Need dyno graphs for headers!!!
Originally Posted by THX723
Hey Nismo G,
I've been around since the inception of the G35/350Z. There has not been a set of headers that made significant or otherwise "worthwhile" power and independently verified and substantiated. That also includes the DC Sport headers I personally own.
Many of the lesser known brands were alleged to have been base off of the very same DC Sport design (e.g. Strup, Alpha Works, etc.)
I do have pre/post dyno plots of my DC Sport headers. I will post them when I get home, as I'm still stuck here at work. Let's just say I'm glad I didn't lose much of anything. Lost some power below 3500 and gain the same amount between 3500-4500, which gave the false impression there is a nice bump from 3000 on up by the seat of the pants. Top end was unchanged. Given the amount of labor and cost involved (header install is a PITA), it is the "one mod" I would unequivocally pass up on if I had the chance of a redo.
The OEM exhaust manifold, albeit not the prettiest thing, isn't as lousy as it looks. Upgrading to after market headers for the G35 will not net you the uniform gain across the board as shown in the Alpha Works dyno. In fact such a characteristic response is almost always due to the ECU, a tell tell sign that the ECU reset procedure before each dyno was not performed. Intake and exhaust tuning has much to do with resonance as simple flow increase. As such, the gain (if any) will almost never be uniform. That Alpha Works dyno plot is best ignored.
I've been around since the inception of the G35/350Z. There has not been a set of headers that made significant or otherwise "worthwhile" power and independently verified and substantiated. That also includes the DC Sport headers I personally own.
Many of the lesser known brands were alleged to have been base off of the very same DC Sport design (e.g. Strup, Alpha Works, etc.) I do have pre/post dyno plots of my DC Sport headers. I will post them when I get home, as I'm still stuck here at work. Let's just say I'm glad I didn't lose much of anything. Lost some power below 3500 and gain the same amount between 3500-4500, which gave the false impression there is a nice bump from 3000 on up by the seat of the pants. Top end was unchanged. Given the amount of labor and cost involved (header install is a PITA), it is the "one mod" I would unequivocally pass up on if I had the chance of a redo.
The OEM exhaust manifold, albeit not the prettiest thing, isn't as lousy as it looks. Upgrading to after market headers for the G35 will not net you the uniform gain across the board as shown in the Alpha Works dyno. In fact such a characteristic response is almost always due to the ECU, a tell tell sign that the ECU reset procedure before each dyno was not performed. Intake and exhaust tuning has much to do with resonance as simple flow increase. As such, the gain (if any) will almost never be uniform. That Alpha Works dyno plot is best ignored.
Also did you happen to do any pulls before the headers that might show a change in a/f?
The pre/post dyno plot complete w. AF, as promised.
As you'll see, the pre/post curves were more or less the same, which was unfortunate but also a relief. Again the lost and gain between 2500 - 4500 gave the sensation the headers are really doing it's thing. Not the case really.
AF retune was not performed because, as you can see, it narely even budged. You can dismiss the one anomally for the 1st half of DC run #1. ECU was lethargic transitioning from closed- to open-loop operation.
An ECU retune was eventually emposed to combat the funky AF hike @ 4000rpm, a trait that was observed on many stock G35 and 350Z. No appreciable power increase were noted after the retune.
Tony @ Motordyne have also dyno'd his DC Sports based Top Speed headers (I believe). It was not entirely shocking when his curves turned out to be a mirror image of mine, exhibiting the same lost and gains. Overall, no gain for him either.
Sloppymax,
I can't comment on the Hot Shot headers. It is plausible they are not based on the same DC Sports design, that so many companies seemed to have ripped. If your AF did change significantly then that's far more encouraging than mine.
As you'll see, the pre/post curves were more or less the same, which was unfortunate but also a relief. Again the lost and gain between 2500 - 4500 gave the sensation the headers are really doing it's thing. Not the case really.
AF retune was not performed because, as you can see, it narely even budged. You can dismiss the one anomally for the 1st half of DC run #1. ECU was lethargic transitioning from closed- to open-loop operation.
An ECU retune was eventually emposed to combat the funky AF hike @ 4000rpm, a trait that was observed on many stock G35 and 350Z. No appreciable power increase were noted after the retune.
Tony @ Motordyne have also dyno'd his DC Sports based Top Speed headers (I believe). It was not entirely shocking when his curves turned out to be a mirror image of mine, exhibiting the same lost and gains. Overall, no gain for him either.
Sloppymax,
I can't comment on the Hot Shot headers. It is plausible they are not based on the same DC Sports design, that so many companies seemed to have ripped. If your AF did change significantly then that's far more encouraging than mine.
Last edited by THX723; Jul 31, 2007 at 04:34 PM.
yes, under hood temp did take a hike from the now missing heat shields. I double insulated my clutch line just in case. What I really need is to fab a set of custom heat shields. However, after countless of track events ... I have yet observed any ill effects. *knock on wood*
Last edited by THX723; Jul 31, 2007 at 04:33 PM.
