smokedbytt

I'm hoping someone here has some insight...I had some mods done on my car about 3-4 months ago (larger turbos, exhaust/manifold, ECU, intakes, suspension, wheels). I decided to have it dynoed.

There's a 4 wheel dyno down here called Twilight....they never dynoed a Porsche and that should have been my big clue. My car is tiptronic. I know for a fact that my car is at or over low 500's to the wheels because of other cars I have raced. On the first dyno run the car acted kind of strange...it went through 3rd gear, redlined and then automatically switched to fourth ....abs and psm faults then a strange smell....almost like trans fluid. The dyno came in at 403hp to the wheels. On the second pull the front wheels were noticeably slower than the rear (more than they should be). The smell was getting stronger and I stopped half way through.

After that the car began slipping while shifting from 3rd-4th gear while under power. Once in 4th it was fine but it would take a second or two to catch and start to pull.

The transmission control unit was replaced but didn't fix the problem. Next, a new transmission was put in but still didn't fix the problem....and now here I am. Do you have any idea what it could be? A friend has told me it sounds like the differential. Could it be the upgraded ECU?

Help!

TT Surgeon

It's the front differential, you have to disconnect the diveshafts if you're going to dyno it w/ awd. The PSM really makes the porsche act differently on a dyno esp w/ awd and a tip.
I saw in another thread that you can't dyno a tip anyway, Kirby might have some insight to this.
Chris

Moogle

sounds like he made a huge mistake... terrible

Kevin

You most likely knocked out the front diff.. You can't put a TT on a 4wheel drive dyno without knowing if the the dyno is mechanically linked.. I have pictures of Sharky's car with a cracked diff after his dyno run.. When in doubt disconnect the driveshaft like Chris mentioned.

What brand Dyno was it...

Moogle

He mentoined it was called a "Twilight" ?

Kevin

Is Twilight the dyno shop or the name of the dyno?

sharkster

Yeps I did this a long long time ago. You will now need a new differential as it's done for. A little bit of variation from rear to front because the dyno wasn't mechanically linked causes the front to diff to heat up really fast and just pop. I cracked the case almost all the way around and lost three teeth. Diff fluid went everywhere obviously. Not a good situation I'm afraid

I don't care what dyno operators say in terms of "Our software is so well calibrated to the nearest single RPM etc..." because unless it's mechanically linked I'm never ever ever taking the risk again.

smokedbytt

You guys are awesome.....you have made my week.

I have been back and forth from the dealer (luckily I'm friends w/ the mech) for almost a month now. The trans was just finished yesterday and when that didn't do it I was sick.

The dyno is a "Dynojet," Twighlight performance is the shop - located in beautiful Hialeah, FL. Do I have any recourse w/ them?

I'll let you know what happens....but thanks again. Chris

BartN (TX)

Is this repair being covered under warranty or is it your tab?

Geoffrey

I have dynoed an AWD 996tt with manual transmission on both Dynapack and Dyno Dynamics dynos with no issues. Neither of these is mechanically link, however are designed for the 996 style AWD system. The electronic aids must be turned off though.

ebaker

Is it OK to run on a 4WD dyno if the front and rear rollers are linked mechanically?

Geoffrey

Yes, for example a Mustang dyno is mechanically linked by belts.

Kevin

Guys, if you don't want to risk yor drivetrain.. Un-hook your driveshaft.. The last shootout that was held, all drive-shafts were disconnected... The previous one was on the Mustang and everything was left intact... For the record, TIP's won't dyno... The transmission will uncouple, and upshift...

To date the only dyno's that I have seen that will work on our cars without damage are:

Mustang
Dynopak


Feel free to add to the list if one is successful.. (first hand knowledge)

Kevin

Alex, post the picture of your diff...

smokedbytt

warranty...thank god
New diff will go in on mon/tues