Palmo

Does anyone know if the top speed of the LCI (March 07 onwards) is limited or not - or is it simply the power output of the engine that cannot achieve anymore?

Top Speed quoted by BMW = 147mph (as opposed to 155mph for both the higher output 530d [manual only as auto = 154mph] & 535d's).

Last Summer I had a trip over to Germany where I had the opportunity to open my car up - I managed a comfortable and easily achieved 149mph (indicated) before the traffic began to build up. It achieved this easily and was still accelerating reasonably - although I do have a STB installed. As this provides more power I wondered if it was this that was obviously aiding the cars speed, but this wouldn't make any difference if the cars top speed was limited - hence my question. My car felt like, given the opportunity of further clear road (which I didn't manage to get), it would have easily have achieved the 155mph mark.

Can anyone confirm?

andy545

155 is the default limit on non M BMW cars. To go beyond and assuming you have the power to do so, you will need to chiptune your DME. I'm not sure if your STB removes any
limit, my guess is that it doesn't.

Palmo

Thanks for the reply - I realise that 155mph is the default limit. However, on my particular model the top speed is quoted as 147mph. As this is essentially the same engine as the 530d but 'detuned' I am unsure if the reduced top speed is as a result of a lower power output i.e. the car simply cannot go any faster or if the car is deliberately limited below the usual 155mph by BMW to stop it treading on the toes of the 530d.

525d (LCI) = 197 hp
530d (LCI) = 235 hp
Difference = 38 hp.

Is 38 hp enough to reduce top speed by 8mph?

My STB does not remove any limiter. As I didn't have a real chance to go 'beyond 150 mph' it was unclear if my car would have actually continued to 155mph or not, although it did seem to be still accelerating. I'm just curious more than anything.

Jambers

Don' forget speedo accuracy - can over read by 10%...

Palmo

Yeah exactly - that's why I said 'indicated'. Either way, I just want to know if the LCI 525d is electronically limited or if it's down to power why it's top speed is 147mph - it could easily be either!

OverSoft

I'm pretty sure it's just a lack of power. 155mph is fast and a car weighing 1600kg is essentially "underpowered" when it has less than 200bhp.
I've driven 275km/h (170mph) in my chipped 530d (about 265bhp, a little more) and that's really it's limit (the last 5km/u get there really slow).
So at 70bhp less on your 525d, the top speed will be about 25mph less, which sounds about right.

Palmo

Makes sense. In my case I have more than stock (up-to 245 ps with the added STB, although I've not had it on a dyno to verify). Therefore I should have enough power to get to 155mph, but if a lower limiter is fitted this would prevent this. Just annoyed I didn't get a chance to confirm - I was so near (indicated 149mph) but so far......!

Sahil

I have touched down at 250km/hr which is approx 155mph. The car seem to have steam left to push a little more but the limiter didn't let it.