Cracked 22mpg combined

[04liberty4x4]

Hey guys, just thought I'd give an update on my quest for MPG in my wife's jeep.


We had 2 tanks of 20.4-20.6 and finally this tank we recorded a 22.1 MPG combined. She drives 50% city/ 50% highway. We are damned pleased, according my my scangauge we are averaging 26-27 mpg on the highway.

Mods we did:

Cold air intake
fully synthetic oil
50psi in all tires, tires brand new
not idling in prolonged periods while waiting at stoplights

 

[SDLiberty]

Hey guys, just thought I'd give an update on my quest for MPG in my wife's jeep.


We had 2 tanks of 20.4-20.6 and finally this tank we recorded a 22.1 MPG combined. She drives 50% city/ 50% highway. We are damned pleased, according my my scangauge we are averaging 26-27 mpg on the highway.

Mods we did:

Cold air intake
fully synthetic oil
50psi in all tires, tires brand new
not idling in prolonged periods while waiting at stoplights

Which C/A intake do you have? Are you running Royel Purple?

 

[VTNomad]

Psi

PSI seems high, does it exceed the maximum recommended PSI for your tires? If so, you might get unusual wear patterns that will decrease the life of your tires. It would also reduce traction, which could be dangerous.

 

[BjBnet]

wow, they'll pop on the first curb you rub LOL
I think there must be something else you're not telling us ;-) j/k

 

[jnaut]

Mods we did:

Cold air intake
fully synthetic oil
50psi in all tires, tires brand new
not idling in prolonged periods while waiting at stoplights

Impressive to get over 22 combined. As I've stated in previous threads, my mileage is almost spot on to the EPA numbers. Are you driving a CRD?

Oh, and 50psi? I'd be real nervous about a blowout at highway speeds. What's the recommended PSI for that tire you're riding on?

 

[JeepJeepster]

Agreed on the psi. Anything that is close to the max tire pressure is dangerous. Max pressure on my yoko's is 51psi and I would never get without 10psi of that. I usually run around 36psi and my tires run evenly.

Not idling and the tire pressure probably helped out the most. If you shut the Jeep off a lot at stop lights its going to be hard to stay ahead with the price of tires(psi to high) and the cost of a new starter.

 

[04liberty4x4]

Tires are rated for 51 psi.

As for all the uneven tire wear BS, I've got a pair of tires on my accord with 87K on them rated for 60K. They are rated for 44 psi and have been at 60 psi for 4 years with no uneven wear.

Burst pressures on modern tires are well over 200 psi, you have been repeating too many myths which are not true. Low tire pressure leads to fatigue and blowouts, NOT high pressure.


I'm driving a 2004 Liberty 4x4 gas engine.

 

[VTNomad]

Psi

I keep mine at 34 PSI. It's the only PSI I can run where I don't get a low pressure alarm in the morning, and a high pressure alarm in the afternoon.

 

[jsc7002]

Im running my 245/75's on 53 psi I had them at 62 psi at one point but they are rated for 80 psi max

 

[2003KJ]

33-35psi for me, and routinely pull down 20mpg give or take .5.....I do about 80 miles round trip on the highway each day...the rest is on country back roads..so the stop and go is really at a minimum.

Nothin fancy....regular size tires, tune up about 30K ago, run M1 Synthetic since about 10K.

 

[Dave]

33-35psi for me, and routinely pull down 20mpg give or take .5.....I do about 80 miles round trip on the highway each day...the rest is on country back roads..so the stop and go is really at a minimum.

Nothin fancy....regular size tires, tune up about 30K ago, run M1 Synthetic since about 10K.

Tim, pretty much the same here. I am running 36psi in my a/t's-a little more than you. I tried 38psi and the ride got too stiff for me although it looked like I still had a safe footprint.

OP......what brand and size tires are you putting that 50psi in.

Dave

 

[tan's2002kjlimited]

I'm running 45 psi (max 50) on a set of Silent Armors.

 

[icarl]

I keep mine at 34 PSI. It's the only PSI I can run where I don't get a low pressure alarm in the morning, and a high pressure alarm in the afternoon.

rollinglaugh.gifhah.gif

 

[2003KJ]

Tim, pretty much the same here. I am running 36psi in my a/t's-a little more than you. I tried 38psi and the ride got too stiff for me although it looked like I still had a safe footprint.

In the summer months I usually keep it around 33-35....in the winter when it gets real cold and the pressures tend to drop off quite a bit, i'll bump it up to about 37 or so depending on just how cold it gets.

Winter MPG's go down to around 18-19 highway thanks to all that crap they put in the gas for the winter months, along with extended idle's of 5-10 minutes from warming it up before I leave every morning.

 

[ThunderbirdJunkie]

Tires are rated for 51 psi.
As for all the uneven tire wear BS, I've got a pair of tires on my accord with 87K on them rated for 60K. They are rated for 44 psi and have been at 60 psi for 4 years with no uneven wear.

