what amount of boost is optimum with pumpgas on 8.25:1 cr BB?
 

blower users,can you pls give me some idea:
what amount of boost do you put on top of 8,25:1 cr ,540 cu in engine.short deck.pump gas.

note comp ratio is 8.25:1(edited)
thnx

timucin,

What kind of octane do you get over there ?(US conversion ?)

You have a fairly conservative CR(Good)

Are you looking for a max boost ? I would say conservatively #4-5. High end (with all good internals) #7-8.

With EFI and good intercooling don't be afraid of 12-15 lbs boost! Just avoid detonation and have good meters-A/F, o2, EGT.

;)

thnx all
I think pump octane is around :90

higher octane will allow you to run more boost

hotbeek,
that’s obvious, but just how much more?

say one is running 8 lb. of boost on the edge of detonation with 90 octane, if he switches to 93 octane exactly just how much more boost can be run?

I heard about a serious 'powder' octane booster.they say very small amount of it gives +10 more octane
is this true?
what is the name of this product?
who produces it?
where can I buy?

10% Tolulene will increase octane by 2-3points.

dean,

sorry I don't have an exact answer. It's a little "voodoo" science. Too many variables to narrow it perfectly. Cobra has the right idea with the meters. If you can swing these it will tell you what's going on inside. A/F,O2,EGT. If you have access to a competent dyno that would really help dial things in. I for one do not like to feather things out to the edge. I always like to fail to the safe side.

timucin,

here's a product that claims 16pts ?!

http://www.kemcooil.com/fueladditives.html

I've never used it , just going by the advertisement. I'm always a little leary on these miracle cures ?!