Allright you premixers and engine builders, racers and DDers etc etc blabla... Topic is premix oil, mixture-rates, apex seal types and wear on seals and housings.
What is your thoughts and experience on how important the mixture rate on 2-stroke oil when considering seal brand/type usage and housing wear? If we know the engine is well built and properly clearenced, how much will the 2-stroke oil mixture rate affect the housing wear?
Personally, i run a big streetport banzai racing built engine with RA superseals. I know they can hold up dynamite detonations, but their toughness comes at a price, housing wear, especially if the clearence job is poorly executed. Will a richer 2stroke oil mixture partially negotiate housing wear etc? I run 2% TCW-3 rated 2stroke oil, abit on the rich side yes, but it gives me peace in mind, allthough i have no proof it will reduce wear. Also, i run water injection and no OMP, so carbon build up is close to none.
Give me your thoughts, experiences, pictures etc. Im curious.

 

There is no scientific data to support anything other than lube is needed to keep the seals from warping and wearing so mazda developed the OMP.

However engine shops or builders will support and promote using premix along with using there favorite seal but you will be fine with just an OMP and stock seals if you drive the car at recommended boost levels.

OMP mix in 4 ounces per tank

NO OMP mix in 1 ounce per gallon or mix 1/2 ounce per gallon if you have lots of faith in your high dollar synth premix.

I've owned several FDs with over 100k miles that still had their original engines and typically these cars were not well cared for. The 13b is a tough engine outside of detonation. I'd say the avg life span of most turbo charged engines is right around 75k miles.

If you want your FD to last a long time premix and water injection are not the answer the answer lies in keeping it mostly stock with nothing but bolt ons and leave the boost at 10 psi and it will run a very long time if you maintain it properly.

Conversely: Over boosting is very dangerous and has been known to cause a permanent grin that is difficult to remove, is highly addictive and most importantly DANGEROUS to all those in the vicinity.

Is it worth the increased chance of catching on fire, wrecking, damaged engines, turbos, trans, diff, sticking solenoids, bushing wear etc.... YOU BETCHA!!!!!

 

I was running 3oz/gal during my breakin with the Superseals, and then 2oz/gal after the breakin. My builder/tuner/guy I TRUST recommended the higher premix amount to help offset the superseals reputation for eating housings.

The only thing with the higher premix amounts is that you will NEED legit coils.. I was fouling plugs with just the stock coils and an HKS Twinpower.

As Fritz alluded to, your best bet (if engine longevity is your goal) is to keep things relatively stock and/or under 400whp. If you're chasing all the horsepowers a little extra premix won't hurt though

 

This is what Mazda research produced for non-boosted engines.

 

For my engine warranty I recommend 8-12 oz per tank for modified cars with stock seals and functional OMP. The problem with the stock system is it injects oil only in the center of the seal, there that combined with the 2 piece seal is why higher mileage rotor housings tend to have excessive wear and chrome flaking at the outer edges. If you notice on the RX-8 MSP motors they went to 2 oil injectors per housing then 3 per housing in the later series 2 motors.

On modified cars with aftermarket seals I recommend 1z per gallon of gas.

With no OMP I recommend as much as you can without causing excessive smoke. This is usually 1.5-2 oz per gallon.

 

This thread has helped me a ton! I think I will keep the OMP but I wanted to start premixing to add more protection. I just need to make sure the same rule of thumb stands if I run E85.

 

How did they arrange the additional oil injectors per housing in the later RX-8 housings? Could the FD housings be modified to hold additional oil injectors?

 

Make sure you use an oil that handles the dilution properties of E85, and one that is TCW-3 rated.
Ask your local oil dealer

 

A thought on this... Cant remember what the tip looks like, but is it possible to either swap out or modify the tip of the oil injector to spread the oil more, kinda like the flat powerwasher tip that gives you a nice strong fan-spray?

 

fit FC 4 way EOMP and put the two spare squirts back into the primary inlet manifold
even better, tee them and put another pair also in the secondary runner

that is the only practical way of increasing lube to other parts of the seal other than premix

good thread
i see someone finally extrapolated the mazda SAE study to better numbers
and that people are switching on that it is oil directly to the apex seal where it is needed the most

supplement and OMP is the only way to go for those with aftermarket seals and higher HP

and ditching the OMP system entirely is a folly

 

1oz per gallon before I worked away from street driving. Even at the track I only do 1.5 oz per gal.

