Car is in sig, dyno'd at 299rwhp at ~4800rpm and 351ft lbs at 3600rpms. This was with a pretty bad header leak, but its still a good idea of where the car is at I think. Engine was just rebuilt. Where should I be shifting at for the most power?

 

With the M6 it will probably take some time and experimenting (several runs w/ documentation) at the track to figure-out the best shift point for each different gear.

For bracket racing, the A4 (4L60E) w/ the programmed shift points is a nice option to work with and very consistent once everything is programmed correctly.

WD

 

Rough estimate based on what you see? Haven't been to the track yet, hope to have DRs and a tune before I take it out. But I'm curious with the numbers I have right now where I should shift to get the most out of the car.

 

Did the hp peak at 4800rpms? That seems too low to me. A general rule of thumb is 500 rpm past peak hp although if it drops off drasticly then you wouldn't want to go that far past.

 

When I started racing I first shifted at 5400rpms and made several passes to make sure the results were consistent. I then went to 5600 and then to 5800and on my car at that time 5800 was the proper shift point for me as performance dropped off at 6000. After experimenting for several weeks I actually found the 1-2 shift was better at 5600, and the 2-3 shift at 5800(I was running 1/8 mile at the time). You need to take into account all aspects of the run, including the shallow or deep stage, weather, track conditions, engine and transmission temps, and driver consistency to accurately measure the results at each rpm point. The object is to be "perfect" with each shift instead of thinking you are on a great pass so you try to jam it a bit quicker or let it go an extra hundred rpm or so...

With consistent and clean powershifts you should hgain no more than 200rpms during each powershift point (it takes much practice unless you are somehow naturally gifted) but when you become proficient it can allow an exceptional driver to become extremely consistent and actually compete (sometimes) with automatics.

 

bone stock with 3.23's i shifted out of first at 62 or so, and 58-60 on every other, resulted in consistent high 13's

 

i shifted at 2850 on the shiftlight and went time in sig

edit: that was with some bolt ons and 4.10s

 

Only 2850 RPM, about half the potential RPM range? I wonder how fast it would go shifting around 5800??

WD

 

If you have dyno numbers, it's easy to calculate where the power to the wheels drops below where it would be in the next gear (i.e. the optimum shift point). All you need are dyno numbers and the tranny gear ratios. there are also some on-line calculators to to do this, though I can't seem to find the links at the moment. As a rule of thumb though, which is good if the gear ratios aren't really screwy, it's best to shift a couple hundred rpm past peak hp.

Rich

 

doh! i meant 5850 my apologies

 

Now that makes much more sense.

WD