Premix question
03-26-2018, 09:43 AM
#1
Registered
Thread Starter
Premix question
Hey guys, quick question.
I have never pre-mixed my RX-8 but I have decided that I am doing it from now on in order to preserve engine life.
I will be getting Idemitsu at some point, but have to order it in. In the meantime, for my next fillup (which will be in a couple days) I need a quick fix. Will this 2-stroke oil be ok for that purpose?
Lucas Semi-Synthetic 2-Cycle Oil, 946-mL | Canadian Tire
Most people suggest 0.5 oz per 1 gallon so I will go with that ratio.
I have never pre-mixed my RX-8 but I have decided that I am doing it from now on in order to preserve engine life.
I will be getting Idemitsu at some point, but have to order it in. In the meantime, for my next fillup (which will be in a couple days) I need a quick fix. Will this 2-stroke oil be ok for that purpose?
Lucas Semi-Synthetic 2-Cycle Oil, 946-mL | Canadian Tire
Most people suggest 0.5 oz per 1 gallon so I will go with that ratio.
03-26-2018, 10:09 AM
#2
SARX Legend
iTrader: (46)
That will be fine. Idemitsu being rotary specific is marketing nonsense, any JASO FD rated 2 stroke is fine. Remember, there is zero evidence that premixing does anything to extend the life of a Renesis.
03-26-2018, 02:14 PM
#3
I'll admit to being convinced by the idea that dirty engine oil seems like a comparatively worse idea than running clean oil in the combustion chamber, 2 stroke or otherwise. At least in theory.
Obvious side effects to the fuel system and you either need to run a Sohn or delete the OMP to fully eliminate dirty oil in the chambers aside, does this not track?
9k or otherwise, would you mind either elaborating on, or linking to a thread (preferably a post to start from, as there really are extensive threads on the subject) in which it is elaborated on? Thanks for your time.
03-26-2018, 02:45 PM
#4
SARX Legend
iTrader: (46)
I mean I premix and I run a SOHN just because in my mind it makes sense that it would help. But I have also seen my own and others premixed and SOHN equipped Rotaries loss compression and die just as fast as some bone stock cars. My original engine lasted only 22,000 miles, bone stock. My first reman lasted almost 75,000 miles, premixed when I would remember and stock aside from a catback.
And I also am no mechanical engineer, but I also understand that for there to be proof that either premixing or a SOHN did anything to prevent these engines from dying early, it would be a huge undertaking that will never happen.
Now, here is a pic from my own engine, you can see that the SOHN is keeping things clean. But the engine (Mazda reman) still died from a failed coolant seal at under 27,000 miles.
Now here is a buddies car, meticulously maintained, no SOHN, but premixed with Idemitsu. Mazda reman that died from low compression after like 25,000 miles.
And I also am no mechanical engineer, but I also understand that for there to be proof that either premixing or a SOHN did anything to prevent these engines from dying early, it would be a huge undertaking that will never happen.
Now, here is a pic from my own engine, you can see that the SOHN is keeping things clean. But the engine (Mazda reman) still died from a failed coolant seal at under 27,000 miles.
Now here is a buddies car, meticulously maintained, no SOHN, but premixed with Idemitsu. Mazda reman that died from low compression after like 25,000 miles.
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03-26-2018, 02:54 PM
#5
This makes sense to me as well, and thanks again.
I had a reman die in less that 10k kms from blown apex seal. Literally 13 months after replacement. I think the only thing I did to it was change the maps to shoot for RBT and adjust coil dwells because I was scared to run my Sohn on it from the previous engine losing compression.
As to OP. I run Lucas in my Sohn tank. Canadian Tire also sells Redline in 473ml bottles. I don't know what the technical difference between FD and FC rated oils are, but the bottle that is FD rated is blue/green, not red. The oil is still reddish, though.
I had a reman die in less that 10k kms from blown apex seal. Literally 13 months after replacement. I think the only thing I did to it was change the maps to shoot for RBT and adjust coil dwells because I was scared to run my Sohn on it from the previous engine losing compression.
As to OP. I run Lucas in my Sohn tank. Canadian Tire also sells Redline in 473ml bottles. I don't know what the technical difference between FD and FC rated oils are, but the bottle that is FD rated is blue/green, not red. The oil is still reddish, though.
03-26-2018, 03:17 PM
#6
SARX Legend
iTrader: (46)
This makes sense to me as well, and thanks again.
I had a reman die in less that 10k kms from blown apex seal. Literally 13 months after replacement. I think the only thing I did to it was change the maps to shoot for RBT and adjust coil dwells because I was scared to run my Sohn on it from the previous engine losing compression.
As to OP. I run Lucas in my Sohn tank. Canadian Tire also sells Redline in 473ml bottles. I don't know what the technical difference between FD and FC rated oils are, but the bottle that is FD rated is blue/green, not red. The oil is still reddish, though.
