I've recently bought an up-pipe for my yr2000 uk turbo, so while i was doing that I thought i'd have the headers off and port them, now, I have seen other people pictures and they have taken quite a lot of metal out of the headers to get the flow right, having removed mine, I thought i'd make a template of the cylinder head outlet, rather than assume that the gasket was the right size, only to find, that the head and headers already virtually match!!! I'm checking all of the joints, but so far the only one that really needed any work was the o/s header to up-pipe joint, and thats down to the up-pipe being a 2 inch bore.
SO in summary, are people checking the actual port sizes, or just assuming that the gaskets the size of the port in the head, I can't see that i'm gonna gain sod-all at the moment, expect smelling like a machine shop!!
Oh, and losing the rattly heat shields!!

Your thoughts please......



Ron.

 

A lot of headers are MUCH smaller than the port size on the cylinder heads. therefore it makes sense to take the step off and improve flow. Lf you have a set that almost match, good luck to you. Maybe they've been done already?

We do it for a number of people whilst rebuilding their engine and all comment upon how much faster the turbo spools and how much free-er revving the engine is.

It is a worthwhile mod and not expensive for the gain [ in most cases]

David APi engines / APi Impreza

PS if you have removed the heat shield be sure to replace them with something - usually heat wrap, to prevent heat escaping when it can be used to improve exhaust gas temp and improve turbo response

 

The problem is that the ports in the head and the ports on the manifold may be the same size but you can't be sure that they will match up when fitting. The other benefit is that you will create a reversion lip that will impede the gas in the reverse flow direction. There are other lips that can be removed in the center and uppipe as you've discovered.

I'm not sure I've ever seen a comparison between unported pipes and ported on a RR without any other changes, so it's difficult to prove a gain.

F

 

David, yes, I've got plenty of wrap, rest assured!!
There's no way they've been done before, I've had the car from new!!

With regard to them matching up, I made a paper template of the head, complete with studs locations, and then transfered that onto the header, so they will line up, there'd be no point otherwise!!

Thanks....

I guess i'll just have to carry on now, and see what i end up with!!

 

With luck, turbo spool up - up to 300 rpm sooner, or more in cases where the ports are very mismatched.

Good luck. David

 

David so you wrap the standard headers then no cracking then

 

There are signifigant gains to come from porting the O/E headers and up-pipe IF DONE PROPERLY. It is all about increasing gas flow/velocity. My first Subaru headers were ported at Scoobysport and there was no difference. When I took the headers off the reason was obvious.
Ask Rich Wild at Jap Innovations or others that I have done it for as to the gains in spool and crispness it gives.
I have never had any problems with wrapped O/E headers and think this is another myth to enter Scoobynet. To run into problems it would be necessary to run the EGTs well beyond the normal for road driving.

 

Mine were also ported at Scoobysport ... some difference in exhaust note, but no marked difference in performance, what should I check for, and how should this be done properly in the future ?

Thanks

 

On my headers from Scoobysport the exhaust ports to the runners were chamfered for about 1/4". Sort of thing you could do with a file or a power tool in minutes.

Porting the headers properly involves the removal of quite a lot of metal in the ports, splitting the cross pipe and working on these joins and work to the uppipe all designed to improve gas flow and velocity.

 

Harvey

I have seen a lot of posts where you have ported peoples headers....

If i were to have my headers ported as part of a engine tuning project who would be the best person/place to have the oem headers done properly.. ??

Do you do it for a price .. or would you recommend another person/place ??

I am thinking of bigger TMIC, Turbo, Re-map, hoses fuel pump.. etc.. i am looking at approx 330bhp/300lbs on a UK my2000 but don't want to lose the scooby flat4 sound i have with my decat..

APiDavid..

I see you also port the OEM headers on your post.. i am assuming you would do the whole job to a certain spec/price

Do you think i am being a bit over ambitious with my power figures for a UK engine ??

Thanks

Simon

 

TEdED - looking through some dyno figures the other day, I did see one guy get 382 bhp & 322 ibs of ft torque on standard internals with bigger turbo; injectors, front mount & some porting etc....

 

I have a set of Harvey Smith ported OEM headers.
amazing difference, along with a few other bits and bobs it took me from 258 to 330 bhp.
td05 makes 1bar from 2850rpm and full 1,3bar at 3150.

which is nice, value for money its one of the best things you can do to a UK car.
When you ask Harvey to do it (or API) ask him about his lightened flywheels.
save yourself on postage getting both together.

Andy

 

peanuts,
Is your TD05 an Andyf job or standard?

 

Brian Longs Impreza book, makes a note that the MY03 WRX facelift Impreza has a revised "exhaust manifold aimed at smoothing the flow of exhaust gases".

Has anyone pulled apart a blobeye (JDM presumably) exhaust headers spotted these supposed imprvements?
Are they also found on the UK cars as well?

If so, is it worth starting with blobeye headers for porting than classic ones?

Nick

 

Palatine,
std. td05, front entry conversion and rotated the housing slightly to negate the need for grinding the gearbox lug.

will be 18g converted very soon though

Andy

 

Nick, this question has been asked before but the answer was no real difference. If you do get hold of a set then let us know if you think it's better/worth looking at?

F

 

Not that hard to do, and the biggest cost was the gaskets.

I got a Die Grinding tool off ebay for £5.00 and hired a die grinder for the morning for £10-ish..

The most metal came off when I was matching the manifold/head gasket to within 1.5mm of the fire ring. You then flow that down and smooth it in with a softer stone in a drill.

I did a similar thing along the 'flow' of the manifold making sure that I did not increase the bore unnessarily and slow down the flow. Basically the rule is to remove obstructions and smooth, rather than open it all up.

I had OBX equal length headers and up-pipe before but changed back cos I missed the Burble.

 

I bought a set to do, so the scoob is not off the road for to long