12.5 for an N/A multivalve race engine is nothing unusual, high for a road car though.

 

Some poorly attempted lowbrow humour but true also.

 

Taxi!!

 

Any higher and I think it needed running on 100RON.

 

Elaborate?

DERV?

 

DERV, correct.

 

I think he has one of them diesel things mate

 

EDIT, as already said above always a few posts behind the game me!

 

Cvh is the way I want to go building a zetec turbo for my mrs puma. Want stay with that engine. After reading what stu Collins has done an seeing it also Christian. Also jimbo had had good results. Just want find out me options

 

Well what power do you want? Are you prepared to convert to efi?

The above two in my book will dictate what compression ratio you should have. Id you sticking with mfi, and your happy with 200(ish) bhp then standard comp is fine.

Rob,

 

Gotech or omex. Want good strong torque curve and reliable. Lol. Around 260lb of torque possibly. I already have ported head an power engineering cam by not fussed if got to change that

 

for my next project im going to see how much power i can get out of a 1.1 ohv turbo! forged crank, rods, pistons, mls HG, ported head, wild cam and massive turbo, it will be ace!

 

Yea funny mate

 

lol, a 950cc would be even better

 

If it were me i would settle for standard compression, my car has a lower compression ratio of around 8:1 and tbh i really don't think it was necessary, especially if its being well mapped.

Just my opinion of course, ideally talk to a decent tuner and see what they recommend.

Rob,

 

300bhp on stock CR is fine so unless you want more leave it as is, you'll just be losing power, response and torque otherwise.
Stu's engine of course make well over that at higher than stock CR but thats not something everyone can do!

 

What sort of boost is on the limit of stock comp? I guess unlimited (within reason) providing the fuel is there? Im on a stock bottom end running 0.8bar atm - wooo lol! But eventually i'd like to go for 1.3bar around 18psi held boost!

 

Cant really answer that becaue boost is relative to an engines VE, on a stock engine it could be 30psi for example but on another engine with a ported cam'd head, custom manifolds and a big arse turbo it could only be 20psi...

 

Ah ic.. But 18psi on a stock bottom end should be ok? I always thought over a certain boost level you'd have to go low comp!

 

Again it depends on what turbo your running, a stock T3 yes no problem as you'll be making about 180bhp, but a T34 at 18psi for example and you'll be making nearer 300bhp so no! lol
Dont think of it in terms of boost because thats relative, think of it in terms of power... Stock bottom end will handle about 240bhp with a sensible rev limit.

 

Ok fine... That makes sense - i see what you mean now! Well i'll be chuffed with 180bhp, so i guess im safe-ish there!

 

interesting subject. mark is building my 2.4 engine at the mo that will be running circa 2.2bar with 9.2:1 c/r ( gt40sized turbo )
now i dont fully understand all of this compression malarky, but he seems more than happy with the spec and the safety aspects so i'm happy to let him crack on.
( evo engine btw )

 

So benefits in general terms of a high compression over a low is..............................

 

As Rod correctly said, if the engine is specced correctly then the compression ratio won't be a compromise

I'm going to be a twat and say... It's only relative depending on other factors