Johnb55

Our local Subaru dealer had a fun car show/barbeque with a chassis dyno set up to do some dyno pulls. Just for grins I put my 997 GT2 up there to see what it would do. I was very pleasantly surprised! 617 hp @ 6,600 rpm and 581 lb-ft torque at 4,000 rpm at the wheels. Also walked away with a trophy for the strongest pull of the day.

The car has an EVOMS tune, GT2 RS intercoolers, a single mass clutch, lightweight flywheel, and a Guard diff.

Igooz

Wow! Impressive numbers.

Spyerx

hahaha... show up with a machine gun to a knife fight....

Rick GT3

what a BLAST!!!

Johnb55

Yeah, kinda... I was just curious to see what it would do. There were also some Vipers, Corvettes, and Mustangs there putting down down some strong numbers. Some of those modified Scubies are not to be taken too lightly either, I saw an STi do 480 whp.

Reid55

Well done!

TB993tt

Great stuff

A couple of questions:

Did they blow any air through the intercoolers ?

What sort of loading does this dyno do, how long was the power run was it a 6 second job or was it longer ?

Where did they attach the straps at the back ? last time I tried to go on a chassis dyno they attached to my lower arms and they bent them during the run !

Johnb55

No air blowing. They were two quick 6 second pulls. Ambient temps were about 45 degrees. They did use a Correction Factor. I assume they attached the rear straps to the lower a-arm mounting points. Fronts were through the wheels, which the car didn't like. It threw a code with the rears rolling without the fronts. I'll try to reset it with my Duramatric later today.

Here's a short video:

powdrhound

Whenever I dyno they attach the rear straps to the rear subframe cross member. The front goes through the wheels.

Congrats. Those are very nice numbers. It's interesting to compare the dyno of your VTGS to my conventional K16s. I am running ported housing with standard K16 hot sections and OEM 997GT2 compressors. This is on 91 octane and 1.2 bar. Did your tune not raise your redline as it appears to be at 6800 or did you guys just shut it down early? It would have been interesting to see how the VTGs would do above 7K. What fuel were you using?

Johnb55

Nice numbers there as well.
The dyno guy just ran it to the redline indicated on the tach, which is 6,800. It was still making good power as can be seen in the graph. The EVOMS adds 200 rpm to the rev limiter and runs boost up to 21 psi (1.4 Bar) conditions permitting. It was running on 93 octane.
I really didn't see where they hooked the rear straps to, the guys seemed very careful and proficient though.
I was able to clear the PASM code with my Durametric software. That was the first time I've ever used that, it's pretty handy.

TB993tt

I don't want to appear a kill joy broken record on this but the OP's dyno run was a bit of fun with a tool which can give him comparison against others on the day, basically his GT2 could spin up those rollers for 5 seconds faster than all the others the power and torque numbers are pretty meaningless if you want to compare them to a steady state braked manufacturer set of power and torque curves.

Hence you can't compare them to your Dynojet curves which again will differ from the OPs and the way the manufacture does it.

powdrhound

Yes, I think everyone understands that comparing numbers on different dynos is meaningless. Nothing new there. I was simply commenting on the shape of the curves which indicate how the power comes in. Nothing more nothing less. I just realized that the OP was on a Dynocom. I initially thought he was on a Dynojet when I glanced at his graph. Obviously apples and oranges.

TB993tt

It is not possible for a 5 second spin up of a known mass by a powerful TURBO engine to give a true representation of the torque curve to compare with the factory curves...
The factory curves have the engine braked for a period as the revs rise and are completely different hence why eg a 997 turbo has peak torque at 1900rpm according to the factory but there isn't a chassis dyno on the planet which can replicate this....

I know you know this but I was just looking at you dynojet curves and you have as much power at 4800rpm as you do at peak power ~7000rpm, this is obviously wrong and is because rollers can't measure high turbo torque it spins them up too quickly and delivers silly peaks like your 980NM !

Last time I had mine on a Chassis dyno (when it bent the arm) it chaffed the tyres as the operator tried to load it and he measured over 1000NM which is not just true.... I guess I am a bit frustracted because I'd like to do a power test to make sure all is present but apart from the fun aspect seems futile

Giantviper

Very cool and congrats on the win numbers you pulled. Which Subaru dealer in NJ was the event at?

My Subaru Dealer also owns a Porsche dealer next door. All Flat motors together I guess was the thought :-).

powdrhound

Nowhere was I comparing anything to factory curves. Not sure where you are reading that. Honestly, who really cares about factory curves? I certainly don't since a factory dyno is virtually inaccessible to the average Joe. After all, outside of what is posted by the manufacturer, 99% of dynos graphs that you see out there are obviously NOT on factory dynos but rather by guys using run of the mill dynojets, mustangs, or other chassis dynos like the one used by the OP. All of these dynos as you correctly mentioned naturally have their limitations especially when it comes accurately depicting torque peaks on turbocharged power plants resulting in an overinflation of the peak numbers. All of these dynos however are useful to VALIDATE CHANGES you make to the power plant when tested on the SAME dyno and ideally under the SAME atmospheric conditions. Nothing more. I'm good with that as it serves it's purpose and as such don't lose much sleep over not being able to test on a factory dyno. Would it be great to get some numbers on the same rig as used by the manufacturer? Sure, but it ain’t gonna happen so life goes on. Honestly, most people are simply trying to find out if the tune or the new XYZ gizmo they put on the engine results in a quantifiable gain, or in the OPs case, how it compares to other cars on the same rollers. For most people that’s good enough..