View Full Version : Power manifold

6th July 2000, 21:16
any one know where i can buy a "power manifold"Power engineering have none in stock

6th July 2000, 22:35
Scoobysport can get hayward and scott to make them up... these are a fair bit cheaper than the unit that PE imported.

10th July 2000, 12:53
Double post... whoops.

[This message has been edited by MorayMackenzie (edited 10 July 2000).]

10th July 2000, 21:09
the hayward and Scott headers don't leak.
They do burn your undertray as did Nicki Grists header set by Jung.

Changes the sound from a deep throb to a rasp.

No power gains yet until it is mapped.

Power Engineering just buy off the shelf you should search for more competitive outlets.

11th July 2000, 11:13
Scoobysport can get hayward and scott to make them up... these are a fair bit cheaper than the unit that PE imported.

(Deja Vu? http://bbs.22b.com/ubb/smile.gif )

25th July 2000, 11:45
I've the "power"-manifold now on my Impreza Belgian-specs-with scoobysport backbox and I would tell you this:
*about the noise: the beatifull boxersound is replaced by a "rasp" at low revs, but WRC-sound from 3500 rpm on.
*the engine picks up smoother and continues to develop his power much better than before up to the rev-limiter.
*you can really feel the increase of power, and this autumn I'll organize a rollingroad session "Roll over Belgium" to have the figures. (Was before 236 Hp and 336 Nm)

[This message has been edited by turboke (edited 25 July 2000).]

27th July 2000, 13:19
Here we go..

people causing shite without knowing...*thats my job* http://bbs.22b.com/ubb/wink.gif

Upto now I have seem several header setups.. ranging from stock to ported..to equal length

I have run two.. and worked on others...awaiting feed back. http://bbs.22b.com/ubb/smile.gif

Some are 4-2-1...others are 4-1.. some run different length and sized primaries...

There are differences between tuned length and equal length headers.

Even the 4-2-1 and 4-1 design should be chosen to meet the requirements of your car.. low down.. or top end power...

I am no exhaust expert.... no way near.. but I do know some principles.. http://bbs.22b.com/ubb/smile.gif

Pete.. There are ones that do come in just 2 pieces... FYI. http://bbs.22b.com/ubb/smile.gif

I was suprised by the number of sections yours (H&S) come in.. but they are sleeved slip joints.. so leakage shouldnt be a problem.

What did you think of Mark's headers ?

Was about 6 hours of porting..using an industrial air die grinder...

Beeny...Shut it! .. unless u have something useful to say... lol

J *let the flames begin*

Pete Croney
28th July 2000, 12:59
Hi J

I haven't seen a two piece one, does it have a concertina like the OE one, for pipe expansion or is the OS bank and up pipe in one section?

It is a lot of sections, but it is difficult to a) fit everything in and have the pipe lengths so close to equal, b) when bending such tight radii, a mandrel bender can crush the inner edge so some remedial work is required before assembly.

I thought Mark's headers were good. 6 hours though, you need a bigger compressor mate http://bbs.22b.com/ubb/wink.gif

It was when doing some work on Pat's car that we saw the problem (see old posts on scoobynet) and we have since done this to three customer's cars. Incidentally, if you are thinking of doing these on an exchange basis, the phase II headers are different (better flow from the NS bank). We take less material out of the intermediate joints, as there doesn't seem any point enlarging these to a diameter much greater than the pipe either side.

I was suprised at how much it deepened the exhaust note and all cars (Link fitted) have required some fettling to suit the new engine ability.

28th July 2000, 14:13

My compressor is big enough.. Industrial floor mount job http://bbs.22b.com/ubb/smile.gif

None of this little Clarke hobby shite... lol

I was only going to work on the actual ports.. but decided to work on every joint.. perfection is required.. http://bbs.22b.com/ubb/wink.gif

The joint is between the two banks..to allow for expansion (slip joint)

I removed material from the intermediate pipes to allow a free flow to the gaskets.. yes perhaps only returns 1% extra... but I am crazy like that http://bbs.22b.com/ubb/smile.gif

I realise the headers vary with the history of the subie.

I also put bosses in Marks headers for EGT sensors on each bank and the up-pipe.. yep he loves gauges http://bbs.22b.com/ubb/wink.gif


28th July 2000, 17:57

Cheeky sod........spec as requested, and yes, you did a FANTASTIC job.

As far as sensors, etc' go, well someone had to do it. At least now, we can get some accurate EGT info http://bbs.22b.com/ubb/biggrin.gif.


28th July 2000, 18:10

You are too modest.. but thanks.. http://bbs.22b.com/ubb/smile.gif

You have volunteered to test stuff for me ?

I needed someone to do destruction testing on some bits...well volunteered http://bbs.22b.com/ubb/wink.gif


Remember Silverstone this Sunday.. http://bbs.22b.com/ubb/smile.gif

We'll have to meet up sometime... just need to sort a few more bits out on my car.. lol

yeah...yeah.. i know...never ending!


5th August 2000, 12:32
Does anyone know if the Sti or RA manifold is different from the normal wrx one? And has the design changed to suit the later smaller turbos etc...maybe in pipe diameters?

I'm wondering if I could benefit from upgrading the manifold in this way instead of buying an individual runner style spaghetti manifold. The main reason being cost, but also I don't really want to lose that distinctive out-of-phase boxer sound!

How much benefit have you guys found by cleaning up or enlarging the passages? Is it worth the effort? Does anyone make a replacement steel manifold similar in design to the std one, but just larger and less restrictive to suit the bigger turbos?


8th August 2000, 17:14

The differences between the RA and other models are to be found in the heads. Both the RA and the STi / STi II had EJ20G closed beck blocks :) But the headers are the same... when I ported my headers, I "borrowed" the headers that came off Pete's rally car (which now runs equal length headers) and prepped them ready to swap with my headers. They were the same and have a horrid flow restriction on the OS bank... the Lambda sensor mounting location doesn't do flow any favours at all! This can be ground down to improve flow....

If you don't want to lose the sound, you will like the effect of flowing the standard collectors... the engine note deepens, it even gets a little bit quieter, but the distinctive off-beat throb is still alive and well...

Cleaning up the headers did make a difference... my LambdaLink showed a reduction on voltage (it was running leaner). Because the Link only uses manifold pressure (not mass air flow) this leaning could be explained by an improvement in volumetric efficiency (better cylinder filling / scavenging). It's not difficult to do, doesn't take very long and needn't cost very much.

As for a steel replacement, I have seen a set of steel collectors which replace the OE ones, they fit the normal cross-pipe and up-pipe. IIRC, they are made in the US and in Oz... can't remember a URL, but people like MRT, BPM and PBM would be a good starting point... these Aussies and Kiwis love to meddle with cars and come up with some really trick stuff! :)

Hope this helps,