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Brake and wheel options to keep VASS engineers happy...


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#1 Dan260Z

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Posted 19 June 2012 - 12:51 PM

OK so whilst I slowly progress through the metal work on the body of my 260, I've started looking at brakes and wheels as a nice distraction from all the hammering and welding.

I don't have a file set up with a VASS engineer yet, as I prefer to suss them out before handing over cash, but I have been talking to one in Eltham (VIC) about brakes and wheels.  He's obviously been reluctant to give too much away before I start throwing him cash, but I have managed to get some important pointers on brakes and wheels, which i thought might be of interest.  Conversely, if anyone is able to share their experience with engineers, or offer advice on ways to satisfy these restrictions, let me know!

Front Brakes:
Wilwood-caliper based kits:   He's not happy due to no dust seals.  Reckons it means I'll have to rebuild each time I change pads to avoid jamming dust into the seals when I push the pistons back in.  Also I found this, which pretty much confirms it http://www.infrastru..._01Jan2011.pdf 

Hilux 4-pot/vented discs:  Much happier with this idea, but he's still concerned about re-drilling discs to 103mm PCD to bolt to the back of the hub, if the discs were originally designed to sandwich between a hub and wheel.  Wanted full drawings of how i intended to modify the discs, etc.  I assume I'd be right if the disc I use originally mounted to the rear of a hub, or has a really thick centre hat/flange (the stock 260z front discs is 9mm thick at that point).

Alternatively he suggested using 2-piece discs.  $$$$ I assume :(


Wheels: 
I quized him on the Vic roads rule of "1" wider than the largest factory fitment", hoping he'd say "nah she's all good if you're getting it engineered".  No such luck.  The rule stands, restricting us to 6.5" rims (based on my stock 4-spoke mag being 5.5"), unless I can prove that the wheel bearings were used on some other model/type of car which was fitted with wider rims from the factory!  So far no luck finding that sort of info.  My only glimmer of hope is that the ZG came with wider wheels (since it had factory fitted flares).  But I have no idea what sort of wheels the ZG's ran.

Any thoughts, on any of these points would be very welcome!  Esp from those who've sucessfully got a brake or wheel upgrade through engineering!

#2 dat2kman

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Posted 19 June 2012 - 01:12 PM

One day, maybe, someone who has the equipment and ability ( not me !) and who has a full set of Federation DeLa Automobile Internationale - FIA,  homologation papers ( me !) and can do a high resolution scan.

These were a set of papers that showed the Z cars were able to be supplied with a large array of "standard" sports option parts, brand new made by Nissan, to be sold by any dealer, to any customer, that wanted to enhance their new Datsun Z model.

It details four piston brakes, vented rotors, flares, front airdams, rear bobtails, wheels up to 10" wide.
Upon disclosure of this official Nissan factory documentation, you should be able to find a "friendly" engineer.

The parts were not just for circuit racing, but were fitted to many cars over many years and registered for use on public roads in countries all over the world.
In the USA a particular ZX model 1970's, early 80's, was fitted with 15" diameter rims, isnt the rule 2x2 ie 2" bigger diam, and 2" wider???
East Africa was very popular with these registered enhanced Z cars, a lot of dirt roads there though!

#3 Dan260Z

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Posted 19 June 2012 - 01:45 PM

Wow - Sounds like exactly what I'm gonna need to make my life a whole lot easier!

The obvious qn now is - how do i go about getting my hands on a copy?  or, at least, on a copy of the relevant sections (eg. brakes and wheels)?

I'd be happy to spend the time scanning - but it looks like it'd be one hell of a drive for me to come up and borrow the papers from you to do it! :-P 

Can you offer any advice as to where I might be able to obtain my own set?  Happy to pay for them.

#4 1600dave

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Posted 19 June 2012 - 04:32 PM

With the redrilled rotors, have a look at how Datsport do it (datsport.com) . I believe they sandwich the redrilled rotor between the back of the hub and a steel "ring" - ie it goes Hub --> rotor --> steel ring --> bolt head. Not 100% sure, I was lucky enough to find some blank rotors that had been drilled to the correct size.

All their stuff is (I am pretty sure) certified for the street. I was looking at making a dogbone to adapt R32 calipers to earlier struts, my engineer wasn't happy with me making them, but was OK with buying the Datsport dogbone as it was fully tested and certified.

