Fuel economy ideas and MPG Boosting (merged threads)

[Janet's Husband]

The use of "Fast Flow" air filters i.e. K&N have there drawbacks.
They also flow more dirt with all that air. Now I haven't figured out the difference in the cost of fuel vs. early wear on an engine.
Take a look at this site. http://home.usadatanet.net/~jbplock/ISO5011/SPICER.htm
Some interesting information, I've decided the AC filter is what I'm going with for now, still only 36000 on the Duramax.

[Pick]

I read that test, it's great information. However, I changed my intake out to an AFE, with the NEW Proguard 7 filter element. In their advertisement, they have a guy wearing a white glove, sweeping the inside of the intake tube, showing it clean, with the new element, vs dirty with the old style. Makes the turbo a lot louder too.

[JeepinAudiophile]

A simple intake system upgrade will improve mpg. For the GM applications I am a fan of the Outlaw Intake system which is what I am going to use on my truck, but there are a lot of them out there... just remember to do your research as anyone can make an intake system, but to do it right it takes proper engineering...

[RoadKingMoe]

I can't find the link anymore, but at one time a university did a wind tunnel study of pickup trucks. They found tailgate nets or removing the tailgate didn't lower drag. They found camper shells INCREASED drag and that the only thing that lowered it was a tonneau cover.

Clean K&N filters improve air flow, but as said don't filter as well. One study of them on generators found increased silica in the oil. The dirtier they get the better they filter, but the less they flow. I certainly use them in performance applications, but those are motors I expect to have to rebuild more often anyway.

[fastrob]

AM on vacation this week, took a nice nap in the Airstream yesterday.
I must say that when the going gets tough, take a nap, you feel better.

We bought a Corolla for the family. The three teen agers have more leg room in the Toyota rather than the Sierra and it gets 35-40 mpg$!
They would rather ride in the Corolla than the Sierra. Do you wonder why GM is in trouble?

I wonder if the Toyota would pull the Airstream if I pulled out the interior?

[jordandvm]

With the gas prices through the roof, and not expected to go down anytime soon, I thought a thread discussing ideas forums folks have tried and worked (other than the basics of correct tire pressure, correct highway speed, and avoiding quick stops and starts) with their tow vehicles that we may all benefit from.
I took in my Chevy Avalanche for an oil change and check of the transmission fluid and brakes before I embark on another trip this weekend. I asked the service manager if there were any after market add-ons that might improve fuel economy on my truck.....and he said he had his exhaust system replaced on his own Yukon with a "cat back" system, which is supposed to decrease workload on the engine (don't know how this works) and improve power as well. He said he's getting 2 mpg more on the highway with this modification. Now I figure I'll be driving the Avalanche another 80K miles in the next 5 years (20K on it already). Let's say I average 11 mpg city/highway.......that's 7273 gallons of gas to propel me.......and let's say I pay an average of $3.00/gallon (probably more) for gas over 5 years.......that's $21,819 for gas cost. If I purchase the cat back exhaust and average 13 mpg, I'd only be burning 6154 gallons of gas at $3.00/gallon and would save $3357 in gas costs over 5 years. I'd say that's a pretty good savings for the modification that initially would cost me $375 installed (quote today from muffler shop). Also I've heard the cat back exhaust system will boost power, so may help to get up some of those steep grades. Does this sound like a good idea??
Any other ideas folks have tried and worked successfully are appreciated..........gas ain't gettin any cheaper!!!!

[Janet's Husband]

Jim

Those of us with diesel trucks have pretty much the same tricks available for mileage improvement.
1.) Exhaust replacement, less back pressure.
2.) Hi flow airfilter system.
3.) Tuning chip for more power or fuel mileage.
4.) Changeing the waste gate.
5.) Keeping the tire pressure up.
6.) Keep your speed under 60mph
7.) Don't race, slow even acceleration.
8.) keep the weight down i.e keep your fresh water tank empty until the last moment, buy groceries at your destination, empty your grey and black tanks.

That's my thoughts for the moment, I am all ears for anything else, with diesel running at $3.15 per gallon any help is welcome.

[StingrayL82]

I guess I can still count my blessings that where I live (Harford Co., MD) diesel is still $2.89/gal.

Frederic

[jordandvm]

Could you elaborate further as to initial cost of these (ie the mods) vs fuel economy? And have you done any of these on your truck?
Thanks

[Janet's Husband]

Originally Posted by jordandvm

Could you elaborate further as to initial cost of these (ie the mods) vs fuel economy? And have you done any of these on your truck?
Thanks

1.) Exhaust replacement, less back pressure. $450 to $650 The claim is about 5 to 13% fuel mileage improvement.
2.) Hi flow airfilter system. $200 to 300 the claim is 7 to 10% fuel mileage improvement.
3.) Tuning chip for more power or fuel mileage. $300 to $850 The claim is 1 to 3 miles per gallon.
4.) Changeing the waste gate. $200 to $300 The claim is 1 or 2 miles per gallon.
5.) Keeping the tire pressure up.
6.) Keep your speed under 60mph
7.) Don't race, slow even acceleration.
8.) keep the weight down i.e keep your fresh water tank empty until the last moment, buy groceries at your destination, empty your grey and black tanks.

