Last spring I bought a SP 400 from PAE. Its got the heavy duty sprag and that stuff. (I'm not a trans guy). I also got one of his fancy 11" high stall s/p converters. Its marked 4200 which is the high stall and low stall is supposed to be around 1800 to 1900. I bought this with intentions of going into the 10's with my 1989 Turbo Trans AM (the TA with the GN turbo V6 motor). I hurt my motor last year at the Nationals in BG. I then decided to build a Full Stage 2 motor for the car. In cake walk mode the motor should be able to make 800 HP and in kill mode it should do 1100 to 1200 HP. Now heres my delema: How much power can a s/p converter take? I dont want a TC explosion taking my legs off. Can a s/p converter and trans be ran safely and will they work properly at these power levels. The torque of this motor should be very high also, probably 800 to 1000. If this set up isn't proven at these levels is any one interested in it? I bought it last spring. Got the car running the day before the nats. Drove about 15 miles on the street, made 2 partial passes in BG and the car has been parked since. Jim at PAE recommended that I run a certain Caterpillar drive train oil in the tranny, and thats what I put in it. I live in central Illinois, I'am a GSCA member, and I have around 1000 posts on the turbobuick.com board (I'm postal on that board also). If any one has some feed back for me and/or is interested in this set up please contact me, or post a reply. Jason Loftus postal@mchsi.com 309-253-7991
Jason, I don't think the SP can stand up to power levels like that, I might be wrong. Be that as it may, you are better off with a fixed pitch converter with the proper stall speed. The car will be more consistant, and the fixed pitch converter will be lighter. The SP is an awesome street transmission, but it sounds like you'll be mostly racin with that combo.
They way I understand it is that the vanes move and change angles in the s/p converter. I would think that when going from high to low that the vanes would have to fight against the power of the motor. I'm thinking the vanes may stay stuck in high stall mode under that much power. I'm leaning more and more towards selling this set up. I will be in BG for the Nationals. If any one wanted the set up I could bring it there, so there would be no shipping expense. Jason
Jason, I believe it is just the opposite. Fluid flow in the converter forces the stator blades back to the low stall position, over 4000 RPM I would get a good fixed pitch converter matched to the engine specs. You get what you pay for in converters. If you can afford a converter like a Coan, you'll never look back. I love my switch pitch, it's great on the street, but you need a fixed pitch setup with a Stage2 motor at those power levels.
We have had one behind a twin turboed small block chevy making over 1200 horsepower for about 8 or 9 years. He finally broke a pump. Refreshened him up a converter and got him going again. I would recommend an ultra bell bell housing for that kind of power.. Jim Burek
