Roll-over protection

[SLYDIT]

OK HOLD THE BOAT...

theres a few basic things that ned to be said before you get too carried away with roll bars...

*For road and CLUBSPORT use the bar DOES NOT need to be MSNZ approved. ONLY if you are doing circuit racing and gravel work. for sealed sprints/autocrosses/dual sprints any bar is ok as long as it is ok'd by the scrutineer as being sound.
Also it doesnt need to be certified from LVVT as most roll bars for mx's are behind the drivers seat and technically "not in the passenger compartment"

* the design of the bar has to be thought out very carefully with respect to three particular aspects....
1) most bars will interfere with the operation of the seatbelts. Removing the seatbelts and replacing them with harnesses requires a MSNZ bar and log book. So you want to keep your stock seatbelts in there.
If you use a "narrow" bar that allows stock seatbelts to be used then this may interfere with any harness straps that you may want to use.
If you use a "wide" bar then you need to delete your stock seatbelts OR bring the bar forward a bit which comes into the passenger compartment more and will obstruct your hard top latches on the sides.
2) the mx5 is perhaps the hardest car to get a bar into because of the natural height restriction of the top, and the fact that the soft/hard tops have different height/fore/aft measurements.
3) Also the mazda engineers very carefully managed to put blardy box sections all over that part of the car making a straight forward bolt in type cage that much harder.

thats why i suggest you have a really good look at current bars available and how they are designed to get around these challenges.
the brown davis bar design is very good s it allows the use of both stock belts AND harness straps, AND its CAMS approved which means its design has been approved by a motorsport authrity not too far from here meaning its not going to collapse on you due to some major design flaw

[zippy2]

if its just for clubsport stuff then anything goes really. if you want to do gravel or circuit racing with other cars you'll need a MSNZ spec bar.

if you do a bit of googling for "brown davis" or "hard dog" roll bars then you'll see what sort of bolt in bars will be ok for a bit of weekend fun.

In the wellington region most of the clack of course people will not allow a non (half or full) caged open top / soft top car to run in any event above motorkhana level. So no single car sprints, hill climbs or autocross. Although I have seen some people manage to convince the COC, but would not count on it.

And any cage (half or full) must be MSNZ approved with all the paper work in your log book.

My half cage, with harness bar was $600 - drive in drive out, - including all the paper work, log book - powder coating etc.

[WideOpenThrottle]

Hi Zippy....$600 sounds good value be nice if i could get a deal like that around here!

[SLYDIT]

the COC's are obviously not aware of what the regs actually say. for clubsport (basic) you dont need a MSNZ bar. several of my mates run "home made" bolt in bars thier cars on clubsport events with no issues at all from the clark of the course...i run my car with the hard top on just so it doesnt look as dodgy to the COC.

there is obviously a whole heap of grey areas and bars that have been certed that "technically" don't actually comply.
the problem is that you never know what you are going to get in terms of scrutineers etc.
i have seen SEVERAL mx5 bars that have all the MSNZ paperwork but they simply don't comply to the rules. and vice versa i have seen some that are great bars but due to some silly regulation, can't be MSNZ approved.

[Mr. Shine]

Also it doesnt need to be certified from LVVT as most roll bars for mx's are behind the drivers seat and technically "not in the passenger compartment"

And this is regardless of whether it is a weld-in or bolt-in job, provided things like seatbelt anchorages are unaffected?

[SLYDIT]

yes. the rules say that if the bar is not in the passenger compartment then it does not require a cert...this is so that UTES don't have to get a cert for roll bars etc. but the mx5 slips in as behind the front seats isnt classed as an "occupied area".

theres so many people with different views on things and so many people who should know better who don't. It pays to download the relevent LVVT sections and the MSNZ sections so you can "educate" any wof inspectors and cops who think they know better.

[punkoutnz]

Yeah WOF guys tend to know their stuff, but I've had problems with cops a few times thinking they know better on various issues. Factory tints, Asymetrical tyres (of all things!), and even slotted brake rotors... So it's definitely good advice carrying the legal documents with you in your glove box.

