Are there any advantages to fitting them, in terms of performance?

 

I believe they are very dependant on other modifications, from what i have heard.

 

I assumed you would have to do them in conjunction with other mods. I think I'm a heretic, as I actually prefer the sound of them

Main reason for asking was that I believe that the WRC cars and others of their ilk run them, yet people modding "for the street" don't, which made me curious.

 

Quite a few people are running them, ie a lot of the big power boys IYKWIM. I am considering them, but cost just makes me cringe, and i dont want to loose to much of the sound TBH.

Steven

 

There are good gains to be had once you've mapped around them. But depending on the other mods they'll likely raise the spool point of the turbo a bit (my Maxim's raise it 200rpm), but flow much better elsewhere.

Richard

 

Equal length headers only give small % amounts of HP gain, so the more HP you are pumping you play % games. So for most people the cost vs power is not justifiable

 

Can anyone demonstrate a greater area under the curve that is any different to just using a larger turbo? If so I'll have those headers

Having mapped various combos of TD04, TD04 hybrid, MD304, VF29 and HKS, Maxim and Scoobysport headers and studying published performance plots/data for some other combinations including the popular Ion ones I've not tried a second set of headers yet.

Willing to be convinced that they do anything other than effectively resize the turbo a bit (plus save weight, look and sound nice).... Rigolis don't have any trouble with the standard headers ported it seems.

Other issues with headers are blowing apart at slip joints, lagging, melting things that are too close, stopping the ECU knock correcting (not new age it seems), some better than others.

 

I have a custom 4-2-1 equal length manifold, spool up is on average 2-300rpm higher than the stock manifold , but at 5000rpm and 1bar we had to add circa 10% more fuel to hit the same AFR.

This is with a P20 exhaust housing, I also have gas flowed heads which will effect the VE in a non-linear fashion

 

John

Speak to Harvey re the difference they made on his car. He had excellent power from a VF28 using them.
I think the rest of the engine needs to be able to breath well before headers make much +ve difference.

I'll find out shortly at WL5

 

Installed EQ headers and air induction on my 95 wrx.
Heat of headers even with coating on it is real high thus all the enging bay is warm like stove heating incoming air as well. The lag is more the HP is less. Going to put STD back.

 

alex- did you port your stock headers???

i have done this with mine and it made a noticeable difference in spool up time.

worth doing before refitting i think.

 

I've used two different tubular headers, was happy with both sets.

 

With the ones I have on now (not equal length, though - think these have been on your car too, Moray? ) I'm finding the the turbo (MD254) actually begins to spool from 2100rpm if in 5th... only 0.3bar or so, but it's going round!
Which I think is rather lower than the standard one would manage?

 

got a set of headers on mine and the car pulls much better from 4600rpm and sounds nothing like an impreza

 

jonny, yes ive ported them. guess it'll work as STD headers fitting looks poor.

 

I have Ion Performance tubular headers but they are not equal length. With ported cast headers on a VF28 I had modded slightly along with my other mods I got 355bhp. A few days later with the addition of the 4-1 headers only I got 377bhp on the same rollers.
1 bar in 4th moved from 3,400 to 3,700rpm but the car was much stronger thereafter.
Changing to an Ion Performance turbo immediately gave 417bhp and the car has now been developed to give in excess of 450bhp and still on 2.0 litre.
I have a set of Ion Performance headers for sale if anybody is interested.

 

I have a set of SYMS racing headers (not sure if equal) had them properly lagged and am very happy with results, ie: 270 RWHP with std VF23 on stock STi-3, Link, Bosch pump & coils.

 

Harvey, how much?

 

Hi Steve:Just picked this up so will check what it cost and get back. It is ceramic coated already.

 

Harvey What Fuel and boost are you running for the 450hp if its not a trade secret?
[Edited by sphazell - 5/12/2003 10:20:23 AM]

[Edited by sphazell - 5/12/2003 10:27:22 AM]

 

Sphazell,


Changing to an Ion Performance turbo immediately gave 417bhp and the car has now been developed to give in excess of 450bhp and still on 2.0 litre.
I have a set of Ion Performance headers for sale if anybody is interested. .

VF-28 was 377hp

Skassa

 

Sphazell:Fuel is Shell Optimax plus 1ml/litre NF but if I am going to run on rollers or track/WOT for any period then I up it to 2ml/litre for added safety. Boost is 1.8 bar and with the present map there is no knock so I think a little more advance is possible.

 

I have the Power Engineering equal length headers fitted at the same time as Blitz induction (replacing ITG panel), they only gave about 4 bhp increase on a car which at the time was producing 290BHP. But they gave 19ftlbs of torque, 11 bhp at 2500 and 9bhp at 4500. The engine was more responsive and sewing machine smooth, they blew apart at the joints but that was because the bars which go across the joints hadn't been fitted I got a lot more power once extra mods were added but don't know how much to attribute to the headers?

Vince

 

Why do you ask Jon?

Matt

P.S. Has anybody actually got Equal Length headers or do most people actually have un-equal length?

 

I have equal length Maxim/PE headers. I like - would even go as far as to suggest that they're the perfect match for an ej20 with td05 sized turbo. Slightly later spool with strong mid-range and top end.

I tried an iON set too - they produced more power, but less area under the curve, if you will (power band moved about 300rpm up). I reckon I was quicker around a track with the Maxim, but (much) faster dragging on the autobahn with the iON.

My ej25 will be mapped with the iON though - it's larger diameter pipework is, IMHO, better suited to a larger capacity. We'll see

Richard

PS: I also tried the Tezet/Supersprint design - for track only work this was very good if used with their up-pipe too. Spool point too high for road use IMO though.

PPS: you *really* need to map around the header to get the best from it.