highest compression you can run on pump gas?

[mx Eli]

I was just wondering what is the highest compression you can run on 93 octane no ethonal pump gas. and if a octane booster like the new lucas oil octane booster or similar product actually would work?

I have a buddy who I know runs 93 in his crf hybrid with a 13.5:1 but I wanted to know what you guys think


Thanks for your help

[eastside 400]

typical rule of thumb is 12.5:1 some engines can handle more compression off of pump gas then others

[mx Eli]

could I run 13:1 with some lucas oil octane booster? at a mix of 100:1 it increase 93 octane pump gas to 96.6 octane. and at 50:1 it makes 93 octane 98.4

[JJs450r]

i wouldnt run any octane booster always heard bad stuff about them but i know a lot of people will run pump gas with a 13.5:1

id go 12 if i were gonna run pump gas though

[mx Eli]

yea I don't mind putting a piston in a little more often if I could pump gas because it's so much cheaper.

I have heard bad stuff about the generic brand booster but there was a test on lucas oil octane booster that said it was good stuff here's the link to the test

http://volvospeed.com/Reviews/octane_boosters_lucas.html

I was thinking if I mix one bottle (16oz) to every 10 gallons it would be about 97 octane give or take 1 or 2. or would it be better to run just plain 93 pump gas?

thanks for you guy's help!

[BlaineKaiser450]

Get a 12.5:1 piston and run straight 93. You'll be more than happy

[mx Eli]

well it's actually in a quad I'm looking at but I think I would probably switch it to 12.5 once I get it

[DnB_racing]

I just removed my 13.5 comp piston that I ran a 50/50 mix, 93 octane and c-12 and the piston had around 200 hours, and looked great no pitting, no blow-by on the rings. if I were you I wouldn't run octane boosters but use race fuel to boost your octane

[mx Eli]

ok maybe like a mix of 3/4 pump gas and 1/4 vp 110?

[DnB_racing]

the c-12 has actual at the motor octane number (MON) of 108. A ratio of 3 to 1 with 93 octane would give you just under 98 octane. This is with 93 non ethanol added fuel. Ethanol blend fuels have a higher octane rating, but carry a lower energy content

[Dirtjunkie85]

I have a 13.5:1 piston and just to be safe, i run 100 octane that we have at a local gas station.

[Baileygunns]

You should be able to run some 100LL and be ok... You can run a quality octane boster and be ok too...

100LL is 100 octane low lead. They run in in airplanes and you can usualy find it a local airfields... I can get it for about $4.85 a gal here in Florida. The lead is good for you valves too... Keeps them lubed and helps the top end last longer...