Vid: 37’s and 4.88’s on highway

[prewdog4]

It says what gear it is next to the “D”

So, I’m curious did this change with the 21 models? My Sport S does not have the gear Number beside the D? Are they all like this for 21?

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[krweatherl]

Nice! Yeah im hoping the new pulsar here in a couple weeks has it all sorted. Livernois is also good. Be curious to see how much of the change you get without the tune just to compare.

I will definitely update in this thread. I’m curious also. Mine has 4200 miles on it so far, my normal around town driving 7-8 miles each way to work has me seeing 13. I’m 56 and tend to never see high rpm or wot.

 

[krweatherl]

So, I’m curious did this change with the 21 models? My Sport S does not have the gear Number beside the D? Are they all like this for 21?

There’s a setting you need to change to see the gear, the stock setting has it disabled.

 

[Jaxmax]

Yes and it is not a programer thing just scroll through setup. I usually run with economy setup on and next to trans gear it is in, is the current MPG, there is an exact same display without the current MPG, and I got that by mistake once and of course I was thinking great here we go.....Jack

 

[Factoid]

Well, Kurt, for another $35k you could keep the 4.10s, do 85 while easily staying in 8th and get 15 mpg while doing it.

I will realize a full pay back on my investment in 2084!

I see your video and raise you one hemi and Ram 8spd video:

 

[prewdog4]

Cool, thanks for the help. When it gets above 20 below I’ll go though the menu and change it.
Will be following this and adding updates also. I’m getting 4.88s this week or next!!

 

[Jaydebe]

That's weird. I've been running 37s since 9k, now at 25k and with molles, tonneau, winch and bumper, I pulled about 19-20 on the hway. Around town 15-16mpg.

I have ZERO mods other than JL Mini Tazer.

As I added a 1/2 H. rack, I lost 1-1.5mpg.
Under load (rack and bikes) 17.5 from WV to Ga.
Through on the RTT and fully loaded, 15.5. WV to Ga.
Cross country trips fully loaded, 13.5 on open roads.

That said, I was very conscious about weight when buying 37s and rims!
What I really wanted was 42lbs per rim, what I settled on was 31lbs and factory is 23lbs.
Tires are similar; I went with Grabber ATx because they are 72lbs and not close to 85lbs like the Nittos I was considering.

just read your post on how to get 20+ mpg on 37s and watched your 5 part primmer. Curious where your mpgs ends up with 4.88s. I installed 37s on my JTR at 415 miles and my best mpg has been 16.5 at 70. Ive long thought that with some minor performance enhancements this thing would be able to hold 8th longer and get much better mpgs. You proved it. I just ordered the Mopar CAI, AFE filter and the AWE Exhaust. Can’t wait to see what gains I get if any. Not sure yet on the Pulsar.

 

[JerseyMike]

That's weird. I've been running 37s since 9k, now at 25k and with molles, tonneau, winch and bumper, I pulled about 19-20 on the hway. Around town 15-16mpg.

I have ZERO mods other than JL Mini Tazer.

As I added a 1/2 H. rack, I lost 1-1.5mpg.
Under load (rack and bikes) 17.5 from WV to Ga.
Through on the RTT and fully loaded, 15.5. WV to Ga.
Cross country trips fully loaded, 13.5 on open roads.

That said, I was very conscious about weight when buying 37s and rims!
What I really wanted was 42lbs per rim, what I settled on was 31lbs and factory is 23lbs.
Tires are similar; I went with Grabber ATx because they are 72lbs and not close to 85lbs like the Nittos I was considering.

Are you sure you set the tire size right?

that makes the biggest difference with gas mileage calculation.....35s are 33.5 mounted and under weight, I imagine 37s are likely around 35.25

 

[KurtP]

^this. Tire size must be calculated from measuring the circumference on the wheel at pressure.

 

[Jaydebe]

Yup, pretty easy.

We do a lot of trips, which is why I have 25k in 8mo. of ownership and would've been closer to 30-33k if I hadn't bought a second car for daily travels.

I reset the tire size all the time depending on how & where I travel because I need my equipment to last.

The Grabbers grow & shrink about 1/3-1/2" when going between 28 - 35psi which can offset the speedo by 2-3mph.

When travelling with a full load, I have to adj. my rear PSI (35) in particular because the tires will otherwise jump to 39-41psi.

I always verify my MPH & miles travelled vs the GPS.
Mostly just to know. Honestly, I'm one to sacrifice mpgs/fuel to take less time travelling, so I'll be heavy on the pedal.

Plus: I will do a few manual calculations at fill ups along the way. The JTR seemed to be pretty dialed, usually less than .2 mpg off (in either direction) from the dash.

FYI Tank range:
- Stock I got about 440 mls per tank at 19-20 gal fill-up.
- 37s and Tazer it dropped to about 390-400 per fill-up.
- Fully loaded 300-320 around 70, 260-270 75-80mph.
- Worst I've gotten is 240 a tank; loaded and pulling a loaded 6x12 at 80 mph.

Are you sure you set the tire size right?

that makes the biggest difference with gas mileage calculation.....35s are 33.5 mounted and under weight, I imagine 37s are likely around 35.25

 

[krweatherl]

Yup, pretty easy.

We do a lot of trips, which is why I have 25k in 8mo. of ownership and would've been closer to 30-33k if I hadn't bought a second car for daily travels.

I reset the tire size all the time depending on how & where I travel because I need my equipment to last.

The Grabbers grow & shrink about 1/3-1/2" when going between 28 - 35psi which can offset the speedo by 2-3mph.

When travelling with a full load, I have to adj. my rear PSI (35) in particular because the tires will otherwise jump to 39-41psi.

I always verify my MPH & miles travelled vs the GPS.
Mostly just to know. Honestly, I'm one to sacrifice mpgs/fuel to take less time travelling, so I'll be heavy on the pedal.

Plus: I will do a few manual calculations at fill ups along the way. The JTR seemed to be pretty dialed, usually less than .2 mpg off (in either direction) from the dash.

FYI Tank range:
- Stock I got about 440 mls per tank at 19-20 gal fill-up.
- 37s and Tazer it dropped to about 390-400 per fill-up.
- Fully loaded 300-320 around 70, 260-270 75-80mph.
- Worst I've gotten is 240 a tank; loaded and pulling a loaded 6x12 at 80 mph.

I’ve never seen anything close to this with my JTR. Installed my SST pro 37s on Black Rhino Armory 17x9.5 at 415 miles and went on a 900 mile trip the next day from Sw Washington to Baker City Oregon and back, nothing out here is flat and most is mountains. Best we got was 16.8 and that was a trip into the mountains on slower back roads. Used a Tazer to get My Speedo calibrated and check it regularly with GPS. I do use Fuelly to track my vehicles and yes I find the dash to be very close to hand calculations. The most I’ve ever gotten out of a tank of fuel is 274 miles and that was 19.3 gal.

 

[Mr. Wuf]

I dropped my Overland (3.73 gears) off at the shop this morning to get 4.88s installed. I suffered long enough with stock gears and 37s. I picked it up about an hour ago, and it’s such a night and day difference. I can’t wait to drive it for a couple hundred miles and see how it affects my mileage.

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