Pepe's Latest Beverage

[xschop]

Was able to take the xs out today and decided to fill up at the Nichols Hills Shell station since he was very low. I usually don't get my gas there, but filled up only two gallons of 101 octane ($5.49/gallon) to see what all the hoopla is....I definitely felt it in the seat after a few blocks, so I took him out to the Oklahoma Autobahn (I-35) and pegged her all the way to the 140 mark on the speedo with this 750 final drive.....I'm impressed, but I won't be doing that again...87 octane at 7-11 ($2.89) will get me as fast as I need to go......Was fun though

[mason79]

wow, that's news

[Snow]

I think about the only thing racing gas will do for a stockish XS11 is to clean up the valves/combustion chamber if run WOT a few times - which certainly does help!

[Brian_D]

premium = better mileage

before the gas hike a few years ago, I noticed premium gas would not only provide the seat 'o pants response but provide some extra miles between fuel stops.

now I'm so frugal I've begun using the 10% ethanol blend

[xschop]

higher octane

If I wasn't afraid of fragging my newly refurbed clutch, I think I could get a first gear wheelie.The power is that much pronounced with this stuff in the tank (about gone now).I'm not the petrol expert, but I wonder what the Dyno would look like between 87 octane and 101....Also I have access to top grade ethanol and as I have read here and other media, adding ethanol lowers mpg's...respectively, but does adding etoh increase horses or dull them down?

[Snow]

I hate to break it to you folks, but if the bike runs without detonation on 87 octane and you do no modifications/adjustments, you will not see a performance gain either in mpg or hp/tq.

The reason many flex-fuel vehicles get worse mileage on E-85 is that they are tuned more for gasoline, meaning lower compression, less ignition advance, and/or other variables.

The higher the octane rating of fuel, the slower it is to ignite, thus the reason higher octane is preferable in high performance engines that would otherwise get detonation with lower octane fuel. The downside to higher octane is that if your engine is set to run 87 and you run 93 (or higher, just an example), it takes longer to burn and your ignition is not advanced enough to completely and thoroughly burn the fuel. Like I mentioned earlier, the race gas isn't doing a thing for your bike directly, but it probably is helping to clean up your combustion chambers, which in effect, gets the bike running correctly again - once the chambers are all clean, your bike will run as well on regular gas.

And finally, a BIG WARNING - if your bike is stock, in particular the carb jetting, do NOT run E-85, ethanol, and DEFINATELY do NOT run methanol. You will probably end up melting a piston as ethanol, E-85, and methanol have different stoichiometric ratios than gas. You must increase your jet size by around 30% to have correct stoich foe ethanol/e85 else you will be running *very* lean.

I've done quite a bit of research into E-85/ethanol as I'm working on converting my car to flex fuel using a megasquirt ECU (MS II supports flex fuel) - of course I'm still learning a few new things every once in awhile. If you have any questions about this stuff, I'd be happy to share if I know the answer.

[DiverRay]

Snow,
I hope you plan on replacing ALL the fittings, seals, and hoses in your car! E85 is VERY CORROSIVE, and you need the proper type of hoses and seals to keep from leaking fuel everyplace.
I WOULD NOT convert to E85, as I DO NOT live in the middle of the country, and don't have cheap access to the fuel. The State of California bought a fleet of vehicles to run on e85, and it has cost them more money and pollution than if they just bought regular vehicles. The Govenator does NOT understand the economics of being green. Around here, biodiesel is a better solution. It can be produced locally, and in almost any quantity WITHOUT the hazards and pollution of E85.

[Dsxs11]

The price of regular gas at the only E-85 station in Metro Detroit was 2.95 a gallon the price of e-85 was 2.75 a gallon. My flex fuel Taurus gets 19-25 on gas and 13-19 on E-85 advertised. I can get about 27 on fuel and 18 on E-85 so it's pretty much a non issue. I'll pay the .20 gallon difference and get the other 6 mpg.

[Snow]

Ray,
Yes, I plan on replacing my entire fuel system from tank to rails - need to research injectors. Alcohol is incredibly harsh on raw aluminum and of course, my tank is aluminum :/

I think I might just try to get the inside of the tank coated or anodized. You got me thinking though, I should keep a journal of everything I do with this project...

We have one E-85 fuel station in Tallahassee and no others for a couple hundred miles, so that's why I'm going flex-fuel rather than E-85 only. One reason I'm converting is for performance and the other is I'd rather keep most of my fuel dollars in the US rather than funding terrorism.

