So I just found out that the local supplier here in Oregon (SeQuential), that supplies fuel to the Shell station I usually go to, has a cetane rating of 55.3 for their B100. They cut it with regular #2 diesel to make it B20. The cetane rating should then be about 50 for the B20. All the research that I've done states that B20 should be right about there. My question is, what timing would be the best for this 50 cetane fuel? I normally drive at 60-65 and my rpms are ~1550-1675. Should I be around 16* cruise timing for max fuel economy with this fuel or is that too low/high?

South,

 

Since you have the 6 speed, I am pretty sure you have the dana 80 not a hybrid (70U) like the automatics got.  Double check it.  All the manual transmissioned cummins that I have seen that had the correct rear axle, have the dana 80.

 

Hag

3 hours ago, Haggar said:

South,

 

Since you have the 6 speed, I am pretty sure you have the dana 80 not a hybrid (70U) like the automatics got.  Double check it.  All the manual transmissioned cummins that I have seen that had the correct rear axle, have the dana 80.

 

Hag

Mine is m80 same pumpkin like 80 but has d70 hubs

13 hours ago, Southpole560 said:

Does it go up for you if you drive a bit slower?

 

Back in my days of the Edge Comp I use to get 23 to 24 MPG as long as you did 55 MPH as a top speed. This is because the timing will drop sharply after 20% engine load. Edge products basically just add timing on top of the ECM software. 

 

Quadzilla doesn't use the ECM timing table at all. Quadzilla is completely standalone timing while moving under load. As long as you can tune to the peak for the drive style it should improve the MPG. This is all based on how much drag and road speeds your requesting. If your conservative in speeds you can typically push an extra 1 MPG more. 

Edited March 9, 20205 yr by Mopar1973Man

Lot of good stuff here, but has anyone done anything with 215-235 85R 16 tires that us dually's have?

truck currently has 235s on it, but am thinking of going back to the factory 215.

Well I thought I could get 285/65R17 but the tire shop had a good point and said that if I had a blow out or something happened with the tire that it would be difficult to get that tire anywhere since it is uncommon. Should I still get that tire or just make a compromise and go with a 285/70R17? I'm looking to get a small boost in fuel economy.

18 hours ago, Southpole560 said:

Any opinions?

I have put 40k mostly highway miles on my G015 tires and have lots of tread left.  They do fine on wet pasture without tearing up everything, though 4WD is key on hills with no weight in the bed.

I'd buy them again, but would like to try an American brand like Cooper next time.  They own Mickey Thompson.

1 hour ago, Southpole560 said:

Well I thought I could get 285/65R17 but the tire shop had a good point and said that if I had a blow out or something happened with the tire that it would be difficult to get that tire anywhere since it is uncommon. Should I still get that tire or just make a compromise and go with a 285/70R17? I'm looking to get a small boost in fuel economy.

What's your gear ratio. 285 is a good looking tire, I decided to try 265 for next few years.

1 hour ago, LorenS said:

I have put 40k mostly highway miles on my G015 tires and have lots of tread left.  They do fine on wet pasture without tearing up everything, though 4WD is key on hills with no weight in the bed.

I'd buy them again, but would like to try an American brand like Cooper next time.  They own Mickey Thompson.

Do you have any pictures of those tires on your truck? I just don't want the 285/65R17 or 285/70R17 to look funny on my truck since the rims are a slight negative offset. I'm just thinking if I should sway towards the 65 since tire blow outs don't really happen that often and I still have my spare that I might be able to use for an emergency. Even though the spare is small, I still should be able to use it in a dire emergency without damage to the diff right?

31 minutes ago, Dieselfuture said:

What's your gear ratio. 285 is a good looking tire, I decided to try 265 for next few years.

3.54. yea I think the 285/70R17 would look decent, I just don't know how a 285/65R17 would look like on a slightly negative offset rim. I just don't want it looking bad either lol.

Edited March 10, 20205 yr by Southpole560

@Southpole560 buy another wheel to match whats on the truck, 5 tires and start doing a 5 tire rotation schedule. Thats what i plan on doing if i can ever get my wheels finished.

7 hours ago, Southpole560 said:

Even though the spare is small, I still should be able to use it in a dire emergency without damage to the diff right?

