ive always changed the oil in my parents cars with traditional real oil, but i changing mine now that im about to put my miata on the road. can you guys enlighten me on synthetic? Will i notice a difference? Wats the best brand as far as bang for the buck??
Wal-Mart Supertech.
Seriously. It's got what engines crave.
The biggest benefit of synthetic is that you can run it much longer between changes. You may see a slight increase in gas mileage. Cold weather starting is enhanced.
You may or not notice any difference as far as performance
.Personally I prefer Amsoil, it is argueably the best but it is not cheap.
I change my oil once a year, around 9K miles. I do this on both of my vehicles,
Well due to a lawsuit by Castrol synthetic oil may not be synthetic.
It seems that Castrol sucessfully argued in court that if an oil performed to some set of standards they should be able to call it synthetic. In other words they argued that synthetic wasn't a material, but a standard.
Amsoil, Royal Purple, and Redline are synthetic. Each of the other brands offers products that could be dino oil, a blend of dino oil or a fully synthetic version. The question is, which is which. Marketing hype has blurred the line.
I run Amsoil and I don't worry about it.
carguy123 wrote: Well due to a lawsuit by Castrol synthetic oil may not be synthetic. It seems that Castrol sucessfully argued in court that if an oil performed to some set of standards they should be able to call it synthetic. In other words they argued that synthetic wasn't a material, but a standard. Amsoil, Royal Purple, and Redline are synthetic. Each of the other brands offers products that could be dino oil, a blend of dino oil & synthetic or a fully synthetic version. The question is, which is which. Marketing hype has blurred the line. I run Amsoil and I don't worry about it.
Yes in the USA "synthetic" is a marketing term whereas in the rest of the world sythetic uses group 4 base stock oils (PAO). In this country group 3 base stocks (highly processed mineral oil) can be used and labeled as "synthetic".
The only issue I've heard about synthetic oil in older car is you might start leaking a little more oil b/c they don't have an additive that swells up the gaskets, but I've never tried. I use a semi-synthetic in the benz.
I started using mobile 1 in my dad's focus and figure about 7500mile oil changes. In the benz I use a so-called semi-synthetic german oil, which costs 20$ for 5l. I use the lubromoly b/c the additive package contains MoS2 which is a good lubricant.
Read Bob is the Oil Guy online. More info then you can possibly absorb.
Basically what has been put forth so far is correct, the only real synthetics in this country are the Big 3 (RP, Redline, Amsoil). All are very, very good. I personally like Royal Purple. I run their street oil in both the the P71 (5W20) and her Grand Prix (10W30) as well as John's LS2 GTO (5W30). During winter/non-racing I change the oil and filter (filter is the most important, grab a Wix/NAPA Gold/K&N) every 5,000 miles. When it's racing season we shorten up the GTO to 2,500 (and the P71, but I'm not racing it this season).
The biggy with synthetics is to swap everything. On all 3 cars (plus everything but engine oil in the RX-7) all of the fluids have been flushed/changed out for Royal Purple synthetics. Gear oil in the rear axles, oil in the engines, ATF/Synchromax/gear oil in the trans/gearbox, PurpleICE in the coolant, plus ATE DOT4 in the brakes/clutch systems. The overall effect of a total swap is a definite increase in efficiency. We saw a solid 3 tenths in the 1/4 mile on the GTO plus a 1-2MPG gain. The P71 saw an even better improvement on mileage though some of that could be attributed to just being fresh fluid. The shifting action in the RX-7's trans is MUCH improved and smoother with less grinding of the 2nd synchro.
Do not under any circumstances run synthetic in an older/high mileage rotary. It will swell the side seals and seize it. It's A-OK for a fresh rebuild. Do to this I am forced to run regular ol dino oil (10W30 Valvoline) in my 7 and I change it every 1,000 miles (because it's raced so much). 233,000 miles without a rebuild...
P71 wrote: Do not under any circumstances run synthetic in an older/high mileage rotary. It will swell the side seals and seize it. It's A-OK for a fresh rebuild. Do to this I am forced to run regular ol dino oil (10W30 Valvoline) in my 7 and I change it every 1,000 miles (because it's raced so much). 233,000 miles without a rebuild...
