Trackday Harness
Author
Discussion

Kecky

Original Poster:

95 posts

202 months

Thursday 16th July 2009
quotequote all
Has anybody fitted a 4 point harness in a classic shape impreza/or other car for that matter for trackdays.
The shop i bought the harness from told me one of the rear fixings could go to one of the existing rear seatbelt mounts and then drill a whole for the other one.
But....
The garage fitting them reckons they won't reach that far back.
Has anybody firtted a harness in this way????

mat205125

17,790 posts

237 months

Thursday 16th July 2009
quotequote all
Forgetting the length issue, by drill a hole for the other one, I assume you mean that there will be a large enough spreader plate fitted (ideally welded) the other side of the eye-bolt fixing, and not just a normal nut'n'washer.

Kecky

Original Poster:

95 posts

202 months

Thursday 16th July 2009
quotequote all
mat205125 said:
Forgetting the length issue, by drill a hole for the other one, I assume you mean that there will be a large enough spreader plate fitted (ideally welded) the other side of the eye-bolt fixing, and not just a normal nut'n'washer.
Of course......they came with a 50mm square spreader plate with a nut welded to the back.
The fixing is not the issue, it's the actual length of straps that have been questioned.

mrmr96

13,736 posts

228 months

Thursday 16th July 2009
quotequote all
I have an Evo 8 which is similar in shape/style to your scooby. I have attached the shoulder straps to an eyebolt on the parcel shelf. Basically I bought some eye bolts and removed the cardboard cover from the parcel shelf. This gave me access to the bolt which holds the inertia reel over the shoulder of the rear seat passenger. Replace this bolt with an eye bolt and clip the drivers shoulder harness strap(s) to this. Repeat on the passenger side. I have then drilled holes in the cardboard parcel shelf and refitted it over the metal shelf so the bolts poke through. Looks nice and subtle.

Good things about this are:
- Uses OEM mounting points (so strong and don't require welding or cutting of metal)
- Hold the straps at the right angle (they are supposed to be no steeper than 21 degrees below horizontal.)
- Doesn't need a harness bar (so cheaper as avoids this cost and safer when carrying rear seat passengers)
- The drivers right shoulder strap goes straight back

Bad things:
- Straps need to be quite long
- If there's an intrusion into the rear of the car then it could pull on the straps. (This is a possibility. This is preferable to the near certainty that mounting at a steep angle, for example using the lap belt points from the rear seat, will cause spine compression in an forward impact.)
- The drivers left shoulder strap goes at a slight angle to reach the mounting point on the right shoulder of a rear seat passenger. (Could possibly improve this by using a 3 point as opposed to a 4 point.)

If my car was track dedicated then I'd get a cage or a harness bar. As it isn't I think using clip in/out eye bolts in the OEM points on the rear shelf is next best.)

HTH

ETA: I've done the above with Willans standard lenght 4 point harnesses, albeit at the limit of their adjustment.

Edited by mrmr96 on Thursday 16th July 16:15

Jamz

408 posts

217 months

Friday 17th July 2009
quotequote all
You shouldnt fit harnesses to your car unless you have a roll cage fitted!



Harnesses are supposed to mount to your roll cage, and be no lower then 10degrees from your sholder.

Fitting these witout a roll cage, and if you are in a crash, you will crush your spine and be in a wheelchair for the rest of your life.

timarnold

515 posts

266 months

Friday 17th July 2009
quotequote all
Jamz said:
You shouldnt fit harnesses to your car unless you have a roll cage fitted!

Harnesses are supposed to mount to your roll cage, and be no lower then 10degrees from your sholder.

Fitting these witout a roll cage, and if you are in a crash, you will crush your spine and be in a wheelchair for the rest of your life.
I was just about to post pretty much the same thing. Absolutely correct, don't fit a full harness without a roll cage!

Why are you fitting a harness? For the safety aspect (see above)? Or to stop you sliding around the seat during high-speed braking and cornering? If it's the latter there is a very effective and less expensive alternative, the CG-Lock; or click this link to get it at a discounted offer price: CG-Lock-TA discount.

It only locks the lap strap of an inertia reel seat belt; securing you in place and preventing you from sliding around or 'submarining'under braking; but it leaves the shoulder strap free to reel, so if the roof comes down to say hello you can get out of the way! ;-)

fergus

6,430 posts

299 months

Friday 17th July 2009
quotequote all
mrmr96 said:
I have attached the shoulder straps to an eyebolt on the parcel shelf. Basically I bought some eye bolts and removed the cardboard cover from the parcel shelf. This gave me access to the bolt which holds the inertia reel over the shoulder of the rear seat passenger. Replace this bolt with an eye bolt and clip the drivers shoulder harness strap(s) to this. Repeat on the passenger side. I have then drilled holes in the cardboard parcel shelf and refitted it over the metal shelf so the bolts poke through. Looks nice and subtle.


