Rev up the engine for shutdown
05-21-2011, 09:35 PM
#1
Rev up the engine for shutdown
Just got my 2009 R3 couple days ago, went to the dealer yesterday to just get briefed on basic maintenance. The guy I talked to owned a Rx for some time and clearly had a deep enthusiasm for it. One the things he was very strong about was while in neutral, rev up the engine to at least 7k and right then turn the engine off. I have never heard of this, and I told him that, but he was pretty serious about it. He explained that it is supposed to get all combustion chamber clear for shutdown to prevent flooding in a proactive way. I'm fine with the idea, but it's noisy to many people including my neighbors who i'm not exactly famous with. But really, my main concern is it really doing good things for the engine?
05-21-2011, 09:48 PM
#2
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Not really necessary AFAIK. Never turn off the engine while its cold, or it will probably flood next time you start. Other than that, take the RPM to the redline about once a day (if you drive daily) to clear out the carbon (while in gear, not neutral)
Last edited by waleed786; 05-21-2011 at 09:57 PM.
05-21-2011, 09:48 PM
#3
The X is silent
I'll be the first worm out of the can...
In short order, yes, it is beneficial to your engine for this exact reason. However, there is more:
-Dont rev it too high before it is fully warmed up
-Dont shut it down before it's warmed up
-You need to redline it regularly while driving it for this same effect, and this can reduce the necessity to do it around your neighbors.
I'm sure I've missed a few things, and this is very generic advise, which some people will swear by and others will say is BS. Long story short: reving your motor is GOOD for it, as long as it is warmed up.
To learn more, I recommend the "Search" function, or simply Google.
-So much for my "perfect" post count-
In short order, yes, it is beneficial to your engine for this exact reason. However, there is more:
-Dont rev it too high before it is fully warmed up
-Dont shut it down before it's warmed up
-You need to redline it regularly while driving it for this same effect, and this can reduce the necessity to do it around your neighbors.
I'm sure I've missed a few things, and this is very generic advise, which some people will swear by and others will say is BS. Long story short: reving your motor is GOOD for it, as long as it is warmed up.
To learn more, I recommend the "Search" function, or simply Google.
-So much for my "perfect" post count-
05-21-2011, 11:10 PM
#5
I knew not to listen to my dealer as soon as he told me that oil changes on the rx8 are to be done every 7500 miles. On top of that they send me "maintenance reminders" .... they assume that in the one year of ownership I have 14k miles .... they have only sent me two "reminders" ... get my drift?
05-21-2011, 11:13 PM
#6
The X is silent
So there is no benefit to either aspect, whatsoever?
Does it negatively affect the motor, whatsoever?
Proof? Maybe even a reference?
Sometimes it's about what you've read from multipe reputable sources vice IQ. I wont pretend to be a rocket scientist, but merely a humble Nuclear Engineer.
Either way, I love reading reliable information about rotary engines. I'm not calling you unreliable... I just want proof.
05-21-2011, 11:16 PM
#7
The X is silent
I knew not to listen to my dealer as soon as he told me that oil changes on the rx8 are to be done every 7500 miles. On top of that they send me "maintenance reminders" .... they assume that in the one year of ownership I have 14k miles .... they have only sent me two "reminders" ... get my drift?
05-21-2011, 11:41 PM
#9
People that today have flooding issues either don't have the latest program in the ecu or they have a weak ignition system that is leaving too much raw fuel in the chamber when the car is turned off.
In 7 yrs of ownership, my car has never flooded. And, I do everything they say you shouldn't.
In 7 yrs of ownership, my car has never flooded. And, I do everything they say you shouldn't.
05-22-2011, 01:02 AM
#12
The X is silent
I "understand" the operation of the motor, and the theory behind the operation in question.
I asked two questions for the sake of intelligent discussion, and rather than answer them, you hit the "noob" button, even when I indicated that the questions were being asked respectfully.
What am I to "understand" from that?
MY POINT IS:
From an engineering perspective, I dont see a disadvantage to performing this procedure before shutdown. It is better to error in favor of caution, correct? The only possible way I could see this causing damage to the motor, is if it continues to spin after the electric OMP and fuel injectors shut off, which would cause unnecessary wear on the apex seals. To prevent, Mazda could have used a mechanical OMP, Like they did in the S4 RX-7, but we would lose adjustability in tuning. Besides that, it wouldnt be terribly difficult to program the ECU to run the electric OMP and fuel injectors until the motor is stopped, right? So, again, I dont see a reason to not perform the operation, given that most people are using whatever tune they came on their car, and haven't upgraded to BHR coils. There are RX-8 flooding on here, every day.
