QLD Full roll cage?

[Orphan]

Hey guys,

I have been looking into getting a NA for a track/weekend car, I have read up a fair bit on a few forums and gathered a lot of information but can't find anything on a full cage in QLD.

Does anyone know if you are able to run a full cage in a road registered car in QLD? I have heard several answers from no you can't to yes if its engineered and meets the requirements etc. Does anyone here actually know or know of a good cage builder who knows the legislation? Given the cost of a roll bar and the fact that I want to track the car I figure if I can get a full cage legal then that is the way to go as it should give the car a fair bit more stiffness so acomplishes a lot in one go. With the overhead bars padded I can't see it being any more dangerous than a regular coupe as your going to hit barely padded steel anyways, probably a little bit better than dragging your head along the road with the roof down - still makes me wonder why 6 point harnesses aren't road legal considering how much better they hold you in your seat.

btw if anyone knows of a bargin mx-5 around brisbane feel free to let me know, I don't care about paint or mods all that much, good condition soft top and or hardtop and a straight body are all I am after as the engine will be going anyways. A 1.8L with torsen diff would be ideal but given them being fairly pricey for NA's I don't like my luck finding one.

Thanks guys.

[Steampunk]

send a PM to TCR or Cal

[rwf]

send a PM to TCR or Cal

they are both have cage in there 2f cars tcr is more of a full cage you can see it in garage

the only cheap car around i have seen was sold week and a half ago to me

build a track same as you

[Orphan]

I got in contact with TCR and he gave me some useful information. It seems it is legal in qld as long as it meets whatever adr requirements are for a roll cage which appear to be no side intrusion bars, considering they fit them in imported cars for compliance it doesn't make much sense that they aren't legal though huge cross bars would obviously not be all that good for driver access in a crash on the road but at least the driver wouldn't be mooshed through the car.

Damn you rwf Got any pics/info/price on what you got? I have been speaking to a guy over in the U.S. and i'm not so hung up on the 1.8L with torsen, waiting on pictures of his R200 LSD swap and axles, cost isn't too bad compared to buying a 1.8L torsen and you end up with a much stronger rear end for a few hundred more.

Do you guys have any good threads discussing suspension set ups etc for track and spirited driving? I was thinking of going for a set of Tein super streets with maybe the FM cromo sway bar set and all new bushings. I've dríven a few cars with the Teins and they seem quite good though I don't really have the knowledge to be able to compare them to cheaper units or the flex's, I know a poor handling car when I drive one I just don't know how to guage it vs other suspension options. There are loads of threads about brakes but has anyone done a custom set up? I have seen on a few other auto forums people getting two peice 4x100 rotors and dynalite or ap racing calipers or even skyline 4 pots and making custom brackets to fit them. As there are many standard size discs around that are a big upgrade for NA miata's I was considering going this approach, better result than using larger later model brakes and cheaper than getting a kit like the FM brake kit which by the time you get it to Aus would be hitting on $2200 for something that isn't all that hard to do yourself more economically. I'm not 100% sure what discs would work but with some research it shouldn't be too hard to find out. I also noticed on the miata.net forums everyone is having a cry about running rims bigger than 15"... is this just because most are driving with stock power and need to take every little bit of weight off they can or what? Some are even against just 16" rims let alone 17" and half the forum brakes out into calling them clown shoes and saying they will perform terribly because what you want is a huge side wall and tiny rims with rubbish brakes under them. Once you start going for above stock power levels I can't see there being any negative issues even more so if they are required to clear larger brakes. The biggest issue seems to be a lack of the 235/245's to fit 17" rims and in cases 16" rims with a close to stock rolling diamiter.

[rwf]

you car see my na on garage

and i would say head out to the next round of pscraq and chat to the guys that race and you will see what a mx5 na needs to go fast and stop

[D-Train]

Hey Orphan, just wanna bring up a point i think you are missing in regards to rim/tire sizes. I'm not against larger rims at all, however, i would tend to agree with what everyone is sayin with going up to a 16 or 17" wheel, especially when tracking a car and getting the most out of it. I have 2 other guys i do sprints with, one running 17's the other 16's and i run 15's. Now i find with my 15's that even though it is 1' bigger than the stock wheels they are a perfect fit, no fouling on the guards even if i drop my suspension all the way and i can find a plethora of tires to fit it with no problems at all. The guy with the 16's decided it was the right choice until he decided to put some real sticky rubber on it and found it to be a problem 1. It ended up rubbing on his front guards with stock suspension and 2. The smallest tire he could find for a 16 was a 205/50 which for that car is a chunky tire. And old mate with the 17's had rubbing issues on stock suspension and he could not find a semi or a slick with a very low profile to accomodate, at best he was running on high performance road tires. The point i'm trying to put across is that the tires the are made for track type work are constructed in a fashion so as to maximize the stiffness of the sidewall and correct me if i'm wrong but i am not aware of a tire with a sidewall in a profile less than 45 for a slick or semi simply for the fact that it is more difficult to construct in a sidewalll that is no more than and inch thick, and if there was i don't think i would use it for fear that it would flex the tire that much under heavy cornering that it would come straight off the rim. I would be keen to here others' opinions on this point also though. I just think that if you want big rims leave them at home on track days, other days no probs!

[Orphan]

rwf I couldn't find your car in the garage, can you post a link for me? Thanks.

