The alcohol is added into the fuel as a way to increase octane as ethanol has an octane of 110 (i believe). However it actually has less Joules/L of fuel when compared to gasoline. so the more alcohol present, the less mileage/L you will get.
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Ok fuel milage one more time.
- Thread starter itinkle
- Start date
The alcohol is added into the fuel as a way to increase octane as ethanol has an octane of 110 (i believe). However it actually has less Joules/L of fuel when compared to gasoline. so the more alcohol present, the less mileage/L you will get.
Comrade Yeti
Member
5W30 oils without energy conserving additives are rare... I doubt the OP is using the correct oil. He should be using a 10W40 (non-energy conserving). If the OP is using a 5W30 with energy conserving additives, then his clutch is slipping and that's a good start to explain the lower mileage.
strictlye
Well-known member
I get the EXACT same mileage with the same bike as you. Its frustrating but normal. Thats what we get for having 16.5L tanks not 17L tanks. The gas light comes on around 150km but I can push it about 200kms.
Also,
I think because these bikes do nothing below 6k rpm, we are forced to ride at higher rpms which burn more gas. my bike bogs below 6k and I like to ride in the power band around 9-10k rpms.
My '10 GSX-R 600 owner's manual recommends 10W-40 and 87 octane. Putting in premium when the manufacturer recommends regular is just throwing your money away.
No and no (assuming you do a complete oil and filter change).
Basing your fuel economy on the size of your tank and when the light comes on is never going to be a good way to measure actual fuel economy on any vehicle. Here is the process that works for everything:
1. Fill vehicle's tank to maximum.
2. Record odometer reading.
3. Use vehicle until you need fuel again. For best results run it as close to empty as you feel comfortable as the numbers get less accurate with smaller numbers.
4. Fill up to the maximum again and read odometer.
5. Compare the difference in odometer readings to how much fuel you actually put in the tank.
You can avoid some math using a trip meter. This method means that the size of your tank has absolutely no impact on your fuel economy readings. There are several websites that will do all the calculations for you (such as fuelly.com).
It's like when one person is talking to another and says to one guy, "My car gets 800 km to a tank!" and the other guy goes, "Oh, my car only gets 600 km to a tank, I should buy a car like yours." Then you do the actual comparison and find that one guy's car has an 80L tank and the other guy has a 40L... the guy getting less distance out of a tank is actually getting better fuel economy.
strictlye
Well-known member
i got a K8 and I too get the light on around 150km.... Using 91 octane and 10w40 oil.
I get sad every 150 km
ok well, your tank is bigger than ours so there is DEFINATELY something wrong with yours. lol
Here is the problem ... the vast majority of "custom maps" have been set up using a full-throttle run and then calling it good enough. Most of the rest have been set up by someone who thinks 12.8:1 air/fuel ratio is "perfect" and they proceed to set it to that everywhere in the RPM range, even at part throttle. Dynojet themselves are not immune to this, because apparently the "autotune" function doesn't work if you specify an air/fuel ratio leaner than 15:1.
If you really want to get good fuel consumption, it needs to be *lean* throughout the part-throttle region. Spark-ignition gasoline engines (which is what you have ...) normally give best Brake Specific Fuel Consumption when the air/fuel ratio is somewhere near 16.2:1 and there is some give or take in that. Lean misfire should be north of 18:1 unless you are getting too much exhaust reversion, but on bike engines with a separate throttle per cylinder, that's usually not a problem. (Note that the air-suction device needs to be blocked in order for a lambda sensor to properly read the air/fuel ratio that the engine is actually seeing.)
Full load needs to be in the 13:1 range to avoid burning stuff up. But you're never going to burn an exhaust valve when cruising around with the engine running at 1/10 of rated power output.
The tricky bit, which is why most people that you PAY to make a "custom map" won't touch this strategy with a ten foot pole, is that the engine is more fussy-finicky on the lean side, than it is on the rich side, which means it takes A LOT of time and effort to get the map correct. You end up running just short of the point where the throttle response starts going flat - but that's the sweet spot for fuel consumption - and you need to set this right for every spot in the map at 0%, 2%, 5%, 10%, and 20% throttle, every 250 rpm from idle and all the way up. It takes A LOT of fiddling.
It is particularly tricky to get the cracked-throttle correct with this strategy. You can't do it on a dyno, because the engine is effectively in coastdown. I did it in North Carolina on a really long, steep downhill with an air/fuel gauge on the bike, so that I could get the air/fuel right (lean!) just as the engine came in and out of deceleration fuel cutoff - this is what determines that annoying lurch that a lot of fuel-injected bikes have when you crack open the throttle just a wee bit.
Some engines will want the ignition timing advanced slightly for the engine to not run hot by doing this. My FZR400 (carb'ed ... but set up with the same strategy) didn't care. My ZX10R wanted the timing advanced 3 to 4 degrees across the board. With that done, it runs same temperature as it always did.
