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Discussion Starter #1
OK, as I've written about earlier, I've had my ST3s fully tuned with the DP perf kit, ecu, exhaust, air box and PCIII w/dyno tune and custom map. The bike runs AWESOME! BUT, the economy has gone down 25%+ to 32mpg over the last two tanks. This really sucks when considering the bike for its touring abilities as the range is less than 150 miles now. the gas light comes on at 120-125 miles.

Should I de-tune it to improve it's range? I kind of feel like I've thrown money to solve one problem and have now created another.
 

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OK, as I've written about earlier, I've had my ST3s fully tuned with the DP perf kit, ecu, exhaust, air box and PCIII w/dyno tune and custom map. The bike runs AWESOME! BUT, the economy has gone down 25%+ to 32mpg over the last two tanks. This really sucks when considering the bike for its touring abilities as the range is less than 150 miles now. the gas light comes on at 120-125 miles.

Should I de-tune it to improve it's range? I kind of feel like I've thrown money to solve one problem and have now created another.
A good tuner should be able to lean it out a bit under part throttle cruise conditions to restore your mileage. Unfortunately, good tuners are hard to find. The Dynojet dynos are connected directly to the PCIII and they do an auto-map, which doesn't consider fuel mileage, only air-to-fuel ratio. The target ratio is usually around 13:1, which is not optimal for mileage, but is good for performance and driveability.
 

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dumb and dumbmer,sell the bike -go buy your self a moped for mileage.
I have ridden with Marty and I think you have missed his point. A 120 mile gas tank may be fine for a cruiser or a sport bike, but a touring bike with at least a 200 mile range is almost a necessity up here in the PNW as there are great riding areas where gas stations are few & far between and not always open 24/7.
 

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Gas Mileage

This is a problem I am facing also. My ST 4 gets 45 mpg, my ST2 gets 35. this is not right. Plugs aren't black, it runs perfectly, I am in the process of switching sensors and ecu's are next, cleaned air filter , I am baffled that it can waste that much gas and run so well? I know I have had 5-6 ST's and these can get 200 miles out of a tankfull of gas .


OK, as I've written about earlier, I've had my ST3s fully tuned with the DP perf kit, ecu, exhaust, air box and PCIII w/dyno tune and custom map. The bike runs AWESOME! BUT, the economy has gone down 25%+ to 32mpg over the last two tanks. This really sucks when considering the bike for its touring abilities as the range is less than 150 miles now. the gas light comes on at 120-125 miles.

Should I de-tune it to improve it's range? I kind of feel like I've thrown money to solve one problem and have now created another.
 

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Discussion Starter #5
A good tuner should be able to lean it out a bit under part throttle cruise conditions to restore your mileage. Unfortunately, good tuners are hard to find. The Dynojet dynos are connected directly to the PCIII and they do an auto-map, which doesn't consider fuel mileage, only air-to-fuel ratio. The target ratio is usually around 13:1, which is not optimal for mileage, but is good for performance and driveability.
My mechanic is a very good tuner - for performance. He hand maps the PC-III maps on a Superflow dyno, and the results are fantastic. The ridability and performance are like night and day and the dyno charts back up the results. But the economy for a *touring* bike just isn't there anymore. 180+ mile range is a necessity on a multi-state, multi-thousand mile tour irrespective of mpg. If I could put a 7 gal tank on the bike the problem would be solved.

I need to talk to the mechanic and see if I can get two maps and change them on my own via the PC-III, one for economy and one for performance.
 

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I need to talk to the mechanic and see if I can get two maps and change them on my own via the PC-III, one for economy and one for performance.
That was going to be my suggestion. You could just load the all zero map for out right touring as an option. Must really depend on the bike and tuner. My old SS 900 had a PC3 with a custom map. I remember the mileage improving at normal commute / cruising around stuff. Of course, when ridden hard, it would be another store.
 

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Discussion Starter #7
From the data files I got after tuning it's clear it's running much richer in the 4000-5000 rpm range, and generally richer overall. I'm definitely going to have to talk to my guy and see if there's a middle ground to lean it out some and still retain some of the performance smoothness. The added richness <5000rpms explains why it seems to be sucking the gas down in everyday riding.



