EvoIII 16G @ 17-19 psi...2.25", 2.50", or 3.0" exhaust?

Shpyder · #1 08-31-2004, 12:08 AM

I have a 1997 4G63 turbo . I want an EvoIII 16G for sure

. Supporting mods will include: upgraded fuel delivery and management, and MBC @ 17-19 psi, ported Evo II 02 housing, and 1G intake manifold and 1G TB.

My question: What size exhaust? 2.25", 2.5" or 3", in terms or value for the buck, for this setup? I plan to get my muffler shop to custom make one, no name brands, WITH cat (no test pipe). I race only ocassionally, and dont drive hard during regular commute, if that helps.

(Mods: have searched, found threads close to this, but not what I was looking for)

97dsmeclipse · #2 08-31-2004, 12:32 AM

Quote:

Originally Posted by Shpyder

I have a 1997 4G63 turbo . I want an EvoIII 16G for sure

. Supporting mods will include: upgraded fuel delivery and management, and MBC @ 17-19 psi, ported Evo II 02 housing, and 1G intake manifold and 1G TB.

My question: What size exhaust? 2.25", 2.5" or 3", in terms or value for the buck, for this setup? I plan to get my muffler shop to custom make one, no name brands, WITH cat (no test pipe). I race only ocassionally, and dont drive hard during regular commute, if that helps.

(Mods: have searched, found threads close to this, but not what I was looking for)

well a 2.5 would be ok, but if you plan on modding it more i would go for the 3", i would be better for the long run, but then you have to get a 3" cat or a 3" high flow cat of ebay for under $100.

soyee7 · #3 08-31-2004, 12:33 AM

go 3in, better exhaust flow = better turbo performance

JoeWagon · #4 08-31-2004, 01:53 AM

2.5 may do fine, but it's not worth saving the money from a 3.0 inch. If the shop uses press bends, like most do, you will want the 3 inch to make up for the fact that it narrows inside greatly.

Also, I wouldn't be so sure about your boost in the future. You'll tune for no knock, and that will determine the boost. You may be able to run 20+psi without knock, in which case there is no reason not to!

Shpyder · #5 08-31-2004, 03:10 AM

3" it is then I guess, especially since pricing doesn't vary too much between the three. And I guess there's no real noticable performance difference between an unbranded 3" muffler shop exhaust and a GReddy or Apexi 3", right?

JoeWagon · #6 08-31-2004, 03:22 AM

Only if the muffler shop uses mandrel bends, like the brand name. If not, it's value drops considerably. I would rather have a 2.5 mandrel over a 3.0 press bent, but 3.0 press isn't all that bad as a cheap upgrade from stock.

Shpyder · #7 08-31-2004, 03:43 AM

Okay, I'll remember that for sure.

One more thing. I'll be getting a 3" then, but what size o2 housing will fit? I was looking at the evo one, and the ported one from SBR, but couldn't find a 3" one...if it indeed exists. Or do they not make 3" ones and just have custom flanges and gaskets that connect the 2.5" housing to the 3" DP.... ?

joemathews · #8 08-31-2004, 01:10 PM

People have run 11s on 2.5 in. pressbent...but I agree that 3 in. is probably your best bet if you are having the piping press bent by a muffler shop.

EclipseRST · #9 08-31-2004, 06:42 PM

i hope your not planning on puting that 1st gen intake manifold on your 2nd gen head are you? the ports on the head are so substantually small compared to the 1st gen ports so you will have a major lip... heres a picture, 2g head, 1g gasket... the gasket opening is the size of the port on a 1st gen head so thats the lip that your goin to have if you put that intake manifold on your 2nd gen head! just a thought...

Shpyder · #10 08-31-2004, 06:57 PM

??

The 1G TB is 60mm right, and thats bigger than the 2G. The manifold...was it the exhaust manifold that came bigger on 1Gs or the intake manifolds? (1G heads are bigger too though right?). Holy crap I'm mad confused all of a sudden, haha.

JoeWagon · #11 08-31-2004, 07:19 PM

He didn't mention TB, did he? He was talking about the intake manifold ports on the head. You aren't going to benefit from a large 1g intake manifold on a 2g head without porting.

2g exhaust manifold is better. 1g head/intake manifold are better. TB size.. I don't know.

hellah fresh · #12 08-31-2004, 11:52 PM

hmm... what about on my 96 RS... what should i port?

o yeah... anyone knows if the BOMZ coilover spings on ebay is any good?

kjewer1 · #13 09-01-2004, 12:59 AM

1g TB is 60mm, 2g is 52mm. I'll second that its not worth going to the 1g intake mani unless you port it or do the full 1g head swap with it. You can get a sheetmetal intake for the 2g head, that might make more sense depending on the situtation (magnus).

Tehre are no off the shelf 3" o2 housings. All of the 3" downpipes start at 2.5". You can get custom tubular 3" housings (I have one) if you need it, but all but the very largest of turbine wheels is smaller than 2.5" major diameter anyway, so it doesntmake sense (mine is ~2.6 so I had to go to 3", for example)

soyee7 · #14 09-01-2004, 01:29 AM

remember also that the WG in the evo3 has a stiff WG spring and will most likely boost creep to around 19psi, especially with a 3in ehaust setup. you should get the WG flapper mod done to the the turbo before purchasing it.

Shpyder · #15 09-01-2004, 01:54 AM

okay. SBR and RRE do the flapper mod thing. Got it.

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