Wondering if anybody out there has any experience with, or dyno data on different aftermarket headers. Any notable advantages / disadvantages between 4-1 systems (e.g. HKS) versus 4-2-1 (e.g. Power Engineering)?

 

4-2-1 more spread of torque, 4-1 better up top (this is in general).
Headers should be mapped to some extent with the turbo.
The PE one seems to work very well with the TD04.
The Hayward & Scott one - from what I've heard - is a bit of a weirdy to map to for some reason!
The HKS is a good all-rounder. Haven't heard any 'bad press' on it from anywhere!
iON Performance seem to do one 'of interest', but I think it's pretty new over here so not a lot of feedback yet...

 

Just thought - - any particular reason you're only looking at 'equal length'? They are tuned to a very narrow rpm band - good on track, not so good on the road... or is that what you're after? I'd keep it open to any tubular design if I were you

 

The HKS and Ion headers are not equal length and consequently provide for a generously wide band of improvement. HKS need an up pipe to go with them in addition.

 

Bob,not meaning to misquote you but I thought you were'nt particularly keen on after market headers and thought you get near enough results from just porting the oem? If I have got that wrong,what sort of gains would you estimate from the HKS? Happy New Year,Deep.

 

Depends on the headers, I've tried a few and mapped cars with a variety of different ones, its very much a matter of what you want to achieve, un-equal length seem to give the best overall gains but the Maxims a la PE do work very well on UK cars with a TD04 turbo kept in place, on STi's they are dissapointing. There are some equal length ones that don't seem to give any gains at all so be wary.
I have un equal length headers on my car at the moment and they are at least as good for spool as the ported std ones I had but I also have a good replacement up pipe and some turbo mods which contribute.

 

I've heard recently that the Maxim's work very well with a front entry TD05 on a Euro spec car. Seems to be some VF series that don't quite 'gel' with them ?

 

Its more to do with cam profile and timing than anything, STi's and equal length dont gel ... I don't really think it matters what the turbo is within reason.

 

Andy, the Maxim worked well with my vf23 too....the 05 can just do more for it

Richard

 

I plan on keeping the stock TD04 in place for some time. Given this, and the intended use (largely street applications and the occational track day up north) would you suggest the HKS or PE header (seeing how both are getting decent reviews)? Another concern, possibly minor, is whether or not I need to reroute (i.e. splice wires, cut away heat sheilds, etc.) the EGT sensor for the different location of the EGT bung on the PE headers. For the HKS, a scoobysport uppipe seems to solve this problem.


Ben

 

The PE headers don't have an EGT bung, so your decision maybe made already?

Richard

 

The HKS has an EGT 'hole' at the collector.
Haven't tried a PE one - got an HKS - but if you're not planning on changing the turbo (& don't find the car sounding like a big bike a turn-off), the PE one may be a better choice - the HKS is largely set up for higher rpm - not exactly what the TD04 is good at! I understand that the PE one should be better mid range. But, as I haven't driven one, this is purely from listening to others' points of view & looking at graphs!