Headwork - How much porting?

[Baal]

I think ill add some 12.6 pistons and have some head work done.

There is this gray/black Clio (who is cheating in N3 btw) but its acceleration is insane, the difference between mine and his is huge and he absolutely destroys me in uphill stages, i know that he doesnt have anything besides headwork (and maybe race gas) since he has no access to parts like cams etc, last rally he blew the engine so im guessing he did some stupi ammounts of head milling to incrase compression but he probably has some huge ports.


Anyway, back to the question how much should i be porting and polishing the 172 head?, i dont want to absolutely kill all my torque by overdoing it, so any input about it is appreciated.

 

[stan*]

If you have to ask on a forum, leave it well alone...

 

[Baal]

very useful...

i am not going to make one of those getto dremel portings -_-, i will take the head to my friends machining shop.

So please if you wont answer my question dont bother replying ok?

 

[Baal]

for the record i got another engine ported in the past, but every engine has different tolerances and a very slight overporting can kill all the low-end torque and i dont want this especially in a rally car.

 

[stan*]

Dont take offence mate, im trying to save you wrecking your head/cars performance. The terminology you are using implies you have no experience with flow/performance---again, dont take offence to that, not many people do.

My point is, I really wouldnt attack it unless you have experience in what you are doing, OR have many years spare to learn what to do.

 

[hmh]

Stan definitely has a point, but then comes a question - how much good porting work should cost if done by an experienced engineer? Clio 172 head is in question of course.

 

[Baal]

Dont take offence mate, im trying to save you wrecking your head/cars performance. The terminology you are using implies you have no experience with flow/performance---again, dont take offence to that, not many people do.

My point is, I really wouldnt attack it unless you have experience in what you are doing, OR have many years spare to learn what to do.

I amnot an expert on porting engines, my terminology might be off because english is not my first language.

I have a degree on mechanical engineering and as i stated, i already ported a Dodge Neon SOHC engine before, it was quite an easy job because on the exhaust ports it has these huge humps (for coolant) that could almost gotten flat without reaching the coolant lines.

My co-driver owns a machine shop so we are not experts but neither dummies with a dremel, all im looking out is for proof and error pointers here, like for example if i only should port to match the gasket or i can go and port X milimiters more.

Also i dont know how the ports of the 172 engine look like, do they have atributte that will generate turbulence so i dont have problems with the ports and chamber being too polished?.

Anyone with experience in this could give me just a few pointers so i dont over do the job, (i dont mind not reaching peak performance since its only to level the field against the other f**king cheaters in the N group)

 

[Andyman]

Mine set me back £600 iirc with AWT through GDi good few years ago.