raised comp ratio?

corsaZ22se

how much will I need to skim a standard z22se head by to raise compression ratio for running 267 degree cams?
ive read that it needs to go up to 11.75:1 for a smooth idle, is this correct?
will I need to alter the valve relief's in the tops of the piston too?

evocarlos

best person i can think to ask is @[deleted] and im sure i read that 11.x:1 is 1mm ??
and vocky are you running 266° cams

vocky

11:1 CR is a good option, but it will not make the tickover smoother with high lift cams. Only itb's can do that

corsaZ22se

is that due to the way the standard throttle body controls the idle speed? the stepper motors are quiet weak on standard throttle bodies, I did have dbilas cams in for a while but the idle was terrible below 2500. really good torque though.
the cams ive been looking at are the same lift as the shrick ones but longer duration.

vocky

stage 1 compcams are ideal, give a slightly rough idle, but if you remove the balancer shafts it will be less noticeable.

It's just the extra valve overlap at lower rpm which causes the rough idle.

corsaZ22se

I was told that running big cams in the x20xev I would get a smooth idle, running 280 degree cams with smooth idle.
anybody tried using a cable throttle on a z22se? far more responsive than fly by wire. less to go wrong too.
want to weigh up all the options before I start the work so I can get the best out of it first time.
car needs to be very drivable and has to have idle control for air con and for use in cold weather.

vocky

standard cams are 244 on the z22se, even the stage 3 are only 268 o_O

corsaZ22se

266 isn't that much really, did look into building it as a track car when I started it but its not right for that. plus I want to keep it road legal and to much over lap makes that hard. its all about getting the right matched set up of throttle, manifold, cams, head work, valve size, comp ratio. cracked it with the x20xev so given time and enough research i'll get there with the z22se.

vocky

plenty of info on here, my latest 2.5 throttle bodied engine is pushing over 250bhp so anything is possible (y)

corsaZ22se

not much for a 2.5L? I know they are very capable engines, Vauxhall wouldn't have used them in the btcc for so many years if they were no good.
pushing 300bhp in 2.0L form n/a.
many big name tuners told me I wouldn't get over 180bhp from the x20xev, ended up at 226bhp with mild cams and a 12:1 comp ratio and its just about road legal. 🙂
i'll get her how I want one day! no rush!!:LOL:

vocky

The biggest problem I have is the 2.2 stage 3 cams are rather mild for my 2.5 engine, so unless I get some custom cams then I cannot get serious bhp from it.

But it is a sweet engine so I'm in no hurry to do any more this year.

corsaZ22se

ive found 277 degree cams of the shelf for the z22se.

vocky

where ?

all the supposed high lift z22se cams I've seen are actually for the cast iron x22xe (n)

corsaZ22se

cat cams. not high lift just longer duration. high lift cams require major head work and much larger valves together with 13.5:1 comp ratio or more. then you really are in to race built engine tune levels. no longer road legal.