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MY BHP? I'm puzzled.....

carreraboy

carreraboy

PCGB Member
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Well you experienced Anoraks and Grease Monkeys i'm a little nicely baffled. I reported when I bought the car that it was not as "quick" as my old Butzi car which was giving about 290BHP true, very responsive from low revs and the Clubsport (ALLEGED STANDARD 260BHP) seemed a bit sluggish until I got it on full cam, and thus found myself actually driving it more constantly at higher speed where the car preferred to be, this was all before my first track day.

Well three track days latter and I'm sure she is not standard 260. Why? well simply, once maintaing higher revs (where a race car spends it's life) she just seems to be right on the power curve holding huge torque and not fighting and gasping for air. But just wants to maintain 5,500 - 6,500 RPM all day and pulls like nothing, in this rev range unlike my old car, that yes would pull but just seemed not to have the same stamina/grunt at this level.

Also in a straight line compared with a certain 993RS Clubbie standard 300BHP she matches the performance in line acceleration all the way with nothing in it. Indeed compared to other factory 280-300BHP cars coming into any straight once full on cam they seem to disappers as if leaving the Cling Ons in the Enterprise.

Well it's an ex-race car and has obviuosly had a fairly fresh full engine rebuild, no smoke and is nice and tight, so with all those part bins lying about who knows, maybe some Cup Cams, high end remap etc etc...

Proof will be when I get it Dyn'od.
 
Don't think cams are too serious or aggresive as the car ticks over sweetly...no lumpiness at all,,,agree that the car feeds on the revs,,,personally I think it is a remap......

agree there desn't seem much in it at some points of the rev range with a 93RS, the difference is the 6 versus 5 speed ratios....in 3rd, the 64 can hold the gear longer than 93 can as 4th is required,,,then 93 goes...also more torque and lower ratios sees the 93 literally clear off into the distance when coming out of a turn.
The car feels >260bhp to me, but you really need to compare it with another car using similar gearing to get a true bearing, one drag in a straight line in 3rd doesn't really give a true barometer to the cars output.

Des, either way the car drives very well, it is certainly quick enough for you to get to grips with at the moment [;)]
 
It means: Check the BHP and the torque on the dyno, Des.

And now for you, Des:
Woltonial Rohl says: I´ll show how I´m quicker in a 356 than you are in your 964 RS. He will be, I´m afraid. No matter what the dyno says.
 
Hacki, obvious answer, but clearly not all dynos are calibrated or have same adjustment factors used in the UK. Quite poassible Des could get a 280 read at one and a 290 at the other.
I have suggested to Des, he goes to a din70020 spec rolling road and explain he is thinking of buying the car and doesn't need a bhp read for bragging rights,,,which is how I went about it [;)]

Des, I am sure you will encounter many RS at Spa where the owners know their output, perfect for comparison purposes,,,,,even the "butt dyno" jumping from one to the other can give a reasonable idea [:D]
 
ORIGINAL: clubsport

I have suggested to Des, he goes to a din70020 spec rolling road and explain he is thinking of buying the car and doesn't need a bhp read for bragging rights,,,which is how I went about it [;)]
Click to expand...

...and the numberplate with his initials is just a happy coincidence.... [;)][;)]
 
Nice one Rich! I was going to dress up as a Gay Vicar thinking it was a VW Beetle conversion wearing Leather Sandals......[;)]
 
Weltmeister at Silverstone seems to have the most respected rolling road in the UK - lots of Porsche numbers to compare against. It's where EVO do their tests on production cars (and I'm not saying that because my 993 came out with 282 Bhp there [;)])

Pete
 
Another "issue" with Weltmeister's RR is that it doesn't convert to flywheel HP. It produces an at the wheels figure and then to get the flywheel figure, you multiply by an abitary amount based on experience. If your drivechain creates more or less losses than standard, the figures are then incorrect.

However, measuring power at the wheels is, IMO, the best way of doing things as that is what really counts. It doesn't matter if you have 1000 bhp if, due to loses, only 200 bhp ends up at the rear wheels!

That said, if I were Des (perish the thought!!!) I would go to one of the Porsche specialists who has a RR that calculates the flywheel power during the coast down period of the run and who has also got a lot of 964RS experience or to go to Weltmeister with somebody who has has their car tested on other RR's. That then gives a comparison point.
 
Hi,

I thought the WRC Dyno used a formula to calculate the flywheel bhp on the rundown as you describe?

Certainly my readout was for Flywheel BHP, and was calculated instantaneously?

Maybe 9M would be a better place for an RS to be tested, they should have enough experience with standard 964's RS's?

Pete
 
WRC have a Dyno Dynamics RR. Now, I admit I am out of touch a bit (about 8 months), but Dyno Dynamics didn't used to calculate losses during rundown. They used to apply a single factor to all cars of the same type. This may have changed.
 
Simon the DD rolling road actually has a dedicated Porsche mode. You will not find a more accurate chassis dyno for a flywheel horsepower test. The absolute test is to remove the engine and run it on a bench dyno.
The at the wheels is used only for Mitsubishi Evo's as the flywheel programme is not close enough.
Mo the issue we had was software related but it only indicated a slow spool up, the numbers never change. If the gearing is calculated innacurately then the torque will "bunch up" on the graph and be a little higher but not hugely.

Cheers

Allan
 
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