Downdraft Sri Head Vs 205gti Head

[veloce200 3]

isn't there gojng to be the same block to head fitting issue as with the XU10 head onto the XU9 block ?

the issue with the XU10 was it was designed for a larger bore. this should be a straight swap (upgrade hopefully!) as long as I use flat top pistons. probably need quite a big skim on the head though.

 

 

the issue with the XU10 was it was designed for a larger bore. this should be a straight swap (upgrade hopefully!) as long as I use flat top pistons. probably need quite a big skim on the head though.

 

 

erm i've just noticed something - any ideas where the thermostat goes ? also is the dizzy end the same as XU9JA?

[rich_w 0]

The 405 SRI used a coil pack, not a dizzy, I don't know if the water housing on the end is interchangable, but as I have a SRI and a std XU9 I might just be able to find out

[Anthony 1,003]

The 405 SRI used a coil pack, not a dizzy, I don't know if the water housing on the end is interchangable, but as I have a SRI and a std XU9 I might just be able to find out

Actually, early 405 SRi's used a dizzy and later ones a wasted-spark coilpack.

 

The thermostat housing are interchangeable though, so no problems there

[veloce200 3]

Actually, early 405 SRi's used a dizzy and later ones a wasted-spark coilpack.

 

The thermostat housing are interchangeable though, so no problems there

from the picture I can't see a thermo housing - pretty sure (but not got the car here) that on the XU9JA the housing is on the front like the XU10 in the picture. XU9J2 appears to have no housing?

Do you think I will be able to connect my dizzy to the head ?

[pug_ham 244 3 Cars]

isn't there gojng to be the same block to head fitting issue as with the XU10 head onto the XU9 block ?

Not really, if used on an 86mm bore XU10 bottom end then the chamber could be opened out to suit & if used on an XU5/9 the bore size is the same at 83mm.

 

There isn't a thermostat / dizzy housing on the head, I used it for my car when I fitted the coilpack but the one from an XU9 will fit straight on with a new gasket.

1339 41 01 HOUSING SEAL

A003 WITH ASBESTOS

UP TO 12/1990

 

1340 08 01 HOUSING SEAL

A005 WITHOUT ASBESTOS

UP TO 12/1990

The cam in the XU9J2 head has the slot for the dizzy in, presumably from when the SRi's ran one.

 

Graham.

[veloce200 3]

Not really, if used on an 86mm bore XU10 bottom end then the chamber could be opened out to suit & if used on an XU5/9 the bore size is the same at 83mm.

 

There isn't a thermostat / dizzy housing on the head, I used it for my car when I fitted the coilpack but the one from an XU9 will fit straight on with a new gasket.

1339 41 01 HOUSING SEAL

A003 WITH ASBESTOS

UP TO 12/1990

 

1340 08 01 HOUSING SEAL

A005 WITHOUT ASBESTOS

UP TO 12/1990

The cam in the XU9J2 head has the slot for the dizzy in, presumably from when the SRi's ran one.

 

Graham.

 

great thanks. roll on 180 bhp on a budget!

[Guest andy309goodwood]

i dont know what size valves he has fitted how ever i will be more than happly to messure them for you when it arives

im hopeing to be picking it up in the next few weeks

 

 

how ever i have asked him to optomise it for forced induction and he has made the valves to suit the custom cam

yes made lol

[Mattsav 1]

You should be able to get the ports to 35mm on the downdraft head.

 

It will be close though.

[Guest andy309goodwood]

should be interesting and cheers for sorcing the cam matt

[Pug_101 0]

Yeah actually just to call it "XU9J2 head" is better because it was in the GTX and GRI 405 as well as the SRi.

 

After following this thread I am thinking of do this head conversion to the standard GTi engine XU9J1.

The difference with my build is I plan on keeping as much as possible standard GTi such as exhaust, intake,ecu, throttle body etc, so this would give a clear answer to the question "Sri Head Vs 205GTi Head", in it's standard form at least. It would be great if some of you could help out in this mainly with finding parts, part No's (as I haven't a clue) and info on the finer details.

