Improve Gas MPG...?

[hps4evr]

it looks like most mpg comments have been made allready. there isnt much you can do with a jeep. they are what they are. i did the intake, electric fan, ditched the cat con and opened the exhaust. these 3 things helped the engine breath easier and with less load. did i get better mileage? maybe, not sure, i was too busy keeping the pedal to the floor cause it sounded cool. i did try to vary my driving habits to see if there was a change. and in the end i i couldnt tell. from hard city driving to highway cruising on o/d. i still managed the same from every tank.
the best you can do is keep your vehicle running tip top. the mileage you get is what you get. be happy.

[parabs]

You are confusing a boosted jeep with a properly geared one.

A 4 litre that is geared properly and isnt constantly shifted an lug will perform more efficiently resulting in better milage.

A boosted jeep just has the potential to use more fuel, and it will.

You can make minor improvements to 4 litre efficiency but its all starts internally. Until you get into cam profiles, and some head work, the rest is just bullshit.

Once you have the breathing efficiency increased, some add ons like a larger TB and headers will continue to help but still, with all that said and done, you are into 3000$ for 2-4mpg...........................................

Like I said, mod becaues you want to. Dont do it for milage.

Goes back to hub swapping for milage. 2000$ hub kit for half a mile per gallon. There's a 10 plus year payout

I have seen people add a blower and increase mileage.  Of course they can burn more fuel at a given moment, but the engines work significantly less overall.

These jeeps are not going to be a 35mpg vehicle, however 2-4mpg is nothing to scoff at when you are getting 15.

-=edit=-

I think you are minimizing the effect that elevation has on performance. 

[Bnine]

You can't control elavation. It has no relevance here.

Anyone familiar with FA knows that the less boost you use, the better your milage.

Lots of jeeps have been charged. They don't get better milage. They slight increase in efficieny gets spent in parasitic loss from driving the blower. The rest of the milage goes out the window using the 36lb/hr injectors because not many people spend 7 thousand dollars on a super charger with better milage at the forefront of their mind.

This bullshit has been beaten to death on every jeep board in existance

In the end its always the same. A bunch of nerds try to desk top mechanic/engineer 25 mpg out of a 4.0, while experienced users tell them not to bother worrying about it.

[Joel]

A bunch of nerds try to desk top mechanic/engineer 25 mpg out of a 4.0, while experienced users tell them not to bother worrying about it.

So which is you......must be Tuesday.   

[Bnine]

The angry version of both of course.................


duh ,,i,,

[w squared]

Everyone knows that you can't get 25 MPG out of a 4 liter unless you're adding Zinc to your fuel.

[Justink]

I'm gettin 18 mpg with a cherokee with a 4.5'' lift, 31 bfg a/t's and a 5 speed (stock gearing) As far as I am concerned, I am doing pretty good ( especially since my right foot is a little heavy  )  Only mods done to motor are cold air intake, and ripped out cat with free flowing exhaust

[parabs]

You can't control elavation. It has no relevance here.

Anyone familiar with FA knows that the less boost you use, the better your milage.

Lots of jeeps have been charged. They don't get better milage. They slight increase in efficieny gets spent in parasitic loss from driving the blower. The rest of the milage goes out the window using the 36lb/hr injectors because not many people spend 7 thousand dollars on a super charger with better milage at the forefront of their mind.

This bullshit has been beaten to death on every jeep board in existance

In the end its always the same. A bunch of nerds try to desk top mechanic/engineer 25 mpg out of a 4.0, while experienced users tell them not to bother worrying about it.

Im not looking to argue but have to point out youre statements are made with broad strokes.

elevation has relevance since we all live in it, and it robs people of the power it takes to move these 4000 lb lumps down the road.

Driving a blower robs power, turbos run on exhaust gas.  The size of a turbo and impeller blade can be made to work on "low revving engines".  36lb injectors do not burn more fuel, they allow for more fuel to be used.  If you have 36lb injectors running down the highway at zero boost you are not putting any more fuel through the system.

