Modified cylinder heads

[Keyser Soze]

Why do I never see people on here running ported and polished heads?
Are the gains not worth the cost?

 

[SharkyUK]

Some folks running the more expensive engine builds have had this done as far as I am aware (more so with the high-compression builds I believe). Unless you're spending big and looking to go ahead with some serious engine mod's then there's little gains to be had from porting and polishing alone (especially when you factor in the costs of said work).

 

[James]

Why do I never see people on here running ported and polished heads?
Are the gains not worth the cost?

Also I think its been said on here that they're already fairly good from the factory

 

[Fred@BTM]

by the time its done (properly) you'll be £1500+ as a mod on its own its not worth it, with cams yadayadayada then yeah

 

[Ph1 Tom]

Well if flow is anything to go by there are significant improvements possible

http://www.cncheads.co.uk/?p=777

On the Zetec engines I'm used to tuning I've had 12bhp increase at the wheels in back to back testing with 270deg and 10.8mm lift cams. The F4R runs a decent duration and lift so I'd expect to see decent gains based on the flow figures above.

My headwork has carried out by AL Developments and I'm tempted to get my F4R head done as he's doing a group buy on headwork at the moment for £300.

This is his website http://www.aldevelopments.com/

 

[Chip-mk1]

Well if flow is anything to go by

Flow figures will always tell you a bigger pipe flows better than a smaller one, that doesnt mean a bigger port will always make a better torque delivery though, and in fact often the opposite is the case.

Gains from a ported head on an F4R are pretty modest generally as the head is quite good anyway, but they are there especially when using cams and bodies.

I would personally go for someone like Neil Roper (his work is available from MWM more easily than directly a lot of the time as he is quite busy but Mike deals with someone who gets a lot of work done by him so can often get in it at short notice) rather than one of the machine porting companies out there.

 

[Ph1 Tom]

The guy I deal with has done a couple of F4R heads, and the reply on gains were, and I quote. "12 bhp on a standard engine and 18 on a modified engine on ITB's"

I'd be interested to see the before and after graphs for those engines.


On my zetec the biggest difference I noticed apart form the peak power difference was the increase in the spread of torque.

 

[Chip-mk1]

The guy I deal with has done a couple of F4R heads, and the reply on gains were, and I quote. "nonsense"

EFA


No way is a standard clio engine on the restrictive stock cams and inlet and and exhaust etc going to pick up 12bhp from just a ported head!

 

[Adamio]

Mine needed a rebuild so i sent it off to APD along with the inlet manifolds for matching, headwork and rebuild (i'm running Schrick cams)

Can't comment on the difference in performance yet as it's still off the road but as Fred says it wasn't cheap

 

[Dan519]

I usually see decent torque improvements over a good rev range. It's not a power mod, but worth doing along with other things, especially if the head is off for something else. Wouldn't bother with it as a stand alone modification.