Board logo

Weight issues
liftarn - 4/5/07 at 08:45 AM

I'm now much into the one seat design, but that has left me with a rather odd problem. Becasue of the local rules and the engine I have the car must weigh more than 720 kg and with a single seater it become too light.

Just to give an estimate, the chassis and bodywork will probably weigh slighly more than half of a standard Locost, the engine and gearbox are probably a bit heavier (it's a two litre after all), no propshaft, suspension abut the same. What would I end up whith?


iank - 4/5/07 at 08:52 AM

Wild guess of 500kg+/-50kg


Doug68 - 4/5/07 at 09:13 AM

I doubt it'll be 50% lighter than the the book Locost chassis, also the book chassis wasn't the ever stiffest in the world.
So build good and strong - stiff and if its still too light bolt in some lead.

Thinking about the things you might run into in your part of the world I came up with:

1. Volvo's.
2. SAAB's.
3. Elk
4. Tree's

I'd build it strong

I've heard of LandRover bolting weight in too in some markets as 'light' vehicles get more import duty than 'heavy' ones. That may be an urban myth though.


BenB - 4/5/07 at 09:15 AM

Is that weight needed solely for registration or will it be tested at a later date as well?

If it's just for registration can't you fabricate a rather OTT roll bar system and fill it with lead shot then take it off afterwards and replace it with something more sensible?

I'd suggest sheets of pig-iron bolted to the bottom of the car but I think that might get spotted!!

Can't think how you'll get a single seater to be >750kg otherwise unless its ridiculously over-spec'd.


iank - 4/5/07 at 09:34 AM

I've heard lead shot also makes an excellent anti-surge filling for fuel tanks though you wouldn't want to leave it in too long if you have a cat-converter

3mm steel floor rather than 1.5mm aluminium might also be prudent until you get used to the handling.

Donor steel wheels might only be replaced by lighter alloy ones after the registration inspection for cost reasons...


graememk - 4/5/07 at 11:36 AM

fill the tyres with water lol

and carry 4 spares as well


02GF74 - 4/5/07 at 01:35 PM

quote:
Originally posted by graememk
fill the tyres with water lol




not such a carzy idea as you may think - tractor drivers and off-roads do it as it lowers the CofG.

I am sure with a bit of imagination you can bolt on some weight;


akumabito - 4/5/07 at 02:21 PM

Simple solution would be to just use a ridiculusly heavy engine... Jaguar V12 springs to mind! 300+ kgs for just the engine...


liftarn - 4/5/07 at 03:16 PM

The weight is only needed for registrations, but they aren't stupid. Lead bars bolted on will be very difficult to explain. Using a full tank will add an extra 60 kg or something.

The SAAB 900 engine is quite heavy. The transmission something like 50 kg and the engine about 150-170 kg.

If it was weight including driver it would be easier.


gttman - 4/5/07 at 03:46 PM

weld steel panels to the entire chassis, this will stiffen it up a lot.
Adding weight to the chasis to strengthen it will be one of the most productive ways of adding weight.


akumabito - 5/5/07 at 01:04 PM

Isn't it just allowed to have ballast on board? Some racing classes have a minimum weight to compete, meaning that cars are all ballasted to the same weight before the race. I can not imagine them making a big fuss about blocks of weight.. hell, you could even position the weights to aid in proper weight distribution..


liftarn - 6/5/07 at 12:33 PM

I don't have the exact regulations available right now, but it probably says something that it has to be of permanent nature and non trivial to remove. It says something simmilar about detuning the engine too so I can't just disconnect the turbo and lower the power.


Doug68 - 6/5/07 at 01:53 PM

My thoughts are that maybe you should go back and look at the regulations again.
If the authorities are serious about the regs then you'll need to find the type of vehicle that works best inside the rules & maybe a single seater isn't it.

Given the engine you plan to use how does it work? Is it a power to weight thing or more complicated than that?


Ringius - 6/5/07 at 09:06 PM

I assume that liftarn is speaking about the swedish SVA regulations, that stipulate that you are not allowed to have more than 15kW per 10kg of weight. Weight is measured with all fluids, spare tyre and approx 10kg of tools.

In addition to this, the power of the engine is regarded as being the one stated in the registration papers of the original vehicle - thus no possibilities of de-tuning. I guess the "normal" procedure is either to tune the engine after registration (not really legal, but difficult to show/prove) or use one engine for registration and another one when acutually using the car - of course not legal either, but fairly common...

