4th to 3rd by mistake at high speed

[The HACK]

A 4th --> 3rd shift at anything above 5,500 RPM is what's called a "money shift."

Because it's going to cost you a lot of money.

No rev limiter is going to save you because at this point, technically, the momentum of the car and wheels are what's driving the RPM, not the fuel or throttle control. Eventhough the RPM meter was pegged at say, 7,500 RPM, your ACTUAL RPM could be as high as 10,000 and the meter only shows 7,500 because, well, that's how high the tach will go.

What typically happens at this RPM differs from engine to engine. Certain engines will force the piston to come in contact with the valves, since the pistons are moving TOO fast for the valves to keep up. This will result in a bent valve and a rebuild of the head of the engine and possibly replacing all the pistons that has come into contact with the valves. When this happens, the car may still appear "normal" and not show any signs of damage for a while, but the bent valve will get worse and worse and soon your car will feel like it's running a few cylinders down or mis-fire like crazy, even though right after the money-shift the car may appear to be fine for a while.

Or you could suffer stress failure of the crank shaft due to the excessive RPM that the engine isn't designed to handle. When THIS happens, it's usually quite spectacular...The crank shaft breaks, allowing the con-rods to punch a hole right through the engine block. At this point, there's nothing you can rebuild except to buy a brand new engine block.

[Autobot]

Originally Posted by The HACK

A 4th --> 3rd shift at anything above 5,500 RPM is what's called a "money shift."

Because it's going to cost you a lot of money.

No rev limiter is going to save you because at this point, technically, the momentum of the car and wheels are what's driving the RPM, not the fuel or throttle control. Eventhough the RPM meter was pegged at say, 7,500 RPM, your ACTUAL RPM could be as high as 10,000 and the meter only shows 7,500 because, well, that's how high the tach will go.

What typically happens at this RPM differs from engine to engine. Certain engines will force the piston to come in contact with the valves, since the pistons are moving TOO fast for the valves to keep up. This will result in a bent valve and a rebuild of the head of the engine and possibly replacing all the pistons that has come into contact with the valves. When this happens, the car may still appear "normal" and not show any signs of damage for a while, but the bent valve will get worse and worse and soon your car will feel like it's running a few cylinders down or mis-fire like crazy, even though right after the money-shift the car may appear to be fine for a while.

Or you could suffer stress failure of the crank shaft due to the excessive RPM that the engine isn't designed to handle. When THIS happens, it's usually quite spectacular...The crank shaft breaks, allowing the con-rods to punch a hole right through the engine block. At this point, there's nothing you can rebuild except to buy a brand new engine block.

I guess all I can do is pray there was no engine damage it still seems to run and sound ok so far.

[coolman]

Originally Posted by Autobot

I guess all I can do is pray there was no engine damage it still seems to run and sound ok so far.

I'm sure you find. what he's talking about doesn't happen that often , and it's usually with highly modded up motors with tighter tolerences.

[GQ4Life]

well i dont know about at 5500rpms.. but 4th gear can take u to the 155mph speed limiter at 6400rpms... so how fast were u going at 5500rpms?

id guess about 134mph

[Autobot]

I was watching the tach not sure how fast but I would guess I was going around 120-130

[Autobot]

Originally Posted by coolman

I'm sure you find. what he's talking about doesn't happen that often , and it's usually with highly modded up motors with tighter tolerences.

I think its OK
Oh btw you have a really cool avatar!