Resolved 2G exhaust manifold crack

[Generation X]

OK... here's the deal guys. Lately I have been having some real bad spool up problems with my FP Green, and when I say bad I mean like 20 psi comes at a miserable 5000 to 5200 rpm. I have done boost leak tests, compression tests, and I have even seafoamed the car but I still can't seem to get 20 psi by atleast 4000 rpm.

Anyways.... I ordered a new 4 layer exhaust manifold gasket, along with a new 7cm stainless steel gasket. But, as I was removing my exhaust manifold and inspecting it I found a crack down through the side of the divider and I'm wondering if I should even take a chance on re-installing it, but I don't want to take a chance of it cracking more and a piece of it destroying my FP green.

Here is a picture of what I'm talking about, and feel free to give me any advice. I'm planning on buying a Evo III exhaust manifold if needed. Thanks for any advice.

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[CanadianTSi]

Pretty much every 2G manifold has cracks right in that area. Its very common and I wouldn't worry about it.

 

[romeen]

Cracks in the divider are fairly common and I don't think it has any significant effect on performance and I highly doubt that is the cause of your issues. Personally I would not replace it just because of that. I am not aware of anyone having had a piece of the divider break off and damage the turbine fins.

However if you do decide to replace it with an EVO3 manifold I believe that Mitsu used a higher nickel content in those manifolds making it much less prone to cracking as well as having a larger diameter collecter which might match the turbine inlet of your turbo better (I don't know how big the inlet of the FP Green is).

 

[Generation X]

Well... actually there is a crack on the other side as well that my camera didn't pick up, and one of the cracks looks like it's about to come out through the top of the manifold, but to be on the safe side I ordered one from Slowboy for $139. Knowing the bad luck I've been having lately, a piece would break off and destroy my $1300 turbo. Thanks for the replies and advice!!

 

[jongreene]

Did you ever look at the FP race manifold?

 

[staticbrainwash]

Or the evo GT manifold. People have had good luck with that too.

But damn is that FP one pretty.

 

[Generation X]

Yeah I love the FP race manifold. It's awesome looking, but for $425 I'm going to have to see alot more reviews on it first before I go spending that kind of cash.

 

[staticbrainwash]

It's FP and it's cast tubular. I'm sold right there, haha. Now if i just had the cash.

 

[bling5tatus]

fp manifold is listed as 325 on their site.... not 425.

 

[kenamond]

Crack looks very familiar.

Before porting:

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After:

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I wouldn't worry about it. But that FP mani sure looks nice!

 

[Generation X]

fp manifold is listed as 325 on their site.... not 425.

Your correct but if you want it ceramic coated it's an extra $100 bucks, and if I were getting one I would definitely have it coated.

 

[Generation X]

Crack looks very familiar.

Before porting:

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After:

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I wouldn't worry about it. But that FP mani sure looks nice!

Yeah looks very damn similar, but the thing is, is that mine cracks all the way down to the bottom, and I can almost feel on the outside where it may eventually crack all the way through. I just went with the Evo III manifold for now.

 

[gsxtacy]

EVO III is my advice too.

You can have it welded but it will do it again.

My EVO III manifold is holding up nicely to my 6152e...

 

[Generation X]

EVO III is my advice too.

You can have it welded but it will do it again.

My EVO III manifold is holding up nicely to my 6152e...

Just curious bro.. are the runners on the Evo III manifold any larger than the 2g manifold, or are they the same size? I know the collector is bigger on the Evo III but I wasn't sure if the runners were bigger also. Thanks!!

 

[Defiant]

It's not just DSM. Virtually all cast manifolds will both crack and eventually start shedding chunks with age. Turbos add to the thermal load.

 

[dsm-onster]

Just curious bro.. are the runners on the Evo III manifold any larger than the 2g manifold, or are they the same size? I know the collector is bigger on the Evo III but I wasn't sure if the runners were bigger also. Thanks!!

yes they are larger. I've never seen the inside of a ported 2g exhuast manifold, but considering the differences between the evo3 and an unported 2g, it looks to be what I'd expect to see for a ported 2g manifold. But, being the evo3 has much more "meat" than a ported 2g, it should serve a longer life.

 

[romeen]

Just curious bro.. are the runners on the Evo III manifold any larger than the 2g manifold, or are they the same size? I know the collector is bigger on the Evo III but I wasn't sure if the runners were bigger also. Thanks!!

I believe the runners are the same size. Before I installed my EVO III manifold I compared it side by side with the stock 2G manifold that I had just removed. Although I didn't physically measure the runners, a side by side visual exam suggested the runners were the same. This quote is from RRE's website:

EVO III Exhaust Manifold:
These have the same runner diameter as the 2G exhaust manifolds but they have the larger collector that matches the larger inlet to a 16G with a 7cm exhaust housing.

It's about halfway down the page here:

http://roadraceengineering.com/eclturbos.htm

 

[dsm-onster]

I remember my dividers looking 'pointier' than in the pic on the RRE site. . . I really need to pull of my exhaust manifold. I think it has been ported.

 

[Generation X]

I recieved my Evo III manifold from Slowboy, damn there fast!! I highly recommend doing business with Slowboy!!

Anyways... from what I can tell by the naked eye is that the runners do indeed look about the same size as the 2g. I mean it would probably take some type of special micrometer to see any difference if there is any.

Although I didn't have mine ported, I think it should still flow just as good as a ported 2g manifold, but atleast my turbo is ported though. Maybe some time on down the road I can remove it again, and grind the step away.