Thinking about safety...add cage to M4 vs M4 GTS?

[rsyring]

I bought a F80 M3 in May b/c I wanted to start doing HPDE track events. I've done a few events now, really like it, and have signed up for another handful of events before the end of the season. My last event was with Chin at the Ozarks, MO track and the instructor said I did really well and should be able to "graduate" to solo at my next event. (baby steps)

This past event was the first time I was at a Chin event and they emphasized safety more than the previous events I went to. I had been thinking about this anyway and planning to get my own helmet (was renting) and Hans device. Then I realized you can't use a Hans device without a cage or harness bar, so had started to look into cages and if that was "necessary" for my level at HPDE events. I've read some people who say they'd never get into a car at a track without a six-point harness and half cage. But then my instructor at this last event just used a hybrid neck restraint and didn't have a cage in her M2 and she had been doing this for a number of years.

Then, on my last lap at this past event, I came around a corner and there was a car that had recently passed me stalled on the track and pointed right at me. Thankfully on the opposite side of the track from my line. I think that solidified for me the reality that it's not just my driving that matters. Things will happen that are out of my control and I should be as prepared as I can be from a safety perspective.

So I decided I was going to put a half cage in my M3 but then realized doing that and keeping it as a DD would be silly. No sense putting a cage into a four-door vehicle. Trade the M3 in and get an M4, then put the cage in.

But then I started looking into cages that can be put into an F82 and found some "bolt-in" ones. I also found people in the forums who said it was pointless to do that, the installation method isn't strong enough to hold up when needed (the legs can just push through the floor pan).

I started looking for a more reputable opinion on putting a cage in an M2 and came across: https://www.roadandtrack.com/car-cul...ur-street-car/ That seemed like a reasonable perspective and I came away thinking I didn't want to be responsible for finding the right fabricator, with the right welding knowledge, to put a cage in my car and then "hope" that it was done right with proper engineering knowledge b/c there's no way to test something like that.

At that point I was pretty overwhelmed. I've committed to my wife to make this new hobby as safe as I can reasonably make it. I even started to look into E92 track builds where the cage was already installed but most of the ones I found were just bolt ins. I found one actual race car that looked like it had all the right safety equipment (and lots of other stuff that would be very overkill at my skill level and usage) but it was $135K!

I finally punted and put some money down on a M4 GTS. But at $92K the expense of this hobby is starting to get out of hand. I found a 2019 F82 that I like for $58K, and I'm sure I could find someone somewhere to put a half-cage in for $10K (?), but I'm still concerned I have no idea of they've done it right. At least with the GTS, presumably, BMW engineers that understand track dynamics and safety have evaluated and approved the cage that is installed by the factory. But at a $25K premium, I'd like to find another sufficient option.

I know this might seem like just an excuse to buy a GTS, but I'd really rather have a less expensive vehicle. Cheaper insurance, not as concerned about damage, etc.

So, just looking for advice on how to think through these things. Complete the GTS purchase and drive on? Or are there more economical options for making an F82 safer with the same level of confidence I can have with the GTS?

Thanks in advance.

[MineralWhiteF80]

Here is my opinion:

A lot of these "bolt in" 4-point cages are really just designed to be a sturdy "harness bar" that allows you run race seats and multipoint safety harness configurations other than the factory seat/3 point harness setup, with the main goal of holding you in place better. Sure, they theoretically should provide some additional protection during a certain type of roll over crash, but if you actually look at the the positioning of the top hoop compared to 'crush line' from the bottom of the windshield to the top of the roll bar hoop, you will see that the roof will still cave in and likely contact the occupant's heads. There are so many ways a car will roll and flip over, the 4-point bar is likely to not do much (in my opinion).

The GTS cage main hoop feet install in a much stronger part of the chassis compared to other off-the-shelf cages that bolt to the thin sheet metal in the floor pan. So the GTS bar 'should' provide more safety if the car was dropped on its roof, but it's too hard to say how much safer it would actually be.

