Rr Results Xu7j4rs

[Revant01 0]

I guess if the xu7 head was ported to suit the spec of the engine it would be better but it all comes down to budget, my engine with the rebuilt head, belts and gaskets cost less than to get the xu7 head ported

 

Have you seen Dixon's build topic that will give you an idea of what can be achieved with a bigger budget.

 

Yes I have seen that, but I am not thinking anything like that special or big budget. I was just considering the standard GTi6 parts in the XU7 head compared to the full GTi6 head swap. But with the inlet restrictions removed from the xu7 head.

[Sandy 189]

For a straight forward fast road/trackday engine, the GTI6 head is a easier, simpler route. I like the XU7 head, because there's so much material, you can create the inlet port size and shape you want to suit the overall strategy. The XU10 inlet ports are all quite big to start with, so you're very limited in what you can do, although they're clearly already pretty good to start with! This sort of detail is a factor when you have a clear idea of how you want the engine to perform and what you need to achieve that; but if you're already working with compromises, such as less than ideal CR, the OE GTI6 exhaust manifold, vague cam choice, maybe single inlet or so on, then that sort of refinement of the package is a bit pointless. I mean that in the nicest possible way!

Most head porting types will probably pull faces at you when presented with the XU7J4 head, because it's alot of work to make good, there's alot of material to remove. Most modern heads can be "ported" to a standard most people will be pleased with, simply by removing edges and taping/flap wheeling the ports to a sexy finish. So the prospect of sculpting a port almost from scratch, is a labour of love really rather than whirr-buzz-cash.

[24seven 104]

Good result there. I've been thinking about this spec for my next engine once I'm done with Mi16s and their oil surge, but reading this thread confirms I'll be going down this route once funds allow. Would it be worth trying to bring the comp ratio up a little as iirc the standard XU7 pistons have a fair dish to them?

[welshpug 1,622]

no dish on the XU7JP4 pistons, only 4 cutouts and a 10.4 compression ratio.

 

I cant remember if they come up right to deck or not, I didn't take note of that when I took mine apart, if there is any you could get the block and liners decked, though you may well need the cutouts made deeper to compensate.

Edited September 29, 2009 by welshpug

[Sandy 189]

It would, but it's an epic, there isn't a simple piston choice and you'd need rods really too, there isn't quite enough meat in the little end to bush them, unless you reduced the pin size.

[James_R 3]

I think there is a small dish in the std XU7 pistons, I'll grab some pics when I get the head pulled off mine.

[welshpug 1,622]

just checked back, there is a very small dish, details here -

 

http://forum.205gtidrivers.com/index.php?showtopic=84170

 

an Mi16 piston, if you get it to fit the rods or get rods to fit will sit a little bit under deck though they are flat topped.

Edited September 29, 2009 by welshpug