ok these are really 2 quick questions and i don't know the answers they are fairly simple and not that pressing but the one about oil is, you guys told me to by 5w20 and I accidentally bought 5W-30, is that going to be a problem if i put it into the car??? I was told it wouldn't do anything tooooo bad, but i just want to double check.

The other is, a lot of you guys talked about Premix, now i don't know what it is, but i bought this orange stuff called 104+ octane boost, and the guy at advanced auto parts said thats the only stuff that came close to what i was describing so i bought it and want to make sure this is the stuff you guys are talking about.

 

Nothing too bad going with 5w-30, especially if you're in a warmer climate.

Octane boost has nothing to do with [oil] pre-mix. Pre-mix provides enhanced lubrication to the rotor seals for better track performance.

Higher octane [gasoline] prevents pre-ignition (aka dieseling , knock, ping). You only need just high enough octane for smooth operation - any higher is a waste of money.

 

If you live in the New York area (I presume you're from there) the 5W - 30W will be fine....+1 on the pre-mix...

 

If you decide to pre-mix oil in your gas, and if your car is stock, you should use a two-stroke oil rated for dirtbikes or snowmobiles - the marine stuff (TCW-3) has metallic additives that could damage your catalytic convertor over time.


S

 

I've seen dirt bike oil kill cats too.

 

5w30 is what the RX-8 should be running. The only reason Mazda recommends 5w20 is to improve fuel efficiency.

Premix = 2stroke oil in your gas tank. I would only use Idemitsu fuel lube or Amsoil Saber Pro.

100:1 as maximum, 150:1 as normal and 200:1 as minimum.

12oz, 8oz and 6oz to achieve the ratios above per full tank of gas. That’s roughly 1$ per tank @ 8oz.

You should also think about getting a Sohn OMP adapter so that you can use a synthetic oil and feed your rotors fresh 2stroke oil that is meant to be burned.

 

Cat's are easy to replace.

I worry more about clogging the fuel filter!!!

 

Love how you make that sound like a "bad thing". Better fuel efficiency—oh my god, no!!!

 

So you care more about fuel economy than you do about the best protection for your engine?

It sounds to me like you bought the wrong car.

 

these ratios mentioned are only if you disconnected the existing OMP. if you run with the OMP at 100:1 for the premix in the fuel tank, you will have too much oil

 

It is irresponsible to make a blanket statement that 5W30 is "better" than 5W20.

I doubt anyone on this forum could give a definitive answer to that, even if they had the data.

To make a 5W20 oil, and have it meet the specs and stay 'in grade' over the whole oil change interval, is virtually impossible for a mineral oil - some or all of the basestock must be synthetic. These are new technology - ten years ago oils of this capability just did not exist.

A thinner oil will circulate faster, reach bearings sooner, have lower back pressure and filter d.p., cause less friction, less fuel use - and crucially - cool better.

Rotaries do not usually die from bearing failure - heat is the enemy, and a 5W20 will just do the job better.

S

 

too much of what oil ? premix ?

Im mixing about 120:1 right now. Engine has never been happier. I can feel it ... she talks to me every day

You can say anything over 100:1 is just a waste of money. but theres no such thing as *too much oil*.

 

but 5w20 does not lube parts as good as 5w30. In United states (or the NA market) we're having an unusual high*er* failure rate than the rest of the world. and we're the only part of the Whole Rx8 who recommends 5w20.

Just like GM's Dex-cool, it *suppose* to cool better and last longer, well, at least on paper. But the reality is, it suck at cooling, and it just wont last. and finally people sue GM.

It sounds like we're going thru the same path.

There are people who can live with 5w20, but people who use 5w30 from day 1 (well, starting from their 1st oil change), seems to have less problem. Thats what I've seen for the past 2+ years on this forum.

5w30 or 5w20 would be fine. but I like 5w30 more, if NYC isnt that *cold* I will use 5w40.

The Octane Boost 104+ thing is just a waste of money. if you can return it for a full refund please do so. Most people dont know wtf is premixing so asking the folks working @ Advanced Auto parts usually wont help. You can just go ahead and walk to their motorbike section (probably somewhere in the corner), and start looking at bottles with *2-Stroke oil*. There are a lot of them out there, all major brand has a 2-stroke oil.

 

Why do you assume one must choose between fuel economy and engine protection? Have you considered the possibility that, in fact, you can have both?

A popular rx8club.com "fact" is that use of 5W-20 led to engine problems. The peculiar logic goes like this:

1. Mazda specifies 5W-30 for all RX-8s around the world, except in North America.
2. Mazda specifies 5W-20 only in North America, because Ford/Mazda wanted to "up" EPA ratings as much as possible.
3. Only NA Renesis engines experienced compression loss.
4. Therefore, the use of 5W20 must be a factor leading to the engine problem.

Unfortunately, that's faulty logic. Circumstantial evidence that doesn't prove anything. Other variables peculiar to American RX-8 ownership (i.e. driving habits, ECU calibration, how often oil level is checked, local climate, engine modded or not, etc.) might also account for the problem.

Coming on the heels of the last RX-7 and its reliability issues, I find it hard to believe that Ford and Mazda would introduce their new rotary-powered car with a grade of engine oil that would not fully protect the engine. Don't you think Mazda and Ford engineers would fully test the Renesis on 5W-20 before using and recommending it? That's got to be standard procedure with any change to a new oil - particularly on a new model whose reliability would be under the microscope.

Yes, it's possible that use of 5W-20 was a factor. But oil technology continues to march onward, and it's also possible the 5W-20 can both a) improve fuel economy and b) fully protect the engine.

 

I use 5W-20 becuase I figure the automotive engineers who designed the engine/vehicle know what they're doing and have a sound reason for recommending it.

But again in response to the original question, 5W-30 won't hurt anything.

 

120:1? thats about half a liter of 2 stroke for a tank of gas. Then with the OMP working, you also have some engine oil too. the ratio will be close to 100:1 or even 90:1 of total oil vs total fuel burnt.

 

more like a bit more than 1/4 of the liter.

Sometimes I go crazy on it, sometimes I just ignore it. its about 4-12 oz, usually about 8. It depends on my mood and how much gas I have left in the tank.

 

I just got my 04 GT last week and wondering exactly what needs to be done for "PREMIX". nothing on here says exactly what steps that needs to be done to do this for the first time.
How do I decide what oil to use in the car in general?

I was told no synthetic and to use 10W30 due to St. louis's heat is that right?

what is the OMP? and how do I disconnect so I dont have to much oil as one post said?

what is the exact measurement anyone here recomends?
any other helpfull hints would help me out alot.

Thanks

 

Yes, 10w30 will hold up a bit better in hotter climates than 5w20.

Nothing special to do, or to disconnect, for pre-mix. 4 oz of pre-mix (2 cycle oil) per tank of gas for general use. Easiest to add prior to fill up for best mixing. Idemitsu preferred by many.

http://www.idemitsu-usa.com/page_210.htm

 

So for a new RX-8 owner in St. Louis...using 10w30 and adding the 2 cycle oil are two good recommendations? Any other tips?

Thanks in advance!...

 

here is a premix question I've been meaning to ask:

do you dump the premix directly into the tank or are you using a clean gasoline container first?

 

I use a 4 oz bottle that I got from the container store for like 2 bux.

Pour the premix into the bottle, dump the whole thing in to the tank, fill her up, close the cap, drive away knowing that its lubing the seals.

 

thanks, no one ever mentions that in all of the hundreds discussions on this subject!

 

nope.

if you read you will find 5 oz dixie cup..


beers

 

What is the advantage of premixing anyway??