I know a guy around here that goes to a local college and he is in their automotive program. It just so happens that they have a dyno AND are looking for some cars to put on it! So basically I get some free dyno pulls I remember hearing that there is something you can disconnect under the hood to keep the car from downshifting out of third gear when you are doing a pull. Am I making this up or is there something I can do?

John

 

well, you could always get it at 1500 rpm in 4th and it will kick it down into 3rd when you hit it. There's no real good way to dyno below 3000 rpm for an auto.


You COULD change the downshift values in the pcm if you can program that.

 

Never heard of that one. Automatics are dyno'd in 3rd, so as long as it's in third it shouldn't shift.

But my trans is a 4L60 non-electronic...

Anyone else wanna help this lucky guy out?

 

No, the problem is it downshifting into 2nd.

John, there are two fixes. What I do is reflash with LT1 edit to a program that has the upshifts and downshifts at really low MPH, so at 2500 rpm it will not downshift into 2nd. I can get a really good tq reading that way.

Since you don't have programming capability at this point, the only solution is to get rpms above the kick-down speed. Run it up to 75 mph before you hammer it and it should be ok, if not you'll have to try 80.

It shortens the RPM range your graph will show but there's not much you can do about it short of programming.

 

Oh well, musta got confused. I think someone called it a kickdown sensor or something........ Maybe it is only for older cars.

Thanks guys for all the help, I'll wait till the speedo hits 80 and then hit it. With the PCMforless tune it will still drop to second at 75.

 

F.M.V.

 

What's that? It's too early to think here, only 8:00 am