Which Head On Xu7 Block?

[tomcolinjones 26]

Hello everyone! Me again...

 

I shall be starting to build an Engine for my new 205 road / track project soon.

 

I Want to use a rebuilt XU7 block (alloy)

 

I have a 2l mi16 engine and a xu9 8v engine available, Which head to fit?

 

The mi16 head will give me more power obviously but....

I would like to use the 205's 8v ecu and loom to run whichever engine goes in... for now and swap over to aftermarket ecu and loom (emerald e.t.c)

 

Is this just a case of Fitting the gti dizzy, afm and throttle body and de-limit the ecu, or a lot more complicated?

 

The 8v head should bolt streight on and run okay on the 8v ecu ( am i right?)

 

I understand that it would me much easyer to run it on twin 40/45's but as this is mainly going to be a road car i dont want to be doing 10mpg to work!

 

basicaly if anyone has an idea of drveability between both these heads on the 1.8 alloy block, and how simple it would be to get running please post back.

 

 

Thanks muchly

 

Tom

Edited March 31, 2011 by tomcolinjones

[welshpug 1,661]

xsi or gti6 head would do the trick too

 

though I really would save up for the ecu first, so you can concentrate on building the engine properly, not have to bodge about making a dizzy and afm fit.

[tomcolinjones 26]

xsi or gti6 head would do the trick too

 

though I really would save up for the ecu first, so you can concentrate on building the engine properly, not have to bodge about making a dizzy and afm fit.

 

 

GTI6/xu10j4rs head would be nice, but i dont have one available at the moment that whole engine is going in the xs

 

i do fancy the 16 valve route myself!

 

i have a matching loom and ecu for the mi16, could i get this to run the engine with a remap? I will be using a 1.9 16v or gti6 inlet manifold to get rid of the plastic vaccum sphere acav manifold rubbish.

 

How far off mi16 power would you expect it to be WP? is there any reason i wouldnt see up to 30mpg with mi16/vts box? its not the major factor, just would like to know what to expect!

 

[Anthony 1,003]

8v head will go straight on and work fairly well with standard management/dizzy, the only issue being you'll need to knock a bit of advance off due to the compression, but in standard form it won't be amazing as it's still only a 1.8 8v. With a hot-ish cam to take advantage of that compression that combination goes well enough though, even on standard management - do a search for James_R's ill-fated build.

 

I'm pretty sure that an Mi16 or S16 head will give you lower than standard compression as, I believe, the chamber size is about 3-4cc bigger compared to the XU7/XSi/GTi-6 head (which gives 10.4:1 AFAIK). Not ideal, especially if you're likely to fit cams in the future. There's other issues as well, such as timing belt covers and that the timing will be out a few degrees owing to alignment differences between the lower cambelt cog.

 

Best of starting with a XSi or GTi-6 head really I'd have thought, although no management will be ideal for that out of the box.

 

To give you some idea, 28CRAIG on the forum did a XU7 bottom end, GTi-6 head/cams/inlet/exhaust build on DTA management and that got 160hp and 125lbft, although I'm pretty sure that those figures are optimistic, as I've not doubt that there's more power to come as the map that he had done was pretty poor in terms of both fuelling and ignition. Do a search and you'll find some more details of his build.

[tomcolinjones 26]

8v head will go straight on and work fairly well with standard management/dizzy, the only issue being you'll need to knock a bit of advance off due to the compression, but in standard form it won't be amazing as it's still only a 1.8 8v. With a hot-ish cam to take advantage of that compression that combination goes well enough though, even on standard management - do a search for James_R's ill-fated build.

 

 

If i went 8v, could i expect 1.9 power with a big cam? i understand the xu7 is 'oversquare' so it likes to rev... so would it be like a 1.6 with a bit more poke?

yellow 1.9 injectors or (black?) 1.6 injectors?

The 8v will definately be cheaper ; being able to run well on 205 electrics, no problems with fitting exhasuts and i have almost everything to get it working.

