928 79 SLC

My '79 needs its oil changed...I'm thinking about switching to royal purple...a friend of mine who has a '86 Z swears by it...any 928 driver's out there using this oil...all thoughts and comments are welcome

IcemanG17

I'm very happy with amsoil.......but I haven't tried Royal Purple either

Ed Hughes

RP gets a fair amount of respect in the automotive world. Redline too.

anonymousagain

Enzo...opinions on RP thus far?

Daniel Dudley

Also Mobil 1 20/50 high performance with the SL, SM rating. As has been noted elsewhere, this is suitable for all early Porsches, and is available at Wallmart. Kind of like the ''Classic'' version, but not exactly.

No one has ever bad mouthed Royal Purple, and I've looked. Go for it.

They do say with the Red Line that you use 10/40 instead of 20/50, as it is the equivalent of normal 20/50. That is from the factory website.

bronto

Not to hijack "928 79 SLC"s post, but I have similar questions. I know that this has been hashed and rehashed over and over, but it seems that everyone's experience is different depending on model and weather.

Engine oil hasn't been a noticeable issue for me until a couple of weeks ago when I drove through the Bakersfield/Fresno area during high heat (100+). When at idle, oil pressure got scary-low (1 to 1.5 bars) and at times when at stop signs the engine would idle very low and die; the warning light would come on too but I'm not sure if this was before or after the engine died (I started giving it a little gas at stop signs after that). Not quite certain what my wrench put in it last time, but I think it was Valvoline 20-50. OTOH that might have been left over from my last purchase.

Similar to this is that I need to change my transmission oil. I have a 5 speed with LSD. I am certain that whatever I have in it now doesn't have the LSD modifier in it.

Driving conditions related to both engine and trans oil: I live in a moderate climate where daytime temps rarely go over 90 and nighttime temps only occasionally go lower than 40. However I do make occasional trips above snow level in the Sierras in the winter (20 degrees?) , and to the Fresno area in the summer (110). Engine oil hasn't been an issue until the above trip; the transmission in normal driving around home is typically "notchy", but more notchy than when I first brought it here (and prior to changing to oil without the modifier). In winter here (low 40s) 1st gear is barely usable. In the Sierras it's completely useless until at operating temp. Never noticed an issue with heat.

I'm willing to go Redline or Royal Purple if I can find a convenient distributer, which is no lock here in Santa Barbara.

Suggestions?

Chuck Schreiber

Guys,

I've used RP 20-50 in the 79 my last 2 oil changes and it's performed great! Always pegs 5 bar at 2000rpm plus and never below 2.5 bar at idle, even in Texas heat.

928ntslow

Not sure about the motor oil, but I switched to RP gear oil and wish I hadn't. It made shifting my 5 speed clunky and difficult. I wish I had stayed with Redline. Thus far for me, RP hasn't impressed me.

hacker-pschorr

Started running it in my track car in 2005. Nothing to complain about. It's in my street (supercharged) 81 right now and my Ford 5.0 powered replica Cobra.

For the street cars I'm only running it because I picked up a few cases on sale at NAPA for less than Mobil 1. With the regular price for RP, I don't see any benefit over Mobil 1 on a street car.
FWIW I changed out whatever the 5 year old gear oil in my 79 with RP, everything got better (shifting wise). Anything would have been better than the old crap that was in there.

People I know who race C5 ZO6's swear by the stuff.

hans14914

I run Royal Purple products in my 89 s4. When i made the switch over from conventional oil to RP in the 89, i noticed an immediate difference. Lots of small "unquantifiable" things like new engine note, slightly better initial launch... etc, but the telling difference was gas mileage. I did the change right before the trip to SITM, and was able to make it from Indianapolis to North Carolina (not quite banner elk.. maybe 20 miles short) on a single tank of gas. Probably could have made it to that exon station as you come into town, but didnt want to risk sucking up any tank sludge.

Needless to say, i have been very happy with it, but i also swapped out all fluids (trans/diff) which i am sure helped with the mileage, not just the motor oil alone.
Hans

bronto

Keith, so far you're the only "nay" vote. Do you have a LSD? If so are you using the modifier?

bronto

Hmm, this from RP's web site:

"All viscosities of Max-Gear are formulated with hypoid friction modifiers necessary for use in clutch or cone type differentials. No additional additives are necessary."

So I guess no modifier is needed for LSD? If so I'd still like to know from Keith if he's got LSD. Could be what makes the different results make sense.

hacker-pschorr

bronto,
My 79 has LSD (no issues with RP). My friends who track ZO6's that run RP also have LSD, they do not use any modifiers.

Keith's car is an automatic.

bronto

Update on this.

I switched out to Royal Purple when I had my '79 serviced in December. Somethings are better, some are worse. Specifically, once it's up to operating temperature, it's a very nice experience. However, it's a lot worse when it's cold. Some gears grind terribly, and it's hard to get it into those gears. What's odd (to me) is that the "bad" gears are all on the "back" throw of the shifter; 1st, 3rd, and once even in 5th. Some mornings I just don't want to even try and get to work using only 2nd and 4th. I'm wondering if this isn't really some sort of adjustment issue? But OTOH, why would it not be an issue once it's warmed up? FWIW, it becomes somewhat useable after about 5 miles, much better after 15, disappears by 30.

hacker-pschorr

Hmm, sounds like my car when the clutch was starting to fail.