I use Tesco 99ron, wondering what's generally accepted as the highest compression to safely run on an n/a engine. Thinking of upping mine.

 

Depends on alot of things like the design of the combustion chamber, design of the tops of the pistons, ect

 

it does depend on alot, but 11:1 shouldn't be too bad, 12:1 would need a lot of timing taking out of the map though.

 

I ran 12.5:1 on Tesco 99. The option was there to run 13.5:1 but would need to swap to carless.

 

Engine is a Toyota 4age 20v. It's 11:1 as standard. I've got some updated cams to go in and was thinking of raising the compression to about 11.5:1, maybe more.

 

12:1 isn't to high but as said would need mapping to suit

I have one built for 13:1 but dont think it's gona like pump fuel.

 

I know of XE's running 13:1

 

Very dependant on the cams you are using, 13:1 or even 14:1 or more on lairy cams isnt a problem as your dynamic compression ratio will be so low anyway.

Ask your cam manufacturer what they recomend, its pointless asking anyone else!