Dynamometer Results & Comparisons - Thoughts on low peak power

Hi from Australia

I have a z32 300zx with the Gen IV L98 (L92) fitted with a 231/239 .617/.623 Pat G / EPS cam fitted. It has a 4" intake with no MAF and a 4" K&N pod filter, custom headers with twin 2.5" exhaust and 100cpsi cats. 4L65E with high stall around 4000rpm. Stock Nissan 300zx twin turbo rear end.

Now the thing is, the car goes hard and ran 11.42 @ 118mph which im more than happy with, however it only reads 352rwhp on the dyno. (unlocked)

I am not one of those guys who chases a dyno figure, i am more just curious as to why this same sort of combo on your typical G8 would run well into the 420 - 450rwhp range and the reasons it can vary so much?

The only thing i can think of possibly restricting my car is my headers which ive discovered aren't designed correctly in terms of scavenging. (see pic)

http://members.ii.net/~kurt.dunstan/300zx/headerslhs.jpg
http://members.ii.net/~kurt.dunstan/300zx/headersrhs.jpg


Has anyone seen this sort of thing happen before? Could strapping the car down wrong cause this much of a difference? I find it hard to believe that it would read 100hp less than another car with the same engine ? I have all confidence in my tuner and know that the tune is spot on so its not that.

http://members.ii.net/~kurt.dunstan/300zx/dynosmall.jpg

How much does the car weigh do you know? Given that, I would not put any weight on the dyno results as clearly the car is running strong. It might not have the best numbers on the dyno with a big stall and what turns out to be shorty headers due to design, but it clearly runs hard.

My bet is a dyno error...as if you had a clear mechanical problem (valve float, spring issues, clogged cats) then you would not put down good numbers at the strip.

Put it on a dynojet if you want to compare numbers. Most the other dynos can be skewed big time by the operator.

Don't think the headers are that bad... not great but far better than stock manifolds. For the long run I would still redo them though. Looks like there is plenty of room. Just need a few more bends and a 4-1 collector.

Is it a lockup stall? Big stalls do kill dyno numbers.

z32 so I'm guessing not any lighter than a Camaro.

So cliffs - put it on a dynojet.

The car is 3240lb with approx half tank of fuel and no driver

I went to a dyno day once; that used the Dyno Dynamics Dynamometer. If I recall correctly everyone's power was down more than 10% when compared to DynoJet numbers.

I went to a dyno day once; that used the Dyno Dynamics Dynamometer. If I recall correctly everyone's power was down more than 10% when compared to DynoJet numbers.

Yeah even if the Dyno dynamics is reading low in itself, it still doesn't make sense why a commodore with same engine & trans would run an extra 100 hp. That's what I'm trying to understand. Even big stall unlocked cars

Yeah even if the Dyno dynamics is reading low in itself, it still doesn't make sense why a commodore with same engine & trans would run an extra 100 hp. That's what I'm trying to understand. Even big stall unlocked cars

Big unlocked stall, cam only L92 cars are putting out 450rwhp? Show me one.

I might have exaggerated a little with the 100+ hp claim. It just seemed mine was lower than usual. I'm not that fussed I was more interested in finding out from other people if it's pretty normal.

My 4000 stall drops power #s by 30-40hp. Lock it if you want a bigger #.

Your headers may not be optimum but I think you did a good job on them. They look nice. Why did you make them a tri y versus traditional long tubes?
Car runs good, I wouldn't worry about #'s.