D-Train I guess the part I am finding hard to understand is how clearance is any different with a larger rim that ocupies the same space with a tire of the same rolling diamiter. If they take up the same space I can't see how a larger rim has less clearance etc. The tire choices definately seem to be the main obsticle, I have had a look around and it amazes me how few options there are for even 16" rims that would suite the miata, loads for 15"ers just nothing for 16 or even 17" without increasing the rolling diamiter. In regards to no slicks with a profile less than 45 I think thats more dependant on width but I have to agree I can't say I have seen anything less than 40-45ish. Plenty of supercars run 35 profile tires so maybe there are slicks out there to suite but if so they would be for 19-20" rims though most I have seen drop down to an 18" rim for slick use. Interesting tid bit is the F430 comes with 225/35/R19 front tires and 285/35/R19 rears, I guess that just helps to show its about the compound not about how wide it is, I would still like something a bit wider than a 225 on the rear though.

Part of the reason for this car is so I can learn about all of this practically rather than just read about it. Can't wait to hit up the track, are there many instructors/driving courses available at QR? By road standards I would say I am alright, everyone can always improve but by actual driving and handling a vehicle standards i'm still at level one compared to anyone who can actually drive and I would really like to change that but my 1550kg+ open diff luxo barge isn't really the best car for that type of driving.

[rwf]

225 is to much

If the guys that race mx5's na are running a 15x7 with 205 /50/15 r888 Toyo tires

That would tell me this is the best why to go

This is a small light sports car not a v8 supercar

The last na I sore on the track with 17 on it did not drive it home as he hit a wall and said good bye to his mx5
they get too hot and don't grip

[hks_kansei]

- still makes me wonder why 6 point harnesses aren't road legal considering how much better they hold you in your seat.

can't comment on the rest but this one is for visibility.

If you've ever dríven on the road wearing a harness and tried to change lanes you'll know why they aren't road legal.

[D-Train]

If you've ever dríven on the road wearing a harness and tried to change lanes you'll know why they aren't road legal.

Haha! When you got the top down its ok, but thats what i found with mine, reversing is even harder.

[Orphan]

My torso does not move when I shoulder check so I'm not 100% sure how much it could impact shoulder checks for lane changing etc, definately a bit annoying for reversing if you need to twist around to have a look. Ad a helmet into the mix on the track and I can understand it being a bit difficult but thats not an issue on the road.

I spoke to Keith Turner (one of the FM guys) and he said they have 350rwhp+ V8 swaps running sticky 225 rears so I guess with my power goal of 250-320rwhp the 225's should be fine as long as they are a good compound. Probably end up with 205's on the front and 225's on the rear or something like that. As for rims I definately agree 15's are the best to go with but more for tire choice as there are simply almost no tires for 16-17" rims to suite the MX-5's rolling diameter, you need to get into the 9"+ wide rims to find any profiles that might be close to stock though the only cars running rims like that are full on wide body track cars so rolling diamiter isn't of much issue to them as they can run whatever they want and make it fit.

Does anyone here have the toyo R888's? How long do they last when tracking them? Semi slicks wear out far to quick on the road so I would definately be going two sets of rims one with something a bit sticky and the other with road tyres, maybe something like Federal SS595's or 595 evo's for a bit better compound. Does the $300 range sound right for the R888's? Definately a step up in price over road tyres which is another reason I will have two sets. Has anyone used Federal 595RS-R's? I have heard good things about them from a few people but I don't have any experience with them personally - can get a nice discount on them is the reason for mentioning federals.

[Jeo]

I thought the reason they needed to be engineered was that they posed a significant danger in an accident if they were poorly built.

[Orphan]

I thought the reason they needed to be engineered was that they posed a significant danger in an accident if they were poorly built.

I would say that is part of it as there are requirements for minimum thickness and grade of steel, if its cro mo the welds have to be checked unpainted but doesn't appear to be the case with mild steel. If its built properly it should stay structurally good in the case of a crash, have a look at all the nurburgring crashs, even more so that M3 crash recently, hardly any of the car is in tact but the cage looks 100% and nothing intruded into the cabin, half the time the cage and floor are about the only things left in place and I trust a steel frame around me more than a flimsy open top windshield. The biggest issue I see is the overhead bars being so damn close to your head with stock seat height. Could probably get a few inches more clearance by loosing the sliders and bolting the seats to the floor with some rubber spacers to help reduce vibration. Remember the idea for the cage is that they don't cost that much more than most good roll bars in aus for what you get, they stiffen the car up a hell of a lot from everything I have read and seem to be much safter in a crash as long as you dont crack your head open on them.

[tbro]

Have a read of the CAMS manual Racing and you'll find out the info that you'll need if your looking at building a MX5 racer, or go out to Lakeside on the 3rd of May and you'll probably find some who have been there, done that. There's no reason to reinvent the wheel when your first starting out.

Terry

[Orphan]

Haha the whole point of asking on the forum was to see what has been done and what is legal, not trying to reinvent the wheel. I have done a lot of reading over the last week regarding suspension/wheels/tires/etc etc and have a much better idea now.

Has anyone here got Tein SS's or Tein Flex's in their MX-5? Interested in the difference between them, considering the SS's in aus are re valved for harsher roads and the flex are suppose to be stiffer by all counts even on lower damper settings I'm guessing they don't make for the best road suspension. Can anyone comment?