alright im getting ready to have to run premix in my car and im hearing all these different #'s on the mixing. what is it 1oz per gallon or 5oz's per tank??? also what kind of premix should i run any brand or a specific kind? i have just a 255 in tank walbro with the stock screen on the pump and the stock filter on the car should i change any of that???

Thanks

Brian

 

I think you'll be safe if you stick with the 1oz per 1 gallon figure. The reason I'm not mixing it as rich, is because I'm using amsoil 100:1 type premix that is made to lubricate well at a leaner mixture than normal.

Most 2 stroke oils are designed to be run at a 40:1 mixture (40 parts fuel to 1 part oil). Obviously 100:1 is a lot less oil, but I don't mix it that lean really. I've considered switching to the dominator line witch is designed for 50:1 mixture, but have stuck with the 100:1 premix because that's what the tech from amsoil recommended. And it's designed 100% to be premix, so that leads me to believe it might stay suspended i nthe fuel for a longer amount of time.

All that have been mentioned here are quality oils, amsoil, royal purple, red line, motoul ect. And will lubricate much better than a metering pump and motor oil, even at a leaner mixture.

 

ok well that leads me to believe it's more so that paper filters don't react well with 2 stroke, than the smaller micron filters being a restriction. I'm probably going to see about stepping down to a smaller micron stainless post filter.

I just want to clarify that I haven't had any issues with the stainless elements that I've used. I've had issues with a paper post filter, and a paper/mesh type tank pickup.

 

It is possible have full fuel pressure but be down on flow e.g pump can't supply enough fuel to the engine at full pressure, therefore a lean out occurs. You really need to know how much the pump flows at pressure. Some manufacturers advertise free flow gph only.

As far as premix ratios go I mix at 400:1 using mineral outboard engine oil (low ash). My current engine sees 9,500rpm regularly and has done 21,000km in 10 months. Remember that 2 stroke oil is designed for 2 stroke engines which have high load bearings that need lubricating. Rotaries need just enough oil to keep the seals lubricated and its not as much as people think.

 

I agree that rotaries dont need as much premix as people think. I dont even get CLOSE to the 1:1 ratio thing, its way too much in my opinion. Why would i say that? Think about your stock oiling system. Maybe use a quart of oil in 2000 miles? And how many gallons to go that 2000 miles? Assuming 20mpg, thats 100 gallons of gas. At a 1:1 ratio, thats 100oz of oil....while a quart of oil is 32oz. Anyone else ever notice that?

Just thought id throw that out there. Been using 3-4 oz of Redline Smokeless 2stroke oil per fillup for 4 years with no problems...

 

I've had bad experiences with the A1000 , it wasn't suited to my set up , it kept dropping pressure above 12psi , luckily I have a fuel pressure gauge and picked it up quickly , thats why I switched to a pair of Bosch pumps.

 

The reason for 1oz/1 gallon is because it's convenient to remember, and it approximates the rough amount of oil injection that Mazda went for *at full throttle*. When you premix you can't vary the ratio like Mazda does with the oil metering pump, so you shoot for the worst case scenario. When I'd premix I'd just dump in an 8oz bottle for 10-12 gallons of fuel. No problems that I could attribute to insufficient oiling.

I stand by my heckling, by the way. Fuel systems use paper filters too... mesh screens are not filters, they are just something to keep the major huge chunks out.

 

worst cas scenario...use a remote located diesel filter.It design is for high volume and high filtration with a heavy fuel.Maybe one reason they have so much surface area also ( and its a paper filter).

 

3 to 4 oz per tank...? wow thats not a lot of oil for 18 gallons of gas. I use 4 oz for 1 gallon in my 2 strokes 40:1.. 1 oz per gallon in my rotory just to be safe.

 

Just wanted to make a quick note on that comment. Two Walbros do infact outflow a Aeromotive A1000. At 14volts the dual Walbros will flow approx 130-140gph at 45psi and the A1000 only flows about 105gph at 45psi. When under boost at say 70psi of pump pressure the dual Walbros flow about 120gph and the A1000 only flows 75gph. Also keep in mind these are pressures at the pump not the fuel rail so they take into account for some lines losses. If you were running 45base and 20psi of boost that 70psi pump pressure is prob going to be fairly accuract with line losses figured in.

 

If that were the case Dude, diesel engines would be theoretical only(fuel filter in my EX is paper)

The dilution rate for pre-mix is such that the oil will not (forget the technical term for clumping) clump together but will remain in suspension with the gas.

My opinion, based on experience with small engines, is that you got a tank of crap gas and it varnished.

When I lived in small town TX (one gas station) this happened to me various times until I started draining the tank!!!!! after using the car.

 

i've been using a stock fuel filter, walbro 255 fuel pump, and autozone COASTAL tcw3 premix slightly less than 1oz per gallon (about 14-15oz per fillup) and i have had zero problems with this fuel system clogging you speak of.

 

you'll have to send me the info that your quoting for the walbro's because it sounds a little optimistic. And even if that info is accurate then I still don't trust the walbro considering the other car that had fuel starvation problems, had 3 walbro's die in the process. After a month of daily driving/autocrossing/night racing starving the a1000 for fuel, it never gave up, and after changing pickups, it's running like a champ. So I know the aero is in a whole other league than the walbro.

 

i speak of? WTF? neither the beginning fuel system, that I was having issues with, nor the modified that runs fine has a single part that is the same as what your running.

read! then type!

 

I've looked into the tank multiple times absolutley no corrosion, tank was drained between fuel systems.

