985cc Turbocharged Nova Sprint Car

I'd say they both contribute stiffness to a very beneficial part of the car myself, and they could be removed but the weight gain against what you may lose in camber stability (which on a mac strut is obviously far more important than double wishbone) would make it a step backwards. Couldn't say for sure either way without a load of telemetry gear or at least an FEA setup though lol

Me and Colin were talking about removing stuff off of the doors at nats, pretty sure the seals came up, as did replacing the lock mechanism with suitable magnetic catches :d

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Originally Posted by dhdev (Oli)

The one that goes diagonally down at the front terminates very close to the floor, so the the moment from the floor to the mount point would be minimal. So this one could definately be removed IMO. I'd imagine the tube stiffness would make the top one redundant also IMO.

The shell has been lightened already by the removal of seat mounting brackets, so are the regs slightly flexible, or is it a matter of what goes unoticed is ok? Also door/boot seals aren't technically the shell, so they could be ejected.

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Yes, I could remove some tubes from the rollcage, if I get to the desperation phase.

Strictly speaking, by my interpretation of the rules, the seat brackets should not have been removed (except where they are in the way of correctly mounting a seat).

I will check that point with an MSA Scrutineer at the next meeting, as I might have to reinstate those. You can guarantee someone will start protesting if (when!) I start winning with it.

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Originally Posted by MK999

I'd say they both contribute stiffness to a very beneficial part of the car myself, and they could be removed but the weight gain against what you may lose in camber stability

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Camber stability? Possibly via some form of castor change reduction, as they only brace in the longitudinal direction, but I'd wager that the deflection even without forward triangulation would be less than a couple of mm, and you'd be hard pressed to notice the tiny affect on castor and subsequently smaller variation in dynamic camber. To be honest I'd imagine the only benefit of having the forward triangulation is during a heavy dead-stop crash, as you'd get in rallying.

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Originally Posted by MK999

Me and Colin were talking about removing stuff off of the doors at nats, pretty sure the seals came up, as did replacing the lock mechanism with suitable magnetic catches :d

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Liking the lateral thinking on the catches :thumb::d

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Originally Posted by MK999

Try and find his saloon WIP on mig, as he's normally on there more often I believe.

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I've already put up a couple of posts on his 'Project' thread on PNG, but no response from that.

If anyone knows Austin Nova16, perhaps they could ask him to contact me?

I hadn't realised he had a thread on MIG, that will be worth a try, thanks.

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Originally Posted by dhdev (Oli)

Camber stability? Possibly via some form of castor change reduction, as they only brace in the longitudinal direction, but I'd wager that the deflection even without forward triangulation would be less than a couple of mm, and you'd be hard pressed to notice the tiny affect on castor and subsequently smaller variation in dynamic camber. To be honest I'd imagine the only benefit of having the forward triangulation is during a heavy dead-stop crash, as you'd get in rallying.

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It's surprising how much it all affects it, I've just spent quite a while on FEA developing simps chassis, and believe me those bars will add to the camber stability, and a couple of mm is the size of your average camber shim.

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Originally Posted by MK999

It's surprising how much it all affects it, I've just spent quite a while on FEA developing simps chassis, and believe me those bars will add to the camber stability, and a couple of mm is the size of your average camber shim.

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But those bars brace in the longitudinal direction, so castor. This would obviously help dynamic camber, but 2mm (arbitary number) of castor at the top of the strut, would be a negligible increase in castor angle and hence virtually un-measurable dynamic camber change.

CDS bars don't have a negligible strength across their cross section though, it doesn't 'just' brace in the direction of caster change.

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Originally Posted by MK999

CDS bars don't have a negligible strength across their cross section though, it doesn't 'just' brace in the direction of caster change.

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But at a length of 50cm (ish) from the main-hoop mounting, the moment at the strut will surely be large enough to make the stiffening minimal. Not only is there the bending of the forward protrusion, but also the torsion on the cage front leg.

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Originally Posted by dhdev (Oli)

But at a length of 50cm (ish) from the main-hoop mounting, the moment at the strut will surely be large enough to make the stiffening minimal. Not only is there the bending of the forward protrusion, but also the torsion on the cage front leg.

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True, but it all adds something, and once you get down to the kinda minute deflections a car like this has, those tiny additions mean a lot.

There's an area on simps chassis which is braced entirely in the wrong directions due to where the gearbox sits being in the way of proper bracing, and 2 bars loaded in a very similar way to these dropped the deflection from 5mm to 1.2 purely by repositioning them.

It's not the best way to brace that point, and the strut brace may well render it near useless due to its 'actual' stiffness being much higher, but it's not something you can just look at and say that can be chopped out imo. I think it has more benefit in being there than you're implying, just my opinion and I can see where you're coming from in suggesting it's removal :)

Small update, all on a weight saving theme.

I acquired these for £2 plus postage off EBAY;
http://i285.photobucket.com/albums/l...cort/002-8.jpg

A set of lightweight door catch pins! Now fitted, after a bit more lightening was done to them, they work very nicely and save 250g!;

http://i285.photobucket.com/albums/l...cort/003-9.jpg
http://i285.photobucket.com/albums/l...cort/004-8.jpg

I've also replaced the plastic vents in the door pillar with carbon fibre sheet to save a little bit more.

I am now gradually working round the car and replacing any non-stressed nut or bolt I can find with alloy or titanium, after buying a bumper box (another EBAY find);

http://i285.photobucket.com/albums/l...cort/005-9.jpg

I'd already replaced just about every bolt on the car with aluminium, but most of the nuts were still steel until these came along.

Next week I'm off to see an engineering company who can make me a rear beam in titanium (!serious!), which they reckon will be around 4kg.

The standard bare rear beam, (i.e. WITHOUT the brake drums, anti-roll bar and stub axles) weighs in at 14.5kg, so that would be a really significant saving.

And the same engineering firm can also make me some 8" x 13" split rim wheels which weigh in at 3.6kg each, which is a massive reduction on the 8kg or so of a Compomotive MO. And I love the look of them too;
http://i285.photobucket.com/albums/l...wheels-red.jpg

Must check my lottery numbers..........