shocar

I have a new OEM 3-way cat in my rotary engine car. I am premixing at 150:1. I notice that when I park my car in the garage after running it to fully warm there is a distinct smokey odor coming from under the car. I have never checked to see if the cat is cherry red or anything like that!

I think that premixing is a good thing for the engine. When I premix, the engine runs quieter and revs more freely. I am noticing hardly any OMP oil use, but that may be because I have yet to start running WOT or even above 7K RPM.

So I am writing here to seek advice about the effect the premix would be having on the catalytic converter. I realize that if it burns out that I can get a hi-flow cat that may be more resistant to high termperature conditions. Have I just answered my own question? Or is there nothing to be concerned with?

I appreciate the advice available in this forum. There may be another forum in which this question may be more appropriate, but at this time I would not wish to start a new debate in that forum about the usefullness of premixing. However comments or advice of the same from other experienced RX7 owners would be welcome!

RotaryWeaponSE7EN

iTrader: (6)

Premixing is just like having the omp on. The premix u should use, should be ashless. So it shouldnt have any effect on the cats.

Edit: U can just hollow out the stock cats if u want.

diabolical1

iTrader: (3)

welcome ...

where in NY?
as stated, premix is fine. it won't kill your cat. how new is the cat? you may be smelling it, not the premix.

shocar

Thanks for the answers. I live in upstate central NY area. My new "cat" was purchased in Dec and has 2000 miles on it.

From what I understand premixing is not in style for others who may also have similar "cats". I know that it makes a difference with a new engine. I skipped the premix for 1 tankfull. I noticed a hot metal smell when I did that. I think that the cat was cleaning out soot that had been deposited in it. I think that the previously mentioned smokey odor was caused by the cat being overwhelmed by the premix. I have to keep a functional cat in the car because NY now has California level emissions laws. I think I will stay with the premix unless I hear otherwise about killing my cat. Thanks.

Marcus_F

Many aftermarket cats are dead in two years, so it may die on it's own anyway. That, and as others have said, a brand new cat will reek on it's own.

A point of concern; If I read your post properly, and you are adding premix to a car that has a functioning OMP system, you may kill the cat.

Lastly, if you have an electronic OMP, and it works anything like mine (and mine definitely works), you will use very little oil (via the OMP) during normal driving conditions.

813KR$

I have always heard it kills the cats?
I stay away from cats, so I really wouldnt know?

diabolical1

iTrader: (3)

did anyone ever offer a reason for saying that?

813KR$

I never listened, really? I dont like them, they restrict and are heavy, no use for me?

Aviator 902S

I think Marcus F has a point. If your running the stock omp, no problem. If you're pre-mixing, no problem. But if your pre-mixing AND running the stock omp simultaneously the engine is feeding twice as much oil to the apex seals as is necessary and in time could cause problems downstream.

Best bet is to remove the omp and install a block off plate over the omp mounting pad and then pre-mix with each fuel fill-up.

Or you can do what I did: Order an omp adapter from rotaryaviation.com and install that between the omp and the omp mounting pad. This unit blocks off oil flow from the pan and instead uses the stock omp to deliver 2-cycle oil to the apex seals via a separate reservior that you supply and install.

2-cycle oil burns cleaner and leaves fewer deposits behind, which is better for both the engine and the cat. Cost for this adapter is around $80 U.S. and takes about an hour to install along with the reservior.