I had a reman die in less that 10k kms from blown apex seal. Literally 13 months after replacement. I think the only thing I did to it was change the maps to shoot for RBT and adjust coil dwells because I was scared to run my Sohn on it from the previous engine losing compression.
As to OP. I run Lucas in my Sohn tank. Canadian Tire also sells Redline in 473ml bottles. I don't know what the technical difference between FD and FC rated oils are, but the bottle that is FD rated is blue/green, not red. The oil is still reddish, though.
Yeah man, over the last 13+ years I have seen many fail. Just locally three or four of us long time owners have went thru 12-15 remans, many of those stock. My buddy had one that lasted a couple of days and I know Alnielson (mod) and some other OG members here have also had a couple of engines that lived shorter lives than yours.
People don't like to admit it because one out of 1000 Renesis engines makes it to 100,000 miles but these engines are just an inferior design and it is what it is. The sooner one accepts that, the easier their ownership will be.
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03-26-2018, 06:07 PM
#8
I've seen this sentiment being expressed in several areas now on the club, and I was wondering why it's been coming up so often. I understand that there's "no evidence" insofar as studies/peer review-able data, but can't the same be said for a bunch of the crap we do for "longevity". Most of it comes down to anecdotal evidence at best. I don't even really know how one would go about providing said evidence.
So the question is, what do you do in the absence of good evidence? Do you pretend weak or dubious evidence and reasonable-sounding ideas are good enough, or do you put the idea on the shelf until good evidence comes around?
I'll admit to being convinced by the idea that dirty engine oil seems like a comparatively worse idea than running clean oil in the combustion chamber, 2 stroke or otherwise. At least in theory.
Obvious side effects to the fuel system and you either need to run a Sohn or delete the OMP to fully eliminate dirty oil in the chambers aside, does this not track?
Obvious side effects to the fuel system and you either need to run a Sohn or delete the OMP to fully eliminate dirty oil in the chambers aside, does this not track?
On the flip side, whether you premix, run a Sohn, or whatever, you have no idea whether you're using the right amount of premix at any given time. It's all just guesswork. Plausible guesswork, but guesswork. The kind of testing that'd be necessary to figure it out for real is beyond the means of pretty much everyone who cares. That means no one knows whether the net effect is positive, negative, or neutral. A lot of people seem to think "positive" is a safe bet, which is completely plausible. But they don't know.
Anyone is free to spend time and money tinkering with some of the most important parts of their engine and hope it increases longevity. If they want to do so on no basis other than "this idea makes sense and occasionally correlates with a long-lived engine", that's their privilege. Can't blame anyone for that. But if you're the type to need evidence before you do something serious, it's not enough.
03-26-2018, 10:51 PM
#9
It does, 100%.
On the flip side, whether you premix, run a Sohn, or whatever, you have no idea whether you're using the right amount of premix at any given time. It's all just guesswork. Plausible guesswork, but guesswork. The kind of testing that'd be necessary to figure it out for real is beyond the means of pretty much everyone who cares. That means no one knows whether the net effect is positive, negative, or neutral. A lot of people seem to think "positive" is a safe bet, which is completely plausible. But they don't know.
On the flip side, whether you premix, run a Sohn, or whatever, you have no idea whether you're using the right amount of premix at any given time. It's all just guesswork. Plausible guesswork, but guesswork. The kind of testing that'd be necessary to figure it out for real is beyond the means of pretty much everyone who cares. That means no one knows whether the net effect is positive, negative, or neutral. A lot of people seem to think "positive" is a safe bet, which is completely plausible. But they don't know.
Does anyone know how well premix stays in suspension? I mean, if you run through your tank fairly frequently you can reasonably estimate that you're getting a fairly good mix. But if the oil falls out of suspension overnight, that's a bit of a problem...
03-27-2018, 04:49 AM
#10
I have a different take on the whole thing .
Mazda designed an OMP system as best they could to meet three vastly different design criteria :
1/to lubricate all that needs to be lubricated within the combustion camber
2/to meet emissions
3/to make it idiot proof
They succeeded for the most part ...for as we know , these engines CAN last well over 100k miles .
To meet emissions they had to minimise oil consumption as much as they possibly could . In so doing they cut back the level to barely adequate . This became evident when in the early days they had many premature failures for low compression. What did they do to address this ? Increase the amount of oil injected . Low and behold this actually worked to a large extent but they still were limited as to how much extra they could put in . In the later engines they added a nozzle as this allowed more accurate placement of the oil thereby allowing less oil to be used . That doesn't mean the early design was flawed ...just that it needs more oil to do the job properly than the later design .
