Can a 993 Twin Turbo safely run on a Dyno in 4WD ?

[DaveMiddleton]

I want to dyno my newly boght 993 Twin Turbo. The Scottish company who own the 4WD dyno have raised a point that they THINK Porsche do not recommend running the 993 in 4 wheel drive on rollers.
Any knowledgeable people out there please?

[iguana]

Generally accepted as no, well not if you don't want to feck up your front dif, won't take long to disconect tho.

[GuyR]

I think the general view is that unless the rollers are mechanically linked, it can put some strain on the transfer box.

However, I'm sure it would be OK for a single power-run.

Ask G-Force, who dyno tons of Porsche 993s and 996s and they certainly don't remove the front driveshaft before doing so............

Guy

[BarryJ]

I’m going to take my 993TT to the rolling road day at G-Force. See:

www.pistonheads.com/gassing/topic.asp?t=92845&f=48&h=0

...and I checked with them as to what happens with the 4WD. They said that its only the 993TT that needs to be disconnected. Later or earlier models don't need to be disconnected.

[iguana]

GuyR said:

However, I'm sure it would be OK for a single power-run. Ask G-Force, who dyno tons of Porsche 993s and 996s and they certainly don't remove the front driveshaft before doing so............ Guy

Guy no chance on earth I would run a 993T if it were mine without disconecting the front dif.

Strangely a modded 993T ive driven that had a knackered front dif had been run on the G force rollers.....

BarryJ said:

I’m going to take my 993TT to the rolling road day at G-Force. See: Later or earlier models don't need to be disconnected.

Well earlier turbos than 993 are all 2wd so not a problem 964C4 fine to keep connected tho.

Generally accepted 996 is fine to run as 4wd although some gearbox issues have been known, so some do suggest if you are running big power, it might be advantagious to run it as 2wd.

[GuyR]

I guess thats because a 964 4wd has a fixed mechanical linkage, with no clutch based variable transfer box?

Obviously the 996 must use a different/stronger transfer system than a 993 then as well given what GF say.

I always used to run my Skylines in 4wd and never had any problems with the transfer-box (which is a multi-plate clutch).

Guy

[phelix]

> ...and I checked with them as to what happens with the
> 4WD. They said that its only the 993TT that needs to
> be disconnected. Later or earlier models don't need
> to be disconnected.

Umm, am I missing something here? G Force has an AWD rolling road but to test a 993tt it's necessary to disconnect the front drive shaft?

[ian_dorrian]

Little worried about this as my 993 C4S is due at G force on the same day and I assume my sheep in wolf's clothing has the same running gear as the 993tt.

I really don't fancy a big bill for the sake of a simple power test...



Is it a mare of nocturnal proportions to disconnect the drive shaft to the front wheels or something altogether straightforward?

Ian D

[BarryJ]

phelix said:

> Umm, am I missing something here? G Force has an AWD rolling road but to test a 993tt it's necessary to disconnect the front drive shaft?

Correct; I’m no specialist but just relaying what G-Force told me. I guess it shouldn’t make any difference because the rolling road is testing the power coming from the engine and therefore it will be the same coming from 2 or 4 wheels.

ian_dorrian said:

I really don't fancy a big bill for the sake of a simple power test... Is it a mare of nocturnal proportions to disconnect the drive shaft to the front wheels or something altogether straightforward?

I asked this question and they told me that it is relatively straightforward and since we are bringing several cars, they would do it at no extra cost. It would be a good idea if you also called G-Force and checked with them so that there are two of us that have been told this just in case someone tries to charge us extra on the day. I spoke to someone called Chris who was extremely helpful.

[aceparts_com]

I've just spoken to Chris - very helpful chap, and he said he will disconnect the 993 turbo drive shafts to save them from being destroyed.
All 993 4WD owners need to be there ealier for this as it takes about 30 minutes each way. There will be no extra charge providing 20 cars in total turn up.

Alan

[ian_dorrian]

Excellent, I will be there very early!

Really looking forward to the day although I hope the GF 1800hp dyno can measure as low as my target 285bhp...