Topic: Cold Air Intake/Throttle Body upgrade=increased MPG??

[Loke Groundrunner]

Since I upgraded to 31" BFG's my MPG has gone from bad to (pretty much) horrible. I've been trying quite diligently to watch my driving habits but it's just not enough. The "daily driver" 4-Banger is kicking my arse at the pump. The extra weight of the hard top, tow bar and full size spare don't help either. I've been eyeing up the following items as a last ditch effort to save a couple of MPG's:

http://airaid.com/310-164_Jeep.asp

http://www.airaid.com/310-511_jeep.asp

I'm hoping the installation of both of these might help increase/maintain decent road perfomance and even save a few bucks at the pump. I realize that any small savings in gas would be offset by the purchase of these mods,..BUT,...in the "long haul" it might be worth it.  Any thoughts appreciated. I'm up for trying anything at this point. I might end up having to pedal the 10-speed to work pretty soon. cheers.

[wrangler387]

Dont bother with the spacer... you might see a small gain in performance with the intake, but no difference at the pump. What kind've mpg are you getting? Have you given the jeep a tune up?

[Jeffy]

Since I upgraded to 31" BFG's my MPG has gone from bad to (pretty much) horrible. I've been trying quite diligently to watch my driving habits but it's just not enough. The "daily driver" 4-Banger is kicking my arse at the pump. The extra weight of the hard top, tow bar and full size spare don't help either. I've been eyeing up the following items as a last ditch effort to save a couple of MPG's:

http://airaid.com/310-164_Jeep.asp

http://www.airaid.com/310-511_jeep.asp

I'm hoping the installation of both of these might help increase/maintain decent road perfomance and even save a few bucks at the pump. I realize that any small savings in gas would be offset by the purchase of these mods,..BUT,...in the "long haul" it might be worth it.  Any thoughts appreciated. I'm up for trying anything at this point. I might end up having to pedal the 10-speed to work pretty soon. cheers.

The first thing you need to do is recalibrate your speedometer.  It will read slow which will throw off all your mileage calculations.

http://4bangerjp.com/forums/index.php?topic=15.0  (I'd probably go with a smooth bore TBS from ebay, they are a fraction of the cost of a AirRaid/Poweraid)  This works well with the 4.0L TB.

As for the CIA.  I'm not sure if you'll see much of a change in mileage.  I know when I went with a K&N filter on a custom CAI, I lost some low-end torque but gained more on the top end.

[chrisfranklin]

The 4banger doesn't get great mileage any way you cut it.  Even with 205 tires, a 5spd, and the engine in perfect tune you are looking at around 18mpg city/20 hwy (maybe get 5-10% better than that using different engine oil or various mods).   

I guess if you were used to certain mileage and then it dropped when you went to larger tires and added a little weight, you're probably ticked now that gas can run you nearly 4.00 a gallon for regular self-serve some places.

If the cost of gas is pain in the tail and you want to hold on to your jeep, then just ebay your bigger wheels/tires and weight-adding mods for more mileage-friendly stuff.  Could also regear (ka-ching) so that your engine was working like it was powering 205s (might be a worthwhile investment if you knew you were going to keep your Jeep 5-10 years). 

The mods might give you a little more power and noise, which might make your driving a little happier - but, they are not going to do what you want at the pump.  Look at the bright side, at least you're not driving the 4.0 I6 in 2007  

[Loke Groundrunner]

Thanks for the replies, gang. I gave the clanger a COMPLETE tune-up and 4-wheel alignment after I had the new tires/wheels installed. I realize that I still need to change the speedo gear, but HAVE checked my speed against local radar checkpoints and it really isn't too far off. My mileage seems to be hovering around 12-13 (and that's being generous and allowing for a little speedometer compensation). Unfortunately nearly all of my current driving is city commuting (averaging around 20 miles daily) and it's hotter than hell where I live. So,..I've got all THAT going for me . I'll probably (at least) give the cold air intake a shot. As far as gas prices are concerned, it's getting pretty ridiculous these days. Hell, even if I drove a Toyota Prius I'd still be annoyed with the price (but I'd have ALOT more time/miles between fill-ups to forget about it). In regards to the tires/wheels, I might have lost a couple of miles per gallon but no more than that. I will say that it DOES handle ALOT better with the 31's than those little Oreos I had  before. I'll have the Jeep paid off within a year so I'll do my best until then (and then decide what to do next). I still enjoy driving the clanger and have a hard time picturing myself behind the wheel of anything else. Oh well.....damn those fossil fuels and torquey 4 cylinder engines!

