cutting the parcel tray

Bwarp · Post by **Bwarp** » Wed Oct 17, 2012 9:25 am

Anyone know the legalities etc of cutting the parcel tray to fit a rollbar that bolts into rear strut tower area?

Looking at getting one made by frostmotorsport, if it ends up going ahead, the he could be able to make a few more, if any other punters are keen too. I'm chatting with him tonight to get the ball rolling.

evel · Post by **evel** » Wed Oct 17, 2012 9:36 am

dont really know any of the goods about cutting up the parcel tray but Id be keen on a roll bar just depending on price and what it looks like.

Angreal · Post by **Angreal** » Wed Oct 17, 2012 10:02 am

Bwarp wrote:Anyone know the legalities etc of cutting the parcel tray to fit a rollbar that bolts into rear strut tower area?

Looking at getting one made by frostmotorsport, if it ends up going ahead, the he could be able to make a few more, if any other punters are keen too. I'm chatting with him tonight to get the ball rolling.

My tray is cut. Don't see any problems with it since the tray isn't exactly structural and with the carpet put back down no one would ever know.

Bwarp · Post by **Bwarp** » Wed Oct 17, 2012 10:06 am

Im expecting close to 1k for roll bar. Want it to be good. And im not too fussed on what it looks like, I want it to save my neck if I flip the car. If I was going for looks I'd go without a bar, cos a style bar will do you more harm than good haha.

Snapfrozen · Post by **Snapfrozen** » Wed Oct 17, 2012 10:10 am

Bwarp wrote:Im expecting close to 1k for roll bar. Want it to be good. And im not too fussed on what it looks like, I want it to save my neck if I flip the car. If I was going for looks I'd go without a bar, cos a style bar will do you more harm than good haha.

Let me know what the price ends up being. Definately keen

Timmo · Post by **Timmo** » Wed Oct 17, 2012 11:01 am

Im going to go and see a local outfit today for the same reason.

The options I've considered are:
1) Another 'don bar' like I had in my NA....don't really like the style of it but it is bolt in and well priced
2) Importing a Deuce from the US- I like the look of these and they are tough for a double hoop. The shipping was more than the bar itself

On further inspection, because the lower brace sits under the parcel tray, the hoops are a fair way back meaning that hoop height is limited by the roof height sloping back- They only sit about seat top height which, with a helmet, isn't quite enough I feel.
3) Getting a copy made locally (i.e. bolt in)....Decided this may end up being expensive for a one off for all the measuring time etc. It does have the advantage of a possible market for subsequent bars though.

So am now looking at a Deuce type roll bar (i.e. double hoops) but welded in so that measurements can be a little less accurate and will mean (hopefully) things are cheaper with less bolts and fabrication time. I would like to modify it to bring the hoops closer to the seat, bringing the feet and lower cross brace down in front of the rear bulkhead so I can go a bit higher with the hoops.

What do you envisage your roll bar will look like bwarp? (yeah yeah I know, looks aint everything but I figure if it's possible to have both a good looking and functional rollbar, then why not?)

SLYDIT · Post by **SLYDIT** » Wed Oct 17, 2012 11:41 am

A four point bar with diagonal and harness bar AND MSNZ logbook should be about $700. A grand is a bit expensive IMO. it would have to be perfect for that sort of money. theres a guy on trademe adverstising.

Timmo · Post by **Timmo** » Wed Oct 17, 2012 11:43 am

So what's the deal with the MANZ log book and cert (in terms of extra costs)

My understanding is that a) as long as the bar isn't forward of your head, you don't need it certed which for what I want the bar for (trackdays) is a plus.

Bwarp · Post by **Bwarp** » Wed Oct 17, 2012 11:52 am

Yeah ilve just budgetted for 1k cos it'd still work out cheaper than to get a harddog from the states. Budgetted for 1k in the hope I'll be pleasantly surprised.

I was gonna do half cage with harness and log book but I cant get the seat low enough to fit my head under the 50mm clearance required to get it homologated whilst still fitting it under my hardtop.

Also re: style - it'll be a main hoop with back stays going through parcel tray and potentially a diagonal bar or two between the rear stays.

Would prefer something bolt in, but will potentially go for weld in if it makes it easier for my fabricator.

For those of you that know of Fraser Simpsons NSX (featured in Pcar mag) he did the full extensive roll cage in that, so what im looking at getting will be near perfect if he's got anything to do it!

Mr. Shine · Post by **Mr. Shine** » Wed Oct 17, 2012 11:59 am

Suppose the parcel tray comes under vehicle structure, and the LVVTA certification thresholds don't mention non-structural cuts specifically, so I guess strictly speaking it would need certification...

Timmo · Post by **Timmo** » Wed Oct 17, 2012 12:01 pm

Not speaking from any position of authority/knowledge, I can't see how it would be deemed structural- It is simply a thin piece of metal to flatten out that area...its only held on with small (8-10mm) bolts?

Bwarp · Post by **Bwarp** » Wed Oct 17, 2012 12:52 pm

Mr. Shine wrote:Suppose the parcel tray comes under vehicle structure, and the LVVTA certification thresholds don't mention non-structural cuts specifically, so I guess strictly speaking it would need certification...

Its going for cert anyway, so thats fine. I just wondered if there was a right or wrong way to cut it.

Mr. Shine · Post by **Mr. Shine** » Wed Oct 17, 2012 12:52 pm

Timmo wrote:Not speaking from any position of authority/knowledge, I can't see how it would be deemed structural- It is simply a thin piece of metal to flatten out that area...its only held on with small (8-10mm) bolts?

