Synthetic engine oil makes less power?

When changing oil from one type to the next, did you do any cleaning to remove the previous oil? I don't know about royal purple, but Amsoil suggests a cleaning agent be run through the system prior to changing to Amsoil. At least that is what I remember from my early days of using Amsoil. I changed all my vehicles to it years ago to avoid the 3000 mile change routine. I run 10000 miles each change more or less with no problems other than maybe adding a quart occasionally. That comes from parking nose down so that measurement with the dipstick is less than precise.

When I drained it, I drained the oil pan, cooler and filter. But didnt use anything special.

What were the brands and weights of the oils? Were the oils you tested RACING oils? Was that 2 or 3 degrees or 23 degrees? What was the actual temperature? What was the gross amount of horsepower that your motor was making? What RPM range was this engine running at? Was it dry sump or wet sump and did it have the same volume of oil for each test? I am curious about your findings. Us average Joes dont have a dyno to test all this stuff down to a fraction and we have to take the oil companies claims as fact......Most of these minute amounts of power cant be felt by seat of the pants testing so who knows? Most of the claims I here are about opposite of you findings,and thats at a bazillion rpm. I guess the main thing to remember is the First Commandment of Motor Oil is "Keep if full of something".......

It might be useful to check flow rates (comparing time required for a volume to drain out of a container with a small hole at the bottom at or near working temperature) of the two oils pre- and post-test. This should give you an idea of any difference in kinematic viscosities and should be easy to set up if you don't have a viscometer.

When you say you 'kept the oil and water temps with-in 2-3 degrees', how specifically were you managing these? My guess is that the variation results from either a difference in viscosity or the used to keep the temperature within 2-3 degrees.

True synthetics; developed in a lab do not blend with conventional petroleum oils at all, unlike the sort such as Mobile One which is developed from conventional oil which does blend.

Use of Amsoil requires draining then cleaning with their recommended recipe to effect lubricity as advertised.

You shot yourself in foot; follow directions...

Has anybody taken into account the accuracy and repeatability of the dyno in question. If you run the same setup multiple times you probably wont get the exact same readings. The weather plays a big roll in an engines output as well.

I have a feeling that this testing was not done quite accurately enough to believe the correct readings.

I have been a user of Synthetic and part synthetic oil for about 19 years or so, of all the cars used since then, new, second hand and company cars, I never had any damage to any of the engines, except the diesel engine that my wife tanked up with petrol before going on a fast run on the autobahn, it needed a new head, but the block was fine.

It blew out all the cooling water......she filled up with diesel (on my orders) added a pint of engine oil to the tank, topped up the cooling water and drove home, in spite of two splits on cylinder head between inlet and exhaust....I am sure that the synthetic oil saved the rest of the engine.....

As It did to another car where I had been give Agri-petrol instead of Super......in Italy. The engine ran a further 100,000 odd Kms, till we sold it with NO repairs other than filling with Super (It used normal petrol) to offset the Agri-petrol in that bad tankful.....

Also, I had exceptionally good fuel mileage (for the car/year) from both the petrol engines (3) and the diesel engines (6).....although this has probably more to do with the driver than many others accept......I also get extrememly good mileage from my tyres and brakes.......not that that has anything to do with this blog, sorry!!

Changes in barometric pressure can easily account for the power variations you observed. Did you accurately monitor ambient pressure and temperature? When a weather front passes through around here, atmospheric pressure can change rapidly.

Now the guy didn't say this was a science experiment.

My first question was why was it on the dyno to begin with?

Are the differences simply the rings seating after a rebuild?

The motor was on the dyno because I switched from a carb to fuel injection. The dyno was a DTS Powermark, recently calibrated. The temperatures were controlled by use of thermocouples and adjusting thermostat and cooling fan. Temps were kept with-in 2 to 3 degrees of each other. Water temp was 180F and oil temp was 190F. A base stock 2 oil was used, then Royal Purple and finally Amsoil. Oil lever was the same for each test. All test were done with in a few hours, and weather conditions did not vary by much, correction factor was only different by 0.005. The differences were compared for each oil, and the power and torque were pretty consistant for each run with the same oils.

The base stock 2 has the highest kinematic viscosity of all three. Since maybe the engine is a 5.7 L 350ci "truck" engine, could it be that the "thicker" oil allowed the engine to load more?

You've answered your own question. You'd need use comparable stocks an equilibrium to make ya think.

