Premixed fuel: good idea?
10-11-15, 11:50 PM
#51
But serious, a failing oil pump unlikely as it is is a bit scary.
Has anyone had one let go?
Do you get any warning when its on the way out, or even any sign that it has failed?
10-12-15, 06:05 AM
#53
Any one of these will instantly put the car into limp mode where fuel is pulled and timing won't advance unless vacuum is present in the intake manifold. What that effectively does is prevent you from boosting and retards power. You'll be able to get home...but that's it. And while it does this, the system defaults to 5v providing maximum oil to the OMP injectors. All these things combine to prevent internal engine damage.
If you really WANT to remove the OMP and go solely with pre-mix that is an option I and others laid out early in the thread. Your car, your call. But make that decision with accurate information.
OMPs will fail occasionally, yes. I had one go.
But on the FD there is not one but THREE CELs associated with the OMP. I don't think any other system is monitored as thoroughly. And all three would be shaded during a sensor check with a PFC.
And it's not "game over". As I recall, it's a 0 to 5v sensor dependent on load and rpm. When any problem appears it defaults to 5v, puts you into limp mode while providing max oil....
But on the FD there is not one but THREE CELs associated with the OMP. I don't think any other system is monitored as thoroughly. And all three would be shaded during a sensor check with a PFC.
And it's not "game over". As I recall, it's a 0 to 5v sensor dependent on load and rpm. When any problem appears it defaults to 5v, puts you into limp mode while providing max oil....
Last edited by Sgtblue; 10-12-15 at 06:08 AM.
10-12-15, 07:23 AM
#54
Thanks for that. Im running a 12a mechanical OMP (on an s5 engine in an FB) along with pre-mix. Just wondering if there's any way of knowing if the pump is healthy or not apart from running the lines into a beaker. Any tell-tail signs to look out for?
10-12-15, 08:14 AM
#55
i wouldn't bother looking for tell-tale signs. the MOP has an important function, but the damage that your engine will likely incur because of a failure is not likely to be a quick one. it would happen over time - probably a slow loss of compression. the pump's not going to fail today and the engine fails tomorrow. i suppose a quick death is a possibility, but i would also tend think other things (that either mean you're unlucky OR doing something you probably shouldn't be doing) would factor in greatly as well.
10-12-15, 08:22 AM
#56
i'm posting this separate just so no one thinks i'm singling anyone out, because i'm not. let's just try to keep the posts on topic. as a member, i usually don't mind watching things play out until someone says something to get themselves banned or their feelings hurt so bad that they quit, but i accepted the responsibility of being a moderator in this section and i do take that seriously as well, so let's disagree and even argue, but keep it on topic. i don't want to delete irrelevant posts and such, but as this is the New Members forum we need to keep things relevant and impersonal.
d1
d1
10-12-15, 10:01 AM
#58
with regards to those of us that have the mechanical MOPs and don't premix along with them, one of the things i had meant to say in post 55 was that it might not be a bad idea to maybe check the pump regularly, maybe with every tuneup. the test is fairly easy and the pumps are rebuildable.
10-12-15, 03:27 PM
#60
Anyhoo, another completely ******* rookie question regarding premix - is it worth paying double or triple the money for synthetic racing 2t oil? And if not, should we be running motorbike, outboard, or other?
Im using this because its relatively cheap and can be bought anywhere where i am
https://www.google.com.au/url?sa=t&r...C_pkbgkhGRxPgw
but thinking about switching to this or something else https://www.google.com.au/url?sa=t&r...04819420,d.dGY
10-13-15, 07:52 AM
#62
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does it matter which brand of fuel that you use? Is supermarket fuel poorer quality? https://www.jenningsforddirect.co.uk...he-facts/5149/
10-13-15, 01:06 PM
#63
it depends. everything up to a S5 car was mechanical and there are tests detailed in the FSM. if you have S5 car or newer, then it's electronic and tied into the OBD system. i don't know if there is a test for them or not, but as was said earlier, when they fail they will let you know. the car will go into limp mode and remain that way until the issue is addressed.
the older pumps can be rebuilt. i do not know if the electronic ones can though.
the older pumps can be rebuilt. i do not know if the electronic ones can though.
