I posted a while back with no responses that anybody has done this. I had a shop modify the collector on a stock exhaust. We went to a 2.5" collector, flex pipe, and exit. Total cost including buying another stock header was $180. About $140 less than a dc sports. I dont know if anyone has dyno'd just header vs stock , but I plan on dynoing both pipes to see if I gained anything at all.
WOW thats a good mod. I been considering to do this on my DC CC header and putting a bigger collector on it.
Can you describe better what parts you used ...where did you get them and so on. Most important time it took to do this mod.
Have you felt any difference with the Butt dyno?
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Still Single and employed but hate my job! Nothing has changed.
I'm not really sure if this will do much considering the sizing/merges of the stock piping. I can't tell you for sure, but the primaries or the secondaries just might not be able to flow enough to utilize the new collector. Though I wouldn't be too suprised if you do see some gains from the mod.
i dont know what the difference needs to be, but the secondaries are (2) 1.7" diameter tubes. So thats a total flow size of 3.4". I dunno if 2.5" is too big or not, we'll see. I know inside it looks MUCH bigger if you look down the tube with a flashlight. The inside of the stock pipe is sooo restricted I just can't see not gaining anything. All I'm hoping for are the 3 or so hp that everybody else gains with aftermarket headers.
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2001 Pearl White Base 5sp *SOLD*
2004 EBP SRT-4
C'mon man, you do this and don't remember geometry?
A = pie * r^2 So for the seconadies it would be ~2.3 in/sq each
Your collector would be ~4.9 in/sq so the collector is quite a bit larger than the secondaries. The only thing I'd worry about is that the flow becomes compromised by the larger collector on the stock header and you loose velocity when it hits the collector and possibly gets held up in there. If anyone were to try this in the future it might be more benificial to extrude hone the stock header. Though I'd like to see a dyno once you get one!
wait im confused by your math, secondaries are 1.7" dia so thats 9 in/sq per secondary x 2 is 18 in/sq. Then my new 2.5" collector is 19.6 in/sq so its slightly larger, you are right. It might be too much flow. hehe thats almost like a 4-1 as far as flows go. We'll see
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2001 Pearl White Base 5sp *SOLD*
2004 EBP SRT-4
3.14 (approx for pie) * .85"^2 (1.7" / 2 = .85" as the radius) = 2.3 sq/in * 2 ports = 4.6 sq/in
collector:
3.14 (pie) * 1.25"^2 (2.5" / 2 = 1.5" as the radius) = 4.9 sq/in
So you have around a 8% size difference in just the cross cut, this doesn't take into account the volume. But I don't know enough about header theory to say what this exactly will do.
lol, its not even on the car! I just got it 2 days ago and the closest dyno is an hour away! And UPS lost my hondata gasket so the car won't even be running til tuesday!
i have a kamkaize header for sh which is jet coated and has a 2.5" collector if anyone is interested i will sell for $185 shipped to your door and it has few scratches on the downpipe..
Im interested in doing this too, but would like to see your result!! Where are the dyno plots???
Difference is I have a jdm downpipe that is larger then USDM.
I was going to put a 2.5" collector (its 2.25" JDM stock), 2.5" flex pipe going to a 2.5" high flow cat, and then to a 2.25" catback (2" now).
This should be perfect me thinks...
honestly.... i sold the lude before I ever dyno'd the results. There wasn't a dyno in town at the time I even bought my own wideband to tune my VAFC.
I still have the B pipe in my garage, I am curious what the results might be too. If somebody is willing to use it on their car and dyno the results for myself and us to see. I will sell it to you for free just shipping costs which should be about $15 I'd guess. But only somebody who plans on carry on my experiment and at least dyno the car sometime with it on.
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2001 Pearl White Base 5sp *SOLD*
2004 EBP SRT-4
i should be on a dyno at some point in the near future after i figure out what kind of exhaust i'll be running, and after getting the VAFC installed/tuned.
Originally posted by trulegend i have a kamkaize header for sh which is jet coated and has a 2.5" collector if anyone is interested i will sell for $185 shipped to your door and it has few scratches on the downpipe..
....says the guy w/ a -1 trader value....
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