 

the other data we have is from the competition catalogs.

the 71-73 Rx3 (twin distributor engine), 130cc/hr @3000rpm, with the pump fully open.

the 1977 Rx3 manual wants 100 - 150 :1 pre mix.

and the 1979 is the same 100 - 150:1 pre mixed.

all the above are carbon seal engines.

the 787B also ran premix, and there is an SAE paper, i don't recall a mix ratio

 

Let's assume that 80cc per bank per hour means 80cc per rotor per hour.
If that is an incorrect assumption, please explain why.

As this was for a NA motor, lets say that for a boosted motor it is 120cc per rotor per hour.

One hour of semi-hard driving in a 2 rotor FD then should require 240cc (8 oz) of oil, 4 oz per rotor.

On the local track (PIR) let's say my average speed is 80 MPH.
During a track day my FD gets 7.5 MPG.

One hour of track time = 10.67 gallons of fuel.

At 8 oz per hour with 10.67 gallons of fuel, that is a ratio of 170:1

( 10.67 * 8 ) / 8 = 170.72

That is a premix of 4 oz per 5 gallons of fuel.

 

chart is for an S5, which is turbo

 

Barry stated it was NA

I don't have that doc, got a link to a PDF?

 

the graph states airflow.. which is both..
taking into account the 0-5v scale applied to the flow spread of the NA and the turbo airflow meters
effectively "leans" down the oil ratio for the turbo motor when at same volt return
( for the most part of the map and especially at that far end of the scale )

observation of the graph above shows that come about 3/4 along the airflow axis
.. they seem to have maxed the output
i guess that is mazdas lazymans way of negating the difference and making the EOMP "tune" to be universal between NA and turbo
as both will go to max output at 3.5 or more volts return on the AFM
, long before the scale difference between NA and turbo AFMs bites logarithmically

i expect also the position sensor body on the EOMP may be shimmed less on one version over the other
so that also fine tunes the offset difference
in a bid to match the one program algorithm to the differences in flow scale from the AFMs

the RPM axis of the graph will be purely the mechanical function of the EOMP being geared to crank speed
( the only control the ecu has is in using a stepper motor to open and close the inlet less or more on a mechanical OMP dose pump fixed with engine rpm )

i fully expect also the wide range TPS is used as a modifier for determining idle and maybe decel

but thinks the boost sensor itself is not used in anyway
.. as it complicates the universality of the single algorithm between NA and turbo
and is ( without an instant inlet temperature factor )
a less reliable 3D measure of load than the airflow meter already has provided


if you cant get you head around what i just said

basically it is very likely mazda chose one algorithm to use on both NA and turbo
and because the AFM is likely the "load" source used to determine the oil injection ratio
mazda have maxed oil flow at a point just past mid scale , when basically it is obvious both motors are going all out

engine speed has its own function to increase flow with revs
.. as it is still a mechanical pump , running at relation to engine speed , just like all the lever action omps of old

mazda fine tune the oil flow to the airflow of the end use by shimming under the feedback sender on the EOMP
( s5 FC NA, s5 FC turbo , 20b, 13bRE , 13bREW only )

the boost sensor is irrelevant ( in the s5 algorithm study above )
as it complicates the easy configure of a single unit and ecu components and program between the NA and turbo
and is also a less reliable way of gauging load than the airflow meter

the TPS is used ( but not indicated on the paper above ) to tell the ecu when at idle or decel
and quite possibly the program in the ecu will have look up values in tables to drop onto in these conditions

 

Large street port. Super Seals. E85
1oz per gallon of supertechniplate. I tend to get a little rich with the mix occasionally if there is only a few ounces left in my pint.
I run no OMP.
My car sees lots of limiter. This engine is going on 3 years of daily driving in the summer.

I think the E85 however is eating up oil control rings..... as well as rev limiter. This season it has began to consume more oil and smoke a bit more off throttle.