Just did a compression test on my cylinders

[differentstrokes]

Just did a compression test on my topend and got 163-165psi per cylinder. This is with vito's superstocks (I know they drop compression some) and 19cc domes. Oh, and the porting. Elevation is around 500-700ft, so all this sounds good since the topend only has around 3 hours. I've ran 110 octane C12 for the break in, but it's around $7.75 /gal locally. I can buy leaded 111 at a gas station for $5.69, and I can also get 100LL av gas for around $4.25 /gal. Just wanting opinions on what is best for my compression without breaking the bank and what mixes together if I can get by doing it. If anybody knows anything about the 100 octane low lead av gas it would be helpful too.

Jared

[differentstrokes]

anybody?

[bansheeseat$$]

Jared,

If the cost of the fuel is killing you either mix the 111 with 92 or lower the compresion on her a bit.I have never ran av gas so I can't help you there.I have to run strait 113 in my 06 but I only race it so I don't go threw it as fast.

[differentstrokes]

I didn't know how the race gas and pump gas mix, seems like I've heard some of them separate or don't mix well. I get 93 at the pump, but I'm wondering what the lowest octane is that I can run SAFELY.

[bansheeseat$$]

don't think mixing or seperating with pump and race fuel is a problem,As for pump and av gas not sure.100 octane with your set up should be fine.I don't see a timming plate advance on your but is your cdi that you got have a differant timing sweep and advance to it?The biggest problem here anyways is the pump gas is never consistant with the labled octane rating.

[RIPPEN]

I have +4 on timing and similar compression to what you got.. I run 91(highest oct at pump here) and I mix it with VP111. Have had absolutly no problem.. If I were you I would mix 50/50 but I would stay away from the AV personaly. Know some that run but know there are some things that arn't good about it.. Ill ask my buddy today if I see what he said was bad about AV gas.

 

RIPPEN

[differentstrokes]

Hey Kai, the cdi is hotter than stock but not extremely aggressive. Rippen, as far as the av gas, it would be really helpful if you could find anything out. I like the idea of the leaded gas if I can help it. But the 100LL is cheap.

[dawarriorman]

I run straight AV gas. As far as the bad things about it, there aren't any, everything that people come up with are just myths. It mixes fine with premix, it isn't "made for high altitudes", it doesn't make the engine run any hotter, it won't change your throttle response. Its gas plain and simple. The reason its so cheap is simply because there is so much more of it used in the country than there is race gas.

 

To me it seems people get put off when they find out how much cheaper it is than racing gas, and they try to find (invent) reasons why race gas is better. And shops that sell race gas want you to buy it from them, not go somewhere else. Of course they will tell you its bad for your motor.

[dajogejr]

There's no way anyone can tell you with 100% certainty what octane you'll need.

 

Personally...with a good advance on the timing, I'd run the leaded race gas...100%.

Mixing pump and race gas gets real old, real fast.

 

Unless you want to take the time to run full race gas, then mix...then backing it down till it detonates...etc.

 

When it comes to octane, compression and timing, I'm on the safe bus.

[Truckracer]

I run straight AV gas. As far as the bad things about it, there aren't any, everything that people come up with are just myths. It mixes fine with premix, it isn't "made for high altitudes", it doesn't make the engine run any hotter, it won't change your throttle response. Its gas plain and simple. The reason its so cheap is simply because there is so much more of it used in the country than there is race gas.

 

To me it seems people get put off when they find out how much cheaper it is than racing gas, and they try to find (invent) reasons why race gas is better. And shops that sell race gas want you to buy it from them, not go somewhere else. Of course they will tell you its bad for your motor.

 

+1 on what he said..

 

For 165 psi I would run straight av gas. 100 octane should be ok.

[wesw]

ran 100LL for 2-3 yrs now never had a problem. just try to keep it fresh like anygas.

 

i paid 3.50 last time i got it if that. hope its not 4 bucks thats steep!!!

 

i say try it you like it, it works 927 40-1 for yrs now

 

best of luck