Based on my experience with 3.73s in a Ram on 35s with the 5.9 Cummins (still turning too fast on freeway), I feel the 3.55s are absolutely essential to make a 5.9 swap into an 80 feasible. With 3.55s, A343F OD of .753 and 34.5” tires, 75 mph rpm would be an ideal 1950 rpm.
I live in the rural west and have to travel on 80 mph freeway to get anywhere from my house.
The image below is from R2.8 repower gear calculator, I put in the numbers from my truck with 0.79 OD.
It says the R2.8 prefers 1500-2000 rpm. That was definitely true of the 5.9! It purred at...
@PurpleFJ62 - Are you using stock ratios in the HF151? I hear that there’s a taller OD available (Terrain Tamer?).
When I looked at HDJ80s, I was disappointed with the overdrive ratio of the 5 speed.
I had an 05 Ram with the 5.9 Cummins and 6 speed manual with a 0.79 OD and 3.73 axle ratio...
@Delta VS - You’ve done great things for 80 suspension geometry with rear track bar mount and radius arms (both of which I have), it’s time to step up with a high steer correction for the 80! :clap:
Ideally it would move the tie rod to the front, allowing for the use of 9.5” LC 3rd (my biggest...
https://www.ruffstuffspecialties.com/catalog/R2149.html
These were actually produced, but currently shown as out of stock. I like the CONCEPT of the Front Range knuckles better, allowing larger brakes and ABS retention. Keep bugging them hoping to get them produced.
Not as of 4/12/19! I have been emailing and calling them for 2 years. That project is still on the back burner for them.
It took me 3 months and several calls to get knuckle and hub studs and tie rod and drag link from them. Even then, the tap was bad on drag link, I sent it back and got on...
I discovered the hard way that the 200 mpg is WAY more sensitive to mods than the 80. I.e. bumpers and tires affect 200 mpg more than 80, which makes sense as 200 mileage gains came from aerodynamics.
You’re right, I figure I am looking for 3.0 diesel. I keep hoping a shop will figure out how to make the EcoDiesel and tranny ecu and harness run stand alone as is commonly done for LS. So far, haven’t found anyone doing it.
Banks sells their version of the 3.0 EcoDiesel for (cough, cough)...
I have a 4000 lb travel trailer. The 80 chassis handles the weight very well but the 1FZ struggles with the western US trifecta of elevation, grade, and high speed limits, throw a headwind in the mix and I get 4.5 mpg coming out of Moab, struggling to hold 50 mph on 2 lane highway clogging...