The thing that gets me about the M4 GTS factory setup is that it has the harness bar/half cage installed, but the factory USA spec'd GTS seats don't have the hole provisions in them to properly run shoulder belts through like the European GTS version of the Recaro Pole Position seats do. So even if you get a GTS, you should install a true race seat that can take advantage of the harness bar.

A real safety cage is extremely complex and intrusive with a lot of focus on the windshield, A-pillar, door bars, B-pillar areas that 'cage' the driver. These "bolt in" half cages don't do anything in the areas that matter the most. A proper safety cage really requires the interior to be completely stripped before it can be installed, and then the interior put back in the best it can around the cage (which is kind of pointless at that point).

I think it's an all-or-nothing argument for "true safety." With that said, newer cars have quite a good amount of development when it comes to crashing, roll over protection, and crumple zones to protect the driver in as many different types of crash scenarios as possible.

[TopJimmy]

A bolt in cage is almost for show.

Why not take an older base model, strip it out, then have a full race cage fabricated and welded in? Then you're well protected.

[SYT_Shadow]

The GTS at 90k is pretty good value, as it comes with a half cage, more power, track worthy suspension and track worthy brakes.

However, you may be getting ahead of yourself. The less capable the car you start tracking is, the better and faster you will learn.
You've just started tracking and are thinking of getting a dedicated track car? I suggest you take a step back.

There are many levels of safety:
1)A neck restraint is a good safety upgrade. You can get a Simpson Hybrid Pro S that works with a 3pt belt. This is what most instructors use
2) Add track seats and QuickFit Pros. Cobra Nogaro is specifically homologated to work with the QuickFit Pro that accepts a neck restraint system. The belts clip in/out in around 20 seconds.
3) Add track seats, 6 point harnesses and harness bar, like Brey Krause.
4) Add track seats, 6 point harnesses and a half cage
5) Add track seats, 6 point harnesses and a full cage -- car is no longer road legal

Rollovers are quite rare at the track, so a half or full cage will help in a small subset of accidents. Neck restraints however help in almost every possible accident, so that should be a priority

Half cages can be put into M3s as well as M4s. There are plenty of reputable companies making bolt in rollbars/half cages.


Remember modern cars weigh a lot and are much stronger than older ones. Cars are tested for rollover. A stock M3, or any 3/4 series, has metal bracing under the roof in three spots which form a roll cage of sorts.

[TractionControlDelete]

The posters above have already given excellent responses but just wanted to add…

OP, since you've only done one HPDE day so far (and some scheduled) you might want to consider doing Autocross days until you have your safety setup dialed in. Autocross can teach you important driving skills, it's very fun, and the runs are done solo so other cars are largely out of the equation.

You can also get instructors to ride along to help you. At most you'll hit cones and maybe a barrier. Moreover, you can do an entire year of Autocross for less than the cost of a proper full cage.

Best of all, you'll be able to drive to the events and use the backseat (sans cage) to transport extra wheels/tires with use of the back doors for easier removal compared to the F82.

Just something to consider. Thanks for asking the question and drive safely.

[DocL]

Do you currently have a HANS device?

[drroc]

I have seen an M2 with a half cage do a flip. The A pillar on the passenger side collapsed quite a bit so obviously the half cage didn't really help that much. A race seat/harness and a hans device really helped the driver, and despite being sore, he was fine otherwise.

My suggestion is to get this thing first https://www.simpsonraceproducts.com/...mpson-hybrid-s "Simpson's Hybrid S model is currently the only Frontal Head Restraint proven effective for 3-point harnesses, and it is also FIA and SFI approved. Additionally, in a partnership with Detroit auto manufacturers, the Hybrid S is third party tested to FMVSS208."

[shaddy]

I think you are getting really ahead of yourself. The options that SYT_Shadow laid out are great, and I'd strongly recommend you stick to option 1 right now with a hybrid system. You need nothing more than that from a safety perspective + seat time to up your level of confidence. With more seat time you will gain more track awareness and be more comfortable with looking around/down track.

[TractionControlDelete]

Originally Posted by drroc

I have seen an M2 with a half cage do a flip. The A pillar on the passenger side collapsed quite a bit so obviously the half cage didn't really help that much. A race seat/harness and a hans device really helped the driver, and despite being sore, he was fine otherwise.

