To use Premix or not
11-04-20, 10:10 PM
#1
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To use Premix or not
Recently, I have purchased a 1988 GXL with about 32,000 miles on it, everything about it is pretty much new and all the gauges work. I saw Shooting Cars' video about premixing but I'm still a bit hesitate on using premix because the OMP works as it should but would it still prolong the life of the rotors? Or would it be more of a con to premix at such low miles?
11-05-20, 07:03 AM
#3
Do you have emissions where you live?
With a working OMP premixing at half-rate (guesstimating at the pump about a .5 oz @ gallon) can help a little with hard seal and housing wear and maybe a very little with dynamic compression.
The downside is it MAY, over time, shorten the life of your stock catalytic converter and if you have emissions testing neither a sub-performing cat or the additional burnt oil would be good.
It could also contribute to additional carbon build-up which can be an issue with rotaries.
It’s your call. But if it were my all-stock car I’d focus on cooling, changing out ALL fluids for fresh, maybe some plugs and keep the oil change intervals close to keep the oil your OMP is injecting as clean as possible...and enjoy the car.
My .02.
With a working OMP premixing at half-rate (guesstimating at the pump about a .5 oz @ gallon) can help a little with hard seal and housing wear and maybe a very little with dynamic compression.
The downside is it MAY, over time, shorten the life of your stock catalytic converter and if you have emissions testing neither a sub-performing cat or the additional burnt oil would be good.
It could also contribute to additional carbon build-up which can be an issue with rotaries.
It’s your call. But if it were my all-stock car I’d focus on cooling, changing out ALL fluids for fresh, maybe some plugs and keep the oil change intervals close to keep the oil your OMP is injecting as clean as possible...and enjoy the car.
My .02.
Last edited by Sgtblue; 11-05-20 at 09:54 AM.
11-06-20, 10:16 AM
#4
welcome to the board. 
first, congratulations on getting what sounds like a pretty sweet car. please put up some photos in the Intro sub-forum and (if you'd like) maybe a little something about yourself, too.
now, on to your question: both responses above mine are correct (in my opinion). Wankfactor's response should come with the caveat that Sgtblue's more comprehensive response covered though. that caveat is with regards to your cat. it's not a forgone conclusion that you will damage your cat by premixing with a functioning MOP, but it is worth your consideration. personally, i premix my rotaries and that is both with and without functioning MOPs. however, if you just plan on driving the car (as opposed to constantly beating on it), then you should be fine as you're vigilant with your oil changes and your MOP functions the way it should.
first, congratulations on getting what sounds like a pretty sweet car. please put up some photos in the Intro sub-forum and (if you'd like) maybe a little something about yourself, too.
now, on to your question: both responses above mine are correct (in my opinion). Wankfactor's response should come with the caveat that Sgtblue's more comprehensive response covered though. that caveat is with regards to your cat. it's not a forgone conclusion that you will damage your cat by premixing with a functioning MOP, but it is worth your consideration. personally, i premix my rotaries and that is both with and without functioning MOPs. however, if you just plan on driving the car (as opposed to constantly beating on it), then you should be fine as you're vigilant with your oil changes and your MOP functions the way it should.
11-06-20, 06:22 PM
#7
i have a heard a few theories on it. personally, 90% of them make no real sense to me, but the one that i lend at least a little credence to is essentially that it ends up creating a residue (that is obviously fuel-filled) that keeps burning inside it and eventually can lead to premature failure (over time, of course). another argument had to with ash vs. ash-less, but i never really looked into it much at the time when i did the little research i have done.
my Rx-8 was the only rotary that i actually had planned to keep the cat on. i premix it. now, when the cat failed (about 11 years ago), i had other issues, so i'm not attributing the failure to the premix. however, that was when i started hearing about premix being a possible cause. my coils crapped out on me, and the Rx-8 runs rich to begin with, so my belief is the cat died due to the combination of those things, but i kept the premix possibility in the back of my mind.
my Rx-8 was the only rotary that i actually had planned to keep the cat on. i premix it. now, when the cat failed (about 11 years ago), i had other issues, so i'm not attributing the failure to the premix. however, that was when i started hearing about premix being a possible cause. my coils crapped out on me, and the Rx-8 runs rich to begin with, so my belief is the cat died due to the combination of those things, but i kept the premix possibility in the back of my mind.
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11-06-20, 08:31 PM
#8
Modern hi-flow cats are, apparently, more tolerant. But...
Catalytic Converter Failure: 3 Common Causes
https://www.walkerexhaust.com/suppor...ter-fails.html
Catalytic Converter Failure: 3 Common Causes
https://www.walkerexhaust.com/suppor...ter-fails.html
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