Compression Question

22crazy

Senior Member
what up. Ive been searching the net and asking people but nobody has been able to answer my question. I wouldnt mind building a crazy NA motor but the problem i face is compression vs octane. I no if someone wants to build a NA motor u need high compression, but the problem is that the higher compression u go, the higher octane u need to go. My problem is that in my area the highest octane u can buy at a pump is 94...i can buy octane boosters, but i dont want to buy a booster everytime i go to the pump. Does anyone no whats the highest compression u can have inside your engine using 94 octane before the gas spontaneously explodes because of compression :eek: instead of spark. Thanx
 

xj0hnx

I wanna be sedated
VIP
I mean there is a article about detonation that will give you a good idea about the compession question you have in regards to octane levels.
 

22crazy

Senior Member
where is the article? if it is the one in articles - detonation it only talks about psi...i need to no the compression of the pistons i need to buy so that it will work with the gas i can supply ( 94 octane )
 

B16

Super Moderator
VIP
i think calesta is running 12.5:1 on 93 octane, that is probably the highest i'd go on pump gas
 

22crazy

Senior Member
ya 12.5:1 is pretty high too...and i no i can get 94 so i dunno i try messaging him and asking him...thanx for the post b16
 

xj0hnx

I wanna be sedated
VIP
Sorry never said it would give you the exact figures your looking for,just a good idea of the theory and from there the world is yours.
 

djextremity

Senior Member
Don't forget, if you're ever out of your comfort zone where 94 octane is NOT available, you will have to be able to run the highest octane rating available with a bottle of octane booster (usually .6-.8 octane) and not get detonation..just something to think about.
 

IMPORT PRO

Junior Member
David

13.0:1 on 100 octane should work, but might nock and ping from predetination but won't harm the motor.

for the 94 octane question yes, 11.0:1 will work even for highway use.

That's coming from a honda/gm technician.
 

posol

RETIRED
Staff member
and you could always retard the dist. if you had to to get by on a tank of weaker gas, and NOT BEAT ON IT or take it up so high...
 
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