Reverse Intake Manifold thread

[War_Panda04]

so im debating on doing a reverse mounted intake manifold for the STi. wanted to get some opinions on brands, designs, etc. id love to be able to still keep A/C in the car but if i decide to go this route it doesnt look like thats possible.
[MENTION=1]IGOTASTi[/MENTION] [MENTION=1172]Alin[/MENTION] [MENTION=9]HolyCrapItsFast[/MENTION] [MENTION=652]Grinder34[/MENTION] [MENTION=662]Batmobile_Engage[/MENTION] [MENTION=5942]Real Auto Dynamics[/MENTION]

 

[Alin]

Are you referring to the "going rotated" path? I've only seen pics, but never actually read up on it.

 

[War_Panda04]

yea rotated, reversed, same thing i guess. i wouldnt be using the factory manifold and just turning it around i would actually buy a new manifold i want to have it painted to throw some color into the bay you know

 

[Alin]

Someone is selling an extremely rare $4,000 one on Nasioc if that tickles your fancy! :rofl:

 

[War_Panda04]

YEA NO THANKS... rather not spend the same amount of money on my short block and intake manifold... im looking for $1500-$1700 range maybe a little more if its worth it you know

 

[Alin]

I'll look around if anyone is selling their kit from a partout and link it here if I come across one. :tup:

 

[War_Panda04]

thank you sir. im not opposed to buying new either. its going to be shipped to Japan for Yokoi-San at MCR Factory to paint it for me. if i find one in Japan that would be best so i dont have to pay shipping twice you know.

 

[Alin]

Yahoo auctions is another option then! :tup:

 

[War_Panda04]

never used that before. im going to have my buddy in Japan take a look for me. but ill check out yahoo auctions as well

 

[War_Panda04]

im looking online and all i really see are 2 brands. process west and Cosworth. does anyone know of any others?

 

[Doppelganger]

im looking online and all i really see are 2 brands. process west and Cosworth. does anyone know of any others?

Both are top notch process is a beast.

(Edited this part some people said cosworth hurt their power but I have only heared good things about process west just fyi)

The NA manifold I'm converting out flows cosworth but you won't be able to keep ac with it reversed. The cosworth amd stock manifold I believe you can keep ac with but requires 19mm phenolic spacers. I'd go ks tech phenolic spacers since they are better designed compared to the other companies.

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[Doppelganger]

If your not keeping ac then go with the 2.5i na manifold. Out front motor sports sales converted ones or you can pick a na manifold up off the net for around a $100 and out front does the extra removal of tabs. You would need the 19mm phenolic spacers and a set of out front motor sports fuel rails or you can buy moore performance fuel rail spacers so you can use your existing aftermarket or stock fuel rails.

If your tgvs are ported you can use a legacy na manifold (large plenum short runner) as well. And have out front convert it for you so it can bolt up to the tgvs so you don't have to worry about the fuel rails or phenolic spacers I believe.

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[War_Panda04]

i havent decided yet if im going to keep a/c.. leaning more towards no since i usually just drive with the windows down anyway plus i have another car if its really that hot i dont have to drive the STi.

the NA manifold isnt a bad idea but arent those still facing backwards? is it literally as simple and spinning it around?

 

[Grinder34]

First question I usually ask is: why? Why do you want to reverse the intake manifold? IIRC, it's usually to have a shorter IC piping for turbo lag with an FMIC. Is that why?

There are other ways to achieve low lag with good cooling (see Holys AWIC, for example). But I gotta know the result you're looking for before I can make suggestions!

 

[War_Panda04]

First question I usually ask is: why? Why do you want to reverse the intake manifold? IIRC, it's usually to have a shorter IC piping for turbo lag with an FMIC. Is that why?

There are other ways to achieve low lag with good cooling (see Holys AWIC, for example). But I gotta know the result you're looking for before I can make suggestions!

yes low turbo lag is probably the main reason. cleaning up the engine bay is also a reason plus im getting an awesome chance to have Masashi Yokoi from MCR Factory in Japan paint it for me rather than my valve covers that you will barely see

 

[Doppelganger]

i havent decided yet if im going to keep a/c.. leaning more towards no since i usually just drive with the windows down anyway plus i have another car if its really that hot i dont have to drive the STi.

the NA manifold isnt a bad idea but arent those still facing backwards? is it literally as simple and spinning it around?

