Not joined yet? Register for free and enjoy features such as alerts, private messaging and viewing latest posts and topics.

Why does the 35is speedo stop at 160mph?

Specific discussion about the E89 2009 Z4 (sDrive35is, sDrive35i, sDrive30i, sDrive23i)
ibroker
Member
Member
Posts: 142
Joined: Sun Nov 06, 2016 8:27 pm

Why does the 35is speedo stop at 160mph?

Post by ibroker » Wed Jul 19, 2017 7:12 pm

At 340hp the 35is would never make 180mph. Even unlimited it would struggle to pass 160ish. The jump in horse power required at those speeds to pass 165plus to make 180mph is massive.

Its a great car without question, but kid yourself not. Its not in that league.
Z4 35is Valencia Orange. Custom Quad Exhausts Custom 400hp Remap. :evil:

User avatar
Smartbear
Lifer
Lifer
Posts: 13685
Joined: Wed Feb 05, 2014 6:54 pm
Location: a barn in Somerset

Why does the 35is speedo stop at 160mph?

Post by Smartbear » Wed Jul 19, 2017 7:45 pm

buzyg wrote: Wed Jul 19, 2017 6:49 pm
Smartbear wrote: Wed Jul 19, 2017 6:25 pm
buzyg wrote: Wed Jul 19, 2017 6:19 pm Ok I found some figures.

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). :thumbsup:
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)

From these I am struggling to see how a standard 35IS could possibly be several mph faster than a E85/86 ///M. :?

Can any one shed any more light?
How does the torque output compare between the 2 cars?
Rob
Rob, the torque affects the acceleration not the top speed.
Relative Top speed is largely governed by. Frontal area, bhp & the cd figure.
True, but I was thinking the wind resistance at those speeds is massive & would need huge torque to punch through it? Top speed in a vacuum would be bhp limited however-does that make sense? :?
Rob
Image

e89 Sdrive 20i, plenty of mumbo & good economy-the thinking bears z4
e89 Sdrive 30i, this ones busted, pass me another...
e85 3.0si sold

sad_old_man

Why does the 35is speedo stop at 160mph?

Post by sad_old_man » Wed Jul 19, 2017 8:07 pm

Yorkie Z wrote: Wed Jul 19, 2017 6:14 pm Because there driven by pensioners who get scared after 60mph :poke: :rofl:
:P :P

Yes I am, yes I do, but yesterday I went round a corner at 31mph and didn't spin out once! I love my Z4! Also some times when I close my eyes I can't see anything! :rofl: :rofl: :rofl: :rofl: :P :tumbleweed: :tumbleweed: :tumbleweed:

User avatar
buzyg
Legend
Legend
Posts: 26421
Joined: Fri May 20, 2011 6:11 pm
Location: Cornwall

Why does the 35is speedo stop at 160mph?

Post by buzyg » Wed Jul 19, 2017 8:34 pm

Smartbear wrote: Wed Jul 19, 2017 7:45 pm
buzyg wrote: Wed Jul 19, 2017 6:49 pm
Smartbear wrote: Wed Jul 19, 2017 6:25 pm

How does the torque output compare between the 2 cars?
Rob
Rob, the torque affects the acceleration not the top speed.
Relative Top speed is largely governed by. Frontal area, bhp & the cd figure.
True, but I was thinking the wind resistance at those speeds is massive & would need huge torque to punch through it? Top speed in a vacuum would be bhp limited however-does that make sense? :?
Rob
Rob

Next time your really really bored, have a good read here.

https://metinmediamath.wordpress.com/20 ... ti-veyron/

Using these formula you can estimate the maximum theoretical speed. In practice this then needs to be teamed to the engines power curve and gear ratios. The car will hit top speed where the max horsepower figure is reached and the gearing allows, which for the MR is at 171mph in 5th, though the max theoretical speed is a few mph above that, so with a different final ratio or larger tyres, you might manage a few more mph. But by 6th gear the MR is way off the power curve so is slower.

Being that way inclined, I did the maths, but I'm keeping my spread sheet to my self for fear of sending the entire forum into catatonic stupor. Needless to say I doubt the high figures suggested above and await further evidence. :thumbsup:

Any one still awake. :D
Image

User avatar
Pastry
Senior Member
Senior Member
Posts: 2288
Joined: Wed May 25, 2016 5:01 pm
Location: South East

Why does the 35is speedo stop at 160mph?

