What happens above 9000 RPM, Blown engine? :rev:
10-04-2002, 05:10 PM
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What happens above 9000 RPM, Blown engine? :rev:
Hey S2k engine (VTEC) guru,
That's anyone and everyone who can answer this question.
What happens when I hit above 9000 rpm? Blown engine, head gasket?
Please explain this to me as if I were a 12-year-old. My friend's 12-year-old kid asked me this question as I was picking him up from school one day.
I never took mine above 6000-6500 rpm, it's still fast to me so that's all I did. It has 3,500 miles on it now so, I think it's time to try higer revs, but I don't know what will happen if I shift too late.
I tried to look this up under s2ki's search engine, but there were so many different links about above 6000, 8000, and 9000 rpm and "rev-limiters?" and fuel cutoff. I couldn't follow it (I don't know that much about engines, I just like the look and feel of the S) and I know I won't be able to explain this concept of "blown engine/rev-limiter" to the 12-year-old next time I pick him up from school.
Thanks,
LT
p.s. the p/u after school was/is his b-day gift, he wanted to look cool in the S, and it worked/(s).
That's anyone and everyone who can answer this question.
What happens when I hit above 9000 rpm? Blown engine, head gasket?
Please explain this to me as if I were a 12-year-old. My friend's 12-year-old kid asked me this question as I was picking him up from school one day.
I never took mine above 6000-6500 rpm, it's still fast to me so that's all I did. It has 3,500 miles on it now so, I think it's time to try higer revs, but I don't know what will happen if I shift too late.
I tried to look this up under s2ki's search engine, but there were so many different links about above 6000, 8000, and 9000 rpm and "rev-limiters?" and fuel cutoff. I couldn't follow it (I don't know that much about engines, I just like the look and feel of the S) and I know I won't be able to explain this concept of "blown engine/rev-limiter" to the 12-year-old next time I pick him up from school.
Thanks,
LT
p.s. the p/u after school was/is his b-day gift, he wanted to look cool in the S, and it worked/(s).
10-04-2002, 05:28 PM
#2
It's pretty simple: if you're accelerating, and the revs get up to about 9000 rpm, the car's computer will shut off the fuel flow for an instant, until the revs drop back below 9000. If you keep your foot on the gas, the revs will jump back to 9000+, and the computer will once again shut off the fuel. So, if you stay on the gas, you'll get a 'stutter' from the engine, and the revs will stay a little past 9000. The computer won't let you go further.
If you downshift such that the revs go way past 9000, however, there's nothing the computer can do. In this case, it's the transmission that is pushing the engine past 9000, not the gas flow. In this case, you will probably blow the engine. Not good!
Good enough?
JonasM
By the way, go ahead and rev to 9000 - there are enough miles on the engine - you'll like it!
If you downshift such that the revs go way past 9000, however, there's nothing the computer can do. In this case, it's the transmission that is pushing the engine past 9000, not the gas flow. In this case, you will probably blow the engine. Not good!
Good enough?
JonasM
By the way, go ahead and rev to 9000 - there are enough miles on the engine - you'll like it!
10-04-2002, 09:10 PM
#5
What happens when this motor goes much above 9K rpm? (Fill in or correct what I'm about to write.)
Bottom line: Valve float, piston hits valve, valve puts hole in top of piston, valve breaks.
The strength of the valve spring is designed to be strong enough to lift the valve closed after each time the cam lobe pushes it down into the cylinder, but only if the cam lobe doesn't push it down again before the valve is fully up again.
Ever gone to the fair or carnival and played "Wack-a-Mole"? Imagine there is only one mole and the mole is the valve. There is a spring that pushes the mole back up after you (the cam lobe) wack it down. The mole always comes up the at the same speed after you wack it. But there's a catch - another mole (the piston) is just under the first mole and it goes up and down at more or less the same pace as the mole you're wacking (the two are sorta sitting on "over/under" seats). As long as you keep wacking the mole no sooner than the moment it gets completely out of its hole, the mole underneath is fine 'cause it "ducks" back down just in time. If you wack it slower (less than "redline"), no problem there, either. Now, let's say you decide to speed things up and start wacking the mole faster (like before it completely comes out of its hole - same as going over "redline"). You'll wack that mole down into the second mole before it has a chance to "duck" back down. You will now have either a mole with a sore head or a mole with a sore ass or both.
