Z4m coupe top speed 300km/hr

[Nikitas_Z4mcoupe]

As its my first post here, I would like to say Hi to everybody and share my following video.
Hope you enjoy it as I did .

[Vanne]

Bloody hell, hope your doing that on one hell of a straight at a circuit mate.

Welcome..

[Nikitas_Z4mcoupe]

Originally Posted by Vanne

Bloody hell, hope your doing that on one hell of a straight at a circuit mate.

Welcome..

No worries, at a remote area late at night with zero traffic......
Thanks man

[GTA Z4MC]

WoW. 300KM's at 4000 RPM.
Unreal.......

[Nikitas_Z4mcoupe]

Originally Posted by GTA Z4MC

WoW. 300KM's at 4000 RPM.
Unreal.......

You mean 8000RPM... my diff is 3.91, at the end I put it to neutral to remove the strain from the engine

[007MCoupe]

That's one hell of a first post! Welcome! What tune do you have?

[Steeler]

Originally Posted by GTA Z4MC

WoW. 300KM's at 4000 RPM.
Unreal.......

Thought the same thing but he wouldn't be getting that acceleration with a lower numerical rear gear

Originally Posted by Nikitas_Z4mcoupe

You mean 8000RPM... my diff is 3.91, at the end I put it to neutral to remove the strain from the engine

What 007 said.......what tune?

[Nikitas_Z4mcoupe]

Originally Posted by 007MCoupe

That's one hell of a first post! Welcome! What tune do you have?

Thanks man!
Currently I am running with SS V1 stepped headers, rpi scoop & cat back exhaust, custom tune and 3.91diff.
All of the above the diff made the biggest difference, lots of torque and higher top speed.
I have some pictures at my albums if you want to have a look at the car from some events-gatherings.....

[Nikitas_Z4mcoupe]

[QUOTE=dbarton62;18726848]Thought the same thing but he wouldn't be getting that acceleration with a lower numerical rear gear

I wish it could but not possible .
With 3.91 ring & pinion you have to go all the way near the rpm limiter to reach 300Km/hr. But it really transforms the car, you just need good tarmac to feel the difference, otherwise it spins a lot....

[Twixboy]

Don't mean to sound negative, but if you did that on a public road you could've easily killed yourself. One bump in the road and you'd go flying out of control. Stay safe man.

[GuidoK]

No gps speed?
That is the only conclusive way to measure if you want to make real conclusions about top speed.
You can use android tracks or some other (free) logger.
GPS is 100% accurate.

[PLCZ4MC]

O wow. I reach only ones 172mph. Well it cannot be 100% as I was not monitoring the speed professional. But I got pretty scare going that high speed. Only ones in my roadster. Never again. Feels very different going 150 mph and going 172mph. And yes I agree with Twixboy in a public rode it felt even worse. Crazy experience but not doing it again.
Nice first post tough. I wonder how you were able to get the camera to record just the speedometer.

[dc_wright]

[QUOTE=Nikitas_Z4mcoupe;18728146]

Originally Posted by dbarton62

Thought the same thing but he wouldn't be getting that acceleration with a lower numerical rear gear

I wish it could but not possible .
With 3.91 ring & pinion you have to go all the way near the rpm limiter to reach 300Km/hr. But it really transforms the car, you just need good tarmac to feel the difference, otherwise it spins a lot....

Unless you recalibrated the speedo after changing to the 3.91 diff, you weren't going an actual 300 KPH. You were going approximately 8% slower......

[GuidoK]

Makes sense. Just like different tyres give errors (and the speed dial itself isnt that accurate too)

Thats why I always use gps if I want to know the actual speed. Everyone carries a gps nowadays in their phone so you can always log your journey and see your top speed.

For performance testing (0-60 or whatever) I use a seperate 10hz gps, so I get a real accurate time. Phone gps chips only have a 1 second refresh interval.

Originally Posted by PLCZ4M

O wow. I reach only ones 172mph. Well it cannot be 100% as I was not monitoring the speed professional. But I got pretty scare going that high speed. Only ones in my roadster. Never again.

