I have been looking into a set of headers for sometime now and I am constantly hearing about how people are seeing very little to no gains. With this being said i have yet to find one dyno graph of a base run and then a run after the header install...so im trying to figure out where people are getting these asumptions from.

I am trying to find a dyno graph for stillen headers, but have yet to find one - it's driving me nuts, stillens website doesn't even have one.

So can anyone provide a dyno graphs for post header installs? It doesn't matter which brand of headers they are just as long as it is some type of graph.

-Sean

 

I found this on a website - they are alpha work headers, but i don't know how accurate the graph is...

-Sean

 

This was my pre and post crawford headers. I posted the results a few months ago. This is on the Church dynapack in Socal. Stock 6MT non rev up motors get about 255. My car's a 5AT FWIW.

 

Do HFC/TP with your headers and you'll be loud and quite a bit faster--

FMU would really tie it all together nicely.


the more $ the more vrrommm

 

results in 2005 are not comaprible to those obtained in 2007 (as per what it says on your graph)

for an accurate comparison you need to dyno within 24hrs on the same dyno and while the weather conditions are exactly the same

 

I agree, ideally the car would be left on the dyno, but seeing as how it took an entire shop 2 days to get the Crawfords installed, I don't think I would ever have had a within 24 hr dyno comparison. It was the same dyno, though. The weather can change even in 24 hours. Take it or leave it.

 

Cool, thanks for the graph - anyone have anymore graphs?

-Sean

 

the sae correction take weather inputs into equation so rule that out. one of the biggest factors would be the number of pulls before using a particular graph.

 

Some of these dyno's look like they're from the manufacturers.

I'm looking into the Strup headers; I can't justify not paying for a great product when it only cost mid-400's

I was thinking about DC's, but im going to take a chance on the Strup stainless steel when the time is right.

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i would rather see an individuals dyno. i know everyone wants the highest numbers but someone selling a product is more inclined to use dyno tricks to show bigger differences.

 

Exactly my point

The best dyno anyone can use is called the drap strip

But if numbers are so important, assuming the before/after dyno is taking place on the EXACT same dyno @ similar conditions, I would expect anywhere from 7-12 rwhp & 10-15 rwtq depending on the RPM/powerband.

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i will hopefully be getting my baseline 1/4 times this weekend as well. then buy some headers, get them installed then get back to track before it closes in the fall.

 

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 that is 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, Top Speed, Alpha Works, etc.), so I wouldn't expect any better from them.

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 (if we can assume any shady business going on), 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.

 

Is there any weight difference do you know? I am pretty sure the exhaust is unspring weight so every pound in that department will help. I know a good set of HFC's will weigh about 15 pounds less than the OEM cats. Do you know weight differences on headers - if any?

-Sean

 

Sean,
"Unsprung weight" refers to mass that cannot be controlled by the suspension springs and dampers; that would be everything that is not attached to the chassis (i.e. tires, wheels and brakes). Exhaust/headers/cats are very much part of the chassis and therefore part of the "sprung" family. Saving weight there is not as cool as the former, but still a good thing.

There's not a significant weight saving w. header upgrades. OEM catalytic converter do weight quite a bit, so there's some saving to be had by replacing them with high-flow cats or especially test pipes.