New Race Class

Keith Jones · Post by **Keith Jones** » Sun Jun 12, 2011 9:19 am

A new race class has just been launched in Auckland.
This looks as if it would suit road going MX5s which have good suspension and brakes setups, but no power mods.

Euen · Post by **Euen** » Sun Jun 12, 2011 6:36 pm

I assume that the "no cage required" condition will not apply to MX5s. I would not want to race a 5 without one.

Angreal · Post by **Angreal** » Wed Jul 06, 2011 9:31 pm

I'd love to take it up... I just have a phobia of nailing the car somewhat.

So by "no power mods", does a bigger intake and extractors count?

Angreal · Post by **Angreal** » Wed Jul 06, 2011 9:44 pm

Another question, how much does it costs to install a harness and a roll cage? Would these need to be certified?

Brainflex · Post by **Brainflex** » Thu Jul 07, 2011 6:04 pm

In a convertible a half cage definately doesnt need certing, a full cage can be done without certing if built to stay out of certain areas. A harness would if it was permanently fitted, keep it removable using eyebolts n carabiners with a standard seatbelt as well. Cant fail what isnt there.

sprsta · Post by **sprsta** » Thu Jul 07, 2011 6:53 pm

can not have roll cage without cert and log book

a roll bar is fine as it is behind the rearmost occupant

Keith Jones · Post by **Keith Jones** » Fri Jul 08, 2011 8:40 am

MANZ rules for racing are a bit Catch 22. You don't have to have a roll bar or cage to race, but if you have got one, it must be built to MANZ specifications and homologated. The cost for a MANZ spec roll bar, with main hoop, rear supports and a diagonal (the minimum allowed) will be +/-$1000. A four or five point harness will be around $300-400.

My comment about "no power mods" was related to the minumum lap time, not what could or couldn't be done to the car. A standard NA or NB would probably lap Puke in more than 80 sec. As long as what you have done to car doesn't take you under the that, it's fine. The trick is to do just enough to stay on the right (wrong?) side of 80 sec without sandbagging.

Growler · Post by **Growler** » Mon Jul 11, 2011 12:20 pm

Well that counts me out. I managed a 1.20something once chasing a Datsun 1200 race car! And that was with a standard MX5 (1600) with modified suspension.

SLYDIT · Post by **SLYDIT** » Tue Jul 12, 2011 9:28 am

oh by the way you CANNOT use a harness with the standard mx5 seat.

so to go racing in this class you'd need:

A half cage roll bar (wouldnt race a mx5 with out one on the track)
a racing seat
a 5 point harness
a decent fire extinguisher.

for events like autocrosses,sprints and "clubsport" events you do not have to have a MANZ approved roll bar. anything more and the roll bar must be approved.

if this event is classified as a clubsport or lower event then a bar similar to the "brown davis" bar would be a good start.

http://imageshack.us/photo/my-images/4/p1000499v.jpg/

punkoutnz · Post by **punkoutnz** » Tue Jul 12, 2011 11:46 am

That's exactly the type of bar I'll be looking at when I get one! Are they available in New Zealand? So far the only bars I've been able to find by trawling the net are the horrible shiny things from mx5mart.

SLYDIT · Post by **SLYDIT** » Tue Jul 12, 2011 1:44 pm

theres no reason why you couldnt import one from aus. have a look at the mx5 mania site. alternatively you culd do a google search for brown davis roll bar install images and take these pics to your local roll bar builder to base one from.

this might give you a few ideas too.
http://www.clubroadster.net/vb_forum/sh ... 29&page=10

unfortunaty the MNZ regs are stupidly restrictive on what is legal in NZ. for instance those brown davis bars are CAMS approved in australia but would never be MANZ approved here in NZ due to MANZ INflexible rules.

Brainflex · Post by **Brainflex** » Tue Jul 12, 2011 5:26 pm

I was quoted $795 for a four point half cage welded into my MX5. That included MNZ cert.

punkoutnz · Post by **punkoutnz** » Tue Jul 12, 2011 6:31 pm

I thought about importing one but the freight costs were a bit of an unknown so potentially a large factor indeed! If I'm going to go to the trouble of getting one on the car I might as well take the steps to get one that's manz approved. When the time comes I guess I'll jump back into the research barrel and see what I can come up with at the time, though one that's similar to the browns davis bar looks just the ticket.

SLYDIT · Post by **SLYDIT** » Tue Jul 12, 2011 9:00 pm

basically in NZ you can't get a bolt in cage approved by MANZ due to a few unique "features" of the mx5.....