Suppose that should have been 15kW / 100kg, otherwise it wouldn't be a problem, now would it?


[Edited on 6/5/07 by Ringius]


violentblue - 6/5/07 at 10:29 PM

I'd add some bolt on false bottom rails to the chassis filled with lead, put a textures undercoat over it do it looks permanent, then when no ones looking, take em off.

[Edited on 6/5/07 by violentblue]


liftarn - 7/5/07 at 08:30 AM

Yes, 15kW / 100kg. It used to be 10kW / 100kg making sevenesque builds very tricky.
I could use a less powerfull engine (like the 118 hp injected 8 valve or 126hp 16 valve injected) and legally change it afterwards as you are allowed to do an engine swap on a registered car. But then you'd have to stay within a 20% increase in power (I think). It would mean more work and more money (in fees if nothing else).


thomas4age - 9/5/07 at 02:23 AM

If all this is true, How can it be that Majoola (apperantly swedish) build an Ultima GTR with a lexus 1uzfe Twin Turbo engine with 928hp at the wheels, and got that registered? (or was he from finland?)

look up the best power to weight ratio you can have and build that,
or build a very High Torque Low reving engine and start from there....

diesel middy (aka 1.9 TDI powered spire GTR or something) KW stays down Torque is key... should be a very fast car, and the diesel engine weigh in a tad havier then the petrol potters so that's a + then... hmmm idea!

ps the old rule you had: would only let me have 49.8KW in the striker..... that;s not fair!

grtz Thomas

[Edited on 9/5/07 by thomas4age]


Ringius - 9/5/07 at 09:55 PM

I can assure you that you cannot register an amateur built car with that power in Sweden, unless you are cheating one way or another...


liftarn - 10/5/07 at 07:10 AM

Was it road legal? It could have been imported. If it was registered in the UK first and then brought to Sweden and given swedish plates it could be possible.

It's better with three wheelers, they can be registered as motorcycles and they don't have any limits.


thomas4age - 11/5/07 at 07:20 AM

Yes It was SVA'd in the Uk and then brought to scandinavia iirc.

I didn't know you had any form of aproval in your own country, that's even better than holland, we always go to Uk first.

grtz Thomas


liftarn - 14/5/07 at 06:51 AM

quote:
Originally posted by Ringius
I assume that liftarn is speaking about the swedish SVA regulations, that stipulate that you are not allowed to have more than 15kW per 10kg of weight. Weight is measured with all fluids, spare tyre and approx 10kg of tools.



And don't forget that it also includes a 75 kg driver. I don't really see where I could fit a spare tyre in a single seater, but that would help.


dr-fastlane - 16/5/07 at 05:48 AM

Thomas4age: Yes there is such a thing in Holland. Only for scratch build cars, not kit cars. That’s the way I do it


liftarn - 16/5/07 at 11:05 AM

Then it's the same in Holland as in Sweden. Sweden has no rules for kit cars, only for scratch built cars, but there is a gray area between a kit and a scratch built. You are allowed to buy a chassis and body parts and it will be seen as scratch built if you source engine, gearbox, interior et.c. yourself. A full kit with everything included would not work. So a key ready is out of the question and a rolling chassis doesn't work either. If you buy a half built car you basicly have to disassemble it and rebuilt it. Well, you probably have to do it anyway. An anateur built car in Sweden has to be inspected three times. First when you reached the rolling chasiss stage. Then they inspect the design, check for bump steer and check the quality of the welds (so you're not allowed to grind them down or paint the chassis so if you want to paint the chassis you probably have to disassemble it, grind down the weld seams, paint it, and reassemble it). Inspection two is done on the finished car, checking noise levels, braking, lights and so on. The third check is just a regular MOT.


Schrodinger - 16/5/07 at 11:52 AM

You could use a standard 1.8 Zetec which would give you 115bhp and then put 2.0l cams and plenum/ throttle body on after registration to give at least 130 but upto 150 if using an aftermarket ecu. But I'm not sure if this is that accessible for you.


quote:
Originally posted by liftarn
Yes, 15kW / 100kg. It used to be 10kW / 100kg making sevenesque builds very tricky.
I could use a less powerfull engine (like the 118 hp injected 8 valve or 126hp 16 valve injected) and legally change it afterwards as you are allowed to do an engine swap on a registered car. But then you'd have to stay within a 20% increase in power (I think). It would mean more work and more money (in fees if nothing else).