Mileage

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Aug 16, 2008 | 02:20 PM

#21

iclick

Extreme HDF Member

Joined: Sep 2005

Posts: 11,615

Likes: 50

From: Baton Rouge, LA

Quote:

Originally Posted by sortasuave

I just got back from a 2600 mile trip and found a few things effect my milege...

1) The obvious, city vs highway
2) The amount of time the engine spends at full running temp. For example, I noticed the 2nd and 3rd tank while going down the highway always did better then the first. I attribute this to the bike running at "normal" operating temps while on that specific tank of gas. I found on the trip that it took about 30 min or so to get to this temp. (Note that the oil temp sending unit is in the pan)

I think you're dead-on here. My mileage is way off its max (40 vs. 50 mpg) when I make numerous cold starts, as it does take quite a while to reach normal operating temperature. At least part of that period is when the EFI is in cold mode, which means richer mixtures. My understanding is that this is an on-off function, although I've never noticed a switching point based on the bike's feel.

Quote:

3) Altitude - The higher up I got (colorado) the hotter my bike ran and the better my milage (Had a high of 57 MPG)

Higher altitude means less air density, and to keep A/F the EFI compensates by adding less fuel, even in open-loop mode via the MAP sensor. Power will obviously be down, too. I noticed better mileage and less power with my old CV-carbed RK, but haven't been higher than 5k feet on the newer bike.

Quote:

4) The bike does better overall if the RPM's are above 2500 for milage. That includes running it in 5th gear vs 6th for long distances.

This may be true and I've heard this suggested before, although I haven't really been able to prove it one way or another on my bike in actual experience. On a recent ride I tried to keep the bike in 5th gear more and mileage was a tad lower, but I can't say what else may have been a factor here. I normally don't shift into 6th until I can go at least 2200 in that gear. Throttle position is little or no different, and any small change would not put me in a different part of the PCIII map, so I can't see why you'd get lower mileage in 6th vs. 5th. If TP threw the EFI into a richer mode I can see it, though, but otherwise I would think the lower RPM would mean better mileage. It could be that since you're running a far-different EFI setup (TBW and closed-loop) than my '07 SG (cables and only open-loop with the PCIII) that we could have different effects in 5th vs. 6th gears.

Last edited by iclick; Aug 16, 2008 at 02:22 PM.

Aug 16, 2008 | 02:59 PM

#22

1Reaper

Thread Starter

Road Master

Joined: Oct 2007

Posts: 755

Likes: 1

From: Denver

That all makes sence, most of my driving during the last two takes has been to work and back, 41 miles each way in traffic, so 41 seems good.

Aug 16, 2008 | 03:57 PM

#23

glide2005

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Joined: Jul 2007

Posts: 2,196

Likes: 10

From: Shenandoah, TX

Now I'm really pissed.Ya'll are getting great mpg,and I'm getting crap.My stock mpg was 35 at best,everyone said try a V&H Fuelpak to better your mpg.Well,the best I got with the FP with 8 different maps from V&H tech themselves was 28 mpg.So,I sold the FP and bought a PC III from FuelMoto and Jamie premaped it and now I get 26 mpg.WooHoo.He sent me another map via email and I can't open the attchment.So I'll have to wait till Monday and get him to fax it to me.

Aug 16, 2008 | 04:11 PM

#24

iclick

Extreme HDF Member

Joined: Sep 2005

Posts: 11,615

Likes: 50

From: Baton Rouge, LA

Quote:

Originally Posted by glide2005

The map can be tweaked for mileage without sacrificing performance, although heat may increase a bit due to leaner mixtures at cruise. My bike runs fine with my latest tweak and has gotten up to 50mpg on slow, unaggressive rides on the backroads. On the low end it may get as low as 38 in cooler weather in city riding when making numerous cold starts, which kills mileage. Oil temps stay <210° while moving, even in summer, but I'm running synthetic oil and an oil cooler, both of which reduce peak oil temps.

Jamie creates his maps for cooling and performance, but mileage will suffer. To be honest, I have a map switch on my PCIII (optional accessory) and I can switch to Jamie's rich map on the fly when the going gets hot. I see little difference when I switch, so I'm not sure cooling is affected that much, or perhaps it takes a while after a map change before oil temp is affected.

