Hello,
I have an 87 montero that I just got back up and running after a bit of work. The only problem I have now is the tires. Im looking to be able to drive highway and city, as well as trails. Right now I have 31's on it. The rest of the drivetrain is stock. The car is getting bad mileage, 10mpg, and wont hardly go over 60. I know the cat converter needs to be replaced, but I think that the large tires are messing with it as well. With stock tires, other than hardcore offroading, should it be ok? Also, will this help with it on the highway? Thanks,
Sean

 

That much mileage loss is due to something else not simply a tire size change. The stock size is a 29" tire. I run 33x12.5x15 MT's and I get that kind of mileage w/ my 3.0L v6 but I know others with a 2.6L engine that get much better mileage than you (15mpg IIRC) w/ 32's.

I'd check your carb's vacuum lines to ensure they're working properly. Also replace your Cat as you suspect since it will reduce your power and mileage.

HTH.

 

Thanks for the heads up.

 

Got your PM's. As for checking your carb out. Even an experienced carb mechanic may shudder when they see how complex the Mikuni is. If he has experience with Mikuni carbs then you're ok but if his experience is limited to Holley or Weber carb's then you may want to give him a head's up on what he'll be working on. At a minimum I'd check where the carb's hoses currently are. Take pictures... lots of pictures of your current setup. At least you'll be able to get it back to it's original configuration if they can't figure it out.

HTH.

 

Mileage -
My 94 Hyundai Galloper (94-95 Mitsu Montero LS) 3.0 12 valve V6 gets10-11 mpg around town. On the highway it gets about 15 or 16 mpg. I'm running 265/70 R15 tires. I installed new plugs and wires, and cleaned the throttle body.

I think the Montero just gets crappy mileage. [:'(]

...and I'm going to put on 31x10.5 tires anyway. Maybe even Bridgestone M/T if I can get a decent price.

 

My 95 LS gets 17-19mpg on mostly highway driving. It is a 24valve 3L SOHC engine. On the older Mitsus there was of course, some with 4cyl engines and some with V6's. Even when properly tuned, it seems that the V6 versions got better mpg than the 4Cyl models. The 4Cyl engine is just not as efficient as the 6cyl engine.