seattle951

I realize that Oil on this bulletboard is like religion but I wanted to share some feedback I got from an an oil engineer from Royal Purple technical support line.

According to Royal Purple's ads, their oil improves fuel consumption, reduces emissions and increases horsepower and torque. They provide a number of studies from automotive magazines and reputable universities. After reading the article, I thought I would give it a try. From their website they recommend 5W-30 for water cooled Porsches and 20W-50 for air cooled Porsches. Because of the diverse opinions on this BBS, I thought I would call one of their engineers and verify that the recommended oil was 5W-30.

The call lasted about 10 minutes and we discussed my modifications and my experience with Mobil 1 0W-40 and 5W-30 and Castro Syntec 5W-50. My car has maybe 5,000 miles since a complete rebuild and runs very cool seldom making it to the halfway mark on the temp gauge. With 0W-40 and 5W-30 oil pressure is just under 3 at idle at operating temperature. The car has an additional oil cooler and my mechanic changed something with the radiator/cooling fans when the engine was replaced. The car also has "Water Wetter". The climate in Seattle is temperate with temperatures mostly in the 40s in the Fall, Spring and Winter. The car has zero oil consumption on any grade of oil even after a full day at the track during a DE day.

To make a long story short, the Royal Purple engineer confirmed the website recommendation of 5W-30 for my car. The mechanic that built the motor has pushed for 10W-30 synthetic since installation and scoffed at the idea of running 15W-50. He just didn't feel that the car was running hot enough to justify the thicker oil. He recommended only synthetics because of the turbo.

Anyway, I am going to give RP 5W-30 a try. If anyone is interested, I will report back with my opinions.

Out of curiousity, does anyone believe the claims about improved mileadge, lower emmissions and more power from the RP website?

Duke

Claims about improved mileadge and power always comes from comparisons between the company's lightest oil (like the 5w-30 or 0w-30) and a competitors thicker oil.

Claims about heat and bearings etc. always comes from the reverse.

I think many of the street users are running too thick oil. An occasional burst at WOT for 5-10 seconds every now and then doesn't require a super thick oil.
But if you have an extremely tuned machine and/or running it hard at the track a heavier oil is good.

As usual in life there is always trade-offs.

JonH

Out of curiousity, does anyone believe the claims about improved mileadge, lower emmissions and more power from the RP website?

Doesn't every bottle of oil say this? There are tests out there that show some differences in oil "power" but I think you're talking fractions you won't feel.

cruise98

I would believe improved mileage and lower emissions if you were switching from dead dinosaurs to synthetic, but have a hard time thinking you will notice any difference between Mobil 1 and RP. The lighter oil should reduce frictional and pumping losses somewhat.

Buckaroo Banzi

It's the only oil I have ever tried that lived up to it's claims.



-BB

seattle951

The studies on the RP website are with identical weight oils. One of the studies compares 5W-40 Shell, Amsoil and Royal Purple. This study was done by a university and funded by a state government that was evaluating oil recommendations for fleet vehicles.

Royal Purple claims to have proprietary technology that better smooths surfaces and creates an oil film that adheres to metal surfaces better than other synthetics. This is where they claim the benefits come from. Fact or Marketing?

944obscene

I'll have to talk to Charlesworth and see what he recommends. I always stuck with Amsoil, but I didn't feel comfortable running it in a 944 until I found evidence that it wasn't harmful to the motor in any way. Also, before running an oil, I intend on talking to as many different people possible to find what everyone tends to like/dislike. Not only will I talk to Tom about what he likes and doesn't, but I'll ask him about some fluids he's developing. He can't market anything because he's still on the PCA board, but he wants to try some in my girlfriend's 928 when he releases it.

