Anyone seen or bought a alloy tubing (larger) inlet manifold for their WRX?
If so, how much did it cost and did it have any of the brackets etc to fit other parts and pipes to it like the oe manifold?

 

Can't help you very much I'm afraid but a Canadian company called Magnus Motorsport is manufacturing an alloy manifold which they claim gives 35HP. You can see a picture here

http://www.magnusmotorsports.com/STI_info.htm

It has been discussed a little on NASIOC so a quick search on there may provide a little more info. Price is circa US $980 / CA $1200.

 

theres cheaper ways of getting more power, the oem inlet manifolds are more than capable.

David

 

How's mine doing David, i'll have to sort that out in the next week or so if we can.
Cheers
Minty.

 

OEM from 97 onwards are way out of balance, recently chopped a few up out of interest
Just make one is the best way

Andy

 

How do you mean?
Would you care to expand on that Andy for us technical beginners?

 

The ports are different sizes throughout each leg and some of the bends are very tight radius which will cause turbulence and reduce flow.

Andy

 

what manifold choices are out there (and proven) for >97 models?

Would they contribute massively to the power/breathing ability?

Brad

 

Andy.. I can guess what your up to

Any pics, as I was just about to set about a 97/98 but most likely in a different way to you!

 

Thats interesting, didn't think they'd be out of balance, more the internal surface isn't smooth (being a cast)....

Cost of alloy tube above is crazy though. Wonder if its possible to get them balanced and gas flowed in some way...?

 

It is possible...

you extrude hone them, Richard (Dowser) on 22b did his this way... extrude hone in the uk arent interested.

David

 

Why does it need to be alloy tubing?

 

I have a <97 manifold modified and fitted to a >99 set of heads. It is a job a I can probably do, but it would cost about £300 including the adaptor plates (different stud layout on later heads).

Paul

 

Has anybody done a dyno tests with a phase 1 manifold compared to the phase 1.5 and 2?

 

I'm thinking alloy tubing as its what is used on the prodrive rally car...and it allows much bigger diameter piping...equals more power and equal length tubes.

 

Is phase 1, 1.5, etc just the age of the car and not modified inlet manifolds?

 

phase 1 = upto and including ver2
phase 1.5 = ver3 and 4
phase 2 = ver5 and 6

 

No they don't. They use a cast magnesium manifold based on the early pre97 part. The stock runners are more than large enough, and you will not get any more power by enlarging them.

Paul

 

Just the man...Paul, are you available sometime in the future to do some head work on 02 WRX to suit 2.5L? Also, do you polish inlet manifolds and ports?

My email is anthonyplumley@its.hoarelea.com

Oh, I've seen a prodrive rally car with what looks like alloy piping on the inlet manifold...oh well.

 

Prodrive used a fabricated inlet manifold for the 2000 car only I beleive. THey have since reverted back to a cast unit.

Paul

 

Two almost identical spec cars.... Only major differences were HKS headers/H+S headers and one has phase 1.5 manifold and one has phase 1.

One car made 630ftlb the other made 560ftlb, boost for boost.

Rob

 

630ftlbs....does the owner not like rubber on wheels?

 

Rob, thats interesting... A&C?

Because there were other differences if so.

David

 

However the stock runners are all different internal areas through out the run and the plenum is far too small for optimum power. On the 99 manifold one runner reduces to 70% of the CSA of the others and some of the bends inside radius' need to be seen to be believed

Andy

 

I was thinking more of a pre 97 manifold.

 

Yes the early phase 1 manifold is better all round............ but can be improved on

Andy

 

David, i was thinking about differences that would effect torque....

Injector set up different, same Cams.

R.

 

Coatings - Temperature differences.