From this plus 13 years of ownership , 240,000kms (140,000 of these turboed) and obeservations from several engines torn down I have devised my own solution to the Renesis oiling issue:
*Add more oil via an ECU reflash (I add 10% over most of the map but go from 3 to 4 on the map in certain critical cruise areas)
*Do regular oil changes ( around every 4000 miles should be ample)
*Use synthetic oil because it holds all it's properties between oil changes
*Monitor oil useage to make sure you are using the right amount of oil between changes
*Regularly inspect omp hoses to ensure are flowing clean oil and there are no leaks .
*Fit a catch can and vent sump to atmos. so the intake and injection nozzles don't see the gunk that clogs them up.
As far as premixing and the Sohn goes .............. you guys are welcome to it . I can see why many think it's beneficial , but to me the above actually makes more sense.
Mazda designed an OMP system as best they could to meet three vastly different design criteria :
1/to lubricate all that needs to be lubricated within the combustion camber
2/to meet emissions
3/to make it idiot proof
They succeeded for the most part ...for as we know , these engines CAN last well over 100k miles .
To meet emissions they had to minimise oil consumption as much as they possibly could . In so doing they cut back the level to barely adequate . This became evident when in the early days they had many premature failures for low compression. What did they do to address this ? Increase the amount of oil injected . Low and behold this actually worked to a large extent but they still were limited as to how much extra they could put in . In the later engines they added a nozzle as this allowed more accurate placement of the oil thereby allowing less oil to be used . That doesn't mean the early design was flawed ...just that it needs more oil to do the job properly than the later design .
From this plus 13 years of ownership , 240,000kms (140,000 of these turboed) and obeservations from several engines torn down I have devised my own solution to the Renesis oiling issue:
*Add more oil via an ECU reflash (I add 10% over most of the map but go from 3 to 4 on the map in certain critical cruise areas)
*Do regular oil changes ( around every 4000 miles should be ample)
*Use synthetic oil because it holds all it's properties between oil changes
*Monitor oil useage to make sure you are using the right amount of oil between changes
*Regularly inspect omp hoses to ensure are flowing clean oil and there are no leaks .
*Fit a catch can and vent sump to atmos. so the intake and injection nozzles don't see the gunk that clogs them up.
As far as premixing and the Sohn goes .............. you guys are welcome to it . I can see why many think it's beneficial , but to me the above actually makes more sense.
Last edited by Brettus; 03-27-2018 at 04:54 AM.
03-27-2018, 08:41 AM
#11
I know this has been beat to death but this is my impression, correct me if I am wrong:
-Rennies have several known failure modes: coolant seals, side seals, apex seals (more?)
-OMP applies oil ONLY to the apex seals (and side seals?)
-premix 'assists' the OMP and 'may' extend the life of the apex seals vs. OMP only
Renny failure due to coolant seals, etc is unaffected by premix. Renny failure specifically due to worn apex seals may be reduced by premix. Premix is known to increase compression numbers over non-premix, thus the guide to run straight gas when having the engine compression tested.
Premix 'assists' the OMP and is an insurance policy in the event of a non-functional OMP, i.e. bad pump, lines, oil injectors. And we have certainly seen plenty of those.
-Rennies have several known failure modes: coolant seals, side seals, apex seals (more?)
-OMP applies oil ONLY to the apex seals (and side seals?)
-premix 'assists' the OMP and 'may' extend the life of the apex seals vs. OMP only
Renny failure due to coolant seals, etc is unaffected by premix. Renny failure specifically due to worn apex seals may be reduced by premix. Premix is known to increase compression numbers over non-premix, thus the guide to run straight gas when having the engine compression tested.
Premix 'assists' the OMP and is an insurance policy in the event of a non-functional OMP, i.e. bad pump, lines, oil injectors. And we have certainly seen plenty of those.
03-27-2018, 09:39 AM
#12
SARX Legend
iTrader: (46)
Yeah, many failure modes and I agree with Brett on increasing the OMP rates VIA the tune and changing the oil as often as possible using a quality oil.
But it's all guess work for the most part since I have known plenty of FD guys who swore by some of these same methods on built engines only to also have them **** the bed for one reason or another. And in my experience in being a part of many tear downs, the only failure I have ever seen that was lubrication related, was on a very neglected RX-8.
My current engine built by Pineapple has been boosted since day one and premixed and SOHN since day one and it still going strong after 7 years, but mileage wise it has not outlived my first reman yet so we shall see. But Pineapple did do oil system mods like porting the oil passages, increasing the oil pressure, etc. And let's not forget, the oil metering system is as much about cooling as it is about lubrication.
But there is no clear blueprint on how to make a Renesis last as some of those who have made it past 100k did nothing aside from normal maintenance and used cheap 5W-30 the whole time. But those people are rare.
