Xu10 Head On My 8v?

[mad_dome 1]

Was going to put new head onto my 8v. It had just been ported and polished but alot of people said this would not make much diffrence.

so a mate of mine suggested the xu10 head because it has bigger valves. Is this a wise choice? and whould it work well with my 270 piper cam and group a injectors? any help much appriciated. cheers

[Miles 331 1 Cars]

I'd stick with the std XU5/9 head as it's generally better, The XU 10 has smaller exhaust valves and a bigger inlet but the problem you'll have is the XU10 head is designed for a 86mm bore and not a 83mm bore

[mad_dome 1]

but i here you can get 150bhp with the xu10 head is this right?

[Miles 331 1 Cars]

You can get 230bhp from a XU5/9 head, so take your choice

[ifcho 0]

so your advise is really not to use xu10 heads?

 

I am thinking of them, cause I'm doing a throttle body conversion, and I think that the round ports of the xu10 head, may suit the bodies better than the rectangular ports of the xu5/xu9?

[tom_m 0]

so your advise is really not to use xu10 heads?

 

I am thinking of them, cause I'm doing a throttle body conversion, and I think that the round ports of the xu10 head, may suit the bodies better than the rectangular ports of the xu5/xu9?

 

only if you can find a manifold with round ports. all the ones i've seen are square port designed with the xu9 head in mind.

[ifcho 0]

i have to build a manifold by myself unfortunately. I do not have the finances for a custom manifold (they are quite expensive in the UK) and no one is doing such things here (in Bulgaria)

[mad_dome 1]

You can get 230bhp from a XU5/9 head, so take your choice

 

 

Miles how is this possible???? Iv heared that the xu10 head has bigger valves tho and you can use a more mappable ecu from the 406 to get the setup spot on! but i am now thinking use this head for abit with all my other mods and then just gti6 it with TB's.

[ifcho 0]

the xu10 head has bigger inlet valves, but smaller exhaust valves.

The problem with it is that it is designed for larger bore, and I guess the squish zone? is not very nice when using this head.

Additionally there may be some sealing problems because of the larger bore.

 

There isn't a difference from the point of engine management, which head you will be using..

 

In the UK I guess there are plenty of engine builders who can do miracles with the xu9 head....too bad we do not have such ones over here

 

If you are not limited in capacity by some race regulations, I guess the gti-6 route is the best one.

[DrSarty 90 1 Cars]

I do not have the finances for a custom manifold (they are quite expensive in the UK)

 

You can't rustle up about £150? Bogg Bros, or even (if he has the time spare) Colin Satchell aka eeyore on this forum could do it for you.

 

What price did you have in mind for a custom manifold?

[ifcho 0]

well...150 pounds is about 200 euros for a piece of metal..my engine build has already gone well over budget now, .and from the topics I have found here not all examples have been very nice made...

 

the custom one I will make will cost me less than 50 euros...cut the flange of the standart manifold, weld four pieces of alu pipe to it at slight angle and attach the bike bodies with rubber hoses.

At the end where the pipes meet the flange, I will add some additional welds from the inside, so after polishing/porting the welds I cane make a transition from the round section of the pipe, to the square section of the head...

The xu10 head my save me the hassle for making this transition..but I'm not very keen on this xu10 head actually

 

I'm open for ideas and advices however

[DrSarty 90 1 Cars]

Jees....I thought I was cheap!

 

I admire your efforts to save cash. I've run out too

[ifcho 0]

i must say your perception for money is quite different from mine

In another topic someone said that a pint of beer in a pub is 3-4 pounds?

Well here it is 1 euro in the pub and 0.40 eurocents at the shop

[DrSarty 90 1 Cars]

In another topic someone said that a pint of beer in a [uK]pub is 3-4 pounds?

Well here it is 1 euro in the pub and 0.40 eurocents at the shop

 

Well that's me emigrating to Bulgaria then.

