Just got mine today, and figured with all the hubbub about the collector diameter, I'd take some pics before I put it on. To me, it looks more like 2 1/8" vs 2.5"
www.geocities.com/motorcity/7281/header1.jpg
www.geocities.com/motorcity/7281/header2.jpg

The geoshitties sponsored links don't seem to be working, so you might have to copy/paste the links, guys.


[Modified by eternal21, 11:13 AM 10/14/2001]

 

that's b/c what you're measuring is a resonator inside the header...remove it and you'll have a 2.5" collector

 

It's an anti reversion chamber

 

my JDM ITR header and Carsound 94006 (supplied by SMSP) rocks!
Much better performance that the sorry Comptech, specially when my VTEC hits at 5k rpm!!!
Also, did not feel any loss in low end. I will have my car dynoed and compare against the other header next week!!

 

resonator, anti reversion chamber....same **** hey cut me some slack, I was supposed to be sleeping when I wrote that

 

I was already thinking about having this done when I have the header rewelded on the outside and port the runners, but has anyone done it yet (remove the anti-reversion chamber)? What kind of effects were noticed, and were there any hp gains or losses?




[Modified by eternal21, 11:07 AM 10/14/2001]

 

I did not bother to remove the chamber. I already gained about 1/4" in diameter compared to the Comptech header. I was afraid to go too big and lose power. That's why I stayed away from a "true" 2.5 in. collector header like the DC JDM 4-1. Also, if you look inside the collector, the header tampers (SP?) to the same diameter as the anti-reversion chamber before it gets to the chamber. I am not 100% sure but I don't think there would be more than maybe 1 whp gain at the top at the cost of probably some HP in the low end.

 

And this leads directly into another question: anyone running 2.5" b-pipe w/Toda Bs on a engine running 12.5:1 or higher compression, or are you guys mostly sticking w/2.25" b-piping? I know the cams like to breathe, but I'm wondering will there be any loss on low end (torque, hp) b/c of lack of backpressure due to the diameter of the piping.

I kinda have this theory that due to the anti-reversion chamber and the lack of a true 2.5" collector that the a.v.c. acts as a minor bottleneck that will cause some backpressure, so loss on the lowend will be minimal if using a 2.5" b-pipe.

Thoughts or suggestions?

 

Do you search on backpressure.

 

I ran the 2.5" pipe when I still had the b16 with spec B cams. Made 178 whp with just bolt-ons. JDM Mugen 4-1 header, 2.5" b pipe, Mugen twin loop muffler.

 

Yo toda im from clubsi .. you making 210 whp and 140lbs of torque at the wheel with toda products?

 

goes to find dyno sheet....