Stillen Headers installed - Review/Pics/Vid/Dyno

wstar · 04-22-2009, 03:53 PM

Quote:

Originally Posted by semtex

All in all, I have mixed feelings on this (based on the DD results). I like the HP gain. I like 317.2 a lot better than 306.4. But I'm not pleased about the loss of lower mid-range torque.

Are you sure that the low-rpm torque loss wasn't just from ramping the throttle in? On my DD run, I don't really trust any of the numbers under 3750 rpm or so as I'm pretty sure the engine wasn't solidly WOT until shortly before 4K. Even then, the way my torque doesn't really peak up until about 4250 is suspicious (this may have been lag between hitting WOT on the pedal and the engine really starting to breathe like WOT).

Given the data we have so far (including yours), I think it's fair to say that the headers aren't great bang per buck (and especially aren't good bang per installation hour), but I have a hard time believing we really lost torque on them given the graphs and the unknowns.

There's also the ECU consideration. The headers may provide better gains under good tuning (or not), we'll have to see.

semtex · 04-22-2009, 03:59 PM

Quote:

Originally Posted by wstar

Are you sure that the low-rpm torque loss wasn't just from ramping the throttle in? On my DD run, I don't really trust any of the numbers under 3750 rpm or so as I'm pretty sure the engine wasn't solidly WOT until shortly before 4K. Even then, the way my torque doesn't really peak up until about 4250 is suspicious (this may have been lag between hitting WOT on the pedal and the engine really starting to breathe like WOT).

Given the data we have so far (including yours), I think it's fair to say that the headers aren't great bang per buck (and especially aren't good bang per installation hour), but I have a hard time believing we really lost torque on them given the graphs and the unknowns.

There's also the ECU consideration. The headers may provide better gains under good tuning (or not), we'll have to see.

Even if it was from ramping the throttle in, why would it show a loss? The throttle had to be ramped in the last time as well, right? I don't know. I'll tell you guys my driving impression so far though. I can notice the loss of torque on the low end. I mean, before the dyno, I kinda suspected it, but now I have confirmation. But paradoxically, it feels quicker once I really get into it, which I guess is where the hp gain comes into play. Sound wise, I'm still undecided as to whether I liked the way my car sounded before the headers vs. after. To be 100% honest, I do not feel that this was money well spent. I'm actually toying with the idea of having my stock headers put back in. But then that's another $750 out of my pocket, right? So I probably won't. Plus you're right about the tune. It'd be premature to rip these out until I see what a tune will do.

wstar · 04-22-2009, 04:14 PM

Quote:

Originally Posted by semtex

Even if it was from ramping the throttle in, why would it show a loss? The throttle had to be ramped in the last time as well, right? I don't know.

Well, the throttle inputs might not be the same between the runs. I think on my next DD run, I'm going to ask the guy to make sure he drops back under 3K before he floor the throttle and takes the run. It's not a very well-controlled variable, and since most people are just looking for the peak HP number anyways, it doesn't matter to many. It would be nice to hook up OBD-II to the dyno machine and get throttle position mapped onto the graph as well if that were possible.

Quote:

I'll tell you guys my driving impression so far though. I can notice the loss of torque on the low end. I mean, before the dyno, I kinda suspected it, but now I have confirmation. But paradoxically, it feels quicker once I really get into it, which I guess is where the hp gain comes into play.

That's what I've noticed as well, mostly in the form of the car having less "jerk" at low rpms (esp at 3k-ish and below). Looking at my graph here:

The low torque before hitting the peak at 4250 can either be low-rpm torque loss from headers, or it again could be throttle input issues near the start of the run, I'm not really sure. I'm pretty sure everything before 3500 is from lack of WOT though.

Quote:

Sound wise, I'm still undecided as to whether I liked the way my car sounded before the headers vs. after. To be 100% honest, I do not feel that this was money well spent. I'm actually toying with the idea of having my stock headers put back in. But then that's another $750 out of my pocket, right? So I probably won't. Plus you're right about the tune. It'd be premature to rip these out until I see what a tune will do.

I actually like the sound of my full setup most of the time. The only thing that still bugs me (and that the headers undoubtedly exacerbate) is the extreme rasp around the 2500-3000 range even at light throttle. I wish I knew how to fix that with some kind of rubber damper (like the two that are already on there from the stock setup).

semtex · 04-22-2009, 04:18 PM

Quote:

Originally Posted by wstar

I actually like the sound of my full setup most of the time. The only thing that still bugs me (and that the headers undoubtedly exacerbate) is the extreme rasp around the 2500-3000 range even at light throttle. I wish I knew how to fix that with some kind of rubber damper (like the two that are already on there from the stock setup).

Hmm...I don't detect any rasp. I wonder if the fact that I had my headers wrapped is making the difference.

wstar · 04-22-2009, 04:20 PM

Quote:

Originally Posted by semtex

Hmm...I don't detect any rasp. I wonder if the fact that I had my headers wrapped is making the difference.

Could be.

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