Manual Transmission
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2017 GLA 250 4Matic
Manual Transmission
Scenario:
If you are in 4th gear and your rpm is say 5500 and you accidentally shifted to 2nd, would there be a mechanism that would prevent you from shifting into a lower gear so that you won't kill your engine?
If you are in 4th gear and your rpm is say 5500 and you accidentally shifted to 2nd, would there be a mechanism that would prevent you from shifting into a lower gear so that you won't kill your engine?
#2
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Re: Manual Transmission
Originally posted by Big Sheesh
Scenario:
If you are in 4th gear and your rpm is say 5500 and you accidentally shifted to 2nd, would there be a mechanism that would prevent you from shifting into a lower gear so that you won't kill your engine?
Scenario:
If you are in 4th gear and your rpm is say 5500 and you accidentally shifted to 2nd, would there be a mechanism that would prevent you from shifting into a lower gear so that you won't kill your engine?
1. Your at a standstill and rev engine
2. You rev much higher then redline
A friend drove my car and downshifted too early...the car slowed down quickly, but the fuel was cut until below redline...in a normal car, he would have blown the engine.
Either way, its not good for the car, don't do it on purpose.
Erik
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2017 GLA 250 4Matic
I mean is there a mechanism that will not allow you to downshift? Something like a lock that prevents you from shifting the shifter down until the computer senses the it won't over rev the engine.
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C230 Sport Coupe
No, there's nothing like that except of course for the lockout preventing you from putting it in reverse when you're going forward. That's why we enthusiasts love manuals - if they were idiot proof there would be no fun! Besides, like tifosiv122 said, why would you need one as long as you've got your rev-limiter? Both the '02 and '03 models have them (as do almost all cars with a manual gearbox these days).
#5
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Yes, there is a mechanism of some sort....I dont think you can shift into 1st over a certain speed...or its really hard to the point where you would really have to force it into gear.
I suppose it would be useful if the electric device failed, having a mechanical backup, but I don't know of any such system.
Erik
I suppose it would be useful if the electric device failed, having a mechanical backup, but I don't know of any such system.
Erik
#6
Re: Manual Transmission
Originally posted by Big Sheesh
Scenario:
If you are in 4th gear and your rpm is say 5500 and you accidentally shifted to 2nd, would there be a mechanism that would prevent you from shifting into a lower gear so that you won't kill your engine?
Scenario:
If you are in 4th gear and your rpm is say 5500 and you accidentally shifted to 2nd, would there be a mechanism that would prevent you from shifting into a lower gear so that you won't kill your engine?
A rev limiter is only useful if you forget to shift or if you miss an upshift.
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2002 C230 Coupe(M111)
Re: Re: Manual Transmission
Originally posted by Lynn
There is no such mechanism on any gear. If you do what your scenario suggests, you will over rev the engine. A fuel shut of or ignition based rev limiter won't help. The engine is mechanically connected to the wheels. When you down shift to the wrong gear, the wheels will force the engine to turns the revs that match that gear. There is absolutely nothing on the car that can prevent this and the damage that may result.
A rev limiter is only useful if you forget to shift or if you miss an upshift.
There is no such mechanism on any gear. If you do what your scenario suggests, you will over rev the engine. A fuel shut of or ignition based rev limiter won't help. The engine is mechanically connected to the wheels. When you down shift to the wrong gear, the wheels will force the engine to turns the revs that match that gear. There is absolutely nothing on the car that can prevent this and the damage that may result.
A rev limiter is only useful if you forget to shift or if you miss an upshift.
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2002 C240 6-spd (ret)
Re: Manual Transmission
Originally posted by Big Sheesh
Scenario:
If you are in 4th gear and your rpm is say 5500 and you accidentally shifted to 2nd, would there be a mechanism that would prevent you from shifting into a lower gear so that you won't kill your engine?
Scenario:
If you are in 4th gear and your rpm is say 5500 and you accidentally shifted to 2nd, would there be a mechanism that would prevent you from shifting into a lower gear so that you won't kill your engine?
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2003 C230K Sport Coupe, 1986 190E 2.3
Re: Re: Re: Manual Transmission
Originally posted by Outland
No doubt someone will find a way to blame MB for this 'oversight'.
No doubt someone will find a way to blame MB for this 'oversight'.
If you want to drive stick you need to learn how to push that clutch back down if you need to and do it quickly to not hurt the engine or your car. If you do not know at what speed you can downshift to a certain gear then you need to either not downshift or you need to get an automatic. My wife did not know how to drive stick until 3 weeks ago and she has picked it up quite well. She even downshifts to stop now and she knows what gear she can hit and when she can hit it. And it has only been 3 weeks and she learned on the Benz. It is not rocket science but if you need protection from damaging the engine on a downshift then I am sorry to say that you may have made the wrong transmission choice.
#11
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Im not sure if its the same for the 2.3l '02 engine, but for the 1.8l '03;
Standstill - Fuel Cuts at 4,000 rpms.
While Driving - Fuel Cuts at 6,250 rpms.
Redband is 6,000-7,000rpms.
Erik
Standstill - Fuel Cuts at 4,000 rpms.
While Driving - Fuel Cuts at 6,250 rpms.
Redband is 6,000-7,000rpms.
Erik
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C230 Kompressor SPORTS COUPE
As someone mentioned before I am pretty sure there is a locking mechanism for first gear that does not allow you to down shift into it above a certain speed.
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C230 Sport Coupe
No. You can't get into first when you're moving b/c of the issue of synchronizing with such a small gear when you're moving. It may end up behaving like a lockout feature, but it's not a "feature." Anyone who's ever driven a farm tractor will know what I mean.
#15
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i remember a couple months ago i was with my friend in his celica and he was trying to show me it was fast
and he was floring it but accidently shifted into 1st gear instead of 3rd. Well anyway all i heard was a LOUD noise and i saw the RPM go into 7 or 8k? what ever the highest # on the tach is. Well suprisingly nothing happend to his car.
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#16
Luckily, the Celica and handle 8000-9000 RPM. No such luck in my 1984 Subaru. I want a quick 5-3 down shift to pass, but got 1st instead. Yes, the wheels locked momentarily, but when traction was restored, I peg my tack, so I don't know how fast the engine was spinning. Luckily, it was under warranty and the dealer didn't realized I over-rev'd it, so they replaced the crankcase, and all main bearing.
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2002 C230 Coupe(M111)
Re: Re: Re: Re: Manual Transmission
Originally posted by mctwin2kman
My wife did not know how to drive stick until 3 weeks ago and she has picked it up quite well. She even downshifts to stop now and she knows what gear she can hit and when she can hit it. And it has only been 3 weeks and she learned on the Benz. .
My wife did not know how to drive stick until 3 weeks ago and she has picked it up quite well. She even downshifts to stop now and she knows what gear she can hit and when she can hit it. And it has only been 3 weeks and she learned on the Benz. .
Automatics are pretty boring.