[Mr. Shine]

theres so many people with different views on things and so many people who should know better who don't. It pays to download the relevent LVVT sections and the MSNZ sections so you can "educate" any wof inspectors and cops who think they know better.

I've often thought the same thing with carrying the documentation, and also thought the same as your reasoning on weld-in bars. Cheers for the confirmation

[zippy2]

SLYDIT, as you seem to have all the info - can you confirm my understanding, I have been under the impression that you can not get a low volume cert for any cage or bar. That these are covered on an authority card from MSNZ only ? Also that if you have a bar in the occupied area you must also have a harness rather than a seat belt, and again this needs to be covered by an authority card ?

[RMS]

There is a lot of information on www.lvvta.org.nz.

For instance this document outlines modifications that do not require certification:

http://www.lvvta.org.nz/documents/suple ... eshold.pdf

an excerpt:
-------------------------------------
Certification is not required for Roll Bars (roll protection or cosmetic) provided that:

• - each seating position is fitted with an effective head restraint; and
  - the bars are positioned:
  • - behind, following a plane extending upward, parallel to the back of the backrest on the rear-most seat; and
    - in such a way that the head-restraint would provide protection from head contact with any bar section during a crash.

For clarification, note that the roll-bars referred to here are limited to 'style bars' fitted behind the rear seats on single-row seating sports vehicles.
-------------------------------------

[RMS]

This suggests that an MX5 could be certed with a roll cage without requiring an MSNZ authority card? At least that's how it reads to me.

http://www.lvvta.org.nz/documents/stand ... Impact.pdf

2.4(8)
A roll-cage may be positioned within the B-Zone of a low volume
vehicle occupant cell, provided that
(a) the vehicle is not a modified production Class MA, with unitary
body construction, which has a permanent roof structure; and
(b) the requirements of 2.4(9) are met.

2.4(9) A low volume vehicle fitted with a roll-bar or a roll-cage, must have:
(a) a head restraint fitted to provide protection for each occupant
where a roll-bar or roll-cage section exists immediately behind a
seat, positioned between the occupant seating position and the
roll-bar or roll-cage section; and
(b) no unprotected hard or sharp bracketry including a roll-bar or
roll-cage mount, seatbelt mount, or fastener positioned where it
would be likely to be contacted by an occupant in the event of
an impact or roll-over; and
(c) all sections of a roll-bar or a roll-cage positioned adjacent to any
A-Zone must be covered in a high density energy absorbing
material which:
(i) meets SFI specification 45.1 or another equivalent
motor-sporting specification; and
(ii) is not less than 15 mm in thickness in the area facing the
occupant cell.

[RMS]

zippy:

My interpretation of the MSNZ regulations are that to compete in any MSNZ event with a roll cage or bar it must be homologated, as in it must meet MSNZ approval:

"If a safety structure if fitted to a vehicle, weather it be mandatory or optional, that structure must be homologated (certified) or approved."

That has nothing to do with being road legal though...

"Road registered vehicles fitted with roll protection, extending forward of the front seating positions, require a MotorSport/LVV Authority Card."

So as long as you meet the modification threshold requirements, you can fit a roll bar without needing a cert, but if you want to use the car in competition you will need to have it homologated.

What I'm not so sure about is the full roll cage requirements. Since you can't get a cert for a tin top MA class car it sounds like the only way to have a roll cage in 99% of cars is to get it homologated and get the motorsport authority card which exempts you from needing a cert for the cage? not sure..

Also, the clause from my previous post suggests that the MX5 could have a roll cage with an LVV cert and no motorsport authority card, but to use it in competition it would still need to be homologated.

This is all taken from this web page: http://www.motorsport.org.nz/safety-structures/

long story short, you can install any roll bar as long as it meets the requirements in the modification thresholds and you shouldn't have any issues unless you want to compete in motorsport.