Idealy I would just take the head off my current engine and fit the standard XU9J2 head with the GTi cam in it.

Ok I know the intake manifold is different so either use the SRi one or modify a GTi one to fit (would like to keep the injectors and throttle body at least) & the exhaust manifold is different do you think it will fit straight to the GTi exhaust system?

I need to swap over my dizzy and sort out the rocker cover.

The main concern with this project from what i've gathered is the cylinder compressions. So to get round this and give a fair result I was thinking If I measured the combustion chambers in the SRi head then either took the head off the GTi and measured them or used a reference figure for the volumes of the GTi head (Save taking off twice or having the car off the road) then it should be possible to work out how much to skim the SRi head by, therefore when placed on the GTi block CR should be the same.

Is there anything i've overlooked?

How to test the result. well all I can think of is timing my cars in gear acceleration, as standing starts and gearchanges can have a big affect on timed runs. I could time 50-70mph runs in 4th & 5th gears.

If anyone knows of a friendly rolling road owner who would test it for free, in the name of science of course I'm up for that.

How does this sound to you?

veloce200 I am not trying to hijack your thread, but seeing as your looking to do 180bhp with this head it might be a good idea to compare it's benefits in standard form too.

 

Paul

[Dom9 2]

There is NO WAY you can modify the GTI inlet to fit the SRi head... Well, I'm 99.9999% sure of it at least... Stick with the SRi manifold and go from there...

 

You will need to skim a hell of a lot o fmetal from the head face of the SRi head to get the compression to a reasonable figure, but it may be possible... If you are going to this much trouble, you might as well have the valves and seats modified and maybe some porting done... Yes, it's nice to have a standard reference but if you want more power later on then you have to take the head off again and change the gaskets and strip the head down, which is yet more expense!

 

Just my 2p!

[veloce200 3]

veloce200 I am not trying to hijack your thread, but seeing as your looking to do 180bhp with this head it might be a good idea to compare it's benefits in standard form too.

 

Paul

 

no worries ! I think the exhaust side of the head is the same though? round ports and spacing looks the same. Certainly you'd need the 405 inlet manifold. In a way Peugeot has already done the work for us - the 405 puts out about 9lb more peak torque with a milder cam and less compression.

so the std 205 puts out 130hp @ 6000 rpm this is 59lb torque per litre.

SRI put out 125 hp @5500rpm this is 63lb torque per litre.

 

So if the 205 put of 63lb torque per litre with this head and 205 cam you might expect to see - 136 hp with no other mods. Maybe more as the 405 figure is with a very mild cam - it's got no lift at TDC that I could see. Personally for road use the XU10 is the better bet - my reasoning is XU10 with 12:1 compression is likely to blow gaskets and for this reason I want to avoid it. XU10 would be a lot less work and I think you'd get as good or more power than an unmodified XU9J2.

[sorrentoaddict 1]

just to confirm, has anybody ever seen a square-inlet-port XU9 head, that has factory fitted 42.5 mm inlet valves AND XU10-J2-style chambers ?

 

I am 99,99% sure that there is a third (or fourth?) sub-version of the XU9-head designs. My own GTI1.9 (German market, Motronic) runs a "dead" ign. distributor and a Catalyst, and is listed as a XU9-JAZ, whereas there is a clear XU9-JAZ (but with different D.. Citroen identification??) fitted to some late-ish BX GTi models, and it clearly runs the same MOTRONIC spec. as on my car, BUT with the weird, curved Inlet Manifold AND with the downdraught inlet ports (referred to as "SRI-head" on this forum).

 

I firmly believe that if we had more members from continental europe, as opposed to UK-market-specced-cars-knowledge, this would be somewhat clearer, as I have seen myself such a head, unfortunately no clue as to what car it belonged from factory?! (in any case 99% chances are it was fitted to a BX).

 

Sorry for the hijack.

 

 

Cheers

 

 

Alex

[veloce200 3]

just to confirm, has anybody ever seen a square-inlet-port XU9 head, that has factory fitted 42.5 mm inlet valves AND XU10-J2-style chambers ?

