more power than expected

**hamburger68** · 03-01-2007, 04:34 AM

ok, here's the deal:

my car is supposed to have 288 hp stock (german export model + measuring norm), but it dynoed 363 on monday (also german standard at the crank)... not that i complain!

my mods are: K&N + lid, 3" dynomax catback, HPP3 (stock thermostat), new iridium plugs. the car is a 98 Z28 A4.

are those mods really worth 25% more power? i really wouldn't think so...

Any ideas???

**ss~zoso~ss** · 03-01-2007, 06:23 AM

it put down 363 at the wheels?

**ss~zoso~ss** · 03-01-2007, 06:23 AM

that seems really high, those are numbers you'd expect with a set of headers and a mild cam

**hamburger68** · 03-01-2007, 07:10 AM

not at the wheels, at the crankshaft.
the 288 german hp must be equal to the stock 305 hp of the us-versions official rating (different measuring standards).

my point is: 75 hp difference between the official stock rating and the dyno run seems much, considering my mods.

**SPECOPS94** · 03-01-2007, 08:30 AM

Don't know how much the 98s were under rated in terms of HP. The 2002 were under rated by 30 HP for insurance purposes.

**hamburger68** · 03-01-2007, 11:41 AM

so, with that taken into account, would you say the mods listed above would be good for that 40 or 45 extra hp? (taken the 30 hp overrating?) cuz i figured they'd be good for 30 at best...

SMKDFRD · 03-01-2007, 04:02 PM

I think you should get your car dynoed again. But this time measure the HP at the wheels and not the crank and I think you'll get the "right" numbers.

**hamburger68** · 03-02-2007, 12:15 AM

...must always read the 2nd page....

somewhere between a heep of numbers on the 2nd page of my dyno slip, i found my rear wheel hp: 312 !!!
still, from the stock rating, wheel hp should be around 260 or 270 at best...
(i still don't complain, just trying to put this into perspective) the guy at the dyno shop said too, he never saw that much difference between stock rating and dyno numbers!

...

**Roastem** · 03-02-2007, 04:12 AM

312 rwhp is about right for your setup. Put some longtubes on it, delete catalytic converters, and put a big ass cam in there (.550-.600 lift, 220-230 duration@0.50") with some port and polished LS6 heads. If your money is right, then go for the AFR 205cc heads, or the Trick Flow Twisted Wedge heads. And throw some 3.73 gears in there with a 3200 rpm stall. Tried and true recipe for success!

**ss~zoso~ss** · 03-02-2007, 07:16 AM

Your numbers are right, Perfect for the mods

the factory rating is often taken as wheel hp in our case, but for the most part the factory rating is often somewhere between wheel and flywheel HP

**hamburger68** · 03-02-2007, 07:50 AM

thanks for the info! to me it was just strange that a manufacturer would underrate their cars... german brands usually dyno around their official rating, usually rather a bit less. since we're germans, we are very stict about our industrial standards.
always very accurate, jawohl!

so now that my reading is correct, i can sit back and enjoy my unexpected extra oomph!