How stable is the E89 at high speed?

sunnydays · Post by **sunnydays** » Wed Sep 22, 2021 4:06 pm

Title really, has anyone had their 35i / 35is at 180mph+? Any front end lightness or did it feel well planted....

Does anyone have any aero figures for the E89?

enuff_zed · Post by **enuff_zed** » Wed Sep 22, 2021 5:53 pm

sunnydays wrote: ↑Wed Sep 22, 2021 4:06 pm Title really, has anyone had their 35i / 35is at 180mph+? Any front end lightness or did it feel well planted....

Does anyone have any aero figures for the E89?

Of course, if you get no replies you'll have to make a decision.
Either no-one has ever gone that fast, or yes they get fatally unstable

keving1 · Post by **keving1** » Wed Sep 22, 2021 6:24 pm

They are limited to 155mph

R.E92 · Post by **R.E92** » Wed Sep 22, 2021 6:41 pm

I felt uneasy past 150 but the car felt OK if a little light at the front, certainly more comfortable at 150 than a E92 but I don't think I'd have the balls to take it to 180.

At those speeds I get paranoid about hitting wildlife. I imagine a badger at 180 would cause problems

I think opinions on stability will vary depending on what others cars people have experience in and also how well the the car is setup. Any deviation in wheel balance or alignment would make any car feel uneasy even past 100.

Number5 · Post by **Number5** » Wed Sep 22, 2021 8:08 pm

If you think about it, you can be driving two completely different cars within seconds.
The metal roof (and rear windscreen) are pretty heavy items alone. When driving with the roof up, this weight is sat between the front and rear axles. As soon as you drop the roof away andinto the boot, all that weight has moved and sits on and behind the rear axle, so if you are throwing the car around you suddenly have a light front end and tail happy rear...

I'm sure someone will be able to tell us the weight of the roof alone ?

The.Analyst · Post by **The.Analyst** » Wed Sep 22, 2021 8:45 pm

I would think the changes in aerodynamics with the roof moving into the boot would have a more profound effect on straight line stability?

With the roof up the profile looks like an upside aerofoil..so as it gets faster it will tend to lift…with the roof down the aero foil will be destroyed so no lift..maybe better stability?

Pondrew · Post by **Pondrew** » Wed Sep 22, 2021 10:46 pm

Have we morphed into a different dimension with this thread? Are you seriously talking about E89 Z4s, or some Italian exotica?

My teeth have all been destroyed by driving on a British road at 30mph in mine

Marcoose · Post by **Marcoose** » Thu Sep 23, 2021 12:42 am

If the stock E89 reaches ‘real’ 180mph, I wouldn’t try it. Modern BMW stock cars aren’t builr for abuse. It’s the sad state of the auto industry. A track spec E89 might, though.

Busterboo · Post by **Busterboo** » Thu Sep 23, 2021 1:50 am

Number5 wrote: ↑Wed Sep 22, 2021 8:08 pm If you think about it, you can be driving two completely different cars within seconds.

Not really. First you have to slow to 3 mph, wait 19 seconds, accelerate again to about 120mph, when you then discover that life with the roof down ain't that much fun.

Busterboo · Post by **Busterboo** » Thu Sep 23, 2021 8:28 am

p.s. As for the front end with the roof up, my experience in my Z is that it begins to get 'floaty' above 140 and, even if it would go, I certainly wouldn't take it to 180. (My 911, with a nominal top speed of 178, was the same at 160.)

BeardyJon · Post by **BeardyJon** » Thu Sep 23, 2021 10:32 am

I got nervous taking it past 110mph so I wouldn't wanna go any higher than that.

Pondrew wrote: ↑Wed Sep 22, 2021 10:46 pm Have we morphed into a different dimension with this thread? Are you seriously talking about E89 Z4s, or some Italian exotica?
My teeth have all been destroyed by driving on a British road at 30mph in mine

I really don't think (/hope) anyone here is considering doing 180mph on British roads.

R.E92 · Post by **R.E92** » Thu Sep 23, 2021 11:18 am

BeardyJon wrote: ↑Thu Sep 23, 2021 10:32 am I got nervous taking it past 110mph so I wouldn't wanna go any higher than that.

Pondrew wrote: ↑Wed Sep 22, 2021 10:46 pm Have we morphed into a different dimension with this thread? Are you seriously talking about E89 Z4s, or some Italian exotica?
My teeth have all been destroyed by driving on a British road at 30mph in mine
I really don't think (/hope) anyone here is considering doing 180mph on British roads.

Why not? Our motorways are straight and flat enough.

Other than some arbitrary speed limits there's no difference between doing 180 on an unrestricted autobahn and the M6 or M40.

BeardyJon · Post by **BeardyJon** » Thu Sep 23, 2021 11:58 am

Yes, but at least Autobahn users know to expect other high speed drivers and will drive accordingly.

tiglon · Post by **tiglon** » Thu Sep 23, 2021 12:12 pm

BeardyJon wrote: ↑Thu Sep 23, 2021 11:58 am Yes, but at least Autobahn users know to expect other high speed drivers and will drive accordingly.

This, and traffic density.

Coincidentally though, the Skyline that was made famous by being stopped doing 197mphon the A1M is currently up for auction in Japan...

R.E92 · Post by **R.E92** » Thu Sep 23, 2021 12:16 pm

BeardyJon wrote: ↑Thu Sep 23, 2021 11:58 am Yes, but at least Autobahn users know to expect other high speed drivers and will drive accordingly.

I wouldn't consider going anywhere near that speed if there was anything else on the road. The M6 north of Preston is a good stretch for that, outside of holiday season you can be the only car for miles.

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