Joined: Feb 2006
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From: Southern Cali --> 818
THX723, thanks for the info/review.
One of the reasons I think im going with the Strup SS headers is because of my doubts about any performance gains, unless its crawfords headers. Taking a risk on a cheaper product makes me feel better, rather than spending 200 more for the DC sports SS headers.
Anyhow, these headers would be beneficial for my future goal, which is a Vortech SC.
I'm hoping I have better luck with NA header power; the cipher logs will tell alot when the time comes.
.
One of the reasons I think im going with the Strup SS headers is because of my doubts about any performance gains, unless its crawfords headers. Taking a risk on a cheaper product makes me feel better, rather than spending 200 more for the DC sports SS headers.
Anyhow, these headers would be beneficial for my future goal, which is a Vortech SC.
I'm hoping I have better luck with NA header power; the cipher logs will tell alot when the time comes.
.
You're quite welcome skater! 
I wish you the best and let us know how they work out.
As mentioned above, I'm really not expecting the Stupp unit to perform any different than the DC Sports design it was based on.
Perhaps by adding Vortech to the equation will the increase in flow finally deem these headers worthwhile. If I were you, I'd holding off until you have the Vortech installed then peform a proper pre/post header analysis.
I wish you the best and let us know how they work out.
As mentioned above, I'm really not expecting the Stupp unit to perform any different than the DC Sports design it was based on.
Perhaps by adding Vortech to the equation will the increase in flow finally deem these headers worthwhile. If I were you, I'd holding off until you have the Vortech installed then peform a proper pre/post header analysis.
Headers will do little good without a reflash or other fuel mix tweak. I was in the low-mid 14's after header install and the ECU was trimming timing due to detected knock I couldn't even hear, but showed up on the dyno datalog. After reflash by Technosquare, it was right on the money at 13.2 and the power difference was about 9 HP and 11 TQ. I will post the dyno sheets if I can find the CD (been over a year ago).
Bottom line? Don't expect much after just bolting some headers on, maybe even see a loss due to lean/timing pull. The ECU is very narrow minded and cannot deal with flow outside a set range. But clearly there was room for flow improvement on the manifolds since the '07HR uses basically an OEM header.
Bottom line? Don't expect much after just bolting some headers on, maybe even see a loss due to lean/timing pull. The ECU is very narrow minded and cannot deal with flow outside a set range. But clearly there was room for flow improvement on the manifolds since the '07HR uses basically an OEM header.
ballisticus,
The notion of ECU retune for optimize gain is well accepted. It's the right thing to do.
However, your gains from Technosquare ECU flash more than touched up on just the AF. Included in the reflash are a slew of tweaks including ignition timing. All of which have been shown to gains ~10hp on a bone stock car (read that as no headers involved). So the question to ask yourself is, of the 9hp you have gained what part of that was from the headers or simply the ECU tweak?
The point is unless you have performed an ECU reset prior to your baseline dyno, it is simply all too likely you have got yourself a "false low" as baseline. Please read here to get a whiff of what all the fuss is about regarding ECU reset before Dyno runs.
Fact is I have also addressed the AF and only the AF after all my mods. There was no appreciable gain from the practice. We're not dealing with Force Inductions where AF lays a greater role on allowable timing advance and lots of power to be unlocked.
The notion of ECU retune for optimize gain is well accepted. It's the right thing to do.
However, your gains from Technosquare ECU flash more than touched up on just the AF. Included in the reflash are a slew of tweaks including ignition timing. All of which have been shown to gains ~10hp on a bone stock car (read that as no headers involved). So the question to ask yourself is, of the 9hp you have gained what part of that was from the headers or simply the ECU tweak?
The point is unless you have performed an ECU reset prior to your baseline dyno, it is simply all too likely you have got yourself a "false low" as baseline. Please read here to get a whiff of what all the fuss is about regarding ECU reset before Dyno runs.
Fact is I have also addressed the AF and only the AF after all my mods. There was no appreciable gain from the practice. We're not dealing with Force Inductions where AF lays a greater role on allowable timing advance and lots of power to be unlocked.
Last edited by THX723; Jul 31, 2007 at 10:07 PM.
again, i am speaking from previous experience but on my previous vq i was happy after the system was tuned. i ended up purchasing a walbro and an adjustable fpr. what i found was that i could influence timing but bumping up the fp and backing it out with my piggyback (vafc2 yes it will work on other cars than hondas, just dont tell the hondas boy or they get all upset). on the dyno, the timing showed additional gains above the headers & the initial tuning. this is obviously to a certain point before the ecu begins rejecting the change. just something to think about for those that want to keep it NA.
