what compression ratio?

jwalker

Looking for a definite answer on this, what is the best CR on a supercharged 2.2?

I read something to say that the earlier conversions ran a lower CR (8.9:1?) but nowadays this is closer to standard?

What sized pistons would be best then, the 8.9:1 oversized ones or something to give a higher CR?

Thanks

vocky

the early conversions were about 8.5:1

cms restrict the power on standard compression cars, somewhere around 240bhp

the wiseco 8.9:1 oversized pistons can take over 400bhp and be safely mapped without risk of detonation

so my advice is either stick to 240bhp or fit lower compression forged pistons like the wiseco 8.9's

JohnnyN

8.5:1 on mine. Ye Olde conversion.

jwalker

Thanks, that gives me something to look at :thumbup:

On a side note Johnny, how much was your pro alloy rad?

JohnnyN

Just had a look through all my paperwork and on the invoice breakdown it doesn't list the pro alloy rad as a seperate item. Its been lumped in under the conversion total. Pottsey (Jason) may have had a quote from Pro Alloy though. I know that he tried to contact them a few times for a price for his Vectra. What car is it that you have? There will be different shapes and sizes according to which car its going into.

Just looked at this on the Courtenay website. It appears to be for a vx220 and is £440. Gives you a rough idea.

http://www.courtenaysport.co.uk/buy-onl ... d_897.html

:thumbup:

pottsey

i gave up trying to get the price off pro alloy lol.but upon speaking with mark watts a few weeks ago i said to him about when i rang pro alloy for the price/paper work on the c/c ,he said its doubtful thery would have the details as when they done yours johnny they measured up the dimensions etc and just passed them onto pro alloy and told them to get on with it ,thats probably why pro alloy couldnt find anything as courtenays had it all.
oh well never mind im sorted now fingers crossed