Pulse and Glide for competition. Added mass?

[user removed]

You should try a vacuum gauge or another means of precisely measuring load. It's not full throttle if you are in higher gears. You can drop manifold vacuum to 0 even at 25% throttle if you are in high gear at low enough speeds, and that seems to be your average in the competition.

Like most things it can be too little and too much. I would make sure you did not get into any full throttle-full load enrichment, but it's been my experience over many types of vehicles that you can go too much and too little with load and gearing. Find the sweet spot and stick to it like glue. The longer you can glide on a bike the better, which is a reason for ballast, but it may also mean you need to accelerate in a lower gear to prevent excess load from prolonging your pulse phase.

If you can get your pulse to glide ratio up to 1 to 3 you should be doing fine, but on a bike the aero will slow you down much faster, which can be mitigated by your tuck, other aero, and higher sectional density (added weight).

Get that all coordinated and it will be hard for any other vehicle to beat you unless it's something real unusual.

regards
Mech

[sendler]

Originally Posted by Old Mechanic

You should try a vacuum gauge or another means of precisely measuring load. It's not full throttle if you are in higher gears. You can drop manifold vacuum to 0 even at 25% throttle if you are in high gear at low enough speeds, and that seems to be your average in the competition.

Like most things it can be too little and too much. I would make sure you did not get into any full throttle-full load enrichment, but it's been my experience over many types of vehicles that you can go too much and too little with load and gearing. Find the sweet spot and stick to it like glue. The longer you can glide on a bike the better, which is a reason for ballast, but it may also mean you need to accelerate in a lower gear to prevent excess load from prolonging your pulse phase.

If you can get your pulse to glide ratio up to 1 to 3 you should be doing fine, but on a bike the aero will slow you down much faster, which can be mitigated by your tuck, other aero, and higher sectional density (added weight).

Get that all coordinated and it will be hard for any other vehicle to beat you unless it's something real unusual.

regards
Mech

I have a cool, thirty year old, cheapo fuel pressure/ vacuum gauge with a 4 inch face that I bought for $6 at the auto parts store that would be a chuckle, yet practical to stick on the dash.
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Hitting the target rpm range is obviously important. No sense gunning it in a gear that has no pull. At the correct rpm the difference in efficiency between near wide open throttle and 90% is very small as long as the FI stays in closed loop. I may play with a set screw or cable clamp as a lock out to prevent WOT.
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Someone had a home built, wooden frame, diesel, three wheeler that got 160mpg. I don't know if he really dares to take it out on the road though. Maybe I can win the 140 mile road rally on Saturday.
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I'm not going to go crazy on this bike as I hope to get a 125 soon and make this my competition vehicle. That bike will get a wide band logger and fuel controller to allow some lean burn settings.

[ConnClark]

If your going to add weight to extend gliding add it to the wheels. Not only will you get the inertia from forward momentum but you will get the rotational inertia as well.

Now if you can only find cast iron rims for your car.....

[sendler]

I rode the Mid Ohio Vetter challenge with 70 pounds of gear on my bike and did 105 mpgUS. I did 95 over the road on the 440 mile trip to get there. Adding mass to a motorcycle will improve the effectiveness of PnG and is only a detriment if you have to do a lot of braking.

[brucepick]

Originally Posted by sendler

I rode the Mid Ohio Vetter challenge with 70 pounds of gear on my bike and did 105 mpgUS. I did 95 over the road on the 440 mile trip to get there. Adding mass to a motorcycle will improve the effectiveness of PnG and is only a detriment if you have to do a lot of braking.

Thanks sendler -
I'm about to add an approx. 65 lb. deep cycle "Group 29" battery to my car to support extended headlight use and longer trips with the alternator disabled (intentionally of course). I'll remove the approx 26 lb. oem starting battery so the net gain will be about 40 lb.

I came to the same conclusion as you, tentatively. I appreciate that you tested and analyzed the question to the extent that you did.

Some of us are driving in the 2012 Boston Greenfest One Gallon Challenge, Aug. 16. Interested? I'm not registered yet but I'm working on it.

[sendler]

Originally Posted by brucepick

Some of us are driving in the 2012 Boston Greenfest One Gallon Challenge, Aug. 16. Interested? I'm not registered yet but I'm working on it.

I had talked to them. Maybe next year.