4 Point Harness & "Racing" Seat

Anonymous · June 7, 2003, 16:25

Has anyone fitted a 4 point harness and a good seat to their 2?

thanks in advance s:)

s:)

mph · June 8, 2003, 11:52

Quote from: "tb799"Has anyone fitted a 4 point harness and a good seat to their 2?

Uh, not yet s8)

s8)

There is much speculation (though little fact) over the safety of 4-point and submarining. As such a 5- or 6-point is very little more, both in terms of cost and hassle of fitting and that's what I'd recommend. There is further speculation that in the event of a roll-over, without a roll-bar (noting the difference to style-bar) you could be in a worse situation if strapped in with a full harness when compared with a stock 3-point system.

UK regulations for MOT purposes state that you need a push button mechanism to release the seat-belt. Between that and hassle of day-to-day short trips, many suggest keeping your existing seatbelts in place.

Back to the speculation again, there has been some comment over whether the airbags would fire (particularly the passenger bag) if the ECU didn't think your seatbelt was fitted. The I am highly skeptial about as there is no mention in the workshop manuals, and indeed, US safety regulations state that the car should provide maximum protection even when the passengers do not wear seatbelts.

There are no off-the-shelf subframes for seats yet, so some fabrication will be required to adapt a universal frame. The two lower mounts appear adequate for holding your additional point, though you'll need a spreader plate if you take up the recommendation of fitting a 5th or 6th point.

That leaves the shoulder mounting, and the only practical place for that (if you don't intend on permanently removing the soft-top is the cross member that goes between the two upper seat belt mounts. I am wary that this is adequate strength as it hasn't been designed for forces other than compression and tension. Of course, if fitting a proper roll-bar, a suitable mounting mechanism could easily be added to the device.

Keep us informed of what you find out!

s:idea: :idea: s:idea: At all times, I suggest getting expert opinion regarding this modification, and if possible from multiple sources. Never forget, your life could depend on it s:!: :!: s:!:

Anonymous · June 8, 2003, 15:05

Martin

thanks for the info

Terry

markiii · June 8, 2003, 16:39

Moved to Performance Related Forum.

kanujunkie · July 26, 2005, 15:35

just bumping this back to the top, has anyone else fitted these since this was last talked about, i may talk to someone like sparco if not, but would definatly like 4/5 point harness for appearance as well as track days

Peter Laborne · July 31, 2005, 19:59

I remember talking to Safety Devices about a five-point belt years ago. They had come up with a new system that had g-force meters and electronics built in so that when you were driving normally, the restraint behaved like a seat belt allowing you to fiddle with knobs, change a cd etc, yet when you put your foot down and started to give it some (or take it to a track) the restraint would pull you back into the seat and lock in position, behaving like a normal racing harness.

However, there were a few problems:
1) They satated that a racing harness/restraint/seat belt should only be mounted directly on the chassis or a roll cage
2) They had not developed a roll cage for the Roadster yet

However, they were going to let me be a guinnee pig. But I thought against taking them up on the offer after reading more on restraints and moreover, the ideal mounting point angles. Namely:
1) The lap sections need to be at an angle of 45deg from the point at which they cross the seat
2) The shoulder straps need to be at an angle of 30deg from the horizontal

Mounting it at the wrong angles can cause the seat to break in a crash or roll-over.

So does anyone else want to be a guinnee pig?

kanujunkie · July 31, 2005, 20:06

would do but i'm not interested in all those fancy gimiks on a seat belt, i still dont understand why a simple c of g lock cant be fitted to some shoulder straps and a fixed lap strap, aircraft have this design, why cant cars

Chris · August 1, 2005, 13:32

i seem to recall someone on here (slacey?) found a little 'widget' that fitted on a normal seatbelt and locked it in place, giving a poor mans harness effect...

Bongo · August 1, 2005, 13:44

m http://www.cg-lock.com/ m

Chris · August 1, 2005, 13:49

yep, that'd be the one! s:wink: :wink: s:wink:

Tem · August 1, 2005, 14:31

Go for it, they are great! I have two s8)

s8)

kanujunkie · August 1, 2005, 20:11

i just fancy the look of the 4 point harness's that was all, dont think the CG lockwould have the same effect

Anonymous · August 1, 2005, 23:50

you will need to get extra bracing added to the existing cross member inside the cubby, this is quite exstensive welding but the only really safe way to strap yourself in without a full roll cage (roll cages are available in the US if your that way inclined)

kanujunkie · August 1, 2005, 23:56

Quote from: "perry190"you will need to get extra bracing added to the existing cross member inside the cubby, this is quite exstensive welding but the only really safe way to strap yourself in without a full roll cage (roll cages are available in the US if your that way inclined)

cheers Perry, guess this aint a possability for me as i need the storage space, i still take out the speaker panel i bought from you when i go away let alone putting a bar inside, guess i should thin again, i've got some big plans for appearance set off by you, just got to get the money together