Measurable fuel economy increase with Delvac 1

Gary Allan · Jul 6, 2003

I recently (about 4k ago ..that's recent for me) changed from Mobil 1 to Delvac 1. My wife's Sahara TJ(68,500 at the time of the change) has always gotten between 17 and 17.5 mpg. I check it virtually every fill up. Since the change over I've broken 19+ a few times and am consistantly at 18.5. Now I've used Mobil 1 from around 2500 miles in its various formulas (I had a fondness for the 0w-30 ...but the local stores just don't keep it in stock) but have never observed any fuel economy (I guess it would be hard with using only one oil - you only know if you switch to something different).

Just figured that I'd share the observation. I'm going to do a 10k UOA on this jeep with Delvac 1. My last UOA at around 9k the oil was about shot. I wish my Wally World carried the stuff ..but alas ..they only carry the 1300 (yes, only the Delvac 1300 - I even asked the guy stocking the oil).

buster · Jul 6, 2003

Thanks for the info. What oil were you running before that was shot?

Gary Allan · Jul 6, 2003

Mobil 1 either SS or Tri-synth. I had stocks that I used during a 6 month filter change. I was rather disappointed with the UAO results ..not so much for the wear metals (I had a slightly evevated lead level which is apparently normal for my 4.0) ..but the oil was down to 2.5 ....and this was with a 9.5 quart capacity with a 4 quart make up after the filter were changed. So ..even adding 4 new quarts of oil ..it was shot.

I'm hoping that Delvac 1 holds up better.

Jay · Jul 6, 2003

You may see an increase in mileage if you switch from 15w-50 to 5w-40 but not if you switch from any of the 30-weights to 5w-40. Your gas mileage increase is measurement error or some other factor like tire pressure, change of season, etc.

quadrun1 · Jul 6, 2003

One of the regulars over at the SAAB forum observed the same thing with his 900SET--increased fuel economy with Delvac 1 over M1.

Gary Allan · Jul 6, 2003

quote:

Your gas mileage increase is measurement error or some other factor like tire pressure, change of season, etc.

Nope ...sorry. I am REALLY ANAL about gas mileage. As I said ...I calculate it virtually EVERY fill up ...and this is since we bought it in 99 (or 73,000 miles ago). I do this with every vehicle I own. It's how I base engine (tune, etc.) performance. I've done this since I've had a car with a trip odometer.

This vehicle is my wife's daily driver. She commutes 50 miles round trip 4 days a week. It's routine has virtually not changed in the 4 years that we've owned it (hence the 74k in 4 years).
Under your assumption ...I would have had the same errors in the multitude of previous calculations. As I said ..I've had an almost perfect 17-17.5 without any further variation. One would reason that if those factors that you mention were in fact factors at all ...they would be apparent throughout the vehicles history. That is, I would get 16.5 ..15.5 ...18.0. In fact I can even say that when this vehicle has been filled ...that I've done it with very few exceptions. My job takes me by very cheap fuel. Once a week I take the Sahara to work. I fill up in the same Hess station ...and usually the same pump (since the thing doesn't fill up all the way if you aren't tilted slightly downhill).

Normally I would agree that there it would take more energy to pump a 5w-40 over a 5w-30 ..In my case, however, I'm up against the pressure relief at anything above idle. My aftermarket high volume pump has twice the vane area of the OEM unit. I'm at 58 psi almost all the time. That is, I'm already cosuming more energy than I should for just pumping the oil through the engine. Since any excess "weight" from one oil to another would just mean that more or less is shunted back to the suction side of the pump (or the sump) ...those hp consumed should be equal regardless of the oil I use.

This is the "real deal".

Intelman34 · Jul 6, 2003

Delvac 1 is definetly a good oil!

My father has noticed an increase in gas mileage using it in his 90 Nissan Pathfinder.

vvk · Jul 6, 2003

It's not Delvac 1, it's the 40 weight. Try any other 0/5/10W-40 and you will see similar numbers. I got about 10% improvement when I switched from 10W-30 Mobil 1 to 10W-40 Chevron Supreme.

spinfire · Jul 6, 2003

quote:

Nope ...sorry. I am REALLY ANAL about gas mileage. As I said ...I calculate it virtually EVERY fill up ...and this is since we bought it in 99 (or 73,000 miles ago). I do this with every vehicle I own. It's how I base engine (tune, etc.) performance. I've done this since I've had a car with a trip odometer.

You think you're anal, check this out:

http://isomerica.net/car/mileage/full/

Amazingly, I know people who are even more anal about keeping track

Gary Allan · Jul 7, 2003

quote:

You think you're anal, check this out:

http://isomerica.net/car/mileage/full/

Amazingly, I know people who are even more anal about keeping track [Smile]

I beg your pardon

What was I thinking?

