what have you done that truly increased mileage on your diesel?

VortecJeep

VortecJeep

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Aug 24, 2005
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Concord, NC
My 2005 Cummins is my daily driver and tow rig. I would love to squeeze out some better mileage, as my commute is 23 miles each way.
So what have you diesel guys had success with that truly increased your fuel mileage? I know a lot of products claim they increase mileage, but I am looking for folks that have actually seen true results.
I already drive like a grandpa, so my driving style can't change any more to get any better mileage.
 
On my PSD it was a turbo back 4" exhaust, Cummins is bit of a different animal.
 
Exhaust always helps as well as a good quality programmer even on the high levels my Adrenaline still delivers higher mileage when driven right. For the common rails though about the best one out there is a smarty really hard to beat. Later on a set of good injectors and turbo (sized appropriatly) will deliver mileage when you want and power when you need it.
 
Get rid of the cat, and if you're just in it for mileage, buy a Smarty Junior. I've ran pretty much every chip/programmer possible on a common rail and a Smarty is by far the best in every aspect, including fuel mileage. A cold air doesn't really do a lot for a CR, except for making the turbo more audible.
 
Well... what are you getting now?
 
I'm betting that's about as good as you're going to get.

You could try getting a Smarty with the half power setting, see how that does... but it'll take you a long time to pay for the purchase price with fuel savings.
 
Shawn said:
I'm betting that's about as good as you're going to get.

You could try getting a Smarty with the half power setting, see how that does... but it'll take you a long time to pay for the purchase price with fuel savings.
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I always run the numbers, it would take 40,000 miles to pay for the cheap smarty if it takes me from 17mpg to 18mpg. That's hard to justify.
 
I'd kill to see just 15 mpg. I'm only getting 11.5 at best but w/ the flatbed and weighing in at almost 9500 lbs. I guess that isn't to bad. I also idol it some especially on Mondays when I have the kids and they fall asleep so I have to let the a/c run.

My truck has never had a programmer and as far as Im concerned it never will. Go over to cumminsforum.com and read about all the trouble everyone is having then look at their profile and see what kind of programmer they have.
 
I put a diablo sport power puck on my 03 ccsb 3500 with a 6 speed. it gained me about 1.5 to 2. mpg. I also had a dual 4in straight pipe exhaust and big open air filter. i averaged 21.5mpg mixed driving. the power puck was under 200 bucks and had 3 settings 0-60-90hp. I have an 07 duramax now and only gets 15.5, so i parked it and bought a 95 civic 38mpg!!
 
VortecJeep said:
I always run the numbers, it would take 40,000 miles to pay for the cheap smarty if it takes me from 17mpg to 18mpg. That's hard to justify.
Click to expand...

Not to mention, unless you have a lot of self control...that smarty is going to make your fuel mileage somewhere closer to 15mpg.
 
I gotta 2000 PSD 6 speed 4x4. Super chip, 4 in exhaust and drop in K&N

Typicaly I got 17, I slowed up my driving, skip 2nd and 4th, keep the RPM at 1500 or lower just to stay put of the turbo so much, and I can get mid to upper 18's

Dad had it befor me, said he could get closer to 20 but I have a hard time driving that slow.

I have noticed, after driving like this after a few weeks, you have to "blow the soot out" or it will start to sumble a little.
 
rabb11d said:
I put a diablo sport power puck on my 03 ccsb 3500 with a 6 speed. it gained me about 1.5 to 2. mpg.
Click to expand...

2wd or 4wd? Hand calc'd on the mileage?

If I can keep it to 'state road' highway mileage... no stop and go, no faster than about 60mph, I can get an actual 21mpg out of my 03 4x4 6spd.

Any faster or any more around-town driving, and it's 18-20 highway and 17-18 mixed. But the 555 motor is supposed to be the best for mileage overall... or so I've been told.

It's got a full 4" pipe on it now, but that didn't affect mileage at all.
 