But it's all guess work for the most part since I have known plenty of FD guys who swore by some of these same methods on built engines only to also have them **** the bed for one reason or another. And in my experience in being a part of many tear downs, the only failure I have ever seen that was lubrication related, was on a very neglected RX-8.
My current engine built by Pineapple has been boosted since day one and premixed and SOHN since day one and it still going strong after 7 years, but mileage wise it has not outlived my first reman yet so we shall see. But Pineapple did do oil system mods like porting the oil passages, increasing the oil pressure, etc. And let's not forget, the oil metering system is as much about cooling as it is about lubrication.
But there is no clear blueprint on how to make a Renesis last as some of those who have made it past 100k did nothing aside from normal maintenance and used cheap 5W-30 the whole time. But those people are rare.
03-27-2018, 09:57 AM
#13
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Thread Starter
Wow, interesting comments. The reason I have decided to premix is because I realized it makes complete sense that it will help lubricate the seals along with the OMP and my engine has slightly low compression but seems to run well and while I know its not going to increase compression I want to at least keep the engine in the condition its in for now. Anyways, I went ahead and purchased Idemitsu from Ebay (Mazdatrix) instead, figured I would go with that.
03-27-2018, 10:02 AM
#15
FULLY SEMI AUTOMATIC
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03-27-2018, 10:33 AM
#16
Sohn adapters source
03-27-2018, 10:42 AM
#17
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Thread Starter
Oh, I see! I get it, so basically a SOHN adapter injects 2 stroke oil into the combustion chamber, meaning you dont need to premix, got it.
03-27-2018, 10:47 AM
#18
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Well, whether or not you need premix is a long and obnoxious argument.
Without the Sohn adapter, you're still injecting lubricant. The difference is that you're injecting engine oil. So, if you think you need to premix without the Sohn adapter, then you probably still need to with the Sohn adapter.
The Sohn just allows you to change what you inject (cleaner burning oil that contains less non-combustible material).
Without the Sohn adapter, you're still injecting lubricant. The difference is that you're injecting engine oil. So, if you think you need to premix without the Sohn adapter, then you probably still need to with the Sohn adapter.
The Sohn just allows you to change what you inject (cleaner burning oil that contains less non-combustible material).
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bwilk (03-27-2018)
03-27-2018, 02:01 PM
#19
Forgot to mention ............... I did an experiment on an engine where I halved the OMP rate . I calculated that if I added premix at 200:1 the engine would be using approx. the same amount of oil as if the omp was still at full at full strength. This engine lasted approx 60,000 kms before it became too hard to start.
When we tore it down ......... we found the side plates were badly scored all over and there were gouges (from the corner seals) beside all the exhaust ports . It had failed through................... lack of lubrication !
From this I made a couple of conclusions :
1/If using premix .....200:1 does F'all to protect the engine. You need 100:1 to provide decent lubrication from premix.
2/A fully functioning OMP at full strength in all probability , does a better job at lubricating the side/corner seals than premix can ever do.
From then on I decided to just up the omp rate and can premixing all together.
When we tore it down ......... we found the side plates were badly scored all over and there were gouges (from the corner seals) beside all the exhaust ports . It had failed through................... lack of lubrication !
From this I made a couple of conclusions :
1/If using premix .....200:1 does F'all to protect the engine. You need 100:1 to provide decent lubrication from premix.
2/A fully functioning OMP at full strength in all probability , does a better job at lubricating the side/corner seals than premix can ever do.
From then on I decided to just up the omp rate and can premixing all together.
03-27-2018, 02:10 PM
#20
The thing with premix is that a large portion of it does no useful lubrication. Some of the oil you put in goes straight out the tail pipe, a bunch more ends up on the rotor and performs no useful function before burning off, and only a fraction lands in an area swept by any seal. So if you premix the same amount as is injected by the OMP, the OMP wins because all of its oil goes to a seal.
That said, I don't see how OMP oil can climb the side seal against centrifugal force. Premix seems like a better method to lubricate and cool that area. So I run MazdaManiac OMP rate and premix 200:1 for street, some more for track. This could all be ill advised, won't know until the engine has to come out.
That said, I don't see how OMP oil can climb the side seal against centrifugal force. Premix seems like a better method to lubricate and cool that area. So I run MazdaManiac OMP rate and premix 200:1 for street, some more for track. This could all be ill advised, won't know until the engine has to come out.
Injectors and pumps are cheap, right?
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Brettus (03-27-2018)
03-27-2018, 06:02 PM
#24
Smoking turbo yay
On a serious note, though, I have read that too much premix can bring down the octane number. I personally stick with 1:200 to 1:250 right now.
Another thing to consider is that, since premix is in the gas, if you engine brake and release the gas pedal, there will be no premix. You would be relying on the OMP.
Last edited by UnknownJinX; 03-27-2018 at 06:06 PM.