Phil Raby

Well, there I was at G-Force's rolling road, primarily to do some tests on an MGF but it seemed rude not to put the 964 on the rollers, considering its the most sophisticated set-up in the UK...

After a few worrying moments when I saw 216bhp appear on the readout I was delighted with a figure of 258.5bhp

Also, the guy there had done a lot of work on 964s and had some revealing info on engine upgrades:

Drilled airbox - 2bhp
Cup bypass pipe - 10bhp
Replacement rear silencer (any) 0bhp (but worth doing for the sound...)
Larger throttle body – 5-10bhp
Hot film conversion - 50bhp (in conjuction with Cup pipe)

And he had the graphs to prove it!

He also said my engine felt superb and was very impressed with it. Indeed, someone else there offered to buy the car!

Cheers

Phil

robmug

Nice one Phil. Nice to see a 10 year-old car producing more than factory stated output. That's build quality for you.

You must be pretty chuffed!

Phil Raby

Yep, chuffed to bits!

Phil

Christer

Phil

For comparison (well on a different dyno) I was at 207rwhp and 222rwhp after the exhaust upgrade. What was your torque? It seems that JZM might have been right in their diagnosis that my engine was alittle down on power after all these years!

For a more accurate result though, we should try to get on the same dyno some time....maybe G Force is hugely optimistic or JZM the opposite. Or maybe they are both right.

Good result on the face of it!

Andy Roe

Phil,

Just before you bought the car, the engine had just been re-built - right? Were any upgrades done to it at that time?

Andy

Phil Raby

Well, just looked at the torque and it was producing 242lb/ft at 500rpm (factory figures 228 at 4800) which is rather surprising... (EDIT: Actually that would be very surprising! Perhaps I meant to type 5000rpm! )

Yes, the engine had been rebuilt by an OPC and, as far as I know, was done to standard specs. The only changes I'm aware of are a Dansk silencer and the drilled airbox.

pzull

Phil,

What was the transmission loss number that they used? Was it an actual measured number or a guesstimate?

That could be reason behind different readings on different machines. Better to just use the rear/four wheel reading without extrapolating for flywheel figures.

Another factor could be the differences in gear ratio used when doing the dyno run. Anyway this was what I was told by a dynp operator here.

Flying Finn

I'll say, that is some LOW END torque, my car doesn't even idle so low...

Nice results Phil!

Phil Raby

Pzull, It uses a different system to conventional rolling roads and is able to calculate the loss. No, I don't know how it works but go to http://www.g-force-motorsport.co.uk/dyno/dyno.htm for more info. And they run 911s on at all the time so I'm confident the result is accurate.

Finn, yep impressive, eh?

Phil

robmug

Phil

That link says the opposite; that there isn't any way of calculating the loss - their final comment is "If you don't know how much power you have at the wheels - you don't know how much power you have!! "

Phil Raby

Umm, so it does.

Well, the guy went into great detail about how the system worked and was confident with the way the flywheel figure was extrapolated... I figured he was the expert and left it in his capable hands...

Cheers

Phil

John Boggiano

I think there's a way that a good guestimate can be made by comparing the 'run-up' with the 'run-down' readings.

Naturally, I don't have a clue about this, but it seems to ring a vague bell!

Phil Raby

I think this is how the G-force machine differs to conventional rolling roads - it doesn't need to do a run down...

If I'd known I was going to get the Spanish Inquisition I'd have paid more attention to the explanation at the time...

Phil

DaveK

Well, you've inspired me (bet you don't hear that often.....)

I've been meaning to do this for a while - I'm now booked in at G-Force at 11am on Monday.

If the results show I only have 20bhp and something dreadfully wrong with my car, I'll blame you!

Phil Raby

Cool. The RR is run by an Aussy guy called Chris. He'll give you the option of staying in the cell behind a bulletproof glass screen, which worried me somewhat

I stayed outside!

Look forward to hearing how you get on. If I had time, I'd pop down, but I'm not sure I'll be able to.

Just a thought. They do 'shootouts' at £50 a car, but a minimum of 12 cars are needed. I wonder if we could arrange it?

Cheers

Phil