You seem to have your **it together. I'm glad I found you. This is something that I've been wanting to do for years but just don't have the means.

The time, early '70's. The vehicle, '69 Roadrunner 383 4 speed bought new, then with about 50,000 miles on it. Heavy into street performance. Knuckle marks in the dash. Flat shifted, almost never missed a shift.

I always used Pennzoil 10-30 (a report from Texaco, on a test of New York City cabs, found 10-30, Texaco in this case, to produce the least wear on camshafts, who am I to dispute that). I wanted to start adding Rislone due to my understanding that it was composed of molecular, not particulate, molydisulfide, and wanted to make some sort of definitive test.

Before changing the old oil with 3000 miles on it, I took it, leaving the house with a cold engine, to a secluded section of highway about two miles away and made five hard runs at consistent shift points, starting from a particular spot and ending as I went under a bridge. All runs were in the 100 mph range. Then went home, changed oil and filter and added four qts of oil and one qt of Rislone. The distance to the highway was about two miles, so I figure all the oils were reasonably mixed and at a similar temperature to the first set of runs. The next five runs showed a consistent increase of three mph. Yes, this wasn't scientifically controlled with temperature, pressure, and correction factors, but it sure impressed me. 3% actual performance seems to exceed any error factor, given what circumstances I tried to control. (I was involved in jet engine testing at the time, so I had some idea as to variables)

Since then, I've kept an eye out for an opportunity to accurately run this test on a dyno. It seems that you might have the ability and a similar interest in doing this type of test.

I was trying to figure out what oil would give me the most power and torque. I've always wondered about Royal Purple's claim that all you have to do is use their stuff and get extra power. So I chose the three different oils to make an experiment out of it.

Seems to me that you have done a good job with your testing. Maybe it's just the difference in viscosity of the three fluids and the oil pump takes 6-7 more hp to pump the synthetics?

It also seems that should trust the data and go with the conventional lubricant.

I don't think you are concerned with change interval, just raw power.

Good Luck!

Where do get the data concerning sump & pump using more hp with synthetics?

Take a look at the original post. What other conclusion could one have made?

One variable, the oil.

From the data presented, the only thing that changed was HP output produced with each oil. The oil pump is mechanical and will require more power to pump a higher viscosity fluid at the same volume output.

I have no idea what the relative viscosity, resistance to shear, of the three fluids really is.

Just my idea.

The second post from the OP states the higher viscosity oil was the conventional type

You have just given me an idea, many thanks.

The idea is simple, far too simple really, but conventional oil gets thinner the hotter it gets, synthetic is far more stable, which is why the engines using it last longer.....bearings are not as well protected in daily use with conventional oil....

The thinner conventional oil does not load up the oil pump as much......therefore more power.....not much when one looks at the possible power of that engine......1 or 2 % difference? Simply not worth worrying about in comparison to the extended engine life....

You're welcome.

I thought his test was elegantly simple.

He's going for power, not economy. At 1,500rpm the synthetics might give 2% more mileage/economy, who knows.

The manufacturer will test under the ideal conditions and parameters to support his claim.

One idea I had was the conventional oil, with the higher kinematic viscosity also had a high viscosity index. For a conventional oil to have a high index, it must contain alot of viscosity index improvers, polymer chains that contract at low temperatures and expand in higher temperatures to change the "thickness" of the oil. The conventional oil had a low high temperature/high shear number, meaning it sheared more easly in high temperature and shear conditions. So maybe this meant the polymer chains (viscosity index improvers) were sheared and in doing so "thined" out the oil because those polymer chains were no loner streched out to keep the oil "thick".

You may be on to something here. I can't help.

We've never established what your oil change interval is and how concerned you are about wear to moving parts.

I get the impression that you'd rather have the 6 HP. Your test shows you how to get it.

This is a drag race engine, so not really concerned about wear. But I was just curious about the different oils while I had it on the dyno.

What would happen if you took .020" (substitute your number here) off the OD of the oil pump impeller and ran synthetic?

Crazy, I know.

Risking alot modifying a $30 part to support the engine

If an engine is cooked would it still run and if it was slightly under done what problem would you be getting?

We only did that once

Pay particular attention to foaming.

I've switched from amsoil to the NAPA full synthetic, greater variety and cost is lower too.

Keep in mind the oil temperature, conventional oil if kept above 230°F for a very short time loses it's lubricity but the lubricity of synthetic is not effected by temperature.

