Sorry, I can be a bit of a procrastinator sometimes so I couldn't help myself with the title haha.

All jokes aside, my questions are as follow..

I intend to keep my iroc as a streetcar that will see roadcourse racing as well as time at the strip. Will probably only do both a few times a yr at best. My transmission (700r4) is being rebuilt right now, and I'm putting a "stage three" (out of 4 stages) shift kit in it, a vette servo, and now I'm trying to figure out what's best to do with the converter. My dads trans shop is doing the work so price isn't an issue (other than cost of parts). I'm debating leaving stock converter or having them "rebuild" mine so it'll have a ~2000-2200 stall. What I'm looking for is when I'm at a stoplight I could let off the brake because of the converter, but I want the car to start rolling as soon as I touch the gas. I do NOT want to have to rev it to 2)+ before the car starts moving!

My engine is a stock 350tpi, but I will be rebuilding. Staying tpi, cam will come in around 1600ish. I want the converter to stall at 2000-2200 AFTER BUILD MOTOR.

Also debating this. I've read where people hook swtiches in the aldl to lock up converter on command. I'm interested in this, any thoughts on this? If I do this, would it be better to just leaave the converter stock?

Sorry for the long thread, and thank you for your input!

 

I wouldn't rebuild a stock converter to stall higher. There are a few reasons for that. 1) The clutches on the stock converter are small and thin. Not designed for higher stall. 2) The stock torque converter is 12". You can't get high performance out of 12" converters.

The stall speed is really only noticeable when you're "on it." People with 5000 RPM stalls will idle around the pits at 1500 RPM...... I've been in a Camaro with a 4200 stall and simply taking your foot off the brake pedal makes the car go forward just like a stock stall. With the 4200 stall, we were cruising down the streets at about 2000 RPM. Feather the throttle more and it went to 2500 RPM. Shift gears. It was only when you matted the gas, that the stall would fire up to 4200. And I mean RIGHT NOW it was at 4200. Sitting at a red light and then making a 90° left hand turn onto the side road, the time between pulling the car into the intersection (2000 RPM) and then being at 4000 RPM before even finishing the turn. (Slick tires help for situations like that.)

But even that is an extreme compared to what most of our cars are like. I would aim for a MINIMUM 2600 RPM stall. And most likely a 2800-3000 RPM stall.

Stall slippage is mostly a factor of drag on the car. Take a pickup truck with nothing in it and a 3000 stall. It might gently accelerate down the road at 2200 RPM. But take that same truck and tow a boat behind it and the RPM's will rise to 3000 RPM to maintain the same gentle acceleration. Cars with 2.73 axles are like towing a boat. While a car with a 4.10 axle won't slip nearly as much. Light cars vs heavy cars, same thing. This is why you can drive a daily driver car with a 3000 stall and for the most part it will drive like stock. It's only when you really press the gas pedal that it rises up (slips) to that higher RPM range. Hard acceleration is drag.

I wouldn't bother with having the ability to manually lock a converter. The converter is going to lock up by itself at around 45 mph. It will feel and act 100% like a stock converter after that (unless you mash the throttle to unlock it). People who drag race sometimes prefer being able to manually lock the converter near the end of the pass. But you need a triple disc $$$ converter to do that reliably. Not to mention lots of horsepower. We're talking running the quarter in the 11's.

 

I can't agree with that.
The single wet clutch in any stock converter is fully adequate for what it's there for, light-throttle cruising. Buying a "new" converter won't change that unless you're wasting a thousand dollars on one designed to lock at full throttle in hopes of half a tenth in the quarter mile.
Stall speed being noticeable depends on how tight the converter is, and how the axle is geared. Stock converters normally move along, when not locked, about 400-500 RPM above no-throttle, watching your tach. But try it with a 3200-stall, it'll be slipping about twice that much, and that is really a problem all the time, until you're just cruising with it locked up.
And the converter locking at 45 MPH is a real problem. It can and should lock by 35 MPH. If that causes your engine to lug, then your tune is off, or you need more axle ratio, or both.

 

Interesting, thanks for the good info guys. Now here's another question. I know some people swap in a 98 s10 4.6 2wd converter and it raises the stall to about 2000-2200. Any input on this? Is it a tight/loose converter? I'm 99% sure they're also 10in converters. (A side question, on a 300hp motor, how noticeable noticeable is the difference between a 10in and 12in converters?)
I'm tossing around the idea of getting a s10 conv.

For roadcourse racing, would a stock stall be better than a 2000-2200 stall?

 

The 4.3L S-10 converter is for fact not 10". 2.8L maybe, but 4.3 converters are around 12". And no, you can't try a 2.8 converter behind your 350.