Ridin Dirty

I have a long winding driveway uphill to my home about the length of a football field. Kinda cool way to arrive at home....a nice hill climb before I tuck her to bed.

When my VC was down she fishtailed on the "hill climb" around the corners (kinda predictably fun with the kids in the back) Fixed the VC...no more fish tail...and I mean nuthin. BIG difference.

Joe

Macster

At a Porsche dealer the other day. Talked to the tech about dyno testing these AWD cars. (I have a 996 Turbo.) and mentioned your situation.

He said if you directed the dyno operator to disconnect the belt that connects the rear rollers to the front to see how much rear wheel HP the car produces this is on your head. (The techs said often the owner requests this not knowing the ramifications are of this.)

If the dyno operator disconnected the belt for whatever reason the shop is responsible for the damage.

It just happens there was a 993 Turbo in one of the service bays in for a ruined VC. Seems the car broke down -- I do not know what the initial problem was -- and the tow truck operator insisted on towing the car in on its rear wheels only.

The owner, a woman, tried to tell the tow truck operator the car should not be towed that way but she got the standard BS response from the operator something to the effect he's towed lots of Porsches before and he knows what he's doing blah blah blah.

So, rather than escalate the confrontation the owner let the tow truck operator have his way.

Well, of course, by the time the car got to the dealer the VC would in pieces. It just came apart.

Tech estimated cost to repair roughly $3K. He said the tow truck company was picking up the bill.

OverBoosted28

NO tow truck operator is gonna tell me how the car will be towed. The driver has to be a complete idiot to look at the car and say he's gonna drag it from the front. Even at stock height the tips should have scraped. Crazy

They should also throw in a pain/suffering amount.

owen meany

Thank you Macster for that info.
I did not ask for the belt to be removed. The shop had removed it in order to be able to do 2 wheel drive cars as well as some other AWD cars.
I feel the same as the dealer explained.
Thank you.

Macster

When I heard this I thought how the heck did the exhaust tips and in fact the rear of the car not sustain any damage from the front wheels in the air tow?

Anyhow, unfortunately, tow truck drivers are often complete idiots. They manage ok as long as they are dealing with vanilla vehicles but toss something like an AWD Porsche at them and well, they are out of their depth.

I pity the woman owner. She I'm sure tried to convince the tow truck operator to do the tow correctly but got overruled, shouted down, and maybe a bit physically intimidated by the operator.

Once or twice I've had an encounter with a tow truck operator, a disagreement about how to handle the car, that I felt had I pushed it we could have come to blows.

For instance, tow truck operators all insist on using the tow eye to hold the car on the truck. This has the eye sustaining load not in direct line with the long axis of the eye and its bolt and which the owners manual says it should not be subjected to.

But I can't get any tow truck operator to disconnect the line from the eye once the car is on the bed and secured by hold downs.

I object but get overruled -- unless I want to duke it out with the tow truck operator and I don't -- so I bank on the fact that the eye and where it secures to the car is over engineered and no real harm will happen.

Macster

Then in my layman's opinion the shop is at fault and should pay to have the car properly repaired.

Bernie930

Once again what Rennsport Steve said, the belt has to be Disconnected, on roller dynos. I have seen my fair share of blown VC on high HP cars but not from dyno damage. Also from dyno the wrong way though. But what came first? The chicken or the egg, lol.Just saying.

ca993twin

Many years ago, a small group of 993TT owners went to a "dyno day" at a shop in inland SoCal. One after another, we saw the front wheels stop spinning after the first dyno run. It finally occurred to us that all those viscous couplers were being trashed by a 4WD dyno that didn't have a "driven" front roller. Luckily, I was last in line, and declined my dyno run. The shop was setup for WRX AWD dyno runs.

Macster

I think you should reread what Rennsport Steve wrote. He wrote the driveshaft should be disconnected.

Here I'll save you the trouble of searching out his post:

"For me, I ALWAYS disconnect the front driveshaft when running these cars on a roller-type dyno, no matter what kind it is: Dynojet, Mustang, Superflow, etc. The only exceptions are the wheel hub style such as Dynapack, etc."

This is a bit of work to protect the VC and the rest of the front drivetrain when dyno-ing the car but perhaps worth the peace of mind.

But the peace of mind one gains on the one hand is countered by the concern I would have about doing this disconnect. That is, I am not up on if any fasteners can be reused or instead should be replaced but I would familiarize myself with the correct procedure for disconnecting then reconnecting the front drive shaft.

If the car is put on the dyno the wrong direction that is the fault of the dyno operator.

It boils down to the dyno operator owes you a reasonable level of skill, experience, and caution in what is to be done. It is not like you have a dyno and are pulling a stranger off the street to operate it for you. You are seeking out a shop that offers this service. If your car is accepted then the shop is making a contract with you that essentially says it knows what it is doing,and it is selling its ability to apply this knowledge to accomplish what you want, and you of course agree to pay for this.

Frankly, based on what I've read, the horror stories, I would no more dyno either of my Porsches than I'd drive them through an Afghan mine field.

In fact given the choice, dyno or mine field, I'd ask how big is the mine field.

DM993tt

Dyno is a pretty good way to know how much power your mods make....

http://youtu.be/wy2_rNMc6xw

Slate993tt

Nice....527rwhp. You're car must feel fantastic! Is that the new motor? Sorry to take the thread a bit off-topic.

DM993tt

...Well its the same case and crank, but most of everything else is new. I had to send out the ecu to get it re-programmed for the new components. It leaned out as boost came on under WOT. That pull was in 3rd and it was getting wheelspin on the dyno. They had to re-calibrate for 4th gear. It makes a silly amount of power - and that was at 1.1bar boost. I'll be putting it back on the dyno when I get the ecu back.

owen meany

That's a ton of power. My one run before damage showed 438 (?) rwhp and a bit more than that for torque. The shop confirmed that it's the viscous coupler. $1200 on the part from Porsche and about $3500 on labor. I didn't realize the coupler was in the trans. I was thinking that the Diff in front was the coupler. Not so. Lot's of labor getting the coupler out and back in. The shop also feels like it's obviously the dyno shops responsibility. I have no previous relationship with this shop so I feel as though it's a good professional opinion.
Thank you everybody for your responses and thoughts. We can let this thread go now unless someone has any other questions.

ScottMellor

$3500 for labor?
I was the dude Steve was talking about who trashed a VC on the dyno a few years ago.
My tech swapped it out in about an hour and a half.

Pry

My tech said it can't be done without dropping the engine so decided to do it with a friend of mine. Took us first timers a damn lot more than an hour and a half but still managed to do it without dropping the engine and saved me a lot of money.