Torque converter slippage

Makinchips · 03-15-2019, 12:01 PM

What percentage does an 8" a/sa or b/sa converter slip approx.

I'm considering upping the rear gear in my bracket car which runs low 10s presently but am unsure of the rpm gain from converter slip.

Alan Roehrich · 03-16-2019, 09:28 AM

We get 4%-6% with an 8" ATI.

Dan Fahey · 03-17-2019, 02:12 PM

Quote:

Originally Posted by Alan Roehrich

We get 4%-6% with an 8" ATI.

How about 10 inch? I need a stall of 5000 - 5600 for my Impala SS

gsa612 · 03-17-2019, 03:27 PM

Quote:

Originally Posted by Dan Fahey

How about 10 inch? I need a stall of 5000 - 5600 for my Impala SS

How are you going to get that stall from a 10" converter with low hp?. gsa612

gmonde · 03-17-2019, 08:20 PM

Quote:

Originally Posted by Dan Fahey

How about 10 inch? I need a stall of 5000 - 5600 for my Impala SS

you would be hard pressed to get that from a 9"
8" is the area ,, tune the converter from there

STK1217 · 03-17-2019, 08:41 PM

ATI told me as much as 9% for a PG 8" 5800 rpm 1.76 first gear 3200 lb. 509 BBC 800 hp was not uncommon.

Dan Fahey · 03-17-2019, 10:50 PM

Quote:

Originally Posted by gmonde

you would be hard pressed to get that from a 9"
8" is the area ,, tune the converter from there

Thanks...my car is a 1995 Impala SS LT1.
Weight 4150 lbs, stock rods, limited to about 7000 rpm.
Trying to understand the latest generation of converters.

Determining best gear to chose for top end.
5% slippage more gear, 8% slippage less gear.

D

Mike Pearson · 03-18-2019, 01:50 PM

Quote:

Originally Posted by Dan Fahey

Thanks...my car is a 1995 Impala SS LT1.
Weight 4150 lbs, stock rods, limited to about 7000 rpm.
Trying to understand the latest generation of converters.

Determining best gear to chose for top end.
5% slippage more gear, 8% slippage less gear.

D

Dan
The more gear that you have in the car the less the converter will slip. Talk to ATI about your combo and they will get you in the ballpark on the first try. Then you can make some changes as you move forward and test the car. Talk to Charlie at ATI. He is real familiar with the class racing stuff. You really can’t go wrong with them.

Mike Rietow · 03-18-2019, 09:58 PM

Quote:

Originally Posted by Makinchips

What percentage does an 8" a/sa or b/sa converter slip approx.

I'm considering upping the rear gear in my bracket car which runs low 10s presently but am unsure of the rpm gain from converter slip.

There is an equation. Need this info.

Tire size + observed roll out? + bias or radial?

Current gear

New gear

The current rpm and mph at the stripe.

It'll tell exactly what rpm you'll cross with the new gear , as well, as converter slip percentage with the current and new gear.

03-15-2019, 12:01 PM	#1
Makinchips Junior Member Join Date: Apr 2016 Posts: 26 Likes: 0 Liked 3 Times in 3 Posts	Torque converter slippage What percentage does an 8" a/sa or b/sa converter slip approx. I'm considering upping the rear gear in my bracket car which runs low 10s presently but am unsure of the rpm gain from converter slip.

03-16-2019, 09:28 AM	#2
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,115 Likes: 1,572 Liked 1,829 Times in 414 Posts	Re: Torque converter slippage We get 4%-6% with an 8" ATI. __________________ Alan Roehrich 212A G/S

03-17-2019, 08:41 PM	#6
STK1217 Member Join Date: Nov 2006 Posts: 137 Likes: 48 Liked 10 Times in 7 Posts	Re: Torque converter slippage ATI told me as much as 9% for a PG 8" 5800 rpm 1.76 first gear 3200 lb. 509 BBC 800 hp was not uncommon. Last edited by STK1217; 03-17-2019 at 08:46 PM.