Hmm...I'm not sure how they're getting 10+ tq. Well, maybe if the rest of the exhaust is stock? I think that's what RelentlessRY did right? And he said he made tq on the top end but lost a bunch in the mid-range?

Alright, here's the video. (I'd better get some rep pts, tvfreakazoid! ;) I wasn't going to bother doing this until you asked.)

Thanks for the external vids, Semtex! That second graph was about as linear as it gets for whp. Even though the headers aren't quite where you wanted them, what is your impression of your setup as it stands?

S.

Awesome man. Nice results on Sharif's dyno :D

Chris

Thanks for the info. Semtex.

You know... I want to get them installed just to see the results of the full stillen setup....also chances are that the tuning will benefit a lot from the headers....

I already stated how much driving I did after the header installation in a previous reply to RCZ (see pg 2), and the afr is shown on the first Dyno Dynamics sheet from this morning. I did not wrap the headers to cure whatever you said about catalyst warm up time. I wrapped the headers to increase their efficiency and reduce heat in the engine bay. I've used parts from both Stillen and JWT, and IMO they both make quality parts.

Looks like you're making great power with just the typical bolt-ons.

I'm sure you'll make better gains with the headers on after a tune than without them.

Did you guys chuckle a little too or was it just plain annoying? It was both for me.

both

no thats not it.

easy there. since when are hondas cheap? cheap in what way? stop generalizing; thats what ricers do. as enthusiasts, learn to respect other cars for the credit they deserve.

+1

Back in my Mustang days, gains from long tube headers were not realized until the car was retuned for them. Granted, you did get some power from bolting them on, but a tune really woke them up. Now, the Stillen units are not what I call long tubes, but they are equal length at least.

When tunes become available, I believe we will see more gains.

I like it. I'd prefer the exhaust to be a little throatier sounding, but it's not bad as it is. It stays quiet until you step on it. I suspect that most people think this is actually a good thing, but I guess I'd just like a little louder all throughout the band. It was throatier sounding and louder in the low to mid range with the stock headers. I'm eager to get a dyno tune though. I suspect that as much gain as the car as made, there's still a good chunk of untapped potential. The UD pulley goes on next, then a tune.

I'm not sure I'd call piggyback units a 'hack job'. I think it just depends on the quality of the unit. I do prefer ECU reflashes though. They just seem 'cleaner' to me, if that makes any sense. But ECU tuning is definitely not my area of expertise. In fact, looking at the AFR data, I noticed that the line slopes downward as rpm increases. Does that mean it's getting leaner as rpm climbs? Or richer?

Getting richer.

Sharif used a sniffer in the tailpipe.

Semtex, these results do not surprise me in the least. They are very similar to my own experiences.

My revup had the oil consumption issue, and was replaced under warranty. While the engine was out, I bought some headers, and the dealer agreed to put them on for me while the engine was out of the car - for free. After breaking in the new motor, I was surprised that I didn't notice any gain(seat of the pants).

I then dynod, and even with the headers, the new motor was making ~10hp/10tq less throughout the whole rpm range versus my old motor. It took the utec and a tune to regain the lost power.

I don't know if it was just a difference in motors, or the addition of the headers, but the headers definitely hurt the driving experience of the car. I don't care for the sound(and I have test pipes). I lost quite a bit of low-end torque, and that combined with my lightweight flyweel, really took the balls out of the car. I'm just glad I didn't spend any time or money on the installation.

Sadly headers on the 3.5L since the HR came out has been a waste of money as the stock ones are already pretty efficient. I wasn't expecting to see much gain at all. Dynojets are the ones to believe over the other dynos as they are the most accurate.

Well, I think the real question is what happens when tuning enters the equation. Would I make more power with the stock headers and a tune? Or with the Stillen headers and a tune? Tuning could change everything. There could be gains to be had from tuning with the Stillen headers installed that would not be available otherwise (i.e., with the stock headers).

Tuning will always prove to give gains as the car isn't running as efficient as it was tuned for when it was stock. So adjusting the A/F ratio to the new mods will definitely help.

i think some ppl are looking at your installation as kinda a fail, which I believe its not. it did gain you hp, and that was the goal right? I do agree that its a PITA installation for as much hp as you gain for intakes, but a gain is a gain. congrats, and i cant wait for you to get a tune!

You'll see gains, but then again you'll see gains with a tune without the headers.

I really don't see the point of doing headers on the HR or VHR. They are already equal length from the factory; and the fact is that the engine is not going to benefit from larger diameter manifold piping; not NA at least.

Semtex don't worry, I am doing mine for sure to either back-up or negate your results. I will be doing it with the full stillen setup to see what happens to the numbers. The point is to get more power out of the car no? I think you have successfully done that and at the end of the day 11whp isn't so bad. I think we will benefit from having the headers once we get into tuning. With the stock tune, we may have lost backpressure and lost a little tq, but once we are tuned and we are flowing more air through the system, we will benefit from the extra flow. Meanwhile those without the headers will suffer a little from the obstruction. I think without a tune, the stock ones are pretty dead on the necessary flow. With a tune, the upgraded ones will be dead on.