[trbig]

I see people all the time telling others (And me) that running higher octane does nothing... but when I put it in and there's a noticeable enough difference for me to actually feel on acceleration from one to the other, I just have to cal Bull S%$*

Sorry... I can feel it in my car, and I felt it the one time recently when Hobbyman and I were riding hard when we filled with some 93 octane. Since I always just run the 87 octane and I do take this bike through it's paces probably more than the average rider, I know how it feels from one to the other. After that tank when I went back to the 87... I could feel that, so it wasn't just the valves being cleaner. I never have noticed much of a difference on fuel mileage, but my riding varies so much from day to day that it would be pretty hard to determine except for long trips. Hmmm... how many times today did I twist that throttle WFO??? lol. Plus, the XJ's are all electronic on the timing and ignition...

As we speak, I have 2 1/2 gallons of 108 octane sitting in a can waiting for me to finish the tankfull of 87 I am on. I'll let you know.

Tod

[oseaghdha]

Plus, the XJ's are all electronic on the timing and ignition...

Tod
Does it have a knock sensor?
That may explain the increased performance.

Ethanol has less energy per gallon in it. Thats why you get crappy mileage.
Racers use it because you can run ridiculous compression ratios with it, which means you can cram even more fuel/air into each stroke.
Nitro methane, on the other hand, releases oxygen when it burns so you can use even more of that.
I think I read that a top fueler will burn upwards of 15 gallons in quarter mile.

[webbcraft2150]

I notice a difference between 87 and 91+ octane in my XS. I use the higher octane stuff consistently. Not that big a difference when you buy 3-4 gallons at a time.

An interesting note. When I was wrenching on boat motors and Merc came out with the supercharged Verados, Merc said to use 91 or better fuel. You could run lower grade fuel, but the engine would not develope the rated horsepower. I actually saw them run back to back, a Verado, on the dyno, one with 91 and one with 87, the run with 87 showed 'bout a 31 hp loss at the prop. The "puter did the figuring and backed off timing and injector duration and fuel pressure. If you can afford a Verado powered boat, you should be able to afford the right gas to run in it.

[trbig]

If you can afford a Verado powered boat, you should be able to afford the right gas

We were on our way home from Kat and John's house last night when the Mercedes we were pacing got nailed topping a hill at about 90. As we went by (Slowing down considerably) my wife said, "Oh well.. at least they can afford the ticket!" I said, "Maybe not... mighta spent all their money on the stupid car!"

Maybe the case with that Verado?? lol

Oseaghdha... no idea about a knock sensor, but I doubt it. I'm no genius by far, but I'm not understanding why you'd have to advance timing for a little more octane? In the 87 octane, it igintes to drive the piston down, but finishes exploding long before it reaches the bottom of the stroke. The rest of the travel is just piston rings dragging on cylinder wall. The higher octane just let's the explosion last a little longer so there's not quite as much drag at the bottom. It's not like it's still burning so slow it has fire coming out your pipes. It shouldn't need to explode sooner... it's just lasting a little longer.

Tod

[oseaghdha]

I am not saying you have to advance the timing, just that you could. High compression and large advance = lots of power.
If you bust it off before TDC, you get a lot more pressure. The more before TDC the bigger the bang (up to a point). Its like tamping an explosive charge.
I didn't know if the computer control on the XJ included a sensor which would allow more timing. I know some auto makers were messing with that in the early 80's. I am ignert about XJs.

When I run race gas in my 400 Firebird, I kick the initial up to 18 BTDC, with 36 total.
On pump gas the best I can do is about 12 before it starts pinging. That's with 10.75:1 heads.

I run premium, because that's what the label on the bike says.

[Crazcnuk]

"I see people all the time telling others (And me) that running higher octane does nothing... but when I put it in and there's a noticeable enough difference for me to actually feel on acceleration from one to the other, I just have to cal Bull S%$* "

Psychology is a wonderful thing. Too bad, though, if you make no other changes your bike is going slower on high octane.

Chemistry is chemistry and math is math. It's like all those idiots that pull thier mufflers off and FEEL the extra power ROFL.

If you put a few more degrees tiiming in, you may feel a little extra punch.

BTW the 500+hp 502 mentioned below calls for premium fuel, but after considerable testing, at the track, I run regular in it. It goes faster and is a lot cheaper. Of course we are talking hundredths, but the savings are considerable.