Reving up on shutdown
#1
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Reving up on shutdown
Hi Everyone,
First, I am a new member to the forum so "hello everyone", I am happy to be a member and owner of one of the greatest cars ever!!!
My question: The sales guy who sold me my RX-8 said that this technique would be good for the life of the "rotors". He recomeneded that I ""REV"" the engine up to 3 grand and then shut the motor off each time after driving. He stated that this technique is good for the rotors especially when driving short distances.
I wanted to get everyone's opinion of this, do you think there is any truth to this technique?
Thanks!!
RX-8.40
First, I am a new member to the forum so "hello everyone", I am happy to be a member and owner of one of the greatest cars ever!!!
My question: The sales guy who sold me my RX-8 said that this technique would be good for the life of the "rotors". He recomeneded that I ""REV"" the engine up to 3 grand and then shut the motor off each time after driving. He stated that this technique is good for the rotors especially when driving short distances.
I wanted to get everyone's opinion of this, do you think there is any truth to this technique?
Thanks!!
RX-8.40
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What's up topgear8 - thanks for checking out my question and replying with your advice...Thanks for clarifying when and not to do the Rev, I was unsure of the amount of times.
Thanks!!
Thanks!!
#8
Rev to 3 before shutoff. Yes. Neccessary any more... perhaps not.
I've had mine for 4 1/2 years and 100k miles now and I still blip the throttle to 3k before shut off out of habit.
Originally, this was done to basically clear the throat of the beast. Older RX7 rotaries had a habit of flooding if you didn't rev it a little before shut off. This is because of the bowl shape of the rotor housings and the rich start up. If any fuel was not blown out before shut off (like shutting it off cold) it would pool up in the housing. On the next start up more fuel would automatically get sprayed in and might be enough to flood the engine. Once flooded, little could be done short or removing the plugs, cutting the fuel supply, and spinning the engine until the excess fuel was pumped out. Major pain.
Shortly after the RX8 came out, Mazda re-flashed the PCM to cut fuel in successive no start attempts to gaurd against this. They also increased the OPM amount to provide a better seal and higher compression ratio.
Short story (after the long one) it worked. You shouln't have to rev it before shutoff anymore. I have shut mine off cold a few times when I wasn't thinking with no ill effects. Many do still do it out of habit and a little bit of fear.
Welcome to the club
I've had mine for 4 1/2 years and 100k miles now and I still blip the throttle to 3k before shut off out of habit.
Originally, this was done to basically clear the throat of the beast. Older RX7 rotaries had a habit of flooding if you didn't rev it a little before shut off. This is because of the bowl shape of the rotor housings and the rich start up. If any fuel was not blown out before shut off (like shutting it off cold) it would pool up in the housing. On the next start up more fuel would automatically get sprayed in and might be enough to flood the engine. Once flooded, little could be done short or removing the plugs, cutting the fuel supply, and spinning the engine until the excess fuel was pumped out. Major pain.
Shortly after the RX8 came out, Mazda re-flashed the PCM to cut fuel in successive no start attempts to gaurd against this. They also increased the OPM amount to provide a better seal and higher compression ratio.
Short story (after the long one) it worked. You shouln't have to rev it before shutoff anymore. I have shut mine off cold a few times when I wasn't thinking with no ill effects. Many do still do it out of habit and a little bit of fear.
Welcome to the club
#9
Registered
Yikes! This should go into the FAQ...if it's not already.
It's in the Quick Tips reference, under "Short trip driving procedure." If you're going to start the car to move it, but not drive it far enough for it to warm up, the procedure is:
1. Start engine
2. Move vehicle
3. Warm engine for 5-minutes at idle
4. Raise engine speed to 3000 RPM for 10-seconds
5. Return to idle
6. Turn off engine
It's kind of a consequence to the fact that warming an engine by idling is not a good thing: the rev blows out the crud that accumulates during idle.
Ken
It's in the Quick Tips reference, under "Short trip driving procedure." If you're going to start the car to move it, but not drive it far enough for it to warm up, the procedure is:
1. Start engine
2. Move vehicle
3. Warm engine for 5-minutes at idle
4. Raise engine speed to 3000 RPM for 10-seconds
5. Return to idle
6. Turn off engine
It's kind of a consequence to the fact that warming an engine by idling is not a good thing: the rev blows out the crud that accumulates during idle.