I'm gonna raise the BS flag on this one.

Those centers are worn out. I don't care what you say...I need documented proof of the mileage, and pictures of the tires with a tread depth gage inserted (and I won't even believe that) before I'll believe ANYTHING like that. What tires ARE they?

Low tire pressure leads to fatigue and blowouts, NOT high pressure.

Yes and no. There is a load index on your tire. If operated AT or ABOVE the stated pressure max, with close to max load, you are susceptible to tire failure.

I'm hoping you live nowhere near me, because it makes me nervous knowing people like you that actually think they know what they're doing and are willingly and knowingly disregarding safety precautions on their vehicle that gets driven on public roads.

Blowouts are also caused by lots of other things, other than underinflation. Like being a person lacking in a sense of social responsibility.

Please stay off the road.

 

[04liberty4x4]

I'm gonna raise the BS flag on this one.

Those centers are worn out. I don't care what you say...I need documented proof of the mileage, and pictures of the tires with a tread depth gage inserted (and I won't even believe that) before I'll believe ANYTHING like that. What tires ARE they?



Yes and no. There is a load index on your tire. If operated AT or ABOVE the stated pressure max, with close to max load, you are susceptible to tire failure.

I'm hoping you live nowhere near me, because it makes me nervous knowing people like you that actually think they know what they're doing and are willingly and knowingly disregarding safety precautions on their vehicle that gets driven on public roads.

Blowouts are also caused by lots of other things, other than underinflation. Like being a person lacking in a sense of social responsibility.

Please stay off the road.

Right. People like me? Oh you mean Educated beings, aka a Tire Engineer. I've been an Engineer since 1976, what the **** have you done?

We put warnings on tires for idiots like you, obviously they are needed.

If you seriously think tires will self implode at the side wall max, or even OVER IT, you sir, are an IDIOT.

 

[yellocoyote]

I don't know if they do it the same way with every load rating (tires included), but when I used to work for the company that made various overhead lifting apparatus (apparati?), the capacity that the slings and such were rated at were only at half of what the true breaking strength (ie: rated at 5000 lbs, break at 10,000 lbs).

Knowing this kind of information makes me a little more apt to push the envelope on rated capacities a little sometimes. For argument sake, if its the same with tires, in theory he could run his 51 max psi tires at/close to 102 psi (or whatever multiple it's rated by) before risking blowout. The ratings on things are set so low to accommodate for manufacture flaws and human error, among many other things.

Not saying that it's a safe practice to run anything over what the item is rated for... I wouldn't do it if it were me. I run my 80 psi rated tires at 40, typically.

Just a thought...

 

[Dave]

I don't know how if they do it the same way with every load rating (tires included), but when I used to work for the company that made various overhead lifting apparatus (apparati?), the capacity that the slings and such were rated at were only at half of what the true breaking strength (ie: rated at 5000 lbs, break at 10,000 lbs).

Knowing this kind of information makes me a little more apt to push the envelope on rated capacities a little sometimes. For argument sake, if its the same with tires, in theory he could run his 51 max psi tires at/close to 102 psi (or whatever multiple it's rated by) before risking blowout. The ratings on things are set so low to accommodate for manufacture flaws and human error, among many other things.

Not saying that it's a safe practice to run anything over what the item is rated for... I wouldn't do it if it were me. I run my 80 psi rated tires at 40, typically.

Just a thought...

good thought....

Dave

 

[04liberty4x4]

I don't know if they do it the same way with every load rating (tires included), but when I used to work for the company that made various overhead lifting apparatus (apparati?), the capacity that the slings and such were rated at were only at half of what the true breaking strength (ie: rated at 5000 lbs, break at 10,000 lbs).

Knowing this kind of information makes me a little more apt to push the envelope on rated capacities a little sometimes. For argument sake, if its the same with tires, in theory he could run his 51 max psi tires at/close to 102 psi (or whatever multiple it's rated by) before risking blowout. The ratings on things are set so low to accommodate for manufacture flaws and human error, among many other things.

Not saying that it's a safe practice to run anything over what the item is rated for... I wouldn't do it if it were me. I run my 80 psi rated tires at 40, typically.

Just a thought...

Holy hell, someone who acutally knows something about load rating equipment.


WELL DONE SIR SHOCKED.gif


You can run your tires EASILY over 2x the "max rating" , but I'm not telling you to do it, nor would the company I work for. Liabilities are a *****.

 

[tommudd]

all the years working for and selling/ mounting Goodyear , BFG, Firestone, Cooper well most any name brand out there, including everything from wheel barrow tires to Semi/ Road Graders/ earth movers etc and this post has become the most wasted use of info so far. Maybe some would like to see my buddys side of his head after a new tire blew off the rim due to him not watching the air gauge...and no it was not even over 100 lb

oh well engineers they know it all I guess

Oh an I was in the tire business before you became an engineer it looks like