inv3ctiv3
NAXJA Forum User
- Location
- Santa Barbara, CA
I also want to replace the sparks plugs and all that stuff, what do you guys recommend for spark plugs?
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Got OEM Grabber AT2's and MPG dropped 4mpg!?
- Thread starter inv3ctiv3
- Start date
- Location
- WA state
NGK platinum plugs for the newer heeps.
souske
NAXJA Forum User
- Location
- The land of competition
I liked my Ngk plugs, running autolite plugs now, they are meh. The bodies are rusting long before the tip is slightly eroded.
napa high end stuff for wires,.cap, and rotor
napa high end stuff for wires,.cap, and rotor
I was just going to post about this. I had a crappy set of some no name tires on my jeep but was getting 20-22MPG consistently. Then, I put on some Firestone Destination AT's and saw my mileage drop down to about 17MPG. I look around and see maybe I shouldn't be so concerned with that because I still seem to be doing a whole lot better than most.
I have replaced just about everything fuel, spark, exhaust and sensor related on here except the crank position sensor and cam position sensor.
The next thing I am going to do is replace the injectors with the 4 hole ones everyone talks about. I am getting some dogging in third and hesitation and jerk when taking off from low RPM.
I have replaced just about everything fuel, spark, exhaust and sensor related on here except the crank position sensor and cam position sensor.
The next thing I am going to do is replace the injectors with the 4 hole ones everyone talks about. I am getting some dogging in third and hesitation and jerk when taking off from low RPM.
br1anstorm
NAXJA Forum User
- Location
- United Kingdom
Just happened to be browsing and have looked through this thread.
Seems to me the MPG drop could be simply the result of the different tyres. Don't go chasing problems with sensors, throttle body etc if you don't need to. If the only change you have made that affected the MPG is the tyres, then most likely the tyres are the reason.
It's not just the issue of tyre circumference. New tyres will be a few millimetres "bigger" in diameter than worn-out bald ones, but that of itself won't cause huge MPG drop.
Nor is it only a matter of weight. New tyres with chunky tread may well be heavier than old bald ones. This may be a factor, but it's not that simple.
The key thing is something called "rolling resistance". This depends partly on the weight of the tyre. But it is influenced very much more by (a) the chunkiness of the tread pattern; and (b) the nature of the rubber compound and the tyre's structure - number of plies, sidewall flexibility etc. Also (c) tyre pressure is critical - an underinflated tyre will push your fuel consumption up.
Thus an aggressive deep-treaded off-road tyre (like the Grabber) will have much higher rolling resistance than a 'highway' tyre with a much smoother tread pattern and lots of thin grooves. An offroad tyre will also usually have a harder rubber compound, which will increase rolling resistance. The MPG difference between chunky tyres and smooth (highway tread or near-bald) will show up most obviously in comparisons of highway-driving (since off road, all sorts of other things will push your fuel consumption up!).
Over here in the UK and Europe, tyres now have to be labelled for their noise levels, their wet-weather grip, and their "fuel efficiency" (which is rolling resistance by another name). A is best, G is worst. For example, the General Grabber AT in the size I use is rated "F", and the BF Goodrich All Terrain (which is very chunky) is rated "G", while the Toyo Tranpath, a highway tyre, is rated "C".
So.... don't sweat too much over other tune-up issues - it's wise to check, but don't assume that is the cause of your MPG drop. I reckon it is down to your tyres.
Seems to me the MPG drop could be simply the result of the different tyres. Don't go chasing problems with sensors, throttle body etc if you don't need to. If the only change you have made that affected the MPG is the tyres, then most likely the tyres are the reason.
It's not just the issue of tyre circumference. New tyres will be a few millimetres "bigger" in diameter than worn-out bald ones, but that of itself won't cause huge MPG drop.
Nor is it only a matter of weight. New tyres with chunky tread may well be heavier than old bald ones. This may be a factor, but it's not that simple.
The key thing is something called "rolling resistance". This depends partly on the weight of the tyre. But it is influenced very much more by (a) the chunkiness of the tread pattern; and (b) the nature of the rubber compound and the tyre's structure - number of plies, sidewall flexibility etc. Also (c) tyre pressure is critical - an underinflated tyre will push your fuel consumption up.
Thus an aggressive deep-treaded off-road tyre (like the Grabber) will have much higher rolling resistance than a 'highway' tyre with a much smoother tread pattern and lots of thin grooves. An offroad tyre will also usually have a harder rubber compound, which will increase rolling resistance. The MPG difference between chunky tyres and smooth (highway tread or near-bald) will show up most obviously in comparisons of highway-driving (since off road, all sorts of other things will push your fuel consumption up!).
Over here in the UK and Europe, tyres now have to be labelled for their noise levels, their wet-weather grip, and their "fuel efficiency" (which is rolling resistance by another name). A is best, G is worst. For example, the General Grabber AT in the size I use is rated "F", and the BF Goodrich All Terrain (which is very chunky) is rated "G", while the Toyo Tranpath, a highway tyre, is rated "C".
So.... don't sweat too much over other tune-up issues - it's wise to check, but don't assume that is the cause of your MPG drop. I reckon it is down to your tyres.
crimsondragon
NAXJA Forum User
- Location
- NJ
The Grabbers are heavy mofos. With 7 ply tread and 3 ply sidewall, they're kind of overbuilt.