Post by Pastry » Wed Jul 19, 2017 8:53 pm

sunnydays wrote: Wed Jul 19, 2017 6:32 pm
buzyg wrote: Wed Jul 19, 2017 6:19 pm Ok I found some figures.

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). :thumbsup:
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)

From these I am struggling to see how a standard 35IS could possibly be several mph faster than a E85/86 ///M. :?

Can any one shed any more light?

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
Spoken like a true E89 driver ... :roll:
991 Carrera 2S
Now gone:
2008 Z4MR Midnight Blue Metallic
2006 Z4 3.0si sport Ruby Black
2006 Z4 3.0si sport Titanium Silver
2010 Z4 23i Msport and a 3.0i

Online
User avatar
mr wilks
Legend
Legend
Posts: 21894
Joined: Wed Jul 04, 2012 10:02 pm
Location: Lancashire

Why does the 35is speedo stop at 160mph?

Post by mr wilks » Wed Jul 19, 2017 8:58 pm

Pastry wrote: Wed Jul 19, 2017 8:53 pm
sunnydays wrote: Wed Jul 19, 2017 6:32 pm
buzyg wrote: Wed Jul 19, 2017 6:19 pm Ok I found some figures.

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). :thumbsup:
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)

From these I am struggling to see how a standard 35IS could possibly be several mph faster than a E85/86 ///M. :?

Can any one shed any more light?

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
Spoken like a true E89 driver ... :roll:
He forgot the straight line bit :P :poke: :D
3 ZMRs
3 E89s
5 Si coupes
5 Si roadsters
997 C4
TTRS
F82 M4
MK7 Golf Gti
current Bmw 6 Gran Turismo

User avatar
Pastry
Senior Member
Senior Member
Posts: 2288
Joined: Wed May 25, 2016 5:01 pm
Location: South East

Why does the 35is speedo stop at 160mph?

Post by Pastry » Wed Jul 19, 2017 9:08 pm

mr wilks wrote: Wed Jul 19, 2017 8:58 pm
Pastry wrote: Wed Jul 19, 2017 8:53 pm
sunnydays wrote: Wed Jul 19, 2017 6:32 pm


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
Spoken like a true E89 driver ... :roll:
He forgot the straight line bit :P :poke: :D
:lol: I remember only too well how even my old 23i Msport had enough power to push the handling to its limits, Im sure when they gave it 140 more horses they improved the handling? :wink: :D
991 Carrera 2S
Now gone:
2008 Z4MR Midnight Blue Metallic
2006 Z4 3.0si sport Ruby Black
2006 Z4 3.0si sport Titanium Silver
2010 Z4 23i Msport and a 3.0i

Online
User avatar
mr wilks
Legend
Legend
Posts: 21894
Joined: Wed Jul 04, 2012 10:02 pm
Location: Lancashire

Why does the 35is speedo stop at 160mph?

Post by mr wilks » Wed Jul 19, 2017 9:11 pm

Pastry wrote: Wed Jul 19, 2017 9:08 pm
mr wilks wrote: Wed Jul 19, 2017 8:58 pm
Pastry wrote: Wed Jul 19, 2017 8:53 pm

Spoken like a true E89 driver ... :roll:
He forgot the straight line bit :P :poke: :D
:lol: I remember only too well how even my old 23i Msport had enough power to push the handling to its limits, Im sure when they gave it 140 more horses they improved the handling? :wink: :D
Eerrrr no mate they didn't :P the seats are much more comfy though as you wallow in the bends :D
3 ZMRs
3 E89s
5 Si coupes
5 Si roadsters
997 C4
TTRS
F82 M4
MK7 Golf Gti
current Bmw 6 Gran Turismo

User avatar
Pastry
Senior Member
Senior Member
Posts: 2288
Joined: Wed May 25, 2016 5:01 pm
Location: South East

Why does the 35is speedo stop at 160mph?

Post by Pastry » Wed Jul 19, 2017 9:21 pm

mr wilks wrote: Wed Jul 19, 2017 9:11 pm
Pastry wrote: Wed Jul 19, 2017 9:08 pm
mr wilks wrote: Wed Jul 19, 2017 8:58 pm

He forgot the straight line bit :P :poke: :D
:lol: I remember only too well how even my old 23i Msport had enough power to push the handling to its limits, Im sure when they gave it 140 more horses they improved the handling? :wink: :D
Eerrrr no mate they didn't :P the seats are much more comfy though as you wallow in the bends :D
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 :poke: :D
991 Carrera 2S
Now gone:
2008 Z4MR Midnight Blue Metallic
2006 Z4 3.0si sport Ruby Black
2006 Z4 3.0si sport Titanium Silver
2010 Z4 23i Msport and a 3.0i

User avatar
BMWZ4MC
Lifer
Lifer
Posts: 6337
Joined: Sun Sep 13, 2009 4:24 pm
Location: Back in the sunshine

Why does the 35is speedo stop at 160mph?

