Panels rivets

[cherno]

I've build my haynes 4 year ago and I still make modification on.
My car is only used on track I try to have the a better car each time.
I want to share you experience about adding rivets on the side panel to enforce the chassis/frame rigidity.
I consider to add a lot of rivets even the aesthetic is not preserved.

Do you have commandations or experience to share on this subject ,

Thanks

[Badger]

Hi Cherno, assuming a standard Haynes chassis, whilst it would somewhat depend on what material your side panels are made from I would not think that riveting them would provide a large boost to chassis rigidity. Replacing the panels with welded in items or diagonals would provide more rigidity, but comes with a weight cost.

[flyerncle]

Changing the chassis spec ie tube wall thickness and replacing 19mm with 25mm is what will effect rigidity of the chassis and that was what was done to a chassis that was built by Saturn to be raced,2mm wall tube instead of 1.6mm and it was very rigid and handled well.

you may find improvements in suspension mods like spring rates and dampers,also anti roll bars or more drastic inboard suspension so the dampers work at a different angle.

[cherno]

Thanks for answers

About chassis change I'm not going to rebuild a chassis so I keep my 1.5 thickness tubes
I prefer stay light. If we change 20mm to 25mm we increase by 30% the weight
and for thickness changing from 1.5 to 2 is also 30% more.
The result will be a heavy chassis ( 40kg with 20 and 25 and 1.5 and more than 60kg with bigger tubes ).
A best choice if with consider to change the chassis will be to stay with 1.5mm and use rectangular tubes ( round one are more complex to assemble ) to increase size only where it give more rigidity but it's complex to make the right choice.

I have allow side panels, riveting then is a very light change even if it not give big difference it can't be negative. I've planned to add rivet each 5cm on tubes joining top and bottom of the chassis sides.

[cherno]

Here is my panel with some rivet



Full size image

[flyerncle]

You could also panel the insides,replacing the 19mm tubes with 25mm would not add much weight but as you say the chassis is built.

[cherno]

I've found this image on internet and this kind of tube can be a good choice if we consider to build a new chassis.

[TalonMotorFabrication]

Slight off topic tangent warning......
Instead of looking at how to save weight on the chassis by changing tube sizes and wall thickness I would be looking at all the other parts bolted to it. A chassis weighs between 55-80kg depending on 1.5-2mm wall tube but the difference between a Sierra front upright and a Mx5 upright is about 5-7kg, then there is the calipers can they be changed for say some thing such as Hispec full ali items, solid disks instead of vented saves another 2-3kg and so on.
People get so wrapped up in the major component that they forget about the sodding great lumps of over engineered cast iron and steel that they are bolting to the chassis. If your all anal about going light find an all ali engine with ali bell housing,calipers,panels,fuel tank and end up potentially spending thousands.....then take a look in the mirror and ask your self can I lose 20kg myself? My answer to power to weight ratio.......spend another £500-1200 fit a turbo or a supercharger and stop worrying about how much it weighs.

The Roadster chassis is quite strong along it's length so what you have done with the side panels has not added much to it, how ever it's not so good across it width. There is no direct diagonal across the chassis at it's mid point but you could join the sides together by means of the transmission tunnel, if you get creative with 4-5 tubes in this area instead of the whole chassis you can make the middle of the car stronger. The only real world limiting factor to how strong you make the chassis is the human body which is a engineers worst nightmare, it stops them from adding much needed diagonals to every thing.

[flyerncle]

The whole point of the thread was to add rigidity to the frame by an attempt to secure ally panels to the frame but all the comments above make sense,at the end of the day it's what you want out of it and the sum of what you put in is the end product.