Oil additive testing
 

I'm running a series of tests of an oil additive to try and measure the effect of engine operation. This is based upon measuring the fuel consumption of the engine at idle during warm-up and idle during cool-down. So far, I've only been looking at warm-up fuel burn.

The protocol is to start the car and shift into "N" a few seconds after the engine is running on its own. I'm using our 1.5L, NHW11 which shares the same engine as the NHW20 and AutoEnginuity to record the data:
http://hiwaay.net/%7Ebzwilson/prius/warm-up_010.jpg
The key data are: coolant temperature, engine rpm, ignition timing and mass air flow (MAF). There are four useful records:

#2 - 0W-20, Mobil 1, 8k service miles, 2 quarts were drained including filter
#3 - 5W-30, Mobil 1, 0 service miles, 2.5 quarts were added
#4 - 5W-30, Mobil 1, ~150 service miles
#5 - 5W-30, Mobil 1, ~150 service miles, added 8 oz additive and 8 oz of 0W-20 to rinse container

One unexpected result is two tests starting under 12C changed the ignition timing from 10 to 5 degrees about 660 seconds into the test. In contrast, two tests were the starting temperatures above 20C kept the ignition at 10 degrees. This suggests at colder temperatures the spark is retarded which would increase the exhaust gas temperature because less work is extracted from expansion stroke. But we are interested in the oil additive.

The next charts compare the new oil versus the same oil with the oil additive:
http://hiwaay.net/%7Ebzwilson/prius/warm-up_020.jpg
There was an offset in the spark reduction to 10 degrees offset due to the 11C difference in starting temperature. Furthermore, as the engine ran, the lower heat loss due to warmer ambient temperature means then engine warmed up a little faster.

Increasing the Y-scale, show nearly identical MAF profiles except at the end where the virgin oil suggests a slightly lower fuel consumption compared to the same oil treated:
http://hiwaay.net/%7Ebzwilson/prius/warm-up_030.jpg
However, the oil additive instructions report that the additive takes a while to coat the metal surfaces and it suspends gunk and varnish:

"If used when you change your oil, simply add with any premium oil. If used between oil changes, add to engine at least 1,000 miles before your next oil change. This will ensure sufficient time for boundary layer formation and bonding. Add directly to crankcase when the engine is warm, then run engine approximately five minutes."

"This treatment will remove sludge and varnish from your engine. When used in engines with over 100,000 miles, change the oil and replace the oil filter after 1,000 miles to eliminate these contaminants from your engine." - additive instructions on side of box

To investigate this further, the time line was offset so the first ICE rpm drop starts at the same time reference:
http://hiwaay.net/%7Ebzwilson/prius/warm-up_040.jpg
The plateau of the ICE coolant occurs when the thermostat opens up allowing the rest of the coolant to flow through the engine block. Once all coolant is at the same temperature, warm-up continues.

Changing the Y-axis scale, we see the ignition advance change occurs concurrent with the engine rpm reduction:
http://hiwaay.net/%7Ebzwilson/prius/warm-up_050.jpg

Again, increasing the Y-scale, the MAF lines are all but on top of each other:
http://hiwaay.net/%7Ebzwilson/prius/warm-up_060.jpg
There is no evidence that treating the oil had an effect during a cold-start, warm-up. This raises a question of whether or not we could detect any difference in oil friction effects.

To test the test, we compared the 0W-20, 8k service miles to the virgin, 5W-30 oil. Changing the time scale to align inflection points, we find a consistent gap between the used and new oil during warm-up:
http://hiwaay.net/%7Ebzwilson/prius/warm-up_070.jpg
This data set provided ~2,400 samples showing the lower fuel consuming 0W-20 with 8k service miles versus the stock, 5W-30 with 0 service miles.

Mapping the relative ratios we find the 0W-20 has about a 2% reduction in fuel consumption versus new 5W-30:
http://hiwaay.net/%7Ebzwilson/prius/warm-up_080.jpg
Good Prius friend, David Kelly, found a reference that 0W-20 has about 2% lower internal friction than 5W-30.

The oil additive instructions require 1,000 service miles before a second oil change to remove the varnish and gunk it releases from older engines. At that point, it should have coated the moving parts with a low friction layer. But 1,000 miles exceeds the tank capacity of our NHW11 so I'll have to run gas reference tests before and after each tank. Otherwise, there is a risk of measuring a change in winter-summer gas energy content and not the oil additive effect. Also, I didn't add the oil to a 'hot' engine so I may use the second oil change to add the remaining 8 oz.