I put upwards of 100k on per year on a normal year using my personal vehicle for work.  2-3mpg helps a lot as I pay for my own fuel.  A guy I work with has a 08 tacoma v6, he picked up 4mpg by installing the TRD blower and driving it for the purpose of maximizing the mileage.  I saw it with my own eyes.  Adding a "power adder" works.  You can choose to believe this or disregard it, but it is not bullshit.

[Bnine]

You can't change the elevation where you live, so bothering to mention it is pointless.

We all know what air density does to power but it is still irrelevant for a couple reasons. Aside from the one I just described, people in lower elevations report the same milage we do. They just don't have the power issues that we do.

You can not compare a TRD engine to a motor that has not changed its design in almost 60 years.

Not to mention if you aren't using any boost then you are practicing a modified driving habit that will recognize mpg gains with or without the blower.

I have never known a facotry blown vehicle that had good milage. Nissan, chevs, rauch mustangs, all famous for how bad their milage is.

I know how injectors work. I actually build jeeps on a regular basis.

I've done all the internal and snake oil mods over the years. I'm not argueing speculation here.

I've done multiple air intakes, throttle bodies, piggy back tuners, an aluminum cylinder head, cam swaps, rollerized, electric fans.

I know what the results have been.

What have you done?

Take your 10 thousand dollars and go engineer yourself a blown 4 litre that gets you 22mpg.

Let us know how it turns out.

[Evil-Jeep]

I think to some it up it is best to say yes there are gains to be made, but the gains made vs money spent hardly make the effort worth it, as they will never be more than a 5% increase.
As I was saying before I only upgraded to more efficient components as the OEM stuff deteriorated, I would recommend changing to a washable filter such as a K&N (there is a bit of debate whether these allow to much dirt or not but since I see more pavement then mud these days I figured it was worth it) The fan swap was done more because I enjoyed the project and the cost was comparable to an OEM mechanical, as for gains maybe a bit but not enough to make spending the money worth it. The plugs needed to be changed, but I didn't need to spen on the E3s, new OEM's would have probably given the same increase for less money.

The most gain I ever noticed was after a recent tranny and transfercase flush and fluid change, this was worth every penny at about $120.

Wind will be more of a determining factor to mpg than anything else you will ever add to your jeep, Last year I emptied an entire tank from Calgary to West Edmonton Mall (fuel light came on as entered the parking lot) on the return trip I pulled into the driveway with more than half a tank left. the difference was a 75km/hr wind blowing from the north.

Bnine is right you could spend 10k on a 4.0L and get maybe 22mpg if your lucky, or you could swap motors out of a different vehicle and have the same result for half the price, or you can except the fact that you are driving a brick powered by a motor that uses the same technology as a 50 year old farm tractor.

[parabs]

You can't change the elevation where you live, so bothering to mention it is pointless.

We all know what air density does to power but it is still irrelevant for a couple reasons. Aside from the one I just described, people in lower elevations report the same milage we do. They just don't have the power issues that we do.

You can not compare a TRD engine to a motor that has not changed its design in almost 60 years.

Not to mention if you aren't using any boost then you are practicing a modified driving habit that will recognize mpg gains with or without the blower.

I have never known a facotry blown vehicle that had good milage. Nissan, chevs, rauch mustangs, all famous for how bad their milage is.

I know how injectors work. I actually build jeeps on a regular basis.

I've done all the internal and snake oil mods over the years. I'm not argueing speculation here.

I've done multiple air intakes, throttle bodies, piggy back tuners, an aluminum cylinder head, cam swaps, rollerized, electric fans.

I know what the results have been.

What have you done?

Take your 10 thousand dollars and go engineer yourself a blown 4 litre that gets you 22mpg.

Let us know how it turns out.

