Hey guys I have a question about redlining my rx8. I've heard 100 times that in order to keep my car healthy I need to redline once a day. Why is that? I understand that it prevents carbon buildup but can someone explain the science behind it. I've tried searching for the answer but I can't find the answer.

Thanks

 

It's to burn off carbon. High load and high RPM means you are moving lots of air, fuel, and heat through the engine. This helps to not only burn off carbon, but it's a bit harder for any newly forming carbon to settle on the surfaces before it is blown out of the engine.

It's been experienced over and over that after a hard day at the track the engine simply runs smoother, more responsive, etc... It was also very common that automatics (which tend to run lower RPMs on average) were having severely carbon choked internals.

Don't make it so specific about frequency though. We are mostly just trying to get owners to not be afraid of high RPM and really leverage it. It's one of the funnest parts about a rotary, so just enjoy it regularly and it will become second nature.

 

Does redlining while I'm parked in neutral have this same effect or do i have to in gear?

 

kind of pointless in neutral as the theory behind the 'redline a day' is to maintain a high rev for a period of time to break up deposits. For example, a nice 2nd or 3rd gear redline pull.

Just free revving in neutral is no different than doing a fast sprint from your couch to the bathroom as a form of exercise lol...

 

You are only moving around 20-30g/s of airflow through the engine redlining in neutral, and this is assuming you jab the throttle hard. If you slowly get there, or just hold it up there, you are moving even less than that. By comparison, at redline at full throttle is more around 190-200g/s of airflow.

No, it needs to be in gear. 1st and 2nd gear can redline at full throttle in most places in the US without breaking the speed limit (40mph and 63mph respectively). 3rd gear is usually easily done, though less legally (93mph). 4th gear isn't really recommended because you are pretty much reckless at that point in the eyes of just about any cop out there (~120mph). 5th gear is even more so (~140mph). If you can hit redline in 6th gear and not on a dyno, congratulations! (it's 168mph, far past our aero limits) (These are series 1 gearing speeds)

Seriouslly. If you haven't done it yet, go have some fun...

 

+1^ naze!
Fun, fun, fun!
To me it's the best part of having an RX8.
The sound of the rotary at WOT is sweet.

 

Another reason to get into the upper rev range is to open all of the exhaust/intake ports. Both the 4 port and 6 port engines have shutter valves that open at certain RPMs. Not getting into the upper rev range can cause carbon to build up on these valves, causing them to stick.

This is my understanding at least....someone please correct me if I stated something incorrectly.

 

Not trying to hi jack forgive me if I did so. But are there any consequences for redlining my 4 port 50% of the time I drive it? I usually do first gear redlines to about 45 mph.I know redlining cleans carbon but I'm afraid my driving habits may be to extreme for it and could possibly decrease my engines life rather than increasing it.

 

Taken to an extreme, yes.

You want the high load high heat high airflow of full throttle high RPM, it's healthy. However the flip side of this is that it is still high heat, and that heat has to go somewhere. Over-taxing your cooling system has it's own problems, and at the extreme range, the side seal springs can only take so much heat before they start to warp. 100% race motors see side seal failures as a result of this before they see failures from any other component.

So in a way, yes, driving it excessively hard is shortening the life of the engine a bit, but trust me, 50% hard on the street is less than half of the heat and wear of 100% on the track. Plus, you have an automatic and a lower redline, so you aren't even at the high RPM point of most of the life of race motors. I wouldn't worry about it if I were in your shoes. Just make sure you aren't cooking off your transmission fluid, you do oil changes regularly, and monitor coolant temps and cooling system efficiency and you will be fine.

 

So you are saying that half of the time when you accelerate in first gear, you redline it? This is pretty extreme, and isn't required to keep the engine free from carbon buildup.

I usually try to do at least one or two redline pulls everytime I drive it, but this is no where near 50%. Also make sure to only go into the upper rev range once the oil is up to temperature....and remember that the oil will get up to operating temperature AFTER the coolant gets to operating temperature.

