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Okay, this may be a stupid question, if so forgive me :-)

But I've seen it said by a few people (and a certain signature) that the engine itself can support a much higher redline, and that the current redline is more to protect the transmission and other gear. So this raises the question: Is it worthwhile to try and up the redline on these cars by a grand or two? An underdrive pulley would probably protect most of the ancillary equipment, and on the R3 at least, I'd like to hope the manual tranny could withstand a 10 or 15 percent increase in revs.

Anyway, just curious.

Spoolin8

iTrader: (2)

I may be wrong on this so someone correct me if im wrong but i believe the Renesis engine stops producing power just before the stock 9k redline so there would be no point in raising it if you cannot produce power past that.

alnielsen

iTrader: (4)

MazdaManiac's tune for the Cobb AccessPort raises the redline about 200 rpm on the manual transmission cars. I don't know about the auto trans. Other tuning options may also be able to make those changes. You would have to consult the company to see if they have that option.
The stock manual RX8 begins to drop off at about 8500-8700. If you are tuning the car, it is no longer stock.
The rev limit was set to 7500, in the automatics, to protect the torque converter. Mazda felt that it couldn't reliably handle any more than that..

Kane

iTrader: (1)

With leaner AFR's you can run to 9300-9500 or so... and pick up power.

04RX8man

^but leaner always has more of a chance of engine troubles

nycgps

iTrader: (1)

For stock setups, the Max HP will show up at 8500 rpm. they choose 9000 because you need some extra rpm for shifting and it looks nice. but there is no point revving further.

You can get more power by tuning, but at the price of shorter CAT life.

Or you can get more power by redesigning the intake manifold. but hmm. good luck with that.

Kane

iTrader: (1)

Yes, but the factory tune has you in the 10's... so there is some safe room there.

Flashwing

While on my own vehicle, I've found the normal lean mixure range of 12.9 - 13.2 air/fuel is too lean to run at the extreme RPM's such as above 9,000 RPM's. I get detontation frequently despite using good gas. I've had to keep that area richer to prevent this from happening.

Mazda also does this in their own tune. The upper RPM area is normally very rich.

The problem you run into with the higher RPM's is the VE of the motor starts to drop. There's simply not enough time to get a full blast of air into the combustion chamber and as the VE drops so does your power output.

You're going to be making your peak power output around 8,500 to 8,800 RPMs.

I run my rev limiter around 9500 but only for the purpose of not wanting to run into fuel cut. When you hit the limiter the motor pulls fuel, not timing, as other vehicles do. If this were to happen under the right circumstances you could suffer some detonation.

Also, if I'm not mistaken, I've seen information suggesting the ring gear can warp or bend because of the excessive RPMs and possibly cause the rotor to come into contact with the housing. I'm not 100% on that.

JinDesu

iTrader: (2)

I believe Accessport can remove the AT limiter to your standard 9k. A few people have done that and suffered nothing to the transmission. Worse comes worse, AT people can get upgraded torque converters for around one grand.

As far as I know, the stock intake doesn't provide enough air when the engine revs pasts a certain RPM, I assume 11k. I have the Rotary Power book and it provides a formula and explanation that, because the rotary is spinning so fast, it doesn't breathe deep enough to provide power.

Get some FI into it, and maybe you can bring it to a higher RPM and still maintain power. Just remember that your Cat will not survive, and you can expect a shorter engine life.

Banner

So it's definitely not worth trying to up the RPM's. As for the life of the cat, well I don't really care, when the car comes up for smog if I have to replace it, I will. Not a big deal. I definitely have to buy myself the cobb tuner in the near future and MM sounds like the best deal around with the maps he provides.
Debating also doing a catback system, and maybe even a high flow cat, but need to find out what the price versus horsepower pickup would be. As for an FI system, well I'm pretty sure they're not legal here in california, (though oddly enough an FI system doesn't void your engine warranty under cal law I hear - weird) so I don't know if I want to put one on the car.
I really just need to learn more about all of it.

xfukxshytxupx

all i have on my car is intake right now and i redline at 9500 and it produces power all the way until then

Banner

Yes, but the car doesn't produce enough power for me. My friend's wrx produces more and gets better gas mileage! Sort of insult to injury :-) When I first bought the car I was figuring I'd turbo it, then I saw that turbos for this car cost twice of what they cost on other cars - wasn't expecting that. So debating what I want to do to it.

CarAndDriver

Hmm, could have researched the car on here and learned that and saved yourself from being insulted and injured.

The 8 is not the car for 0-60 freaks.

Flashwing

There's a difference between producing power and producing additional power. Put any factory tuned RX8 on a dyno and you'll see the power curve take a dive after about 8,500 RPMs.

The car keeps making power, but it peaks at about 8,500 and it falls from there.

shazy

Isn't the difference between this limiter and and a soft limiter is that the soft limiter pulls the timing and the hard one, the one we have is the fuel cut off thing?

Or am i just talking out of my ***?

Brettus

iTrader: (2)

When you hit the rev limiter the pcm partially closes the throttle to about 23% - log throttle position that is what you will see .....


rotaman on here regularly hits 10,000 rpm in his 8 - it seems to pull really well all the way .

Flashwing

I might also add that normally when I hit fuel cut I end up eating my steering wheel. At least in my car it can be rather violent.

Brettus

iTrader: (2)

really ?
I don't really think you have to worry about detonating when hitting rev cut - I have even done it heaps in my turbo with no ill effects

bse50

The stock PCM can't go past the 10k rpm mark i think...
The engine at those rpm is choked so you should really start with some heavy modifications...
Better go with a turbo instead of seeking high NA outputs for a daily driver. If it is a dedicated track car then you have rules to follow, and a whole different approach is needed!

04RX8man

yeah Kane I know the AFR's are 10's so there def alot to be leaned out...just wanted to make sure that the OP knew that running 16:1 might make more power but the motor might last a day....

Get that AFT to 12.5 or 13 at WOT and would def see a few mores horsies out of that 1.3! haha

laythor

just bring some snacks and stop eating your car

04RX8man

^haha the answer to that ? would be.....uh don't hit fuel cut learn where it is and shift before it.....it's there for a safety measure.....

Banner

Notice that no where in this post have I talked about 0-60 times. If that was what I was interested in, I would have bought the v8 mustang I was also looking at (and had talked them down to almost the same price as the Rx8).

I'd like the car to have about 10 to 15 percent more power than it does, having driven it a bit now. Not a lot, just some. If I was really interested in a lot of power, I'd say the heck with it and buy a turbo.

04RX8man

either way above 8500 rpm's the motor does not produce any MORE power...no sense to stress out the motor/trans with extra rpm's if you're not gainig anything except heat and wear...(bad in a motor/trans)

Razz1

Anyone who removes the rev limter on the RX8 is subject to law suit and jail.

At about 10k the flywheel can come through and kill or cut your legs off.

Remove the rev limit and you are a fool.