compression ratio

[spud400ex]

what is the highest compression ratio i can run with pump gas? i will be using 93 octane if i go to an over bore.

10.8:1 definitly will run on 93 with no issues...:D

Some say 11:1 will work and some say no,,I"m willing to say it's the border line compression to run with 93. I went with the JE 10.8:1 compression and it will not ping at all on 93 and for some added pull from bottem to top put some 110 or a mix of 110/93 in that badboy and it runs even better..:devil

[quadrcr87]

i put a 12:1 in my 250x. its making a sound like its the valves or something? is that the kind om pinging sound it makes?

I"m not real familear with 250x's but I'd say it's highly possible..

[quadrcr87]

how would you descibe the pinging caused by compression. is it really noticable

[Big - D Racing]

Honda recomenneds running 92 octane or higher with the stock compression. That's what you should be running now, not 87. If you are you can be hurting your engine.

[RED121572]

11:1 is the limit for pump gas. I run 94 in my Honda and it does fine.

[KandK952]

on a 426 with 12.5:1 it is ok to use 94 or higher. so i dont think 11 is the line.

[thelegendarycd]

i'd say 11:1 probably would be safe. i've heard of people running the 12:1 in 250x's and thats what i'll be doing but i'll have to run 93 or 94.....if it pings like quadrcr87 said i might have to run a mix with race gas. but 11 should be ok for you.