1) they wont allow bends in the main hoop fore/aft meaning you can't use the floor as a mounting point.(putting a straight bar in interferes with the seats and belts)
2) they will only allow a 100mm square base plate for the main hoop with 4 bolts for mounting.(try finding anywhere useful on the mx for those that isnt the floor)
3) they won't allow the back stays behind the shock towers but the only accessible bolt point for the back stays is.............. behind the shock towers.
4)also the diagonal brace is a bit doubtful on most bolt in bars as they require it to go from the very corners of the bar to the mounting plate which is difficult to acheive with a bolt in...

so theres the fun and games that the pen pushers put us through when overseas bars that are "banned" in NZ are used everyday in SCCA racing in the states and CAMS racing in Aus.

punkoutnz · Post by **punkoutnz** » Tue Jul 12, 2011 11:08 pm

So what you're saying is, "bugger it, buy a decent bar that works and bolt it in". Chances are I wouldn't be entering any hillclimbs and the such anyway, perhaps the occasional motorkarna and maybe a track day or two (which there's no way in hell I'd do without a roll bar!)

Angreal · Post by **Angreal** » Wed Jul 13, 2011 10:04 am

So to get a cage that complies would require a ton of money and make it difficult to get in and out of the car?

Euen · Post by **Euen** » Wed Jul 13, 2011 11:25 am

A half cage (rear section) could possibly be done without spending vast amounts. A half cage shouldn't inhibit access too much either as it will be behind the seats. The issue is around mounting it in and stlill keeping some clearance around the rear of the seats. The other thing to consider with a MSNZ approved cage is that of clearance from your helmeted head. If you are tall, you may find that you cannot get sufficient clearance to the main hoop. There are only really 2 ways around that. One way is to lower the seat (eg racing bucket mounted directly to the floor) or run with the top down all the time coz the main hoop will be too high to raise the top.

Full cage is another story altogether as a good one will include side impact protection which will impede access. A full cage also requires certing and a MSNZ Authority card. A full cage is not really something to contemplate unless you are getting into serious motorsport.

http://www.motorsport.org.nz/safety-structures/
http://www.lvvta.org.nz

zippy2 · Post by **zippy2** » Wed Jul 13, 2011 2:22 pm

I had a half cage built, powder coated and installed (bolted), paper work done, MSNZ log book and cage approved included all as a drive in drive out service for $750 a few years ago - (in Wellington).

see page 3 on my cardomain site (link in my profile)

SLYDIT · Post by **SLYDIT** » Wed Jul 13, 2011 6:55 pm

thanks for the post mike. nice bar.
just a few questions...

how many bolts do you have holding down the rear stay and main bar plates?

How are the main hoop bolts secured (isn't there a box section under that main hoop plate?)

any more pics particularly the mounting points?

Keith Jones · Post by **Keith Jones** » Thu Jul 14, 2011 5:09 pm

I found a guy in Hamilton who will make MANZ approved bolt-in roll bars for MX5s. He hasn't done one to the new specs with the larger main hoop diameter yet, so the final price is subject to confirmation, but he reckons they should be around $500. This is for a design to the minimum MANZ spec - main rear hoop, 2 backstays and 1 diagonal.

If you are interested PM me and I'll give you his phone number.

BTW, I was given incorrect info by one of the race organisers. Under current MANZ rules MX5s do need a minimum of a roll bar. See http://www.motorsport.org.nz/safety-structures/

Brainflex · Post by **Brainflex** » Thu Jul 14, 2011 5:17 pm

Do you know if they will fit under a top?

Euen · Post by **Euen** » Thu Jul 14, 2011 6:03 pm

See my post above. The height of the main hoop must meet minimum clearances from your helmeted head. A hoop can be made to fit inside the top but if it is below the top of your head you are wasting your time and money. Only option is to lower the seat. To take it to the extreme, I have seen one build where the guy cut out the floor and dropped it by a couple of inches to get his seat low enough.

Keith Jones · Post by **Keith Jones** » Fri Jul 15, 2011 8:30 am

Head clearance from the hoop can be an issue in an MX5 if you are tall, as Euan has mentioned. My roll bar fits under the soft top OK ( the builder made it to do so) and clearance isn't a problem even with my race seat on the original MX5 seat runners. I'm 1.73m.

Euen · Post by **Euen** » Fri Jul 15, 2011 9:33 am

Yeah, its alright for you little buggers

but I am 1.88m

zippy2 · Post by **zippy2** » Fri Jul 15, 2011 10:04 am

SLYDIT wrote:thanks for the post mike. nice bar.
just a few questions...

how many bolts do you have holding down the rear stay and main bar plates?

How are the main hoop bolts secured (isn't there a box section under that main hoop plate?)

any more pics particularly the mounting points?

will see if I can get some more pics and count the bolts later today for you.

The bar was built and installed to fit under a soft top, allow the race seat (on MX5 sliders) to go all the way back and allow my helmet to meet the 50 mm rule (at least I think that was the rule) If you are tall you will need to find a lower seating than the standard seat height.

the bar has plates welded underneath that the bar then bolts through - so it is possible to remove.

Additionally, as far as I am aware you do not need an authority card if you only have the bar - however if you put in a race seat and 4, 5 or 6 point harness you will need the card to be able to get a WOF.

New Race Class

New Race Class

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