Hypothetically speaking, how would 100LL fuel run in a newer, fuel-injected motorcycle?
100LL In Bike
- Thread starter V1
- Start date
- Status
Isn't that too much octane?
it's ok but avgas is really not formulated to be run in ground vehicles. aircraft engines run at constant speeds in cool air for hours. it is also made to not boil at higher altitudes among other things. that is the opposite of a bike engine.
you'd be better off blending high quality leaded race gas in with premium pump gas.
you'd be better off blending high quality leaded race gas in with premium pump gas.
Thanks, Tom! Help me understand this a little bit better: You believe it works alright, but it's not as beneficial auto race fuel? I'll buy that.
Is there any benefit to running an occasional tankful?
Is there any benefit to running an occasional tankful?
Many of the new FI bikes use a a catalyst in the exhaust, which wouldn't like the lead. LL may stand for low lead, but it's still pretty lousy with it, way more than the old pump leaded fuel. It does have decent octane, even mixed 50/50 with unleaded prem will support a lot of compression or boost. Most guys running it straight (in toys likes bikes) are mostly wasting money IMHO. Modern bikes are for the most designed to run on good pump fuel so adding octane may only give you a smidgen more power if any. Tuned, with reworked timing, compression etc, the gains can be more.
Originally Posted By: V1
Hypothetically speaking, how would 100LL fuel run in a newer, fuel-injected motorcycle?
Originally Posted By: V1
Hypothetically speaking, how would 100LL fuel run in a newer, fuel-injected motorcycle?
In my opinion there isn't really a benefit to avgas or race gas only used occasionally. the benefit of lead is to lube the valve face and seat. only doing that occasionally IMHO won't really extend their life. Adding a bit of leaded race gas to every tank as a fuel additive could potentially lube the valves, but I don't know how much you'd have to add to make a difference.
If your bike was pinging or you wanted to modify it then running higher octane all the time would be good.
If your bike was pinging or you wanted to modify it then running higher octane all the time would be good.
Street trim on my GN is 100LL. I've run it for many years.
What I've noticed about AV gas is that I have to/can run quite a bit more timing with it, much more so than other race fuels.
It seems to have much better detonation resistance than 100 unleaded. I can run 19-20psi boost with 100 unleaded and 24psi with 100LL without knock. California 91 octane gets me 14psi if I'm lucky.
AV gas is the only fuel that actually makes the car feel a little sluggish before I crank the boost and timing. If you're naturally aspirated and can't turn up the boost but can advance the timing, I would use it in a mix. Straight would probably be a waste of money and it would probably make less power.
What I've noticed about AV gas is that I have to/can run quite a bit more timing with it, much more so than other race fuels.
It seems to have much better detonation resistance than 100 unleaded. I can run 19-20psi boost with 100 unleaded and 24psi with 100LL without knock. California 91 octane gets me 14psi if I'm lucky.
AV gas is the only fuel that actually makes the car feel a little sluggish before I crank the boost and timing. If you're naturally aspirated and can't turn up the boost but can advance the timing, I would use it in a mix. Straight would probably be a waste of money and it would probably make less power.
100LL will also not atomize properly in the short intake of a bike. This, plus the not needed additives, greatly contributes to exhaust goo, or "spooge". Even when the bike has the carb metering spot-on in all circuits, 100LL can still be seen making goo.
That being said, you can run 100LL in just about any bike and it isn't going to be the root of any damage. If the fuel you get causes a lean condition/detonation, then 100LL is a good alternative to the proper race fuel, at the expense of throttle response and a very low performance ceiling.
To really see much performance gain from a race fuel, it needs to be formulated for the specific application. The VP C-15 that Bubba has at his shop is also a very poor choice for the bike, as it just doesn't have the right distillation curve for a race bike. And knowing Bubbba, he probably has let all the light ends escape from his prized drum of race brew.
92 ron/mon is going to be sufficient in most, if not all, stock race bikes. Most never see the full potential of their engine running pump fuel anyway.
