Compression and Octane Rating?

[tdub400ex08]

I recently posted about getting a 460 stroker kit from trinity racing in an 11:1 compression ratio which I was told by the tech would be closer to 11.5:1 because of the stroke of the crank.

I asked about running on premium and he said “no with 91 you would need to mix in a little race gas or add some octane booster” I said “in Indiana we have 93 every where” and he said “yes that would be fine”.

What do you think? Most post I have read say 11:1 is about as far as you want to go. I will have an aftermarket external oil cooler. Trinity also said that because of the thicker sleeve that they use in the kit it helps keep temps down.

Can I just use 4oz of Klotz octane booster per tank or will I be fine?

Do I need to just look for a different Kit if I want to run on Premium?

Whatever I do I want to stay away from races gas as everyone I ride with can at least run on 93 and I don’t want to get stuck on a trip somewhere unable to run because I have no gas.


Thank you so much for your help!

[Muzzgit]

Cheap.
Fast.
Reliable.

Pick any 2.

At the end of the day, this is your number one consideration.

If you want it to be reliable, don't go with such high compression. A 460 with a few mods will have more than enough power. If you need more, you have the wrong quad.

[VTredneckgames]

and octane boosters do nothing

[F-16Guy]

Mix 50/50 E85 and bump the jetting up a little. You could also run 50/50 with 100LL AVGAS, which can usually be purchased at your local munipal airport for relatively cheap. I've run 50/50 100LL in my 416 at the dunes several times with zero problems.

[bigbad400]

octane booster will help mine if i can only get 91, i use klots and walmart brand and they both stopped the missing and like from the cheap gas. i have 11:1 and 93 is fine im sure you will be fine with 93. i think if you got that kit you should be fine to run on premium. with the oil cooler you should have no prob keeping it cool. all i have is a spal fan and its fine.

[TRXRacer1]

Originally posted by tdub400ex08
I recently posted about getting a 460 stroker kit from trinity racing in an 11:1 compression ratio which I was told by the tech would be closer to 11.5:1 because of the stroke of the crank.

I asked about running on premium and he said “no with 91 you would need to mix in a little race gas or add some octane booster” I said “in Indiana we have 93 every where” and he said “yes that would be fine”.

What do you think? Most post I have read say 11:1 is about as far as you want to go. I will have an aftermarket external oil cooler. Trinity also said that because of the thicker sleeve that they use in the kit it helps keep temps down.

Can I just use 4oz of Klotz octane booster per tank or will I be fine?

Do I need to just look for a different Kit if I want to run on Premium?

Whatever I do I want to stay away from races gas as everyone I ride with can at least run on 93 and I don’t want to get stuck on a trip somewhere unable to run because I have no gas.


Thank you so much for your help! It's not as simple of a question as what compression. Compression is just a contributor to the source of detonation. Heat is the culprit and things like compression, bore size, timing advance and of course cooling all play a role. I'm more of a deep woods rider that tends to push hard for long periods of time. I'd make a stock bore 11:1 ping 93 octane.

You're talking about a 460 at 11.5:1! I find it completely irresponsible of Trinity to recommend pump gas on a build like this in an air cooled engine. If you're in wide open air cruising down trails you should be fine but that's because you're keeping engine temps down. If you're burning it up on some technical riding you'll need more octane.

Stay away from boosters. F-16Guy had a great post to follow on fuels but if that's just not going to work for you should kick that comp down into the 10's or retard the timing a little. Either way will work and both will be easier on your crank assembly.