with stock type suspension too much converter and the car will be lazy during daily driving.
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X2, but I think 2500 is too low a stall unless he is trying to make his passes on street tires....which would make NO sense with a 600 ft lb big block. Also, keep in mind that a convertor rated at 2500 is going to stall up more behind a high tq motor like his. Maybe that is what the trans guy is trying to say?? Either way, I don't see a typical 2500 conv stalling up anywhere near his 4000 rpm peak.
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Quicker vs. Faster
I didn't catch that. LOL Funny thing is I spent 30 min trying to explain the difference to my kids the other day. I told them my SS is FASTER than my 61, but the 61 would blow it's doors off in a drag race. They still don't get it.
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im not sure id agree with that... the motor would probably fall back on the higher stall converter during the shifts, higher stall is probably alot smaller and lighter, etc. you dont really see a 2500 stall for racing use, unless we're talking about a cummins or duramax. this transmission guy... i wouldnt spend my money with him
#13
Smallblock rules don't always apply to big blocks, and even then every build is different.
Usually, you want around 500rpm stall rating below peak tq for drag racing, and a 4k may on paper seem like the best bet when bench racing...but who here thinks they can hook 600ft lbs of tq flashing off the line??? Without a crazy drag setup, that's not gonna happen.
He may have a BBC, but it could be a street rod, and could very well end up quicker in the 1/4 with a 2500 stall.
Like stated, it depends on his gears, weight, cam, etc. If someone told me MY build would be quicker with a 2500 stall, then I wouldn't let them even wash my car, let alone work on it .
Usually, you want around 500rpm stall rating below peak tq for drag racing, and a 4k may on paper seem like the best bet when bench racing...but who here thinks they can hook 600ft lbs of tq flashing off the line??? Without a crazy drag setup, that's not gonna happen.
He may have a BBC, but it could be a street rod, and could very well end up quicker in the 1/4 with a 2500 stall.
Like stated, it depends on his gears, weight, cam, etc. If someone told me MY build would be quicker with a 2500 stall, then I wouldn't let them even wash my car, let alone work on it .
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Smallblock rules don't always apply to big blocks, and even then every build is different.
Usually, you want around 500rpm stall rating below peak tq for drag racing, and a 4k may on paper seem like the best bet when bench racing...but who here thinks they can hook 600ft lbs of tq flashing off the line??? Without a crazy drag setup, that's not gonna happen.
He may have a BBC, but it could be a street rod, and could very well end up quicker in the 1/4 with a 2500 stall.
Like stated, it depends on his gears, weight, cam, etc. If someone told me MY build would be quicker with a 2500 stall, then I wouldn't let them even wash my car, let alone work on it .
Usually, you want around 500rpm stall rating below peak tq for drag racing, and a 4k may on paper seem like the best bet when bench racing...but who here thinks they can hook 600ft lbs of tq flashing off the line??? Without a crazy drag setup, that's not gonna happen.
He may have a BBC, but it could be a street rod, and could very well end up quicker in the 1/4 with a 2500 stall.
Like stated, it depends on his gears, weight, cam, etc. If someone told me MY build would be quicker with a 2500 stall, then I wouldn't let them even wash my car, let alone work on it .
Last edited by djm_e22; 05-15-2010 at 08:52 PM.
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I don't know why they are saying that because first off that my buddy's engine is 600lbs of torque at the flywheel. By the time it goes through his th400 and 9" it will be in the mid 400 most likely. He will be using slicks. Also the transmission guy never said about him not getting traction. Matter of fact the tranmission guy assumed he would get traction because he said the higher stall will just get you a better start but you will lose at the end of the track. So can anyone now explain why he would say this or is he just simply wrong?
#17
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I don't know why they are saying that because first off that my buddy's engine is 600lbs of torque at the flywheel. By the time it goes through his th400 and 9" it will be in the mid 400 most likely. He will be using slicks. Also the transmission guy never said about him not getting traction. Matter of fact the tranmission guy assumed he would get traction because he said the higher stall will just get you a better start but you will lose at the end of the track. So can anyone now explain why he would say this or is he just simply wrong?
higher stall = faster launch, slower acceleration
lower stall = slower launch, faster acceleration
#19
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It doesn't make sense that a looser converter that slips more, but lets you launch closer to the peak of the power band would result in a lower e/t, but also lower trap? That lower trap wouldn't just magically happen, so would the car not have to accelerate slower AFTER leaving the line?