why am i get such terrible gas mileage?

[tjkj2002]

My v8 Mustang got 26 highway

Newer Vettes get over 30mpg's on the highway due to more power then they need to cruise at 65-75mph so they can drop the engine rpm's very low.Heck a Viper lugs at 1200rpm's at 65mph in 6th gear but the V10 makes so much torque it can maintain that speed at that rpm and still return 22mpg's.


Funny thing is like with a Vette able to get over 30mpg's on the highway you still have to pay the gas guzzler tax:shrug:.Last time I was back home I poked around the Ford dealership,they had a new Mustang GT and right beside it was a Roush Mustang.The regular GT was rated at 15 city and 22 highway,the Roush was rated at 16 city and 25 highway but because the Roush name was on the Mustang you had to pay $3300 extra for the gas guzzler tax but got better mpg's then the regular GT.

 

[Sanphred18]

A lot of websites will talk up the MPG advantage of a snorkel...have you seen any difference?

 

[iamweasel]

I'm interested in that too. I saw a post somewhere here where I guy said he monitored his intake temps before and after fitting a snorkel.
Unsurprisingly, intake temp was a few degrees colder with the snorkel.

 

[Okura_hubby]

The Snorkle is acting like a forced air cold intake. You can fabricate an internal forced cold air intake.

Why are we compairing gas economy of Vipers and Vette's to Jeep Liberty's? If my Jeep was as low and aero as either one of those I would be getting twice the millage I am now.. Why not lets compair it to a Toyota Prius or Honda Civic Hybrid shall we? If I had 500hp on my Liby I wouldnt be complaining so much in getting in the teen's for MPG.

I am actually floating the idea of hot rodding the Liby, I know the 5.7L would be just too much engine to fit under the hood, but the 4.7L would probably fit. I heard certain years used the same ECU and Trans. I heard the 3.7L is just a 4.7L that is missing 1 bank of pistons. I was thinking of finding a donar Dodge Dakota that had the 4.7L. I read somewhere if the year was right electronically it could be done. But this would get into big bucks for just a Liby so I dono. Just the Liby is underpowered and not very effecient.

 

[Ry' N Jen]

Just the Liby is underpowered and not very effecient.

I cannot complain about the fuel economy!
Mid 20's mpg I think is pretty good for a lifted KJ with bigger tires!
As far as being under powered...
I kept up just fine off road with an older Cherokee with a stroked straight six with 325 foot pounds of torque!
And that was before re-gearing!

 

[Slava]

I cannot complain about the fuel economy!
Mid 20's mpg I think is pretty good for a lifted KJ with bigger tires!
As far as being under powered...
I kept up just fine off road with an older Cherokee with a stroked straight six with 325 foot pounds of torque!
And that was before re-gearing!

I also could not complain about MPG, it is not bad at all. Speaking about under power, I had HEMI 5.7 on my RAM 1500 and yes, it rocks!!! But it also requires Octane 89 and drinks 50% more then KJ. KJ is not a sport vehicle and was not planned to be it :shrug: IMHO, the main difference between those engines is, Libby's 3.7 works mostly on low RPM while HEMI 5.7 starts to wake up at high RPMs. Again, this was my impression.

 

[Ry' N Jen]

Yeah, stuff a Buick Grand National V6 under the bonnet!

 

[Okura_hubby]

Why do something half way when you can do it all out

You must be registered for see images

What I am saying is underpower. Is you want to overtake someone you got to rev the crap out of it. I just think it really use a few more horses..

I got a friend here in NC who put one of those GN engines in a Nash Metropolitan. He just just put a LS1 in a Microvan.

I am curious what engine the guy that made those fender flares is putting in. Probably a 4.7L, which you can get a supercharger kit for that. You probably with right rework be 400HP

 

[tjkj2002]

I am curious what engine the guy that made those fender flares is putting in. Probably a 4.7L, which you can get a supercharger kit for that. You probably with right rework be 400HP

302 SBF,carbed.

 

[Ry' N Jen]

302 SBF,carbed.

Nah!