 

 

I guess that rules the mi16 head out, trying to sort the timing out sounds a bit beyond me! and no room for errors with so little valve / piston clearence... could get very expensive. think its time to sell the mi16 on and get a cam and a few tyres! Or maybe i should just man up, be a sheep, and fit the whole (iron block) mi16 engine

 

 

 

the other 205 is 16v, so i fancy something different... and there arent many 1.8 8v gti's around AFAIK

[tomcolinjones 26]

I have made a decsision!

 

Firstly I would like to thank Welshpug and Anthony for pointing a few things out, great help

Since the mi16 i have here is rebuilt already (new H/g W/p and C/b+\tensioners) i will fit the whole engine on its own management.

 

a 2l mi16 cant be much more than 20/30kg heavyer than the xu 8v engines. and it is much simpler to fit and get running... just the cooling to wory about.

ill fit gti6 inlet manifold to save faffing around with the acav system. and should get around 30+mpg driven sensibly with the mi16 box

 

And it would be much more fun on the track! 150+hp

 

Also after searching, it seems the 2l mi16/s16 suffer less from the oil surge / starvation problems asociated with the 1.9's

 

Cant wait to get the car and start getting to work!

 

I know its not 'different' like i intended. sometimes cost and mechanical abilities over-rule

Edited April 1, 2011 by tomcolinjones

[Anthony 1,003]

Certainly that route makes the most sense - you already have it sat there ready to go, and doesn't involve spending a significant chunk of extra money

 

I'd argue that in a way an S16 engine is "different" seeing as most people overlook them and go for either a 1.9 Mi16 or GTi-6 engine, which is both a shame and a blessing - it's a shame because it is a good engine in its own right and is tough as old boots (the ACAV and coils less so mind), but a blessing because it means that they're much cheaper to pickup than an equivilent 1.9 Mi16 or GTi-6.

[tomcolinjones 26]

Certainly that route makes the most sense - you already have it sat there ready to go, and doesn't involve spending a significant chunk of extra money

 

I'd argue that in a way an S16 engine is "different" seeing as most people overlook them and go for either a 1.9 Mi16 or GTi-6 engine, which is both a shame and a blessing - it's a shame because it is a good engine in its own right and is tough as old boots (the ACAV and coils less so mind), but a blessing because it means that they're much cheaper to pickup than an equivilent 1.9 Mi16 or GTi-6.

 

I guess there arent many 2.0l mi16s about like you say. Acav can be dealt with, and some new coils should se me relitively trouble free for a while? Looking at other Sorrento builds it seems i have a lot of competition in terms of build quality!

 

May take me a littel while tho... 2 projects on the go at once

[Anthony 1,003]

The only thing I would suggest if it's not been done already is to change the big-end shells, as they are a weak spot on XU10's.

 

They do still suffer oil surge, but they're not as bad as 1.9 Mi16's seeing as they already have the anti-surge features as standard like baffled sump, windage tray (later engines) etc. On the subject of which, if your engine has a tin (rather than alloy) sump it would be wise to whip it off and check that the trap-door in the baffle is still present, as they often had a silly plastic affair that can break / fall off and gives an effectively unbaffled sump. While it's off, take the opportunity to fit a windage tray if your engine is an earlier one that didn't have it as standard - I think this is only the initial engines fitted to the 405 2.0 Mi16's, but no harm in checking.

[tomcolinjones 26]

The only thing I would suggest if it's not been done already is to change the big-end shells, as they are a weak spot on XU10's.

 

They do still suffer oil surge, but they're not as bad as 1.9 Mi16's seeing as they already have the anti-surge features as standard like baffled sump, windage tray (later engines) etc. On the subject of which, if your engine has a tin (rather than alloy) sump it would be wise to whip it off and check that the trap-door in the baffle is still present, as they often had a silly plastic affair that can break / fall off and gives an effectively unbaffled sump. While it's off, take the opportunity to fit a windage tray if your engine is an earlier one that didn't have it as standard - I think this is only the initial engines fitted to the 405 2.0 Mi16's, but no harm in checking.

 

I was planning in whiping the head off and changing over the rings so big end shells can be done at the same time, as well as checking the sump.

Am i correct in thinking i can fit XU10j4rs sump and pump? guessing this would help with oil problems? my MI16 Has an alloy sump BTW.