danielm

Hi all I am I own a shop and have a customer that needs a set of headers made for his RX8 and I am having a hard time coming up with the numbers to design a proper system.

My question is what would you guys say the RX8 motor compares best too size and power wise... I was thinking ether the S2000 or the STI (not looking at the turbo just motor size) I basically need something for the bore and stroke everything else I can figure out.

Thanks!

tiggerlee

Why headers?

danielm

That's what the customer wants, it's up to him.

Brettus

iTrader: (2)

most compare it to a 2.6 L N/A engine

TeamRX8

iTrader: (25)

you can't figure anything out as the piston engine header rules don't apply

mikeschaefer

There's no port overlap if that helps

Chrissss

Headers on an RX8 are essentially worthless due to the exhaust port design. At present all attempts at designing headers are only giving 2 to 3 whp.

Do a forum search on headers and pay particular attention to theory discussions by Rotarygod.

Chris...

danielm

Thank you guys very much!

TeamRX8

iTrader: (25)

if you insist on a header use 1.75 - 2" primaries, IMO the length or need for multi-tubes is irrelevant on this engine due to the lack of overlap. I've proven that a simple lightweight, hi-flo version of the OE manifold works, multi tubes = more radiant heat .... more important is the ability to retune the fuel/ignition software, you won't get the full benefit without it

https://www.rx8club.com/showpost.php...0&postcount=51

Brettus

iTrader: (2)

Hmmmm - does it give you a small power increase from about 2500rpm right through to the redline

TeamRX8

iTrader: (25)

for the 1000th time, all that same equipment was installed for every dyno run

Brettus

iTrader: (2)

just trying to get you to narrow it down a bit so we can all benefit from what you have learned .

danielm

thanks guys, after doing a lot of reading i think I have my design figured out. I will post some pics for you guys to check out.

danielm

Here is what i came up with. The one on the left is the original design; the one on the right is what I came up with. An engine dyno in the next couple of days will show what kind of power this thing is going to make.

Oh and don't mind some of those welds too much, this is a prototype and final one will have all the bends programmed on my bender.

Brettus

iTrader: (2)

its not for an RX8 is it ?

The Ace

You are worried about clearance, aren't you ?

Three exhaust ports, this *must* be an RX8 header....although I'm puzzled as to the purpose of the second design (longer runners). Maybe it has something to do with exhaust gas velocity ?

danielm

This is for an open wheeled car, which is using an RX8 motor... that is why I have so much more room to work with.

All the designs I have seen, for this motor, use big short pipes and don't gain much power. I wanted to try something completely different, based on numbers I cam up with.

I was able to pull an extra 30whp and 40wtq out of an IS300 with a full exhaust system (headers, exhaust all that good stuff) more info can be found on my site http://www.mazzurisuper.com if anyone is interested in reading some more about it.

I will know if this was a complete waste of time or not very soon.

SlayerRX8

The difference is that factory parts for the RX-8 are much better tuned than factory parts for the IS300. NA gains on the IS300 are much higher.

TeamRX8

iTrader: (25)

nice work, but it's all in vain. In an unported zero-overlap timing Renesis you won't make any more power than anyone else, and then most of it will only be found with re-tuned fuel/spark software

Astral

He's probably running retuned fuel/spark though, if it's on an openwheel racer.

grinn253

Hi there!

Nice work, and glad you took your time to design/create another header option for the Renesis, despite some comments that power increase will be minimal. If anything, perhaps you can simply provide another option for RX-8 headers than the current vendors.

Good Luck once again, laters!
Edgardo

Turblown

You're definitely moving in the right direction with the design. I've wanted to find a customer who was willing to pay to keep playing...