Dense question?

[Mosi]

Whats the benefit in spending a rake load of cash on one of these fancy shiny exhaust manifold thingies that everyone keeps bangin on about ?? - my standard one looks a bit poo these days, so might be one of these shiny one's if they are any use ??

Answers please ?

[AndyF_RSX]

Mosi,
Same reason you spent a fortune on a shiny big exhaust for your mota.... Better gas flow through the manifold and exhaust system will mean more air can get into the engine and therefore more power. You may also be able to get a 'tuned length' manifold which utilises extra scavenging effect to improve things even further. It does this because as the exhaust gases pass down through the manifold, when they come to a restriction, you will get a reverse pressure pulse sent back towards the engine. If you time the return of this pulse correctly, it can be turning away from the engine at the same time as the exhaust valve next opens and so gives you even more suck from the exhaust to pull in extra fresh air. The only problem is that the exhaust can only be tuned to one particular rpm and so you get a gain at a certain point. This is why cars like the Ferrari's have variable length exhaust manifolds so they can make use of this effect over a larger rev range.

Basically then, an uprated manifold SHOULD provide better exhaust gas flow and so give you more power. A tuned length manifold can help even further but only at a specific rev range and if you want to be really flash, try and find a variable length exhaust manifold and you'll be laughing (but also very poor!!!!0

Hope this helps

Andy

[Mosi]

Andy,

Ta very much - an informative and concise answer as ever from you ;) cheers.

Are they REALLY worth the beans ?

And what sort of dough are we looking at + what options are any good ?

I've heard that some after market options offer next to bugger all improvement and in some cases at certain rpm, actually lower power!

[Lightspeed]

Just my personal opinion....

No - not without a substantially different (bigger!) turbo.

Mitsubishi did a very good job with the standard exhaust manifold.

Why not buy a nice new heat shield for the standard manifold instead and save the pennies for that GT3037/25G/GT30 upgrade instead.

[AndyF_RSX]

Steve,
I don't like to be accused of not giving out enough information :D:D
IMHO replacing the manifold may well be a good move but it depends on how restrictive the original is. I've heard rumours of people gaining 20bhp+ from switching manifolds but how true it is I don't know..... Only way to check is to get someone who has one to confirm if it was worth it or not.

Andy

[Mosi]

Ok Andy, in that case...

Has anyone upgraded their exhaust manifold on an evo VII ??

Please get in touch ??

[Reims]

Mosi, stop ****ing about and buy a new turbo!

That way you get a new manifold, you wanted to spend 5k didnt you? This is where it should go.

BTW, my friend brought one of RC developments stainless manifold and sent it back, crap was his impression, not a very good fit.

[JUST CUSTARD PLC]

I am surprised TT doesn,t stand for Twin Turbo by now ????

Well?

[RichW]

Total Twit, Total ****** ...... could be any really! :p


Rich ;)