7875 + 5.9 + E85 + Megasquirt

[turbovan]

Thanks. That kind of makes sense. So my converter that identifies as a 3.5k stall, deep down aspires to be a 6-6.5k rpm stall? Now I’m wondering how I would measure that gain if it’s still slipping a lot on its way up to 6k+ rpm’s? Food for thought anyway.

Not sure if you’re setup to log speed, but you could take it to 7k+ in 2nd gear and then calculate slip to see if it improves. Are you shifting into 3rd in the 8th? Assuming you’re slipping less than ~12% at 7k rpm that would give you 112mph in 2nd…if this calculator is correct.

Also just saw that it’s basically flashing to 6500. I thought it was 6k. I don’t see that converter working out for you either way.

 

[Turbosmblk]

Not sure if you’re setup to log speed, but you could take it to 7k+ in 2nd gear and then calculate slip to see if it improves. Are you shifting into 3rd in the 8th? Assuming you’re slipping less than ~12% at 7k rpm that would give you 112mph in 2nd…if this calculator is correct.

Also just saw that it’s basically flashing to 6500. I thought it was 6k. I don’t see that converter working out for you either way.

He can go to more gear too. A 4.10 should tighten it up 3-500. And leaving on minimal boost will help his 60’ exponentially. I went from 3.55 to 4.30 and picked up .1 to the 60’ with my stock motor deal on same boost. After I swapped cams though it’s become problematic as it has so much starting line ratio and making so much more power that it’s hard to tame.

 

[turbovan]

True this would also be an option, and 8 3/4 gears are pretty easy to swap, but then there’s a compromise to street driving with no overdrive. Either way, with more rpm or gear, he would just be chasing his tail since he plans to turn it up. I think a converter is the only real choice if staying 727.

 

[turbovan]

Also, subcom, I was looking back at the logs when you were trying to determine trans slip or converter. I remembered my dyno session when I had a broken rear clutch plate; bad trans slip on the dyno. It just pegged the limiter vs holding at an rpm like yours is.