That being said, you can run 100LL in just about any bike and it isn't going to be the root of any damage. If the fuel you get causes a lean condition/detonation, then 100LL is a good alternative to the proper race fuel, at the expense of throttle response and a very low performance ceiling.
To really see much performance gain from a race fuel, it needs to be formulated for the specific application. The VP C-15 that Bubba has at his shop is also a very poor choice for the bike, as it just doesn't have the right distillation curve for a race bike. And knowing Bubbba, he probably has let all the light ends escape from his prized drum of race brew.
92 ron/mon is going to be sufficient in most, if not all, stock race bikes. Most never see the full potential of their engine running pump fuel anyway.
Originally Posted By: mjoekingz28
Isn't that too much octane?
for what?
Isn't that too much octane?
for what?
Originally Posted By: Steve S
Originally Posted By: mjoekingz28
Isn't that too much octane?
for what?
"Hot Rod" has proven that too much octane will actually decrease hp. back to back runs on the same motor, same dyno, same day.
Originally Posted By: mjoekingz28
Isn't that too much octane?
for what?
"Hot Rod" has proven that too much octane will actually decrease hp. back to back runs on the same motor, same dyno, same day.
I own an airplane and use leftover 100LL in various things from lawnmowers to dirtbikes. From experience, I can tell you that 100LL runs better than any pump gas in my emissions lean lawnmower and pressure washer. However it does cause a slight loss of power/throttle response in my Big Bore Zuma scooter and my 2 stroke dirt bikes. The 4 stroke dirt bikes run just fine on it. In fact, the valves seem to last much longer.
Originally Posted By: sunruh
Originally Posted By: Steve S
Originally Posted By: mjoekingz28
Isn't that too much octane?
for what?
"Hot Rod" has proven that too much octane will actually decrease hp. back to back runs on the same motor, same dyno, same day.
Depends on what race gas you're using. Going from memory, C-14 110 octane actually burns faster than pump gas. This gas feels faster per psi of boost. I have a feeling 100LL burns slow since I have to use so much timing with it. Luckily the Buick rarely sees north of 5,000rpm.
Originally Posted By: Steve S
Originally Posted By: mjoekingz28
Isn't that too much octane?
for what?
"Hot Rod" has proven that too much octane will actually decrease hp. back to back runs on the same motor, same dyno, same day.
Depends on what race gas you're using. Going from memory, C-14 110 octane actually burns faster than pump gas. This gas feels faster per psi of boost. I have a feeling 100LL burns slow since I have to use so much timing with it. Luckily the Buick rarely sees north of 5,000rpm.
FWIW, 50/50 93 pump and 100ll tests out to ~105 r+m/2, has worked well for me and is cheaper than comparable race fuel where you can use it. (rules have mandated unleaded in many race environments).
Id use straight 105 with a mix of 2 stroke oil mixed to 150:1 to 500:1 pending your bikes response.
This will give you great detonation resistance with awesome lubrication for the top end!
This will give you great detonation resistance with awesome lubrication for the top end!
A CBR1000RR?
Yeah, first, if you don't have an aftermarket exhaust, you will probably ruin the cat like someone posted.
What are you trying to accomplish? More power? A common leaded racing fuel for a car, be it VP fuels like C12, C14, VP110, Power Mist T111, T112, Cam 2, Turbo Blue, etc...
If you ran it straight, compared to pump gas, you're probably not going to gain power. Most likely, you'll have a decrease on top. Might clean up some of the lean conditions at middle RPM's because of the lighter specific gravity.
What we've found from experience on a road course is that if you want to make a little mix of some fuels four your bike, a mix of about 3 gallons of pump gas to on gallon of leaded racing fuel will give you an overall improvement. The fuel doesn't need more octane, but the leaded fuel will add a little lead that improves the front of the combustion while also adding some aromatics into the mix also.
This will work on 1000/4's, 600/4's, 750/4's. If you get into an RC51, the Superhawk, Ducati 999,998, 749, 748, the size and shape of their combustion chambers can be a bit different in their needs depending upon their state of tune. Sometimes they will react better with more octane.