I have a 24 valve in a 2K 2500HD Extended cab. I'm getting about 19.4/19.5 calculated manually over a 350 mile average weekly drive. it has a AFE intake but is otherwise stock. After reading many good things about the Quadzilla milage programmer i decided to spring for one. My milage b4 the programmer over the same 350 mile weekly drive was averageing 19.8/19.9 mpg. needless to say i'm not impressed. all milage corrected for tire size.
Sure would like to squeeze 21/22 out of it.
 
on my '99 Cummins 24v:
aFe stage II CAI (dry filter)
TST Boost elbow
Quad Adrenaline w/Pulse V2
Turbo back Rollin Smoke Diesel 5" exhaust (straight)
DTT built Trans
32.7" tires
3.55 gears

I've seen highway numbers as high as 21mpg and city numbers right around 19mpg...of course this is staying out of the boost as much as possible, doing a test now to see how high I can actually get my numbers running level 7 on a custom tune around town and running the "max mileage" tune once up to speed on the hwy...I'll let cha know what I find...future plans for mileage mods is the Spyntec hub conversion, electric fan and a good set of injectors
 
Shawn said:
2wd or 4wd? Hand calc'd on the mileage?

If I can keep it to 'state road' highway mileage... no stop and go, no faster than about 60mph, I can get an actual 21mpg out of my 03 4x4 6spd.

Any faster or any more around-town driving, and it's 18-20 highway and 17-18 mixed. But the 555 motor is supposed to be the best for mileage overall... or so I've been told.

It's got a full 4" pipe on it now, but that didn't affect mileage at all.
Click to expand...


It was 4x4 with 33in tires(speedo corrected), 3.73 gears, i shifted pretty early and never ran over 70. I can't rememeber if i hand calculated it, that was a couple of years ago when i had it. I still have power puck if anyone wants it. $75.00.
 
I have a 99 ram 2500. S&b cai 4" diamond eye exhaust, super chip flashpaq, airdog 100 and banks high ram manifold. With 4.10 gears and the cruise set at 70 on my commute I average 22. Stock I only got 17.
 
My milage seems to go down hill by about 5 or 6 MPG when I took the comp box off....due to a lack of self control and not wanting to destroy my auto

But....The best thing I did for MPGs....was buying a motorcycle.
 
04 cummins 24v with a 4in catback and edge juice with attitude programmer sitting on 35's and i'm getting 17-19 mixed depending how heavy the foot gets and 24-26 highway. i towed my cj 5 from wake forest to norfolk,va yesterday and averaged 19.6 mpg the whole way.
 
Since its a diesel...I've found a few things that really help in my TDI Passat:
1. Warm motor. I get significantly better mileage in the summer. A block heater helps get it up to temp in the winter.
2. Shifting into the next gear as soon as reasonably possible without lugging. My car has a tiptronic (shiftable auto), so I am bumping it into the next gear way before the auto would normally shift.
3. Coasting downhill. I pop it into neutral when going downhill. That allows the revs to drop from 2000 or whatever, down to 700rpm.
4. Timing redlights. If its red, try to slow down as little as possible by slowing down early so that you can maintain speed. I try to keep over 40mph, as that is when my car will stay in 5th gear comfortably. Likewise, if its green, give a little juice to make sure you make it.
5. Drive the speed limit. This is the one I struggle with the most. I like to make progress. The most efficient speed for my car I've found to be 52-55mph. I typically run 10-20mph over depending on traffic, and average 40ish mpg. For a couple of weeks, I ran the speed limit on the interstate on my way to work, and manage to get over 50mpg almost every time. However, It took 6 minutes longer to go the 30 miles, and my patience didn't last, and 40mpg was still great.
6. Use the windows instead of the AC. On a big truck diesel it probably doesn't make as much difference, but on my 2.0L it helps noticeably.
7. TIRE PRESSURE! Keep it high. It decreases rolling resistance and makes them effectively bigger diameter, without costing any torque loss.

Thats all I can think of. Hope it helps somebody, it sure made a difference in my diesel.
 
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