My suggestion is to get this thing first https://www.simpsonraceproducts.com/...mpson-hybrid-s "Simpson's Hybrid S model is currently the only Frontal Head Restraint proven effective for 3-point harnesses, and it is also FIA and SFI approved. Additionally, in a partnership with Detroit auto manufacturers, the Hybrid S is third party tested to FMVSS208."

+1

I have this system in my R53 Mini Cooper S. Fortunately, I haven't needed to test it personally from a collision.

Also, the car is solid:

[Montaver]

The f8x platform is very sturdy in a rollover, there are numerous videos out there.

The crash is around 3 mins, at about 4 mins it shows the aftermath.

If safety is your absolute priority you need a dedicated track car with a welded cage and automatic fire suppression system. You also need to be wearing the appropriate gear (HANS, fire suit, gloves, etc. etc.). However unless you are wheel to wheel racing, there are other levels of safety in between which are within most peoples comfort level for DE. Having a full harness setup is the biggest difference in my opinion, as it will enable you to focus on 100% driving the car not bracing your body which ultimately makes you less likely to crash in the first place.

[NYG]

So here's the basic truth to all this. What happens during a crash is a multi-variable mechanism that has boundary conditions.

Your car from the factory is EXTREMELY safe and the safety mechanism of the vehicle's performance is determined by the fact that your body accelerates/decelerates relative but separate from the vehicle and that you will dissipate that energy with airbags. Your safety depends on eliminating/dissipating as much energy as possible from the vehicle to your body. This all starts with the deformation/rupture of structural components on the vehicle.

The job of a cage (aside from providing some overall rigidity to the vehicle) is to protect a driver who is essentially LOCKED into his race seat with no airbags and no room to move. That's also where the hans device is very important. If you can't move in your race seat, your head can whiplash.

People confuse this stuff all the time and end up putting themselves in more dangerous conditions than they were initially. A cage does not automatically make you safer.

If you're tracking a modern street vehicle, leave it alone and wear standard safety equipment. If you want to turn it into a pure track car then you should do everything. Harness -> Full Cage -> Hans -> etc...

Also bolts and welds are both equally capable of providing support points of adequate stiffness. Welds provide more strength at the cost of ductility and frame embrittlement (weld/base metal rupture). That means whatever ductile material your frame is made out of suddenly behaves similar to glass instead of plastic.

[Theruleslawyer]

I think you are getting way ahead of yourself. You aren't even driving without an instructor yet. Your car is more than safe enough at the pace you will be doing for awhile.

As others have mentioned safety devices are a system. Either stick to the stock system or go all in. That means you end up with a dedicated track car. It will no longer be safe to drive on the street without a helmet.

If i were worried about it and had space Id just go buy a used prepped car. Plenty of stuff out there from various spec series. I keep toying with the idea of a used spec Miata. It would be way cheaper on consumables and much less of a hit if I do wad it up. Just make sure you get it teched at a race shop that can validate the safety gear.

[sly1types]

Full cages are really meant for wheel to wheel like others have said.

One thing i didn't see mentioned is what track are you at. The new Ozarks track is the Nurburgring of the Americas. But if you are on more complex dangerous track like the Ozarks you dial it back a little bit. I have only been to the Ozarks once (it was amazing!), but it won't be a track i drive 10/10ths at unless i have a race seats/hans/bolt in SSR 4pt or really a full cage...

I think either you do nothing or do seats/hans/cage. These cars are very safe from the factory. I saw a guy with a M4 hit a wall at 80+ and walk away.

[bimmerboyE92]

Originally Posted by rsyring

I bought a F80 M3 in May b/c I wanted to start doing HPDE track events. I've done a few events now, really like it, and have signed up for another handful of events before the end of the season. My last event was with Chin at the Ozarks, MO track and the instructor said I did really well and should be able to "graduate" to solo at my next event. (baby steps)

This past event was the first time I was at a Chin event and they emphasized safety more than the previous events I went to. I had been thinking about this anyway and planning to get my own helmet (was renting) and Hans device. Then I realized you can't use a Hans device without a cage or harness bar, so had started to look into cages and if that was "necessary" for my level at HPDE events. I've read some people who say they'd never get into a car at a track without a six-point harness and half cage. But then my instructor at this last event just used a hybrid neck restraint and didn't have a cage in her M2 and she had been doing this for a number of years.