I dont know why you are turning this into a pissing contest.  I know you are well versed in jeep building.  I have read a lot of your posts, lots of good info.  I am not saying youre wrong either.  Most ppl build engines with forced induction to make bigger power.  That is fine.

I have seen the proof in buddies 4.0l v6 toyota tacoma.  What can I saw, I saw the proof.  At first, I didnt believe him, until he showed me monthly fuel receipts and the kms travelled that went with them (all as part of our reporting).  He was saving money on fuel at a rate that is much faster than you would think.  No it isnt the same technology, but the basic principal is the same, forced induction reduces the effect of elevation by pressurizing the manifold to create a more dense air charge.  This gives your engine the opportunity to work less to complete the same task.  As I said above, I was skeptical of all this, but the proof was in his numbers.

Right now my buddy has a vorteched 97 cobra, and when he is crusing down the high way he makes 0-1psi.  The engine will only create boost under load conditions...thats why if you rev the snot out of a blown engine in neutral it will make little to no boost.  No boost, no extra air, no extra fuel.

Factory blown shelby gt500's with a eaton blower (not very efficient) over a 5.4 dohc with that makes 550hp is rated for 32 mpg.  I would not call that famously bad mileage, but that is my opinion.

Internals on an engine really only involve the crank, rods, bearings and pistons...with changing these parts alone, I dont know how anyone could expect a change in mileage, save for going to a stroker then I would say you could anticipate worse mileage.  Head/Cam/Intake could have an effect, as the root of all your power and efficiently (as in where you make your power) comes from the head and the cam.  Electric fan will save you 3-4 hp.  K&N will get you 2-3 hp on a good day.

As far as "what I have done?"  I built up a N/A 5.0l mustang a few years ago, while my roommate was building up his vorteched cobra while another buddy was building (and blowing up) a 3.8l v6 mustang turbo that made 442 rwhp on a dyno in Calgary.  I have also ran a couple chevy Gen II LT1's into the ground, and thats about it.

I wont take " my 10 thousand" anywhere because I dont have a 10k go and frack around with my jeep fund.  I use my jeep for work.  I cant have it being unreliable. 

Oh, and for anyone who is interested, I ran to Sparwood BC today to supervise some drill cuttings disposal, which meant I was on site for a bit, on a logging road that has a speed limit of 30, fumed around at the CCS landfill in Pincher creek and drove home only to put on 611 kms and burn 84.6L of fuel.  That works out to 13.8l/100kms.  I dont have cruise so it was all drive by pedal, and when on the highway I tried to maintain a speed of 115kph, but I fell short of that due to the hills.

This Jeep has a factory rating of 15.0l/100km in the city (19mpg) and 25mpg on the highway as per the window sticker.

[FiEND]

my jeep is getting 14.1L/100Km driving back and forth on deerfoot during rush hours.  this with 120 pounds per wheel.  usually 350 km per tank which is almost 50L

my conclusion is:  our altitude make the air thin so my jeep has less drag which improves my fuel economy.

[TL-Iguana]

I have to agree with  Fiend, thank gosh the air here is thinner to help my tank to cut through it easier

In my XJ on 32's with a roofrack, air damming jerry cans on the rack, and a giant spare tire hanging off my bumper, and countless other heavy items in the back, I get about 14l/100km. Out of a 72 liter tank Im laughing if it goes for 450k....

[Rich99]

ok, that does it... i am buying electric.

see you on the trail.

http://jalopnik.com/5053639/jeep-ev-rock-crawling-the-electric-way

uhmmm, does anyone know if they have plugins at mclean?

[BlackYJ]

my jeep is getting 14.1L/100Km driving back and forth on deerfoot during rush hours.  this with 120 pounds per wheel.  usually 350 km per tank which is almost 50L

my conclusion is:  our altitude make the air thin so my jeep has less drag which improves my fuel economy.

That is pretty good Al.  I usually get about 16.5-17L/100km in my YJ.