Xu9j4rs Hybrid Or Xu10j4rs?

[spike 1]

I've just had a discussion with my customer who owns the 205 Mi16 rally car about maybe building a XU9J4RS engine using the current alloy block and a GTi6 head to overcome the oil surge problem. He asked why don't we use a GTi6 engine complete? The only negative i could think of was the weight difference of the blocks.

I said the difference was about 20kg.

Does anyone know the exact difference in weight of an undressed alloy block compared to an iron block?

Are there any other weaknesses in the GTi6 engine?

 

Thanks

 

Mike

[welshpug 1,623]

Using a different head does not overcome oil surge, seeing as oil surge occurs in the sump.

 

No weaknesses in the gti6 engine that you'd overcome by using the XU9 block, just pay attention to valve clearance.

[brumster 135 1 Cars]

I remember asking this one in a thread of mine when I moved to the XU10 in my rally car; I think it was actually just under 20Kg (16 or 18?).

 

With the XU9, you might be lighter but you are, of course, down 100cc already. If you plan to recoup that lost capacity you're talking custom liners, and the price then starts to take a hoik in the northerly direction, along with custom pistons/rods to get the compression right. All for saving 16-20Kg? Maybe for the uber-competitive millionaire who's after every last tenth.

 

Probably worth skimming my old thread :- http://forum.205gtidrivers.com/index.php?showtopic=109949

 

...contains some of my thoughts on the weight difference and effect of moving from an XU9 to an XU10....

 

Cheers,

Dan

Edited January 17, 2011 by brumster

[markw 1]

Spike,

 

I went for the hybrid route for my competetion car, and have to say it was a pain in the ar$e,

the head and block go tpgether ok, I used the mi head gasket, but its when you come to the

coolant and oil breather hoses that things start to get difficult, not to mention the bastardising

you have to do to both mi and gti6 cam covers to get them to work.

 

dont get me wrong its not impossible and it has been covered plenty on here, its not as simple as

a doner engine change

 

cheers

 

Mark

[spike 1]

Thanks for the replies.

Welshpug, i know oil surge occurs in the sump but the Mi16 head is the cause of the lack of oil in the sump which causes oil starvation. Probably poorly worded on my part!

Brumster,I read your thread,very interesting. Why did you fit the brace plate when you fitted the steel sump? I thought it was only needed to strengthen alloy blocks?

Markw,good to hear some first hand experience of the hybrid engine.

I think i'll start looking for a GTi6 engine!!

[brumster 135 1 Cars]

Brumster,I read your thread,very interesting. Why did you fit the brace plate when you fitted the steel sump? I thought it was only needed to strengthen alloy blocks?

 

The PTS baffle won't fit without it; the sump won't be deep enough (effectively). I took the cross-braces out so all the plate was really doing was effectively being a spacer.

[petert 554]

Just use the whole XU10J4RS engine. The difference in weight is more than offset by the torque/hp gained by the extra 100cc.

[spike 1]

Just so i'm sure,does the XU10J4RS suffer from any oil starvation/surge when used on a slick shod rally car if fitted with a sump baffle?

 

Cheers

Mike

[brumster 135 1 Cars]

My non-RS doesn't, so I seriously doubt a gti6 would...

[Hilgie 16 2 Cars]

Weight differences betweein iron and alloy:

 

Cast iron, no crank, no pistons:

 

Alloy, no crank, no pistons:

[welshpug 1,623]

So 18 kilos on the nose then Both Mi16's Hilgie? just wondering if the 8v and XU7 are any different, but can't see it being much at all.

 

cranks pistons and rods need to be taken into account too, I have some to hand I can weigh