I can't wait for my car to sound like that.

Also either the humidity is robbing you of a good bit of HP or the dynojet is reading a little low. I expected a little more power from those mods on a dyno jet....
We will see what I get :)

I agree with RCZ, I would expect a little more power with all of the mods done so far, but man does that sound sooo sweet! I was planning on this exact set-up. nice work!

:drool: Makes me wish the meet hadn't fallen through.

Well as I said, the numbers look low to me too. We've got 4 possible excuses now, and it's probably a combination of all of them: (1) Dyno/Car variations, (2) Being in 4th instead of 5th, (3) the humidity, and (4) 7AT vs 6MT. Monday looks to be better on humidity, so I'm going to try and get 5th gear runs at the same DynoJet and/or a Dyno Dynamics place then, pending the scheduling working out.

God your car sounds so awesome.

I also hear that rasp you were talking about in your other thread. Fix that and it would be near perfect.

I don't know if rasp is the right word for it (seems to have some fixed connotations to some people), but there's definitely a vibrational noise at certain RPMs. I hear it pretty distinctly inside the car when driving, but I couldn't hear it much at all from outside when I was videotaping the dyno run. I think from the outside the actual exhaust sound drowns it out.

Being the paranoid worrier that I can sometimes be, my main concern is it could be a small leak that only opens up under the pressure of a loaded run (never hear it revving the engine in neutral), but the rational part of my brain says I've rechecked those bolts plenty of times now, and there's no leak. Most likely it's something else vibrating: perhaps something in the lower engine bay is rattling against the piping near the headers/cats, or perhaps one of those flimsy, thin undercar heatshields is vibrating in response to the exhaust, or something of that nature.

Anyways, I just got two more dyno runs scheduled today, one at the Dyno Dynamics place (Engine Logics), and a second run at the same DynoJet I used at the start of this thread (but will do it in 5th gear), so hopefully this evening we'll get some clarity on the numbers.

Yeah, I was talking about that tinny noise characteristic of metal on metal contact. The note wasn't raspy at all, and sounded excellent. Sorry for the poor choice in wording.

I see others with the Stillen catback are having similar issues. Hopefully Josh will find a solution quick.

At this point I doubt my vibration noise is anything specific to the Stillen catback. I know the catback part isn't touching anything but its own rubber hangers and has good clearance.

Just got back from EngineLogics where I did the Dyno Dynamics run. They put me at 300rwhp and 242rwtq. Graphs came out very consistent, it's a really nice machine. I'll scan them at a copy place in a few hours when I go out for the DynoJet retake. This is still lower than semtex's numbers, but it's a lot closer, within the margin of error for differences in car, dyno, weather, and 7AT/6MT.

^ Except I don't even have the headers installed yet and I'm making 306.4whp. My guess is that the difference in drivetrain loss between 6MT and 7AT is coming into play here more than anything. Still some good numbers though. 300whp on a DynoDynamics is nothing to sneeze at. Congrats!

Hmm... it was my understanding that the noise was coming from clearance issues with the catback?

A few of us have had clearance issues, which does make a vibration noise. However, on my car that problem is solved. I'm talking about some other noise.

Yeah I'm happy with it. 6hp isn't much, and there are a lot of variables in play here between your situation and mine.

Re: the headers, the guy at the dynojet shop (carboy) said he didn't think headers were going to do much on this car. Who knows if he has any idea what he's talking about. Apparently he has a long history with recent Nissan engines though, and he (and everyone else in the shop apparently) are all Japanese immigrants if that makes any difference. On the other hand, this is the same guy who ran my car in 4th gear, so take whatever you want from that :) I'm leaving in 20 minutes or so to go try the 5th gear run there.

Ok I just got back from the DynoJet shop. Learned a few things:

A dyno run on 7AT in 5th gear isn't really possible with our current stock ECUs, they hit the 160 mph speed limiter at around 7K rpm. We actually tried it, and the ECU basically holds the gas pedal dead on 160 mph when you reach it, it won't let you accelerate any further. The 7AT has a different gear ratio in the diff than the 6MT (7AT = 3.357, 6MT = 3.692), which is why you 6MT guys are able to make 7.5k (just barely) in 5th.

In any case, the lines looked about the same, if anything roughly 5-10hp lower throughout the rpm range versus the 4th gear pull. The graphs he showed me afterwards, the data seems to die off even earlier than what I observed during the pull (more like 155mph) and topped out at 288hp, so I don't really know what's going on there.

So I think 7AT pulls on DynoJets will need to be in 4th for now, at least until we can raise the speed limiter. I also suspect this particular DynoJet is need of some maintenance and/or calibration.

The Dyno Dynamics guys claim gearing doesn't matter on their machines, due to a different theory of operation.

Very interesting... Thanks for the update.