Just looking at my dyno sheets and calculated converter slip of near 12% at 126 MPH and 6% at 150 MPH. This is assuming no growth of the 31.5" slicks. If there was 1" of growth, then the 126 MPH slippage was 14+%. 126 is my typical trap speed. What should I expect from a converter?

This is a PI vig multi disc, but I don't lock at WOT.

 

It is easier to do in terms of engine rpm.

At >6000rpm I want it to be <10% slip, with slip % being (trans input speed)/(engine rpm)

I had a converter that was roughly 15% and after I had it tightened it was around 8% and I gained 3-4mph in the 1/8th with no other changes, which at my weight was roughly 150hp.

 

Yes...couldn't recall the exact RPM. Forgot that I had posted the sheets here. 5690 at 126, 6360 at 150. What I wasn't thinking was that the dyno was in 3rd. So trapping in second, I will be around 6400.

 

Doing none 1:1 gears takes a little more work, but I would still compare trans input rpm to engine rpm, it doesnt matter what the vehicle speed is.

 

At 6700 my PI converter is at 4% slip. I took it to 6900 last week but messed up and forgot to save the scan so don’t know what it was then.

 

Throw those numbers out the window. Not only are the numbers fudged a bit due to not having an actual driveshaft speed sensor, but trying to calculate based on engine rpm seen on the dyno is a waist. The motor will be loaded up a ton more when it is actually travelling 125 mph.

Once you can get some solid data, either by getting a driveshaft sensor or at the very least using data from an actual pass, you can make a better decision on what the truck will need.

A very good turbo converter will be on lock down through the traps, say 2-5 % unlocked. Where as procharged stuff likes it a little looser, say around 8-12%. Given that your blowers don't need engine rpm to build boost, I'd treat it like an N/A or turbo set up and guess that tighter is better for you.