Sorry for being a little vague, just thought it may be a starting point.

#5 dat2kman

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Posted 19 June 2012 - 06:13 PM

Dave W, check on that hub rotor ring thing, only concern will be expansion/contraction multiple times.
It can be bad enough with just hub to rotor.
Other option, sometimes rotor manufacturers can supply undrilled and smaller/unfinished centrebore hole.

If one xisting hub mount hole is used, in say a five hole rotor, and three new holes drilled, with stress relieving chamfers, it should ne an issue, but, i reckon most engeers will want to er on side of caution, as well as "known and certified" suppliers.

#6 nat0_240_chevZ

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Posted 19 June 2012 - 09:27 PM

yep, basically not want to engineer anything, ie do the calcs and engineering checks required, its just their way of saying yay or nay,taking your cash
whilst someone else has liability of the mods, ie 'x'sport or any other aftermarket manufacturers, whom just usually modify stock gear anyway.

yes, some rotor manuf. do sell blank rotors. some do custom hole patterns on a std rotor too but pricey and lead time is a killer.

Id suggest you put the hilux/landcruiser calipers on and let them try to tell you that they are not standard fitment for this car, provided you dont butcher the std splash shields when cutting new shapes for the 4 pots. make them nice and neat and re-paint etc

Alot of the 'engineering' work performed by theses guys is a load of BS, there is way too much red tape and insured liability involved, for them to begin to even think about crunching numbers and getting involved, its not worth it to them, but your money is....
'known and certified',  (if any thing even does exist),
means:  yep, they have made money from these things
and yep making claims which they can be hounded for said money if so required......

think about this, how many cars, even current ones have fatal design flaws which have sailed right past ADR compliances? and how many of these said parts have been used in modified conversions, upgrades etc etc.
may i speak ford territory, holden commodore, hyundai excels, daewoo where do i stop.

As for wheel bearings fitted on another car? maybe check out xf falcons? or other larger fords? im pretty sure they are not that different to the datto's
also look at z31 300zx, r31 skylines etc etc, how about using that hub off another car? ie said falcons and other nissans??
and even making that comment about other cars which use those bearings.
this comment does not conform do engineering design principles, pholisophies or even common sense, as the size of the bearings, although the same as another could fail dramatically due to other such factors, like the distace between the bearings, remarkably more detrimental for the bearings if closer together than spaced furthar apart, which would cause a bearing to fail, due to greater moments during dynamic loading, diameter of the wheels, weight of the car, grip of tyres, if you hit a gutter whilst turning, clip a granny crossing the road.
for gods sake mr engineer pick up the bearing catalogue on your book shelf and have a damn look, read the numbers....
this guy needs to be reported, as these generalisations cause more troubles than they think they are preventing.
OK on the flip side, yes I agree cut springs, welded suspension & braking components big NO NO,
or wheel spacers 6" thick & wheel studs 2 feet long, wheels protruding from flared guards is stupid, please slap these kids in the head...
rant complete.

dont take your car to that idiot, please pm me his business/contact details, I would like to write him a helpful letter
me

#7 Dan260Z

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Posted 20 June 2012 - 12:56 PM

Cheers for the heads up on datsport 1600dave, I'll check em out.  I recently bought a set of volvo 240 4-pot calipers with some 290mm red-drilled 5-stud rotors (mystery source) off ebay which was advertised as bolt on (they weren't, 76mm caliper mountsing vs 90mm on the zed, hello..) - anyway they had rings on both sides of the disc similar to what you describe.

Prob with drilling a 5-stud rotor is that you'll never find one with a 103 PCD.  So even if you use one of the exisiting holes, you'll have to elongate it down towards the centre.

So far it's looking like non-turbo Z31 300zx 2+2 discs are the go (4 mounting holes, originally designed to be mounted behind the hub like the 260z, only you need a spacer to centre it betsween the pads of most 4-pot calipers, like this http://www.pape.ws/a...ake Upgrade.htm )  combined with the '89-95 Toyota 4x4 Pickup caliper.  Will confirm once I actually run this idea past an engineer.


