Average RPM slippage on a conv
 

Whats the average rule of conv. slippage = in RPM +/- ? I'm trying to see what the top end RPM is with different rear gear ratio's .... RPM x tire dia. / by MPH X 336 = ring & pinion ratio . That formula dosen't account for conv. slippage , and is giving me the wrong gear ratios ....The car goes thru at 6750 x 28 tire / average 115 mph x 336 = 4:85 gear . But thats not true because it runs a 4:30 not a 4:85 . What would it go though with 4
:56 like 7150 rpm in average air ? My math / formula is wrong or I'm missing some thing .

Re: Average RPM slippage on a conv
 

Also if you have bias ply slicks you get some tire growth . Radials not so much .

Re: Average RPM slippage on a conv
 

Hard to put a number on slippage from this little info.....Converters vary
greatly. MY best advise is just trial and error if you do
not have a Data Monitoring System to fall back on.

Re: Average RPM slippage on a conv
 

115 x 4.30 x 336 / 28 = 5934 RPM (drive shaft RPM)


5934 x 100 = 593400 / 6750 = 87.9% (or 12.09% slippage)


115 x 4.56 x 336 / 28 = 6293 (drive shaft RPM)


6290 / .879 = 7159 RPM


The 4.56 gear should let the converter show better efficiency but, no way of knowing
exactly how much. Like was already stated, tire growth will affect the final number.

Re: Average RPM slippage on a conv
 

5% slippage is a good number to shoot for.

Re: Average RPM slippage on a conv
 

What if your % is 112?

Re: Average RPM slippage on a conv
 

you are slipping 12 %

Re: Average RPM slippage on a conv
 

Converter too loose????
I would have to double check but I think there is about a 1200 RPM drop between gear change(PG)

Re: Average RPM slippage on a conv
 

Ken, Ever try a 4.10 with that converter?

Re: Average RPM slippage on a conv
 

I have not tried the 410 gear yet . I need to try the lower 1st gear before I try the 410 . Its a low rpm torque combo mainly so I see your point Mark . Thanks