topspeed 850csi - The Unofficial BMW M5 Messageboard (m5board.com)

danham · 2nd January 2002, 19:49

whats the topspeed of an unlimited 850csi?

best regards
daniel

mikek · 2nd January 2002, 23:07

I once read that it was between 185 and 190 mph.

Regards

Mike K

MikeC · 3rd January 2002, 00:49

With the speed limiter in place, it's of course 250 kph (155 mph), without it the engine will rev to 6000 rpm (290 kph, 180 mph). That is a realistic speed to achieve under good conditions.

Then there's the possibility to lift the rev limiter to 6400 which will allow a maximum speed of almost 310 kph (193 mph). But as the power curve starts falling off beyond 5300 rpm (250 kph/155 mph) there's no way to pass 6000 rpm on a flat surface. You need a downhill section. But that speed is dangerous for the engine because oil supply isn't guaranteed any more (according to BMW). My personal record is at 305 kph (190 mph).

But the speedometer always runs ahead. At my 300+ run it already pointed into the void. It shows about 300 kph at 6000 rpm in 6th gear.

"How fast does your car go?"
"I don't know, the scale ends at 305 already..."

You can use a little software (~60K) that I wrote to determine the real speed of your car.

But - I must say - that the experience of driving Mach 0.25

wasn't as exhilerating as I thought. I expected to wrestle with physics, but no. The car did that speed in a very determined straight line. Almost disappointingly unspectacular.

Almost

...Mike

JetBoy · 3rd January 2002, 00:56

Hello Mike,

At what rpm does the redline starts in the 850csi ? An ex-owner told me that the rev limit is different for each gear !?

Sorry for the stupid Q. I have never been lucky enough to drive a 850csi

[Complete quote of previous posting removed by moderator (readability)]

Gustav · 3rd January 2002, 01:06

Wow, 290 km7h it's alot for real speed. I was doubting it at first, but then considering the B12 5,7 does over 300 km/h. but the B12 5,0 does "only" 275 km7h or what is it?

MikeC, so your car is deregulated? Where did you do that? Hve surprised alot of cars at those speeds? It's always funny to race a what you suspect is a regulated car that isn't until you passed well over 250 km/h. Not that it happens often though... I thkink I'll never done that actually.

MikeC · 3rd January 2002, 01:38

Well, maybe I should mention that my data is valid only for a chip-tuned CSi of 410hp. Don't know about a stock one without just the speed limiter.

@JetBoy
Redline is 6400 in 1st and 2nd, 6200 in 3rd and 4th and 6000 in 5th and 6th (if the speed limiter doesn't stop you at 5300 in 6th).

@Gustav
My old CSi was chipped, my current one not yet. But the next set of tyres will be capable again of such speeds.
The first chips were crap. Long story. Don't buy at Wetterauer! I am still looking for new chips. Koenig is ridiculously expensive (and unfriendly), Hamann is just expensive. Then there are a lot of others who offer chips but only a few are officially approved so that you don't lose insurance coverage.

If I drive those speeds there are usually no cars around. It's really not easy to find a suitable stretch. 250 kph is a piece of cake, at 300 you feel like the car wants to take off at every hill. Every bend becomes a right angle, your braking distance exceeds 300 meters, which means that if something is blocking your way 280m in front of you, you're dead because you are crashing into it with over 100 kph. Your brain cannot cope with the input and you'll experience tunnel vision (but practice can reduce that) and no one, absolutely no one expects you to go that fast, so on a two-lane autobahn - out of the question. Three lanes at least with almost no cars.

I've done 280 (real speed) pretty often - no problem with that big V12. But beyond that acceleration is virtually non-existent. Real 300 kph I did exceed only once so far. I may have surprised others but I didn't go that fast in order to do so. Still waiting for such an occasion.

...Mike