 

I even speak Bulgarian 'NODNOL'. (Anybody get that last bit? )

Edited February 5, 2008 by DrSarty

[ifcho 0]

I doubt that you would like it...although it is full of English tourists here....last weekend at a winter resort here, there were more englishmans than bulgarians ...in pubs/shops you were greeted in English instead of Bg,there were flags of English footbal teams all over the pubs...most of the guys/gals behind the counter were pretty surprised our group is not English as well

 

p.s. I don't get the joke about London

 

We have gone "slightly" offtopic here...to bring the topic back on topic, what is your opinion, should I use xu10 with round ports or the xu9 head?

Edited February 5, 2008 by ifcho

[bobob 0]

I even speak Bulgarian 'NODNOL'. (Anybody get that last bit? )

 

Someones a fan of Red Dwarf then

 

Although I thought that was polandski?

 

 

Sorry not very helpful to your problem.

Edited February 5, 2008 by bobob

[DrSarty 90 1 Cars]

Sorry about the off topic bit Ifcho, but I think your real answer is below, as Miles said:

 

You can get 230bhp from a XU5/9 head, so take your choice

 

Instead of going the whole hog for 230bhp, why not get a very tractable 170ish and not spend ridiculous money or have to buy any new head? Seems wise to me.

[ifcho 0]

actually this thread was not started by me, so must appologize to mad_dome I guess...

 

I'm not going for GTI-6 engine, cause I want to compete in a class, limiting the capacity to 1.6. It will be my first year of racing and I want to start with something smaller...and in the higher group there are some seriously strong kitcars/ex-f2000 cars/etc and in order to be competitive there I will need to put a whole lot of money in my engine...

[mad_dome 1]

Sorry about the off topic bit Ifcho, but I think your real answer is below, as Miles said:

Instead of going the whole hog for 230bhp, why not get a very tractable 170ish and not spend ridiculous money or have to buy any new head? Seems wise to me.

 

What is needed to get this sort of gains sarty??????

[DrSarty 90 1 Cars]

What is needed to get this sort of gains sarty??????

 

I'm afraid the really knowledgable ones (with the experience of using this head) will know such as Miles, Sandy, James R, PeterT etc. I suspect it's a matter of ITBs, cams and a good exhaust. The application for your engine is now pretty clear, now it's just a matter of budget I'm afraid.

[SPGTi 2]

What is needed to get this sort of gains sarty??????

 

 

Very, very deep pockets.

 

Anyway IMHO I still think for budget modification slapping a XU10 head on with a good skim, blending out the inlet ports to match the XU9 inlet manifold and a lumpy cam will give a better increase than spending the same money on a XU5/9 head / cam combination.

If you start looking at flowing, porting the heads and having some serious work done I would say stick with the XU5/9 head.

 

I don't think anyone has done a basic comparison like this before though

 

Steve

[mad_dome 1]

SPGTI this is my point iv got 3 diffrent heads at home xu10,xu5/9 and another one with has been ported and polished etc.

what is for shaw is that my budget is for every increasing and i could never possibly put a price at to were it will stop. but Tb are on the cards for shaw but i think i will try all the heads with TB and my piper 270 cam and have each one tested on the rollers. seems like the easy way to fined out the best possible head for the 8v.

[Alastairh 47]

Anthony on this forum can talk from experience on this one having a Xu10 cylinder head on a Xu9 bottom end installed in one of his cars.

 

Hes not done any rolling roads of before and after, but being out in the car aswell as others its certinly a quick 8 valve fopr little costs.

 

If i had to stay 8 valve because of insurance etc but wanted a cheapish tweak, personally id look into it.

 

Yes you can get 230 bhp Xu9s, but its not really realisitic comment to make for a road car plus the time to develop the engine. What you've got to weigh up though when it comes pointless and just GTI6 it...

 

Al

[mad_dome 1]

thanks for all the help fella's ill go with the xu10 head and let u all no weather it will make a diffrence cheers again!1

[martin81 1]

im gonna do the same convertion, on my 1.9 CTI.. I should increase the bhp from 102 to about 148bhp.. thats about 46 bhp's for about 200-300£.. cheap bhp's

 

Are you sure that the out valves are smaller than original gti?? I think their are bigger than the cti head!!