Post by BMWZ4MC » Wed Jul 19, 2017 10:32 pm

mr wilks wrote: Wed Jul 19, 2017 8:58 pm
Pastry wrote: Wed Jul 19, 2017 8:53 pm
sunnydays wrote: Wed Jul 19, 2017 6:32 pm


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
Spoken like a true E89 driver ... :roll:
He forgot the straight line bit :P :poke: :D
He also forgot to tell us how much better it sounds than the ///M :poke:
Image
Z4MC - heavily fettled for track use
Lotus Exige - sensible daily driver on the mods slippery slope
Westfield SEiW - in hibernation
Modified RS4 Avant - back in Blighty
S2000 GT - gone

User avatar
R.E92
Senior Member
Senior Member
Posts: 1644
Joined: Wed Dec 04, 2013 10:10 am

Why does the 35is speedo stop at 160mph?

Post by R.E92 » Wed Jul 19, 2017 10:36 pm

The M cars often come with some sort of upgrade package "track package" that raises the top speed limiter. I'm thinking that's why the speedo on modern M cars is higher than the limit.

I'd be surprised if the 35is couldn't reach 180, must be someone with a stock car that's been on the autobahn.
The stated power figures for the 35is are quire conservative.

User avatar
sunnydays
Member
Member
Posts: 983
Joined: Fri Sep 23, 2016 7:50 am

Why does the 35is speedo stop at 160mph?

Post by sunnydays » Wed Jul 19, 2017 10:55 pm

buzyg wrote: Wed Jul 19, 2017 6:38 pm
sunnydays wrote: Wed Jul 19, 2017 6:32 pm
buzyg wrote: Wed Jul 19, 2017 6:19 pm Ok I found some figures.

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). :thumbsup:
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)

From these I am struggling to see how a standard 35IS could possibly be several mph faster than a E85/86 ///M. :?

Can any one shed any more light?

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.....


User avatar
sunnydays
Member
Member
Posts: 983
Joined: Fri Sep 23, 2016 7:50 am

Why does the 35is speedo stop at 160mph?

Post by sunnydays » Wed Jul 19, 2017 10:58 pm

Pastry wrote: Wed Jul 19, 2017 9:21 pm
mr wilks wrote: Wed Jul 19, 2017 9:11 pm
Pastry wrote: Wed Jul 19, 2017 9:08 pm

:lol: I remember only too well how even my old 23i Msport had enough power to push the handling to its limits, Im sure when they gave it 140 more horses they improved the handling? :wink: :D
Eerrrr no mate they didn't :P the seats are much more comfy though as you wallow in the bends :D
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 :poke: :D
Funny how handling always comes up yet the 35is beats the M in almost all track tests :wink:

User avatar
Pastry
Senior Member
Senior Member
Posts: 2288
Joined: Wed May 25, 2016 5:01 pm
Location: South East

Why does the 35is speedo stop at 160mph?

Post by Pastry » Wed Jul 19, 2017 11:11 pm

sunnydays wrote: Wed Jul 19, 2017 10:58 pm
Pastry wrote: Wed Jul 19, 2017 9:21 pm
mr wilks wrote: Wed Jul 19, 2017 9:11 pm

Eerrrr no mate they didn't :P the seats are much more comfy though as you wallow in the bends :D
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 :poke: :D
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 :poke:
991 Carrera 2S
Now gone:
2008 Z4MR Midnight Blue Metallic
2006 Z4 3.0si sport Ruby Black
2006 Z4 3.0si sport Titanium Silver
2010 Z4 23i Msport and a 3.0i

User avatar
sunnydays
Member
Member
Posts: 983
Joined: Fri Sep 23, 2016 7:50 am

Why does the 35is speedo stop at 160mph?

Post by sunnydays » Wed Jul 19, 2017 11:33 pm

Pastry wrote: Wed Jul 19, 2017 11:11 pm
sunnydays wrote: Wed Jul 19, 2017 10:58 pm
Pastry wrote: Wed Jul 19, 2017 9:21 pm

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 :poke: :D
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 :poke:
Im not refuting how the car feels to drive. I am simply refuting people saying it is a poor handling car :). The fact it beats the M around the track speaks volumes

Post Reply