Went to a dyno today. Mustang Dyno. Cool set up in Concord, CA.

Anyway, we're calibrating the RPM's @ 4000 in "D" (3rd gear). I'm holding the revs right there and then am asked to go to WOT and hit redline @ 5K. What happened is best shown with the attached graph (poor performance aside). To describe it in words however I would say that at WOT and with the resistence of the dyno, the car tried to drop to 2nd (or neutral?) at 4500 RPM thereby making it unable to complete the dyno runs.

What is this problem? The TV cable appears to be adjusted fine. I can say that the drive train itself prolly has all the original mileage (173K). It drives fine under normal conditions and is serviced yearly but I am afraid the age may be the factor here.

 

ya the only thing i can think of is.. well **** i dont know.. cant be wrong springs or weights or anything since it is the original transmission. i dont know how you feel doing this on the road, but start from a dead stop and floor it with the shifter left in Drive.. and see where it shifts at on its own from 1-2 and possible 2-3 (where it acts up on the dyno)

 

Do you think the corvette servo could be the cause of this? Seems like July is the month of stupid transmission

 

Oh no. I had this issue with the whacky downshifting before that. When we added that, the 1-2, 2-3 flare ups went away. Great improvement,

I'm thinking it is the age showing on the 700R4.

 

i wonder why didnt he at least run your car in second gear so you could know what your afr was.. or at least could have done the math later to figure out the true numbers if you were in 3rd gear.

 

Hey there Cad, pleasure to meet you for a min. at Dyno Day, too bad we didn't get to shoot the **** for a bit but hey I was fashionably late and 'ROC-less.

As to your problem I believe age is a contributing factor, but...

There is a product sold by B&M called the "WOT upshift kit" which is a different valve which connected to the end of your TV cable in the valve body of the trans.

P/N 70249 Catalog page link

Basically this valve corrects the set points in the valve body to downshift at over 50-75% throttle.

I remember the '87 GTA we used to own (5.7/700R4) and you could never be in D or OD and put your foot to the floor without the trans downshifting (from a roll).

You HAVE to know that "sweet spot" of not quite WOT but not downshifting. Yes I have raced many a Thirdgen, officer

In fact the new 'Vett Servo might just make this downshift more evident.

Just my Hope it helps

 

Wicked information.

How hard is this shift kit to install? What is the cost?

Thanks Vin!

 

That little kit shouldn't be much to install, you would basically have to drop the pan and the stock valve body to install that valve which lets you have WOT without downshifting like crazy.

If I was you, I would shop out getting a whole trans pro-built, that way you could get all of the modifications you want on it, and still have a car to drive.

Then you can set out a free weekend to do it right.

 

I need a buddy with good wrenching skills.

 

if you werent so far i would help . ask vin

 

I would do it mike but i hate trannys!!! And you have to take off your Valve body and im not a big fan of that. Sorry bro

 

you have an LO3... thos #'s are good..