It looks like you can spend about $1150 to $2100 and claims you can get about 3.2 to 7 miles per gallon again I say claims. if you are as skecptical as me it looks like 1 to 3 miles per gallon saved with these upgrades.

Useing 75000 miles as a base model. 3947 gallons @ 19mpg my non-towing mileage, 3750 gallons @ 20mpg, 3409 @ 22mpg
If I was to get 1 additional mpg I would save 197gals @ $3.00 = $591.00.
If I get an addtional 3mpg I would save 538 gallons @ $3.00 = $1614.00
At first glance you would have to do this really smart and get real good deals on your parts. Of course if the price of fuel goes up say to an average of $3.50 per gallon it would be $689.50 or $1883.00.

Towing I get about 14.7 mpg but the savings differentials should apply at this mpg also. I guess you should use a differential of + or - 10% of the stated values.
I'm going to have to investigate thie add on equipment situation further.

[3Ms75Argosy]

Jim, I did do a cat back (Gibson) with my Astro when I put my 350 V8 into it. It sounded so cool (like a muscle car), and the van went like stink. Fuel economy disappeared, as I just couldn't get over the sound of the engine at full song (neither could the church going mom I lent the van too when their family car gave up the ghost ). The idea is that less pressure from the muffler will let the exhaust gasses exit free'er (sp?), allowing the engine to work less to expell the exhaust gas, and improving fuel economy. You MAY see a bit of improvement in fuel economy and power, but, think about hearing that sound as you tow. You'll be using the engine under load, and there will be more noise. Banks, and Borla make good systems, but again, see if you can listen to one installed.

How's this to make you feel better - our van without a load gets 13mpg on the highway (even if it fell off a cliff, it would get 13 mpg). That's after new plugs, wires, distributer cap and rotor, airfilter, O2sensor and PVC valve. I.E., at it's best. On our CA trip, worst I saw was 5, yes FIVE!! mpg in the CA heat (radiator fan tripped on all the time at 112 degrees ambient temp), AC on, and strong headwinds. Best is 8.8 mpg.

In Ellensburg, Dodge sponsored the Rodeo, lots of promo for the Dodge 3500 Dually ("official truck" of PRCA - cool decals!!). I got Mona "that close" to looking at an extended cab one...till I figured that, even with employee pricing, $35,000 could buy me a lot of gas at $3.00/gallon....van's paid for. I could also use that mystical $35,000 towards a new CCD.

I don't look when I fill it up anymore, just put the card in and press "no" to the receipt.

As an aside, diesels get better mileage with the above add on's, but I honestly don't know why. I have seen some impressive claims by Banks with their "Git" systems and the diesels.... I certainally would think about it if I had one. Gas systems really don't seem to get as much improvement...I'd say 1 - 3% ideally (cat back with new aircleaner system). Gary, I'm so jealous of your gas mileage!
Marc

[uwe]

I noticed a slight improvement in mileage after changing my lubricants to synth from Amsoil. ( everything but the transmission at this time)
Picked up about 8/10th of a mile hwy.
Currently 14.5 combined, 17.9 highway, and 10 to 12.5 mpg towing.
this is a 1997 Suburban 1500 2wd, with a 5.7l Vortech and 3:73 axle ratio.
I did not notice any improvement after installing a $ 50.00 K&N Air Filter, btw.
My biggest improvements in fuel mileage are always related to driving style. I have seen close to 20 mpg hwy, going 60ish mph, with the cruise control on, and I can nurse the Suburban to 15 combined if I keep it under 2500rpm, and just barely nudge it of the line in city driving. It still keeps with the flow of normal traffic this way, bu there's no sensation of acceleration, or cool V8 sound.....
It also helps to look ahead and coast to a stop if you see a red light way ahead. Braking is essentially wasting built up energy that you have already paid for, while coasting, and possibly avoiding the stop altogether can save a lot of fuel.
My drivetrain is completely stock, btw. with the exception of the air filter.

[Pick]

I am going to install a propane injection system on my Duramax diesel. Higher diesel mileage, cleaner lube oil, plus 100HP gains are the advantages. With a the 35 gallon propane tank, I can increase my cruising range quite a bit. Propane is only more economical if you can purchase the gas for about 2/3 the cost of diesel. This is possible to do if you purchase propane at a Flying J truckstop.

[fastrob]

A buddy has an Isuzu diesel in his delivery truck. I has 4 cylinders and gets great mileage, he says. The thing is as aerodynamic as a shoe box but delivers the goods.

Eventually these things will be available in a pickup style truck so I can hang a plow for snow, deliveries and haul my Airstream.

American manufacturers seem to be dead or dying, until the market responds with a suitable 4 cyl diesel 4 wheel drive we use the GM Sierra and gas.