High Stall Torque Converters

Spool said:

What about a 2800 stall...Ryan H pulled a 12.08 at pomona with this stall.

This may be more streetable...meaning the ability to launch well and actually *hook* with street tires. Not sure if the tires will blow up on even light gas, stalled launches with a 3800 stall?

Let me know what you think.

Click to expand...

Well, before I answer this I will first emphasize that a 4000rpm stall is VERY streetable on a MKIV.

Now if you are worried about traction with street tires, I really don't think street tires are gonna hold 400rwhp at BPU levels, with a any stall higher than stock. Hell, even with my stock converter I lit em up. The whole idea of the converter is to multiply torque to the wheels. If you are worried about traction on street tiires I think you are looking into the wrong mod. Technically speaking, will a 2800 spin the tires less so than a 3800stall? Of course, but it's not the optimum stall speed for the best launches with a proper setup. Optimum stall speed varies greatly with application but the general ruke of thumb for drag racing is 400-800 rpm's below peak torque. IMHO, in turbo applications you can get away with a bit less. Either way though, at BPU your stall needs to be at least 3800 (assuming you peak torque is probably around 4500rpm) to be optimal for launching the car, which is what the torque converter was designed to do in the first place.

I hope this helps.

I guess I wasn't clear enough about the question...

How much would you improve both drag & road coarse performance with a higher than stock stall:

1. From Stock 2200 to 2800

2. From 2800 to 3800


I understand regarding lighting up the tires, that's not the only factor...agreed, however, I do have intentions on road racing a bit.

So trying to solve two requirements:

1. Better Street racing launches....may need to get some DR's on full time but concerned about slickness in the rain/etc. Don't want too high of stall if the benefits do not offset the penalty to road racing/street/mountiain lower speed cornering.

2. Road racing - torque converters can help increase power on the road course in low speed cornering. However, too high of a stall may not be good??


So, in your opinion, would a lower than the "optimal" stall for drags be more suitable for my requirements?

Thanks,

Maury

Spool said:

I guess I wasn't clear enough about the question...

How much would you improve both drag & road coarse performance with a higher than stock stall:

1. From Stock 2200 to 2800

2. From 2800 to 3800

Click to expand...

This is impossible to say as it depends on so many other variables like tires, traction, track condition, driver, etc. Drag performance will continue to improve as your stall nears the optimum stall speed usually up to 400rpm below peak TQ. As to whether the improvement is linear or exponential, I do not know. I don't think anyone has tested enough stall speeds, especially on a MKIV, to demonstarte the improvments of raising your stall speed "x" amount. I do not know much about road courses as I have never been on one in this car. I also do not know the affects of converters on road courses. This is a tricky set of questions as it is extremely difficult to set a car up for both road racing and drag racing properly.

So trying to solve two requirements:

1. Better Street racing launches....may need to get some DR's on full time but concerned about slickness in the rain/etc. Don't want too high of stall if the benefits do not offset the penalty to road racing/street/mountiain lower speed cornering.

2. Road racing - torque converters can help increase power on the road course in low speed cornering. However, too high of a stall may not be good??


3. So, in your opinion, would a lower than the "optimal" stall for drags be more suitable for my requirements?

Thanks,

Maury

Click to expand...

Better street launches will be obtained, assuming you have traction, with a higher stall converter. As to whether the benefits offset the penalty for road racing, and as to at what stall speed the best compromise would take place, I don't think I can answer that. I'm not even sure that 3800 would be too high for road racing to begin with. I just don't know enough about the technical aspects of of where you would want TQ multiplied on a road course and how much would be too much. It may even vary between road courses.

Jc...

Are you running the stock twins in TTC mode? If so, how much boost off the line can you build when you power-brake the converter?

Also, what about low speed/RPM cornering....do you find that the higher stall keeps you in the boost? Is it controllable?

How is the drivability in your opinion?

Thanks,

Maury

jc said:

I have a 2800rpm art carr converter and it works fine
for me on the street. I think that a 3000rpm one
would work better for me since the trust fmic gave
me a little more lag.

peace,
jc

Click to expand...

Maury,
i still have the stock peashooters in the sequential mode.
The driveability is good.
Haven't had any problems with it at all.
The trans cooler is a must too.
Before the stall i raced a friend that has a mildly built
355 in his camaro with 4.11 gears and he would
smoke me off the line and i would reel him
in about half track.
We all changed the converter in my hotrod and went
back to the spot and ran them again.
It woke up the launch nicely.
If i remember correctly from going to the track,
my 60ft times went down a couple or few tenths.
I think it would have been more if i had a greddy
side mount intercooler.
Hope it helps somewhat.

Peace,
jc

jc,


Yes, that helps.

Are you able to beat the Camaro off the line with the high stall?

How much boost can you build off the line? Just curious.

I may go with a 3000 stall.

Maury

First off,

You will not need a tranny until you go single or blow it up on the stock twins.

So, until then, the only thing you would loose is about $400 in labor to install the TC. What you would gain is about 1/2 sec off the 1/4 mile times and way better launches.

The TC slips like a clutch. So a 3800 stall conveter will be like a 3800 rpm launch as you are slipping the clutch with a 6spd....keeps you at higher torque, so you make more power and launch better.

The computer locks up the tranny itself, however, it's not 100% locked. So a lockup switch will allow you to eliminate any slipping. This is done in 3rd to eliminate damage to the tranny...the gearing in 3rd is nearly 1:1...so it's not harsh on the TC or tranny.

That's it!

Pooshda: You're Welcome!

Here's my dilema...if you cannot tell from the posts.

Under light throttle, the car will start to move right away, however, a bit slower than the stock stall speed of 2200RPM. So you'll hear the engine reving more as it gets going. That's not a problem though, just a charateristic.

But, if you punch it, the motor will rev to the stall speed. It's weird at first because you're giving it gas and the car is not moving. Then, when the RPM hits the stall speed, the TC starts hooking! If you have crappy street tires and puch it with a 3800 stall....you will sit in one place and roast the tires!!!!

I'm looking to get a lower stall, to cut down on tire wear and maintain some of of the streetability of the stock stall. However, I do not want to sacrifice too much of the lauchability of a higher stall TC.


That's why I've asked JC a few more Q's regarding his 2800 stall.

I am also going to drive Ryan H.'s car here locally. He has a 2800 stall and is in TTC mode....he pulled a 12.08 at pomona 1/4 track with no fuel tuning and stock MAF. So basically he can be in the 11's very easily. That's what I'm looking for!!

Later.