Hello guys, I have a question about the oil for my 8.
I asked couple of dealers which oil is better Mazda or Castrol?
Omest of them say what they use is better. One says they use Castrol oil and Castrol oil is better than Mazda oil and one says they use Mazda iol and Mazda oil is better than Castrol. Well I trust you guys more than dealers so what do you guys think? Which on should I go with?
Thank you.
Leo

 

My mazda dealer only uses Castrol (NO SYNTHETIC!) so that's what I've been using to keep mine leveled off. She purrs like a kitten. :D

 

Note: Mazda uses Idemitsu as the factory fill oil. This product was not easily attainable in the US until recently.

Different dealers use different oils I have found, however what is usually stocked on the shelf is typical dino-oil for the entire lineup. However now Idemitsu oils are starting to show up here and there at some of the better dealers. This might be something to think about.

 

I'm new to the forum. I just recently got an RX-8, velocity red.
Anyway, so, are ya'll saying NOT to synthetic oil? I haven't changed the oil yet, but going to soon, about to hit 2500 miles.

Thanks,
Yoda

 

That is correct..... DO NOT use synthetic oil. It's in your owner's manual.

 

It is a matter that is debated. Your oil needs to burn a little. Some are worried that synthetic won't burn as easy.

 

For dino oil I recommend either Havoline or Castrol. They are both very similar to each other. The reason I like them is because while certain additives are good for oil, too many of them isn't. These two oils lack a certain additive that causes more carbon buildup.

For synthetic I like Amsoil or Royal Purple. I have used both and am currently running Royal Purple. It's great stuff and WILL NOT HARM A ROTARY!!! I don't feel that any synthetic will harm a rotary new or old but these most certainly will not.

 

Not to continue the synthetic .vs. dino oil thread, but here is what I know about that and Mazda oil .vs. Castrol.

1. I was told that Mazda oil, is manufactured for Mazda by Castrol. Same stuff in both cans.. er bottles... plastic jugs. Different name outside.

2. The issue with synthetic has to do with the Renesis engine and the cat combination used in the US. The synthetic does not burn as completely as dino oil and can clog the cat before it reaches 100,000 miles. This is the reason Mazda does not recommend synthetic in the US and does recommend it in other countries.

This bring me to another quandry about oil containers. At one time oil came in glass bottles, then it came in tin cans, then in paper cans with foil lining on the inside and now in plastic bottles. SO is the plastic bottle the final container and is it the best because it is made from the substance it contains in another form?

 

Not all synthetic oils are created equal. Perhaps this is just a blanket statement from Mazda to just cover all the bases in the easiest way. I know for a fact that Royal Purple and Amsoil will both burn very clean. They are also both superior to the standard synthetic oils you get over the counter at the auto parts store.

 

David Canitz (an employee of Royal Purple) and local RX-club member uses the synthetic oils in his GT3 (rotary) race cars and on his street drive FD. Maybe I can have Dave come out and display some of the product and answer some of the questions sometime soon.

(Maybe next meeting?>)

 

Ive never seen mazda oil. Only trans fluid. We use 5-20 bulk motorcraft.

 

That is probably the case. Mazda just may not want to go to the trouble to test all the different synthetics and makes the blanket statement to cover their hind quarter with the EPA and other powers that be.

 

That would be interesting and I would do my best to make such a meeting, but I notice from what you stated that he is not running a Renesis with stock cat which is the combo that Mazda recommends against using synthetics in because the cat has to last 100K miles.

If Royal Purple would cover the same parts as my emissions warranty, I would jump on the synthetic band wagon in a heart beat. I have used synthetics in my piston engine cars and trucks for years and never had an oil related failure in any of them.

When I had my RX-4, I had 1 oil related failure and one repair assembly failure that caused an apex seal to get blown out. Back then synthetics were not out in the marketplace like they are now.

 

Mazda has been kind of like John Kerry. They tell you one thing before they tell you the opposite. They have stated in writing in the past that synthetics are only applicable for the Renesis rotary and are not compatable with all pre-Renesis rotaries. Their explanation was that synthetics may break down the o-rings in the older rotaries but newer materials have solved this issue in the Renesis. Of course it is all just a bunch of crap and it works fine in the older engines. This again probably goes back to the fact that if you use certain synthetics in certain old old rotaries, say from the '60's and '70's, you might in fact encounter a problem. It still sounds blanket statement to me but this is easier than listing all of the exceptions.

I have also seen elsewhere that the cat was mentioned in relation to synthetics. That is a bunch of crap. If a cat can stand up to near 2000 degree exhaust temperatures, how is a small amount of oil in it going to hurt it any? It won't but more importantly synthetics burn MORE thoroughly than conventional oils. There should be less of an issue with the cat.

 

So if I use Royal Purple will I have purple smoot on my exhaust tips rather than the current black smoot? That could give it a cool factor.

I really didn't want to get back into rehashing the synthetic .vs. dino thing again since there seems to be so many different issues and criteria involved. Sorta like, 2 car garage .vs. 3 car garage and if it is detatched will the cost to run my AC go up. The issue being that at some point someone will say that they don't care about the cost, they want one or the other.

 

i just wanna put my 2 cents in.... when my father used synthetic on his 85 GSL after watching a commercial of a black FD in a pennzoil synthetic he said he would try it to see a difference, well a big difference indeed, the synthetic oil is too slick for the oil seals to seal properly and it started leaking huge amounts of oil causing a plume of smoke as if someone took a supra with slicks and did a 2 minute burnout...not good...my advice use either Havoline or Castrol 20w50 i use it in my 85 GSL-SE and when i change the oil it seems that the engine keeps getting cleaner; oil is almost new...but then it also has to do with the way the generations of 13Bs were built...no matter...

