holyshift

Thanks guys,Ill let you know what happens,also dont have o2 sensors,but anyways,Ill let ya know.

mjr46

true but the whole point of running race gas is to reduce the possiblity of detonation, the higher the octane the slower the burn rate, yes on a N/A motor with such compression, I'd say 93 is sufficient, heck that's what I ran last weekend, however, when running boost or in the OP'S case N02 where cylinder pressures will be greatly elevated to where detonation could possible occur, I like to error on the safe side 100-104 IMO would be fine, expecially if you drive to the track on a tank that already has 93 in it cause when the higher octane mixes with the regular gas, lets say you use 104 then when it mixes with 93, you'll most likely be in the middle somewhere

JD1969

Bah, I never worried about running anything more than 93 on a little 100 shot, but you are right to err on the safe side.

67mustang302

You can actually run into issues with too high of an octane, even when on the bottle. Here's an interesting article from Pro Systems on that. http://www.prosystemsracing.com/scoop040909.html And keep in mind that if you start to get backfiring from too high of an octane....on nitrous...you can get exhaust issues. Worst case scenario you could get an effective lean missfire from too high an octane and then on the next intake stroke you possibly could end up with an intake backfire on nitrous. Bad news.

I run 91 in mine with 9.44:1, but it's also California fuel which is highly oxygenated and has tons of additives, but I also run a lean fuel mix with aggressive timing in an area where summer temps can sometimes exceed 110 F.

With nitrous you may be better off running on the rich side with the shot than running higher octane, depending on fuel availability. A mix of pump and 100 would be ok for a small shot, but I'd be wary of running even a 110/pump mix with a small shot. And even if you don't get backfiring, if you end up with fuel burning in the exhaust system it can be bad for O2 sensors due to the excessive heat they'll see, and they can get sooted up.

Derf00

Don't know if it matters for the ops particular case but doesn't 110 Octane also contain lead?

67mustang302

Some of them do, yeah. 110 octane is not 110 octane. Some have lead, some don't, and depending on what was used in the blending, different suppliers can have completely different jetting and timing requirements. And of course if they have lead and the jetting is wrong you can also get lead fouling of the plugs as well.

Part of the problem the op has may also be specific gravity of the fuel. Many race fuels have varying specific gravities for the same octane, so using 110 octane from a different supplier with a different specific gravity can throw the afr all out of whack.

88GTBLACK

i run 110 cam2 in my power washer and my leaf blower at my shop drained from my bosses 1000hp supra. Works great! why would you run race gas?? are you racing? i dont mean to put you on the spot or anything but i agree with everyone else it wont burn youll foul out plugs and leave crap in cylinders.

holyshift

Ok again I dont have o2 ssnsors,but thanks for all the info,and yes I race this car almost every weekend,well until this happend.Just thought I was doing the right thing by running the 110 cam 2,but obviously not.Still havent got to work on it yet I will post as soon as I try something.

holyshift

Pulled the carb and cleaned it all up,found a piece of something in one of the jets,thought that was the problem but nope.Gonna drain fuel tomorrow and put pump gas in it.Its such the slightest break up at all rpm's.My buddy thought I was on crack but once he went for a ride he heard it.Could a bad ignition box be a culprit?Iam running the summit racing box which is Mallory components,any thoughts?Also with the motor breaking in would that cause anything to act up?

67mustang302

Check plugs, wires, cap and rotor first. Ignition boxes rarely fail.