New Member RX-7 Technical Post your first technical questions here, in an easy flame free environment, before jumping into the main technical sections.

To use Premix or not

Thread Tools
 
Search this Thread
 
Old Nov 4, 2020 | 10:10 PM
  #1  
SleepyS4's Avatar
Thread Starter
Newbie
 
Joined: Nov 2020
Posts: 2
Likes: 0
From: WA
WA 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?
Reply
Old Nov 5, 2020 | 02:07 AM
  #2  
WANKfactor's Avatar
Instrument Of G0D.
Tenured Member: 10 Years
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: May 2011
Posts: 1,556
Likes: 997
From: omnipresent
It doesnt hurt.
Reply
Old Nov 5, 2020 | 07:03 AM
  #3  
Sgtblue's Avatar
Urban Combat Vet
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (16)
 
Joined: Oct 2003
Posts: 12,160
Likes: 983
From: Mid-west
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.

Last edited by Sgtblue; Nov 5, 2020 at 09:54 AM.
Reply
Old Nov 6, 2020 | 10:16 AM
  #4  
diabolical1's Avatar
Moderator
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (3)
 
Joined: Feb 2002
Posts: 10,998
Likes: 349
From: FL
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.
Reply
Old Nov 6, 2020 | 01:42 PM
  #5  
WANKfactor's Avatar
Instrument Of G0D.
Tenured Member: 10 Years
Liked
Loved
Community Favorite
iTrader: (1)
 
Joined: May 2011
Posts: 1,556
Likes: 997
From: omnipresent
Yeah sorry, I didnt even think of the cat as havnt had one for so long.Bit irresponsible of me.
Reply
Old Nov 6, 2020 | 05:22 PM
  #6  
TomU's Avatar
It Just Feels Right
Tenured Member 05 Years
iTrader: (11)
 
Joined: Feb 2014
Posts: 2,238
Likes: 349
From: Arlington, VA
So exactly how does premixing harm a cat?
Reply
Old Nov 6, 2020 | 06:22 PM
  #7  
diabolical1's Avatar
Moderator
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (3)
 
Joined: Feb 2002
Posts: 10,998
Likes: 349
From: FL
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.
Reply
Old Nov 6, 2020 | 08:31 PM
  #8  
Sgtblue's Avatar
Urban Combat Vet
Tenured Member: 20 Years
Liked
Loved
Community Favorite
iTrader: (16)
 
Joined: Oct 2003
Posts: 12,160
Likes: 983
From: Mid-west
Modern hi-flow cats are, apparently, more tolerant. But...

Catalytic Converter Failure: 3 Common Causes


https://www.walkerexhaust.com/suppor...ter-fails.html
Reply
Old Nov 7, 2020 | 09:57 AM
  #9  
Aaron Cake's Avatar
Engine, Not Motor
Tenured Member: 20 Years
iTrader: (1)
 
Joined: Feb 2001
Posts: 29,798
Likes: 128
From: London, Ontario, Canada
There's no reason to premix with a working metering oil pump on a stock car.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
dmolchanoff
New Member RX-7 Technical
5
Jan 22, 2009 08:05 PM
thecrow
New Member RX-7 Technical
19
Sep 19, 2008 08:37 PM
Lodivigo
2nd Generation Specific (1986-1992)
6
Nov 5, 2003 01:15 AM
2FAST7S
2nd Generation Specific (1986-1992)
3
Feb 18, 2002 11:50 AM




All times are GMT -5. The time now is 02:16 AM.