 

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Discussion Starter #8
That was going to be my suggestion. You could just load the all zero map for out right touring as an option. Must really depend on the bike and tuner. My old SS 900 had a PC3 with a custom map. I remember the mileage improving at normal commute / cruising around stuff. Of course, when ridden hard, it would be another store.
ooh, that's a good idea and won't cost me a dime of mechanic time.
 

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Have you told your mechanic about your gas mileage yet?

I know that sound like a stupid question but they can't tell on the dyno what the mileage will be and there is no "perfect" setting with a PCIII or anything else, they can indeed tweek it and still save performance. I believe their are load based settings that can be adjusted, when there is no real load (cruising) at a certain RPM it can give less fuel for example. Makes a huge difference in fuel economy and won't affect anything when you whack open up the throttle because that is a different load triggering more fuel.

Minor adjustments make big differences but the (mechanic) won't know unless you bring it to their attention because they are adjusting from a machine not a mountain twisty road at elevation in the PNW. I find it interesting that people blow off mods to: "add mods and get horrible fuel economy, now live with it." It is so lame. Ultimately, your performance will go up and your economy will go down, that much is not rocket science. I think we have to realize that DYNOS ARE NOT REAL WORLD.. I have all of your mods and am in the over 40 mpg+ range. Took a bunch of tweaking with my Techlusion which adds fuel and is a load based system. I would ride it, adjust it, ride, adjust, many times even after a dyno run. If people are not willing to go through that process after mods, then I think they should save their money.

Next time you are at a racetrack watch how many times they put the bikes on a "dyno" to dial it in to have the bike "perfect." NEVER. It is all about how the right hand of the rider feels for where they are and it is not in a booth. "Perfect" is when they have it dialed for a real world environment, not dyno world, and they are standing on the podium.

I think we as ST riders need to look at it the same way.
 

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Discussion Starter #12
Have you told your mechanic about your gas mileage yet?

I know that sound like a stupid question but they can't tell on the dyno what the mileage will be and there is no "perfect" setting with a PCIII or anything else, they can indeed tweek it and still save performance. I believe their are load based settings that can be adjusted, when there is no real load (cruising) at a certain RPM it can give less fuel for example. Makes a huge difference in fuel economy and won't affect anything when you whack open up the throttle because that is a different load triggering more fuel.

Minor adjustments make big differences but the (mechanic) won't know unless you bring it to their attention because they are adjusting from a machine not a mountain twisty road at elevation in the PNW. I find it interesting that people blow off mods to: "add mods and get horrible fuel economy, now live with it." It is so lame. Ultimately, your performance will go up and your economy will go down, that much is not rocket science. I think we have to realize that DYNOS ARE NOT REAL WORLD.. I have all of your mods and am in the over 40 mpg+ range. Took a bunch of tweaking with my Techlusion which adds fuel and is a load based system. I would ride it, adjust it, ride, adjust, many times even after a dyno run. If people are not willing to go through that process after mods, then I think they should save their money.

Next time you are at a racetrack watch how many times they put the bikes on a "dyno" to dial it in to have the bike "perfect." NEVER. It is all about how the right hand of the rider feels for where they are and it is not in a booth. "Perfect" is when they have it dialed for a real world environment, not dyno world, and they are standing on the podium.

I think we as ST riders need to look at it the same way.
I think you've hit the nail on the head J. I just downloaded the Dynojet software for my laptop, saved the map my guy built and am looking into how to tweek it myself based on riding feedback. This is going to be an adventure in tuning ;-) I just need to find out if the PCIII can tune for the lower RPMs, if I need to diddle with the trim, or both.
 

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Mine gets in the low 50s on the highway. If I wring the snot out of it it drops to the mid to upper 40s. Since the cruising rpm is around 5,000 your rich mixture is obviously the killer. Good tuning depends on how you define good and for me the factory setting is a good balance of fuel economy and performance.
 

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I need to talk to the mechanic and see if I can get two maps and change them on my own via the PC-III, one for economy and one for performance.
Or wait for the PC 5 and have 2 maps that you switch between with a handle bar mounted switch! In the mean time, ask your tuner to try leaning out the entire map a couple of percent at a time (the whole map, not a specific rpm/tp) until the power just starts to drop off. Even the very best tuners seem to go just a little bit rich because it is safer for the engine and generally provides better drivability.
 

