Gas Consumption Record - 6mpg

[RichP]

I thought about carb boarding the rad but we'll see. I have 112500 miles on the clock... I'll bet dollars to donuts the O2 sensors are original unless they put new ones in when my exhaust was replaced in 2002. I have no proof to tell though. As well my heater seems to be working just fine but when it's in use it makes my temps drop even lower and the needle will sit just a hair above the first 1/4 mark

I know the O2 can cause problems, BUT, a big but here, my 98 has over 300,000K on it, second engine, original O2's, cat and muffler and pretty much the same mileage. The more and more you talk the more it sounds like it's staying in cold loop.

 

[Leo Brazil]

I thought you all down there in brazil were running much higher ethanol levels then 10 or 15 percent, thought you were all mostly 85% and above... with some running on pure alky..

Only my self during the weekend watching the games on TV runs on pure alky...just kidding....(not really)...

In fact, our gasoline have 25% of ethanol (from sugar cane). But there are a lot of Engines running with only Ethanol with 14% of water....Those engines are great, they have 15:1 compression rate and 20-25% extra HP compared to the same engine model that runs with gasoline.
Diesel is allowed only for trucks and some SUVs and Pick ups.
Now there are some engines that can accept both gasoline, ethanol or whatever mixture you decide....there is a special sensor (similar do O2) that detects the mixture and tube the ECU for correct fuel injection.
And now with all this Global Warning talking many vehicles here are using Natural Gas, specially mid and big engines....Natural Gas is pretty cheap down here....but you have to install an extra tank and that kills your trunk room....but that's not for me, at least for awhile....that's the reason I'm still have some hope about improve my MPG....

 

[RichP]

Only my self during the weekend watching the games on TV runs on pure alky...just kidding....(not really)...

In fact, our gasoline have 25% of ethanol (from sugar cane). But there are a lot of Engines running with only Ethanol with 14% of water....Those engines are great, they have 15:1 compression rate and 20-25% extra HP compared to the same engine model that runs with gasoline.
Diesel is allowed only for trucks and some SUVs and Pick ups.
Now there are some engines that can accept both gasoline, ethanol or whatever mixture you decide....there is a special sensor (similar do O2) that detects the mixture and tube the ECU for correct fuel injection.
And now with all this Global Warning talking many vehicles here are using Natural Gas, specially mid and big engines....Natural Gas is pretty cheap down here....but you have to install an extra tank and that kills your trunk room....but that's not for me, at least for awhile....that's the reason I'm still have some hope about improve my MPG....

The big hoorah up here is ethanaol, bad move on our part, we don't have the grains or plants to support it, not without driving up food prices. The hybrid vehicles are a total waste of money and are only feel good things when their total environmental impact is even worse than what we have. Nobody is talking hydrogen, mainly because it's something that the average homeowner can crack from either water or air and the oil companies are not about to let that genie out of the bottle, honda had a complete turnkey system, car and generator you hang on the garage wall. They made a big thing out of it for about a couple of weeks and then got real silent on the subject and pulled the info from their web site. Iceland is either 50 or 75% hydrogen and they have put it on the front burner to be totally hydrogen in another 5 years.

 

[Leo Brazil]

The big hoorah up here is ethanaol, bad move on our part, we don't have the grains or plants to support it, not without driving up food prices. The hybrid vehicles are a total waste of money and are only feel good things when their total environmental impact is even worse than what we have. Nobody is talking hydrogen, mainly because it's something that the average homeowner can crack from either water or air and the oil companies are not about to let that genie out of the bottle, honda had a complete turnkey system, car and generator you hang on the garage wall. They made a big thing out of it for about a couple of weeks and then got real silent on the subject and pulled the info from their web site. Iceland is either 50 or 75% hydrogen and they have put it on the front burner to be totally hydrogen in another 5 years.