 

no but I'd like one please !

[Pug_101 0]

Personally for road use the XU10 is the better bet - my reasoning is XU10 with 12:1 compression is likely to blow gaskets and for this reason I want to avoid it. XU10 would be a lot less work and I think you'd get as good or more power than an unmodified XU9J2.

 

Ok thanks for that.

All the models of XU10 heads the same, ie: j4r,j4,j2?

 

Paul

[speedy 2]

I checked for some info for you people on this.

 

My ex 205 had an sri engine and it fitted fine altough i did have an auto bonnet on it. The standard engine IMO is better than a gti 1.9 unit. More torque ideal for hillclimb events ( and that is what my car was built for ... not by me i got it after they crashed it).

 

I sold this engine since i wanted to fit the mi16 to another guy who was going to race in hillclimb events and he started tuning it. it DOES rev and dyno figures impressed me since i never taught you could get 200bhp ( 198bhp @ 7200 rpm) for the 8v motor with standard capacity?

 

i know for sure he has an emerald ECU , 45mm jenveys, custom cams( made locally), 300cc injectors, waisted spark, there was a lot of headwork for example i know for sure as i saw it there is an extension betwen the inlet an exhaust valves to raise compretion..... which is pretty high. the bottom end has just been blue printed but still on standard components.

[pug_ham 244 3 Cars]

All the models of XU10 heads the same, ie: j4r,j4,j2?

J2 only, J4 is usually the 16v engines faik.

 

Graham.

[gti_al 1]

Just reading through this, your build is sounding like the one i have been thinking about lately. Basically i want more than the 74kw my low comp 205 had when it left the factory, (god knows how many are left after 260 000kms...) but i would like to stay 8 valve for occasional competitions i may want to enter.

 

This XU10 head must be the one found on 2L 405s - yes? Judging by the amound of references to it i presume it fits on without too many issues?

 

Also, i was thinking that having a crack at bike t/bs wouldn't be a bad idea, although the manifold is an issue. Has anyone got a pic of a standard xu10 mani - or even any 8 valve t/b manifold?

[veloce200 3]

Just reading through this, your build is sounding like the one i have been thinking about lately. Basically i want more than the 74kw my low comp 205 had when it left the factory, (god knows how many are left after 260 000kms...) but i would like to stay 8 valve for occasional competitions i may want to enter.

 

This XU10 head must be the one found on 2L 405s - yes? Judging by the amound of references to it i presume it fits on without too many issues?

 

Also, i was thinking that having a crack at bike t/bs wouldn't be a bad idea, although the manifold is an issue. Has anyone got a pic of a standard xu10 mani - or even any 8 valve t/b manifold?

 

 

AFAIK the XU9J2 is the only one with the downdraft inlet port. I think but an not sure that all XU10 have the sidedraft port. KW's - are we talking lawnmowers or engines here? (long live HP and Lb/ft !)

 

XU10 would be the favoured option for sub 10.5:1 compression IMO on an alloy block for budget power. I want to run a "grenade" spec to keep up with these minted 16valve owners so I'd rather blow a rod through the block than blow the gasket - XU10 onto XU9 block seems to work fine but is untested at >11:1 compression

[gti_al 1]

The kw issue is interesting... I don't know why, but everyone seems to refer to the low comp gti engine in kw, but the proper one in hp.

 

Anyway, (sorry that this is going off your original topic) but why is the Xu10 head is better? All i can find are references to it, with no explaination of why it is good...

 

Good luck with your engine though, it sounds promising. I will be really interested to see how you go with the bike t/bs, if you do end up using them.

[Pug_101 0]

Anyway, (sorry that this is going off your original topic) but why is the Xu10 head is better? All i can find are references to it, with no explaination of why it is good...

 

 

Check this thread out if you have not already done so:

http://forum.205gtidrivers.com/index.php?showtopic=45453&hl=

 

Basically the head flows better as standard so more power can be achieved.