If my car was track dedicated then I'd get a cage or a harness bar. As it isn't I think using clip in/out eye bolts in the OEM points on the rear shelf is next best.)
The eye botls should be mounted in tension, not shear, so fitting them to the parcel shelf puts them in their weakest possible plane.... The way the std bolt is used in its original application is a lot safer as there is a LOT less load around the shank of the bolt than would the case with a wrongly oriented eye bolt in the event of a frontal crash. You may want to ensure there is a plate/large washer behind the parcel shelf to stop the eye bolt ripping out of the parcel shelf due to it's weakened orientation....

mrmr96

13,736 posts

228 months

Friday 17th July 2009
quotequote all
Jamz said:
Fitting these witout a roll cage, and if you are in a crash, you will crush your spine
Please explain how.

fergus

6,430 posts

299 months

Friday 17th July 2009
quotequote all
mrmr96 said:
Jamz said:
Fitting these witout a roll cage, and if you are in a crash, you will crush your spine
Please explain how.
I think he means that when most people fit harnesses w/o a cage, they tend to fix the shoulder belt mounts to the base of the rear firewall, which is way to acute an angle and can crush the back of a std seat.

mrmr96

13,736 posts

228 months

Friday 17th July 2009
quotequote all
fergus said:
mrmr96 said:
Jamz said:
Fitting these witout a roll cage, and if you are in a crash, you will crush your spine
Please explain how.
I think he means that when most people fit harnesses w/o a cage, they tend to fix the shoulder belt mounts to the base of the rear firewall, which is way to acute an angle and can crush the back of a std seat.
In which case I agree - as I put that in my original post. The way I have described fitting mine will not have this problem. (Instead you have the possible problem of roofline deformation, and you can't so easily 'duck' out of the way.)

timarnold

515 posts

266 months

Friday 17th July 2009
quotequote all
mrmr96 said:
Jamz said:
Fitting these witout a roll cage, and if you are in a crash, you will crush your spine
Please explain how.
If you are firmly strapped into a full harness your entire body from the neck down is not going to move very far if at all during an accident, but your head and neck are free to move. In an accident where the car comes down heavily upside-down and doesn't have a roll cage, the roof of the car can deform catastrophically, coming 'down' on your head. Your torso is locked rigidly in place by the harness, meaning there is little or no give, or ability to move, to allow your head and neck room to be pushed out of the way of the rapidly descending roof. Your head and neck become sandwiched between the roof and your own body - something has to give way and it will be your neck! A roll cage will prevent or at least reduce the amount of deformation of the roof, thereby protecting your head and neck. That's why it's called a roll cage!

fergus

6,430 posts

299 months

Friday 17th July 2009
quotequote all
mrmr96 said:
fergus said:
mrmr96 said:
Jamz said:
Fitting these witout a roll cage, and if you are in a crash, you will crush your spine
Please explain how.
I think he means that when most people fit harnesses w/o a cage, they tend to fix the shoulder belt mounts to the base of the rear firewall, which is way to acute an angle and can crush the back of a std seat.
In which case I agree - as I put that in my original post. The way I have described fitting mine will not have this problem. (Instead you have the possible problem of roofline deformation, and you can't so easily 'duck' out of the way.)
It's quite hard to move even when an inertia reel belt locks. In the time it takes a car to roll, believe me, 99% of people wouldn't be thinking about trying to duck, or have time!

mrmr96

13,736 posts

228 months

Friday 17th July 2009
quotequote all
I think it's clear by now that Jamz statement was very sweeping. And
i) Would an inertia reel belt be any better if the roof comes in, and
ii) What % of accidents will this happen in any way?

The way I look at it is to consider what types of accident I might have and which type is most likely. I will then prepare myself for the most likley type of crash.

I believe that the most likely type of crash I will have in my Evo is driving into something and hitting it primarily with the front of the car. In this instance the harness will be better than the inertia reel belt. (PS, FWIW I wear a helmet and neck brace on track so if/when my head is thrown forward there is some support to prevent my head flailing about.)

fergus

6,430 posts

299 months

Friday 17th July 2009
quotequote all
mrmr96 said:
I think it's clear by now that Jamz statement was very sweeping. And
i) Would an inertia reel belt be any better if the roof comes in, and
ii) What % of accidents will this happen in any way?

The way I look at it is to consider what types of accident I might have and which type is most likely. I will then prepare myself for the most likley type of crash.