I see what you're saying nat0... they're not really "engineering" anything - they're simply relying on someone else's engineering work (usually car OEM's).  It's easier for them to say stick with unmodified factory components that give them the warm and fuzzy feeling, than to crunch some numbers and expose themselves to risk by being the first to try something new.  That said, as an engineer myself (electronics) - I know that part of the process includes a lot of testing before a part can be qualified.  So I guess a VASS engineer could either get you to build multiple copies of a given set up and make you run all sorts of tests on them - or he could just say "use stuff that's already been through that process"

But yeah, I agree - the world is just full of people trying to hand-ball liability these days.  I spose I am too by getting the mods engineered if you think about it!

My plan is to put together a plan for the car, then interview a few engineers over the coming weeks before choosing one.  If anyone in Vic can recommend one, let me know!  I'll keep you posted.


Dat2kman - I'm still extremely interested in finding out more about those 10" wheel options, as it's no-doubt going to be a big point of contention with the engineers, and I've already started making up some custome flares in the hope of running some XXR 522's in 16x8.25" with +0mm offset (My car came with damage on the LH guard, so i figure the easierst fix is to cut it out and fit flares - only flares look silly sitting 2" in!)
I'd be happy to donate to the site if you'd be able to scan or photocopy some of the relevant pages concerning just the wheel options...

#8 Agno

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Posted 20 June 2012 - 02:42 PM

The biggest issue VASS engineers have is the enormous liability they shoulder. Once they sign off a car as safe, if anything was to happen to that car they are personally liable for any failure, even after they have retired or on their death bed!

Without fully knowing the way they operate I'm assuming VASS engineers like to use proven parts or parts that have a guarantee  because they would be able to push some liability the fabricator's way should anything happen to the car. Call it lazy or slack but it's probably better business sense than telling someone who is just trying to pick their brain without paying exactly what they would need to engineer their car. I'm sure if you were to stump up the cash with them they would do the necessary calcs to certify your mods safe.

#9 dat240z

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Posted 22 June 2012 - 02:43 PM

Im in the process of engineering including wilwood discs all round and although they are not ADR the can be engineered here in the ACT...

#10 Six_Shooter

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Posted 24 June 2012 - 05:13 AM

Off topic:

I'm glad I don't live where you guys do, I'd never be able to modify my cars. Pretty much everything I do is a "home grown" modification, many include one off parts made by me (or my grandfather), that would either never get "approved" or have to go through a lot of red tape down there. I'd be VERY limited by what I could do, which would not make me happy, or I'd have to have a LOT of money just to do things the way I wanted.

Don't get me wrong, I like the idea of needing a modified car approved, or inspected, to make sure blatantly bad ideas are not allowed on the street, I've sen some doozys in my time working on and being around vehicles, but there are plenty of modifications, proven modifications, that the engineers that you guys deal with seem to think there is some flaw with.

A bit back on topic:

Could you use documentation of what other people have used successfully, even if it is in a different country? Showing common modifications and how-tos from other sources, such as HybridZ, along with project threads where people have then driven their car for extended periods of time can show functionality and reliability, possibly along with safety.

I thought it was interesting that the engineer would suggest looking at other vehicles that used teh same bearings (why just bearings?) that used wider wheels to support a grey area in the wider wheel fitment category. In this vein, while I believe the bearings themselves are different, due to the races in the hub, the 300ZX (Z31) hubs do bolt right onto the S30 front spindles, I'm running a pair currently, to have the 5 lug bolt pattern. I also have the stock Z31 turbo wheels installed (16x7" http://www.az-zbum.c...and.tires.shtml).

#11 Dan260Z

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Posted 25 June 2012 - 01:54 PM


Dat240z - Sounds like I'll have to keep an eye on your progress as you're a few steps ahead of me, and thus I'm sure i could learn a few things!  Let me know some details of your brake set up and what your engineer says if you dont mind.
Also - what sort of wheels are you planning?  what has your engineer said about them?

Six_shooter - yeah I agree it's nuts here in Australia - I often watch shows like "street customs" or "american hot rod" and think about how difficult it'd be to do wild chassis mods, etc like that here unless the company employed a full-time VASS engineer! 
I think showing an engineer common mods, forum threads, etc would help to reinforce my case, but only just.  It may just help to get something that he's "almost" happy with, over the line.  Depends on the engineer too, they all have different interpretations.
Thank you heaps for the Z31 hub idea - if that's the case then I might start researching a 5-stud z31 hub swap!  If the factory wheels were as wide as 7", I'll be able to fit the 8" wheels I want legally.
What sort of brakes are you running?  Got a build thread or some pics of the set up?