 

Funny you should mention that because I used to use 20W50 Castrol in my RX-4, of course the RX-8 specs 5W20.

I also noticed that you are in Killeen. The Saturday after I bought my 8, my son and I drove from Houston to Killeen because I used to live there back in 63 on South 10th Street just past Nolan Creek. From there we drove to Copras(sp) Cove and then to Austin and back down 290 to Houston. The whole trip put 700 miles on the car in about 9 hours. Hey, we had to stop to eat twice and that whinding road down to Austin sure is smooth at speed.

 

RX4 you aint lyin when it comes to that road to austin, thats where i topped out my 85 GSL-SE at 135 before i had to get on the brakes cause my radar was going off!!! 130 is fast on an old school car but going that spped in a 8 feels like 70!! by the way what color is your 8?

 

Humm, that info used to be in my tag line. In any case it is a Titanium Gray GT with black leather. Only mod is the RX-8 third stoplight mod.

That road was actually Highway 183 from Lampassas to Austin. I actually stretched it out to 145 a couple times before I started getting occasional beeps on my radar detector right before I got to Seward Junction and slowed down. Then as I was approaching the 259 intersection I saw two local cops turn South on 183 and take off as if they were chasing someone. So with that good a front door, I sped up and paced them at up to 100 until they slowed down and turned off at Cedar Park. I decided to play nice and stop for gas and a coke before going on to Austin. I stayed at the speed limit or close to it until I got back to Houston, but never saw another cop the whole way.

You are absolutely right about the 8's feel at speed, especially on that smooth fresh asphalt.

I used to have a new 78 Plymouth Fury sedan with the A36 intercepter package and at apeed it was a beast, a scary beast. Had it up to 165 once and it felt like I had to fight the wheel above 120. The 8 is so smooth at those speeds (120+ Stilll haven't tried to go faster than Mazda says it will go) that the only thing that feels different than 70 is the envelope of air that you start to hear going by. If you have been there, you know what I mean.

 

i hear that...have you been to K-townlately? beause the are 2 TiGray 8's here but only one i see on a daily basis as i leave from school. when i get to the stop light at the corner or blockbuster(jasper and i think old fort hood road) i see a Tigray8 that looks to be coming from 183. the other i've seen is a bit more rare to see cause i talked to the owner in a parking lot after i saw a nitrous bottle in the back and he told me that after he was going to save about 5k of cash he was going to have the motor recieve a D bridge-port, now correct me if im wrong but since all of the 8's operations are done by the ECU would't there be at least some falseness on the guys part because i know for a fact that Racing Beat is still trying to braek the code for the ECU and bridge-porting the renesis would not do barely any good until they figure out the ECU in order to tune the car for the bridge-port. seriously the 8 would barely benefit because of its NA limitations on fuel delivery. but if it was a turbo then we would be getting somewhere. but until i see that RB breaks the code i will always know in the back of my head that when that guy is talking about motor work for the 8 he is just BSing.

every now and then a friend of mine will let me take his 3rd gen out for a spin with hime riding shotgun and my favorite place to go is to take that exit just before florence and top it out at 150. its a pretty long road of i think at least 10 miles or more cause i never went as far as that exit up until Harold's junk yard. but i'll tell ya, there are enough fast corner there to feel the 7s suspension and rubber being glued to the asphalt. talk to you later.

 

No, I haven't been to K town since Feb.

As far as a d-bridge port and Nitrous goes on the 8's new porting, you will have to ask someone with a lot more RE building experience than me. On the ECM, well there are others working on that besides RB, but I haven't heard anything definitive.

Personally, I believe that there would be more gained in actually hacking the ECM than by changing the Renesis porting scheme and if I were going to look at NOX I would not use a dry system and I would want to insure that the third intake ports were open when it started sucking on the bottle. Maybe trigger the NOX with an isolated relay triggered off the 3rd port solinoid feed. I might even experiment with the secondary intake ports but I would also want to measure the EGT to insure that I didn't melt the cat. Of course being the pesimist I would also want another engine standing by.

Edit: In other words, I won't be the guinnepig on this one. I will drive my stock 8 to it's limits from time to time and enjoy the car it is. If Mazda comes out with something better later, I park this one and buy the new one.

But this has nothing to do with Castrol or Mazda branded oil, So I will bow out of the discussion in this thread. It might be better in one of the technical areas or the regional area.

 

The biggest gains are going to come from the exhaust ports on the Renesis. We can already retune the ecu. The Ric Shaw ecu is by far the best one out there at this time and can control everything we need it to. You can bridgeport the Renesis. The problem with this is that you would need to modify the rotors to accept the older style deeper 2 mm apex seals. You'd also have to use the older corner seals, preferably the aftermarket solid ones. Without going into detail as to why you'll just have to trust me. It is much more involved than just opening the engine, bridgeporting it, and reassembling it. I don't know what the advantage of a D port is on a rotary. Without D shaped intake runners, you aren't gaining anything. The only rotary D shaped ports are those that were only available on the factory prepared 12A and 13B peripheral port race housings. Some aftermarket tuners may use a D shaped port but they also need to fabricate a new intake manifold to accomodate it. It sounds like alot of what you were told is bs. It's not impossible. It just isn't easy.

 

to tell you the truth Mazda uses both Castrol and Idemitsu oil for its cars. but they use castrol for thier grocery getters and use idemitsu for thier top of the line models like the RX-8, MS protege, MS miata, and V6 Mazda 6s. i asked my local dealer Dennis Eakin Mazda's mechanics and the told me thats what they use. apparently Idemitsu is a High-performance racing oil that is similar to RED LINE oils but Idemitsu is just now recently becmoing popular among import racers seeing as its about 30-50 cents cheaper than Red Line.