Oldguard 7

Happy 4th everyone. I have purchased a voodoo series cam 276/284 with a rpm range of 2200-6400 rpm. My heads, compression ratio, carb, and intake are a match with this cam (did the research) The advertisement states "likes 2800 stall convertor" My concern is the torque convertor which leads to my question. How many rpms above the low end of the cam's power band should I go? I have 3.55 gears which is a happy medium. I'm thinking I should get a convertor with a stall speed range up to 2800 rpm as a 3000 stall would generate too much heat. Opinions please.

427Hotrod

A lot depends on how much power the motor actually puts out, weight of the car, gearing...and what you want to really do with it. For max acceleration typically you want the converter to flash to right at or above PEAK TQ...which is likely to be in the 4000+ RPM range depending on what else you have. TQ converters have come a long way and you can have a converter that flashes like that yet still locks up well with little slip at the top end. That won't be one of the $99 specials..but if you deal with folks like ATI and others you can get what you need. Best to call them directly because there are very subtle changes thay can make that will make a huge difference vs buying a *universal* converter.

JIM

gingerbreadman1977

is this a th350 cause thats important to know. if it is at 60 you should be cruising at about 3200 rpm with 355 rear gears . a 3000 stall should be fine if thats the case. i would base my decision on if you want maximum launch then go the 3000 or if your going to do a fair amount of cruising then go something lower . also a 3000 stall is always alot more expensive than a 2500 .

gkull

Modern high stall TC's have minimal slip and generate lots of heat. I had a 6500 stall TC and it was no problem driving from the pits to the staging lane and on the return road to the pits. The return road here is 15 mph and I had to ride the brake to keep from exceeding the speed limit at idle. It wasn't slipping.

Vigilante TC's are $700, but worth every penny. I drove my Vette for 2 years and probably 20,000 miles without a lockup with 9.5 inch 3500 stall

Bee Jay

I recently blew up two torque converters and needed a good, high quality, high performance, affordable torque converter. The guys over on the C4 forum rant and rave and swear by a converter by Pete K. We exchanged a few emails and I bought a 2500rpm stall 9 1/2" lockup converter for $500 shipped to me. It's warrantied for one year, and if I break it after one year, he rebuilds it for $100. I also get one free stall change within one year. If 2500 is too much or too little, I just send it back. I've had my car back for only one week but so far so good. Not too noticable difference from my 2000rpm stall 10 1/2" lockup stock Corvette converter. It takes a little more gas pulling from the red light, and when you switch on the lockup, there is a larger drop in rpm. I've only launched on it twice so far but holy smokes, it's sh*tin' and gettin'. I pulled up to a four way stop with the wife today and some idiot couldn't decide weather to go or wait for me to go. I gave it the usual amount of gas when I want to get thru an intersection quick, about 1/4 throttle, and the car chirped and launched like I just robbed a bank. My wife asked "what was that?" I told her I was still getting used to this new torque converter. She really wasn't interested. But go over to the C4 forum and search Pete K and torque converters. I'm a happy customer.
Bee Jay

Pete K

Sounds like alot of fun. I am glad to see you are back in the saddle, and enjoying the ride.

Tim H

Buy a tight 3000 stall from PTCrace.com in Alabama.
Call then and tell them your set up and they will send you a 10inch converter that will kick AZZ!!!

ajrothm

Custom built converters are the way to go for sure...>Especially as cheap as you can get them these days..... more stall speed, better torque multiplication, better driveability and efficiency.....

EVERY C3 can use more stall speed....even a stock 350 will see a .5 reduction in ET with a properly matched converter.....You're leaving power on the table if you're not running one.

96 lt-4

A tight 3000 stall will be fine.Just make sure you run an auxillary trans cooler.If you do more stoplight driving it may be a bit more than needed.
That cam will like a true 3000 stall when you hammer it.Save up for some back tires.

Tim H

Yes find somewhere for a cooler, It doesnt have to be the high priced one either just the finned ones like maybe 12X8.

Bee Jay

Thanks Pete K. It's been over a month of driving and one autocross event, so I have a few more observations.
The biggest difference I've noticed is the speed at which the engine will rev up and then back down. I had my 5 speed Porsche flywheel lightened once, and it's the same effect. The 9" torque converter revs up and back down so much quicker than the much heavier 10.5" converter. The fuel injection will actually let the engine stall if it isn't totally warmed up yet.
It takes a little getting used to when you are headed down the highway in non-lockup mode. The engine will free wheel a little more when you lift or apply throttle. But when you come to a hill with the lockup off, the engine is immediately off idle and into the powerband. You actually look forward to hills or long grades. It's like downshifting into third but your still in fourth.
Also, if you are traction limited like I am, you will waste a set of tires quickly. If I give it any agressive throttle from a stop, the rear end lights up. Burning rubber is now effortless, maybe too effortless. I could not get the rear end to hook up at the last autocross event. The fast time of the day was taken by a lower horsepower all wheel drive Subaru. Maybe Chevy will make all wheel drive available with the C7 ZR1. Now that would be something.
Like I said before, it was a pleasure dealing with Pete K. and I have not managed to break his converter. I might go with even a lower stall if I had it to do over again because I rarely need a drag strip style launch, but I do need to ease away from stop signs and lights.
Bee Jay