Fair point? I'm open for logical, rational arguments against this point. If anyone can provide one, I am willing to listen, and I thank you for your direction.
PS: Thanks for chiming in, Al. I like seeing productive posts that answer honest questions.
05-22-2011, 01:17 AM
#13
Considering that you dabbled in the "engineering perspective", I will go out and assume that you have an engineering background.
The proper question would have been "from an engineering perspective, I don't see an advantage to performing this procedure". As engineers, our principles are to PROVE why we DO something, rather than DO and try to PROVE why not to do it
In any event, the reason why the noob button was pressed so to speak, is because for a forum that has been around since 2003, and a principle design of a motor that has been around long before that, one would expect that somewhere, someone had to have asked this question and had it answered by now.
The proper question would have been "from an engineering perspective, I don't see an advantage to performing this procedure". As engineers, our principles are to PROVE why we DO something, rather than DO and try to PROVE why not to do it
In any event, the reason why the noob button was pressed so to speak, is because for a forum that has been around since 2003, and a principle design of a motor that has been around long before that, one would expect that somewhere, someone had to have asked this question and had it answered by now.
05-22-2011, 02:45 AM
#14
Well Stated...
In any event, the reason why the noob button was pressed so to speak, is because for a forum that has been around since 2003, and a principle design of a motor that has been around long before that, one would expect that somewhere, someone had to have asked this question and had it answered by now.
Last edited by Grace_Excel; 05-22-2011 at 03:04 AM.
05-22-2011, 04:06 AM
#15
The X is silent
^ I suppose I could have said "I recognize only advantages to using this procedure," and offered theory backing the statement, but the spirit of the statement doesn't change. "Doing A" or "Doing B by not doing A" is an argument in semantics, "Doing B is not doing A" any way you slice it.
I want to know if there is a major disadvantage to using the procedure in question. This particular question has been asked in passing, but never addressed. It seems like the only reason it has met resistance is because of its basis in (what should be) an outdated problem. I can't seem to find a legit reason to not perform it (for instance, if you know your coils are getting weak).
I know exactly why the "Noob" button was punched... It was because someone got butt-hurt when their ego was challenged (which I find ironic, given his "Location.")
God forbid the "edgy guy" feels a little sore in the rear.
I make it a point to be as respectful as I can be on here. I dont mind being told that I'm wrong if it is the case, but if it's not backed up, its BS.
I want to know if there is a major disadvantage to using the procedure in question. This particular question has been asked in passing, but never addressed. It seems like the only reason it has met resistance is because of its basis in (what should be) an outdated problem. I can't seem to find a legit reason to not perform it (for instance, if you know your coils are getting weak).
I know exactly why the "Noob" button was punched... It was because someone got butt-hurt when their ego was challenged (which I find ironic, given his "Location.")
God forbid the "edgy guy" feels a little sore in the rear.I make it a point to be as respectful as I can be on here. I dont mind being told that I'm wrong if it is the case, but if it's not backed up, its BS.
05-22-2011, 07:40 AM
#17
Anybody who looks up to the Mazda dealership/service rep for guidance gets what they deserve ?
I want to know if there is a major disadvantage to using the procedure in question. This particular question has been asked in passing, but never addressed. It seems like the only reason it has met resistance is because of its basis in (what should be) an outdated problem
Yes, I think it's safe to assume they've come a long way by the time 2009 came by to negate this procedure as a necessity. And I appreciate everyone's involvement in the conversation but the question has not really been answered:
Do I need to be doing this all the time? Is it ok if I come home from work at 10pm and just quietly turn it off?
I can do it some of the time, I have no issue with that. But if I'm in a parking lot and a woman is loading a 5 month old baby into her car next to me, I don't want to be 1)inexcusably rude 2) or compromise the health of this car. That's just an example, but those are pretty fundamental reasons for why/why not. I like doing it, and if there's a bunch of nice girls a throwing distance away, you better believe I'll do it. I just want to know if I should feel like Im abusing my RX if occasionally i just shut down.
Last edited by diomedes; 05-22-2011 at 07:43 AM.
05-22-2011, 08:36 AM
#18
^ I suppose I could have said "I recognize only advantages to using this procedure," and offered theory backing the statement, but the spirit of the statement doesn't change. "Doing A" or "Doing B by not doing A" is an argument in semantics, "Doing B is not doing A" any way you slice it.
I want to know if there is a major disadvantage to using the procedure in question. This particular question has been asked in passing, but never addressed. It seems like the only reason it has met resistance is because of its basis in (what should be) an outdated problem. I can't seem to find a legit reason to not perform it (for instance, if you know your coils are getting weak).
