I bought a torque converter and it states 3000 stall. I have a few questions.

1) Is the car still supposed to move forward at idle (approximately 900 rpm)?

2) When holding my foot on the break is the car supposed to load the suspension at 1800 rpm?

3) When increasing the rpm in gear with my foot on the brake at about what rpm should the tires start to break loose? I understand this depends on the tire and such but a range would work.

4) does the torque converter need time to break in to the correct stall speed?

I am thinking the torque converter is too low of stall speed.

Thanks,
Chas

 

Probably so.
A 3000 RPM stall should have relatively little hookup at 1800.
Yes.
No.

You should be able to stand on the brakes, and slowly push the gas down; and the highest RPM you see should be somewhat close to the "rated" stall speed of the converter. This is far from a "scientific", "accurate", legally admissible in a court of law kind of test; but should somewhat ballpark the stall speed IN YOUR COMBO. Which, looking at what you've got, your converter will be at the stall speed about 110% of the time, except at the strip; I'd recommend a REALLY REALLY REALLY BIG trans cooler. You can make up for not enough gear, with stall; but when you have a gear like THAT, the drive train RPM is NEVER going to be high enough for the converter to be fully engaged.

Also, you tend to get, AT BEST, what you pay for, in converters. It takes time to make one really GOOD, and time = money in this universe. If you pay the least, you get, AT BEST, .... I'll let you do the rest of the math.

IROC (the late International Race Of Champions exhibition series) has (had) no hyphen in its initials. Please fix your signature. It's embarrassing.

 

I have a 6000 rpm stall converter in my race car. I can drive around the pits at an idle. Stall speed is when the converter is in 1:1 ratio with the turbine turning the same speed as the impeller. Any rpm below the stall speed and the converter is slipping. Slipping builds heat so any converter higher than stock needs some sort of aftermarket tranny cooler.

There are too many factors to try and find the converter's stall speed without using a transbrake. You'll never hold the car back with the foot brake while coming up on the converter. The tires will always brake free before you hit the stall speed. Flashing the converter is the best way to find the stall speed but it takes lots of practice to understand what you're looking for and the number will never be 100% accurate.

With a transbrake, the transmission is locked in first and reverse. The engine rpm can come right up to the converter's stall speed without the vehicle moving. This allows for quicker launches at the dragstrip. At the higher launch rpm, when the transbrake is released, the reverse circuit fluid is dumped and the car launches forward in first gear.

How much stall speed you need depends on the cam grind. Too high a stall speed can be just as bad as too low. The purpose of the higher stall speed is to get the engine into it's powerband quicker at WOT for best performance.

The converter rating is also just a rough estimate. An identical converter behind a BBC will stall higher than one behind a SBC because of how much torque is being put into it.

 

1) yes, it never completely disengages

2) yes, it will engage more and more as RPMs increase

3) anything above 3k should grab

4) no


watch this

 

Thanks guys I had been reading contradicting things all over so I figured I would ask and get my facts straight.

I cant believe I never caught that hyphen in my signature.