Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Comp ratio on boosted 86

General Engine Building Discussion

Forum Posts



Tech Articles

Talk about engine building here. New products, tricky questions or showcase your work - If it's engine building related it's welcome here.

= Resolved threads


Hey guys, I have a boosted 86 currently stock but am looking at building/buying a built short block. However im a bit stuck on what CR I want to run. Currently the high CR dosent seem to bother it to much on 6psi but im looking at putting the smallest pully on my Supercharger to get around 18ish psi and ill defs be flex fueling and running a boost controller for when im not using e85. I just want to know everyones opinion on what CR they think will be good and any tips and feedback from your own experiences would be appreciated. (Im looking more at IAG shortblocks which are 12.5:1 or 10:1)

Thanks in advance everyone! :D

Hi Brandon personal experience is 10:1 is great on these builds it gives the flexibility to be tuned on pump gas as well

Regards Ross

Thanks heaps mate, I think because im doing it as my daily I might do that so then I dont have to buy a boost controller aswell. :P might make it a bit more reliable considering tuners in my area are questionable at the moment.

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?