TurboTommy

Their "proprietary technology" is probably the higher levels of moly in their formula as opposed to other oil companies. A virgin oil analysis cuts through the proprietory part somewhat and you can see for yourself. Molybdenum is supposed to coat the parts much like higher levels of zinc and phosphorus. This is a good thing; but don't know how it would work in all different engines and cylinder finishes, etc.
Redline is another company that uses even more moly. Both of these oils are some of the best out there, and I've heard testamonials of increases in performance (don't know of much that is imagination, though).
I'm also one of those that think people, here, are probably using thicker oils than necessary. They panick when they see the pressure gauge a little on the low side. Oil flow is what lubricates parts, not pressure.
Thinner oils flow better and as long as you have the proper film strength, you're golden. The film strength of todays thinner oils are stronger than the 20W50s of 15-20 years ago.

seattle951

At $13/quart it is twice as expensive as Mobil 1. I purchased a case of XPR 5W-30 on-line from their racing oil line. The local shops only stock regular RP.

Since we are on the topic, is there a preference when it comes to oil filters? I have a case of K&N filters. Is there something better?

333pg333

According to the Owner's manual, you can use 20w/50 in temps down to -10 degrees. Sure you might get a few extra miles per gallon by using the very light w oil. The downside to the very light oil is lack of protection that the thicker oil offers. Oil is not just lubrication, it acts as a buffer between the expen$ive moving parts. The thin oil won't give the same protection, especially when hot. I know where I'd rather spend my extra money on.
Look up Charles Navarro in here and read the truth.

seattle951

Better protection at what temperature? Royal Purple does recommend 20W 50 for air cooled Porsches but not for 951s. In their view, 951s do not get hot enough on the street to hit the sweet spot for 20W 50 oil. I specifically asked about about 20W 50 and the technician's response was "overkill" for my application and not a good fit.

If you believe the Royal Purple marketing material, RP's XPR provides 400% to 700% stronger film stregnths than other synthetics. This is the buffer you are referring to in your post. If RP XPR 5W 30 provides greater film stregnth across the 951 temperature operating range than other manufacture's 20W 50, wouldn't it provide more protection, not less?

Oil has changed quite a bit since the owner's manual was published in 1985. As TurboTommy pointed out, a modern lightweight oil will outperform a 1985 vintage 20W 50 at high temperatures.

As I started this post, oil is like religion on this board. There are different opinions and people trust different sources of information.

Chris White

20/50 is needed for track use in most 951s. The oil temps with the stock oil cooler will get way up there (280+).
Its overkill for street use but not for track duty.
A 951 will run high oil temp than a 911 on the track - so Ithey are getting that part wrong.

seattle951

During the consultation he asked me about street or track use. Since I responded "street" he recommended the lighter oil. If I had said "track" he probably would have recommended a heavier oil.

333pg333

As you say it is opening a can of worms, however I don't have the breakdown of the oils your referring too so I can't comment with any authority. You can search on the 996 boards (I think?) or just search Charles Navarro. Look for ZDDP content.
Also the Owners manual even up to the 996 states 20w/50 across a wide range of temps. It's not just the air or watercooled nature of the engines that determines what oil to use. There is a lot of history of worn engine components when people switched to the synth low visc oils like M1. Engines were expiring in a very short period of time relative to what went before them. The same shops switched back to a thicker dino oil with ZDDPs and hey presto problem solved. Too often for it to be coincidence.
I'm not saying that you can't use that oil. Hell some people even prescribe Truck or Bike oils. For me even when I'm not on the track, I like knowing that I have that protective 'film' you mention. There's no way in hell that 0w/30 is going to give me that same level of protection no matter what it says on the label. Horses for courses as well.

seattle951

Would you agree that the critical variable here is film stregnth within the operating temperature range of the engine?

Is it a reasonable assumption that a 5W-30 could have the same film stregnth as 20W-50 at certain temperatures (lower temperatures)?

Does it make more sense to focus on optimizing film stregnth rather than a specific weight of oil?

Once again, my position is based on accepting the Royal Purple input as fact rather than marketing hype. They promote their proprietary Synerlec additive as a game changer in terms film stregnth and adhesion capability.