RE: Octane, Compression Ratio, and Detonation.
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RE: Octane, Compression Ratio, and Detonation. - 9/20/2006 5:56:07 PM
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zerochickenstrips
Posts: 513
Joined: 7/31/2006
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I've been running 87 octane in my '06 1KRR for about two tanks with absolutely no new noises or decreases in performance. I, like many others in this forum, have been trying to spread education to folks who believe that super is better including a link to a website that explains it and includes a dyno sheet showing that lower octane made better, more even power on their particular bike, but no one listens and instead decides to argue because surely they must know better. I'm thinking about doing a couple of dyno runs when I get up some money and compare 87 octane, 93 octane, and race gas (maybe 98 octane?) To get a difinitive answer for all the neysayers out there. I hate it when they ney-say...they're always ney-saying 
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'06 Black CBR 1000RR
'91 CBR 600 F2 streetfighter
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RE: Octane, Compression Ratio, and Detonation. - 9/24/2006 5:10:26 PM
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Ocelaris
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I don't have any evidence that bikes are tuned differently in different countries. But I just came back from the UK where their minimum octane is 95, and goes up to 103 I believe? Now it may be just a different method of calculation. But there are variations of different motors, at least as far as Honda K-series are concerned that require the higher octane that I am under the impression, US soil does not permit. i.e. K20a2 versus K20a which is only a ~20bhp difference, which can be attributed to .5 more compression and advanced timing in the ECU. If someone knows differently, please speak up, but the circumstantial evidence suggests that there are different honda motors for different lands...
I am under the impression/belief at this point that US fuel is lower octane, hence they can not handle some of the higher andvanced timings that some motors are tuned for. I could very well be wrong, but haven't heard definitive proof either way at this point.
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RE: Octane, Compression Ratio, and Detonation. - 9/24/2006 8:50:48 PM
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chainstretcher
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Just advancing the timing with no engine modifications won't really net you anything except marginal power gains and a lot of extra heat and wear on the engine. I don't know what a K20a2 or K20a is exactly -- is it a bike engine? Bumping the compression .5 doesn't seem like 20hp but I guess it could be done.
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It's better to burn out ...
Than high side!
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RE: Octane, Compression Ratio, and Detonation. - 9/25/2006 6:21:54 AM
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DrDRFT
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quote:
ORIGINAL: Ocelaris
the K-series motors, k20a2 k20a3 k20a etc... are the newest Honda 4 cylinder auto motor series... the JDM motor is the K20a with slightly higher compression (not sure exactly off the top of my head the exact #s), cam profiles etc... some other things... they're ~20bhp more powerful, but also I assume advanced for higher octane gas.
that answers my question, advancing the timing for higher octane won't do much.
But if that was the case then why do people run advance timing and run race fuel? if it didn't make more power they are better of running cheaper fuel?I too thought that maybe in Australia we are running a different map(more advanced) due to our lowest fuel being 92octane. And our highest octane fuel from the pump is 100octane... in our Honda manual it states that we should use a minimum octane rating of 95! Now if the US and Australian bike are exactly the same why do we have to run different octane??? I don't know this is why I am asking on this site as it seems there are alot of people in the know here! Only way to learn is to speculate then ask peps in the know!!! my $0.02.....
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RE: Octane, Compression Ratio, and Detonation. - 9/25/2006 8:12:20 AM
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chainstretcher
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Generally when you raise compression significantly you tend to take out timing -- not add it in. Otherwise you get detonation. As for race cars ... NASCAR runs 12:1 in a 358 ci V8 -- adding in timing would grenade that bad boy.
I don't know for a fact that Honda isn't running different maps for different countries. The extra compression in a car motor would account for the 20hp -- timing may or may not be another factor.
In the states we use the R+M/2 formula for calculating octane at the pump. How about some of you guys across the pond find out and post how it's measured in your yard. Different formulas for calculating the octane would be a simple enough explanation on why they require higher octane in Oz.
_____________________________
It's better to burn out ...
Than high side!
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RE: Octane, Compression Ratio, and Detonation. - 9/28/2006 4:14:39 AM
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Pugetpower
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Some of these posts when over my head but from Slipper's original, I learned I have to increase my Omega 3 fatty acids. Kidding aside, I went to "regular" (washington state gas) from my 3rd tank on and havnt found a reason to go back, not even to the "mid" grade. ps Im a street rider only.