Never said it was clumping.

and DUDE, do you under stand that all filters are not universal? That's why there are diesel fuel filters, and gasoline fuel filters. I bet if you tried to run diesel fuel through a gasoline filter it wouldn't flow near as much diesel as the engine would need.

i have no clue why i try to spread any kindof information to people on this forum. everyone is already a damn genius and can't look at something and say, "interesting, i'll keep that in mind" people think that because they've used mmo in their tractor before and it didn't clog the filter, then I must be wrong. well i assure you that this was no pipe dream of mine, it happened, and was happening to a second car. I guess it's just the dirty florida gasoline that only likes stainless filters. Maybe I'll have a mod change the thread title to that.

 

are you thinking about the miscibility?

it takes a LOT of oil for it to fall out of solution. I'm talking like when you mix a quart of gasoline in a gallon of oil.

Any oil will have molecules smaller than the finest filter.

I've seen tanks get varnished from sitting for as little as two years. Put fresh gasoline in it and the car will run, until it starts pulling the crap off of the sides of the tank, and then the fuel's burn characteristics change, and it runs leaner, often to the point where the car won't even start...

 

Was reading this.. and laughing at the defensiveness... BUT... Being from Florida.. St. Pete specifically.. I figured Id throw this out there..
Been pre-mixing for "Evar"
Never had any problems with filters clogging even with the stock filters.
Even when low on cash and using the crap 2-stroke oil from the Mobil/7-11/name it.
That is when at the races.. and driving all over th bay and realising you need to re-fill the tank.. and are out of 2-stroke.

I run 1 oz per Gallon. Rick Engman specifically said that is the best all around mix. This in one of many discussions at different events etc. I took his word on it years ago.. and have had ZERO problems.

Also another two racing rotary people.. who I trust with my automotive life.. like 99 percent of Rick's level skills wise.. Used to race rotaries through the early 70s till just recently. (They created some F500 and CSR/DSR cars).. They, in many discussions while working on things, have told me on many occations in Racing trim to throw the 1oz per gallon out the window!

They with many thousands hours of race motor time would add 2-stroke race oil to the gas in larger amounts.. keeping track.. and adjusting the fuel injection as they did.. until the car had a destinctly blue exhaust.. but power wasnt dropping.
They explained many many reasons.. some of these being, increasing the sealing in the combustion chambers from the literal thickening of the fuel. They also went into something regarding the BTU of the fuel because of the oil.. but I DO NOT want to get into a Internet arguement from all the armchair chemists about it.. I wasnt doing it..
BUT.. In the end.. the Lola chassis with 4 wheel steering and wings.. and a 13B with a street port, Bridge port, and PP housings.. with a 6 Barrel progressive throttle body.. and Bosch fuel injection on it.. owned Chimney rock hillclimb for many years.... until they kept lowering the DB requirements.. and they eventually had too much exhaust to be competitive.

In essence.. Yes.. 1OZ per Gallon is what I run. On my ITA car.. I run more than that. I will not say.. but YES I run more. Yes I still have the OMP.
On my EP motor.. I will be experimenting with the levels of pre-mix.

(Wow sorry for the long post.. typing on a break at work LOL)

 

^^^Thanks for the info^^^


How do you prevent this?

Also, I have a Aeromotive stainless filter before the fuel pump, but now I don't know which one I have (10 or 100) How can you tell?

Thanks

 

Also another two racing rotary people.. who I trust with my automotive life.. like 99 percent of Rick's level skills wise.. Used to race rotaries through the early 70s till just recently. (They created some F500 and CSR/DSR cars).. They, in many discussions while working on things, have told me on many occations in Racing trim to throw the 1oz per gallon out the window!

They with many thousands hours of race motor time would add 2-stroke race oil to the gas in larger amounts.. keeping track.. and adjusting the fuel injection as they did.. until the car had a destinctly blue exhaust.. but power wasnt dropping.


Racing Beat also recommends more premix as engine is stessed more; to the point of a 600HP 2 rotor being run at 29:1 ratio. That would be 1/2 gallon of premix to tank of fuel!

 

when running premix you also need to be careful of your afr ratios, as you add more oil, amoung other things you are reducing the amount of fuel that is being delivered into the engine which can cause it to run lean, it will also reduce the octane rating of the fuel. Was your engine tuned with the same type and amount of premix as it was running when it died? you may have been running leaner with lower octane fuel than you thought.

on another note there can be big differences in wear protection provided by tcw3 rated oils and infact alot of oils that arent tcw3 rated give much better wear protection

 

do the calculations and you'll relize that the octane reduction is very slight, not much of an issue

 

I have read the two stroke aviation guys that premix use this rough rule of thumb for calculating octane decrease-

Premix at a ratio of 50:1 drops your fuels octane rating by almost 2 points.

Quart of premix, pint of octane booster with your tank of gas and you are good to go, except for that being broke from the cost issue :P

 

no need for octane booster. Even if those calculations were accurate, no one should mix anymore than 1oz:1gallon which is 128:1. So your octane drops less than 1 point!

If you use a quart of premix in a tank of gas you're crazy!

 

I use a quart of premix per tank AND I have the stock OMP modified for max flow.

But I am crazy.

Racing Beat is even more crazy because they use 1/2 gallon of premix per tank on a 600hp 2 rotor...

Even more crazy is if you have a performance air cooled 2 stroke you mix as much as 1 gallon premix per 16 gallon tank like the aviation guys have to!