I think I have made the decision to build a new chassis for my car. Having built the car some years ago, there is nothing really wrong with it but I can now see lots of ways of improving it and now have the skills to do it. I want to tidy up all the little things and it could do with a general body tidy up.

I am going to keep everything other than a new nose cone to go back on the car. It will have new ally sides and back, and I suppose other than the running gear it will be a new car. I am going to make a slight difference to the chassis width as well.

Myself and another builder friend will only take a weekend to make the chassis. Once completed it will need to be painted and fully wax oiled.

As the existing car is on the road I can spend lots of time after it is built preparing it for the parts swap.

As I never documented the original build, nor did I take that many photographs I think I amn going to video the chassis build over the weekend we do it and take lots of pics.

I am after a relly good and hard paint to finish it in. Any ideas?

I also want to etch prime the chassis, any ideas on that to.

Any ideas and questions would be good.

take a look here
http://www.frost.co.uk/cat_menu.asp?catID=55

Build a complete chassis in a weekend.... Man i must be slow, its taken me months to complete, i mean fully complete my chassis.
Best of luck and look forward to video and pics.
Cheers

Hi Refurb,

Welcome back to being a locost builder as opposed to driver!

Just out of interest, what did you paint the chassis with originally? And how has the coating survived the years?

Thanks,

James

It was originally primed and sprayed then baked in an oven. Came out very well but with stone chips underneath and holes drilled here and there it has seen some action.

I have today re measured and ordered the steel. We will start next Friday and build the basic chassis. Then on Sunday take a trip to Stonleigh and buy front suspension brackets and probably some stainless nuts and bolts. Depending how Friday goes will probably cut out the bottom sheet and all the transmission sides in steel and fully weld.

As we stood there today it was quite exciting. We went through the book and between us came up with the natural upgrades you either need or should do to make it a better job, and more easier to maintain. We agreed ours had been like prototypes over the past few years. So now we have a good drive train and proven system it just needs tidying up.

Videoing the chassis build and then editing it down to a DVD should be good?

I am unsure about what paint to use on the chassis. I think etch primer and then a two pack heavy spray job again. But I keep hearing about these fantastic rust primers. Not totally convinced it needs it. Defo on wax oil in the chassis this time. As well as sealing it I am going to weld a nut onto the chassis points so a bolt can be removed to re waxoil every year.

As you are doing this exercise to improve the chassis- have you studied Cymtriks' chassis upgrade designs?

He's done some Finite Element Analysis of the chassis and basically his mods can double the stiffness without a weight penalty. Interesting stuff!

HTH,

James

Here's a copy of Cymtriks' mods:

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Here's how to improve the torsional stiffness of the chassis by 100% and reduce weight by 10%.

Add a V brace from the bottoms of tubes LA and LB to the middle of tube LCchecking for clearance with the radiator and fan assembly. Weld in a panel between tubes E and LD. If you have room with your chosen engine duplicate tube R on the other side of the chassis. Add diagonals from the bottom of tube FU1 to the top of tube LB and from the bottom of tube FU2 to the top of tube LA checking for clearance with the steering rack. Weld in a top panel to the transmission tunnel from tube O3 to tube P checking that access to important nuts and bolts is not too restricted (a local access hole is fine). Delete tubes i, j, k, c, d, g and h leaving a tunnel composed only of sheet steel except for the base tubes. You may require a local reinforcement for the tunnel at the positions of gear lever and handbrake mountings. All steel tubes are assumed to be 1.6mm or 16gauge and all panels are assumed to 1.2mm or 18gauge except for the reinforcement around the suspension and seat belt mounts.

In case you are wondering these mods move the lowcost chassis from a stiffness in the region of 1200 to 1500 ftlbs per degree of twist to around 2500 ftlbs per degree. This improvement is possible due to the fact that, except for Caterham, most seven type chassis are way off an optimum design and some would actually be better off, weight for weight, with a simple hot rod style X braced ladder frame.

In case you are wondering how I got these figures I make my living out of structural analysis and testing and have access to the same computer analysis techniques that major manufacturers use.

I hope that you find this interesting!
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HTH,

James

Yes I have and I had already added those to my existing chassis.

As well as those upgrades you can add ones that just help with the build and also help with general maintenance and ease of getting to places.

I think it all comes down to exactly what you are going to do with the car.

Road use means, add fully welded floor, trans tunnel and rear fire wall. Metal scuttle and decent roll bar.

Race means, make it light and use more ally.

If you smack it up on the track you will get attention in a minute. On the road you could have to wait 10/15 minutes.

Chassis strength is very important, but anything below 180/200 pounds of torque I don’t think you are going to damage it.

Looking at the new banshee, at first glance of the pics shown it appears to be a very light construction. Ideal for the track me thinks. My main concern whilst driving is side impact in the 7. The average bumper seems to be a few inches higher than my car, and I don’t like the idea of head butting a Mondeo at any speed.

I think side impact bars are a good idea. I may try to look at incorporating them into the new chassis look.

I think our posts crossed.

Like everyone else caterham drivers are always looking for more go.. They also get concerned with the chassis performance once you start talking about big power gains. I would still say 250bhp and 180/200 ft-lb of torque is capable on a well made chassis without going to mad.

I would say the average BHP figures on a caterham or Westfield are around 140 to 170 bhp. Torque around 130/140 The average weight of a caterham 575kilos.

There chassis design can only be described as adequate to do the job and not over engineered.

Cymtriks' mods are very informative and a real belt and braces approach adding both safety and an over engineered response to a problem that might not be there unless you intend running big power.

quote:

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Originally posted by Refurb
I think our posts crossed.

<snip>
and an over engineered response to a problem that might not be there unless you intend running big power.

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That’s a good point, but it does not make it right.

If it did then we would all build "bird cage Maseratis"

The "book" was the birth of the Locost, it is always easier to improve something once its been done.

I’m just saying do we need all the changes?

Well 42mtrs of box section arrived today, over ordered a bit me thinks, as well as a couple of mtrs of 40 x 40 box & a sheet of steel all for £75.00

Also ordered some POR-15 chassis primer an etch pimer £97.00 delivered.

The great chassis build starts Friday, finishes Saturday. Show Sunday.........