txfan

I'm going to buy my new FX4 today and within a week I will be stepping up to 305/55/20 trail grapplers. After increasing your tire size and losing the 1-2 MPG's is there any upgrade you can add to get some of your fuel efficiency back? I was talking to a friend and he claimed after he got larger tires he added an exhaust to negate the MPG loss. His claim was that the engine has to work harder to turn the larger tires. So he added the exhaust for more air flow. I guess his theory adds up, but I thought I would ask the pro's. Thanks in advance.

03Scott

iTrader: (1)

Unless your doing a custom exhaust, most cat backs don't do ****. They just add sound. I just had my flow master exhaust riped out at the beginning of the season and had mineke do a custom y and 3" single back and it didn't do a whole lot for the MPG but it did a little power. It costed me the same for the custom single stainless steel system as a magnaflow stainless steel system sitting in a box. The aluminized systems only last a few years so do it right the first time and you won't have to worry about it. I can get any where from 10mpgs towing to 20mpgs on a flat rd and I have the 5.4 motor.

txfan

Oh ok. Thank you for your honesty. I don't know much about these things other than exausts do add a lot of sound. Thanks again.

SJP

What gears will you have?

txfan

Sorry to bring up an old thread, but I just ordered my 33X12.5 Toyo MT's today! I have 3.73's. Are the tuners helping out with fuel economy?

Franchi Motorsports

iTrader: (9)

A tune will help out 1-2 mpg on freeway at a STEADY consistent pace under 65 but wont help much on city. Most people honestly see worse mpg after putting a tune on cause they cant keep their foot out of it.

txfan

I know it sounds silly, but I watch my MPG like a hawk. And I rarely accelerate aggressively. I'm still having a mental battle with myself about losing that much efficiency. Honestly I probably just need to suck it up and realize I just added quite a bit more rotating mass to a brick on wheels. Haha. Thank you for your reply though. That's good to know.

Franchi Motorsports

iTrader: (9)

Aye, it's not just the size but mostly the rotational mass and weight that knocks it down. Ive been in the same debate myself with my 12 XLT and finally just decided to keep my tires and rims stock sized. I like the looks of larger setups but I already have a fun car, I need to keep the truck practical as possible. lol

txfan

I hear what your saying. My thing is we have an 03 Toyota 4runner V8 that averages around 17 or so. Then we added the new truck which averaged around 16-16.5 and will soon average 14 or so. So we have two gas drinking daily drivers. haha. But we actually decided to get rid of the 4runner and buy her a little lexus IS250 to drive. They get close to 30 mpg on the highway. So I'm not very worried about our gas bill anymore. I still may look into a tuner to help out on the highway. I probably drive on the highway 75% of the time.

BobbyC

iTrader: (1)

The tuner is worth getting for the overall drivability. I did see, as Franchi said, about 1-2 mpg better on the highway.

I have 33" BFG AT/KO and adjusting the tire size helped shift point and just felt better driving in all conditions.

I'd recommend a tuner (I have the Edge) for anyone.