3 replies to this topic

[TedKarslake]

I'm building a 998cc turbo, and have found some dished pistons online which say they will lower the CR to 8:8:1... Is this okay to be running a turbo?

 

Thanks,

Ted

[coopdog]

I'm building a 998cc turbo, and have found some dished pistons online which say they will lower the CR to 8:8:1... Is this okay to be running a turbo?
 
Thanks,

Ted

Well I'm running about 9:0 with 7psi and a basic map and I'm about 90bhp, will be turning it up to around 14psi for about 120bhp but this is with a big intercooler and ecu to help but this cr is a little high, 8:8:1 gives you a bit more safety.

Get over to turbo minis and have a look and it should help a lot

[Dusky]

They won't lower it to 8.8:1 as no engine is the same.

Measure everything, then calc your comp ratio from that.

[BaileyPerformance]

the best CR for a turbo engine depends on boost, IAT and cam spec. Not to mention ignition control.

 

if you are going basic setup (carb /dizzy) with stock 998 cam and low boost (<8psi) then stock CR if fine assuming you have a decent intercooler.

 

running a hotting cam allows higher static CR with same boost and will give a lot more power.

 

my advise would be keep CR stock, good head and cam and keep boost lowish. You will end up with the same power is if you went low CR and more boost. Advantage is the high CR gives better MPG and throttle response (less lag)