Why does the 35is speedo stop at 160mph?

[sunnydays]

I bet if you put two average to semi-decent drivers from this forum next to each other in a manual Z4M and a manual 35is and set them off on a drag race then there would be f**k all in it... Oh wait, the 35is doesn't come in manual right ? Which probably means that time difference is due to electronic reactions and control being superior to human manual input. Which is fine, and I have no problem with by the way. But tbh, reducing these cars to top speeds and straight line performance times completely misses the point of them, especially given that most will never vmax the car, or actually be able to match the manufacturer quoted acceleration times.

Personally that 0.5 sec difference means nothing to me because by 4.4 secs I am already having waaaaay to much fun for it to be legal :lol:

Perhaps not in the Z4M but in the 35is you can utilise launch control as seen below. The manufacturer claim is 4.8s, independant magazine tests put it around 4.4.s.

The video below shows a real world 4.79s
[youtube]1C-fj-8PszQ[/youtube]

The Z4M would be more difficult due to being manual, and lacking launch control

 

[Anonymous]

A bit of Googling gives:

Model BHP Top Speed Acceleration Torque NM
1.8i 153 137 7.8 240
2.0i 181 145 6.7 270
2.3i 201 149 7.1 250
2.8i 241 152 5.3 350
3.0i 254 157 5.9 310
PB Z4 280 160 5.2 380 (computed)
3.5i 301 167 4.9 400
3.5iS 335 173 4.6 450

Enjoy!

Excuse the formatting sure to provoke a storm..

 

[Nanu]

Torque, weight, gear ratios, tyres, downforce.

Considering the 35is spanks the Z4M from 0-60, 0-100 etc.... its not surpising it has a higher top speed

Could you kindly show me some physics, or some official proven figures please. The physics I was taught say it's unlikely.

My calculations based off
Drag coefficient of 0.34
1.96m sqd area
3500lb kerb weight
340 bhp

Gives a theoretical max of 185mph...

One thing you have not accounted for is the under rating of the N54 engines, it was proven that the N54 turbos put out approx 20-30bhp more than factory figures. BMW has done the same on some other turbo engines ie the M4

There is a 35is delimited with a slight tune comfortably hitting 190mph on youtube measured via GPS. Video below.....

[youtube]tJcck9O1jTc[/youtube]

The fact that in this video they are indicating left and right at those speeds evidences the good handling in my book

 

[sunnydays]

A bit of Googling gives:

Model BHP Top Speed Acceleration Torque NM
1.8i 153 137 7.8 240
2.0i 181 145 6.7 270
2.3i 201 149 7.1 250
2.8i 241 152 5.3 350
3.0i 254 157 5.9 310
PB Z4 280 160 5.2 380 (computed)
3.5i 301 167 4.9 400
3.5iS 335 173 4.6 450

Enjoy!

Excuse the formatting sure to provoke a storm..



Z4 numbers.jpg

Very nice, so much for the 35is wont break 160 crew..........

 

[buzyg]

A bit of Googling gives:

Model BHP Top Speed Acceleration Torque NM
1.8i 153 137 7.8 240
2.0i 181 145 6.7 270
2.3i 201 149 7.1 250
2.8i 241 152 5.3 350
3.0i 254 157 5.9 310
PB Z4 280 160 5.2 380 (computed)
3.5i 301 167 4.9 400
3.5iS 335 173 4.6 450

Enjoy!

Excuse the formatting sure to provoke a storm..



Z4 numbers.jpg

Now those figures look far more realistic.

 

[chasBMW]

Well if I ever decide to ditch my fun weekend car that drives as great as it breeding and take up drag racing instead, I know where to look

Funny how handling always comes up yet the 35is beats the M in almost all track tests :wink:

Heard it all before :roll: I've had both, so I know how they drive

I have been lucky enough to own both to own both an E86 & E89 and I would agree with Mr(?)Pastry , as such the E89 isnt a bad car but on the occasions I drove it like I stole it felt like it was at its limits whereas the E86 didnt

 

[john-e89]

Power is nothing without control. Same corner, same speed, im more concerned about the 35is breaking loose than the M. Both on all but new MPSS's. Not that I drive like a loon, but there's a couple tight corners that are off camber, the M is tighter. I would suggest that a 35is is quicker round a track due to the DCT, you simply cannot change gear as quickly with a manual box, plus there's no throttle lift with the DCT, that and the 35is has more torque.

Both splendid machines though.

 

[GuidoK]

E85 CD .35, frontal area 1.91 m2, 338bhp @ 7900rpm (Precisely the RPM needed for the E85 to reach it's top speed in 5th gear).
E89 CD .34, frontal area 1.96 m2, 335bhp @ 5900rpm ( Alas I don't know the power curve or max speed in gears/ratio's)

Afaik the z4m has a CD 0,38 and A is 1,92m²
(the front bumper of the z4m certainly isnt designed for top speed with its large vent holes)
So drag for the z4m is 0,7296q and the drag for the e89 is 0,6664q, so considerably lower. (the normal e85 is quite on par it seems with 0,6685, although somehow I still have a hard time believing it because the e89 has a coupe like roof and the e85 roof shape doesnt seem that aerodynamically....)
But I havent checked the e89 figures, and of course that also comes with different bumpers, so differend coefficients..

 

[buzyg]

E85 CD .35, frontal area 1.91 m2, 338bhp @ 7900rpm (Precisely the RPM needed for the E85 to reach it's top speed in 5th gear).
E89 CD .34, frontal area 1.96 m2, 335bhp @ 5900rpm ( Alas I don't know the power curve or max speed in gears/ratio's)

Afaik the z4m has a CD 0,38 and A is 1,92m²
(the front bumper of the z4m certainly isnt designed for top speed with its large vent holes)
So drag for the z4m is 0,7296q and the drag for the e89 is 0,6664q, so considerably lower. (the normal e85 is quite on par it seems with 0,6685, although somehow I still have a hard time believing it because the e89 has a coupe like roof and the e85 roof shape doesnt seem that aerodynamically....)
But I havent checked the e89 figures, and of course that also comes with different bumpers, so differend coefficients..

Good point I meant E86 CD is 0.35, from the BMW brochure

 

[sunnydays]

So now that we have established the car is capable in the region of 173 - 177mph.

It seems simply because its not an 'M' they capped the speedo to 160 which is ridiculous....

 

[Anonymous]

One could argue from a human factors viewpoint..

Normally they are limited to 155 anyway
Better to 'see' the limiter coming in at the 'top of the dial'
If you have a dial that goes to say 200mph then you will be upset when it 'only' does 165 or whatever..

 

[buzyg]

So now that we have established the car is capable in the region of 173 - 177mph.

It seems simply because its not an 'M' they capped the speedo to 160 which is ridiculous....

It's simply as it should be. :wink: :lol: