E93 owners... Question :

[DrVolkl]

Does the cowl shake on this car seem to be excessive with the roof down? I feel like I get way too much vibration through my car with the roof open. In fact, on the way home from the dealership the day I bought it, I went right to the tire store to have all 4 wheels balanced because I thought something was off.

Still seems excessive.

Any extra bracing out there or aftermarket things I can do? Or is this just how it is.

My NSX with the targa roof off had a little... like 5/10 on my level... my Porsche 997 cab I'd rate a 1/10 and this car is like an 8/10. Seems way to high! Drove my buddies Z4 and it was close to a 1... (made up scale just my opinion)

Thoughts?

[NashvegasR]

I'll be honest -- every review of the E93 M3 and 335 I read said "no cowl shake".

Then I bought a 2009 E93 without actually having test driven one... (but a few E92 M3's)... and I noticed on the first drive -- with top DOWN there is definitely just a wee bit of cowl shake. You are not wrong. I honestly could not believe that the car mags could write "no cowl shake" when in fact it *is* there. I define cowl shake as the rear view mirror slightly moving left/right as compared to me not moving. Not a ton, but it's there.

Interestingly -- With the hardtop UP, I get zero noticeable shake. The structure must really firm things up.

Two points of comparison:

1) I did drive a 2014/2015 Camaro convertible in Las Vegas on a business trip recently -- and it made me realize how absolutely rock solid the M3 is. Tons of awful shaking... so we are not as bad as other cars, but it's there.

2) Friend of mine used to have an early 2000's e46 convertible (is that what they are called). It had a ton of cowl shake. Way more than my 2009 M3 E93.

[smyles]

I wonder if vibrations from the folded roof add to it.

[mjposner]

I have noticed much at all, but I live in a land with decent roads. Try teh door open test,perhaps car was in an accident. Also do you have edc on?

[burtonsbs5114]

I also have not noticed much. There are braces on the under-body. I have read about people removing them to fit aftermarket exhaust. You may want to check to make sure they are still there.

[DrVolkl]

Ok, well the roads here are REALLY bad, however the first time I felt it I was driving on the highway and thought my rims were off balance.... I get a lot of vibration through the steering wheel and stuff... like something is off. With the roof up it feels really solid... but there's a big difference with it down.

I'll get under the car soon as my aftermarket exhaust is on the way, just wish I knew what I was looking for lol.

Maybe something is wrong with the suspension... it is a 2008... 37k miles.

[fastmike]

I think the cowl shake is bad, but I did notice it was much worse before I realized one of my front wheels was bent.

[wildwestm3]

OK, so I must be the lucky one here. I have no cowl shake or vibration at all, and it has 72K miles on it. I've been on many "spirited" drives with various clubs with the top down on back roads and nothing. I love this car!

[burtonsbs5114]

Originally Posted by DrVolkl

Ok, well the roads here are REALLY bad, however the first time I felt it I was driving on the highway and thought my rims were off balance.... I get a lot of vibration through the steering wheel and stuff... like something is off. With the roof up it feels really solid... but there's a big difference with it down.

I'll get under the car soon as my aftermarket exhaust is on the way, just wish I knew what I was looking for lol.

Maybe something is wrong with the suspension... it is a 2008... 37k miles.

They are bars that go from the outside of the chassis to around the middle of the car at approximately a 45 degree angle. They both meet at the same place and bolt into the center of the chassis. My AA exhaust came with a spacer so the AA pipes would fit under the bars.

[SWOT1]

Yes, definitely a little shake with the top down (only going over bumpy roads), but not bad at all. SOLID with the top up!

[MCS]

Structurally, It feels a little less stiff than my previous car (E90) but I'll trade it for the Convertible experience.

I'm not tracking the car, so a little shake when going over railroad tracks or extremely crappy roads is expected (Especially when turning)

[DrVolkl]

Yeah, it's something I can live with, just seemed to be more than I expected. I ride in my buddies Z4 and it feel super solid. I know it's not fair due to the length of our cars, but I kinda wondering if there isn't something up.

So no one sells any aftermarket bracing? Or does the car already have everything it needs? I can't imagine doing anything aftermarket that's already there is going to help.
(engine strut bars, etc)

[SheaButter]

Sorry I'm not going to be much help here, I don't have any cowl shake. But then again I installed my exhaust the day I got my M3. With all of the excess noise, I don't think I'd be able to tell if my car was shaking.

HOWEVER I just realized why my gas mileage is worse than most other M3 owners.... I have the top and windows down on just about every trip where it's comfortable.

[DrVolkl]

Originally Posted by SheaButter

Sorry I'm not going to be much help here, I don't have any cowl shake. But then again I installed my exhaust the day I got my M3. With all of the excess noise, I don't think I'd be able to tell if my car was shaking.

HOWEVER I just realized why my gas mileage is worse than most other M3 owners.... I have the top and windows down on just about every trip where it's comfortable.

What's your mpg at? I think I got 14.8 out of my first full tank...

Not exactly stellar.

[SheaButter]

Originally Posted by DrVolkl

What's your mpg at? I think I got 14.8 out of my first full tank...

Not exactly stellar.

I know people won't believe me when I say I drive moderately, I average somewhere around 12-13. Freeways are different here in SoCal though... In Seattle 70mph to MAYBE 75 is considered driving pretty fast (in terms of speeding tickets). Here in SoCal the flow of traffic is usually between 80-85 at around 3600-3700 RPM's, so gas mileage on the freeway doesn't level out city driving.

[burtonsbs5114]

I average around 15 mpg with about 70 city / 30 highway.

[dallas06m3]

Originally Posted by burtonsbs5114

They are bars that go from the outside of the chassis to around the middle of the car at approximately a 45 degree angle. They both meet at the same place and bolt into the center of the chassis. My AA exhaust came with a spacer so the AA pipes would fit under the bars.

my 2009 E93 M3 has significantly less cowl shake than my 2006 E46 M3 vert did. The E46 had drastically less cowl shake than my 94 Mustang GT vert. So, in my opinion, the E93 is pretty solid with the top down. I am surprised you are having so much noticeable shake. I think you should spend some time making sure your tires, wheels, suspension, and bracing are all in proper order. Good luck.

I get 16.5 to 18.0 driving around Dallas every day.

[SaNGRia]

i feel pretty solid as well!

Originally Posted by wildwestm3

OK, so I must be the lucky one here. I have no cowl shake or vibration at all, and it has 72K miles on it. I've been on many "spirited" drives with various clubs with the top down on back roads and nothing. I love this car!