Besides the warning buzzer, I was wondering what happens if you were to push the engine over redline. A friend of mine missed a gear while racing his 300GT, the engine went over redline and the engine died. Does Mazda have any other safety precautions other than the warning horn (which could be a tad bit louder)?

The fuel cuts out and you start coasting.

Yes, the engine cuts out at 9500 RPM

...thanks for the info

It should be noted that the rev limiter (I think it's actually at 9250rpm) will not help in the case of an accidental downshift. It will prevent you from using the gas to rev it over redline, but there's no protection against shifting into 2nd at 100mph and blowing the engine.

hey i redlined the car in the garage to show my friend but later when i took it out i saw fresh oil on the floor,what does that mean?

it means your car is ruined

congrats, you killed the car. you win the "i'm an idiot" award.

Originally posted by RX8Lover
congrats, you killed the car. you win the "i'm an idiot" award.

:eek: agreed!

Originally posted by Dookie_Rx-8
hey i redlined the car in the garage to show my friend but later when i took it out i saw fresh oil on the floor,what does that mean?

You're joking, I hope?

Originally posted by Dookie_Rx-8
hey i redlined the car in the garage to show my friend but later when i took it out i saw fresh oil on the floor,what does that mean? It means either you have a leak somewhere, or you missed the filler when you were topping up the oil. :p A rotary has no conrods, so it cannot punch a hole in the block as a reciprocating engine can. The consequences of overreving a rotary are internal damage with no external symptoms except for it running like crap (if at all).

Seriously, if the engine is at normal operating temperature there's no harm in redlining it under no load - I'm not sure why folks are calling you names for doing it. Now if the engine was bone cold, then yes, you're a fool to redline it under any conditions, let alone under no load in the garage.

Originally posted by eccles
Now if the engine was bone cold, then yes, you're a fool to redline it under any conditions, let alone under no load in the garage.

...it won't let you get higher than 6k or something, i thought.

What happens after redline??? you enter the TWILIGHT ZONE! or was it TIME TRAVEL ? j/k

You get the nasty fuel cut-off...I hit it once, will never again. Worst feeling ever.

hmm.......it was a nice day that day though so iunno

Originally posted by RX8-TX
What happens after redline??? you enter the TWILIGHT ZONE! or was it TIME TRAVEL ? j/kDon't forget about the flux capacitor engaging.

Originally posted by RX8-TX
You get the nasty fuel cut-off...I hit it once, will never again. Worst feeling ever.

Agreed. You go from being pushed back in your seat to being thrown forward with the same force. Only did it once!

Well, I think eccles had the best advise. When I was having some motor work done to my FD some years back I asked the guy about over reving, because I thought rotarys could rev up in the range of 12000. Now maybe not ours, and that's why I asks. He basically told me that I would be pretty safe up to about 1100 then I would start see some problems. He also told me, that at least my motor starts to see a decrease in power in the 7500 - 8000 range. The stock turbos just aren't efficient in that range. I've had the buzzer come on several times with out worry, and have never seen any problems. I would think with the newr technology you'd be just as safe. I'm willing to bet 9k was safe all along, and they moved it up to market it like the S2000. But like eccles said don't go and start it up and rev the sh!t out of it cold.

That sucks about the whiplash fuel cut off. Is the 8 speed limited too? Has anyone ran it up to speed. I remember my GMC truck was speed limited to like 85mph. That sh!t was embarrassing when it would shut down.

Over-revving a rotary (like on a 2nd gear misshift) isn't a big deal at all. Typically when that happens, you instantly realize that you're in the wrong gear and get out of it. The engine isn't under load or anything, and there likely wouldn't be fuel or spark at that RPM.

Over-revving a piston engine is all kind of bad news - things can hit and break. That's part of the beauty of a rotary - it just doesn't care. If you over-rev it, say "oh well" and don't do it again. No long or short term damage. Not a good idea to do for fun or anything, but if it does happen by accident, you won't turn the motor into a paperweight.

