996 C2 rear wheel hp ?

996 C2 rear wheel hp ?

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Thom

Original Poster:

2,745 posts

286 months

Wednesday 25th June 2003
quotequote all
What would the rear wheels power output be for a 300 or 320 bhp engine ?

AJLintern

4,279 posts

276 months

Wednesday 25th June 2003
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Isn't it usually about 15% less than flywheel? So maybe 255-272 BHP?

Thom

Original Poster:

2,745 posts

286 months

Wednesday 25th June 2003
quotequote all
If so then a simple 250hp 944 turbo with a £200 Guru Racing kit is more powerful (and lighter) :



I've driven such a car, it's AWESOME.
To sum it up, it drives like :
- a 944S2/968 between 2000 and 3000 rpm
- a stock 951 250bhp on full boost between 3000 and 4000 rpm
- a rocket from 4000 rpm up to the redline.

I need one

ninemeister

1,146 posts

271 months

Wednesday 25th June 2003
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Most 996 3.4s struggle to post more than 250bhp at the wheels whereas a good 964RS with 290 flywheel will post 265+ at the wheels. But if you think the 996 is poor we have also tested a few 2.5 Boxsters at just 165 @ wheels.

Every car is different, there is no point trying to assign % losses between models as there are too many factors affecting performance, like tyres, tyre pressure, gearbox, gearbox oil and temperatures.

Thom

Original Poster:

2,745 posts

286 months

Wednesday 25th June 2003
quotequote all
Colin,

I was not trying to make any serious point except that I find interesting that a more than 10 years-old Porsche with minimum budget can offer a significantly better power/weight ratio than a brand new one.

In other words, no need to take my words with a grain of salt

>> Edited by Thom on Wednesday 25th June 12:32

ninemeister

1,146 posts

271 months

Wednesday 25th June 2003
quotequote all
Thom,
You must be feeling guilty today, my post was a general one and in no way specifically directed at your comments or power figures for the 944 Turbo (which seems impressive, it has to be said). It's just that I get a little fed up with assumptions about power losses and the like, every car is different, every dyno is different, but in general as long as the dyno is accurate the rear wheel power figures are generally the uncorrected on-the-day result, so as such are a pretty useful comparison as they can not lie.

AJLintern

4,279 posts

276 months

Wednesday 25th June 2003
quotequote all
Thats why I put a question mark after my assumption rather than stating it as fact

diver944

1,846 posts

289 months

Thursday 26th June 2003
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Thom, is this the Guru $290 chips plus Reliaboost option? 285bhp and 338 lbft at the wheels seems very high for such a reasonable outlay, are you sure that graph isn't showing the figures at the flywheel?

Even if it is, it seems like good value because most rolling road remaps here in the UK talk about 280-90 bhp at the flywheel for a £450ish cost.

Hsve you been in this car or seen that graph in another forum somewhere?

Cheers,

Paul

kevinday

12,895 posts

293 months

Thursday 26th June 2003
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I would think that the figures shown in the graph are indeed flywheel figures, not at the rear wheels. In my experience most RR operators give you a graph showing the 'corrected' figures. Corrected is in quote marks because they are really a estimate, not factual.

Thom

Original Poster:

2,745 posts

286 months

Thursday 26th June 2003
quotequote all
diver944 said:
Thom, is this the Guru $290 chips plus Reliaboost option? 285bhp and 338 lbft at the wheels seems very high for such a reasonable outlay, are you sure that graph isn't showing the figures at the flywheel? Have you been in this car or seen that graph in another forum somewhere?




Yes, that's the kit. I assume these figures are measured at the rear wheels : before being in and trying the car of my friend I went in a genuine 300bhp Turbo but the car with the GR kit feels significantly faster, even though it is a road car with a 300lbs weight handicap compared to the Cup.

The graphs do not come from my friend's car but judging from the power & torque delivery compared to that of the Cup I would say this engine gets out more power than the Cup's 300bhp, thus validating to a certain extent the graph I posted below.

edited to add : boost is the same as on the Cup at 1.1 bar (16 psi).

>> Edited by Thom on Thursday 26th June 09:51

diver944

1,846 posts

289 months

Monday 7th July 2003
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Well Thom, I've spent the last few weeks reading a lot about GuruRacing.net on Rennlist and a few other Porsche Forums. All the feedback has been good, and I have exchanged a few emails with the owner Danno which has also given me a good feeling

So..........tonight I just ordered his chips and Reliaboost for $290 US. After import taxes and VAT it should work out at around £250 GB. I had been looking at a Dual Port Wastegate and a rolling road remap here in the UK for a total of £1000, but if this 1/4 price alternative gets me close to the 300bhp that the expensive option would have yielded then I will be happy. I'll keep you informed.

Thom

Original Poster:

2,745 posts

286 months

Monday 7th July 2003
quotequote all
I'm pretty sure you will be pleased with the improvement.
Please make sure your engine & turbo are fine before installing the kit; the increase in performance is so impressive you may at first wonder if the engine can be capable of bearing it ...
(The engine of my friend has 240,000 kms but also a brand new head)

>> Edited by Thom on Monday 7th July 16:34

diver944

1,846 posts

289 months

Saturday 12th July 2003
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Thanks for the warning Thom. I'm only at 97k miles but I had a leakdown and compression test last year and all seems fine on that front. Speaking to many 944T owners with raised boost it seems to be the head gasket that goes first but the Turbocharger is basically sound. If it does go then that is perfect excuse for an uprated version that spools up quicker but provides a bit more boost. I'll get my wallet

The GuruRacing stuff should have shipped yesterday

Thom

Original Poster:

2,745 posts

286 months

Saturday 12th July 2003
quotequote all
You are welcome Paul, please keep me informed on how you get on !