998 turbo
Turbo Mini Forums

Ive had a look but couldn't find anything about a issue a friend of mine is having so here it is.

Just a general query. I have a 12g295 head, measured the chamber at 28cc so its pretty much untouched. I have a 998 block which is overbored +.030 and the pistons have a (can't quite remember but i think) 6cc dish. I've used an online cal and it gives me a comp. ratio of around 8.5:1

I have been doing a little research and some of the older pre A+ 998's had a comb ratio of 8.3:1. If I were to build this engine as it was, what performance degradation would I have due to the low comb. ratio?

The plan is to eventually go forced induction so I don't want to be skimming the equivalent of a steel rsj of the head to bring the comp. ratio up. Would it be worthwhile building the engine and using it with the low comp. ratio or wait till I can afford to do it all at the same time. (bearing in mind I have a baby due in sept so it might be a while before I can afford to build the engine to the full forced induction beast I want to)


Any help would be appreciated

to make a guess i d say about 4 to 6 bhp on a 50 bhp 998?
id build it low comp and that will spur you on to turbo it .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM