Many of you will be aware of the fact that most powerful German saloon cars are electronically limited to 155mph. My understanding is that there is some kind of gentlemans agreement between the big German car firms to electronically limit their most powerful models in order to have half a chance of maintaining de-restricted autobahns. Can anyone verify this?
Interestingly, in recent years, more and more cars from Merc, BMW and Audi's ranges have been qualifying for this restricion. It is remarkable that some mid-range diesels are now capable of these speeds with plenty of low-down poke too, it does beg the question - why do people bother with the vastly more expensive top-end performance models anymore?
Regarding the removal of these limiters, is it something that Joe Q. Public can have done or does one have to be a company insider or racing driver to unlock the hidden bounty? With some of the most powerful saloons reportedly capable of 200+mph (M5, RS6 et al), are these cars actually engineered to cope with these speeds. I mean, in terms of brakes and suspension etc, a car that can do 200mph will need much more heavy-duty kit than one that will do 155mph. Do manufacturers actually design these cars with 200mph in mind and then fit a limiter?
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It also means that W or Y rated tyres are fine, whereas if the car's true top speed (190+mph) was available, then hyper expensive rubber would be required as standard fit.
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My 330d is 'limited' to 155mph, I suspect it can't really go an awful lot faster but it is limited nonetheless. I have seen a number of the chip/tuning companies offering 'power hike plus de-restrict' so I have hitherto assumed that the limit is a function of ECU programming, probably something like the rev limiter ?
Anyhow, IIRC the maximum legal speed limit is 70mph on this island so I doubt I'll ever find the imposed restraint of a 155mph limit to be too frustrating.
It does beg the question as to why buy more powerful variants, especially when the in gear performance of higher powered diesel models from BMW and Audi is so similar, my only answer would be 'because you can' ?
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My M3 was limited to 250km/h (155mph). BMW will remove the speed limiter if you are in possession of a racing driver's licence, though I don't have anything like that. I drove it a number of times on the autobahn flat out, an indicated 275km/h, but this speed requires considerably more concentration than 200km/h and the fuel consumption is obviously pretty horrendous.
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I've seen postings around the net that imply if one has passed the BMW driver training course a factory ordered car can be de-restricted.
Can't find any solid evidence, but I didn't look too hard.
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Yes, Hector, my recollection is that it was a gentlemens agreement between the big German car manufacturers.
It is of course ridiculous to have so many everyday cars that will now go that fast - I wonder how many drivers check their tyres, fluid levels, etc. before blasting down the autobahns at that speed?
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I remember reading (many years ago in WhatCar I think) that 155mph equates to 248kmh, which is just below the "physcological" 250kmh. Think it was a nod to the German "green" parties years ago.
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I'd much rather buy a car that had fantastic looks, was limited to say 120mph but had fantastic in-gear acceleration which would be much more useful on our crowded roads for safe overtaking.
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was limited to say 120mph
Like the Japanese do, you mean? :-)
Ok, ok, their limiters are set at 112mph but the rest of it applies.
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I was more under the impression that several components would need beefing up to cope with 180-200mph speeds (firmer suspension, stronger tyres and of course more powerful brakes) over 155mph speeds, with a corresponding increase in weight and decrease in tactility. As even the fastest autobahn driver spends less than 1% of the time at speeds of over 150mph the balance between outright top speed and day-to-day economy and practicality has to be drawn somewhere - much as the balance between journey times and fuel economy has led to 56mph limiters on large vehicles.
Edited by Dave_TD {P} on 23/12/2009 at 13:15
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