Building your own road car from scratch

[AsleepAtTheWheel]

I've had plenty of experience with these cars - I own a Silvertop 20V Clubman that was scratch built. Although I haven't built one from scratch myself because I'm not confident in my welding abilities, it is possible to attain ADR's etc for a full custom job - you just need to be prepared to fork out the $'s and the massive amount of time it will take for engineering. Be prepared for lots and lots of setbacks and runarounds from Qld Transport - especially if you want to road-register it, and get in contact with a one of the Clubman builders groups. There is a forum and a few other message boards around that deal with Australian builds.

You also have to comply with emissions ADR's as well which limits your engine choice (4age's are no longer eligible - you need to go something like a Ford Duratec/Mazda Zetec engine which is built to the standards ). As far as I can remember, the only thing that they don't have to comply to is side-impact ADR's (which comes in handy when you're sliding toward a tree :blink: ) and they have a plate that states that.

You can build them perfectly on a pay-as-you-go basis. Trust me, unless you're welding together chassis full-time, there is no way you'll be able to put an engineerable frame together in your spare time in less than around 6 - 12 months. You'll have plenty of time to hoard parts, trade them, buy and sell as you want. Remember you have to buy and cut the steel, build the chassis jigs, weld the bits together, check, check and check again - and then you've got to have some form of engineered CAD plan to start with, with all your clearances, mounting positions, tolerances etc worked out. Then you can start thinking about suspension geometry/setup - and the physics involved in ALL OF IT... still sound like a good idea??

Body panels would have to be fibreglass, unless you know a really good metalworker/coachbuilder. Try to incorporate as many flat panels (or close to flat) as possible because then you can use thin gauge sheet ally which you can bend around corners etc also.

If you go down to Skelta and talk to Ray (Vandersee) or any of his guys, he'll probably be able to point you in the right direction and give you some idea what you're up against but be prepared to be shocked :lol: If you're still up for it - go banana's, but we'll all want to see updates!

[ae71]

i intend on building a simerlar thing, im aiming for 500kg's.

it would be a track car only. i would be using a ca18det becuase they are still resonably compact yet make more than enough power to be extreamly fast in a very light car. i would also be using more of a silvia suspension setup. im not sure if a hilux diff or an irs setup. pannles would be minimal, just around the cabin, and a front scoop to direct air to the cooler/radiator.

it would be nice to register such a beast but it would as have been stated it would cost too much to build one from scratch or register, hell building one like this is still going to cost 15-20k with a dirty old ca!

[AsleepAtTheWheel]

<div class='quotetop'>QUOTE (ae71 @ Nov 1 2007, 10:41 AM) </div>If you're building a track-only special, you have to make sure that you're eligible for a class (e.g. Marque Sports), then read and understand the regulations pertaining to the class otherwise you'll find yourself doing lap shootouts for time only. I don't know quite what your "track" aspirations are aiming for, but stuff like motorkhanas would be more suitable to what you're describing. Again, regulations become the bottom line. I'd hate for you to spend a year building a car only to have nowhere to compete. :blink:

When it comes to setup, research is your best friend. A silvia suspension setup will not work in the front end of anything like this mainly due to the large size of the struts and the arms etc. plus you've got to maintain the angles of the original chassis setup. I'd say that you'd have to have custom arms and use short-stroke GAZ style coilovers, this way allowing your chassis engineering (force distribution etc) to determine your suspension setup.

When it comes to rear end, a hilux diff is wack - just way too heavy, and you've got bugger all weight to move when it comes to launching so blowing a diff is not going to happen too easily. Lightness is your friend and there are heaps of lighter beam axle options (escorts are commonly used among others) and you can get plenty of tough parts for the internals easily plus to keep it cheap you've got to keep in mind your brake options. IRS is not a bad thing, but it all depends on your preference. I've seen a number of different setups including beam-axles, watts linkages, DeDion rear ends, IRS but there are none with a clear advantage over the rest. Reseach (again), drive some different setups and make your decision. If you go IRS, you can use any of the Nissan options - especially if you buy a CA Silvia as your donor car.

Also, you don't want a CA with it's tits tuned off turning out a fully hektik 300rwkw to power it. It will not only be a death machine, but it will be undriveable. In the case of these cars, there is such a thing as too much power - you can only use so much before the limits of adhesion/gravity/anything else are reached. Then you'll just be pissed off that guys in less powerful cars are lapping faster than you just because they've got better power-down and drive out of corners...

[ae71]

I agree with you,

As there are no real racing series in Tasmania I'm not doing it to compete in any class, mainly time attack and fun.

as i said i was considering and its going to be a long while before any construction begins. the reason that im thinking of a ca18 is they are obviously quite a bit cheaper than a sr and the idea is to get a reasonably cheap motors that makes ok power as is so that only light tuning to help keep it reliable and responsive. being the simerlar weight to the clubman but with more power really, i was told that it actually lacked a little in power. i was considering using a complete silvia front end, including x-member and lca's. I'll be completely honest and say i do not know much about silvia setups and this is part of the research that has to go into it before i get out the gas axe. also choosing the silvia stuff because sr brakes should be enough due to the car weighing just 2/5 of a Silvia. ill also have a lot of track and a shorter wheel base which should make it quite stable threw corners. it will of coarse have the centre of gravity as low as possible so i think it should turn quite well. one thing is i probaly want to see if i can mount the motor back further than on a factory cross member because this will end up with too much weight over the front wheels compared to it being in a car with more weight all around.

rear end, there are plenty of options, i do want something thats capable of exepting an lsd, dont want anything too aggrow in a light car or it will understeer/oversteer too much. it will come down to practicality availability and if im able to actually do it all myself. a beam rear would obviously be the easiest option maybe even being able to combine it with rear coilovers. one advantage of IRS is the ability to add a little rear camber. I think IRS maybe a little heavery though. maybe a r31 borgwaner with factory lsd (nice and loose) maybe an option, also has disk brakes as std. i think that apart from the camber adjustment IRS is even less necessary on a smooth track surface, i think you would need it for rally/offroad.

as i said quite a while off yet, have no room to undertake another project or money to do so.

[driftke70]

my dad recently finished building a lotus 7 replica with a black top sr20det and 6 speed and full torsion rear end and 2 way out of an s15, goes fricken hard as, crazy as when you slide it cause its like pendulum and swings you around. Handles magic.

Harder than you think to do, he built it from scratch by himself and took him about 2 years.