I'd bet $20 if you took your car and the other coupe to the track and ran, your trap speeds would be nearly identical. ETs would vary due to 60 foots, but trap speed indicates available power.

From the dynos I've seen on these cars, the VQ's performance can vary due to operating temp, intake temps, heat soak, etc. It appears the numbers can vary by as much as 8whp/wtq on the same car between runs. I've personnally seen as high as 5whp on my Maxima on a back to back runs within 2 minutes, but if I let the car sit for 15-20 minutes with the fan blowing on the motor, the car will dyno within 1-2hp. I've seen the same thing on any other car I've seen dynoed. SC'd Cobras, Maximas, LS1 F-Bodies, G35s, S2000s, SR20DET 240s, Lightnings, you name it.

I know a lot of guys on here put a lot of focus on getting the G35/350Z to operating temp (which is downright hot) and then making the run. I've always dynoed with a cool motor because that's how I race the car at the track (ice on the intake manifold between passes, 30-60 minute cool downs, hood up).

 

We had a bone stock 05 6MT Sedan put down 245rwhp / 218ft.lbs (IIRC, the first run was 241rwhp and 225ft.lbs). The car had VERY low miles and it sounded like a bad tank of gas too, so I don't think 250rwhp out of a broken in 05 6MT car is out of the question. The higher rwhp ratings on the 350Z may have something to do with the different driveshaft too. Lighter rotating mass will show up as more hp on a dyno, even though the motor makes the same, the lighter mass translates to less losses in the drivetrain. Just like with a lightweight flywheel, it doesn't change the motor at all, but shows up on a dyno run...

 

What rpm did it make peak horsepower?

 

Well, the RPM pickup wasn't working 100%, so we had to get the numbers by the mph, but from the looks of things, it would have been about 6500rpms or so. It definitely has a different power curve, when compared to the older motors. It has a VERY flat torque curve, power is very linear all the way through the powerband and there are no dips or humps anywhere in the powerband.

I'm going to go back with a few other cars, hopefully within the next few weeks, and get better numbers and some printouts. Hopefully they can get their rpm pickup working by then....

 

Hi Alex, glad to see that your numbers pushed closer to 240hp. I have a question though, do you think the difference was due to a better dyno run or to the cooler air temps? Just curious. It was great to meet you and thanks for letting me borrow your jacket!
Jen

 

Jen, I was really frustrated at first but then I realized I had run my car so hard shortly before. My air intake temp measured at 227 inlet, and when we put it back on the dyno (when everyone else was done), it was at 124 (even after cooling off), so I'd have to say that the temp played a big role in the events of the day. It was great meeting you as well, and you're welcome on the jacket any time.

Alex