Certification thresholds don't make any distinction between structural or non-structural alterations; anything that's not specified in the thresholds guide requires certification.

Bwarp wrote:Its going for cert anyway, so thats fine. I just wondered if there was a right or wrong way to cut it.

Yeah, I wasn't sure if you'd already done cert or would need re-cert. The parcel tray is at least half made up of the removable steel panel, but I'm not sure how much that'd be considered to be part of the vehicle structure

Consult certifier?

Growler · Post by **Growler** » Wed Oct 17, 2012 1:07 pm

You could always stich the parcel tray to the actual roll cage once done.
That would help increase the rigidity of the shell a little more...
In racing you require a barrier between the petrol tank and the driver. I believe this needs to be airtight in case of fumes getting into the cabin.

Timmo · Post by **Timmo** » Wed Oct 17, 2012 1:08 pm

Well just went and talked to SpeedFactor here in Tauranga (seem like a top-quality outfit)- They had made one a while ago but for an NA (so the rear stays would need to be brought forward to allow the glass rear window to fold) and it was a simple single hoop with diagonal brace.

As an estimate to fabricate the design I wanted, it was ~$1200 plus would need to be certed (either a LVVT or MANZ).....so looking near $2000....which is almost getting into 'screw it, I'll just buy a Honda S2000' territory when you start to factor performance potential and costs.

Growler · Post by **Growler** » Wed Oct 17, 2012 1:22 pm

Have you tried Andy at Race FX?
He is now situated at the last garage on the left as you drive into Hampton Downs.
I have known him a long time and he has been in the business for many years. (I did work for him for a few weeks while I was in-between work. Ended up doing a lot of work on the Ferrari F40 replica he built).
He did the cage for the MX5 that came over for the land speed record quite a few years ago, and has done a few members cars as well.

chris · Post by **chris** » Wed Oct 17, 2012 1:35 pm

Just jumping in, My roll bar has the parcel tray cut out and fitted back in was a total pain in the ass but came out nicely

Bwarp · Post by **Bwarp** » Wed Oct 17, 2012 2:22 pm

Timmo wrote:
As an estimate to fabricate the design I wanted, it was ~$1200 plus would need to be certed (either a LVVT or MANZ).....so looking near $2000....which is almost getting into 'screw it, I'll just buy a Honda S2000' territory when you start to factor performance potential and costs.

3k mx5 plus 2k roll bar wont get you an S2000.....

Also. Cert is like 4-500 bux. Can't put a price tag on being able to walk for the rest of your life.

Motorsport authoirty card is also cheap as chips btw, but they'ed never give you authority card for a double hoop style bar type thing.

Mr. Shine · Post by **Mr. Shine** » Wed Oct 17, 2012 2:22 pm

Timmo wrote:As an estimate to fabricate the design I wanted, it was ~$1200 plus would need to be certed (either a LVVT or MANZ).....

What was the basis for it requiring certification?

Snapfrozen · Post by **Snapfrozen** » Wed Oct 17, 2012 2:38 pm

You also won't need an authority card as long as it sits BEHIND the most rearward seat in the vehicle

Timmo · Post by **Timmo** » Wed Oct 17, 2012 3:26 pm

Mr. Shine wrote:
Timmo wrote:As an estimate to fabricate the design I wanted, it was ~$1200 plus would need to be certed (either a LVVT or MANZ).....
What was the basis for it requiring certification?

He wasn't sure if it would be needed or not- I suggested it wouldn't need to be (due to the reason snapfrozen pointed out).

Does anyone know what is case definitively? If a roll bar is behind the rear seats does it need any type of cert?

Timmo · Post by **Timmo** » Wed Oct 17, 2012 3:34 pm

Bwarp wrote: 3k mx5 plus 2k roll bar wont get you an S2000.....

True, but a 8-9k MX5 + 2k rollbar + whatever else is needed to get ~ 230hp (i.e. the same performance potential as an S2000) is getting mighty close.

To make it clear, my car isn't a track car. It's a road car that I like to do track days in so our aims etc are a little different.

Also, if you can't put a price on being able to walk for the rest of our lives, why are any of us driving at all? Let alone a small convertible (roll bar or not)

Angreal · Post by **Angreal** » Wed Oct 17, 2012 3:37 pm

Timmo wrote:
Bwarp wrote: 3k mx5 plus 2k roll bar wont get you an S2000.....

True, but a 8-9k MX5 + 2k rollbar + whatever else is needed to get ~ 230hp (i.e. the same performance potential as an S2000) is getting mighty close.

To make it clear, my car isn't a track car. It's a road car that I like to do track days in so our aims etc are a little different.

Forgot to account for prices for Honda servicing and parts

That should bring it back in favour of the MX

Mr. Shine · Post by **Mr. Shine** » Wed Oct 17, 2012 4:19 pm

Timmo wrote:Does anyone know what is case definitively? If a roll bar is behind the rear seats does it need any type of cert?

http://vehicleinspection.nzta.govt.nz/v ... ior-impact

Snapfrozen · Post by **Snapfrozen** » Wed Oct 17, 2012 4:40 pm

Mr. Shine wrote:
Timmo wrote:Does anyone know what is case definitively? If a roll bar is behind the rear seats does it need any type of cert?
http://vehicleinspection.nzta.govt.nz/v ... ior-impact

Im about to rush out, but iirc. As long as it falls behind the rear seats it is a roll bar or half cage, and can be certified by an LVV certer, or can be used for motorsport (obviously has to meet regs) and have an authority card and logbook. The second it extends beyond the rear of the seat it becomes a "full cage" and requires motorspot endorsement

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