Bob Wilson

I'm going to be "testing" Motorsilk in auto trans...engine...and gas maybe this month. As you mention...the additive is supposed to be added to a warm engine in new oil and run for at least 5 minutes? Considering the cost...I'll be using a flush in the old oil and changing in new oil and filter...then driving around for an hour or so after adding it.

If you have a higher mileage engine (over 100K)...they recommend changing out the oil filter after so many miles...saving and then re-adding this oil...if you think the filter might be getting clogged....but not putting in new oil which removes the additive.

If I were to test with the data you're getting....I'd test vs the same weight and brand of oil and give the additive a few K miles to deposit itself before testing. And I'd compare GPH after warm up.

* saw your testing protocols after posting this...I just do "cumulative mpg testing"...I try stuff I think might work and see if my mpg gets better....none of that A-B-A stuff for me....

A bit of a joke, perhaps you might wait until the fall to run your test? The reason is as the cold weather arrives, an effective lubricant will mitigate the temperature and gasoline change.

Actually it maps back to my first Prius bought in October 2005. My earliest studies in fuel efficiency occurred in the late fall and early winter. Talk about a challenge!

What I did was top off the tank twice a week, Friday evening and Sunday evening. This allowed me to separate commuting-style driving versus weekend-style driving. Then I could quantify various effects and know what worked and didn't work:
http://hiwaay.net/~bzwilson/prius/epa.jpg

Bob Wilson

Well...I'd rather test stuff when the weather is getting warmer and they switch to summer gas (end of April?). ;)

I'm doing the Motorsilk in the auto trans along with flushing in new synth ATF...having already done a partial flush with regular ATF from the original ATF with over 100K miles on it. Not exactly controlled testing. But I'm doing all this as much for longevity as mpg gain.

Through all this my driving at least remains more or less consistent...keeping revs around 1750 to 2000 for the most part. Top speeds 45 to 50. With the auto...you see an mpg jump when it shifts into 4th at 40 mph and locks up.

Seeing the nasty effects of too many stop signs and slow downs for curves etc....so maybe I just quit stopping and slowing down? :thumbup: Not real likely....too easy to get t-boned.

I'm hoping to see a gradual avg mpg gain and a stable tank to tank avg of + 35 mpg this summer. Indications are a possible 40 mpg at 45-50 highway.

Interesting graph you have...but what is the part about draining a qt of oil...did you test overfilling by one qt? Or under filling?

In my crude way I was trying to point out that if one wants to show any oil additive (or any other technique or technology) in the worst way, simply schedule the test to coincide with the cold or cooling weather(*). To show them in the best light, test in warmer than a standard day or warming weather.

The reason why I spend so much time in testing methodology is to eliminate these climate effects. I really want to know what is reality, not which way the weather blows.
. . .

When we change oil, some of it remains inside the oil pan and other galleries. But once the new oil is put in, this undrained oil mixes with the new and changes the characteristics from virgin to a mix of virgin and used oil.

What I've done is take three samples with these known quantities:

#1 - old oil, drained 2 quarts
#2 - virgin oil
#3 - added oil, 2.5 quarts, before treatment

I'll get back three oil analysis with about two dozen metrics. Then using partial fractions, I can calculate what percentage was left in the engine:

X#3 = (n-1)*X#1 + (n)*X#2

I don't know how much old oil remains in the engine after it is drained but by having three samples, I can calculate the percentage of old to new oil. The only fly in the ointment is the potential of a gunk layer in the bottom of the oil pan. I have certainly seen that in my transaxle oil testing.

I am seriously thinking about dropping and cleaning the engine pan on the next, 1,000 mile change. But I'll have to get a sealant and scrape off the old sealant and that takes time. Still, doing it once every +100,000 miles, sounds like a small enough price to pay.

Bob Wilson

* - Auto magazines did this by trying to run the Prius and other cars in the dead of winter. The "Green Human" faux test tried it too with an 8,000 mile, highway driving test from Maine to Washington State drive only to find at best, a tie. The mileage reported, 40 MPG, indicates they weren't really respecting the speed limit.

