What again is the 'magic' rpm range I have to get up to in order for those other 2 ports to open in an AUTOMATIC rx8 please and thank you?

And want excatly makes it so magical that by having 4 ports open at a given time that more carbon build up is removed from the engine then if just 2 ports are open?

I will go search but at times I think doing a search is like drinking...once you have been doing it for a bit in a day you can still talk but the data flow gets a bit fuzzy.

 

in the mt, the secondary ports open at 3750.

its quite possible its the same in the at.

more air flow, more power, more heat, more of everything.

 

if that is correct for the auto then 3750 is a piece of cake to stay at or above. it is just starting to feel alive (or to say waking up) once it goes above 3 rpm. So if this 3750 is the correct figure for an auto then why the fuss about touching red line? Won't having 4 ports open do the same thing?

I'm guessing owners just don't know these figures like we would want to thus a 'general rule' has been created to tell owners that as long as they red line it once each ride all is good. Instead maybe the rule should be 'as long as you stay above 3750 for much of your driving the carbon won't be a problem later on down the road.

thanks for the info

 

All of the fuss about touching red line is more for manuals than autos. The last set of ports open up at something like 7500 RPMS or something ungodly high like that.

 

The advice to hit redline is a little misleading - revs by themselves are virtually useless. Why would doubling the rpm have any effect on carbon buildup?

What is needed is full engine power/wide open throttle.

Max power and highest exhaust gas temps, along with maximum revs WILL clean out the gunk, hence the old rotary saying "drive it like you stole it" - something auto owners apparently rarely do......

S

 

Isnt it kind of hard to maintain high revs in an auto anyway?

 

whats needed is WOT - wide open throttle. for that, all you have to do is put the pedal all the way to the metal. you can have WOT at 3k rpm, granted, its only going to pass 3k rpm very quickly, but its there. you can have WOT from a standstill. usually thats called drag racing.

and i seriously doubt the secondary ports open at 7500rpm in either tranny model. why would it any different from the 3750 from the mt?

 

That's why you should get a little envelope when buy one.

Open it up and it's a free session for HPDE at your nearest track.

 

hah! that would be awesome! too much liability on mazdas end though.

enter on ramps to highways at low speeds (20ish) and punch it around the turn. :D or just enter highways at lowspeeds and punch it to merge into traffic. either way, you'll get wot for a bit.

i commute to school, and for some reason there is always a large section of highway at one particular point that is wide open in the left lane 99% of the time. its straight too. so all i do is slow down a good amount, and have a few seconds of wot to get back to speed. people may think im crazy, but this is engine maintenance.

 

4 PORT
Secondary port opens at 3750RPM
Variable intake valve opens at 5750RPM

6 PORT
Secondary port opens at 3750RPM
Auxiliary port opens at 6250RPM
Variable intake valve opens at 7250RPM

 

According to this article, on page 7, the Secondary Port opens at 3750 RPM and the Auxiliary Port opens at 6000 RPM. At 5500 all you get is more air flow into the airbox and at 7250 you get increased power output because of optimized air flow. *shrug* Red Line or Bust!

 

^Ahh yes. Thank you for clearing that bit if info up for all of us that always state; "A redline a day keeps the Car Dc. away!". Its not just a redline its a floor it! redline guys

No. But if you keep driving like that your car will get hot and over heat (Had a 4 port AT).

 

 

I usually hold around 8500 rpms in second gear for about 10 seconds every other day. I usually hit redline daily but thats just driving normally :p

 

10 seconds? Why would you do that? If your hitting redline daily through "normal" driving, I don't think you have to go out of your way to work the engine any more then that.

10 seconds is a long time to hold an engine at 8500 rpm for no good reason - you're just contributing to wear and tear at that point. Just keeping the engine spun up does not by itself get rid of carbon - you need throttle as well. If your holding at a given rpm for 10 seconds, your not anywhere close to WOT.

Just drive the car like you are sans the "10 second @ 8500" and don't give carbon another thought. It's the granny drivers that need to do worry about making sure they give 'er once and a while.

 

By holding at 8500 he is creating heat and is maintaining as close to WOT as possible. Would you prefer he bounce off the rev limiter over and over again?

 

Not so sure I'm glad I asked...
thinking/guessing my 07 is a 6 port and maybe 04/05 autos (were 4 ports). Not a clue what 'secondary port opens' and 'auxilary port opens' means. What an rx8 always has 2 of it's 6 ports open all the time then at 3750 two more open???

I will check to see what those in the know post to resolve the puzzle for me. Meantime I just think I will let her run through the rmp range above 3k and float around 5k and be happy with that for a bit. Hard to believe that owners must do a redline or have engine problems down the road but what the heck do I know with only 1k on her and only owned an rx7 1980 so long ago I forgot much about it...though was a very nice color gold, that I do remember.

 

I remain puzzled by all this stuff about port opening and carbon. Isn't it true that the devices that control port opening are way up-stream from the actual port in the combustion chamber? In other words, the "port opening" actually takes place somewhere in the induction manifolds, not right at the combustion chamber port. Right? And if that's true, how could those devices collect any carbon?

1.3L

 

Just a redline and then shifting isn't going to keep the ports open long enough or create enough heat to break awat and blow any carbon out. At 8499 rpm I'm not even in striped red so I don't think its hurting anything

 

4 ports and 6 ports engine all have 2 ports opened at all times. But at 3750RPM everyone has 2 additionnal ports that open. For the 4 ports engine well, that's 4 ports opened, end of story. For 6 ports however, you've still got 2 more ports to go (called auxiliary ports) that open later on.

 

Wrong. If you are holding at a rpm range for any given amount of time, you are not even close to WOT. To maintain RPM you can't keep giving it gas or you will increase RPM and speed. Short bursts of acceleration at least make sense; hopefully you can figure out a way to not bounce off the rev limiter - think hard now and give it some time.

 

My point is with your driving style you don't have excessive buildup in the first place. You don't need to do it. My point is also that no matter how you drive, 8500 for 10 seconds every other day is an extremely excessive practice. Plus maintaining rpm/speed means less throttle as you are not trying to increase speed.

Of course this is you car and you should do whatever you feel is right; but others reading this forum shouldn't be under the impression that this is a necessary practice for maintenance - far from it. It's not necessarily that your hurting something - but you are almost definitely applying unneeded strain to your car.

 

If anything, I'd say redline 2 or 3 times... then you're at WOT, all ports open, high RPM, high heat ect for at least 3 seconds or so (depending on gear) per redline... Generally I just redline through first and second every couple of days, sometimes if I feel like having a bit more fun I'll continue through 3rd. I usually dont go higher than that since I dont really feel like getting a ticket or trying to convince the cop I was doing it to clean the engine.

 

i try to do 30-45 seconds of WOT a day. it puts a smile on my face.

all in the name of engine maintenance of course. if you enter a highway and see it completely empty, just slow down to ridiculously low speeds and then downshift (a few times lol) and floor it till you are a bit above highway speeds. then back off.

im pretty sure my engine is healthy and loves me.

 

That and always drop clutch at 9000 rpm