How much converter slip??
 

What %converter slip is normal for a STOCK Elm. car?

Re: How much converter slip??
 

It depends on the combination.

Re: How much converter slip??
 

396 325 hp 69 camaro

Re: How much converter slip??
 

An average car will see around 12-14%, maybe a little more. The problem is that they need stall to get off the line, but cannot pull enough gear on top and make enough RPM and HP to really lock up a converter and make it efficient.

Re: How much converter slip??
 

So I take it that if you have 8-10% you have a very efficient conv? I am speaking of a sb stocker. How do you determine the % correctly?

Robert

Re: How much converter slip??
 

Well, with a car that needs a ton of flash stall to get off the line good, but cannot turn a lot more RPM and make good power above that flash stall, yes, 8% is pretty good. That can be difficult with a lower HP stocker that doesn't turn a lot of RPM. If your finish line RPM is more than around 1500 RPM higher than your flash stall, and is also more than 800 RPM higher than your peak HP, it can be hard to get a converter to couple up really well.

Your finish line RPM and the MPH it should give, with your gear ratio and tire size, compared to your finish line MPH, will let you know about what your slippage is.

Of course, to do that, you are assuming the lights for the MPH clocks are set very accurately. That might be a big assumption, considering the variances you see in how well they are set of the starting line.

Re: How much converter slip??
 

Robert, to figure slip multiply your mph say 114 x gear ratio 5.13 x 336= 196499 then
divide by tire height 29.5 = gives you a rpm of 6661 then multiply by 1.08 for 8 % =7193.
just enter your correct values. mph x gear ratio x 336=@ then divide @ by tire height =true rpm with no slip and multiply by 1.08 for 8% 1.09 for 9% and so on to get your final rpm .

Re: How much converter slip??
 

what if you only come up with one or two percent slip.

Re: How much converter slip??
 

It's pretty rare to get below 4% to 5%, in most cases anyway. Check your math, and check your actual tire size.

Re: How much converter slip??
 

Most flogged out combos will have less than 5% slippage. Works on our car!

Re: How much converter slip??
 

The formula above is for radial tires, bias ply tires will grow, each manufacturer can
tell you approx how much at a given speed for any size tire. Like Alan stated each
car can vary in how much flash it will take to get it moving and how it will lock up on
the big end will depend on how much power and powerband width are available.
Most of the converter companies can get you really close if you give them accurate
info for hp, tq, weight,gearing and rpm potential. one other variable is where you race
sea level will differ greatly from altitude and so on. trial and error!!!! just my .02$

Re: How much converter slip??
 

I could be wrong, but if you record the engine RPM, and record the driveshaft RPM, assuming your in high gear and it's a 1:1 ratio, then the difference would be the converter slippage.

Re: How much converter slip??
 

In my SS car, according to the Racepak, 5% on a good run, 6% in poor air. Dyno

Re: How much converter slip??
 

Dyno

My race Pak is showing similar like 1 or 2% Just curious how you calculate the percentage of slip.

Just curious for comparision sake

Thanks
Don

Re: How much converter slip??
 

Using my ultimate 2 tach I came in at 3.5%.454 390 HP SS car

Re: How much converter slip??
 

Glenn, who makes these converters that you mentioned? You can pm me if you want to. Thanks

Robert

Re: How much converter slip??
 

Ron thanks for the info. At times it is hard to see 7000 or 7050, but I have gotten close. Ron, who do you recomend?

Robert

Re: How much converter slip??
 

Don, it will show in the Engine/DS ratio on your Racepak data. Check it at the end of the run.

Re: How much converter slip??
 

No secret Mike Munsinger is the man for torque convertors.

Re: How much converter slip??
 

Thanks Dyno

When I was looking at the Engine/DS ratio it is 1.073 I had assumed that was 7.3% slippage. However when I did the math Engine RPM 6134 D/S RPM 5715 I came up with 6.9%. Not trying to split hairs here just trying to understand the math.

Thanks Again
Don Turk

Re: How much converter slip??
 

Glenn, is he hard to get ahold of? I found a p# on line. Does he have a e-mail? I heard he is a one man show and is very hard to speak with get ahold of etc...Any info would be appreciated.

Re: How much converter slip??
 

Robert i have had good luck with ATI and PTC and i would like to try Lenny at ultimate he
is good to talk to. i just need to dyno my new cooker and get him the numbers.