I believe that the most likely type of crash I will have in my Evo is driving into something and hitting it primarily with the front of the car. In this instance the harness will be better than the inertia reel belt. (PS, FWIW I wear a helmet and neck brace on track so if/when my head is thrown forward there is some support to prevent my head flailing about.)
Unless it's a HANS type brace, a karting foam 'collar' offers very little protection, and can actually increase soft tissue damage if the torso is fixed(unlike a kart driver).....

timarnold

515 posts

266 months

Friday 17th July 2009
quotequote all
mrmr96 said:
The way I look at it is to consider what types of accident I might have and which type is most likely. I will then prepare myself for the most likley type of crash.

I believe that the most likely type of crash I will have in my Evo is driving into something and hitting it primarily with the front of the car. In this instance the harness will be better than the inertia reel belt...
You can't second guess what type of accident you're most likely to have or how your car will be orientated during or after an accident!

At Oulton Park many Evo's (you could bet on it and win 50% of the time) end up in the gravel at Druids - mainly because Evo drivers tend to rely on electronics rather than talent to keep them on the road and the electronics can't always cope with what's expected of them - and a large percentage of them end upon their roof because they have gone in sideways, the wheels have dug in, and the car has flipped!

fergus

6,430 posts

299 months

Friday 17th July 2009
quotequote all
timarnold said:
....mainly because Evo drivers tend to rely on electronics rather than talent to keep them on the road and the electronics can't always cope with what's expected of them...
hehethumbup

but it's got 9 million hp mate.....

mrmr96

13,736 posts

228 months

Friday 17th July 2009
quotequote all
timarnold said:
mrmr96 said:
The way I look at it is to consider what types of accident I might have and which type is most likely. I will then prepare myself for the most likley type of crash.

I believe that the most likely type of crash I will have in my Evo is driving into something and hitting it primarily with the front of the car. In this instance the harness will be better than the inertia reel belt...
You can't second guess what type of accident you're most likely to have or how your car will be orientated during or after an accident!

At Oulton Park many Evo's (you could bet on it and win 50% of the time) end up in the gravel at Druids - mainly because Evo drivers tend to rely on electronics rather than talent to keep them on the road and the electronics can't always cope with what's expected of them - and a large percentage of them end upon their roof because they have gone in sideways, the wheels have dug in, and the car has flipped!
Regards "Evo Drivers": I do not intend to enter into a debate about owners/drivers of particular types of car based on sweeping generalisations.

Regards the type of crash: Please follow this train of though with me and tell me where you think it goes wrong:
- Main danger in a crash is hitting things inside the car (dash board/steering wheel)
- Harness will keep you in your seat better than a 3 point inertia reel belt
- Harnesses are best used with a roll cage
- If you fit a cage you need a helmet
- You can't really drive daily on the road in a helmet in a saloon car
- So if you want to increase your safety on the road, what do you do? I chose to "seccond guess" the type of crash I think is most likely and fit a harness, but no cage for the above reasons.

Please tell me what you would do if you were, for example, on a trip to the Isle of Man (as I was when I first bought the harnesses) and expecting to drive pretty fast on the country roads? Would you leave it to the OEM 3 point inertia reel or try to upgade some how, and if so then how?


fergus

6,430 posts

299 months

Friday 17th July 2009
quotequote all
mrmr96 said:
Would you leave it to the OEM 3 point inertia reel or try to upgade some how, and if so then how?
One of the devices that locks the inertia reel in place, effectively pre-tensioning it ("CG-lock"). Best real world compromise for road biased driving.

mrmr96

13,736 posts

228 months

Friday 17th July 2009
quotequote all
fergus said:
mrmr96 said:
Would you leave it to the OEM 3 point inertia reel or try to upgade some how, and if so then how?
One of the devices that locks the inertia reel in place, effectively pre-tensioning it ("CG-lock"). Best real world compromise for road biased driving.
I have one of those and I must say it's not bad in terms of a relativly cheap and easy to fit driver aid. However it is not a safety device and therefore not a 'compromise' at all as my question was how to improve safety.

fergus

6,430 posts

299 months

Friday 17th July 2009
quotequote all
mrmr96 said:
fergus said:
mrmr96 said:
Would you leave it to the OEM 3 point inertia reel or try to upgade some how, and if so then how?
One of the devices that locks the inertia reel in place, effectively pre-tensioning it ("CG-lock"). Best real world compromise for road biased driving.
I have one of those and I must say it's not bad in terms of a relativly cheap and easy to fit driver aid. However it is not a safety device and therefore not a 'compromise' at all as my question was how to improve safety.
It's a safety device in that it does act as a pre tensioner, over and above whatever may be built into to your car.

I think you either have to 'compromise' or go for a harness and accept that there are some limitations with a harness in a road car.