# 4 point harness in roadster



## TT/DSM (Nov 19, 2012)

So I'm wondering the options of install methods for four point harnesses in a roadster. I saw in another forum that they made a bracket with the stock roll hoops. Is this safe? What are the safe ways of installation?


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## idwurks (Oct 25, 2003)

You should check out a rear seat delete along with the chassis brace back there!


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## Marcus_Aurelius (Mar 1, 2012)

idwurks said:


> You should check out a rear seat delete along with the chassis brace back there!


Roadster+ rear seats = fail


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## idwurks (Oct 25, 2003)

Marcus_Aurelius said:


> Roadster+ rear seats = fail


Yes that was clearly me failing :banghead: Oh well.


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## Marcus_Aurelius (Mar 1, 2012)

OP, I'll see if I can find some pics of my setup for you. I used a single rear anchored 4 point safety belt (do not use a 5 point belt in a car without a cage). I mounted the single anchor point between the two bars of the driver side roll hoop. I used a long grade 8 bolt that goes through drilled holes inside the entire aluminum bulkhead (this thing is at least 4" thick). I secured it at the bottom with a lock-washer and a nut. 

This was the most secure approach in my opinion. I too, thought about integrating a harness bar into the roll hoop... but realized that I wouldn't want the component that holds the safety harness to be failing/deforming in a roll over (leaving me SOL with no restraints).


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## Imola_TT (Aug 21, 2011)

Marcus_Aurelius said:


> OP, I'll see if I can find some pics of my setup for you.


Would love to see this too, please.
Examples of harnesses, harness bars and/or cage in roadsters are hard to find!


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## TT/DSM (Nov 19, 2012)

Alright, pics of that sound great. I would have figured that attaching it to the stock roll hoops would completely compromise the belts safety if a crash did occur.


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## Marcus_Aurelius (Mar 1, 2012)

This is the only picture I can find right now . Under the plastic cover panel, there's an approximately 4" thick aluminum bulkhead that the roll hoops goes through. I drilled a hole through it and used a bolt that is long enough to show an inch of threads on the other side, then secured it with a nut and lock whasher.


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## Marcus_Aurelius (Mar 1, 2012)

This is what you want to drill through to secure the harness. It's the rectangular section in green that the hoops go through. :beer:


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## 20v master (May 7, 2009)

I was going to ask if that bulkhead looked like it would bolt in, but it doesn't look like the structure around the B pillars in a coupe would have the mounting points. I also looked up dealer price on that piece and it's $45 shy of $1K. Scratch that idea. :laugh:


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## Audiguy84 (Nov 14, 2006)

Why not just use the hoops, they were designed to protect the driver from a roll over, i'm sure there strong enough to use as a support


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## Marcus_Aurelius (Mar 1, 2012)

Audiguy84 said:


> Why not just use the hoops, they were designed to protect the driver from a roll over, i'm sure there strong enough to use as a support


How do you safely mount them to the hoops without welding another hotizontal bar? 

Have you also checked the thickness of the hoops? They are not necessarily welding friendly. 

The 3rd problem is actual safety in a roll over. If the hoops are failing/twisting, what would you anticipate will happen to the safety harness it's holding? 

The purpose of a safety harness is twofold, it has to hold you in place while driving and cornering, but it has to meet safety requirements too. I don't see any sanctioning bodies letting you pass inspection with some questionable hoop mounts for your safety harness. They are already strict as it is, with letting roadster on track, half-assing it is a sure way of not being able to track the car. My 2 cents!


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## 18T_BT (Sep 15, 2005)

Max, I thought for most SCCA events the harness has to be attached to the floor?


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## TT/DSM (Nov 19, 2012)

Ok, that sounds reasonable. Do you just bolt the lower points to the stock seatbelt mounts?


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## Marcus_Aurelius (Mar 1, 2012)

18T_BT said:


> Max, I thought for most SCCA events the harness has to be attached to the floor?


Harness to the floor (rear anchor point of the shoulder strap specifically) would actually be super dangerous and not pass inspection. There is only a 10* of safe angle range for the shoulder strap in relation to its anchor point. If you exceed this angle, going downward towards the floor, the belt would be using all the G-forces in an accident to crush down your shoulders and spine. The proper safe angle is illustrated below, and shows that the rear anchor point needs to be close to level with your shoulder height. 

