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Discussion Starter #1
Need some advice on High Stall Converter, what do you guys have on your cars? What kind of numbers does it produce? What do you guys recommend? Worth it?........I'm listening, thanks. :D

Danny
 
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3800 Precision Industries

It can drop your ET substantially as long as you have a lock-up switch.

I recommend a 3800-4000 stall converter for most MKIV applications includding BPU and small-medium singles.

Well worth it. You won't regret it at all.
 

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Supreme, do you know of anywhere on the net that tells you how to wire in the lockup switch?

Also, did you say you lock your's in near the end of 2nd or right after it shifts into 3rd?

thanks
 

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If your running in the mid 12's with a BPU automatic Supra, what would a high stall converter drop that to on average?
 
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Discussion Starter #5 (Edited)
swamibob said:
Supreme, do you know of anywhere on the net that tells you how to wire in the lockup switch?

Also, did you say you lock your's in near the end of 2nd or right after it shifts into 3rd?

thanks
No, but you can call SP and ask Larry. I believe supratt96 has instructions as well if you can find him. Chris at PM in Austin did mine and he probably knows as well. His handle is PM supra.

IThe top of 3rd is acceptabl but the end of 2nd is ideal. The earlier you lock it up the more you stress the converter lock-up plates. PI recommends top of 3rd.
 
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Discussion Starter #6
KJSUPRA said:
If your running in the mid 12's with a BPU automatic Supra, what would a high stall converter drop that to on average?
Well, asuming you could pull a 1.8-2.0 60' without the converter, I think a 1.6 60' is definitely within reason with one. That's going to end up being about 4-6 1/10ths at the end of the 1/4 as long as you can lock it up.
 

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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.
 
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Discussion Starter #8
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.
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.
 

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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
 
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Discussion Starter #10
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
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
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.
 

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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
 

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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
 

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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

 

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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
 

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Forgive my lack of knowledge, but how does a lock up switch work exactly.. im still a little hazey about the whole torque converter thing... I keep hearing "lock up at the top of 3rd, 2nd" whatever.. what exactly does that mean?

Im slowly trying to learn all of these things... because right now I dont know everything I need to know, and I dont want to just go blindly modifying my car until I know exactly which way is best to go about it... Also, is a high staul TC just fine with the Automatic tranny?

I had been putting off getting a TC until I had the money for the SP transmission as well.. just seems like I should do it all at once to save me money in the long run, and the downtime of the car... any info would be appreciated :)
 

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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!
 

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oh cool as hell.. thanks for the info, I have a better understanding of it now :) ... Yea I think maybe Ill get a TC and throw it on over the winter when downtime for the car isnt a problem anyway... if I do it over the winter I will be able to take it to my friends shop and we can do it ourselves since there will be no rush.. I wont take the dawg in the snow anyway :D

Thanks for the info, It helped :)
 

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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.
 

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Maury, if you are even remotely considering going single in the future, get the 3800 stall now. I have a 3200 stall, and it isn't enough to get my car to launch really well (SP63) without using nitrous. I'll be taking my tranny off again this winter to put in a 3800 stall. :(
 

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hmm... that seems strange... even if im not launching the car and Im just driving it normally... I need to wait for 3k for the car to start going?... what if im at a light and im turning, if I need to hit 3000+ rpm before actually turning im gonna smoke the fuck out of my tires and slide sideways around the turn I would think.. that seems a little crazy...

But I still think im probably a little hazey on the understanding.. If my car isnt going to move until 3800rpm in everyday driving that seems a bit extreme... and Ill be spinning my tires on accident all the time, or Ill look like a little punk drifting around every turn I take... Hopefully im just taking it the wrong way.. I hope thats not how its gonna be ALL the time.. that would suck =|
 
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