Feasibility of 4pt rollbar and racing seats for dual duty car

[calubi]

How feasible is it to install a 4pt rollbar with race seats and still keep the ability to street the car occasionally? I'm thinking of a setup where the roll bar and race seats stay in the car, with a 6pt harness used on track and the stock 3pt belts used on the street. I've read a lot about the dangers of using cages on the street, but I'm not clear on whether that danger is significantly reduced if using a 4pt rollbar instead of a full cage, assuming fixed-back seats.

The intended track usage would be HPDE, no w2w racing or competitive time trials.

Is anyone here running such a setup for a weekend track car that can still be driven on the street for fun (not daily)?

[FormulaMMM]

Based upon your intended uses, what about this sort of setup instead https://www.bimmerworld.com/Safety-R...-1-Series.html



Rollbar aside, you'll likely struggle to achieve proper 3 pt safety in combination with 6 pt and buckets. Aside from the OE GTS seats, I've not seen an example of 3 pt properly integrated. They're all a safety compromise (in favor of 6 pt use on track).



For street + track in my E90 I wanted to combine those Schroth 4 pt harnesses with BMW Performance seats or Sportster CS, but never got there. Believe that would have been pretty ideal.

[kyrix1st]

Once bucket, always bucket.

I feel uncomfortable driving in normal seats because my body sways too much in corners and it's more difficult to feel the rear end movement.

[calubi]

I thought the schroth quick fit 4pt was not approved for f8x applications. Did that change?

[calubi]

Originally Posted by kyrix1st

Once bucket, always bucket.

I feel uncomfortable driving in normal seats because my body sways too much in corners and it's more difficult to feel the rear end movement.

Can you use 3pt belts on the street with that setup?

[FormulaMMM]

Originally Posted by calubi

Can you use 3pt belts on the street with that setup?

You can see the 3 pt buckle peeking up over the inboard side of the bucket. And while I agree with his sentiments about bucket + 6 pt being optimum for performance driving, that 3 pt setup is not "up to standards" for regular street use. Contrast that with the GTS pic above with the 3 pt buckle cutout in the seat.

I say that with my 3 pt setup being much the same type of compromise (below). To each their own on risk tolerance. I do very limited street driving with the 3 pt. Basically to/from the gas station during track days.



The first pic I posted is an M4 + Recaro Sporster CS (I think) + Schroth. Looks compatible. The reason it wouldn't be compatible with stock F8X seats is nowhere for the shoulder harnesses to pass through.

[calubi]

Ah, sorry, missed it hiding behind the seat side looking at the pictures on my phone.

So it sounds like the trick is selecting a seat that allows proper alignment of the 3pt belts? Does such a seat exist? How about the Cobra Nogaro with the BK mounts and OEM sliders, retaining the stock 3pt mounting locations that move with the seat?

Assuming this can be sorted, would the 4pt rollbar be a huge concern for occasional street driving?

[sc_tr0jan_m3]

once you go with a fixed back and some form of a roll bar, you really lose the flexibility and utility of the car. it's a slippery slope and a hard one to back away from.

have you tried just using a cg lock on a 3 point to reduce the sliding?

[fanatic1]

Originally Posted by FormulaMMM

You can see the 3 pt buckle peeking up over the inboard side of the bucket. And while I agree with his sentiments about bucket + 6 pt being optimum for performance driving, that 3 pt setup is not "up to standards" for regular street use. Contrast that with the GTS pic above with the 3 pt buckle cutout in the seat.

I say that with my 3 pt setup being much the same type of compromise (below). To each their own on risk tolerance. I do very limited street driving with the 3 pt. Basically to/from the gas station during track days.



The first pic I posted is an M4 + Recaro Sporster CS (I think) + Schroth. Looks compatible. The reason it wouldn't be compatible with stock F8X seats is nowhere for the shoulder harnesses to pass through.

Image above from EAS looks familiar, it works fine, but a fixed back seat would be better at the track. The recline feature is the reason for the Recaro sportster in my case. And yes, the stock M4 seats have no pass-through (big miss BMW) for the upper belts.

[nicknaz]

Originally Posted by kyrix1st

Once bucket, always bucket.

I feel uncomfortable driving in normal seats because my body sways too much in corners and it's more difficult to feel the rear end movement.

Edit: is that your car? Are you sure you have improved your safety? Best of luck and please stay safe

OP, just my $0.02 don’t mix and match. Modify the car so it will pass club race safety tech or use the stock safety gear. Just because someone has done it doesn’t mean it’s safe, so read the rules for club racing and ask yourself why those rules are there and what are the consequences if you half a$$ and you stuff it

[kyrix1st]

Originally Posted by nicknaz

Edit: is that your car? Are you sure you have improved your safety? Best of luck and please stay safe

OP, just my $0.02 don’t mix and match. Modify the car so it will pass club race safety tech or use the stock safety gear. Just because someone has done it doesn’t mean it’s safe, so read the rules for club racing and ask yourself why those rules are there and what are the consequences if you half a$$ and you stuff it

Yes it is, back in Japan. This passes regional MOT as is, so I think it should be fine. I generally don't use 3pt, although I guess I could move the buckle inside to make it truly road compliant.
If I am being nit-picky about track usage, the upper section of 6pt should come at 15 deg or so according to FIA rule book (gotta check the angle) for track safety. All else is in alignment with Suzuka regulations.

