converter slippage

sg5985 · 10-04-2010, 10:31 PM

What is a reasonable amount of converter slippage for a 2100 lb SG car running 1/4 mile?

Dave Steltz · 10-05-2010, 08:38 AM

Mine is 2400 lbs, runs 9.90 @ 152, have two convertors, a Greg Slack unit and also a spragless, slip is between 6 and 7%...

nickh · 10-05-2010, 01:15 PM

The converter manufacturer can build in any amount of slippage that you would want. For instance Hughes will take all you information they will custom build (Greg Slack will too) a converter to your setup. Hughes will give you one free tweak in the converter once you have run it to get it closer to your liking. 4 - 8% slippage is the general. Hope this helps.

sg5985 · 10-05-2010, 04:46 PM

so if you're running, 152 mph with 6-7% slip, you have to be set up for a theoretical mph of 163 mph?

Dave Steltz · 10-05-2010, 08:18 PM

Not sure what you mean by that....I measure convertor slip with my data recorder....Engine RPM at the stripe vs driveshaft speed, divide the two and there ya go...

I guess I may have more mph if it slipped less, or the engine might not have enough hp to pull more....

sg5985 · 10-05-2010, 10:39 PM

OK, so for example 7200 RPM, 4.30 gear, 32" tire theoretically is 160 - 163 mph so 7% slippage would give you about 152 mph @ 7200 RPM.

My converter is slipping a little too much but my mph is way down from where it should be based on hp/weight. My combination is 2140 lb roadster / 680hp / 4.56 gear / 32" tire and I'm barely running 139 mph at the stripe @ 7100 RPM. Too low a gear maybe?

Thanks for the input.

voltdr · 10-06-2010, 09:13 AM

Quote:

Originally Posted by sg5985

OK, so for example 7200 RPM, 4.30 gear, 32" tire theoretically is 160 - 163 mph so 7% slippage would give you about 152 mph @ 7200 RPM.

My converter is slipping a little too much but my mph is way down from where it should be based on hp/weight. My combination is 2140 lb roadster / 680hp / 4.56 gear / 32" tire and I'm barely running 139 mph at the stripe @ 7100 RPM. Too low a gear maybe?

Thanks for the input.

I have never seen the charts be very accurate. Maybe the chart has less wind drag than your car. Maybe the issue with the formula is the stated HP. Try using a different Hp in the formula to see match your actual MPH.

Charlie Yannetti · 10-06-2010, 10:13 AM

Voltdr.. you hit it on the head.. both Dave and I are in Street Roadsters.. the charts say that I should be in that 160 to 163 range, but the body style just won't allow it.. Dave's car might be a little bit more slippery than my aero 27, but not much..

Tom Goldman · 10-06-2010, 05:39 PM

Could the problem be in your #? .....Div. 5 tracks can be pretty high in altitude if memory serves correctly = less HP ........converter slippage can make you nuts ,my current converter has 10% slippage @7600rpm and I still run 162. .....same engine with a 9" @4% slip 160 @ 7200, it never let the motor get up in its power band.....................sounds like you need some more dective work.................Tom

sg5985 · 10-06-2010, 11:15 PM

Thanks for the input. It sounds like the converter may be OK but I may not be geared tall enough. I might have to change out the 4.56 gear for a 4.30 and see if it'll pull the extra gear.

Tom, the tracks around here are 800 - 1500 feet but when we go a little further west we can get into some serious elevation. I know some guys have got high elevation tune ups, but I'm having enough of a challenge putting together 1 good local tune up!

10-04-2010, 10:31 PM	#1
sg5985 Junior Member Join Date: Jan 2010 Posts: 16 Likes: 0 Liked 0 Times in 0 Posts	converter slippage What is a reasonable amount of converter slippage for a 2100 lb SG car running 1/4 mile?

10-05-2010, 08:38 AM	#2
Dave Steltz Member Join Date: Nov 2003 Posts: 323 Likes: 0 Liked 0 Times in 0 Posts	Re: converter slippage Mine is 2400 lbs, runs 9.90 @ 152, have two convertors, a Greg Slack unit and also a spragless, slip is between 6 and 7%... __________________ Dave Steltz 135G SG/SP/SST BIAECH Racing Team

10-05-2010, 01:15 PM	#3
nickh Senior Member Join Date: Sep 2010 Location: Houston,Texas Posts: 819 Likes: 3,511 Liked 642 Times in 192 Posts	Re: converter slippage The converter manufacturer can build in any amount of slippage that you would want. For instance Hughes will take all you information they will custom build (Greg Slack will too) a converter to your setup. Hughes will give you one free tweak in the converter once you have run it to get it closer to your liking. 4 - 8% slippage is the general. Hope this helps.

10-05-2010, 04:46 PM	#4
sg5985 Junior Member Join Date: Jan 2010 Posts: 16 Likes: 0 Liked 0 Times in 0 Posts	Re: converter slippage so if you're running, 152 mph with 6-7% slip, you have to be set up for a theoretical mph of 163 mph?

10-05-2010, 08:18 PM	#5
Dave Steltz Member Join Date: Nov 2003 Posts: 323 Likes: 0 Liked 0 Times in 0 Posts	Re: converter slippage Not sure what you mean by that....I measure convertor slip with my data recorder....Engine RPM at the stripe vs driveshaft speed, divide the two and there ya go... I guess I may have more mph if it slipped less, or the engine might not have enough hp to pull more.... __________________ Dave Steltz 135G SG/SP/SST BIAECH Racing Team

10-05-2010, 10:39 PM	#6
sg5985 Junior Member Join Date: Jan 2010 Posts: 16 Likes: 0 Liked 0 Times in 0 Posts	Re: converter slippage OK, so for example 7200 RPM, 4.30 gear, 32" tire theoretically is 160 - 163 mph so 7% slippage would give you about 152 mph @ 7200 RPM. My converter is slipping a little too much but my mph is way down from where it should be based on hp/weight. My combination is 2140 lb roadster / 680hp / 4.56 gear / 32" tire and I'm barely running 139 mph at the stripe @ 7100 RPM. Too low a gear maybe? Thanks for the input.

10-06-2010, 10:13 AM	#8
Charlie Yannetti Senior Member Join Date: Jan 2005 Location: Alpine, NJ Posts: 568 Likes: 188 Liked 192 Times in 83 Posts	Re: converter slippage Voltdr.. you hit it on the head.. both Dave and I are in Street Roadsters.. the charts say that I should be in that 160 to 163 range, but the body style just won't allow it.. Dave's car might be a little bit more slippery than my aero 27, but not much..

10-06-2010, 05:39 PM	#9
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,474 Likes: 885 Liked 859 Times in 234 Posts	Re: converter slippage Could the problem be in your #? .....Div. 5 tracks can be pretty high in altitude if memory serves correctly = less HP ........converter slippage can make you nuts ,my current converter has 10% slippage @7600rpm and I still run 162. .....same engine with a 9" @4% slip 160 @ 7200, it never let the motor get up in its power band.....................sounds like you need some more dective work.................Tom __________________ Tom Goldman 1500 SG , 1506 STK

10-06-2010, 11:15 PM	#10
sg5985 Junior Member Join Date: Jan 2010 Posts: 16 Likes: 0 Liked 0 Times in 0 Posts	Re: converter slippage Thanks for the input. It sounds like the converter may be OK but I may not be geared tall enough. I might have to change out the 4.56 gear for a 4.30 and see if it'll pull the extra gear. Tom, the tracks around here are 800 - 1500 feet but when we go a little further west we can get into some serious elevation. I know some guys have got high elevation tune ups, but I'm having enough of a challenge putting together 1 good local tune up!