[chrisfranklin]

I'm 16mpg in the city/subs with stock gearing and smallish 29" tires and a 5spd.  And engine and drivetrain are extremely well-maintained, too.

Loke, you are really not talking me in to inching up to the low "30s"  - 31", 33+" tires - on stock gearing based on what kind of mileage you're getting currently with your TJ.   

Too bad, too.  I don't think Jeeps really look properly proportioned until they are on at least 31s. I look at any stock '03-'06 SWB Rubicon and I (unrealistically) think, "its on 31s and it looks good...every Wrangler should start with 31s."

[Jeffy]

If you want better mileage, I suggest going into teh Mileage thread and asking those who get high mileage, what they're doing.  Although since it's ALL city driving you're doing, you probably won't get really high numbers.

(On the highway, my best mileage was around 26mpg.)

[wrangler387]

I have 31" BFG a/ts and would get 18mpg city with the stock ecu. I rarely get on the highway though because around here you have to maintain atleast 70mph or your getting honked at/yelled at etc... So i just take a regular city roads home 45mph or so...

[chrisfranklin]

(On the highway, my best mileage was around 26mpg.)

GTFOH!?    You had to be coasting downhill in the Rockies or something to get that kind of highway mileage, Jeffy.  Are you talking about when your Jeep was new and on stock tires or something, maybe?

A sustained 26mpg would mean you could get close to 400 miles from a 15 gallon tank, 500-550 miles on a 20-21 gallon tank.   

[Jeffy]

GTFOH!?    You had to be coasting downhill in the Rockies or something to get that kind of highway mileage, Jeffy.  Are you talking about when your Jeep was new and on stock tires or something, maybe?

A sustained 26mpg would mean you could get close to 400 miles from a 15 gallon tank, 500-550 miles on a 20-21 gallon tank.   

This was with a relatively stock Jeep.  32x11.5R15's 3" lift and no other mods really.  This didn't happen every day mind you.  This one repeatable though.  Stretch of highway that was fairly flat except for a bridge crossing that spanned a few miles.  Kept speeds below 65mph.  I think I had a rear seat and tube bumper at the time now that I think about it.  Oh and this was with a 15 gallon tank. (ie., limited to 15 gallons)  The engine was also only a year old.  Regular oil changes done by me.

[Chad]

Perhaps you had a significant tailwind too for 26mpg.  I have a fairly stock tj 31x10.5 and 3.5" susp. lift and i get numbers that look more like Loke Groundrunners- around 13mpg often lower, its terrible, I haven't changed the spark plugs in years though so perhaps that might help does that firepower ignition kit help mpg at all?

[aw12345]

My little 4 popper gets between 19-22mpg depending on city or highway driving. Highway driving over 65 seems to hurt milage. For city driving it will do ab out 19 mpg every time this is with 4" of lift and 31" tires. One of these days I will regear the little beasty though so I got a bit more oomp in 6th. Now you have to go about 75 to get in its powerband.

Art

[Jeffy]

Perhaps you had a significant tailwind too for 26mpg.  I have a fairly stock tj 31x10.5 and 3.5" susp. lift and i get numbers that look more like Loke Groundrunners- around 13mpg often lower, its terrible, I haven't changed the spark plugs in years though so perhaps that might help does that firepower ignition kit help mpg at all?

I don't think I had a tail wind going both ways (ie., round trip).    I posted in the other thread I get 16-18MPG, now.

[Loke Groundrunner]

WELL,...I have been following a VERY STRICT diet of "light RIGHT foot" the past few days and it seems to be helping a little bit. I'm gonna order a new Speedo gear this week and will probably do the mods anyway. I'll keep you posted on the results. I'm gonna try to post a few pics soon as well. cheers and a good old "Jeep Wave" to all of yah.