10-21-15, 05:02 AM
#67
here we go again...
the factory oil metering system actually causes wear tracks to develop in the rotor housings and carbon to develop more rapidly than just normal combustion causes.
2 stroke oil through the metering pump works better than the factory crankcase injection system does, since it's fresh oil and the proper type of oil, however the oil isn't spread as equally through the intake cycle as premixing.
i've torn apart engines that ran solely on premix for 50k+ miles and they had zero carbon deposits and the apex seals were wearing flat and even.
the factory OMP system does work ok, plenty of people have managed to get 200k+ miles from their engines with it. it has also caused some engines to fail earlier than a premixed engine would.
there is always pros and cons, not everyone likes to deal with premixing, however in my experience premixing will beat the OMP every time.
my experience? i've torn apart about 500+ engines and resurfaced hundreds of housings so i get to see where all the wear in the engine occurs. once you get up to 150k+ miles the wear track that begins at the metering port in the housing is almost always as deep as the chrome is thick. the RX8 renesis has injection ports on the sides of the rotor housings and if you're torn apart a number of early engines you know that the housing edges always wear rapidly, the RX8 multiplies this due to the oil injection system... bad idea, result is alot of completely trashed housings with as little as 70k miles on them. the additional wear in the renesis on the housings is not due to the multi-sideport either. the RX8 could benefit the most from premixing but don't tell those guys that, they love to argue(10 times worse than here, hence why i don't post there much otherwise i would be punching a lot of babies).
i haven't used an OMP on my car for about 10 years now.
this is a crappy picture but you can still see the center housing wear track which begins at the oil metering port in the housing, the wear varies depending on how dirty the inside of the crankcase is, meaning if you run your oil longer and dirtier then the wear will be more dramatic.
with the factory system the housings actually wear in an "M" shape.
the factory oil metering system actually causes wear tracks to develop in the rotor housings and carbon to develop more rapidly than just normal combustion causes.
2 stroke oil through the metering pump works better than the factory crankcase injection system does, since it's fresh oil and the proper type of oil, however the oil isn't spread as equally through the intake cycle as premixing.
i've torn apart engines that ran solely on premix for 50k+ miles and they had zero carbon deposits and the apex seals were wearing flat and even.
the factory OMP system does work ok, plenty of people have managed to get 200k+ miles from their engines with it. it has also caused some engines to fail earlier than a premixed engine would.
there is always pros and cons, not everyone likes to deal with premixing, however in my experience premixing will beat the OMP every time.
my experience? i've torn apart about 500+ engines and resurfaced hundreds of housings so i get to see where all the wear in the engine occurs. once you get up to 150k+ miles the wear track that begins at the metering port in the housing is almost always as deep as the chrome is thick. the RX8 renesis has injection ports on the sides of the rotor housings and if you're torn apart a number of early engines you know that the housing edges always wear rapidly, the RX8 multiplies this due to the oil injection system... bad idea, result is alot of completely trashed housings with as little as 70k miles on them. the additional wear in the renesis on the housings is not due to the multi-sideport either. the RX8 could benefit the most from premixing but don't tell those guys that, they love to argue(10 times worse than here, hence why i don't post there much otherwise i would be punching a lot of babies).
i haven't used an OMP on my car for about 10 years now.
this is a crappy picture but you can still see the center housing wear track which begins at the oil metering port in the housing, the wear varies depending on how dirty the inside of the crankcase is, meaning if you run your oil longer and dirtier then the wear will be more dramatic.
with the factory system the housings actually wear in an "M" shape.
Last edited by RotaryEvolution; 10-21-15 at 05:30 AM.
10-21-15, 09:55 PM
#70
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10-22-15, 04:54 PM
#73
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