I can see that I'm only a plebe in the "anal about gasmileage" club.

I yield to the higher authority

ToyotaNSaturn · Jul 8, 2003

Newbie question: how can heavier weight oil aid in increasing fuel MPG? If it does, then what's the big deal behind the latest rage of manufacturers using 0w-20??

Ken2 · Jul 8, 2003

A higher viscosity oil will hurt gas mileage. A different brand of oil might have better friction modifiers or other reasons for better fuel mileage due to less friction in the engine, and even a heavier vis of the new brand might show lower fuel consumption, although it's unlikely.

Ken

boxcartommie22 · Jul 8, 2003

pscholte, i live in littleton you can get delvac 1 at jiffy lube on south wadsworth right next to cub foods...just go north on i 25 and exit onto c470 west get off at wadsworth and go north i think about 5 miles... cub foods is on the east side can't miss it...

Gary Allan · Jul 8, 2003

quote:

A higher viscosity oil will hurt gas mileage.

Yes ..but ONLY (IMHO) for the energy consumed to pump it through the engine. That is, a 0w30 is going to require less energy to be pumped through the same engine then 15w50 ...

...but what if you're already at the MAXIMUM flow that the system can handle ..that is ...you are at THE MAXIMUM pressure that the engine allows? The ONLY difference between a 0w-30 and a 15w-50 at that point is how much is sent back to the sump and doesn't go through the engine. You consume the same energy ...the only difference is the GPM flow.

Ron · Jul 8, 2003

Hi,I'm currently running D-1 in my '99 Ford E-150 van 4.2L six.Now after 3k miles,I can't see better fuel economy.It does show

less oil consumption than Castrol Syntec 5W-50.

pscholte · Jul 8, 2003

Where do you all get your Delvac 1? I live in Colorado Springs and am not sure I have ever seen it on the shelves at Autozone, Pep Boys, Advance Auto or Checkers Auto. I would like to try it in my sons '94 Nissan Hardbody (111K) and based on what I have seen here I recommended it to a neighbor who is getting a (relatively) new VW Jetta TDI.

Thanks in advance.

Jay · Jul 8, 2003

quote:

Originally posted by Gary Allan:
..Yes ..but ONLY (IMHO) for the energy consumed to pump it through the engine. That is, a 0w30 is going to require less energy to be pumped through the same engine then 15w50 ...

...but what if you're already at the MAXIMUM flow that the system can handle ..that is ...you are at THE MAXIMUM pressure that the engine allows? The ONLY difference between a 0w-30 and a 15w-50 at that point is how much is sent back to the sump and doesn't go through the engine. You consume the same energy ...the only difference is the GPM flow.

Every moving part lubricated by the heavier oil will have higher friction associated with it. It's not just higher oil pumping losses, although those will be higher too.

James Chow · Jul 8, 2003

I recently switched from dino 10w40 in one vehicle (145K mi) and from dino 5w30 (14K mi) in a new vehicle to M1 Delvac and noticed a mileage increase. The best I got on the highway w/ the older vehicle (flat, 68-72mph, no A/C, sea level) was 22.5-23mpg. With the M1D, I'm getting 24mpg (flat, same speed, A/C on the entire time, 2K-3K ft alt.). In the other vehicle, mileage increase was more difficult to acertain since driving cond's are different (prev. was freeway at 70mph, 27mpg, but on MTBE gas; new driving is 50-55mph, 32mpg, non-MTBE gas). I figure the slower speed will account for 1-1.5 mpg, non-MTBE gas another 1-2mpg, which would suggest the M1D accounts for the other 1.5-2mpg.

BTW, is there any reason not to use M1 Delvac in gasoline engines all the time? (other than the price?) It's certainly more convenient to use the same oil in all of my vehicles, but I was wondering if there are any negative effects? Would the engine life be as long as if I ran M1 0w40?

[ July 09, 2003, 01:48 PM: Message edited by: James Chow ]

Gary Allan · Jul 11, 2003

quote:

Every moving part lubricated by the heavier oil will have higher friction associated with it. It's not just higher oil pumping losses, although those will be higher too.

I don't agree with that assertion. Under that criteria ... light cutting oil would provide the finest friction free medium to lubricate your bearings with. An extreme example ...but your statement is too "all inclusive". I also don't see, other than "windage" (which is allegedly a thing of the past in modern engines) and the aforementioned pumping losses, how a heavier weight oil adds to friction ..or even a more appropriate term "resistance".

The ONLY reason that lighter weight oils were introduced was to reduce the energy consumed to pump it through the engine.

Measurable fuel economy increase with Delvac 1

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