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The decal on my tank cover from my '01 says to use only 90+ octane. I generally use 91 or 93 octane, whatever the highest octane is available. But the main reason is the low octane and mid-grade octane gas here in MN has around 10% ethanol in it, and some want it to be 20% by 2013. Some stations offer premieum gas for Motorcycles, snowmobiles and collector cars that has no ethanol added. Thats what I like to use.
Interesting point, Pud - Adding Ethanol to gasoline actually serves to effectively INCREASE the octane rating (not that I would recommend it)... Seems counter-intuitive, mebby... :tard::tard:

Wiki explanation: Octane rating - Wikipedia, the free encyclopedia

Earlier in this thread, I stated that the Octane number was inversely proportional to a fuel's power rating... This is only partially true, but it never ceases to amaze me that people ALWAYS associate higher octane with higher power output...

FACT: With all else equal (as long as knocking and/or overheating is not present), lower octane fuel can produce more torque (& calculated horsepower) than higher octane fuel...

I'll assume that some will take exception to the above, and I look forward to the discussions!! :thumbup::thumbup:
 

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Nope, not gonna argue with ya Go, because you are correct. The lowest octane that will allow correct timing advance without preignition (knock) will make the best power.

As you raise the octane # you slow down the burn.

Main issue with ethanol is how it affects seals and leaves residue.. major issue with carbs and jets, not so much with FI.

Of course, for 90% you will have no idea how the engine is doing. Without plug checks and dyno numbers, SOP measurements won't really give you much help.

Also, engine damaging detonation can occur long before you can actually hear "knock", so that isn't an indicator either.

Pulling plugs and using a magnifier and light to look for speckling is the best way. Slight detonation will loosen the carbon deposits and speckle the plug porcelin, so that will tell you there is a problem.
 

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brocks says that and its true but if running high octain can keep the motor safe and allow more timing and run a leaner tune.then there is more power

Past a point lean is not better, nor is more timing. Once you find the point of max torque, advancing or leaning will give no gains. If anything at higher rpm's retarding the timing a bit will give you better MPH numbers.

Now advancing at lower rpms will help driveability, to a point. Just have to be prudent in your approach.
 

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we have a dyno at work(whitch i LOVE) and ive seen a lot of incredable things but runing high octain fuel with a booster can make GREAT HP when tuned write.
operative word is "when tuned right". Just adding octane by itself will not add power.

I've also seen incredibles numbers on a dyno, and then had to re-tune, add fuel and take out timing because it was too lean and to much advanced for real world driving.

The other thing I've found with new models and knock sensors, is if you activate the sensor it pulls a bunch of timing out. So then you crutch it with booster to get it past that point, whereas a finer tune would be better.
 

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operative word is "when tuned right". Just adding octane by itself will not add power.

I've also seen incredibles numbers on a dyno, and then had to re-tune, add fuel and take out timing because it was too lean and to much advanced for real world driving.
thats write but if someone wants it tuned properly with the fuel they run thats what you do we had an LS1 on normal fuel and 12.7 and 22 degress it was close to ping and it made 243 KW at the wheels then he wanted octain booster and good fuel and we got 255 KW at the wheels but it was MAF less all along sorry i forgot to tell you we ran 12.9 and 27 degrees and it still didnt want to ping
 

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my stock LT1 with 7 psi on 93 octane made 450 RWHP, 560 TQ at 11.8 and 32 total advance.

Ran around all the time on the street at 16 psi with no problems, on 93 octane. It's all about the tune.
 

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my stock LT1 with 7 psi on 93 octane made 450 RWHP, 560 TQ at 11.8 and 32 total advance.

Ran around all the time on the street at 16 psi with no problems, on 93 octane. It's all about the tune.
arm is that an LS1 this car im talking about now is turboed and the motor is stock and with a fuel system that is not on it yet but we had it on the dyno and 12 pounds and 12 degrees of timing at 12 to one is point bad ping But it didn't at that set up.one bit more of timing /boost/or AFR/would of killed this motor when the fuel system is on it it should make 500 as a guese at the moment with springs. its a GT 55 garett sorry think GT 42
 

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Discussion Starter · #37 ·
The bottom line is without digging in to the motor to find out what exactly is going on why not just play it safe by using what manufacture recommend or use mid grade (89 which is very close to 90) to avoid engine damage :headscratch: for those of us that commute daily can stick to mid grade or higher so we don't burn holes through our wallets and those that use their bikes for drag/track racing with upgrade engine work should use premium grade :mfclap:

We have invested too much money into our bikes so best to keep things in order......now I feel safer knowing what grade fuel to use, but not happy that fuel prices are way up :banghead: nevertheless, still a lot cheaper than driving my Hemi to work and back :eek:hno:
 

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Also, engine damaging detonation can occur long before you can actually hear "knock", so that isn't an indicator either.

Pulling plugs and using a magnifier and light to look for speckling is the best way. Slight detonation will loosen the carbon deposits and speckle the plug porcelin, so that will tell you there is a problem.
Thats a very important fact right there
 

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The deal was (if I recall correctly) Gadsen and crew did a lot of testing, including tear downs, and came to the conclusion you didn't need anything more than 87 on a stock motor, on the drag strip.

Obviously Kawi chose a "safe" octane number, for the majority of normal riders....

Your results may vary! LOL! :)
 

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The deal was (if I recall correctly) Gadsen and crew did a lot of testing, including tear downs, and came to the conclusion you didn't need anything more than 87 on a stock motor, on the drag strip.

Obviously Kawi chose a "safe" octane number, for the majority of normal riders....

Your results may vary! LOL! :)
:werd:
 
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