Okay. I've always have had manuals in my corrvettes. Well I bought a 77. Now the question is, does the 3500 stall hit it's max torque at 3500? And are you supposed to brake torque it to 3500 rpms at a stop to get the best out performance out of the whole? If i take off out of the whole just by stomping it to the floor. It just spins the wheels for ever. It's a 383S. I've read about it but it still doesn't make sense to me.

Thanks. John

 

A 3500 stall - in basic terms - means the converter will allow the engine to flash to 3500 at which time it locks up and goes. That said, the actual stall rpm may vary depending on the engine combo behind it and also will flash and begin to move the car sooner if you throttle it gradually and sneak up on the converter. The theory IS to match the stall to the max torque rpm of the motor, or just below, to get the hardest launch when racing. A "loose" converter also helps when you run a wild cam as you typically need to idle it at a higher rpm and a tight stock converter will have the car creeping or will cause the motor and tranny to fight, making it difficult to sit at an idle wile in gear.

If you are using a 3500 stall on the street, it's a LOT of stall and of course you'll sit and spin, as you are applying max torque to the wheels and your tires and traction are the weak link. You either need stickier tires and more traction, or less converter to allow the car to move and hook up earlier instead of simply shocking the tires, and yes you can brake-stand somewhere below the stall speed and then let it go for a hard launch.

It is probably an awesome combo at the track under sticky conditions. If you have too much stall and do primarily street driving, you could replace the converter with a tighter one - say 1800-2500 - which would help drive ability.

 

Thanks Joe. I understand it perfectly now. I guess that I need some new tires. But I don't know what the widest tire that I can put on, with out them rubbing the springs or fender well.

 

sometimes the consequence to adding stickier and/or wider tires behind a lot of HP and high stall converters , is usually broken OEM driveline parts... like U-joints , spindles etc..

 

If your cruising rpm is less than your stall rpm you're going to have severe transmission overheating problems unless you have a locking torque converter.

 

Not completely true. I run a 3K stall w/o issues. But a tranny cooler helps.

 

This is exactly true. It is a vicious circle. Add traction and break parts. On a street car sometimes it's best to keep the tires as your weak link.

 

So I guess that I need a transmission cooler. Because at 70 MPH I'm at 3000 rpms?

 

you live in Northern Michigan? Bring your car down to the Louisiana coast on an 112* August afternoon in slow traffic with that sloppy T/C.. ... your transmission will not last long in this heat ..you will need either a locking converter and or an Auxilliary cooler

 

Thanks Joe. I think that I'll put a cooler on it anyway. I might drive it to Tennessee this summer. 6-8 miles to the gallon. LoL can't hurt.

John.

 

Anytime you have increased performance and a higher stall torque converter it is a good idea to put a trans cooler on it.

A quality modern high stall torque converter doesn't act near as loose in normal driving as converters of years gone by. Put a cooler on and you will be fine.

Mike

 

A cooler is cheap easy to install, and great insurance from overheating.. anyone with a performance car should use one.. I ve been to Tennessee many times.. have friends in Chattanooga.. great places to drive a Corvette there. Besides gas is only $2.00/gal down here

 

V2 is right, the converters of today are vastly more efficient than units of years ago.I run a 9" 2800 Stahl I live in florida have a big champion radiator and it seems to be keeping my fluid cool enough without a cooler.the lighter mass. Of this converter makes the car snappier. I asked FTI to build it so it wasn't too slippy for lack of a better term and they nailed it. Drag radials became a necessity as it would just boil the tires before I got this converter. I haven't broken anything so far although I have custom half shafts and solid joints.you just need to make sure you have well maintained components and you will be fine. These rears are a little tougher than people give them credit.

 

Well maybe I'm okay then. The trans only has about 800 miles on it. Totally bulit new. Maybe not to worry then. Got to go about 2000 thousand miles.

 

And all new U joints and it's real tight.

Thanks
John

 

that is not a true statement for quality efficient TC's. On a level freeway at 75 mph my 9.5 inch 3800 stall would only change 100-200 rpm if I hit the lockup switch

 

sure... problem is, THATS not when it builds heart.. at cruising RPM TC is about 95% efficient..no issue....BUT its at 1200-1400 idling in traffic on a hot day, that the issue.. its SLIPS , causing friction and heat... you cannot deny that.. its made to slip at lower rpm.. that why you get good idle with big cams.. Do you have a Trans Temp gauge? mine never exceeds 175* in worst heat ..I have a cooler

 

It has been often said a standard non-locking torque converter with a 1200 to 1300 rpm stall is about 97% efficient at cruising speeds of say 2500 rpm. But when you use a 3500 rpm stall torque converter at engine speeds of say 1500 to 1600 rpm it has a tremendous amount of internal slippage which generates massive amounts of heat. I personally would never recommend using anything over a 2000 rpm stall for a street driven C3. I chose a 2000 rpm stall for my 454"/TH700R4/3.70 because the stock torque converter wouldn't allow a low enough idle rpm with my 236/236 degree Magnum camshaft. Yes, you can manually shift your automatic to keep the revs high but that's a real pain in stop-and-go city traffic. The only place high stall torque converters have any real benefit is for drag racing where you need to bring the engine rpm up high enough to get into the cam's power band for a harder launch.

 

don't put out bad information. It is obvious that you don't have high quality anything in the way of parts. So don't quote about things that you don't have any knowledge of

from experience I recommend stalls of 1/2 of the intended red line number. But I only build roller cam motors and the TC'S are $800-$1500 each. I blew out the lockup multiple clutch behind my 7500 rpm 427 solid roller motor. I drove it 15,000 miles over 2-3 yars and never saw tranny temps get high

if you know anything about 700r4s. The tranny case brass cooler line adapters are reducers to 3/8th. So you can install 1/2 inch adapters and 1/2 inch steel braided custom lines. The biggest B&M coolers are also 1/2. In and out

 

I don t want to get in the middle of you two going at it, BUT.....heres my thought. You may have one , but I seriously doubt the OP has a $1500 Converter.. more likely a $300 one ... and with 3500 Stall, its gonna be sloppy at low rpm and produce heat.. that's just reality ... But by all means tell him he doesn t need it at all, because your High End custom built T/C works on your set up .. A $100 cooler makes a lot more sense than a $3000 Trans rebuild to me... just my opinion...