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-   -   Header advice! (https://www.rx8club.com/series-i-aftermarket-performance-modifications-23/header-advice-232281/)

chance red04 04-21-2012 03:51 PM

Header advice!
 
Looking to get some headers for my car. And was wondering which one I could get the most power gains out of for a decent price

paimon.soror 04-21-2012 04:12 PM

Going to be blatantly honest here, but nothing and neither.

A header (only one ;) ) won't produce much gains without significant modifications to the rest of the exhaust system. Granted that equal length tubes are "better" for a typical engine, there isn't too much performance to be gained by a standard length header. BHR is working (as far as I know) on a long tube header system that actually provides benefits .

You can look around and find some generic header on ebay, or the racing beat, or even OBX... honestly you arent going to gain HP that falls in line with the cost, if any HP at all. You may get a better exhaust note.

Also without knowing your current mods, you really wont get any accurate responses.

RIWWP 04-21-2012 04:15 PM

An aftermarket header with the mid/cat and cat-back stock will produce basically no gains. The better flowing the two rear pieces are, the more effective a header will be. The only gains are from removing restrictions, and only once the OEM header is the most restrictive point will upgrading it really make an impact. The cat/mid is usually the most restrictive. The OEM cat-back allows the exhaust to decelerate too quickly before exiting, creating a restriction there as well. Remove both of those problems and then the OEM header will be the poorest performing item, and upgrades will do something.

As with anything that is designed to flow from one item to the next, a set that is designed to work together will be superior (even if only slightly) to mixing and matching between brands/makes/etc...

olddragger 04-22-2012 08:46 AM

even in removing the header back restriction ( cat excluded)--at the present na power level a tubular header for street use doesnt make sense. If you want to totally redesign the header and midpipe areas--yes you can gain a little--maybe 10-15 hp in the mid/upper ranges--but it is expensive and if you dont get it exactly right with the proper sizes and angles--then all that money and time will be for nothing.
IMO its better really just to develop a slightly better flowing log manifold?
Zero overlap is zero overlap. I havnt heard of any reversion being noticed at the Siamese port either?

PhillipM 04-22-2012 09:05 AM

I don't think there's even room to get the length you want into an RX-8 without chassis surgery tbh.

olddragger 04-22-2012 10:47 AM

never underestimate a man with a sawzill, angle grinder and weilder!

PhillipM 04-22-2012 11:20 AM

That's how I built mine :lol:

But I swapped the sawzall for beers.

bse50 04-22-2012 12:07 PM


Originally Posted by olddragger (Post 4245567)
IMO its better really just to develop a slightly better flowing log manifold?
Zero overlap is zero overlap. I havnt heard of any reversion being noticed at the Siamese port either?

It takes 10$ of dremel bits and a hammer\chisel after all...


Originally Posted by PhillipM (Post 4245582)
I don't think there's even room to get the length you want into an RX-8 without chassis surgery tbh.

There's enough room to merge the headers where the oe cat is. The problem is in the engine bay... the bends are narrower than one would like them to be but still, it werkz.


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