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Probably a little late to the discussion, but I have been lurking. I just took a *ahem* spirited ride in the country, two-up, with the 2003 ST4S. 46.6 mpg when I filled up 5.1 miles into reserve. So I say anything in the 30's is excessively thirsty. My 4-valver has full Termi's and chip upgrade, so I can't imagine the mileage would be any better than stock.

This was mostly in the 60-80 mph range with a couple of ton-up miles thrown in to get her into top gear.
 

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Discussion Starter #16 (Edited)
Or wait for the PC 5 and have 2 maps that you switch between with a handle bar mounted switch! In the mean time, ask your tuner to try leaning out the entire map a couple of percent at a time (the whole map, not a specific rpm/tp) until the power just starts to drop off. Even the very best tuners seem to go just a little bit rich because it is safer for the engine and generally provides better drivability.
I've contacted the local Ducati shop with the dyno, they're going to take another look at it for me this week. I hope there is a way to restore the efficiency and still get more smootheness out of it then before the PC-III, otherwise this going to be a sucky way to flush $800+ into the bike.
 

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Hey Marty - I was reading this post, and agree that a lot of my MPG issues started with the performance ECU as well. The addition of the Perf. ECU was done while troubleshooting some other issues, so I didn't have the whole Perf. Package. It is at this point I noticed the drop in MPG to 32 ish.

I then switched to an open air box, and new pipes, thinking that it would help the ECU by working as a whole Perf. system. I didn't see a change in MPG, still was in the 32 range. However, I noticed at this point, the bike was so responsive, and really fit me very well.

I then started thinking about a PC-III, but really use that as the way to set my "during the week / long haul" settings; and then turn it off for my weekend zips around the hood with my friends.

I am not sure where your addition of the PC-III fell into the mix. Was it at the same time as your other performance mods? Or did you perform the Ducati Performance changes first, and had everything working well; the THEN you added the PC-III, at which point your MPG dropped to the 32 range.

Thanks for letting me know.
 

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Discussion Starter #18
Hey Marty - I was reading this post, and agree that a lot of my MPG issues started with the performance ECU as well. The addition of the Perf. ECU was done while troubleshooting some other issues, so I didn't have the whole Perf. Package. It is at this point I noticed the drop in MPG to 32 ish.

I then switched to an open air box, and new pipes, thinking that it would help the ECU by working as a whole Perf. system. I didn't see a change in MPG, still was in the 32 range. However, I noticed at this point, the bike was so responsive, and really fit me very well.

I then started thinking about a PC-III, but really use that as the way to set my "during the week / long haul" settings; and then turn it off for my weekend zips around the hood with my friends.

I am not sure where your addition of the PC-III fell into the mix. Was it at the same time as your other performance mods? Or did you perform the Ducati Performance changes first, and had everything working well; the THEN you added the PC-III, at which point your MPG dropped to the 32 range.

Thanks for letting me know.
I had the full DP perf kit installed last fall, the PC-III was recently installed a few weeks ago during the 6K service.
 

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Discussion Starter #19
From the data files I got after tuning it's clear it's running much richer in the 4000-5000 rpm range, and generally richer overall. I'm definitely going to have to talk to my guy and see if there's a middle ground to lean it out some and still retain some of the performance smoothness. The added richness <5000rpms explains why it seems to be sucking the gas down in everyday riding.

I loaded the PowerCommander software to check out the details of the map and found an interesting pattern. In the chart above you see the A/F mixture between 3800-4800 is below 13:1, which curiously is where the map is driving up the injector's duty cycle in the 5-40% throttle position. I think I'm going to try and zero out (or at least cut in half, then half again) and observe the impact on performance vs economy. Weather should be nice this weekend, I can go for a 100 mile ride and set it before I leave, then set it again when I fill up and turn around for the ride home.

 

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Discussion Starter #20
I zero'd out all the cells in 5-40% throttle range from 2000-5000 rpms. I took it for a short spin (20 min) with no popping or rough running noticible. I'll take it for a good 100 mile ride this weekend to see if the mileage improves. I might bring my laptop with me, ride for a couple of hours, top off the tank and zero the whole map, then ride back and compare the performance and mileage overall.
 
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