MadDog

Has anyone seen results of combining a header and a high-flow cat? There are results around for each of these components individually, but I haven't seen any for the combination. If the stock units are both equally restrictive, you wouldn't see much gain from changing only one since the restriction from the other would then dominate the speed of the gas flow. But changing both might give better results.

Fanman

About the only people I have seen swap out the complete exhaust system is Racing Beat & they said they got about 10-12 hp with a full race exhaust system. Other than that I haven't heard of anybody getting too many gains from the header. Most of the hp gain comes from the removal of the cat.

XDEEDUBBX

removal of the cat completely is about 5-7 hp....

brillo

The real issue appears to the the exhaust ports, as RB pointed out in that a full header/mid pipe/cat back wil only net you 10-12whp. Aside from removing the cat, I wouldn't invest in headers unless I had ported the engine, its just not worth it. Racing Beat has fabed some prototype headers, but since they didn't get any meaningful gains, I think they shelved them for the time being.

Nemesis8

iTrader: (3)

You got me started again :D

Headerless in Seattle I will have one, one day - I will :D

I have two vids from NeedForSpeed hosted of the RE Amemiya Header, R-Magic High Flow CAT, and HKS Catback on my server.

3.5MB
3.0MB

Someone get the Feed Equal Length Runner Header. OK, I'll get it this summer - just got a raise. :p

https://www.rx8club.com/showpost.php...3&postcount=40

Mzdarx8

That sounds so Good!!

I would love to get a header but decided on the Greddy turbo after seeing the
performance. 250-260 whp on a stock car? That's enough for me!

Congrats on your raise$$$

Fanman

More like 230-240 whp.

Mzdarx8

Not from what i saw at Pettit and Japtrix and there dyno's on customers cars.
Japtrix had a race pipe and rev8 exhaust from what i was told. There dyno
sheet i saw was 268 whp at 8200 rpm. Pettit was word of mouth that they
just dyno'd a customers car with only Greddy exhaust at 260 whp.

It is hard to believe that just an exhaust can give you 20hp.

Greddy claims 60whp on a stock car. This would put a stock 180whp at 240whp.

I know there are some 8's with less whp. I just wish the best for all of us!!

Fanman

Most of the people on this board have been getting about 230-240 whp. 60 whp is about right, but many RX8's dyno from about 170 to 185 whp. Philodox dynoed from 180 to 241 whp, but realize he had already had the Borla exhaust when he dynoed at 180 & 241 whp. I had 180 whp with the Rev8 exhaust & hi-flow cat & I dynoed at 232 whp, even though I am a lb. down on the stock settings (6lbs. throughout the rev range, & 4 at the top, when the stock settings should be 7/5). There was one that dynoed at 273 whp in PR, but he was running dangerously lean. For the bolt on part of the kit you are really looking at around 240 whp. Might get a little more with some on the bolt ons, but 20 hp from a cat back is ridiculous. 60-65 whp (which is realistic) will put you at where I said around 240 whp. If you want more you can tune it (& with some of our kits, just to get up to their claimed stock levels) a bit, but that is not really bolt on then.

Mzdarx8

Thanks fanman,

I still need to dyno my 8 cause i still don't know what i got??

MadDog

So how much are these bad boys these days?

If a header+high-flow cat is netting 10-12 whp, that's not too shabby. (especially for those of us wishing to stay N/A. I seem to recall seeing some posts about the best improvement on the ports just being a little smoothing on the exhaust ports. I think the gist was that a full porting job on the exahust wasn't worth the effort. just smoothing the edge a little bought most of the gains. If 10whp is correct, then I'd get a header + cat if the header could be had for $400.


-MD

Mzdarx8

I think they start around 900.00 and go up. Plus labor!!

Lot's of $$ for the hp.

Fanman

Note that is around 10-12 hp (they did not say wheel hp), and that was not just the header & straight pipe, but the FULL race exhaust (incl. the cat back part). None of the current headers on the market even come close to that price. Most are 2X & even 3X that price.

Mzdarx8

Excuse me, 1329.00 for the Re-Anemiya Header.

Not to bad!! Not 2x or 3x

http://www.mazdaparts.com/ProductDet...000-1112606399