Originally Posted by THX723
ballisticus,
The notion of ECU retune for optimize gain is well accepted. It's the right thing to do.
However, your gains from Technosquare ECU flash more than touched up on just the AF. Included in the reflash are a slew of tweaks including ignition timing. All of which have been shown to gains ~10hp on a bone stock car (read that as no headers involved). So the question to ask yourself is, of the 9hp you have gained what part of that was from the headers or simply the ECU tweak?
The point is unless you have performed an ECU reset prior to your baseline dyno, it is simply all too likely you have got yourself a "false low" as baseline. Please read here to get a whiff of what all the fuss is about regarding ECU reset before Dyno runs.
Fact is I have also addressed the AF and only the AF after all my mods. There was no appreciable gain from the practice. We're not dealing with Force Inductions where AF lays a greater role on allowable timing advance and lots of power to be unlocked.
The notion of ECU retune for optimize gain is well accepted. It's the right thing to do.
However, your gains from Technosquare ECU flash more than touched up on just the AF. Included in the reflash are a slew of tweaks including ignition timing. All of which have been shown to gains ~10hp on a bone stock car (read that as no headers involved). So the question to ask yourself is, of the 9hp you have gained what part of that was from the headers or simply the ECU tweak?
The point is unless you have performed an ECU reset prior to your baseline dyno, it is simply all too likely you have got yourself a "false low" as baseline. Please read here to get a whiff of what all the fuss is about regarding ECU reset before Dyno runs.
Fact is I have also addressed the AF and only the AF after all my mods. There was no appreciable gain from the practice. We're not dealing with Force Inductions where AF lays a greater role on allowable timing advance and lots of power to be unlocked.
Every car is different. I think it is safe to say the the typical header design for the VQ was not really intended to produce peak HP #'s for dyno bragging rights. Most of them are designed for flat mid-range torque production and I could definitely feel that even before the reflash.
So I guess what I am saying is that the dyno sheet doesn't tell the whole story if we're talking only peak #'s. And anytime you can get a design that is within 1/2" runner length between cylinders and a good merge collector, its a good thing for scavenging/wave tuning. But couple that with a mis-matched catback with poor velocity characteristics and yeah, the header could actually make you slower as it will magnify the poor situation. Mine seem to work well with the Stillen and test pipes, but others may not. It all has to match up to get the wave timing right.
I guess I should have clarified what I would want out the header being 10-15whp. I am concerned with under the curve power. I could care less what the peak is unless it feel short of the average graph for the same mods.
Originally Posted by ballisticus
Every car is different. I think it is safe to say the the typical header design for the VQ was not really intended to produce peak HP #'s for dyno bragging rights. Most of them are designed for flat mid-range torque production and I could definitely feel that even before the reflash.
So I guess what I am saying is that the dyno sheet doesn't tell the whole story if we're talking only peak #'s. And anytime you can get a design that is within 1/2" runner length between cylinders and a good merge collector, its a good thing for scavenging/wave tuning. But couple that with a mis-matched catback with poor velocity characteristics and yeah, the header could actually make you slower as it will magnify the poor situation. Mine seem to work well with the Stillen and test pipes, but others may not. It all has to match up to get the wave timing right.
So I guess what I am saying is that the dyno sheet doesn't tell the whole story if we're talking only peak #'s. And anytime you can get a design that is within 1/2" runner length between cylinders and a good merge collector, its a good thing for scavenging/wave tuning. But couple that with a mis-matched catback with poor velocity characteristics and yeah, the header could actually make you slower as it will magnify the poor situation. Mine seem to work well with the Stillen and test pipes, but others may not. It all has to match up to get the wave timing right.
Originally Posted by trey.hutcheson
I think that's interesting, because you and I have/had almost the exact same mods, including brands. I didn't experience any gains from my headers. However, I put the headers in when I had the engine replaced, so I never had a baseline on the engine sans headers. Regardless, with the same ecu, the new engine+headers put down a consistent 10hp/tq less than the older engine and stock manifolds.
Hmmm. 6MT revup cam profile/variable exhaust timing no like headers? My "detuned" 03 woke up pretty well from them, so maybe its a matter of velocity/valve timing mismatch again. To do it right, the aftermarket would have to design/tune a different header for each VQ variant. There are so many different combinations of aftermarket stuff bolted up its no wonder the results are generally poor. Its a crap shoot.
Variable valve timing really complicates things because the ECU is constantly trying to bring the torque and mix where it has been told to be. It basically "tunes out" the effect of the increased flow. No reflash/piggyback that I know of deals with valve timing re-optimization.
Last edited by ballisticus; Aug 1, 2007 at 06:30 PM.
Originally Posted by THX723
yes, under hood temp did take a hike from the now missing heat shields. I double insulated my clutch line just in case. What I really need is to fab a set of custom heat shields. However, after countless of track events ... I have yet observed any ill effects. *knock on wood*