How can you make it safe to wack the mole faster and more frequent? Give the first mole a stronger spring so it can pop back up sooner.
And this was my "12 year old" explanation.
Bottom line: Valve float, piston hits valve, valve puts hole in top of piston, valve breaks.
The strength of the valve spring is designed to be strong enough to lift the valve closed after each time the cam lobe pushes it down into the cylinder, but only if the cam lobe doesn't push it down again before the valve is fully up again.
Ever gone to the fair or carnival and played "Wack-a-Mole"? Imagine there is only one mole and the mole is the valve. There is a spring that pushes the mole back up after you (the cam lobe) wack it down. The mole always comes up the at the same speed after you wack it. But there's a catch - another mole (the piston) is just under the first mole and it goes up and down at more or less the same pace as the mole you're wacking (the two are sorta sitting on "over/under" seats). As long as you keep wacking the mole no sooner than the moment it gets completely out of its hole, the mole underneath is fine 'cause it "ducks" back down just in time. If you wack it slower (less than "redline"), no problem there, either. Now, let's say you decide to speed things up and start wacking the mole faster (like before it completely comes out of its hole - same as going over "redline"). You'll wack that mole down into the second mole before it has a chance to "duck" back down. You will now have either a mole with a sore head or a mole with a sore ass or both.
How can you make it safe to wack the mole faster and more frequent? Give the first mole a stronger spring so it can pop back up sooner.
And this was my "12 year old" explanation.
10-04-2002, 09:42 PM
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Is it true that the motor can actually sustain a 10k rpm redline, and will fail above 10,700 rpm?
I remember hearing these numbers somewhere, can anyone verify?
I'd believe that the 10k redline is accurate, and Honda just lowered it to 9k to avoid excessive warranty claims. . .
I remember hearing these numbers somewhere, can anyone verify?
I'd believe that the 10k redline is accurate, and Honda just lowered it to 9k to avoid excessive warranty claims. . .
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10-05-2002, 06:17 PM
#8
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Originally posted by S2kRob
Is it true that the motor can actually sustain a 10k rpm redline, and will fail above 10,700 rpm?
I remember hearing these numbers somewhere, can anyone verify?
I'd believe that the 10k redline is accurate, and Honda just lowered it to 9k to avoid excessive warranty claims. . .
Is it true that the motor can actually sustain a 10k rpm redline, and will fail above 10,700 rpm?
I remember hearing these numbers somewhere, can anyone verify?
I'd believe that the 10k redline is accurate, and Honda just lowered it to 9k to avoid excessive warranty claims. . .
From what I have heard that is true. Mechanically the F20C can sustain engine speeds up to 10k rpms.
Honda did lower the rev limit to add some margin of safety. Also, currently the cam used in the S2k is only good up to 9k...no more power is made up there anyways....
Id say change to a cam tuned to 10krpm, and tune the ECU also....
10-05-2002, 07:05 PM
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Thanks guys/folks,
You guys are awesome. The kid thinks it's the funniest thing ever (about the mole and the holes), he's still laughing.
I just put on some body kit today, so I will hit at least 8000 rpm tomorrow. If something goes wrong, I'll post it. If not, I'll be toooooo busy having fun driving the S.
Thanks again,
LT
You guys are awesome. The kid thinks it's the funniest thing ever (about the mole and the holes), he's still laughing.
I just put on some body kit today, so I will hit at least 8000 rpm tomorrow. If something goes wrong, I'll post it. If not, I'll be toooooo busy having fun driving the S.
Thanks again,
LT
