latest mpg

[thewiz]

Well, Plane ...

You probably woulda' seen a mileage increase but for the fact that you've seldom slowed down to under a hundred since you put it in there . Hell, even with the higher final drive ratio, a bit more fuel tends to be burned at those kinda' speeds .... just a bit, don't ya' think?

[Crazcnuk]

Yes, if you don't take efficiency ranges into effect. But since we already have many people here who report increased fuel economy with the 750 mod, I think that's kind of silly.

Next time you go on a trip in the car, do it in 2nd gear and see if the fuel economy stays the same!

My buddies 2008 Electra-Glide Ultra Classic weighs in at 880lbs, and he gets 55mpg. It revs at 2500rpm@70mph.

[planedick]

Samo samo

I haven't changed my riding style since before I did the mod and the mileage remains the same. I do get really good mileage when I drive slower. I have even aproached 40 mpg. While on a group ride where speeds are closer to 50 mph I get about 38 mpg, but it was the same with the original final. My extended range is because I learned how to overfill the tank when on ling trips.

When I said it takes the same energy to do a task whatever gear I mean within reason and the power band. That means 50 mph up a hill can be done in 4th or 5th and with the same fuel consumption in either gear.

Do you know what happens when you inject water mist in the combustion process?

[wa407mpp]

It makes the air denser by cooling it and also the oxygen in the water burns during combustion creating a fuller burn, that way increasing mileage and power. My dad used to build fast cars,from the late thirties through the sixties, and he used water injection on a lot of his cars.

[xschop]

MPG's

I tore out the 4x4 transaxle and 4-speed transmission from my old 2.8L S10 and put in a 5-speed from an Iroc Camaro with a taller 5th gear obviously and went from 23 Mpg's to 30 on the hiway (she also Likes 70 MPH). As long as you keep your foot out of it (throttle for our XS's) then you will see an increase in Mpg's. I personally think that more torque of the 4-2's is the determining factor for best performance with the lower ratio.

[FSCGunslinger]

Re: MPG's

Originally posted by xschop
I tore out the 4x4 transaxle and 4-speed transmission from my old 2.8L S10 and put in a 5-speed from an Iroc Camaro with a taller 5th gear obviously and went from 23 Mpg's to 30 on the hiway (she also Likes 70 MPH). As long as you keep your foot out of it (throttle for our XS's) then you will see an increase in Mpg's. I personally think that more torque of the 4-2's is the determining factor for best performance with the lower ratio.

So with the 750 FD mod, 4-2 exhausts are best? Why is this? What makes them better than 4-1 (for weight) or 4-4?

[TopCatGr58]

Hey Gunslinger,

The 4-1 pipes are designed for better scavenging at the higher rpm ranges, ~5K+ and will flow more air there. The 4-2 pipes provide a little more backpressure and are tuned for a more efficient flow across more of the rpm range, specifically the lower range thru the mid and high, but not as good at the higher band than the 4-1.

So...the engine will run better in the lower rpms with the 4-2's, which helps to keep the fuel consumption rate down for "modest" highway speeds. Fuel use will also increase with increased speed due to wind resistance. There's a point of diminishing returns with respect to engine speed and vehicle speed and wind resistance, where it takes just as much or more fuel to push the vehicle/bike thru the higher wind resistance at a higher speed, even with a lower rpm than to ride/drive a bit slower. This is partly why IF you have the 750FD but you drive at much higher road speeds with much higher wind resistances, you'll probably NOT see better mileage rates compared to if you rode it at slower road speeds. All in all YMMV on many factors!!
T.C.

[geniusloerts]

31mpg!!!!!

OK, this last tank i got 31MPG

not bad. alot better than my truck

[manshack_one]

Ran 110 miles today and wound up with 29.29 MPG. Never went over 70. Need to get better mileage out of it or else I'll have to keep taking the Hyundai to work. It gets 31 and every little bit counts nowadays.

[FSCGunslinger]

Originally posted by TopCatGr58
Hey Gunslinger,

The 4-1 pipes are designed for better scavenging at the higher rpm ranges, ~5K+ and will flow more air there. The 4-2 pipes provide a little more backpressure and are tuned for a more efficient flow across more of the rpm range, specifically the lower range thru the mid and high, but not as good at the higher band than the 4-1.

So...the engine will run better in the lower rpms with the 4-2's, which helps to keep the fuel consumption rate down for "modest" highway speeds. Fuel use will also increase with increased speed due to wind resistance. There's a point of diminishing returns with respect to engine speed and vehicle speed and wind resistance, where it takes just as much or more fuel to push the vehicle/bike thru the higher wind resistance at a higher speed, even with a lower rpm than to ride/drive a bit slower. This is partly why IF you have the 750FD but you drive at much higher road speeds with much higher wind resistances, you'll probably NOT see better mileage rates compared to if you rode it at slower road speeds. All in all YMMV on many factors!!
T.C.

Thanks T.C.! That helps me understand exhausts a little better now!

[xschop]

coils

also, as mentioned on the UK website, if your coils are old, MPG's performance suffers. I have the Dyna 1.5 ohm coils installed and also noticed better MPG's before I ever did the 750FD mod. If your carbs are not at full tune you will find out right away after the FD swap. My buddy's carbs were rich and had a low end stumble we discovered after the FD swap....Jat....Chop

[egleaves]

I'm thinking about upgrading my coils to bring them into the new century. Anyone have estimates on their mpg/power increase with this upgrade? Just wondering how big of a hurry I should be in considering the coil cost.

[81xsproject]

To add to your new coils, I highly recommend getting more power to them. the mod is done on a lot of other old bike forums so I thought I would try it on mine (before I got the MSD's). There is a write-up and diagrams HERE. The difference was very noticeable on my bike afterward.

[7911special]

I'm pushing 33mpg If I ride easy on mine, all stock except for 4-1. It runs slightly lean as well.

My drive is stoplight every mile or so, not the greatest for determining mpg.

[xschop]

heres some other happy customers

http://www.benefiscal.co.uk/forum/in...p?topic=3320.0