sweanders

How accurate is the dyno? Those numbers are all over the map..

Brett928S2

Hi ANDERS

They are very accurate...last time we got my car tied down well enough ....it was accurate to within 1 hp ...

All the best Brett

D_Schultz

Sounds to me like you came first by a good 50 Ft Lbs.... Probably had a much broader torque curve as well!

Good show

Brett928S2

Hi

Thanks for what its worth I am now thinking about 1000 hp

All the best Brett

Brett928S2

Hi All

Partial dyno chart.....



All the best Brett

Jim R.

So 379.2 RWHP=505 CHP?

Is that a ~25% drivetrain loss conversion factor? Not trying to be negative, just trying to do the math. We are used to 18% loss for the automatics, which would be more like 414 CHP if my math is correct. Either way, nice results and I bet it is fun on the bottle.

Jim

Brett928S2

Hi Jim

He had such problems holdiing it down and the autobox changing DOWN so much...sometimes 2 gears...that he had to look at all the partial runs and work out the hp and torque from those and this partial run....
Even this run had to be cut short at 5500 revs as hes was scared it would break loose... lol

And yes its HUGE fun when you hit the switch ))))))))))))))))

All the best Brett

sweanders

How about going back to the dyno and do a proper run to verify? It just doesn't seem right and I wonder where the 500+ figure comes from.

Brett928S2

Hi

Its not as easy as that lol...firstly I would have done a proper run IF we could...until I can figure out how to stop the kickdown activating totally its not possible...but I am back there soon anyway with the new MAXX progressive controller and over 600 hp (hopefully)
Eventually...I am aiming for 1000 hp...crank or wheels...not bothered which lol

All the best Brett

sweanders

To give you some perspective well running (better than most) I have seen dyno numbers in the ~300 rwhp range for GTS auto cars.

heinrich

yes. what he said.

heinrich

I think it's safe to say that your car cannot possibly make 500BHP and 500ft-lbs with a 4.7 and no super/turbocharger. I can believe 379RWHP from a good nitrous system on an excellent 5-litre S4, but that calculates to 474 even if you assume a 20% drivetrain loss, and we have come to believe that there is not 20% but rather 16% loss. Which places your actual crank hp at 451. And you have a 4.7-litre whose breathing apparatus is known to be a massive restriction.

heinrich

That's still very impressive though

Brett928S2

Hi Heinrich

Well...even on my partial run ..I got 379 at wheels (auto).....and I promise you that I will post a dyno here of my 16 valve with at LEAST ...500 rwhp...as soon as the progressive MAXX controller is fitted and I have moved up on jetting ....breathing doesnt matter with Nitrous....you are putting the extra oxygen straight into the cylinders...

As I mentioned....I am aiming for 1000 hp.....wheels or crank

I am not known at failing....

All the best Brett

PORSCHE 928 S2 AUTO V8 4.7 LTR 1986 IRIS METALLIC BLUE WITH X-PIPES ,RMB ,PROMAX CHIPS, KICKDOWN SWITCH.K&N.NITROUS KIT 150 HP - 505 BHP / 500 FT LBS TORQUE
PCGB UK 928 FORUM MODERATOR - Email managingdirector@pchealthcare.co.uk

drnick

heinrich, not sure if you remember that the S2 4.7 has different; heads, cams, intake, injection from the US cars.. 310 bhp as standard vs the S4 at 320.