Yeah, first, if you don't have an aftermarket exhaust, you will probably ruin the cat like someone posted.
What are you trying to accomplish? More power? A common leaded racing fuel for a car, be it VP fuels like C12, C14, VP110, Power Mist T111, T112, Cam 2, Turbo Blue, etc...
If you ran it straight, compared to pump gas, you're probably not going to gain power. Most likely, you'll have a decrease on top. Might clean up some of the lean conditions at middle RPM's because of the lighter specific gravity.
What we've found from experience on a road course is that if you want to make a little mix of some fuels four your bike, a mix of about 3 gallons of pump gas to on gallon of leaded racing fuel will give you an overall improvement. The fuel doesn't need more octane, but the leaded fuel will add a little lead that improves the front of the combustion while also adding some aromatics into the mix also.
This will work on 1000/4's, 600/4's, 750/4's. If you get into an RC51, the Superhawk, Ducati 999,998, 749, 748, the size and shape of their combustion chambers can be a bit different in their needs depending upon their state of tune. Sometimes they will react better with more octane.
Great info!
Yeah, a couple of my friends in college used 100LL regularly. They swore by it. So I've always been curious about that. Never tried it myself though.
Improved engine smoothness, valve protection and mixture control are all very desireable, but not at the expense of a converter. It seems like these fuels are much more suitable for modified engines.
Yeah, a couple of my friends in college used 100LL regularly. They swore by it. So I've always been curious about that. Never tried it myself though.
Improved engine smoothness, valve protection and mixture control are all very desireable, but not at the expense of a converter. It seems like these fuels are much more suitable for modified engines.
I've routinaly small mixes of vp c12, in my 4strokes(like a cup per tank or every other, I find the lead elimates virtually all carbon build up. It does poison the cat, but havent had any blockage issues in the 34,000 mile I've run it in a catted FI bike. I wouldnt run a full tank of even half a tank, way too much lead powder for the cat.
Ofcourse ya raise an eyebrow when running leaded racefuel in a fuel injected catted bike. But valve recession is still a big issue with Motorcycle engines.
The only other leaded I've run is sunoco and its not a clean as the Vp.
Ofcourse ya raise an eyebrow when running leaded racefuel in a fuel injected catted bike. But valve recession is still a big issue with Motorcycle engines.
The only other leaded I've run is sunoco and its not a clean as the Vp.
i have run Howell 001 and 002. the lead in my uoa's can almost tell you exactly how much time i went on that oil. my average is over 200ppm with my personal record being 651.
With the amount of lead I run, its usually less than 50ppm on a sub 2000 mile oil change, that shows up in the oil.
surprisingly, even a small dose seems to have a significant effect with carbon.
I never ran it on my 2 strokes, other than 1 time or 2, didnt see much benefit. My klx(no cat) was the first bike I started running the mix. It had sizeable amount of black carbon in the exaust. ran 1/2 tank of vp c12 with regular fuel, it completely eliminated all the carbon in the exaust. I ran that bike 40,000 mile with outstandin carbon cleanliness, even just running a cup per tank.
surprisingly, even a small dose seems to have a significant effect with carbon.
I never ran it on my 2 strokes, other than 1 time or 2, didnt see much benefit. My klx(no cat) was the first bike I started running the mix. It had sizeable amount of black carbon in the exaust. ran 1/2 tank of vp c12 with regular fuel, it completely eliminated all the carbon in the exaust. I ran that bike 40,000 mile with outstandin carbon cleanliness, even just running a cup per tank.
Valve recession prevention in a modern bike motor isn't what it was back in the day when the change was made away from leaded fuel. Hardened seats and valves if oft mentioned, but there is another factor. The iron engines (vs. alum and nicasil) resulted in iron oxide which would deposit on the valves and act like a grinding compound. The lead helped offset it. A modern bike engine won't see the same kind of benefit.
- Status
Similar threads