Ken
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Interesting stuff!!!
I had thought that it might have something to do with cleaning or blasting out the old so to have a fresh shot for the next restart. Thanks Everyone - for all of the input!
I had thought that it might have something to do with cleaning or blasting out the old so to have a fresh shot for the next restart. Thanks Everyone - for all of the input!
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IMO this is the stupidest thing I have ever heard of. It keeps popping up every 5 years in the rotary world.
This used to be an old wives tale before the days of fuel injected rotaries, and was a compensation for poor compression flooding (on older rotary motors the tended to flood easier).
If you have the latest flash on your PCM the only thing you are doing by reving to 3000 RPM is cranking up the heat in the motor so that you can hot soak the engine and breaking down your oil early.
Unless your car is prone to cold start flooding (usually due to low compression) there is no need to abuse your engine by reving it too 3000 RPM and then shutting down.
Hell, after people recommending this, I suppose the next thing someone will post, will be how 0W10 they used gave them more horsepower and that we should all use it in our motors.
This used to be an old wives tale before the days of fuel injected rotaries, and was a compensation for poor compression flooding (on older rotary motors the tended to flood easier).
If you have the latest flash on your PCM the only thing you are doing by reving to 3000 RPM is cranking up the heat in the motor so that you can hot soak the engine and breaking down your oil early.
Unless your car is prone to cold start flooding (usually due to low compression) there is no need to abuse your engine by reving it too 3000 RPM and then shutting down.
Hell, after people recommending this, I suppose the next thing someone will post, will be how 0W10 they used gave them more horsepower and that we should all use it in our motors.
Last edited by Icemark; 10-05-2008 at 12:57 AM.
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That's cool Icemark - I was wondering if someone would speak on the opposite side of the theory - Do you have anything that documents the info?
Thanks!
Thanks!
#15
Rotary Powered Countryboy
I have done it for some time then i stopped I did notice if it is very cold (in the winter when i lived in PA) it did start better the next morning warming up......i think that is up to u if you really want to or not
#16
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...It keeps popping up every 5 years in the rotary world...
Rev before shutting off goes back to before rotaries. My father used to do that on regular cars back in the 50s. I've been told that there were some types of carburetors where you did have to rev before shutting off, but I think they were obsolete by the 50s. Never found anything concrete on it.
The closest thing to reality I've seen on this is that some reciprocating aircraft engines were shut down by turning the mixture full lean and raising the rpm, letting the fuel starve out, rather than by cutting the ignition. Magnetos were turned off (by turning the grounding switch on) after it stopped.
Ken
Last edited by ken-x8; 10-05-2008 at 02:51 PM.
#17
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It does not help the life of the rotors.
It does help prevent flooding on a cold startup (mainly during the winter)...
If you have the updated starter which turns the motor over much faster it is not as much of an issue.
With the '04 before the starter there were times I wondered if it was going to start.
I did have a service department flood my car once.
If you flood the engine and you are not able to ge it deflooded you may find the rev before shutting down in the winter a minor assurance item. It does tend to start easier the next time you start the car.
If I drive short distances I make sure and rev it up depending on if the car is still cold. 3k for 10sec if the car has not warmed up 4k for 5sec if it has had time to be warmed. The car will not appreciate you kicking it to 4k for 5sec if it has not been warmed up already.
Hope that helps.
It does help prevent flooding on a cold startup (mainly during the winter)...
If you have the updated starter which turns the motor over much faster it is not as much of an issue.
With the '04 before the starter there were times I wondered if it was going to start.
I did have a service department flood my car once.
If you flood the engine and you are not able to ge it deflooded you may find the rev before shutting down in the winter a minor assurance item. It does tend to start easier the next time you start the car.
If I drive short distances I make sure and rev it up depending on if the car is still cold. 3k for 10sec if the car has not warmed up 4k for 5sec if it has had time to be warmed. The car will not appreciate you kicking it to 4k for 5sec if it has not been warmed up already.
Hope that helps.
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I work about half a mile from my home, so my warmup time is longer than it takes to drive to and from work. I am very good about allowing the car time to natually warm up, especially after sitting all night. In my case I would think that a rev during shutdown is only beneficial if it's cold outside, any other time it maight be aunescessary. Are there any other tips you all would recoemend in my situation?
Thanks for all the input!!
Thanks for all the input!!
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