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CTSC and header options

Joined
21 February 2004
Messages
674
Location
Amsterdam
I am running the first CTSC version and have done so with Comptech headers. Since we are rebuilding my car, we are putting the Comptech headers on my dads NSX. I will get a new pair.

I have a Super Taitec C3 Model 2 exhaust, so maybe the Taitec headers would make the set complete. But I am also reading many good things about the SOS headers. For some reason (maybe just looks :D) I really love the GT-ONE headers, but I can't justify the price difference compared to the other ones (or are the THAT good?). Then there are of course the CT headers.

What other options are there? Which one is the best for a supercharged engine?
 
I guess you can't go wrong with the headers you've mentioned. As the labor involved is quite high I'd get some low-living quality headers. I for myself got a CT header as I'm also CTSC and the quality is very good.
 
I would not choose headers based on looks, unless it's a show car that spends its time sitting over a mirror.

If you really want top notch, Mugen.
 
Header design for an N/A motor is much more critical than in a supercharged engine. In an NA motor you always have a compromised decision to make; torque down low or high hp up top. This is when concepts such as diameter sizing and stepping of diameter, long tube design, collector size and length, 4-2-1 vs 4-1 design (in a 4 cyl) all play a critical factor. However, in a supercharged designed you achieve the magical exhaust flow velocity of 240-260 ft/sec much much quicker therefore diameter is KING and all this other stuff is much less important if not virtually irrelevant.

In the NSX you have additional constraints. The transverse V6 design makes it difficult to package a proper collector in the front bank (it'll scrape all over the place if large diameter or stepped primaries are used). It is also difficult, if not physically impossible, to have a equal length 6-3-1 design of some sort to maximize scavenging and/or mid range torque.

Most of the good aftermarket headers have a 2.25" diameter secondary pipe (after the collector). Which is plenty big enough up to about ~500hp. This is assuming you don't have a restrictive Cat in place and/or a restrictive exhaust muffler in place. The whole exhaust system has to be designed as one system. This is also why I think you will gain more power if you have independent mufflers for each engine bank. Like the common "parallel" exhausts on here. They don't sound the best but they are more functional for a CTSC imho.

In a 4 cyl these are some basic guidelines on secondary pipe sizing. If a 2.25" ID can support 4 cyl @ 210 crank hp. It can certainly support 3 cylinders at the same relative hp with room to spare. This is assuming your CTSC is pushing approx 400whp.
2-1/4" up to 210HP @ the flywheel (about 180-185 whp)
2-3/8" (60mm) up to 235HP @ the flywheel (about 200-207 whp)
2-1/2" up to 265HP @ the flywheel (about 225-235 whp)
2-3/4" up to 325HP @ the flywheel (about 275-285 whp)
3" big for big HP (Forced Induction: > 275 whp)

btw.. I use the Comptech Headers and will stick with them until I go back to NA which will be a completely different ballgame. For now, i'm having a custom made exhaust system in which everything after the headers are completely new while also trying out some new concepts. Thanks also for the Nato band recommendation for my sub! I love it and have been wearing that watch so much more now.

EDIT: Going thru the math. It's better to go with a 2.5" pipe after the collector for a 400whp V6. Time for some new headers...
 
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It is also difficult, if not physically impossible, to have a equal length 6-3-1 design of some sort to maximize scavenging and/or mid range torque.

This is exactly what the GT-one header does. The only one to do so.
 
This is exactly what the GT-one header does. The only one to do so.
Unfortunately for us this is incorrect. The GT One headers may be equal length but they are a 3-1 x 2 not a true 6-3-1. You would need 2 pairs x 2 pairs x 2 pairs of primaries which merge into one.

For example:

"6" primaries
1 2 3 (front bank)
4 5 6 (rear bank)

"3" Tri-Y or is this Quad-Y lol?
where 1+2, 3+4, 5+6

"1"
collector that merges the 3 into 1

I have not studied the firing order enough to know which pairs are correct to time the valve overlap properly to promote scavenging nor am I an expert. Like I said.. for SC engines.. this all seems trivial. It might not even be possible with our V6.. When I go NA i'll spend more time on this.

The GT-One headers are just 3-1 but the are equal length which is a plus.
IMG_0131.JPG


vs. a Tri-Y from a 4 banger
hitech3%5B1%5D.jpg

Like I said.. it might virtually be impossible. I don't even know how to package this in our V6.
 
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Yes, I don't see how what you are saying can be done on a transverse v6 or how much benefit it has. But the GT-one is 6 equal length pipes. No other header has this.

But I am probably going to sell mine as I am going twin turbo to match my username. :biggrin:
 
I thought the Taitec is too.
GT One, Fujitsubo, Taitec, and SOS (though I don't think they ever produced them?) are all equal length (you're not special Dave lol). Again, i'm not sure how much benefit equal length has in a 3-1 design given our firing order. I have not studied the topic extensively but i'm certain their benefit is of little impact and likely negated in a SC application.

Turbo, if you decide to live up to your name... you just want the turbos as close to the cylinders as possible. How everyone does it (except SOS Twin) puts them way down stream. For packaging it's necessary but not ideal. I'd be curious how DDozier did his setup.
 
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GT One, Fujitsubo, Taitec, and SOS (though I don't think they ever produced them?) are all equal length (you're not special Dave lol). Again, i'm not sure how much benefit equal length has in a 3-1 design given our firing order. I have not studied the topic extensively but i'm certain their benefit is of little impact and likely negated in a SC application.

Turbo, if you decide to live up to your name... you just want the turbos as close to the cylinders as possible. How everyone does it (except SOS Twin) puts them way down stream. For packaging it's necessary but not ideal. I'd be curious how DDozier did his setup.

I do not want to derail the thread. But it will be ddoziers setup.
 
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