In the Roadster, using the bulkhead as the rear anchor point, brings the shoulder strap right within the safe range with the stock seats and rails (aftermarket seats may need to be mounted lower than stock because of taller back section). It is to be noted that the stock seat have to be lowered all the way for it to work and be legal for SCCA.


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## Marcus_Aurelius (Mar 1, 2012)

TT/DSM said:


> Ok, that sounds reasonable. Do you just bolt the lower points to the stock seatbelt mounts?


Yes, the stock seatbelt points on the floor works out perfectly and lands in the proper range. Kind of amazing how it miraculously happen to fit like a glove in the roadster. :beer:


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## TT/DSM (Nov 19, 2012)

So this will be legal for SCCA? 
I'm planning on doing SCCA auto cross this summer and it would suck if they denied my because of the harness.


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## Marcus_Aurelius (Mar 1, 2012)

TT/DSM said:


> So this will be legal for SCCA?
> I'm planning on doing SCCA auto cross this summer and it would suck if they denied my because of the harness.


Yes Sir, it will pass no problem for autocross (a standard belt is the minimum requirement). However, if the harness is dangerously installed, they will not let you run with it at National tours, Pro-Solo, and road racing.


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## TT/DSM (Nov 19, 2012)

Ok thank you. That was a big help.


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## Marcus_Aurelius (Mar 1, 2012)

:beer::beer:


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## theswoleguy (Jan 25, 2006)

Hi, interested...

Sent from my DROID BIONIC using Tapatalk 2


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## 20v master (May 7, 2009)

theswoleguy said:


> Hi, interested...
> 
> Sent from my DROID BIONIC using Tapatalk 2


 I guess you're planning on keeping this TTQR for a while and not "just taking Mal around the block a few times." :laugh:


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## theswoleguy (Jan 25, 2006)

20v master said:


> I guess you're planning on keeping this TTQR for a while and not "just taking Mal around the block a few times." :laugh:


 Haven't decided, r car title is becoming difficult. This runs now. Needs work, kinda turtle shell cramped, but gokart fun at the same time.

Sent from my DROID BIONIC using Tapatalk 2


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## 20v master (May 7, 2009)

theswoleguy said:


> Haven't decided, r car title is becoming difficult. This runs now. Needs work, kinda turtle shell cramped, but gokart fun at the same time.


 You should try it in a coupe with a helmet on!


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## theswoleguy (Jan 25, 2006)

sounds worse i wonder what the inside difference is between hard top and the convertible top is like. 

def ****ing tiny, i never drove it with the top up till after it got tagged which was like 20 miles and a few days after it got running. would do neighborhood laps and drive to exhaust shop and what not... boy the first day i drove it top up i thought i was going to have a claustrophobic fit... 

how are you cars coming along ? are you 2.0T and 35R i cant remember what the GTi had?


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## 20v master (May 7, 2009)

Josh you are the king of turning threads into off topic personal discussions. :laugh: I need a new set of pistons and a front bumper, slowly collecting parts.


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## theswoleguy (Jan 25, 2006)

20v master said:


> Josh you are the king of turning threads into off topic personal discussions. :laugh: I need a new set of pistons and a front bumper, slowly collecting parts.


 lol what i thought the thread was closed-solved... 

OP sorry for derailing, incase you missed it, in a roadster drill through the alumn support behind the seats, use a long grade 8 bolt. The reasons for this location are as follows: 
1) see picture of stig in race suit buckled in 
2) roll over and or deceleration from impact = spinal compression 
3) roll supports will twist, contort and change other shapes during a roll over, you do not want to have yourself attached to this. 

Adam,


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## Rford71 (Sep 1, 2011)

Max, what harness are you using?


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## Marcus_Aurelius (Mar 1, 2012)

Rford71 said:


> Max, what harness are you using?


Hey Rob, I'm using an old school slightly modified DOT approved Schroth Rallye 3 harness. The newer version of my harness can be found here:
http://www.schrothracing.com/tuning/rallye/rallye-3


I highly recommend the DOT approved harnesses from Schroth, especially if you're going to use it in the streets. They make excellent harnesses with attachment and release mechanism that makes sense for street driven car. Having the DOT approval # stamped on the belt also helps greatly if you get pulled over. Below are some better pics of the attachment points I used to run with the factory crossmember/bulkhead piece still installed (I have new rear attachment points now):




































Left side floor attachment point (using OEM belt hole)












Right side attachment point (using RH rearward seat mount hole for the mounting hook)


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## Rford71 (Sep 1, 2011)

Thanks Max


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