Cody Helton

Almost everybody on this forum can agree that premixing does help lubricate the inside of you engine. I want to premix my 2004 six port, but I have heard myths about the premix clogging the fuel pump. I definitely value engine reliability over my pump, but I don't want to be replacing pumps every 3 months. So my question is, is the whole fuel pump clogging thing just snake oil? And if its a real issue, what would be my alternative to get more oil into my engine? (or any longevity mod for that matter) Hopefully done for less than $200.

9krpmrx8

iTrader: (46)

Premix clogging fuel pumps is not an issue. I have never heard of that happening.

Steve Dallas

There is some indirect evidence that Lucas Top Cylinder Lube monkeys with the fuel pump, but nothing concrete. Don't use that junk, and you'll be fine. I have premixed with Lucas Semi-Synthetic 2 Cycle Oil for 40K miles now with never a hiccup.

9krpmrx8

iTrader: (46)

I used Lucas (UCL) for a long time, and my fuel pump sock was nasty when I pulled it. But that pump lasted 100,000 miles and still worked perfecty well pulled to install the BHR assembly.

Steve Dallas

I think he's referring to this:

If he is, that is good news. It means he actually read the thread. :p

roto-moto

yeah I premix with Amsoil Sabre Pro Full synthetic 2 stroke and have zero problems from my engine. never seen or heard any evidence of it causing problems. never really heard of anyone getting premix issues unless they're using some crazy oil. Just stick to a good 2 stroke synthetic and you'll be good to go.

dannobre

iTrader: (3)

The biggest problem with the fuel pump sock clogging is with dirty fuel

A of stations in areas with high dust or water or just plain crappy delivery for the fuel will have more crap in the fuel. Also a lot of stations cheap out on the filter changes in the pumps

Premix with dirt = black **** on your filter sock

Premix with clean gas is no issue

No Premix with dirt = crap in your filter sock...

So really very little difference

I have taken a few 100K pumps out and they were spotless...and I have seen a few that were clogged up like 9K's photo in 20K or less

9krpmrx8

iTrader: (46)

The last time I pulled mine (year or two ago) it was spotless after 6+ years. But I have only used the Mystic JT-4 Synthetic.

Cody Helton

Yes Steve, that's the thread I was referencing. So the general assumption is that almost any synthetic/semi synthetic 2 stroke oil will work fine with no fuel pump issues? And as far as how much to put in, whats a good number to go with per gallon? (i'm breaking in my engine right now but im about 75 miles in, I might wait to start premixing after break in. thoughts?)

Cody Helton

From what ive heard, 4-8 oz per tank is a good start. (sorry for the double post)

Steve Dallas

1/2 Oz per gallon is the norm.

gwilliams6

I use the Lucas semi-synthetic 2-stroke and it works fine. I have tried many different recommended rotary premixes over the years, and now the Lucas for the past few years. It fits the bill and is reasonably priced and readily available.

wannawankel

I run 0.25 oz. to 0.50 oz. per gallon in me S2. Just switched from Lucas semisyn 2-stroke to Mystik JT4 (Sean and Snow aka JASO FD rated). No difference noted.

B*stards at Amazon just increased the price by ~ $5/gallon on Lucas and I got a sweet deal at Menards on Mystik.

wannawankel

UCL is a medium weight paraffin, it would "bond" (hydrophobic attraction to the sock) like hair conditioner does to hair. It builds up over time b/c it is less soluble in gas and more soluble to adhere to the sock.

UCL is primarily Distillates (petroleum), hydrotreated heavy paraffinic 60 - 100% CAS# 64742-54-7. The molecule is about carbon chain length of C20 to C50 or 2-5x longer than gasoline - hence the reason it likes metal and plastic surfaces.

UnknownJinX

So am I the only person that uses Idemitsu Premix around here?

I've run through ~3.5 bottles, and it seems to be pretty good stuff, you just gotta pay for it, and wait for it if you don't have a vendor around you.

In reality, any 2-stroke oil should do the trick. I just prefer something made specifically for the rotary.