Bob, my question is the characteristics of the multi viscosity oil. My understanding is the chemical additive to the oil will change the viscosity as temperature increases. Also this chemical will break down as it is used repeatedly. In this case taking a 0 weight oil to a 20 weight. But as noted, with 8K usage, the chemical break down could effectively be leaving the oil weight at a lower weight than the designed target of 20 weight when at operating temperature.

How are you taking this into effect? Are you measuring the viscosity of the oil at temp? Is the difference really a viscosity comparison of less than 20 to 30 weight? That would not be giving the additive a chance, would it?

This is great information as I'll be applying your findings to my oil choices, no doubt.

These are excellent questions:
My reading of the literature (Machinery Lubrication and a Nora Handbook) says that there are viscosity range extenders. These molecules curl or straighten as the temperature changes to extend the viscosity range. However, they are subject to 'shear stress' that over time chops them up.

That is exactly why I send my oil samples off for testing and pay extra for a 40C and 100C viscosity test. This also gives a viscosity index. Sad to say, not every oil testing service (aka., Blackstone) offers the two-temperature, viscosity test. Ask before sending off your samples.

I needed to know if my test protocol was sensitive enough to detect a change yet I also knew the additive in addition to claimed friction reduction also put a lot of varnish and gunk back in suspension. Suspended varnish and gunk is the liquid equivalent of smoke and increases friction. I am not expecting to see a measurable engine friction reduction until after the second change (and possibly pan cleaning.)

So to test my test, I compared 0W-20 with 8k service miles versus new, 5W-30 and found a measurable, 2% reduction in fuel burn. But it turns out I will also be conducting progressive measurements to monitor any gasoline effects.

This morning I left the NHW11 at home so it will warm-up during the day. By the time I get home, it should be in the mid-70s so my warm-up test will give good data. I will then fill-up the tank and drive enough to burn out the gas in the lines and park the car until tomorrow when I'll repeat the warm-up test.

You are welcome and that is what I so admire about Ecomodder, applied science.

Bob Wilson

I can appreciate serious testing, but don't have the patience for it myself.

Some time ago A guy who repaired and modified a lot of Nissan vehicles was using ZMAX additive in engines as a cleaner...he found that there was some serious risk of sludging up the engine using this additive to the point he recommended pulling the pan to clean it and the screen.

I think Motorsilk might do something of the same thing, but I'm too lazy to pull the pan...but will run a quart of Gunk 5-minute engine flush for 10-15 minutes idling before changing the oil and adding the additive...and will probably spring for another filter after maybe 1K miles or so...and finish out at least 3K on the additive.

Seems that some people who have used MS find it takes some time to see an mpg gain...due to the sludge released?

My approach is to use lighter weight oils and use extra additives to try and make up for any loss of lubricity.

A very timely post:

http://hiwaay.net/~bzwilson/prius/warm-up_090.jpg

This is the last of the previous tank of gas and initially the warm-up idle MAF rate at ~2.6 gm/sec, nearly 40% higher, compared to ~2.1 gm/sec looked terrible:

http://hiwaay.net/~bzwilson/prius/warm-up_100.jpg
http://hiwaay.net/~bzwilson/prius/warm-up_070.jpg

But I also noticed the engine rpm did not drop to under 1,000 rpm as it had in previous tests. I was pretty quick in shifting into "N" and this may have had an effect on the idle speed. Regardless, the cool-down MAF rate, ~1.9 gm/sec, this is much closer to earlier observations.

If I had just gone by the fuel consumption and not paid attention to the ICE rpm, I might have aborted the test thinking varnish/sludge effects. I'm still going to be watching this closely but I'm not quite as concerned as the initial data suggested.

I have to run another test this afternoon. This time I'll give the car a few more seconds before shifting into "N" and repeating my earlier drive.

Bob Wilson

I cleaned the pan and put in a new filter and flushed in in 6 qts synth ATF and the 10 oz of MS trans additive.

Old ATF was still dirty even after dropping the pan 2xs previous and around 3 qts regular ATF added each time...along with a filter the first time.

The MS additive had no solids in it...looked like thin ATF...no need to shake it. Might be like the Lubegard ATF additive?

As far as the engine sludge with ZMAX...he showed pics of one engine....as I remember it was a heavy sludge in the bottom of the pan...with some partially blocking the pickup screen. But I think this was a turbo engine. I'm doubting that na engines that don't typically have a problem with sludging will have too much of an issue....at least I hope not. Some Hondas might be an exception?