MPG with late Gen 2 Montero + larger tires?

[monkey620]

Eurosonic, have you regeared your speedometer to adjust for the 35's or is that 15-16 by factory speedo and odometer settings? What kind of driving mostly? Thanks a lot

 

[Jay Ayala]

You know, I'm kind of in the same boat. I have less than 10k on my overhauled 3.0L Gen I SWB. I took a 500 mile round trip for thanksgiving and only got 11.3 MPG on 33" tires all highway miles. I have NOT re-geared my speedometer, and used regular gasoline.

I've decided to start using premium instead and document the results later. By the way. I discovered a cool MPG app for my smart phone. What about you guys? Is anyone else using a clever app?


1989 Dodge Raider 3.0L
1997 Mitsubishi Montero 3.5L

 

[jeep-N-montero]

Here is a free tip, make sure your tire pressure is between the recommended 32-35 psi.

 

[Toasty]

15-16 avg here. Armored, 35s, regeared, free locking hubs.

I get the same with mine, 35's and 4.90 being the correction from 4.27 roughly. So that's accurate and realistic

 

[blackohio]

I know mines a 2.5 but I just did 240 miles on $50/gas at $3.32/gallon with essentially 32x10.5. 16.5mpg split city/highway. No re-gearing.

 

[mapper]

I'm still in the experimentation phase but... My motor runs better/has more zip on premium but my economy is the same, or maybe even decreased on premium....YMMV.

If your O2s are that old, I'd replace them. Old O2s can be used without any significant issues, but I've always seen results when I, frequently belatedly, replace them. Again, YMMV.

 

[quailchaser]

I think the statement that the 98 Montys need premium is not entirely correct. I think the SOHC engines can run regular. The older DOHC need premium and make a litlle more power. Someone correct me if I'm wrong.
Frank in AZ

 

[nwoods]

I've never run anything but 87 octane in mine
Edit: Sorry! Wrote 91, meant 87. Fixed now

 

[snare]

On the 4,605 mile trip we just got back from we got 16-17 mpg regularly, except for when we put Conoco 86 octane fuel in it.

Every time we did that we got 20 mpg.

This is a 98 Montero, 31 x 10.5 tires, Speed is dead on (confirmed with GPS ) Roof rack and limb risers.

I flew to Tucson (from NC) to pick it up. On the drive back and for the first couple months I got 24 mpg highway and 20-22 around town.