Porsche Dyno Day video

[kj911]

Hi all,

Sorry for anyone who has spotted the corss-post to the Porsche forum; thought Id flick this up here for those who may not check that forum

Here is a short video of the recent Porsche Club Dyno Day in Auckland. The video includes a 996 with X50 kit, a 928 with nitrous, an endurance spec 996T with over 1000 lb torque, a 3.6T, and Racing Ray Willams' GT2 running ~17psi putting out 800 hp at the flywheel. (It was dialled down from 26 psi, capable of over 1000hp!)

www.metacafe.com/watch/421757/high_powered_porsches_on_a_dyno/

Hope you enjoy it!
kj

[renn68]

yes, it was a pretty impressive sight (and sound) - thanks for posting

[Esprit]

Ray Williams' GT2's an impressive beast

I'd still like a 993TT someday

[GravelBen]

nice.

A question though, if that enduro 996TT is putting out 1100lb-ft (~1500 Nm) or torque, why does it only dyno at 290 wheel KW? with that torque it must have much more than a 10 KW advantage over the 996TT X50 which ran 280 wheel KW.

[Kiwi XTR2]

Is that a problem with converting the drive ratio to get the corrected torque ?

[GravelBen]

I wouldn't think so, given the close relationship between power and torque - (ie power=torque*revs(*a constant for different units))

in this case the 996TT X50 (~450hp/330kw and 457lb-ft/620Nm factory quotes) ran 341hp/280kw atw on the dyno, so losses of ~32% (which seems pretty high, so maybe its losing a bit of power from heat-soak as they don't seem to have much airflow on the back end). Assuming the same losses for the enduro car gives 389hp/290kw atw which +32% is 513 flywheel hp (car may be capable of somewhat more than this if its being affected by heat-soak etc)

My thinking is, if a 450hp 996 turbo has 457 lb-ft, how can a 513hp 996 turbo have 1100 lb-ft? I'm sure just tuning it for more torque rather than power wouldn't be able to give anything like that difference.

[Kiwi XTR2]

On a dyno like that it is measured at the wheels, not the flywheel, so there is some maths to be done to get comparable torque figures. I don't know which gear they ran the two tests in or what final drive ratios the two cars have.

I'll get 1,000 Nm out of the Westie with the right gearing


Might end up weighing a fair bit more and wouldn't actually move

[GravelBen]

Kiwi XTR2 said:

I don't know which gear they ran the two tests in or what final drive ratios the two cars have.

Hmm yeah i see your point, I'd just assumed they were in same gear with similar ratios but given given how modified the enduro car is they may not be. There still isn't that much power difference between them, but I guess you can't extrapolate that to torque without knowing the revs.

I'd still expect much more than 513hp on a dyno from a turbo with 1500 Nm of torque though...

Edited by GravelBen on Friday 9th February 06:25

[Esprit]

they didn't list a torque figure for the 996tt..... the torque figure would be an ATW figure, which means it probably needs to be divided by the diff ratio (assuming it was done in the 1:1 gear through the box)

[GravelBen]

No torque figures were shown in the video but 1000 lb was mentioned by the OP for the enduro 996TT. Torque figure for the X50 I grabbed off the net for comparison.

I'd though the OP meant the 1000lb torque was a corrected flywheel value from the wording, might make more sense if it was an ATW reading though.

[peterpsg]

Hmmm, If my SBC is putting in at 6000rpm ~400ft/pounds, and that gets converted to say, 2000 rpm at the wheels, then, ignoring losses, you'd be getting out 1200 ft/pounds... deducting ~20% for losses then sounds about right...

Still, with that amount of boost, maybe it is 1000ft/pounds, you can certainly get that and more out of a V8TT.

[renn68]

Correct, - its at the wheels so you do need to know gearing