NotAPreppie

I am but once this case is done I'm probably going to switch to Lucas semi-synthetic since I can get it Amazon Prime. Price after shipping works out the same but I get 5% cash back on Amazon.

Steve Dallas

Fixed.

UnknownJinX

Yeah, you are probably right. There is little hard evidence to show that it's really better than a good 2-stroke oil.

I have a case of a dozen sitting around now, so I think I won't be worrying about getting more anytime soon.

ogwazza

I used to race 2 stroke motocross for years so I use any 2 stroke oil I can find (including lawnmower stuff) :-)

MoMacAttack

Is Premixing going to interfere with the S2 oil delivery or aid in lubricating the engine more? Also, won't premixing damage the CAT? Or does everybody run a catless mid-pipe?

I'm looking to purchase a 2010 base RX8 and I want to treat it right!

ogwazza

You're right that it is extra delivery of oil (providing aid) to the engine. Some people block their oil squirters completely and go premix only.

I know when I tested my FD for emissions running pre-mix, it read very badly ...and I'd guess that it would block it up... but do you want to treat the planet and your CAT right or the engine?

Loki

iTrader: (1)

Premix doesn't affect the cat and it doesn't interfere with the oil injection.

MoMacAttack

I thought that any oil during the combustion stage might inhibit the burn or even get dumbed out into the exhaust altogether. This is of course due to the demands of the rotary place on the ignition. I'm all for premix. My question is, is there any detriment to running premix in an S2 that already injects more oil? Different ratio maybe?

Loki

iTrader: (1)

Most premix goes out the tailpipe anyway. Some fraction of what you put in condenses out on the walls of rotor housing. At the ratios we're talking about, it doesn't affect the burn rate.

The OMP is a more efficient way to deliver oil directly to the seal, but the downside is it only delivers to the apex seals. Premix delivers everywhere. So OMP+some small but consistent premix rate should give you best of both worlds.

NotAPreppie

TLDR:
Adding clean-burning 2-stoke oil as a premix will not significantly shorten the life of a cat if everything else is working fine. The catch here is making sure that what you inject into the combustion chamber (fuel, oil, pureed ostriches, whatever), is cat friendly. Avoid anything with zinc, sulfur, phosphorus, lead. "Ashless" is a clue because ash is the non-burnable leftovers from combustion, i.e. metals.



Any oil injected into the combustion chamber, whether with the fuel or via the OMP will get burned and sent through the catalyst and out the tail pipe. It doesn't burn as fast or energetically as gasoline but it does burn.

Burning oil (2-stroke or crank case) will use some of the oxygen because that's what hydrocarbons do. The ideal scenario with perfect stoichiometric burn will yield only CO2, H2O and heat. Additives and reality ruin this and we get NOx, soot, sulfur, metals and other crap. Running too lean or too rich can physically damage the cat but adding extra oil won't affect that (mostly because the O2 sensor will see that burning oil has used up a bit of extra oxygen and the PCM will compensate).

What WILL cause problems with the quickness are certain metals. They "poison" the catalyst material and block binding sites where exhaust products would normally interact with the catalyst. Some poisons or inhibitors like carbon and sulfur can sometimes be removed by an "Italian tune-up".

Metal poisons (lead, zinc, calcium, magnesium, etc) don't burn as easily as carbon and sulfur and when they do, they don't often form gaseous products so they sit around as ash. Some metal poisons actually incorporate themselves into the metal structure of the catalyst and deactivate it. This is why ZDDP as a lubricant additive has been on a slow phase-out since 2006; it's a triple-threat with zinc, sulfur and phosphorus and why using diesel oils in a rotary without an OMP is a bad plan if you have a cat.

Incidentally, carbon and ash are related but not synonymous. Carbon is just that. Get it hot enough with enough oxygen around and it will burn off. Ash, on the other hand, may contain carbon but will also have material that won't burn at temperatures seen in combustion chambers. Carbon forms during rich conditions when there isn't enough oxygen to completely turn all of the fuel hydrocarbons into CO2 and H2O. Ash forms when there are non-combustible components in the fuel (usually metals and semi-metals).