The NA manifold pretty much requires phenolic spacers, new fuel rails or fuel rail spacers, relocating coolant header tank to fire wall or making a new bracket for it, new cold side FMIC tubing, the pcv and vacuum lines will be altered a bit as well but yes its just flip the manifold around and your good to go after all that lol. The short runner na manifold is less of a headache.

Personally if it was me looking for an intake manifold and money wasn't the issue I'd go process west manifold.

Second choice would be the NA manifold since the research I've done shows it seems to perform better then the cosworth. I will say the na manifold is very well engineered and you figure subaru spent a ton of hours on R&D making it hence why I went with it.

The issue your going to encounter is if you research on the forums is that the lack of daily driver sized turbos using them (let's say gt35 and smaller turbos for a size comparison) makes it where the forum warriors don't have dyno graphs and data to back their opinions uo with. So most of the info you will get is people that have no actual data to back up their claims saying that the big intake manifold is going to kill your power band or is unnecessary. These are most likely the same people saying porting heads is a huge waste of money since the heads and intake manifold are technically not the bottle neck on the subaru motor.

I'm personally hoping that the mild headwork and larger intake manifold wont hurt my power band but Im aware I might not gain much in return since I'm only running a FP green HTZ turbo.

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[Alin]

Does this help you at all?

PA: Full Race EFR6758 Rotated Kit & Header
http://forums.nasioc.com/forums/showthread.php?t=2820617

 

[War_Panda04]

i could use the headers but im not sure what brand they are. the turbo is smaller than i want and im going to need a custom down pipe for the way i want to set the turbo up in the engine bay

 

[SudoSTI]

Not sure if you've already moved on from the idea but I flipped my manifold so I have a bit of experience. If you're looking to upgrade the manifold, like was said earlier there is Cosworth, Process West, N/A manifold, or the soon to be released Moore Performance manifold. Cosworth is a great and proven unit and with phenolic spacers can retain the AC. PW is better still but makes two versions, one for normal orientation, one for reverse. The reverse version REQUIRES AC delete. N/A manifold I have only seen a couple people reverse but to do so they had cut the plenum a decent amount and weld on a sheet metal portion because the plenum is so large it WILL hit the hood. The Moore Performance unit looks to be the best but is still in beta testing. Already proven to make more power than the PW, has AWIC integrated into it, and doesn't require TGV housings. It also allows for normal OR reverse orientation. Or there's the Tomei manifold that has a throttle body for each cylinder port, but that requires AC delete, is only meant for throttle cable driven cars, and costs $3500-4000. If you have any other specific questions about the setup let me know.


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[War_Panda04]

Not sure if you've already moved on from the idea but I flipped my manifold so I have a bit of experience. If you're looking to upgrade the manifold, like was said earlier there is Cosworth, Process West, N/A manifold, or the soon to be released Moore Performance manifold. Cosworth is a great and proven unit and with phenolic spacers can retain the AC. PW is better still but makes two versions, one for normal orientation, one for reverse. The reverse version REQUIRES AC delete. N/A manifold I have only seen a couple people reverse but to do so they had cut the plenum a decent amount and weld on a sheet metal portion because the plenum is so large it WILL hit the hood. The Moore Performance unit looks to be the best but is still in beta testing. Already proven to make more power than the PW, has AWIC integrated into it, and doesn't require TGV housings. It also allows for normal OR reverse orientation. Or there's the Tomei manifold that has a throttle body for each cylinder port, but that requires AC delete, is only meant for throttle cable driven cars, and costs $3500-4000. If you have any other specific questions about the setup let me know.


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that is exactly the info i was looking for thanks man. nothing was bought yet but i think im going to go with the Process West unless i decide i dont want to delete A/C. if so ill just go with the Cosworth. as of right now the A/C will be coming out. the car wont be daily driven anymore