[SLYDIT]

to have a CAGE you need the MSNZ authority but you don't need a cert.

basically for a road car the cert covers performance mods like turbos and adjustable suspension and the authority card/log book covers the safety items like seats/belts and cages/bars.

if you are going to pay to have someone make a bar you may as well get it homologated and get a log book. if your making it yourself and just doing road/playdays and clubsport basic events then you can avoid the homologation.

you can get your clubsport licence on line, then you apply for a log book and authority card when the rollbar is being made.(the bar has to be inspected before its painted)

[zippy2]

SLYDIT, RMS, thanks for your info, I was wanting to see what the official story looks to be.

I put a homologated bar in about 8 years ago getting a log book etc and have had no issues with WOFs relating to it.

When I put in the race seat and belts I got an authority card and that works good at WOf time as well.

I then put in the supercharger and a few other performance mods so got the cert for those. At that stage I tried to get the seat, belts and bar on the cert and was told none of these can go on the cert - they all must be on the authority card.

While this is not a major - it does mean I must retain my motor sport license and the cars log book needs at least two race entrees per year to be able to have a valid authority card

[WideOpenThrottle]

Roll-cage fabricated & fitted-in the end i had it done by Kevin Hunt of Redline Enterprises in Waimauku. Done a great job too!....plus its a bolt in one which is what i wanted.

Downside is seat travel for anyone tall as its in the way for any Formula one driver taller than about 5' 8"

[Mad Kiwi]

I have been doing some research on roll bars too, I spoke to a guy on the shore who has a business doing Roll Cages - www.rollcage.co.nz....Chubb Racing. Seemed pleasant enough and was very confident he could build a race legal (MANZ / MSNZ ???) 1/2 Roll cage suitable for tall drivers that would fit under the hard and soft top.

He said he had done it before, even laughed and said what is it with tall people and MX5's and roll cages....$950.00 ish.

Anyway, when I get some other things sorted I will be going to see what he thinks...

[punkoutnz]

I actually had someone recommend TTT Auto Engineering to me a couple of weeks ago so I'm going to give them a whirl before I go anywhere else.

http://www.tttautoengineering.com/

Apparently he does a lot of MANZ approved work. I'll let people know how I get on there, $950 is getting up there. I don't think I'll be going full MANZ though, as I wont be attending more than the occasional club day, and my bar is more important to me on the road. Ever driven next to a big lorry and though, "don't you tip on me!" Haha.

[Skilfil]

I've been wondering if its possible to have a rollbar and retain soft top/hard top capability all at the same time.

A design like the following

[Mad Kiwi]

In terms of motorsport suitability, i wonder if the single bolt mount under the seat belt is enough....?

For general road use, with the other mount points as well, I would imagine it is....

[WideOpenThrottle]

I've been wondering if its possible to have a rollbar and retain soft top/hard top capability all at the same time.

A design like the following

From memory if it fits under the hardtop it should be ok for the soft-top!

[WideOpenThrottle]

In terms of motorsport suitability, i wonder if the single bolt mount under the seat belt is enough....?

For general road use, with the other mount points as well, I would imagine it is....

Single point bolt mount is a waste of time - may as well have a style bar.....if you want safety then a four point is a minimum to prevent it from going flat if rolled on to the roof!

[SLYDIT]

from memory the msnz rules say that the main hoop plates have to be 120cm2 and have at least 3 8mm bolts and the back stays have to be 64cm2 with a minimum of 2 8mm bolts.
that bar posted from Wide open is a good solution.. only mod i would make is have the rear stay plates not welded in but sandwiched as per a normal bolt in...

i think i'll copy those pics for future reference...


oh P.S...where do you bolt your harness? will it have a harness bar?

[WideOpenThrottle]

My harness bar was left out on purpose until i get a race seat & then decide how best to put one in.

I would have prefered sandwich rear plates too but for some reason the engineer said it was too difficult because of the main chassis rail?

[RMS]

I asked this question of the LVVTA a while back and finally got an answer,

Figured it might be of interest even if it's unlikely anyone will install a full cage for the street.

http://lvvta.proboards.com/index.cgi?bo ... thread=188

[ross]

Just to show what can happen if you get caught in someone elses accident and destroy your car.
Thats why arm tethers are a good idea.
This is the style of cage for the NZ series.

http://www.youtube.com/watch?v=OfWjXzvVoL0