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2021 KRX 1000, 2016 Wildcat Sport, 2022 Ram 3500 Mega Cab and 2016 XLR305V12 toy hauler
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Higher octane doesn't equal more power by itself. A engine designed to run on 87 octane will perform as required on it. Higher octane on an engine that does not require it is money out the tail pipe. If you have a tune put into your machine that adds timing, or you added boost to your machine, or you upped the compression you would need higher octane to eliminate detonation. That is all higher octane does... it burns slower and is resistant to preignition.
 

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2021 Kawasaki KRX 1000eS
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Higher octane doesn't equal more power by itself. A engine designed to run on 87 octane will perform as required on it. Higher octane on an engine that does not require it is money out the tail pipe. If you have a tune put into your machine that adds timing, or you added boost to your machine, or you upped the compression you would need higher octane to eliminate detonation. That is all higher octane does... it burns slower and is resistant to preignition.
Amen!
 

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2021 Kawasaki KRX 1000eS
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91 with tune and boost.
 
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The KRX has 11.5 CR which, depending on how efficient the the cylinder head design is (IT'S GOOD), can run on most any octane fuel. But like most modern engines, I think it has a knock sensor that will detect detonation and tell the ECM to retard the timing to protect the engine . That is why you can get away with 87 octane fuel. However, retarding timing results in less power and mileage IN AN ENGINE THAT HAS A HIGH ENOUGH CR TO BENEFIT FROM 91+ OCTANE FUEL.
 

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The KRX has 11.5 CR which, depending on how efficient the the cylinder head design is (IT'S GOOD), can run on most any octane fuel. But like most modern engines, I think it has a knock sensor that will detect detonation and tell the ECM to retard the timing to protect the engine . That is why you can get away with 87 octane fuel. However, retarding timing results in less power and mileage IN AN ENGINE THAT HAS A HIGH ENOUGH CR TO BENEFIT FROM 91+ OCTANE FUEL.
U think wrong.the fuel,timing controls on these machines are very disapointing compared to a modern vehicle.They use a few temp input sensors and old style MAP .That’s why guys that push them hard blow them up!The fuel supply is marginal at best.so becarful hammering the crap out of them.
 

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The KRX has 11.5 CR which, depending on how efficient the the cylinder head design is (IT'S GOOD), can run on most any octane fuel. But like most modern engines, I think it has a knock sensor that will detect detonation and tell the ECM to retard the timing to protect the engine . That is why you can get away with 87 octane fuel. However, retarding timing results in less power and mileage IN AN ENGINE THAT HAS A HIGH ENOUGH CR TO BENEFIT FROM 91+ OCTANE FUEL.
No knock sensor in any of the non-turbo machines that I've saw. I know the Honda and Kawi machines don't. The stock ignition timing in the KRX is very conservative so u can run 87 with 11.5:1. Tune and you really need to run 91-93.
 

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Stock machine and 87 octane is all you need. High octane in a non-modified KRX will actually perform worse, not better, especially if you run at altitude.
Higher octane fuel will not perform worse, it is just a waste of money if not needed. I live in SoCal and Mexico, but do most of my bike riding (CRF 450) and driving (RZR, now a KRX) in Mexico. Everything here in Mexico is powered by Corona, Tecate and tequila! High octane for sure! .
 

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Higher octane fuel will not perform worse, it is just a waste of money if not needed. I live in SoCal and Mexico, but do most of my bike riding (CRF 450) and driving (RZR, now a KRX) in Mexico. Everything here in Mexico is powered by Corona, Tecate and tequila! High octane for sure! .
In my younger years I got involved with white water jet boat racing, down the Balsa River from just outside of Mexico City,to the ocean,then up to Aculpolco.Back then if I Recall all the fuel was from Pemex stations.I would never consider going back to Mexico in today’s enviroment.It was scetchy in both 78 and 85.
 

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In my younger years I got involved with white water jet boat racing, down the Balsa River from just outside of Mexico City,to the ocean,then up to Aculpolco.Back then if I Recall all the fuel was from Pemex stations.I would never consider going back to Mexico in today’s enviroment.It was scetchy in both 78 and 85.
Most PEMEX stations have been replaced by the brands we are used to seeing in the US, but still $1.50 cheaper than SoCal (who isn't?). I have been hanging' around Mexico since I learned to ride in the 60's; we have a second home here. And yes, today's world, Mexico included, is more dangerous. Crazy even! It's safest to stay at home, watch TV with an AR 15 on the left, an 870 on the right, a CZ 75 P01 tucked in your waistband and sleep with a 92F under your pillow. My daughter moved to Mt Eliza, Victoria, AU years ago. She often cites how safe and tranquil it is around the bay. She says (not confirmed) that the homicide rate in the US is 88 times higher than down under. Hum, guess we should all move to AU. Oh, and sell the KRX's, they are dangerous. Point is, I hear you loud and clear, and you are right, crime is high everywhere. It ain't like it used to be! Just be careful, use common sense, shoot straight, and live a full life. (sorry, I didn't mean to sound like a smart ---)
 

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Higher octane fuel will not perform worse, it is just a waste of money if not needed. I live in SoCal and Mexico, but do most of my bike riding (CRF 450) and driving (RZR, now a KRX) in Mexico. Everything here in Mexico is powered by Corona, Tecate and tequila! High octane for sure! .
Actually it will not run as well with high octane at high altitudes due to the fact that it will burn slower. Don't know if you would feel it with the butt dyno, but it is a fact. Regardless, high octane in a stock motor built to run lower octane fuels is a waste of $$.
 

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Respectfully disagree Bob. They burn at the same rate (flame front speed) but higher octane fuel resists detonation (an explosion instead of a burn) better. Keep in mind that detonation and pre ignition are separate occurrences, detonation being the most destructive. I have torn down numerous bike engines with piston damage caused by detonation. Detonation damage is very distinctive (usually piston damage around the edge of the crown of in valve reliefs pockets). This is not my conclusion alone, it is backed by some very well respected engine builders who clearly understood cylinder head design and flame propagation (laminar and turbulent), AKA C.R. Axtell and Rob Muzzy, both operating out of SoCal, near my home, at the time.
 
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