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RE: Octane, Compression Ratio, and Detonation. - 10/10/2006 1:21:52 AM
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HondaCBR600RRhunk
Posts: 79
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Good thread guys. Just a heads up though. I have a 2004 CBR 600RR and in the manual it states 86 octane or higher is the recommended for this bike. With that said if you look in the owner's manual, we should be changing gears every 7miles our so until we get into 6th gear, so basically about 30miles an hour or so in 6th gear is recommended. With that kind of riding, yeah I guess 86 or higher octane is perfect for that application. But who the hell rides like that? If your riding hard like the average joe, than a higher octane gas is recommended in my opinion. Another heads up for you guys and gals. The other day I looked under my back seat, and noticed a sticker with info for my bike. You know info like spark gap size, tire info, and oh yeah octane recommendation. CHECK THIS OUT.... Honda recommends 91 octane for my bike afterall. No sh*t. Check your sticker and let me know if yours has the same thing. I bought my bike in Canada, but that shouldn't make a difference. Ever since I noticed the sticker, I've switched to 91 octane. Bike runs the same as it was with 87 octane to tell you the truth. But I just wanted to go with what the sticker seat said. I just picked the higher number, to make sure because in 2nd gear I'm doing over a hundred, so I just don't feel right using 87. Why would there be a discreptancy from what is stated in the manual and what is stated under the back seat on a sticker? Okay guys you know the drill, go to your back seat and read the sticker, do you see 91 on there? Let me know, and let the forum know this as well. I'd hate to see someone screw up there bike, because they were running 87 when really we should be riding 91 minimum. Just my 2 canadian cents. And no I'm not trying to argue or go against other opinions on here, just reading you the facts, thats all.
< Message edited by HondaCBR600RRhunk -- 10/10/2006 1:25:00 AM >
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RE: Octane, Compression Ratio, and Detonation. - 10/10/2006 1:52:25 AM
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abadfish
Posts: 771
Joined: 6/26/2005
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quote:
ORIGINAL: HondaCBR600RRhunk
Good thread guys. Just a heads up though. I have a 2004 CBR 600RR and in the manual it states 86 octane or higher is the recommended for this bike. With that said if you look in the owner's manual, we should be changing gears every 7miles our so until we get into 6th gear, so basically about 30miles an hour or so in 6th gear is recommended. With that kind of riding, yeah I guess 86 or higher octane is perfect for that application. But who the hell rides like that? If your riding hard like the average joe, than a higher octane gas is recommended in my opinion. Another heads up for you guys and gals. The other day I looked under my back seat, and noticed a sticker with info for my bike. You know info like spark gap size, tire info, and oh yeah octane recommendation. CHECK THIS OUT.... Honda recommends 91 octane for my bike afterall. No sh*t. Check your sticker and let me know if yours has the same thing. I bought my bike in Canada, but that shouldn't make a difference. Ever since I noticed the sticker, I've switched to 91 octane. Bike runs the same as it was with 87 octane to tell you the truth. But I just wanted to go with what the sticker seat said. I just picked the higher number, to make sure because in 2nd gear I'm doing over a hundred, so I just don't feel right using 87. Why would there be a discreptancy from what is stated in the manual and what is stated under the back seat on a sticker? Okay guys you know the drill, go to your back seat and read the sticker, do you see 91 on there? Let me know, and let the forum know this as well. I'd hate to see someone screw up there bike, because they were running 87 when really we should be riding 91 minimum. Just my 2 canadian cents. And no I'm not trying to argue or go against other opinions on here, just reading you the facts, thats all.
Your "facts" are wrong. You are misinterpreting the sticker on your bike. The sticker and the manual are actually saying the same thing. Read this (I just don't feel like re-typing it)
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RE: Octane, Compression Ratio, and Detonation. - 10/10/2006 10:18:03 AM
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HondaCBR600RRhunk
Posts: 79
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I read it again and the numbers don't change by starring at it, believe me. The manual says 86 or higher octane and the sticker under the seat says 91. Anybody else read the same thing, post on here.
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RE: Octane, Compression Ratio, and Detonation. - 10/10/2006 11:30:35 AM
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Tahoe SC
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well...if you take what abad's thread says and apply it to the numbers...makes perfect sense...but alas, use what you want to make your heart feel good and your head good!
i now only use super duper thug gansta mawfaki octane gasoline that can only be found in the hoods of LA...it's rated like 1000 octane or something...and it really does make my bike go faster!!! why? cause everytime i gas up with this stuff, i get mugged, so in addition to the price of gansta octane gas...which is bling...and the amount of money they take from me...my wallet is so light that just the weight savings alone made my bike go faster! i have tried the same thing at other places, but the thugs there don't take just the right amount of money so power suffers.
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