i have a well built ls/vtec with CTR pistons on Hondata and many other upgrades. I am about to sell the car and i wanted to see how fast it would be on racing fuel. What would be the best octane to use and would it have to be tuned again?? Or could i just dump it in there and have it run right?? i think the compression is about 12.3. I saw a ad for 105, 110, & 120 all about 6.50 to 7 dollars a gallon isw that about right??

 

put in some 105 and advance the base timing about 2-3 degrees.

 

My 13.3:1 comp LS/VTEC runs fine on 100 octane, no need to buy higher w/ your compression. I pay $4.80 a gallon for 100 too.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 85mm LS VTEC &raquo;</TD></TR><TR><TD CLASS="quote">My 13.3:1 comp LS/VTEC runs fine on 100 octane, no need to buy higher w/ your compression. I pay $4.80 a gallon for 100 too.</TD></TR></TABLE>

My 12.7:1 compression runs fine on 93 octane..

but to answer your question
If you run a higher octane, to see any real noticable difference yes you will need to adjust some stuff in the tuning