If you have open difs, 

8 hours ago, Southpole560 said:

Do you have any pictures of those tires on your truck?

I do, but don't have super wide wheels nor 285s. The tires on my truck when I bought it were 285s, but I knew I wanted to shorten it some for the same mileage reasons, and for climbing in since I still have not found or made running boards, steps, rails, or bars that I like and only have a 32" inseam!

 

I'll try to remember to post them from my computer.

Edited March 10, 20205 yr by LorenS

Remember it take 2 inch of tire size increase to make 1 inch of lift at the axles. Just show you size up and size down...

 

Just with 285's vs 265's (stock) you'll change the final ratio to 3.42:1 (added drag) then only gain 0.6 inches of axle lift (added little frontal area and drag) Then your adding almost an extra 10 pounds of rotational mass per tire in steel belt (added drag). Then since the wider face and most over sized tire are aggressive tread you just added more rolling resistance (added drag).

 

Just 245's (stock) vs 265's (stock) you'll change the final ratio to 3.69:1 (reduced drag) then only lose 0.55 inches of axle lift (reducing little frontal area and drag) Then your almost reduce about 10 pounds of rotational mass per tire in steel belt (reduced drag). Then since the narrower face and most stock tires come in A/T or road tread you just reduced rolling resistance (reduced drag).

15 hours ago, Scarecrow said:

Lot of good stuff here, but has anyone done anything with 215-235 85R 16 tires that us dually's have?

truck currently has 235s on it, but am thinking of going back to the factory 215.

 

I've ran 215's and 235's on my 1996 Dodge Ram 1500 no issues. The 215's gained me roughly 2 MPG vs 235's I took off. Reduced the final ratio to 3.70:1 gain MPG even on a little 5.9L V8 gasser. 

 

Then I've ran 265's, then 235's on my 2002 Cummins for many years. Then switch to 245's gain MPG even at 80 MPH which produced 21 MPG twisting 2,500 RPM's. Reduced the final ratio 3.69:1.

 

Both truck are 3.55 axles.

 

Little trick...

 

235/85 R16 and 265/75 R16 are the same height. 31.7" vs. 31.6".

 

215/85 R16 and 245/75 R16 are the same height. 30.5" vs 30.4".

 

Another tip. It takes 2 inches of tire size to to change 1 inch of axle height. Always laughed about people saying they need oversize tires for axle clearance, but when you compare axle heights not that big of difference. 

 

 

Edited March 10, 20205 yr by Mopar1973Man

Every 0.59" is appreciated when trying to climb in the truck!
I just looked at the Cooper website, and going to 245/75/17s will take me down 1/10th of an inch and loses 2 pounds per tire while narrowing the tread 3/4 and resulting resistance.  Going to the 245/70/17 would take me down 1.1" and shave 6 pounds off of each tire, but it loses 195 pounds of capacity (3195 vs. 3000) per tire, for anyone that cares.

Since my truck doesn't run like a Cheetah on cocaine or even caffeine, I need it to as least look a little cooler with the 1.1" taller tire! May go with the 245/75 tires next time.

I like the idea of re-gearing from 3.54 to 4.10. If someone could make a step by step article together for the D60 and D70 I'll get started. Anybody? 

 

I rebuilt my own trans with no issues, but I'm afraid of diffs. 

Edited March 10, 20205 yr by kzimmer
Spelling

20 hours ago, LorenS said:

I need it to as least look a little cooler with the 1.1" taller tire! 

 

I can say when your doing long haul like I was even just shaving off 1 to 2 cents per mile made a huge saving in fuel when you figured 1.000 miles a week. That roughly 10 to 20 dollars per week or 40 to 80 dollar a month off the fuel bill. Currently I'm right at 16 cents a mile for my truck.

 

Cool doesn't even enter my brain at all. Personally, I don't care if it looks cool, for my truck. When you been on a tight budget and still am you look for every way to keep funds in your wallet than pouring them in a fuel tank, just because it looks cool. I looked at the ratio it produces and the RPM's and which the cruise state for 65 MPH lands since that is common speed for my state. Then figure land, terrain, etc. Lower gearing reduces engine load (another savings). 

 

Still to this day I'm still making a circle track to Boise and back for medical appointments, picking parts, and going just food shopping. 

 

 

Edited March 11, 20205 yr by Mopar1973Man