miata oil

[asoduk]

I have a 1991 Mazda Miata spec race car in addition to a 1996 summer DD miata.

With my other cars being Saabs, I keep a pretty decent stock of Mobil 1 0w40 and Rotella T6 5w40. I have used both in the miatas over the year with no problems. I have also used Supertech 5w30 synthetic and Mobil 1 5w30.

I was at Wal-Mart yesterday on an oil run in preparation for both cars coming out of storage in the coming weeks. I was planning on putting Pennzoil High Mileage in the street car, but they were all sold out. I ended up in the clearance isle and found 5qts of Valvoline 5w40 Euro in addition to a 5qt jug of Pennzoil Ultra 5w30 (the old kind).

My thought is to run the Pennzoil Ultra 5w30 in the race car from all of the great things I have read about it and just run it for the season. The engine has about 65k on it, with the last ~15k being all on track. The car only gets driven in/out of the garage/trailer and on track. Any reason not to?

On the street car, its has ~145k. I have had the car since about ~125k and have always used whatever synthetic I have laying around or is on sale. I'm thinking that since I will probably only drive it a couple thousand miles this year I may as well just put something cheap in it, but when shopping for oil I have a hard time not paying the extra couple bucks for synthetic. I'm thinking 0 or 5 w 30 or 40. The only reason I had though about Pennzoil High Mileage was to help out the seals.

I was going to save the Pennzoil 5w40 for one of the Saabs.

Just looking for some opinions.
Thanks!

 

[SilverC6]

Man, a Miata spec race car.

I've be shopping for one of those to share with my two sons.

Just got back from the 12 hours of Sebring race and we all have the racing bug.

The PU is great oil but I would worry some about shear to a 20 weight in a racing application.

 

[olddognewtrks]

Here's an article I saved, from MX5miata.net, from member AussieMX5, posted October 2006. Enjoy.



A little something to set the cat amongst the pigeons

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There has been a few posts regarding oils/fluid lately and Mazda's recommedations so I have decided to share some info past on to me by one of Mazda Japans more senior engineers.

I had the luck of meeting him a couple of years back while he was in Aus. He heads here a couple times a year to help in the process of changing model ranges to meet Australian standards and enviromental considerations (fuel quality, roads, weather etc). We met because of a demonically possesed (well thats all I can attribute it to) RX8 that just had so many engine, electronic, gearbox and even interior fit and finish issues Mazda Aus was throwing their collective arms in the air. While he was in the country they bought him in to take a look at the car. It was from his input that I was fully refunded the cost of my RX8 and offered the MX5 at cost.

To his credit he did the very Japanese thing and felt it was important that he meet and apologise to me on behalf of Mazda Japan. He really did seem embarressed by the cars failures.

It was from here that we struck up a friendship. Had a few dinners, even took him out on one of my track days where he spent a fair portion of the day in my mx5 driving around one of our more famous circuits with a couple of our top racing drivers beside him improving his skills!

During this time the question of oils came up. I asked what would be best to look after my NC considering the use it gets. His response was the Mazda specifications are a compromise between protection and economics and through the use of better oils and revised changing intervals you can give the car far better protection. If Mazda increased their recommendations for oils and servicing to meet the ultimate level of protection then they would lose sales due to the servicing costs. In a nutshell Mazda's recommendations offers the best protection for a certain budget level.

Together we came up with a plan for my NC based on my useage and his knowledge/experience.

Engine oil: I now run Castrol Edge fully synthetic 10w-60 (was Castrol R until they changed the name). This oil is thin enough for cold start in aus climate but offers increased protection for constant high rev use and high heat applications. His words were a great oil for any NC that see's track days. Looking at the oil after seeing similiar track time to my previous dealer installed synthetic 10w30 and it looked a heck of a lot better after being drained out compared to what was left of the 10w30.

Gearbox: this is the one that will get some negative feedback by forum members but again is on his recommendation - Redline lightweight shockproof. I was unsure of this as I have read the posts about it and also read the Redline material that does not recommend it for Syncro type transmissions. The real problem he explained is in transmissions that use small underpowered pumps to circulate the oil around the gearbox and that because of the way this oil is attracted to metal it will sometimes block these low powered pumps (The Subaru STI is a classic example of this he stated). As Redline cannot test in all non race Syncro type gearboxes the earlier statement is easiest. Also because of its thin nature should be changed more frequently to keep maximum protection and avoid deterioration. I have to say after putting it in my gearbox the difference in feel is stunning. The gearchange is like a hot knife through butter and no issues with 2nd and 3rd I had been having (The occasional difficulty of getting it to go into gear & grinding when this happened) The car also feels smoother and seems to rev out a little easier above 5000rpm. The driveline clatter has also been reduced at low rpm or in neutral.Although he did suggest you drive it a little gently for the first couple hundred km's just to let it fully settle in.

Diff: Again the Redline Lightweight Shockproof. Things seem smoother again and it does feel as though I do get better drive out of tight corners although that is something very hard to measure.

Change intervals: He recommended I change the engine oil and filter every 5000km because of the track work. If I was not doing track time he recommends oil change every 10,000km and a filter change every 5000km. For maximum protection I was told more frequent filter changes were better that changing a good synthetic oil all the time as a good synthetic will handle the 10,000 interval. For the gearbox and diff I change every 20,000km again because of the track work and also this keeps the lightweigh shockproof in the sweetspot for maximum protection!

Well thats it. On this regime I have to say my NC runs truly brilliant and it performs smoothly enough that the Mazda mechanic who performs the services has commented on that. At the last dyno day with 3 other NC's all on the same dyno within the space of 45 minutes before lunch (mine last) my NC scored 94.6kw at the wheels while the other 3 were 90-92 at the wheels with the only difference being beside my oils and track days, I am on JIC's they are on the Eibach springs and all on the same tyres. Judging by the figures and feel my NC seems pretty happy!

I should not say anything but just for a little tease last month while he was out here working with a team from Mazda and a very well known organisation I cannot divulge, he invited me to have a small test drive out at Broadford Motorcycle complex of an NC MX5 they are building to compete in Tarmac rallies around Australia. I promised not to say too much but from what I experienced Mazda will not be putting the MPS3/6 2.3l in the NC any time soon. Scary fast and without massive electronic nannies built in or serious de-tuning I think a lot of people would kill themselves in it on the roads! That's about as much as I can say on that

Cheers

 

[asoduk]

My car is an "na" as opposed to the "nc" in that article. I have the 1.6l DOHC engine. I know that I am running against other miatas using oils from a 0w20 to a 20w50.

I guess now my debate is simply between Rotella T6 5w40 and Pennzoil Ultra 5w30. I think either will be fine choices. What to do?

 

[A_Harman]

How hot does your oil get during an aggressive track session?

 

[IndyIan]

What's the oil pressure at the end of a race? You can use the difference betweeen that and the pressure in street use to help decide if a 40W is needed.

 

[quarterliter]

10w60? I would almost think a motorcycle 10w40 would be a better bet. Do you have an oil pressure gauge?