To tell the truth with my experience with Ethanol is Engines that were originally design for Ethanol are really great. More powerfuel and efficiente than gasoline ones....but the problem is this BS mix they make here and trust me, they'll do the same in US very soon....Hybrid engines we have here is another BS. As gas engines normally have around 9:1 compression rate and Ethanol 15:1 the hybrids here have 9.5:1....to make a long hystory short, those "Flex" engines (like they call here) never give you a good MPG of eficiency in gas nor ethanol.
I agree with you about Hydrogen....some Universities already have some prototypes using it but like you said they appear once in awhile and just vanish just like if they never exist. You know, the oil industry is the base of most of economies around the word if they give too much credit for things like that what would happen ?
Just a curiosity....the "big boom" here now is about Bio-Diesel a mix between regular Diesel and a vegetal oil.....When I was a kid there was an old japanese guy with a pretty old Chevy pickup truck C20 with a diesel engine. This guy used to ask all the neighborhood for their cooking oil wastes, you know like used french fries oil....this guy mix this oil waste with a little bit of ethanol just to keep the viscosity as same as regular diesel and he used it in his truck.....This was earlier 80's and I've never seen this guy with a Engine problem.....Today, the "big boom" is the Bio-diesel and this guy was already using it about 30 years ago....

 

[tkjeeper]

hey jroc, fellow Ontarian here, I have a 93, had a big problem with fuel economy this winter, last summer when I switched to synthetic oil my km's per tank went from 630 kms to 703 kms! I was amazed, that was with straight stock tires, 225's. Went to 31" dueller at's this winter and installed a remote starter, went down to 450 kms a tank! But I let her warm up for 15 mins morn and night before leaving home and work. Now back to normal weather and no warming up, I'm back to 550 kms, approx. I can live with that. No help for your problem but the others had some great ideas, start with a tune up I think would be the wise thing. Good luck.

 

[J-Roc]

man if you are cranking out 700KM's per tank that is FN' nutty. I can't even DREAM about getting those numbers. Pretty much 25mpg, do you do a lot of highway driving TK?

I myself run Amsoil, with 180,000km's on the clock, those are impressive numbers to say the least. Also do not forget to factor in your speedo since it will be off with the larger tires, you are probably close to 600km/tank. My speed is 2.1% off, yours is 10.4% off

607km/tank if my math is correct, I don't know wtf you did but please share your specs hahaha I would KILL for that mileage

Btw, are you a member on Jeepkings?

 

[Mtb Jak]

What do you guys recomend for a Full engine tune up for a 2000?? I changed the oil put in a good oil filter and new air filter. It has 122,XXX on the clock and i average 280 miles on a full tank! Im moving to a 3 inch lift and 31s befor summer and just want to not take the hit to hard!


Thanks!

 

[Blaine B.]

Plugs, fuel filter, o2 sensors?

 

[bjoehandley]

First off, J-Roc, have you tried 87 octane instead of midgrade?
Secondly, for both J-Roc and Leo, have you regeard for the larger tires or taken that into account when figuring mileage? On my '98 it can make upto nearly 2mpg difference!
Third , have you tried driving the trucks like normal, I didn't see any improvement by babying mine, the only plus was listening to stock 4 cylinder Honda Accord's screaming to keep up when I'd accelerate and never top 3K.

 

[Leo Brazil]

First off, J-Roc, have you tried 87 octane instead of midgrade?
Secondly, for both J-Roc and Leo, have you regeard for the larger tires or taken that into account when figuring mileage? On my '98 it can make upto nearly 2mpg difference!
Third , have you tried driving the trucks like normal, I didn't see any improvement by babying mine, the only plus was listening to stock 4 cylinder Honda Accord's screaming to keep up when I'd accelerate and never top 3K.

Gas in Brazil with 25% of Ethanol has 92 octane due betther detonation rate of Ethanol but I'm aware that this mix reduces in 10 to 15% MPG but I'm loosing much more than this...
I have 235 tires and gear still stock.....I'm driving like a kid never going up to 2200 rpm....But I have a doubt about this: What would be better for MPG, increasing the rpm slowly (What I'm doing) and let the tranny changes at 2000 or sometimes 2200 rpm or increase as fat as I can, to shift the gears faster ?
Anyway, I'm gonna let my XJ tomorrow for a tune-up, check the injectors and O2 sensor....Exaust system...despite it sounds perfect but I'll check that and it's pretty easy to do by my self.
Canadians that using metric system like us here can be impressed if I say I can't get more than 400Km/tank that means 250 miles/tank....I'm sure even you guys using the poorer gas ever will get better MPG than me.