I think the coupe will be a bit faster on top speed because I suspect it has a better drag coefficient.
At those kind of speeds I'm always afraid that my rear glass window will shatter or that my hood will tear off completely
The fabric at the back really starts to resonate. I think there may be some kind of vortex at those speeds on the back of the fabric top.

Also above 170mph there is some kind of force on the side windows that sucks them a bit apart and that also creates an ear deafening slit. (at least on my car, maybe I can adjust the windows a bit tighter)

The ragtop is not made for those speeds I guess.

[Nikitas_Z4mcoupe]

[QUOTE=dc_wright;18757916]

Originally Posted by Nikitas_Z4mcoupe

Unless you recalibrated the speedo after changing to the 3.91 diff, you weren't going an actual 300 KPH. You were going approximately 8% slower......

Not true you are changing the diff ratio... each gear will produce 8% less speed at same rpm compared to 3.62, thats why now the car goes 300km/hr at almost 8000rpm with 6th.
not same as reducing the diameter of the wheels - tyres

[Nikitas_Z4mcoupe]

Originally Posted by PLCZ4M

O wow. I reach only ones 172mph. Well it cannot be 100% as I was not monitoring the speed professional. But I got pretty scare going that high speed. Only ones in my roadster. Never again. Feels very different going 150 mph and going 172mph. And yes I agree with Twixboy in a public rode it felt even worse. Crazy experience but not doing it again.
Nice first post tough. I wonder how you were able to get the camera to record just the speedometer.

True, GPS is the only professional way of monitoring performance of the car (0-100 or 100-200km), including top speed but still speedometer is a good indication of how fast you are going...
I just wanted to share with you guys as going through the net, youtube etc I have never seen any other Z4m reaching this speed only M3s
Thanks.....Iphone can fit in between the wheel......

[Nikitas_Z4mcoupe]

Originally Posted by GuidoK

Makes sense. Just like different tyres give errors (and the speed dial itself isnt that accurate too)

Thats why I always use gps if I want to know the actual speed. Everyone carries a gps nowadays in their phone so you can always log your journey and see your top speed.

For performance testing (0-60 or whatever) I use a seperate 10hz gps, so I get a real accurate time. Phone gps chips only have a 1 second refresh interval.


I think the coupe will be a bit faster on top speed because I suspect it has a better drag coefficient.
At those kind of speeds I'm always afraid that my rear glass window will shatter or that my hood will tear off completely
The fabric at the back really starts to resonate. I think there may be some kind of vortex at those speeds on the back of the fabric top.

Also above 170mph there is some kind of force on the side windows that sucks them a bit apart and that also creates an ear deafening slit. (at least on my car, maybe I can adjust the windows a bit tighter)

The ragtop is not made for those speeds I guess.

I fully agree. I had a Z3 roadster and at high speeds was a nightmare.... lots of wind, noise and felt not stable at all. That’s the reason I decided to buy a coupe

[NickyC]

Tell me you weren't holding the camera for that!

[Nikitas_Z4mcoupe]

Originally Posted by NickyC

Tell me you weren't holding the camera for that!

I am crazy but not that much.......

[inTgr8r]

Originally Posted by dc_wright

Unless you recalibrated the speedo after changing to the 3.91 diff, you weren't going an actual 300 KPH. You were going approximately 8% slower......

The diff does not change the speedo.
Pickup point is after the diff

[GuidoK]

Originally Posted by Nikitas_Z4mcoupe

I fully agree. I had a Z3 roadster and at high speeds was a nightmare.... lots of wind, noise and felt not stable at all. That’s the reason I decided to buy a coupe

I don't think the z4 roadster gets unstable at high speeds, but its more that a fabric hood gets a pretty big beating above 250kph.
Especially hoods with a big curvature. Hoods on supersportscars mostly are much flatter as their base sits higher.

[dc_wright]

Originally Posted by inTgr8r

The diff does not change the speedo.
Pickup point is after the diff

My bad! I was thinking there was a speed sensor on the diff that sensed the ring gear teeth like earlier BMWs used...............