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      06-18-2012, 10:08 AM   #1
Invadermoose
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question regarding convertible and tracking

I look at the convertible vs coupe threads and I always see the same "sacrifices". Weight, appearance, speed, handling, and tracking.

Now, It's undeniable that all of those are worse than if it was a coupe, but I'm not sure about tracking. I know tracks disallow the use of softtop convertibles, but I thought hard tops were allowed at all tracks?

And with some mods I think a convertible could be even better than a coupe. I've never owned a car I havent supercharged, so I think I already see where my E93 is going. While I'm on the topic, are there any issues with supercharging a convertible?
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      06-18-2012, 10:34 AM   #2
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Tracks and event organizers don't flat-out deny soft-tops. Some do, but others allow them as long as you have a roll bar or some pop-up roll bar mechanism, which BMWs do. But to use a convertible on a track, BOTH the track owners AND the event organizer hosting your particular track day need to approve.

As for hardtop convertibles, they're not viewed any differently because even with a hardtop, a vert's roof is not an integral part of its body structure, and as such doesn't have the same impact absorption capabilities if you roll or (worse) get hit by another car in the roof while your car is lying on its side. Scary as it sounds, the latter scenario is exactly why even coupes have roll cages at higher levels, because any well-designed roof can handle the impact of just about any roll on its own.
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Last edited by jphughan; 06-18-2012 at 10:43 AM.
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      06-18-2012, 11:13 AM   #3
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Quote:
Originally Posted by Invadermoose
I look at the convertible vs coupe threads and I always see the same "sacrifices". Weight, appearance, speed, handling, and tracking.

Now, It's undeniable that all of those are worse than if it was a coupe, but I'm not sure about tracking. I know tracks disallow the use of softtop convertibles, but I thought hard tops were allowed at all tracks?

And with some mods I think a convertible could be even better than a coupe. I've never owned a car I havent supercharged, so I think I already see where my E93 is going. While I'm on the topic, are there any issues with supercharging a convertible?
A convertible can not match the structure rigidity of a car with fixed a,b,c pillars.

That being said, lately I have been driving with my windows rolled down on my E90 to hear the beautiful soundtrack of the S65. I am sure, with the top down, that would be even more enjoyable and a very strong point when deciding to buy a vert.
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      06-18-2012, 01:03 PM   #4
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Check with the track and the organizer of the event as they vary on their allowance of the E93; the convertible tracks very well, but for the added weight of course. Since you are in FL, both Homestead and Sebring allow for the E93, don't know about PBIR. Hooked on Driving and Chin Motorsports allow the E93 in the non-advanced groups. I don't think BMWCCA allows them.
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      06-18-2012, 07:00 PM   #5
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Quote:
Originally Posted by Invadermoose View Post
I look at the convertible vs coupe threads and I always see the same "sacrifices". Weight, appearance, speed, handling, and tracking.

Now, It's undeniable that all of those are worse than if it was a coupe, but I'm not sure about tracking. I know tracks disallow the use of softtop convertibles, but I thought hard tops were allowed at all tracks?

And with some mods I think a convertible could be even better than a coupe. I've never owned a car I havent supercharged, so I think I already see where my E93 is going. While I'm on the topic, are there any issues with supercharging a convertible?
you have a strange user name
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      06-18-2012, 11:15 PM   #6
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Quote:
Originally Posted by jphughan View Post
Tracks and event organizers don't flat-out deny soft-tops. Some do, but others allow them as long as you have a roll bar or some pop-up roll bar mechanism, which BMWs do. But to use a convertible on a track, BOTH the track owners AND the event organizer hosting your particular track day need to approve.

As for hardtop convertibles, they're not viewed any differently because even with a hardtop, a vert's roof is not an integral part of its body structure, and as such doesn't have the same impact absorption capabilities if you roll or (worse) get hit by another car in the roof while your car is lying on its side. Scary as it sounds, the latter scenario is exactly why even coupes have roll cages at higher levels, because any well-designed roof can handle the impact of just about any roll on its own.
^ Agree.

One other comment: When I took the factory tour in Munich, the guide said that all of the steel in an M3 comes from Germany -- except on the E93 convertible, the steel around the front window (A pillar, I think), lower and upper frame, and extensions to the engine bay was a special steel imported from Japan to bolster the vehicle during roll-over. My thought is that having that super-metal in the front, plus the ROPS in the back, could make the E93 safe or as-safe as a full-fledged rooftop (without a containment area, I'll give on that.) But I have also seen more than a half-dozen roll-overs of normal vehicles, and the roofs of these cars weren't the best displays of structural integrity either.

OP: Now you have me thinking that I'm off to search for videos or statistics of rollovers in E93, E92, E90's to see what anecdotal info exists. (I need a hobby.)
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      06-19-2012, 08:26 AM   #7
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Quote:
Originally Posted by VMcV3y View Post
When I took the factory tour in Munich, the guide said that all of the steel in an M3 comes from Germany -- except on the E93 convertible, the steel around the front window (A pillar, I think), lower and upper frame, and extensions to the engine bay was a special steel imported from Japan to bolster the vehicle during roll-over.
Did not know that - thanks.
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      06-19-2012, 08:58 AM   #8
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I've been searching on-line this morning for details on the specific steel used, but have not found it yet. I have found a reference to boron steel...

However, quite interestingly, I have found the official BMW/MINI "Emergency Services Rescue Manual" (English) that advises Fire Departments, etc., on how to dissect the vehicle. It includes a few diagrams and information about the Roll-Over Protection System and then this phrase:
"Structural reinforcements in the A and B pillars are primarily installed in convertibles, Roadsters and Coupes. This is where there are particlar stability requirements on these cars." - Materials, Page 25
Other helpful things you can find here: See pages 119- 120, to view diagrams and learn specifically how to cut apart your convertible (i.e. "1. ... Cut along the upper lateral edge of the windscreen, as far outward as possible, parallel to the A pillar. Remove the roof outer skin on the C pillar with a spreader and cut the folding-top frame using an angle grinder.")

This manual is good for all BMW models, so in case an E90 or E88 user also wants to dismantle your car by cutting it, knock yourself out!

Site for PDF download:

https://oss.bmw.de/rettungsleitfaden...l_BMW_Mini.pdf


..
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Last edited by VMcV3y; 06-19-2012 at 09:01 AM. Reason: fixed a copy/paste error
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      06-19-2012, 11:30 AM   #9
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Verts are great. I had an E46 M3 vert for over 5 years and loved every second, the extra weight and less rigidity didn't really bother me. What did was the track thing, no way was I going to track it whether the organizers would allow it or not. Yes the windshield frame is reinforced and there is the roll over protection behind the seats, but that just is not enough if I was to roll it.

Everybody has their own level of risk tolerance and you will find track day organizers that allow verts. If you really want the fun of a convertible, don't let the weight issue keep you away from it. If you are serious about going to the track, I would highly recommend a coupe or sedan.
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