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11:1 Comp. on Pump Gas?

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I have a 2013 TRX400X and I'm planning to put a 11:1 high compression piston in it pared with a stage 2 Hot Cam to get into ATVMX and I'm wondering if I could get away with running 93 octane ethanol-free gas in it. 

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On 7/17/2020 at 12:48 PM, duCOD pro said:

I have a 2013 TRX400X and I'm planning to put a 11:1 high compression piston in it pared with a stage 2 Hot Cam to get into ATVMX and I'm wondering if I could get away with running 93 octane ethanol-free gas in it. 

Quite likely. Modern MX bikes are well over 12:1.

 

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On 7/16/2020 at 10:48 PM, duCOD pro said:

I have a 2013 TRX400X and I'm planning to put a 11:1 high compression piston in it pared with a stage 2 Hot Cam to get into ATVMX and I'm wondering if I could get away with running 93 octane ethanol-free gas in it. 

This is ABSOLUTELY NOT a question to be guessing at or asking anyone who does not know the exact answer or how to get to it. No offense to Momus or anyone else who may post but this is life or death for your engine if you get it wrong just know that going in. Whoever it will be that you buy the piston from will / should be able to tell you everything you need to know about minimum octane rating. If they can't buy your piston elsewhere. If you don't know for sure what minimum octane rating to use just call Wiseco, tell them what you have, what you are going to do and they can tell you what fuel to run so your engine is safe. To go one step further you want to race the quad, this will be your first lesson on how everything needs to be just right before you go wild. 

Here is an example  piston diameter or  bore size alone is just one factor in determining what fuel you can run. A small bore XR80 can probably run 13.5:1 on E free 93 or whatever the highest you can get where you live. Head design 2V / 4V, piston design, cams, rod length ( piston dwell time ), stroke all factor into this equation.

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2 hours ago, BrianPaul69 said:

This is ABSOLUTELY NOT a question to be guessing at or asking anyone who does not know the exact answer or how to get to it. No offense to Momus or anyone else who may post but this is life or death for your engine if you get it wrong just know that going in. Whoever it will be that you buy the piston from will / should be able to tell you everything you need to know about minimum octane rating. If they can't buy your piston elsewhere. If you don't know for sure what minimum octane rating to use just call Wiseco, tell them what you have, what you are going to do and they can tell you what fuel to run so your engine is safe. To go one step further you want to race the quad, this will be your first lesson on how everything needs to be just right before you go wild. 

Here is an example  piston diameter or  bore size alone is just one factor in determining what fuel you can run. A small bore XR80 can probably run 13.5:1 on E free 93 or whatever the highest you can get where you live. Head design 2V / 4V, piston design, cams, rod length ( piston dwell time ), stroke all factor into this equation.

I run the Australian equivalent of 93 on 14:1 engines with compact, flat 2 valve chambers.

11:1 will be fine; it is a moderate ratio.  Wiseco have already given their opinion by manufacturing and selling the piston and not mandating 'race gas'.

.

If any concern retard the timing and check jetting.

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On 8/1/2020 at 7:52 AM, Momus said:

I run the Australian equivalent of 93 on 14:1 engines with compact, flat 2 valve chambers.

11:1 will be fine; it is a moderate ratio.  Wiseco have already given their opinion by manufacturing and selling the piston and not mandating 'race gas'.

.

If any concern retard the timing and check jetting.

Alright, I have some fast trails close to me that I ride so by the sound of things I will probably run 93 octane ethanol free gas on the daily and race gas for racing on MX tracks

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There are two compression ratio values. Static, which is the number a piston supplier provides, it assumes the deck height and combustion chamber is unchanged. Dynamic is with cams and the head design taken into account. Depending on intake velocity, duration, lift, quality of ports, this number can be higher or lower than static.

If a machine runs fine on pump premium, there is no reason except to spend money on fancy fuels. 99.9% of the time, a static ratio of 11:1 does not even need premium, mid grade is fine. The lower the octane, the greater the power. Octane is just a resistant to detonation and pre-ignition (uncontrolled burning),.

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On 8/1/2020 at 1:43 AM, Momus said:

Quite likely. Modern MX bikes are well over 12:1.

 

What class you planning on running down there in a Texas? I doubt anything you do to a 400EX will result in the ability to run w/ 450cc machines.

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