So if I'm running 104 unleaded, in order to get the most out of my 100 shot, could I advcance a degree or two of timing? Or should I leave it where its at? On 91 my timing strap was right where it needed to be on the plug, but when I use 104 will the timing mark move? Or stay the same?

 

If your car is tune optimal for 91 you will need to add timing or nitrous to take advantage of the higher octane. Do you have pics of your plugs from your 100 tune up?

 

 

Higher octain = slower burn/resistance to detonation .... so, yes (agree with above)

 

Leave timing alone.

Make a hit, check plugs on current tune.

Judge plugs and tune-up once you have done this.

I am not really a fan of jacking up the timing.

I like to either add boost, add nitrous or lean out the mixture.

 

I agree.

If you have the timing correct for 91 octane, you probably won't see
much improvement anyway.

 

If there is room for it for all-out power, I say advance it a degree or two. As long as KR is at bay and plugs warrant it, sure!

 

If he is on a 100 shot he is barely spraying anything!

No point in advancing timing when he can just add nitrous! Motor wants the least amount of timing it can use to still make peak power!

Not saying any ONE way is right or wrong, but just that there are better ways to make more power while keeping your tune-up clean and safe.

 

I don't have any picture of my plugs. I'll do a pull with some new plugs then post them up soon. Should I pull all the plugs and check them? I've just been going of cylinder 5 and 7.

 

Oh and also thank you for all the great info!

 

^^^This is not good advice. If you looking at a device to see knock while spraying its too late, motor is hurt or gone. You read your plugs, they will tell you of any issues before any device will tell you if you have knock retard.

 

When I am making changes to a tune up I pull all 8.

When I am verifying tune is still in line with what I like to see after I have used the new tune up several times and I am getting comfortable with it I pull from each corner like this: 1,2,7 and 8.