Aggressive drivestyle

[i-DSi]

Originally Posted by alvaro84

i-DSi, if you're here, your theory about the different strength engines at different speeds now has some supporting data.
We had a longer (mostly freeway) trip to Slovenia with the 2 bikes and while it's easier to obtain good FE with the 250cc, 27hp Ciliegia at low speeds, Teresa won this round hands down, even though our pace was quite moderate (mostly 100-110km/h [62-68mph] by the speedo, sometimes up to 120, but kept the 130km/h [81mph] speed limit even at passing trucks). Ciliegia went up to 3.64l/100km while the 650cc, 50hp Teresa was hardly worse than under 90km/h, she could do this first, fastest segment with a fuel consumption of 3.17l/100km.

And, as my previous post shows, Teresa gets worse by 130km/h (81mph) too.
There was another longer trip in between, usually at 100km/h on the freeway, but in strong head/sidewind all the way. Now that was even worse than the 130km/h one...

I'm here! Thanks for confirming my theory. But indeed, it's a fact that 'a' combustion engine as we know it has a rather narrow area where efficiency is really good. And for my CBF this is in high revs. Confirmed again by my last addition in CBF gasslog: very good result (low consumption), allthough we drove like mad in the south of Belgium. My engine was revving up to 10.000rpms several times but consumption is low without any effort at all. Off course: emptying a tank without engine being cooled down is very beneficial for this result also.

@ Cat0020: I think Alvaro calculates the same way as I do (European): consumption in liters per 100 km (l/100km). Nothing special if you ask me.

[Jay2TheRescue]

Maybe this is why my first tank in my bike was disappointing... I never reved it high, and I kept it in the highest gear possible at all times. I averaged 42 MPG, but Harley's published ratings for the bike are 44 city, and 50 highway. That tank was mostly highway, but I was riding in the mountains, and further research on Harley's data shows that the published numbers reflect what the bike can do with "optimal laboratory conditions". I also found out that they account for a 180 lb rider, and me (220 lb) + my riding gear must weigh at least 235 or 240 lb. I'll have to try a few tanks with different throttle styles and see what works best.

[cat0020]

Originally Posted by Jay2TheRescue

Maybe this is why my first tank in my bike was disappointing... I never reved it high, and I kept it in the highest gear possible at all times. I averaged 42 MPG, but Harley's published ratings for the bike are 44 city, and 50 highway. That tank was mostly highway, but I was riding in the mountains, and further research on Harley's data shows that the published numbers reflect what the bike can do with "optimal laboratory conditions". I also found out that they account for a 180 lb rider, and me (220 lb) + my riding gear must weigh at least 235 or 240 lb. I'll have to try a few tanks with different throttle styles and see what works best.

I doubt reving high on a Harley V-twin would produce much better fuel efficiency. 40+mpg is really high.. unusually high IMO

[Jay2TheRescue]

Heck, I averaged just over 40 on my first tank which included me playing with the clutch, brake, and throttle in an empty parking lot. I'm sure I will be able to eventually do better, I was just expecting more considering I had kept it in 6th gear whenever possible. I guess that's more incentive for me to lose some more weight I would like to lose another 20 pounds if I can.

[alvaro84]

I use km and l units and calculate the fuel consumption in km/100l.
So I convert everything to miles and gallons whenever I update gassavers gaslog (I made an ods spreadsheet that does it for me, at least for the more complicated method I use in the case of Teresa). I have another gaslog at cleanmpg too, that allows me enter liters and kms - but they're consistent, of course
Gradually I get familiar with the mpg system, though gallons and miles are still unnatural for me, mpg is getting to make sense

About revving: I know I should try it, but it would feel sooooooo awkward... revving for nothing, it's so noisy and overzealous... plus the engine brake would get annoyingly strong, just when I almost gave up on it (I either coast down to a lower speed or just use the friction brakes if I have to do it quickly - the only case I use engine braking is to keep a lower speed downhills, and then I try to use forced DFCO to get zero fuel consumption) and would complicate coming out of coasting (I find rev matching easier at lower rpms).

[theholycow]

Rev-matching may seem weird at first but it is a great technique for faster shifting and reducing wear on your equipment. I don't rev-match for DFCO, I just accept the wear. However, during engine-on Pulse & Glide when I go from neutral to a gear, I double-clutch rev-match...I get into gear quicker and avoid extra wear.

I'm not sure I understand what you're saying about engine braking. DFCO only works while engine braking.

[alvaro84]

Originally Posted by theholycow

I'm not sure I understand what you're saying about engine braking. DFCO only works while engine braking.

The thing is that I only use engine braking for downhills when coasting would give uncontrollable (or just too illegal) speeds, and this is when I force DFCO with the kill switch (it seems effective at lower rpms, DFCO apparently would not kick in otherwise).
But otherwise I don't use it that much anymore, but slow down by coasting (mostly with the engine on, but definitely FASed before stopping) anytime I can (and rev match to keep going and/or pulse).

Bump starts are a bit rough for me, but if I'm in forced DFCO, I can keep the engine rolling by turning it on by the killswitch and depressing the clutch at the same time. Before I tried it I was afraid that it would cause a twitch, but it's smooth

[i-DSi]

Originally Posted by alvaro84

About revving: I know I should try it, but it would feel sooooooo awkward... revving for nothing, it's so noisy and overzealous... plus the engine brake would get annoyingly strong.

Hi Alvaro, maybe you misunderstand me, but I'm not revving 'for nothing'. I'm only at FULL throtlle in higher revs. I hate it to rev up with half throttle. Has no use if you ask me. Only do it when I need full engine power.

@ Jay, I agree with Cat0020, reving a Harley is unnatural and can be disappointing. Do you know if the correct oil is in it?

[theholycow]

Wait a minute...I think I was confused in my last post in this thread about rev-matching and DFCO. I think I thought I was in a different thread.

alvaro84, I wasn't thinking about motorcycles in that post, so please exercise due caution when trying to apply what I said to motorcycles. Also, aren't most motorcycles equipped with carburetors (which can't DFCO)?

[i-DSi]

Originally Posted by theholycow

Also, aren't most motorcycles equipped with carburetors (which can't DFCO)?

Oh no they aren't Holycow. Mine has even a catalyser with lambdasensor. And I think Alvaro's one also. Tsss... Holycow.
Constructors must apply 'Euro3' exhaust regulations here in Europe and that's impossible without FI, lambdasensor and catalyser.

Carburettors on european motorcycles were applied until approximately 2004 if I remember well. But a lot of manufacturers started with FI for performance reasons (Honda, BMW, Yamaha...) a lot earlier (in the 90's) on some models.
BMW even in the 80's on the 1983 K100.