[calubi]

I have no intention to half ass anything, I'm just trying to get a handle on what's feasible and learn what my options are. For track use, if I were to go non-stock, the setup I would go with would include the roll bar, fixed back seat, and harness; no half way measures. Everything by the rule book.

My question is really whether such a setup could also be used for occasional street use. Not daily use, likely not even weekly, just the occasional drive on a nice day or after some maintenance work to ensure the health of the car. And for that I would need to retain the ability to use the stock 3pt belts.

What I would like to know is:

1. Are there options for fixed-back race seats that allow for proper usage of 3pt belts?

2. Is the use of a 4pt roll bar (let's take the StudioRSR unit for arguments sake) on the street, with the fixed back seat from (1) above, a complete death trap, or is the risk low due to all of the bars being behind the fixed back seat?

Thanks for the answers! Just trying to learn as much as I can here!

[FormulaMMM]

Originally Posted by calubi

My question is really whether such a setup could also be used for occasional street use. Not daily use, likely not even weekly, just the occasional drive on a nice day or after some maintenance work to ensure the health of the car. And for that I would need to retain the ability to use the stock 3pt belts.

What I would like to know is:

1. Are there options for fixed-back race seats that allow for proper usage of 3pt belts?

Here's a perspective on why the Nogaro provides at least better than avg bucket + 3 pt integration https://www.2addicts.com/forums/show....php?t=1520689

"Proper?" No. For that you'd need the factory solution like the GTS picture above.

Everything outside of that is subjective safety and I'm not aware of any two people here with the same race seat setups, i.e., there is no clear aftermarket bucket solution to achieve optimum street (3 pt) & track (6 pt) safety.

You're talking about adding a roll cage just behind your head in combo with a substandard 3 pt setup in an aftermarket bucket.

In a severe crash can your body/head move around in enough radius to impact the bar? Without a doubt, so I see no way around that being a legit added hazard during street use.

[SYT_Shadow]

I would get the BK harness bar that allows you to quickly remove it, does not include permanent modifications and allows 6pt belts, hans device and fixed back seats.

Huge difference vs stock

[FormulaMMM]

Originally Posted by SYT_Shadow

I would get the BK harness bar that allows you to quickly remove it, does not include permanent modifications and allows 6pt belts, hans device and fixed back seats.

Huge difference vs stock

Nice. I've only bounced around their F82 section so never saw this.

[SYT_Shadow]

Originally Posted by FormulaMMM

Nice. I've only bounced around their F82 section so never saw this.

It's what I run in the F80CS. Super solid, easy to remove, no permanent modifications, can be used with the rear seat installed...

It's fantastic

[FormulaMMM]

Originally Posted by SYT_Shadow

It's what I run in the F80CS. Super solid, easy to remove, no permanent modifications, can be used with the rear seat installed...

It's fantastic

One more reason the sedans of each gen are the ones to have.

[SYT_Shadow]

Originally Posted by FormulaMMM

One more reason the sedans of each gen are the ones to have.

it exists for the couples as well, thank god!

[calubi]

Aren't the harness bars (without roll over protection) dangerous on track in case of a roll over? The 6 pt harness and seat would not allow you to fold over if the roof caves in a bit, like the 3pt and stock seats would.

[SYT_Shadow]

Originally Posted by calubi

Aren't the harness bars (without roll over protection) dangerous on track in case of a roll over? The 6 pt harness and seat would not allow you to fold over if the roof caves in a bit, like the 3pt and stock seats would.

That has been thoroughly debunked through Scroth's whitepaper on accidents

It's better to have a cage, but the harness bar and 6pt is safer than stock seats+3pts. Having a cage for the street is a no-no, so for a dual duty car this is the best option

[calubi]

Originally Posted by SYT_Shadow

That has been thoroughly debunked through Scroth's whitepaper on accidents

It's better to have a cage, but the harness bar and 6pt is safer than stock seats+3pts. Having a cage for the street is a no-no, so for a dual duty car this is the best option

Do you happen to have a copy of the whitepaper? I've found a few links posted in other threads, but they're all dead links.

[SYT_Shadow]

Originally Posted by calubi

Do you happen to have a copy of the whitepaper? I've found a few links posted in other threads, but they're all dead links.

These are the summary slides








I have a copy of the whitepaper but it's huge, like 46mb.