It is a lot of work and you can essentially only do it yourself if you have an air/fuel ratio gauge that you can install on the bike, even if only temporarily. BUT, the benefit is that you'll get a big improvement in fuel consumption and range, and the engine won't carbon up spark plugs or piston rings any more, and it won't make the engine oil stink like fuel (due to fuel dilution) any more. Last fill-up on the ZX10R took 12.1 litres to go 234 km on the road (correcting for odometer error due to gearing, speedohealer, etc) ... 5.2 L/100 km ... and that's with shortened gearing on the bike. Low fuel light hadn't come on yet.
optionfa
Well-known member
Great writeup brianP, as much as a lot of this stuff is over my head this explained a lot.. I probably will just accept the bad fuel economy as a side effect of the PC5 but the surge when getting back on the throttle is particularly annoying when leaned over mid corner.. I was originally going to pay for a dyno tune to smooth this out but from reading your post it seems like it might be a waste of money. I may just look into playing with the numbers in the 0-5% throttle range and see if I can eliminate some of the choppyness.
why would you accept the poor fuel economy from a piece of equipment that is designed to fix this sort of thing??
why did you buy the PC5 if you don't plan to make use of it?
why did you buy the PC5 if you don't plan to make use of it?
Here is what I'd do, if you have the autotune function.
Make a target air/fuel map as follows. For 1250 rpm and higher (don't touch 1000 rpm and below), set it for 15:1 (the leanest possible) everywhere 20% throttle and below, 14.2:1 at 40%, 13.0:1 for all higher throttle positions. For 4000 rpm and below, do a cut-and-paste and copy all of this down to the next lower throttle position (14.2 at 20%, 13.0 at all higher). This is because the engine reaches full load at a smaller throttle position at low revs.
Now let the autotune do its thing. You will probably find at this point that coming out of decel fuel cut gets WORSE. (My experience has been that it's worst near stoichiometric and gets better as you go away from that in either direction.)
Once it has settled down and you have blended out any rough spots, for all settings 20% throttle and below at 1250 rpm and above, do the following manual recalibration:
"New number" = rounded up to next higher integer ((100 + "old number") * 0.926) - 100
This takes whatever setting it has zeroed in on to get 15.0:1, and calculates a new leaner setting to get 16.2:1. Pay attention to the sign of the number. For example, if autotune has placed a "-12" in a certain cell, then the calculation goes:
100 + (-12) = 88
88 x 0.926 = 81.488
81.488 - 100 = -18.512
round it up to the next higher (richer ... less lean ...) number = -18
and that's the new number you plug into that cell.
There is the distinct possibility that the autotune won't give you anything at small throttle settings. Copy the number from the lowest throttle position that it's giving you something at any given RPM, all the way back to 0% throttle setting.
Certain spots on my ZX10R map are taking away -36% on the map ... That's what it took to get from the way too rich stock map to a proper "lean cruise" setting ...
Make a target air/fuel map as follows. For 1250 rpm and higher (don't touch 1000 rpm and below), set it for 15:1 (the leanest possible) everywhere 20% throttle and below, 14.2:1 at 40%, 13.0:1 for all higher throttle positions. For 4000 rpm and below, do a cut-and-paste and copy all of this down to the next lower throttle position (14.2 at 20%, 13.0 at all higher). This is because the engine reaches full load at a smaller throttle position at low revs.
Now let the autotune do its thing. You will probably find at this point that coming out of decel fuel cut gets WORSE. (My experience has been that it's worst near stoichiometric and gets better as you go away from that in either direction.)
Once it has settled down and you have blended out any rough spots, for all settings 20% throttle and below at 1250 rpm and above, do the following manual recalibration:
"New number" = rounded up to next higher integer ((100 + "old number") * 0.926) - 100
This takes whatever setting it has zeroed in on to get 15.0:1, and calculates a new leaner setting to get 16.2:1. Pay attention to the sign of the number. For example, if autotune has placed a "-12" in a certain cell, then the calculation goes:
100 + (-12) = 88
88 x 0.926 = 81.488
81.488 - 100 = -18.512
round it up to the next higher (richer ... less lean ...) number = -18
and that's the new number you plug into that cell.
There is the distinct possibility that the autotune won't give you anything at small throttle settings. Copy the number from the lowest throttle position that it's giving you something at any given RPM, all the way back to 0% throttle setting.
Certain spots on my ZX10R map are taking away -36% on the map ... That's what it took to get from the way too rich stock map to a proper "lean cruise" setting ...
If I'm not comfortable, I stop for gas and a coffee after 100km, If I'm comfortable I can go 300km before stopping for gas
icecube172
Well-known member
i have a 08 R6s and I get about 230km before the light comes on
optionfa
Well-known member
Very informative post, I don't have the autotune module but after reading this I may end up getting it. I'm gonna try these steps with my open loop system hopefully I see some improvements, if not I can always switch back to my custom map.
Brian, is there a transient throttle multiplier in the calibration menu for PC3 or PC5? I find you can usually trim the static tables even further as long as their is a transient compensation or a tip in + tip out table.
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