 

[RichP]

Gas in Brazil with 25% of Ethanol has 92 octane due betther detonation rate of Ethanol but I'm aware that this mix reduces in 10 to 15% MPG but I'm loosing much more than this...
I have 235 tires and gear still stock.....I'm driving like a kid never going up to 2200 rpm....But I have a doubt about this: What would be better for MPG, increasing the rpm slowly (What I'm doing) and let the tranny changes at 2000 or sometimes 2200 rpm or increase as fat as I can, to shift the gears faster ?
Anyway, I'm gonna let my XJ tomorrow for a tune-up, check the injectors and O2 sensor....Exaust system...despite it sounds perfect but I'll check that and it's pretty easy to do by my self.
Canadians that using metric system like us here can be impressed if I say I can't get more than 400Km/tank that means 250 miles/tank....I'm sure even you guys using the poorer gas ever will get better MPG than me.

Right now I'm running stock 3:08's in my 98 with LT235R15 BFG/AT KO's, did tire pressure on saturday while doing all the spring oil changes and lubes on all the jeeps and wifes oldsmobile. My tires are at 38psi.
When I do use it to commute I very rarely take it over 3000rpm and only use 5th gear when I go above 70mph, if I use 5th for cruising at 65 my gas mileage goes right in the dumper. The same is also true on one of my TJ's, 2.5L, 5speed, 4:10's and 31's, 20-21mpg around town but it never goes into 5th and I keep the revs between 2500 and 3000rpm. On the hiway wind makes a large impact on mileage with that flat nose and windshield. The worst I have gotten with that one is 18mpg, the TJ with the 4.0/5speed is lucky if it gets 18mpg.
If they really do go ethanol here in the US I can only hope they bring back the high compression engines but my guess is they will all be flex engines and low compression. I wonder if a supercharger could be used to boost compression and improve mileage.

 

[MudDawg]

Joe brought up a point regarding octane number.....You should always run the lowest octance fuel the motor will operate on without pinging.....the reason is counterintuitive but basic.....the higher octane the fuel, the lower the specific heat content per pound...engines are heat powered...the lower the btu per pound, the lower the combustion temperature/the lower the cylinder pressure/the lower the power output/the lower the output, the more throttle it takes to achieve the same speed under load....it's a vicious circle..the fact that the engine runs too cool is another indicator that the engine is not loading.....its all about thermal efficiency. The hotter the engine can reliably be run, the more efficient it will be.

 

[J-Roc]

when I run 87 octane I see a drop of 50-70km's per tank... thats why I started running 89

I have a full tank of 89 right now, next time I go to fill up I'll use 87 and note the differences

 

[Leo Brazil]

If they really do go ethanol here in the US I can only hope they bring back the high compression engines but my guess is they will all be flex engines and low compression. I wonder if a supercharger could be used to boost compression and improve mileage.

Flex engines like they call them here really sucks....they cost 20% higher than regular engine models and this system is not efficient enough....it's a good thing for lazy people that's all...

A common practice here is convert the Engine to run with Ethanol a good job consists in replace the whole fuel line, pump, filter, injectors to the ones more corrosion resistent. The tough job is take the head of the engine to reduce its height and this way increase the compression for 15:1. Re-map the ECU and chage the distrubuition point (if aplied) to Ethanol.....doing all those steps your Engine will be a Monster. It gets at least 15% more HP and after 10,000 miles your engine oil and plugs will looks as clean as brand new. The mileage is not good as with gas (15% less) but ethanol is half of gas price here....
Some models here like Ford Fiesta (European Design) with 4 cil 1.0L have stock compression system. It works good is you consider a kid's toy with 1.0L....

 

[Ecomike]

Joe brought up a point regarding octane number.....You should always run the lowest octance fuel the motor will operate on without pinging.....the reason is counterintuitive but basic.....the higher octane the fuel, the lower the specific heat content per pound...engines are heat powered...the lower the btu per pound, the lower the combustion temperature/the lower the cylinder pressure/the lower the power output/the lower the output, the more throttle it takes to achieve the same speed under load....it's a vicious circle..the fact that the engine runs too cool is another indicator that the engine is not loading.....its all about thermal efficiency. The hotter the engine can reliably be run, the more efficient it will be.

My experience has been that I get consistently get better gas mileage with higher octane gas. Usually about 10% better mileage with 93 versus 87.

 

[Blaine B.]

I thought higher octane fuels burn quicker and would actually give you a slight decrease in MPG?

