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The rotary engine is a unique animal, combining low compression ratios with high combustion temperatures. It also requires a fuel that can deliver lubrication to the apex seals. Since that sounds like a tall order for the fuel, we asked for product recommendations from someone who knows championship Mazda race cars: Jesse Prather of …
What you mean it's not unicorn blood and whale blubber?
I kid...
Can you use castor oil premix on these? That smell might make the brappy experience irresistible to me.
How would one do on methanol? That ought to lower combustion temperatures...
Money.
MadScientistMatt said:How would one do on methanol? That ought to lower combustion temperatures...
Only if you have double the fuel capacity to inject and port volume to accommodate....
And I'll admit, this was one of the more challenging ones to do.
In reply to Carbon (Forum Supporter) :
I used to build Open Mod snowcross engines for snowmobile racing, the only two premix oils that we never had crankshaft problems while running were the Ski-Doo XPS full synthetic injection oil, and Redline Two Stroke Race Oil. Personally, I think the Redline smells even better than castor oil, and burns super clean. So you can have your great smell AND clean seals at the same time!
this is why i run 89 pump, its always E10 and for non turbo it doesn't matter, hell i should even do 87
Carbon (Forum Supporter) said:Can you use castor oil premix on these? That smell might make the brappy experience irresistible to me.
You can, but they leave disgusting thick tarry deposits that cause issues.
Pete. (l33t FS) said:Carbon (Forum Supporter) said:Can you use castor oil premix on these? That smell might make the brappy experience irresistible to me.
You can, but they leave disgusting thick tarry deposits that cause issues.
In that case run 927 which is a blend of synthetic and de-gummed castor.
No goo, no deposits, and none of the bad things associated with straight castor
MadScientistMatt said:How would one do on methanol? That ought to lower combustion temperatures...
Apparently there are people making 450hp from a two rotor on methanol. Naturally aspirated.
Nitpick. Rotaries have low combustion temperatures. That us why they are naturally low in NOx production. They have high EGTs because of the way the exhaust ports open, and how they can make a lot of power at relatively lean fuel ratios. Some racers would run lean of stoich at WOT!
After going to a standalone using a EFR 7176 twin scroll turbo, I upgraded everything with all purposes towards managing heat (upgraded entire fuel system, oil system, electriconics, cooling system, etc.)!
So I also had the car flex-fuel tuned. And I did my own testing of pre-mixes with the E-85 I was running (mix suspension test, burn test, residue test) and found that only one pre-mix worked absolutely awesome with Ethanol based fuel (in my case - never below E-78). Redline makes a pre-mix for alcohol fuels, and it works. I still, 2 years later, have a sealed jar in my garage with E-85 and the Redline Alcohol pre-mix suspended in it. Everything else separated and/or left a horrible residue after burning: (AMS Oil, Idemitsu (sp?), cheap 2-cycle from Lowes, Pettit Racing, and a couple Castor based that I don't have anymore so I don't remember the brands). I ran 2oz of premix per gallon, and I had zero issues and the car was injector limited on power produced.
New owner loves the car and upgraded injectors (took the 1700 secondaries to primary, and added 2600 in secondaries and had it tuned by someone else, car is putting down nearly 500whp now flawlessly (my setup was 360whp.)
In reply to Raszaron :
At least with regards to the solubility of E85 pre-mix, I found that Redline 2-Cycle Alcohol Oil, Klotz Original TechniPlate (KL-200), and Motul Micro 2T all remained in solution:
Spic Racer GT40R - Page 15 - RX7Club.com - Mazda RX7 Forum
That said, would love to hear how you residual, and burn tested the sample oils.
In reply to Rotary_Pilot :
An interesting thing I read is that anything castor-based needs to be used right away, or the castor oil will degrade. "Right away" meaning within a day of mixing. When it degrades, lubricity goes away fast, and it also leaves thick tarry deposits everywhere... sounds familiar?
Not something you premix and then forget about.
To be honest, I'd think alcohol fueled engines would be a great reason to run a MOP with an external tank so it feeds 2 stroke oil, not crankcase oil. Maybe modify one/double them up somehow so that you can increase the amount of oil injected, as Mazda really did not inject enough oil for best power even at stock power levels.
Racing Beat found that in a turbocharged engine in the power levels we are talking about here, they found best results in the 6oz/gallon range, on gasoline. That is roughly 20:1 fuel:oil. So about 15-10:1 on alcohol, unless I did my math wrong. (narrator: he did. he meant roughly 30-40:1 on alcohol)
My 270-ish horsepower bridge port 13B gets fed 50-60:1 premix, and I never see any deposits. I stop there because more oil than that makes the exhaust visible 
I also have a stock port 12A with immaculate rotor housings, a rarity nowadays, and it has a working MOP with the adjuster arm maxed out, AND I premix at about 120:1. With the working MOP, I use Motorcraft oil made for Diesels with particulate filters, because I figure it has really low ash content. And it's cheap.
Pete. (l33t FS) said:Apparently there are people making 450hp from a two rotor on methanol. Naturally aspirated.
Was it this car?
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