Then, on my last lap at this past event, I came around a corner and there was a car that had recently passed me stalled on the track and pointed right at me. Thankfully on the opposite side of the track from my line. I think that solidified for me the reality that it's not just my driving that matters. Things will happen that are out of my control and I should be as prepared as I can be from a safety perspective.

So I decided I was going to put a half cage in my M3 but then realized doing that and keeping it as a DD would be silly. No sense putting a cage into a four-door vehicle. Trade the M3 in and get an M4, then put the cage in.

But then I started looking into cages that can be put into an F82 and found some "bolt-in" ones. I also found people in the forums who said it was pointless to do that, the installation method isn't strong enough to hold up when needed (the legs can just push through the floor pan).

I started looking for a more reputable opinion on putting a cage in an M2 and came across: https://www.roadandtrack.com/car-cul...ur-street-car/ That seemed like a reasonable perspective and I came away thinking I didn't want to be responsible for finding the right fabricator, with the right welding knowledge, to put a cage in my car and then "hope" that it was done right with proper engineering knowledge b/c there's no way to test something like that.

At that point I was pretty overwhelmed. I've committed to my wife to make this new hobby as safe as I can reasonably make it. I even started to look into E92 track builds where the cage was already installed but most of the ones I found were just bolt ins. I found one actual race car that looked like it had all the right safety equipment (and lots of other stuff that would be very overkill at my skill level and usage) but it was $135K!

I finally punted and put some money down on a M4 GTS. But at $92K the expense of this hobby is starting to get out of hand. I found a 2019 F82 that I like for $58K, and I'm sure I could find someone somewhere to put a half-cage in for $10K (?), but I'm still concerned I have no idea of they've done it right. At least with the GTS, presumably, BMW engineers that understand track dynamics and safety have evaluated and approved the cage that is installed by the factory. But at a $25K premium, I'd like to find another sufficient option.

I know this might seem like just an excuse to buy a GTS, but I'd really rather have a less expensive vehicle. Cheaper insurance, not as concerned about damage, etc.

So, just looking for advice on how to think through these things. Complete the GTS purchase and drive on? Or are there more economical options for making an F82 safer with the same level of confidence I can have with the GTS?

Thanks in advance.

I'm in Louisville! 1/2 cage for $10k??? WTF? IND... https://f80.bimmerpost.com/forums/sh....php?t=1165816

But, paid less than $2k for my McMahan half cage.

If you're going to spend 6 digits on a track car... make it a P-car.

[heyyouduh]

I think you should stay with OEM 3pt belt set up and use a hybrid Hans device for additional safety until you're sure you want a race car.

[phefner]

Was at AutoBahn CC on Monday. We had a car hit a barrier, somersault, roll, and come to a stop on its side. Hood didn't get crushed and driver was pulled out and walked to the waiting EMS vehicle. No cage. I'm in the camp of many others, hold on the seats and cage, get the Hybrid Hans. Simpson has some great videos that outlines how each type of Hans works. I'd also invest in a fire suit. Those you can get now.

But no matter what we do, even a fully built car with seats and cage won't protect you from everything. A driver lost his life at BlackHawk Farms a couple of weekends back running in a Chicago Region SCCA Sprint, when his car left the racetrack and hit a tree.

We do this at our own peril.

[LuvMyE92]

Originally Posted by phefner

We do this at our own peril.

Gawd, ain't that the truth!

The video above is why I stopped doing in-car instruction. I've crashed three times at the track, once as a student and twice as an instructor. I was injured in the first and third events. Minor injuries, but still, it hurts and in one case took years for full recovery.

I'll add that I've seen a lot of cars crash, and flip, and the BMWs generally do very well. Which is why I still drive a BMW.