Dale

Originally posted by dcfc3s
Over-revving a rotary (like on a 2nd gear misshift) isn't a big deal at all. Typically when that happens, you instantly realize that you're in the wrong gear and get out of it. The engine isn't under load or anything, and there likely wouldn't be fuel or spark at that RPM.

Over-revving a piston engine is all kind of bad news - things can hit and break. That's part of the beauty of a rotary - it just doesn't care. If you over-rev it, say "oh well" and don't do it again. No long or short term damage. Not a good idea to do for fun or anything, but if it does happen by accident, you won't turn the motor into a paperweight.

Dale While it's true that a slight overrev won't hurt, it's quite false to say that you cannot hurt a rotary through overreving. Despite the fact that nothing's reciprocating in there, there are still loads on the eccentric shaft, and if you massively overrev, the shaft can and will flex to the point that the apexes of the actual rotors - not just the apex seals - contact the rotor housings. Once they've done that once, the damage is terminal - if it's slight, it may not manifest itself immediately, but if it's major, you'll start running on one lung right then and there.

DO NOT REDLINE YOUR ENGINE TO FUEL CUTOFF!

Here is why:

YOu have your engine at 9500rpm, when suddenly the fuel stops flowing.

You are now running ( briefly) a VERY lean fuel / air mixture.
You are almost guaranteed engine knock if you hold on the throttle doing this.

Then you will possibly need a new set of apex seals, as in a new engine.

This is the singular, most idiotic thing that Mazda could do.

They *should have* regulated this with ignition cutoff.
Then the worst that could happen is a set of fouled spark plugs.

Originally posted by canzoomer
DO NOT REDLINE YOUR ENGINE TO FUEL CUTOFF!

Here is why:

YOu have your engine at 9500rpm, when suddenly the fuel stops flowing.

You are now running ( briefly) a VERY lean fuel / air mixture.
You are almost guaranteed engine knock if you hold on the throttle doing this.

Then you will possibly need a new set of apex seals, as in a new engine.

This is the singular, most idiotic thing that Mazda could do.

They *should have* regulated this with ignition cutoff.
Then the worst that could happen is a set of fouled spark plugs.

The fuel does not cutoff. To those that have not yet hit the fuel cutoff, Mazda should not have called this a cutoff. The fuel flow does not stop! It just does not increase! You maintain power. They could not have regulated this with an ignition cutoff. Again I think the misconceptions are due to the wording in the manual. What happens is you stop accelerating. You maintain the speed at which the cutoff occurred. In other words, your going 50 in second with WOT, speeds increasing, 51..52...58..(hear buzzer)..60...64..(hit fuel cutoff)...64..64..64. You are "thrown" forward but it's not because of any decelaration, it's because you don't lift off the gas pedal and do not expect to stop accelerating. All you experience is a lack of acceleration which is disconcerting because you're not expecting it. When you back off the pedal your body is expecting the lack of acceleration and you don't fly forward because your expecting it. That is why you fly forward when the cutoff is hit--you're not expecting the sudden change in acceleration.

yea, a lot of people say "cut-off" as a term of NO fuel, that is obviously not true. "cut-off" as red-rx8 said, is when additional fuel to the fuel-air mixture is stopped not, no fuel at all, that would be bad.

I hit 10000 RPM racing and nothing happened. It just feels like thats the end of your engine making more power, so you shift up... simple as that.

my idiot brother was "racing" a celica gts that wasn't even his, and he ruined the engine by downshifting from 5th to 1st at about 60mph (seriously). Haha, just thought I'd share that with you guys!

why would he do that? wut kind of stupidity is that??

Originally posted by eccles
While it's true that a slight overrev won't hurt, it's quite false to say that you cannot hurt a rotary through overreving. Despite the fact that nothing's reciprocating in there, there are still loads on the eccentric shaft, and if you massively overrev, the shaft can and will flex to the point that the apexes of the actual rotors - not just the apex seals - contact the rotor housings. Once they've done that once, the damage is terminal - if it's slight, it may not manifest itself immediately, but if it's major, you'll start running on one lung right then and there.