 

There were a couple of posts by one of the more knowledgable members here that going all the way to the beep is hard on the tip seals. So I wind it up under load. High enough to open all the ports, as JCrane82 points out, but not all the way to 9K.

A long twisty highway on-ramp is a great place to do this.

Ken

 

I have not heard the warning about the beep. Do you remember the thread?

 

Not one specific thread. The race teams found that the rotor tips could start contacting the housing around 9,000rpm and there is a subset of members that take this to heart.

My personal opinion on it is that it isn't an issue for the street RX-8s. True, rotating assembly balance probably matters a bunch here and you don't know how well your engine is balanced, but the OEM tach is also optimistic. At 9,000 indicated you are below 9,000 actual. I'm sure the race teams were using actual. The beep also starts around 8,000 actual? which is acknowledged as under the threshhold of the perceived danger point.

Teardowns of street engines hasn't shown a problem here, even engines that were driven quite hard up to the beep.

If you want to play it safe and shift at 8,000 indicated, that's fine too, no harm done of course, still plenty high enough for the purpose of carbon mitigation.

 

Thanks RIWWP.
I actually listen for it when I don't want to take my eyes off the road. I thought it was OK to do so.
If this is an issue, I may have to start watching the tach instead.

 

That is just my opinon. Plenty of people disagree, so you may want to listen to other opinions.

 

I hardly ever hear the beep in my car. I listen for the exhaust tone and a mildly aggressive muffler system aids in that.

 

Oh yes, I always value other opinions, even if I don't agree with them.
I tried searching, but came up empty.
I'll look some more later.
Thanks.

 

I don't always run it up to the beep, I'll listen to the engine a lot, there's a long straightaway right before I get to work where I like to be sure I get at least one good redline in, and sometimes there's cars around, so I'll listen for it then.
I'm sure the more I drive it, I'll know when to shift right before it comes on.

 

okay so i redlined my car today, and i mean i really let the revs bounce. immediately after i realized a very noticeable power loss and the car does not sound how it normally would, didnt even think id make it home and i was around the block. Car stays at idle but it sounds very off. Think i might have blown an apex. somebody please help.

 

Does it seem like it's trying to play catch up with itself?

 

when slowing down the revs kinda jump if thats what you mean.
Took it to a mechanic and the guy said that "two of the cylinders arnt working." guess that means one of the rotors is busted which means i probably chipped a seal. Guess i gotta take it to somebody who knows that theyre doing.

 

Yes, you can't trust a mechanic that doesn't actually know the rotary engine. Plenty think they do and write off every single problem as "a blown engine" just because they don't actually understand what they are dealing with.

 

First off find a new mechanic this engine has no cylinders and if a mechanic refers to a rotor face as a cylinder he don't know what he's talking about. The only way to see if a rotor has failing seals is a compression test that will tell you if any are failing.

 

Get a compression test and post the results here from someone who can test compression on a rotary motor (most likely a mazda dealer unless you are lucky enough to have a forum member or rotary shop with the proper tester nearby). If you go to a dealer expect to pay between $150 and $250. How many miles do you have? What year is the car? Have you changed the coils recently/ever? If the compression test is fine it is probably the coils, but post the answer to these questions and we can help you on your next step.

 

i have a 2004 rx8 with 104k miles,i did not get a compression test yet, taking it to a rotary mechanic this week. not sure when the plugs have been chnged but the coils were changed maybe 500 miles ago because one of the coils was cracked. When i drive the car it feels very very weel, the car just doesnt want to accelerate and it seems to hessitate when i try to get the revs past 4-5k rpms. The sound is almost not there and sounds very airy compared to usual. I have a megan racing catback, not sure when it was put on because i bought the car used not very long ago. Due to looking in the forums it seems to maybe be clogged catback but i dont think that could be something to suddenly happen within seconds. Do you think that could be it?