 

[Ecomike]

To tell the truth with my experience with Ethanol is Engines that were originally design for Ethanol are really great. More powerfuel and efficiente than gasoline ones....but the problem is this BS mix they make here and trust me, they'll do the same in US very soon....Hybrid engines we have here is another BS. As gas engines normally have around 9:1 compression rate and Ethanol 15:1 the hybrids here have 9.5:1....to make a long hystory short, those "Flex" engines (like they call here) never give you a good MPG of eficiency in gas nor ethanol.
I agree with you about Hydrogen....some Universities already have some prototypes using it but like you said they appear once in awhile and just vanish just like if they never exist. You know, the oil industry is the base of most of economies around the word if they give too much credit for things like that what would happen ?
Just a curiosity....the "big boom" here now is about Bio-Diesel a mix between regular Diesel and a vegetal oil.....When I was a kid there was an old japanese guy with a pretty old Chevy pickup truck C20 with a diesel engine. This guy used to ask all the neighborhood for their cooking oil wastes, you know like used french fries oil....this guy mix this oil waste with a little bit of ethanol just to keep the viscosity as same as regular diesel and he used it in his truck.....This was earlier 80's and I've never seen this guy with a Engine problem.....Today, the "big boom" is the Bio-diesel and this guy was already using it about 30 years ago....

Mixed vegetable and ethanol would not work well, I do not think they even stay mixed!

He was probably making real bio-diesel which mixes sodium hydroxide (caustic) with the ethanol to make sodium methoxide first (he may not have mentioned that). The sodium methoxide is then reacted with the vegetable oil to produce bio-diesel and some glycerin. The two are gravity seperated and the glycerine is used to make soap and the bio-diesel (a man made ester) is used as bio-diesel fuel. The used vegetable oil needs to be filtered first and the bio diesel needs to washed with water before it can be used as fuel. The water wash removes any excess caustic and soap byproducts from the esterification reaction.

On the hydrogen topic, I did some research on the topic last year, and the real problem or drawback, which no one has an answer for yet, is the storage problem. 200 miles of hydrogen storage for an eighteen wheeler requires huge storage tanks (and / or refrigeration compression equipment to liquify it which has an enegy comsumption penalty and needs added insulation) that takes up 2/3 of the cargo space of an eighten wheeler to just store and haul 200 miles worth of hydrogen fuel. Then it also requires energy to make the hydrogen.

One of the most promising new technolgies being installed now is the biosolids waste to synthetic crude oil reactors. They use high pressure high temperature steam with out oxygen to thermally convert biomass waste into a synthetic crude oil. Oil prices are high enough now to make it cost effective and it ellimates landfiling and burning these wastes for disposal.

 

[Ecomike]

The big hoorah up here is ethanaol, bad move on our part, we don't have the grains or plants to support it, not without driving up food prices. The hybrid vehicles are a total waste of money and are only feel good things when their total environmental impact is even worse than what we have. Nobody is talking hydrogen, mainly because it's something that the average homeowner can crack from either water or air and the oil companies are not about to let that genie out of the bottle, honda had a complete turnkey system, car and generator you hang on the garage wall. They made a big thing out of it for about a couple of weeks and then got real silent on the subject and pulled the info from their web site. Iceland is either 50 or 75% hydrogen and they have put it on the front burner to be totally hydrogen in another 5 years.

Natural gas and liquified propane make a lot more sense than hydrogen due to the storage problems with hydrogen.

Most of the current ethanol usage as a gasoline additive in the USA has been to replace the recently outlawed oxygenation additive MTBE, which was added to lower gasoline volatility and improve combustion from an environmental perspective, meaning to reduce VOC emissions from vehicles in the USA. MTBE was showing up in ground water sources from leaking US tanks so they replaced it with the less toxic and more biodegradable ethanol.

It has only recently been heavily promoted as a partial answer to help replace crude oil.

 

[Ecomike]

I thought higher octane fuels burn quicker and would actually give you a slight decrease in MPG?

The higher the octane, the slower it burns. The lower the octane the faster it burns, which in some cases causes pre-ignition knock.

 

[torfinn]

Octane rating has nothing to do with burn speed. It notes the fuels ability to self detonate with compression and temperature. Higher octane means less self detonation. High compression engines must have high octane.


Torfinn