What octane should i run on a 11:8 cr on track day? Temps around here are usually lower 90's.

 

run some race gas if you can....cant hurt, i guess it depends on the timing you are trying to run

 

Depending on what DCR you're getting from your cam, I'd say 95-98. You might even get by with less octane if you have a really late closing intake valve. For comparison, I was running 11.1:1 and had a DCR of 8.25:1 and didnt have any ping with 90 octane. Water temps were 180deg. and I think the air temps were about 70's. Hotter weather I was running 92 and 93 octane.

 

Would i be able to get away with 2gal of 93 and 1gal of 110 on track day? Also is it ok to mix leaded with unleaded.

 

umm, depending on the densities of the two fuels, one might float on top of the other. i would say no to mixing the fuels because you would probably end up using the leaded up then using the 93 cuz the leaded sink to the bottom of the tank. i think it would be ok to mix 2 different types of unleaded fuels though if you mixed 2 gals of 93 then 1.5 of some 105 unleaded or something

 

Cool thanks for the help guys.

 

Simple. Run the lowest octane you can without any knock at that particular temp and DA. Lower octane gas makes a bigger bang.

 

Running unnecessary high octane could have adverse effect and lower performance.
What is your DCR?

I run 94 Octane on 8.65 DCR and 11.75 SCR with no issues, and believe me 90* would be cool here.

Also running 1 step colder plug helps a lot.