torque convertor % slip

i have a coan super mega convertor and 3 speed lenco shift 9500rpm .convertor slip 0.05 % before shift and at the end of track i would like to know how your convertor slip if its secret pm me thank you Eric

 

I'm about 7% with a 10" trans specialties when going 6.50 210. I don't understand how you have 5% before the shift. You reading off a Racepak graph?



Greg www.MotorSportsInnovations.com

 

BBC running 6.50 @ 212, Coan Super Glide XST and Coan Bolt togeather converter. High gear at end of 1/4 my slip rate is less than 1%.

Steve

 

Slip %

To be accurate we had to install input sensor on the lenco drive. Alot of things effect the slip such as tuneup , track, gear ratios, chassis setup. It is hard to compare with others. But here is one. 4.25 1/8th 169 mph 2700lb 500 brad 38lbs @8000 3 speed lenco drive with Chance 10" 2.03/1.41/1.0. 5.7% before shift (8400). 18.4% after shift (7550). 10.5% at 1/8th (8000). I have seen .5% to 0 before the shift with Transmission Specialities custom cad converter and 3 to 4 % at the 1/8th.

 

Lockup ?

Has anyone tried the Hughes lockup converter, or something similar?

 

around same set up 4.46 1/8th 163mph 2770lb 456 brad 3.900stroke 35lbs@9500 3speed lenco 1.90/1.48/1.0 4.88rear gear but below 1% at 1/8
you prefert chance or transmission specialities with 4%

 

4% in 1/4 mile with Coan 280mm; less slip is great but if the car isn't accelerating it's just a number to look at. A truly efficient converter cannot be gotten to less than 3% or so. If you have less than that you can go quicker with more slippage. In the pic shown here the engine rpm is nearly flat, that is not good. Also why is the car shifting so early in the run?

Brandon Booher
NHRA TAD #34

 

Iron468, I think most converter companies can make a good converter. Buying from one that is familiar with your setup is best. My preference is Trans Specialities because we have dealt with them a long time and use alot of their products. Depending on how you race your car a converter that tightens up with rpm could make it hard to get through the shift. It could hit the tire too hard.

 

68 lbs. fuel pressure at 7500 rpm ?

 

If you don't have it, I'd strongly recommend a flow-meter on your Racepak.

Brandon Booher
NHRA TAD #34

 

Engine goes flat around 7500rpm anytime I try to quick/fast (6.80's = bracket mode - 650's = fast mode). I'm assuming it's valve springs. I'm only 280 on the seat with stainless valves. The early shift is just a low RPM shift - 7000.

Agree completely with your thinking that tight slippage numbers are not necessarily good.

Greg www.MotorSportsInnovations.com