#12 dat240z

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Posted 25 June 2012 - 06:47 PM

NO problems..... I actually have engineers tommorrow.

I currently run Performance Lotus 17x7 235/14/17 and its fine. Track is still 53inches in width which is what they are concerned most about in ACT. I did however purchase a set of gunmetal grey with polished lip rota rb's 17x7.5 to allow a 245 and they look better...

ill keep you posted.

Biggest issue with wilwood is no handbrake option so Woz helped me and let me use his rear spot caliper kit. Its top notch in design and a credit to him... Saying that Wilwoods are remarkable in braking ability so im happy with them

#13 sco_aus

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Posted 26 June 2012 - 10:52 AM

The most annoying part is that Wilwoods don't require dust seals, but the people making the rules don't actually know shit about what they are talking about.

#14 Dan260Z

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Posted 26 June 2012 - 10:11 PM

How'd you go with the engineers?  Hope it went well!  :)
Do they measure track from the centre of the wheels or outside?  ie. would wider wheels still give an identical track providing the offset were the same?

sco_aus, willwoods come in both dust sealed and unsealed versions, however the unsealed versions are more common as racers don't like dust seals due to them burning at high temps (so I'm told). But yeah, why the rules makers care about service life or rubbish like that I don't know.

#15 sco_aus

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Posted 26 June 2012 - 10:26 PM

Track is measured from the centre of the tyre.
Hmm, that's different to what I heard, but either way I don't see it as anything other than a maintenance thing, not safety.

#16 dat240z

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Posted 27 June 2012 - 10:21 AM

Ive got the AZCar brakes and am unsure if they are dust sealed or not....

Re:Engineering John Wilson was happy with the car, have a very low hanging sump not sure if its zr200 rear sump or rb rear one but its about 130mm off the ground and needs to be raised. Other than that brake tests next where they do a series of 100km stops and then should be sweet. Hope rego ACT are as casual as the engineer.

Even Wislon agreed the Wilwoods were a quality brake and thought it was stupid the non ADR applied as they are a far superior brake system to a lot of others..

#17 sco_aus

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Posted 27 June 2012 - 10:32 AM

I hate to break it to you, but John Wilson has been in trouble a lot for that casual attitude.  He tends to be a little too leaniant and then Dickson have a WTF moment.  You might be fine, hopefully, but his work is questioned a lot. I used him years ago and was fine, so here's hoping.

#18 dat240z

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Posted 27 June 2012 - 10:48 AM

Nah its fine, no new info thre. I cant believe how cas he is in person though..... The cars built well and with no chop up parts or old stuff so itll be fine.  Plus a very good freind is pretty high up at Dickson inspections so fingers crossed he will assist if needed.  Biggest thing i was worried about was track width with 235's and coilovers but its still the stock 53inches...

#19 sco_aus

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Posted 27 June 2012 - 11:18 AM

ahh cool.  yeah he barely even glanced at my seat rails and they were pretty dodgy at the time, still passed it lol, though Dickson didn't even look at it.  I would imagine the less offset, the closer to keeping the standard track (+13 offset i think).  The weirdest thing though is that you can't go even 1mm less track, but you can increase the track by 25mm, it is surprisingly easy to reduce the track when playing with wheel offsets. 

#20 Dan260Z

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Posted 27 June 2012 - 12:48 PM

Good stuff dat240z... shame about the sump though - which engine mount did you use?  hmmm... I wonder if I'm going to encounter this problem fitting an RB25 with teh castlemaine rod shop mount kit (with a jap RB20 sump)...

So did he mention anything about the wheels?  No issues with the width?  or did you have to prove to him that zeds came out with wheel's close to that size, etc?  Did you have to show calcs proving the diameter was within limits relative to the factory items, etc?

Sounds like you guys have a second inspection you have to pass (dickson?).  In Vic I believe it's just a case of getting the eng cert, roadworthy cert (easy, more maintentance focussed), fronting up to vic roads with those bits of paper in hand, they check the numbers on the car (VIN, etc) match the paperwork, and that's it.

Guess it doesn't really matter if the engineer is more lienient - it's his risk once he puts a signature against it.

Hmmm... I'm going to have to measure up my factory wheels (4.5" steel spare and 5.5" nissan mags) to see what the offset was - I'm hoping to run a +0 offset, 8" wide wheel to fill out some flares I'm making.  If the standard track was based on a +13 offset I might be in trouble...






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