Yep, I agree. I don't think it's a fail at all. The results may be a little underwhelming, but I think that's just because we've seen such insane gains from all the other bolt-ons up to this point. But let's be realistic here. Getting +18hp from intakes is insane, and getting +11hp from headers, while not as impressive, is still a very decent result. Or to put it another way, if we feel disappointed at the results from the headers, it's only because we've gotten a little spoiled. I agree that we should greatly benefit from a tune, and we'll find out for sure soon enough. Sharif said that he expects UpRev to have their software ready for the 370Z in about 2-3 weeks. He also said that he estimates he'll be able to get another 15 whp out of my car. Time will tell!

nice numbers!!!! now some track time?

324.6 WHP & 263.94 ft/lbs TQ (DynoJet)
holy crap, ur at the whp that others are seeing to the crank!

Now that you have installed all these goodies what are you getting for mpg?

15.4 mpg - about what I was getting before.

I'm curious regarding about your numbers. They are different types of dyno machines out there, which one is more accurate? Is the dynojet that u used pretty accurate?
I read on this forum that certain dyno machines aren't very good. I just can't remember what the name is. But I've heard dynojet on this forum and I think some said that it's not very accurate.

Accuracy isn't a big deal as long as you use the same dyno and get baseline numbers first. It's easier to just compare gains (and losses).

I just looked at the dynos in detail for the first time. I have to say that headers are totally a waste. I know that's gonna piss some people off - sorry about that.

First, I find it odd that the dynojet showed so little change yet sharif's dyno showed such large gains(comparatively). Dynojets might not be the most tuner-friendly brand of dyno, but they are generally exceedingly consistent.

Unfortunately, the only graph you have that is overlayed is the torque graph. Looking at that plot, you don't start making any more power than before until about 6750 rpms. That means that in the real world, you won't see any difference unless you spin the piss out of the car. Realistically speaking, you'll see a very small(10whp) difference, and that will be for less than 1000rpms. That kind of gain won't be perceptible until you reach something like 4th gear, where you're actually gonna be in that range for more than a split second.

I agree, actually. But the big unknown is what happens once a tune comes into play. Will these headers 'come alive' and yield significantly more gains with a tune than would be seen if I just had the stock manifold? If so, then it's worth leaving them on. If not, I'd just as soon take them off and have the stock manifold put back on, because as things are right now, I think the car was more enjoyable to drive with the stock manifold. In other words, if I wasn't planning to get a tune, it'd be a no brainer. But I am planning to get a tune, so now it's a bit of a gamble either way. Wish I had a crystal ball right about now.

Are you getting much of a "lag" response with half-full throttle past 3-4k rpm? I'm still stock, but that's what I feel under 3k RPM on up under half throttle (still breaking in).

^No, not past 4k rpm. But up to about 3500 rpm, the lag you're referring to has gotten a little more noticeable. See, I've lost a little low-end torque with these headers. Now, that's to be expected, because the backpressure has been reduced on account of these headers flowing a little more freely. But usually that loss in the low-end is made up for by gains in the rest of the rpm range, hence it's a fair trade off. I have no such gains, at least not any significant ones. My thinking, however, is that it'll be good to have these on when I get a tune, because like I said, I've lost backpressure because these flow more freely. Better flow usually means more room for gains via dyno tuning. I think I'll be glad I installed these in the long run, once I get a tune. Keeping my fingers crossed anyway.

Tune will fix it. Mine had lag after the HFCs and the tune fixed it.

Yea, I figured the headers would sacrifice torque without a tune. Still debating about getting them.

NISMOZ, did you leave your headers alone and simply tune with HFC and exhaust?

Berk HFC is under my desk and mid-June ETA for my F.I. exhaust. Tony at F.I. is experimenting with different configurations than the G37 like eliminating the H pipe and going for true dual at the mid section (I think). More variables there...

From your posts, it appears you've had significant gains from HFC and exhaust. That's all I'm thinking about doing besides debating about headers and keeping the stock airbox... last is UPREV.

Seems the common trend in headers.. I look at headers as a torque-adjustment tool on an engine. Rarely do you see poorly designed headers on factory cars anymore, they are probably one of the only well-thought and designed pieces connected to an engine. It's the balancing point or translation of power if you will. Toying around with headers usually will just shift power from one point and place it somewhere else, rarely does anybody see gains by using them these days.

I installed headers on my previous WRX and the same thing happened.. despite the vehicle being turbocharged, it still robbed torque and gave a very discrete bump in HP between 6000-7000 rpms.. To further make things worse, my friend had the same experience and he hated the headers so much for the torque loss (and that it completely removed the burbly sound of the boxer engine because the headers were equal-length instead of odd-length) that he put his stock headers back on and said the car was so much more streetable because he had his bottom-end torque back again.

I think i'll stay away from headers until Stillen decides to release some generation2 models and invest more time into the development.

-Div

Those are some very impressive numbers. 317 whp on Shariff's heart-breaker in impressive considering what others usually do on that dyno.

would installing headers on a 370z make the exhaust much louder? if so, is it a nice louder or bad raspy louder?