Idle And Perfomance, 205 Cti?

[martin81 1]

I have a 1,9 cti, and my plans are to put on a xu10 head(inlet port matched), and a fast road cam...

i've found a piper 285, but how will it run and perform.

i've been told to put the ignition a few notches back to avoid detonation.

and i expect it to idle about 1000-1100 rpm's

 

any experience??

 

Martin

[martin81 1]

nobody at all

[Henry Yorke 269 3 Cars]

Not having done this specifically, but I know you need quite a big skim on the head to get the compression down. This puts your timing out, so you need a vernier pully to adjust the cam timing too. I am not sure how the Jetronic system will cope with this modification too (1.9 CTI runs an Jetronic ECU ending in 345 and a matched air flow meter compared to the 1.9 GTI which has motronic)

[martin81 1]

Not having done this specifically, but I know you need quite a big skim on the head to get the compression down. This puts your timing out, so you need a vernier pully to adjust the cam timing too. I am not sure how the Jetronic system will cope with this modification too (1.9 CTI runs an Jetronic ECU ending in 345 and a matched air flow meter compared to the 1.9 GTI which has motronic)

It's been skimmed, but only to level it.. I'm confused about the c/r because if you put a XU head on a normal GTI, which has a c/r at 9,6, then with the xu10head on it would be at about c/r 12.

But the CTI(Rallye) engine runs with a c/r at 8,3 or so, because of different head and(forgot the word in English, but those inside the cylinders, that creates compression)

So by putting on the xu10 head, you'll gain some c/r but not as much as a GTI, because you'll still have the different(same word)

I'll reckon the c/r will be at about 10-11, and that its still controllable.(It's been done without a big skim)

But thanks

I'm more in to experience with the cam itself.. How it runs and performs...

[Henry Yorke 269 3 Cars]

I know when 28Craig put an XU10 head onto a GTI engine, he had to skim a lot off the head (1.2mm seems to ring a bell), in order to get the compression ratio down to a level that performance will be increased. Have a search around the forum as it was a common mod not that long ago.

[28CRAIG 2]

I skimed 1.6mm from my head to get a C/R of around 10.6 not sure of the dome volume on the 1.9 cti pistons but it would be a little higher. I am going to build a new engine and going back to the old xu9 head that was ported and polished as even with a vernier pully i have had to retard the ignition timing right off and the engine just feels very flat and it still pinks in a high gear going up hill.

[martin81 1]

I skimed 1.6mm from my head to get a C/R of around 10.6 not sure of the dome volume on the 1.9 cti pistons but it would be a little higher. I am going to build a new engine and going back to the old xu9 head that was ported and polished as even with a vernier pully i have had to retard the ignition timing right off and the engine just feels very flat and it still pinks in a high gear going up hill.

 

How can it be higher on a cti.. It's 8,4 on cti and 9,6 on gti... the xu10 head increases c/r, so naturally it would increase even more on a gti rather than on the cti.. Or what?