Stand alone fuel injection.

Way more efficient!

 

[tjkj2002]

Nah!

Stand alone fuel injection.

Way more efficient!

That is what KJWildman is putting in his KJ.When my V8 swap is done it will have a solid 500hp/500lbs-ft of torque with FI.

 

[Ry' N Jen]

That is what KJWildman is putting in his KJ.When my V8 swap is done it will have a solid 500hp/500lbs-ft of torque with FI.

My neighbour's got a Buick Grand National engine just sitting there...
6=8!

 

[iamweasel]

The Snorkle is acting like a forced air cold intake.

Yeah, I get that... I was just wondering about 'real world' results...

 

[Ry' N Jen]

At the end of the day, it is proven that a snorkel does not offer any real
"Ram Air" performance though!
It's main function is really for water crossing despite what allot of people say.

Once again, search this forum and you will find links to tests that prove what I just said.


Some claim that a snorkel ***** cleaner air because it draws it in from up above the roof line.

Again, there is enough proof that shows that the filters get dirtier faster!


Regardless, I like them. They look cool!

 

[Bulli]

I've scanned through this thread quikly and feel that if your car is in good nick and the engine well maintained you can't complain about mileage. I get 11.7mpg in daily rush hour traffic. When on the back roads and highway i get 18.81mpg. That compares with The toyota's and Land Rovers.
My wife with her 2010 Ford Focus 1.8 Si gets 19.6mpg in rush hour traffic. But she drives halve the car i do with a gas engine more than halve the jeep's engine. but she doesn't get halve the mileage. In other words the Jeeps mpg is better than a 2010 1.8 Focus! Fuel for thought.....

 

[Phil + Neela]

My wife with her 2010 Ford Focus 1.8 Si gets 19.6mpg in rush hour traffic.

That's it? That seems kind of low... my wife's 2002 Honda Civic has a 1.7L and it gets upward of 30 just hanging around town. If it weren't so small, we'd take it on more roadtrips becasue it gets over 35 on the highway.

Also confirming "If you wanted better mileage, you shouldn't have gotten a Jeep"

 

[Luke]

I don't usually keep track of my fuel economy but ... I just did a nice tidy 1050 km round trip taking my daughter to university. Half of the trip the KJ was filled to absolute capacity plus 3 occupants.

80/20 hwy/city driving... 21 mpg or 11L per 100kms

...not bad at all... If I could get my cruising speed down closer to the speed limit I'm sure that number would increase


edit : Just a quick thought are all of you using the odo correction factor for your increased tire sizes???

 

[Ry' N Jen]

Yup, I had the speedo recalibrated/ pinion reset.

 

[Bulli]

That's it? That seems kind of low... my wife's 2002 Honda Civic has a 1.7L and it gets upward of 30 just hanging around town. If it weren't so small, we'd take it on more roadtrips becasue it gets over 35 on the highway.

Also confirming "If you wanted better mileage, you shouldn't have gotten a Jeep"

It's 12L/100km and that equates to 19.6mpg. Thats it. Stop go all the way 7km takes up to 40 minutes. And the Focus only have 8000km on the clock.

Regarding the jeep, its intresting to note that with the 31'' BFG's the speedo shows 120km/h and the GPS shows 121km/h. Spot on i'll say. With the standard 235/16 the speedo was reading 120 and the GPS 114km/h.
Oh, i did not re-gear. Do not feel the need yet.

 

[J-Thompson]

Any 1 who has a car with an engine smaller than 2.0L
That is naturally aspirated and can not get 30 mpg
Is doing something wrong
My wife drive a VW Tiguan ,same size as a rav4 and CR-V
She does not drive slow and with the 2.0T she can pull
22+ city and 25+ average ,mixed driving

If you are not getting 17-18 average out of a basically stock
KJ you need to have it serviced