Xu10j4rs Head Porting

[swordfish210 20]

Before you flame me let me explain. A friend of mine has a GTI-6 engined 205 and is on the move from road/show car to track car and he is looking for a bit more power. Now the car allready has some cams fitted (not sure on spec) and has made 200bhp on the rollers (but as with any rollers the accuracy can be debated until the sun dies out)

 

Now he has been offered a head porting job which he was thinking about getting done but i was quick to tell him not to bother. I told him that as i understood it the heads flow pretty damn well anyway and it can be very easy to make the head worse rather than better, or he could spend the money getting it done and have no resulting improvement.

 

So, am i correct, obviously i don't want him to rush in to getting this done and end up loosing money on what could essentially be a chocolate teapot procedure.

[wracing 19]

What supporting mods has the engine already got? My understanding is that the gti6 flows very well as standard and all it really needs is a clean, remove flash marks and blending the intake manifold.

 

 

James

[swordfish210 20]

What supporting mods has the engine already got? My understanding is that the gti6 flows very well as standard and all it really needs is a clean, remove flash marks and blending the intake manifold.

 

 

James

 

Just the cams and the carbs, not sure what make the inlet manifold is though

[Matt Holley 11]

I'm guessing this is Dwaynes 205? If so they are piper 270 cams iirc, fairly mild anyway.

 

Quick edit, inlet manifold is a jenvey/longman with 45 dellortos, it also has a maniflow exhaust manifold

Edited November 16, 2010 by matt holley

[swordfish210 20]

I'm guessing this is Dwaynes 205? If so they are piper 270 cams iirc, fairly mild anyway.

 

Quick edit, inlet manifold is a jenvey/longman with 45 dellortos, it also has a maniflow exhaust manifold

 

Aye that'll be the one.

[welshpug 1,662]

Bang on from what I've read and understood Mark.

 

IMO he'd get more from his money from getting some forged pistons that will accept lumpier cams (or the standard pistons machining...), then going for proper induction setup and management

 

 

OR, get hold of an XU7 head and have that worked over by someone that knows what they're doing

Edited November 16, 2010 by welshpug

[swordfish210 20]

Good stuff, glad i was there to discourage him now. If it were my car i would be spending some money on some mappable ignition, but he has just had a cage and seat mounts done so he might be short on cash...not to mention his upcoming wedding

[wracing 19]

Not wanting to ignite the carbs debate but i would go engine managment if he could stretch. Then up the compression ratio and some longer duration cams

 

James

[saveloy 8]

Done correctly, you'll always gain from head gas flowing.

I could rub it down in an epyleptic fit and still see a 5% gain.

[Miles 331 1 Cars]

It's not the power zapping 4-1 manifold which is a unequal length pipes? If so change it as they are known to reduce power and Torque

But I'd get some better cams with piston or piston work to match, Some bodies first

[Mattsav 1]

Done correctly, you'll always gain from head gas flowing.

I could rub it down in an epyleptic fit and still see a 5% gain.

 

The key being 'Done Correctly'. Ive seen some beautiful heads that flowed up to 30% less than std!!!!