Many years ago I did some testing of high performance engine oils and though much has become available since the results still hold and remarkably the shell oil 10-50wt is a very effective conventional product. When racing we generally used straight 50wt but the engine was pulled, tanked and rebuilt for each race too. The 50wt would breakdown to less than a 5wt when the 10-50wt would shine on...

All this talk of horsepower but nobody has even mentioned torque. Do you know what the difference in torque is between the different oils?

There was a 6 HP and 4 ft-lb differences in the convential and synthetics.

What RPMs and HP and TQ were observed and exactly what oils?

Using Mobil One 10-30 is one of the few things I have done that increased my mileage. Not a racer, but just under 300HP with a Chevy 350 in a lowered pickup.

-Exxon conventional 10W-30

394.5 ft-lb @ 3600 RPM

306.2 HP @ 4500 RPM

-Amsoil Dominator 10W-30

391.5 ft-lb @ 3600 RPM

302.7 HP @ 4500 RPM

-Royal Purple 10W-30

389.4 ft-lb @ 3600 RPM

301.9 HP @ 4500 RPM

Interesting and seems to fly in the face of other testing which concludes that use of synthetics generally increases fuel economy 5%-6%.

Did you correllate cylinder head & cylinder wall temperatures too?

http://www.amsoil.com/lit/databulletins/g2569.pdf

According to their information, it's an oil recommended for high RPMs. I don't consider 4500 all that high. I think a standard grade Amsoil be a better test oil at those RPMs.

Could that be part of what was observed? Maybe the oil performs better or has better properties at 6500 or 8500, but not as good at lower RPMs?

I know that racing oils are not good, nor recommended for use for non racing uses. They are designed for high RPMs and frequent changes............... something that is expected in racing oils.

I didn't use the in-cylinder pressure or temperature sensors when it was on the dyno, but I the higher RPM range was considered but the engine I was testing didn't make enough power up there to even look at.

After all the discussion, I am able to reiterate some points:

1- You did a nice job. Trust your data.

2- Do not believe in everything you see in advertising or TV shows...

3- Certain products are never absolutely better than others to do everything. There's always one thing that is better than another to do something under determined conditions.

I have read automotive magazines for the last 45 years. It seems to me that when a mag was trying to wring as much power out of an engine as possible, Royal Purple was an item that always seemed to bring another 5-15 HP out of an engine. I will try to find some of those tests to quote on this site. I hope the criteria used on those tests will help to shed some light on your dilemma. Good work on your part for an accurate test.

You have made a very good START at obtaining comparative data. No dyno setup is capable of +/- 1% repeatability (which is what your data are) even on back-to-back runs at 'identical' atmospheric conditions. Your data says 'the measured horsepower appears equal within the precision and accuracy capability of the measuring equipment.'

It is very common to misunderstand the inherent errors in measurement and interpreting the measurement. The computer data logger will present very PRECISE output, but that precision (to the tenth of a Hp?) does NOT mean ACCURATE. A far more realistic output would be 297.5 +/- 3%. or '297 +/-10, 95% confidence level.'

You would have to perform LOTS of experiments on the dyno to develop precision and accurracy inherent in the system. Each component that measures or controls anything has an inherent range of precision and accurracy. They may be additive or subtractive in any particular measurement set.

Once the measuring system precision and accurracy and repeatability was nailed down (a minimum of 50 truly identical runs) to hope to get within 3% probably, you could then begin running random order replicate tests of the 3 oils--for a minimum of 10 each. Then using appropriate data analysis techniques, you could develop a probability curve for each oil (3 'bell shaped curves') plotting the max Hp vs probability. I suspect you would find a very low probability of there being a statistically significant difference between the oils.

Having very good personal experience in lube oil manufacturing and formulation, and similar experience in gasoline,turbine and diesel fuels, I am continually amazed at the gullibility of the motoring public.

People will spend $30,40,50,000 on a vehicle and then hunt for the cheapest gasoline, or drive way too long between oil changes. Remember, the manufacturer is doing everything reasonable to make sure the vehicle gets through the warranty period without failures, then soon dies from very costly failure.

I'll check on the repeatability of the dyno, but from what you're saying even making pulls back to back with the same oil wouldn't be able to produce +/- 8 to 10 HP? I know the last digit is not trustable but from what you are saying I cant even trust the next to last digit? While tuning the engine I make close to 50 pulls and once I got it where I liked it, the engine was always with in 2-3 HP.