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Silly question regarding RPM when reving in neutral.

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Old 04-06-2013, 08:31 AM
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Silly question regarding RPM when reving in neutral.

Yet another thread which show how much a greenhorn I am at car mechanics.

I put my food down on my C200 Kompressor whilst in neutral. The rev meter went up to just over 4000rpm, but it isnt even close to the maximum indicated on the dial. Do the Benz's have some sort of safety switch to prevent engine damage?

When I had my V6/V8 Holdens and I put my foot down, I myself had to hold off from the needle going into the red.

Last edited by anonymousmoose; 04-06-2013 at 09:54 PM.
Old 04-06-2013, 09:29 AM
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06 C230 SS 6spd
its the fuel cut off most likely.
Old 04-06-2013, 11:59 AM
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2005 C230K, 2016 Honda CR-V, '74 Lotus Europa
You may already know there is a rev limiter and I suspect that this is an extension of that. It is so easy to over-rev a motor when it's not under load. I might have expected it to cut out at the red line but your experience doesn't really surprise me. I've never tried it on my car. Just never thought about it.
Old 04-06-2013, 12:39 PM
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yeah I noticed the same thing awhile back.. thought my car was broke... glad its not that. =)
Old 04-07-2013, 12:50 AM
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It's a green German thing. Cars in neutral will not rev higher than 4K rpm. Throw the car in second gear and you can redline the car in motion. This is to cut down on polution while stationary. I wonder how the green's feel about Mercedes plans to offer a 3kW generator to run a fridge during a power failure or make power for a remote picnic site. The engine will run all night.

Mercedes does not cut fuel (except in a wreck) rather just throttles back.
Old 04-07-2013, 05:28 AM
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I drive a Toyota Hybrid...
there is a trick to red higher than 4k in Neutral, put it in drive first, let the car move and roll, then quickly shift it to Neutral, then step on the gas u get the epic 4 bangers engine revving
Old 04-07-2013, 04:12 PM
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12 BMW 535Xi; Retired 02 C230 Sport Coupe
I've tried this on several of my retired cars.
Its like the fuel is on , then off, then on again, repeat. The RPM needle seems to bounce over and over. But it is solely to protect the engine with no load on it. No damage to the engine since it can't over-rev.
Old 04-08-2013, 12:15 AM
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2012 C63 P31, 2013 E63 P30
Most new cars work this way. My SRT cars won't rev high in neutral. I don't think you can get full power in reverse either.
Old 04-08-2013, 04:37 AM
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late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
Normal! ECU regulated. 4K peak.
Old 04-08-2013, 10:58 AM
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That was the one thing I hated in my C55. The C350 6MT didnt have that problem .
Old 04-18-2013, 03:33 AM
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Thanks for the feedback everyone.

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