Top speed reached with a 2011 bmw 320d

[P1000]

imp:
I went past the 250km/h mark once, but that was pre-garmin, so I dont know the true speed
All I remember was my mother in law yelling: "Man I never new my broom was this fast!!" :mmm:

Top is 221km/h on garmin car was out of boost! Can't remember what the clock said!

coisman, did your MIL's broom also run out of boost? :biglol: :roflol:

 

[Coisman]

imp:
P1000, Yip, it did, not enough beans the previous night... :mmm:

 

[Sankekur]

Cois aren't you referring to gas :rollsmile:

 

[Coisman]

imp:
O yea, sorry Sank, She ran out of boost when her home-made Hairdryer-turbo conversion ran out of extention cord... :mmm:

 

[Sankekur]

Good glad we got that sorted out, don't want anyone to be misled :biglol:

 

[menno11]

The diesel runs out of steam (i.e. diesel cant burn quick enough in chamber before being pumped out) at about 4250rpm. With the gearing on the 320d, the true top speed in 6th gear is 235km/h at 4300rpm.

Now depending on your tire size and condition of tires, the speedo will give a reading of about 240- 245km/h.

on my own private testing facility we tested this several times and the results were the same every time, except if you accelerate hard and on a downhill, then you can reach about 250km/h (on speedo), but it cant be maintained.

So unless you get a different final gear on your gearbox, you will never be able to go quicker, even with software modifications.

 

[killua]

The diesel runs out of steam (i.e. diesel cant burn quick enough in chamber before being pumped out) at about 4250rpm. With the gearing on the 320d, the true top speed in 6th gear is 235km/h at 4300rpm.
...
So unless you get a different final gear on your gearbox, you will never be able to go quicker, even with software modifications.

If that were true, then there wouldn't be a difference in top speed between the 130kw, 135kw and tuned (acs or bmw) versions. The gearing is the same, but they all top out at different speeds. The top speed here is dictated in the same way as NA petrol cars, thus, drag/frontal area/friction and power/gearing. The diesel just "feels" like it runs out of "steam" because the torque curve falls off. This is due to the combustion characteristics of diesel as a fuel, but it isn't a sudden stop in torque as you suggest.

I suspect that adding enough boost(power) to the 320d, it will top out at 4800RPM where the real drop-off happens :rollsmile:

Or am I missing something?

 

[moranor@axis]

from what ive seen on the forum the diesels seem to gain more low end when tuned...

 

[killua]

from what ive seen on the forum the diesels seem to gain more low end when tuned...

Yes, due to the phenomena describe by menno11... but still, power dictates top speed. They all do gain power, which increase the top speed, using the same gearbox

 

[moranor@axis]

but it all depends on rpm because if you only get a slight power gain in the higher rpm the top speed wont gain much...

im sure there must be some 320d dyno graphs we can look at to say for sure...

i dont see the point of top speed anyway... as long as it can reach 200 who cares... how fast it gets there is way more important...

 

[P1000]

i dont see the point of top speed anyway... as long as it can reach 200 who cares... how fast it gets there is way more important...

:bravo:


Exactly!

 

[killua]

but it all depends on rpm because if you only get a slight power gain in the higher rpm the top speed wont gain much...

im sure there must be some 320d dyno graphs we can look at to say for sure...

i dont see the point of top speed anyway... as long as it can reach 200 who cares... how fast it gets there is way more important...

This is most I have (guestimations based on marketing material):

RED is the stock 320d 135kw, and BLUE is ACS tune which has 155kw... So the torque gain is huge, but power is less. But there still is a gain...

It is true what most are saying, the top speed gain will be less than you would expect if increasing the power, because of the gearing....

I agree with you and p1000, top speed is trivial.... :rollsmile: Except if you drive a bakkie with a top speed of 130km/h :argh:

 

[moranor@axis]

im not sure that graph is right... why does it start out at lower torque than stock?

here is ///MOS1TEDs dyno

even though most of the gain is low down there is still quite a good gain up top which will help top end...

 

[killua]

im not sure that graph is right... why does it start out at lower torque than stock?

even though most of the gain is low down there is still quite a good gain up top which will help top end...

Its trivial... Its just different sources, below 1500rpm it doesnt matter anyway... I cant seem to get consistant figures for low down torque...

It doesnt matter anyway, because we are only interested in the normal operating region.

 

[moranor@axis]

yes at that rpm id does not matter... i just found it odd

maybe post the power graph because its more useful here

 

[killua]

yes at that rpm id does not matter... i just found it odd

maybe post the power graph because its more useful here

And, please ignore the graph below 1500rpm... :fencelook:
But the power curve has a very obvious shape and peak...

 

[moranor@axis]

whoa... that drop off looks horrible :rollsmile:

looks like the 330d has much more potential for top end speed, but a tune will definitely help the 320d get a higher top speed...

 

[killua]

whoa... that drop off looks horrible :rollsmile:

looks like the 330d has much more potential for top end speed, but a tune will definitely help the 320d get a higher top speed...

Bring your 323i up here to the reef and see how horrible the drop-off looks... And I hope you like the e90's tail lights, because thats all you will be seeing.... :roflol:

But be fair, compare the drop-off with other diesels, the 320d is NOT bad. AND remember that power peak is at 4000rpm, so everyting past that is bonus. All my previous diesels did not even want to rev past the 3900rpm mark. With the 320d it goes all the way to 4800RPM.... And still feels strong way past 4000rpm. The power curve for the 330d will look exactly the same, just higher....

 

[drugekull]

it would be nice to get a comparitive torque and power graph between say a 325i or 330i and a 320d does anyone have that

That drop off does look a bit grim but I supposed it gets its high torque so early it can pull a bigger gear than a petrol would so I suppose it all evens out at the end

 

[killua]

it would be nice to get a comparitive torque and power graph between say a 325i or 330i and a 320d does anyone have that

That drop off does look a bit grim but I supposed it gets its high torque so early it can pull a bigger gear than a petrol would so I suppose it all evens out at the end

I have all three, but its useless comparing diesel and petrol torque curves without doing the torque dividing through the gearbox. The diesel gearbox ratios sacrifice torque for rpm reach, otherwise it would be annoying to have to change gears much more often (problem with bakkies).