I want to know if there is a major disadvantage to using the procedure in question. This particular question has been asked in passing, but never addressed. It seems like the only reason it has met resistance is because of its basis in (what should be) an outdated problem. I can't seem to find a legit reason to not perform it (for instance, if you know your coils are getting weak).
1) 7k rpm is way too high. The apex seals are held in place in part by combustion chamber pressure. No-load revving generates rpm without increasing the chamber pressure = bad.
2) It bothers onlookers and makes you look like a dope.
3) It wastes fuel.
4) It's bad for emissions.
Advantages:
1) It adds to the cult-like feeling of being an insider.
2) It's a ritual, esp pleasing to OCDs.
3) It's an ego boost ('I know something you don't know.')
Choosing to do something based on the idea it might be beneficial if not harmful is not a substantial reason for doing it.
Examples:
1) I'll bet no RX-8 engine has failed while a large blue "X" in painters tape stuck on the hood, so why not add it to your car?
2) A rabbit's foot in the pocket might be lucky and does no harm (except for the rabbit), so why not?
3) If 3,000 mile oil change intervals are better than 7500 miles, then why not 300 mile oil changes?
Most old-tech piston aircraft engines have a very specific shutdown procedure that involves increasing the rpm a bit above idle before pulling the mixture to cutoff. The reasons for doing so are known and the procedure is specified by the manufacturer. That's a good reason for doing so, not ritual legend.
05-25-2011, 12:37 AM
#19
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05-25-2011, 02:01 PM
#20
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I think No one here can give you the awnser you are serching for but to add to the information mess:
The ONLY time I will do this procedure is if I just moved the car, Ill let it heat up so one set of bar disapear, then holt it a 3500 and shut it down, Understanding the benefit of having the rotors turn freely for an additionnal 2-3 sec without fuel injection, venting the chamber.
7000rpm I find it too high bercause "I beleive" when you shut down the car, The OMP stops, so no oil injection = bad.
If you have driven it anyting more than 10-15min, you do not need this procedure. " To My Own Belief "
Take what you want of this info, Ive had a 04 and now a 09 R3 and have never flooded them once, Had the occasionnal long crank on both both nothing to serious.
The ONLY time I will do this procedure is if I just moved the car, Ill let it heat up so one set of bar disapear, then holt it a 3500 and shut it down, Understanding the benefit of having the rotors turn freely for an additionnal 2-3 sec without fuel injection, venting the chamber.
7000rpm I find it too high bercause "I beleive" when you shut down the car, The OMP stops, so no oil injection = bad.
If you have driven it anyting more than 10-15min, you do not need this procedure. " To My Own Belief "
Take what you want of this info, Ive had a 04 and now a 09 R3 and have never flooded them once, Had the occasionnal long crank on both both nothing to serious.
10-31-2011, 12:16 PM
#21
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Reving before shutdown
I've owned Mazda Rotaries since 1973. I'm on #6 now. I see no reason to rev it that hard before shutdown.
If you did this on an RX3 or 4 you would get a backfire that would blow the exhaust system apart.
If you did this on an RX3 or 4 you would get a backfire that would blow the exhaust system apart.
10-31-2011, 12:32 PM
#22
A quick browse through the owner's manual will give you Mazda's take on it.
It will also show you that all of the things the mechanic told you are right from the same book.
7k is way too high. 3k is more like it. That said. It's not really necessary at all. I've never flooded.
It will also show you that all of the things the mechanic told you are right from the same book.
7k is way too high. 3k is more like it. That said. It's not really necessary at all. I've never flooded.
10-31-2011, 01:34 PM
#23
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In my experience a quick rev before shutdown can help in some scenarios. In really hot Phoenix temperatures, I've had a few harder starts (I wouldn't call them hard, just 1 or 2 extra cranks) when making several successive short trips, i.e. going to two stores right across the street from each other. Doing a quick rev to ~3000 rpms and shutting down after letting off the pedal seems to mitigate this. Holding it there for a period of time doesn't seem to make any difference. I would NOT recommend going to 7000 rpms, thats way too high for no load.
11-02-2011, 01:32 PM
#24
This was an S1 problem. Intended to prevent flooding from cold shutdowns. No need to do this on an S2.
That said... if you want to be ridiculously cautious for no reason (better change your oil every week, to be on the safe side) then I don't see any downside other than worse gas mileage and bad emissions, or possibly reducing the life of your cat.
That said... if you want to be ridiculously cautious for no reason (better change your oil every week, to be on the safe side) then I don't see any downside other than worse gas mileage and bad emissions, or possibly reducing the life of your cat.
11-07-2011, 01:55 PM
#25
Super Moderator
High revving ANY Rotary before a turning off is a total waste of time and just not necessary.