What happens after redline?
10-22-2003, 05:02 PM
#1
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What happens after redline?
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)?
10-22-2003, 06:54 PM
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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.
agreed!
10-23-2003, 10:37 AM
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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?
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?
10-23-2003, 11:08 AM
#11
Prodigal Wankler
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?
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?
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.
10-23-2003, 12:16 PM
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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.
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.
10-23-2003, 09:31 PM
#13
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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.
You get the nasty fuel cut-off...I hit it once, will never again. Worst feeling ever.
10-24-2003, 01:09 AM
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Originally posted by RX8-TX
What happens after redline??? you enter the TWILIGHT ZONE! or was it TIME TRAVEL ? j/k
What happens after redline??? you enter the TWILIGHT ZONE! or was it TIME TRAVEL ? j/k
10-24-2003, 01:31 AM
#16
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Originally posted by RX8-TX
You get the nasty fuel cut-off...I hit it once, will never again. Worst feeling ever.
You get the nasty fuel cut-off...I hit it once, will never again. Worst feeling ever.
10-24-2003, 08:19 AM
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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 **** 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 **** was embarrassing when it would shut down.
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 **** was embarrassing when it would shut down.
Last edited by rtryrktrx7; 10-24-2003 at 08:23 AM.
10-24-2003, 10:28 AM
#18
RX-7 Guru
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
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
10-24-2003, 10:49 AM
#19
Prodigal Wankler
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
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
10-25-2003, 07:09 PM
#20
Forum Vendor
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.
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.
10-25-2003, 10:23 PM
#21
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.
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.
10-26-2003, 07:07 PM
#22
no pistons!
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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.
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.
10-27-2003, 09:11 PM
#23
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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!
10-27-2003, 11:09 PM
#25
Forum Vendor
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.
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.
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.