From what I am told the biggest risk is in breaking the driveshaft.

The drag engines being rebuilt by a couple of people and that got to 14,000 have had a centre crankshaft bearing added to reduce flex loads.

I have seen an example of a cracked RX-7 3rd Gen turbo broken shaft. Not pretty.

Originally posted by red_rx8_red_int
The fuel does not cutoff. To those that have not yet hit the fuel cutoff, Mazda should not have called this a cutoff. The fuel flow does not stop! It just does not increase! You maintain power. They could not have regulated this with an ignition cutoff.


Thaks for that correction.
I did not know this, and never checked.

I simply avoid redlining it to that point.
There is no reason to. This engine makes max horsepower at 8,500rpm, and falls off quickly after that point.

When you hear the buzzer it is time to shift.

Originally posted by canzoomer
I simply avoid redlining it to that point.
There is no reason to. This engine makes max horsepower at 8,500rpm, and falls off quickly after that point.

When you hear the buzzer it is time to shift. Not quite true. While it's true that the HP tails off after 8500, it's also true that there is always more torque available at the wheels (and thus more acceleration available) all the way to the redline in each gear than at the same speed in the next higher gear. See this post (http://www.rx8club.com/showthread.php?s=&postid=96246&highlight=cascades#post96246) for more detail.

Originally posted by eccles
Not quite true. While it's true that the HP tails off after 8500, it's also true that there is always more torque available at the wheels (and thus more acceleration available) all the way to the redline in each gear than at the same speed in the next higher gear. See this post (http://www.rx8club.com/showthread.php?s=&postid=96246&highlight=cascades#post96246) for more detail.
If you say so!

While I am NOT the definitive drag racer, I ran some 1/4's on my RX-8.
This was during tuning tests on our fuel/air/ignition controller.

I got best time with shift point at under 9,000 than over.

Best time with fuel/air only, up 25HP was a 14.68
Best time stock was 14.93
Best time with fuel/air/advance, around 50HP up was a 14.36
When I tried running the last one with higher shift points I got about a 1/10th less performance.

For those who say my 1/4's suck, yeah, you are right, no 8K drops, and the reflexes of a 47 year old (me).

I am also at around 3,000 feet altitude.

But Hey, it could be my driving, I admit that.

Originally posted by canzoomer
If you say so!

While I am NOT the definitive drag racer, I ran some 1/4's on my RX-8.
This was during tuning tests on our fuel/air/ignition controller.

I got best time with shift point at under 9,000 than over.

Best time with fuel/air only, up 25HP was a 14.68
Best time stock was 14.93
Best time with fuel/air/advance, around 50HP up was a 14.36
When I tried running the last one with higher shift points I got about a 1/10th less performance.

For those who say my 1/4's suck, yeah, you are right, no 8K drops, and the reflexes of a 47 year old (me).

I am also at around 3,000 feet altitude.

But Hey, it could be my driving, I admit that.

Were you using the G-tech?

How did you launch the car?

Cheers,

D-san

Originally posted by Digisan
Were you using the G-tech?

How did you launch the car?

Cheers,

D-san
GTech Pro
6K
Some slip, not crazy amounts.

Originally posted by canzoomer
Best time stock was 14.93

it could be my driving, I admit that.

:D that's really quite a bit better than many who've run stock RX-8's :cool:

good job man. i'm sure it's better than i could do.

Originally posted by wakeech
:D that's really quite a bit better than many who've run stock RX-8's :cool:

good job man. i'm sure it's better than i could do.

He got it over Gtech pro, which is not 100% accurate.

Originally posted by canzoomer
This engine makes max horsepower at 8,500rpm, and falls off quickly after that point.

When you hear the buzzer it is time to shift.

Yes! I use the buzzer for a shift indicator. Sometimes, I'm just not quick enough. 8.5 k to 9.5 k can go very fast when you're concentrating on other things like navigating a merge or deciding if you really can make the light or not.