If you are running his custom baffles, I will send you my map. All I ask is that you watch oil temps and let me know how you do, as if you don't have an oil cooler you may run hotter, but likely not as high as stock. One guy who installed my map without a cooler said he hadn't exceeded 220°, but he's the only person who's responded about oil temps out of maybe 10 who've asked for the map. Several reported back that mileage increased greatly, one claiming a 10mpg increase. I accidentally left my switch in the wrong position one day and got 43mpg when 50mpg would've been expected.

Also, I'm not an aggressive rider, so if you are constantly on the throttle and keeping RPM's high you will not get great mileage, but you should be able to do much better than you describe. My tweak affects only 0-3k RPM's and mostly 0-20% TP, so if you get out of that range you are outside the good-mileage range and within Jamie's original map. My tweak is designed to increase mileage while cruising on the highway.

Last edited by iclick; Aug 16, 2008 at 04:16 PM.

Aug 16, 2008 | 06:31 PM

#25

jimbobweh

4th Gear

Joined: Aug 2008

Posts: 8

Likes: 0

Kinda funny folks worrying about gas mileage after hoppin up their bikes. I put a stage 1 big bore kit and screaming eagle slip-ons on my '04 Road King Classic. I rode it for 3 years before even thinking about measuring mpg ... the one time I measured it I got 42 mpg. On that tank I probably did mostly city driving between Lafayette and Boulder, CO and gunned it at least 3 times.

Aug 16, 2008 | 06:44 PM

#26

dirtdobber

Elite HDF Member

Joined: Jul 2007

Posts: 4,749

Likes: 16

From: sand mountain Alabama

Quote:

Originally Posted by iclick

I have an '07 with the smaller tank, and although HD specs it at 5.0 gallons it holds more. My old '96 RK, which I believe had an identical tank, held 5.4 gal. when precisely measured. Anyway, my '07's warning light comes on when about one gallon remains, which may be why yours had not yet illuminated. Usually the gauge shows about 1/4 at that point, but it can be lower, so I wouldn't rely on the gauge when it shows <1/2. At the 1/2 point mine has used 3.2 gal., so it isn't linear.

Basically, you can depend on two things: First, if the light comes on, gas up ASAP regardless of what the gauge shows, as you don't have much left. Second, don't assume you have only a 6.0 gal. capacity. To find out, drain the tank completely and add gas one quart at a time like I did on my old bike. I wanted to know so I could ascertain exactly how many gallons I had in the tank when it hit reserve (carbed). The crux is to do your own tests so you know the behavior of your own bike, as I think two bikes will likely be different.

That is one way but thats a lot of work for me. I just put 1 gallon in a can put it on the bike and run it out till it stops. Put the gallon in and fill up. Of course you need to be close to a station to really know. Mine held 5.3 gallons when empty at 47.7 mpg.
problem solved
I do not trust the fuel gauge but it does give me a idea when I might need fuel. I reset one of my trip meters and fill at 170-180 miles.
jim

Last edited by dirtdobber; Aug 16, 2008 at 06:56 PM.

Aug 16, 2008 | 08:36 PM

#27

glide2005

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Joined: Jul 2007

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From: Shenandoah, TX

I am running one Jamies custom maps at this time,but with no luck.When cold,its slugish and I have to gun it to make it clear up.Like its trying to flood.When its hot or running temp,it runs fine.My setup is V&H true duals,V&H basic slipons,K&N a/c and stage 1 down load, thats all.

Aug 16, 2008 | 09:33 PM

#28

Bertk

Ultimate HDF Member

Joined: Mar 2008

Posts: 5,788

Likes: 203

From: SW Florida

Quote:

Originally Posted by rbabos

In fact the fuel gauges are accurate but it's where the empty part is calibrated is what causes the problem. Some tanks may contain up to 2 gallons of reserve left when the fuel light is on. 1 gallon would be better, but all you have to do short of bending the float rod and recalibrating it is to get use to your own gauge readings. I seems to always repeat it's readings with the odometer. Miles per tank would only be meaningful if you ran it dry, but fuel cools the pump and it's not a bad idea to keep at least 1 gallon in there for that purpose. My milage varies between 41-44 with tmax, depending on my mood.
Ron

"In fact the fuel gauges are accurate but..." means it is inaccurate.