Alright so im about to be tunning imburnes and my vitara setups for hoping around 20psi on pump gas 91 octane if possible? So what im asking is... To achieve this how do i know when race fuel (something over 91 octane) is a must?? I mean with just street tunning...?? I can keep the timming really really conservative and keep the afr's at low 12s to high 11s.. But how do i know when i need to take it up a notch and pump gas is not gonna work even if im not hearing detonation i dont want to get it to that point.

 

You have to read your torque curve. and check your sparkplugs for detonation. Not all detonation is audible.!

 

thanks bro! But how would i read my torque curve if im not on a dyno?? I want to do a good street tune for pump gas before we get it on a dyno and try bumping up the boost more for race gas. What would i look for with the plugs??

 

You look for signs of detonation on the plugs. usualy you can see realy smal aluminum grains on the electrode. kind of like sandish deposits.

 

you need to search plug reading on here or google... or post a picture of your plugs

 

Yeah, I put out a nice little thread on plug reading in this section a few months ago, has all kinds of little details on how to read them down to finding if you have extremely light detonation to even if you're running too much timing with no detonation, and how to roughly read AFR's off plugs in a pinch and whether or not your plugs are too hot/cold.

Shame it wasn't made a sticky, it had alot of necessary info on the dark art of plug reading.

 

http://www.dragstuff.com/techarticle...ead-plugs.html

http://www.dragstuff.com/techarticle...ark-plugs.html

 

Simple answer your boosting 20 psi+ race gas. I know I know you saw on the internet blah blah blah. Race gas is nice it allows huge errors in tuning. Play it safe and Im sure your not going to be running 20 psi on the streets no point. 25 degrees race gas lots of boost things dont break. Pump gas no timing in the motor things break.

 

good info bro! Im gonna have to read all that when i get off work lol!

 

true true true! Thanks for the info bro.