Getting Max Fuel Mileage

[web]

Thanks for the BSFC data, very interesting.

I must say though, that synthetic oil, wheel bearing grease type etc are not worth your while. I have tried such things in the past and never noticed even a .01 mpg difference. If everything spins smooth to the touch and no brakes are dragging severely (which you would smell if it ate any appreciable power), there is not much you can do besides adjustments to the engine itself and perhaps trying to reduce air drag a bit.

[farkman]

Web

Just because you never noticed a difference in your fuel economy doesn't mean that synthetics don't work. I tracked my mileage very accurately, driving the same route everyday, from home to school, and averaged 38-40 mpg. When I changed to Amsoil gear oil my next tank went up to 42 mpg. There is nothing else I can account for that would have increased my mileage this much. Driving conditions were nearly the same as well. Rammstein will tell you the same thing, he changed his gear oil to Redline and got a 2-3% increase in fuel economy. I do admit using synthetic grease for the wheel bearings won't do much, but every little bit helps and it's easy enough to do.

Peter

[RAMMSTEIN]

I went from the factory 75W90 to Redline MTL 70W80.

From 3 to 5% difference from last year.

[fspGTD]

Back when my Rabbit was a daily driver and I was measuring fuel economy on it  :lol:  I recall switching from 15W40 mineral oil to 5W40 synthetic made a 3% improvement in fuel economy.  Furthermore, it was noticeable...  especially in cold conditions the engine started easier, and when it ran it just felt "freer" driving on the freeway, etc and just plain had less friction I think and a bit more more torque to boot.  Lugging it up a hill I could keep it in gear instead of downshift in some scenarios.

[fspGTD]

I wouldn't be so quick to switch to synthetics. Synthetic oils carry a detergent factor to them that tends to clean out all the "crud" around seals which will cause them to leak. So, if you want to run synthetic be prepared to change all the associated seals (engine or trans).

Although early formulations of syntheitcs may have caused this, it is no longer true (and hasn't been for a long time)...  Taken from http://www.mobil1.com/why/myths.jsp :

Myth: Mobil 1 will leak out of the seals of older cars.
Fact: Mobil 1 does not cause leaks. In fact, new Mobil 1 with SuperSyn™ was tested in dozens of industry standard and OEM tests to prove its seal performance. It is fully compatible with the elastomeric materials from which all automotive seals and gaskets are made.

ExxonMobil engineers are wary of conventional oils that tout their use of additional seal-swelling agents. With extended use, these agents can over-soften engine seals, resulting in leaks. More to the point, an oil additive will not rejuvenate worn or damaged seals. The damaged seal may have been caused by a worn rotating metal component in the engine.

If an older engine is in good condition and does not have oil leaks, Mobil 1 with SuperSyn™ provides the same advantages as when used in a new engine. ExxonMobil recommends taking measures to repair the leaks, then using Mobil 1 with SuperSyn™. ExxonMobil also always recommends following the automobile manufacturer's manual for the proper oil to use.

[web]

Just because you never noticed a difference in your fuel economy doesn't mean that synthetics don't work. I tracked my mileage very accurately, driving the same route everyday, from home to school, and averaged 38-40 mpg. When I changed to Amsoil gear oil my next tank went up to 42 mpg.

Right. I have tried everything BUT gear oil and NOTHING made a difference. Now of course it COULD be that gear oil is the ONE area where a decent improvement can be made, but color me skeptical.

Nevertheless, if it was mainly gear oil you were talking about, I stand corrected for now. I still stick with my statement about engine oil and wheel bearing grease though. They just don't make a worthwhile difference whenever I tried anything like that. Of course there IS a very slight difference between old and fresh engine oil (probably more so on a diesel than a gasser), but that's about it.

Marcel

[vwmike]

I wouldn't be so quick to switch to synthetics. Synthetic oils carry a detergent factor to them that tends to clean out all the "crud" around seals which will cause them to leak. So, if you want to run synthetic be prepared to change all the associated seals (engine or trans).

Although early formulations of syntheitcs may have caused this, it is no longer true (and hasn't been for a long time)...

I happened to me about 6 years ago. It didn't leak until I put synthetic in the engine. And from experience it seems like everytime I use MTL it leaks. I've even had that problem with the seals were replaced.

[srivett]

If your brother has a 4x4 putting synthetic oil in the diffs, transfer case, and tranmission is supposed to help a fair bit.  I have a van that gets 12 MPG so I just don't drive it.  It's pretty sad that Ford kept making that crap 6-cylinder for 30 years instead of developing an economical engine and sleeker body like Mercedes did.

My 92 Golf with a low compression (360 psi) engine and bull-low transmission burns 6.3 litres / 100 km or about 38 US MPG running between 110 and 140 km/hr (My speedo is atleast 10% too generous).  The engine has 380k km on it and I'm running 0w40 synthetic engine oil and 75w90 semisynthetic gearbox oil.  If your brother buys a car with good compression his mileage will go up.  The cars with reasonably geared transmissions also get better mileage and don't scream on the highway (bigger tires can help).  Also, I wind my car out to red-line in every gear before shifting and can't maintain a constant speed so 38 MPG is pretty good in my book so there's no way your brother can loose money.  

Cheers, Steve

[Centurion]

I run allotta miles 200km/day - Thurs -Friday - Saint John Sat - Halifax Sat night - Sunday night run back in the night - to Fredericton - and back to the JOB.

Mileage is due to alotta things - including gettin into the pedal - I have run 62 mpg running a NA diesel in 5th around the quebec townships - to 52mpg running with the pedal on the floor on the 20 and 401.

I ran - 480km on 44 liters -30.76 MPG  hauling 1000# more stuff and a trailer with 500 pounds of stuff to a market. She ran boost all the time - and I drove her like I was running an old cab over 9000 that I use to drive.

Tall tires - high pressure - low 5th gear - low pinion ratio

and oils all help

Cheers - Centurion

[vwmike]

I just checked my mileage and I'm getting 39 mpg....that sucks. The truck does smoke, so I guess it's just got more fuel than it can burn. I think most of the problem is when I shift it down into 3rd on the freeway to try and keep the speed up around 55-60. The speed limit is 60 most everywhere, so I normally drive in the 65-75 mph if I have a vehicle that will actually do that on a consistant basis. I got it up to 75 once...going downhill....with a tail wind.