Sorry to threadjack, but this is relevant to my interests. So, since my FC's 13B was rebuilt 10K miles ago by a Mazda dealership, then running Amsoil or RP in it should be OK, right? Will it decrease engine life, and if so, by how much?
I dunno what the threshold is (except that 26 years and 233,000 miles are too much...) but I would imagine a fresh rebuild would be pretty safe. Ask around on www.rotarycarclub.com .
The big deal is swelling seals, and your seals are still "new". The only problem is because oil is injected into rotaries it's kind of expensive to maintain RP/Amsoil/Redline in one all of the time...
RexSeven wrote:
Sorry to threadjack, but this is relevant to my interests. So, since my FC's 13B was rebuilt 10K miles ago by a Mazda dealership, then running Amsoil or RP in it should be OK, right? Will it decrease engine life, and if so, by how much?
Mazda recommends using a quality conventional oil (Castrol GTX for example), because they have had problems with cheap synthetics not burning cleanly and leaving carbon buildups. It's easier for them to say don't use synthetics at all than to say you should only use so and so. Most of the rotary experts recommend a high quality synthetic.
I ran Amsoil on my 12a for years, it had 124K on it when I started using Synthetic, it never ran better, I also used their two stroke oil in the fuel and removed the OMP.
Cool, thanks.
BTW, YaNi, did you ever get that PM I sent you?
I have had great results with synthetics wear wise. My Escort went 280k before I totaled it and never burnt any oil, and currently my Malibu is at 212K and going strong. I put it in everything with a good filter and change it every 6 mos/10,000 miles.
well my NA has 111k on it, should i make the switch?
I would say yes if you do what aussie did and disconnect the OMP and run 2-stroke oil in the gas. I will do the same if/when I ever rebuild mine.
longhorndude wrote: well my NA has 111k on it, should i make the switch?
your NA is barely broken in. 
go for it. i'm considering switching to a good synthetic in mine, but then again, it's about to cross 240,000 and doesn't use a drop...so why mess with success?
I once had a track rat Miata that had been fed nothing but Royal Purple for >100k by the previous owner. I was adding a quart every 500-1000 miles until I switched to plain vanilla Penzoil high mileage formula (in the copper-colored bottle), after which it used not a drop. 
YMMV. 
I use Wal*Mart Supertech full synthetic in the 20v Rolla, Camry, Truck, and Lexus V8. They get changed at 5K intervals, or more often maybe for the Truck. The Esprit gets Mobil 1 15W50 silvercap, as recommended by Lotus. Right now I have Mobil 1 20W50 "V-Twin" oil in my bike, but I think it makes more valve noise with that and I'm going to go back to Genuine H.D. dino oil at the next change. The Sportster has Genuine H.D. 20W50 in it.
Whenever I have switched from dino oil to full synthetic, I have noticed about a 3% improvement in mileage.
Besides Bob the Oil Guy, there is a thread(really long) on the Porsche board at Pelican, by the resident oil engineer. The condensed version is Brad Penn is the best, followed closely by Amsoil, Mobil V-Twin, Royal Purple, and Redline- due to the anti-sludging properties in each of these oils. Being air cooled and using twelve quarts per oil change, cost per quart pales in comparison to cost to fix with my 911. As important is the filter, but that's another long winded thread.
OK, here's a question for the resident oil experts. My 1993 Accord is about to come off the road for the next seven months or so, since it is my winter car. It's currently almost at the end of its oil change interval, and is currently using Mobil 1. I will have to move it around from time to time over the summer, so I can't leave it empty. So, should I leave this oil in and replace it just before it goes back on the road in the late fall, or should I replace it now and leave it mostly sitting around for the next seven months with a crankcase full of fresh oil?
I always store a car with fresh oil.
For miatas: the the HLAs start to tap around 3,000 miles regardless of synthetic or dino oil, so you won't be able to get longer intervals. On m.net some people say not to change to synthetic after ~100k (the logic being if it's running well and happy, why upset the balance), but it's subjective.
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