Lotus Elan

Interpreting MSA rule book

PostPost by: stevebroad » Wed Mar 25, 2015 10:02 am

Anyone out there use this book? I am trying to understand the rules re roll cage tube sizes.

Car is a 1967 Lotus Elan. I plan to use it in Street Class drag racing, sprints and hill climbs. It will be a hardtop. The regs seem to indicate that I can get away with just a hoop of 45mm diameter - 1.6.1 (c)

My question is - I want to fit a full roll cage as we need to stiffen up the chassis as it is as stiff as a strip of liquorice, even when modified to 26R standard. So, does the additional tubing have to also be 45mm diameter or can I use 38mm as I would class these tubes as optional? I plan to use T45.
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PostPost by: Spyder fan » Wed Mar 25, 2015 10:21 am

Steve,
Not sure if this brochure will help you? It does mention optional tubing can be 38mm, but seems to be referring to particular designs of roll cage where optional extra tubing can be added.

153191commonregulationsforcompetitorssafetyk.pdf
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PostPost by: rcraven » Wed Mar 25, 2015 10:29 am

It can sometimes be difficult (partly because of the need to cross-reference one section with another) to distinguish between what is compulsory and what is recommended.
Why not just ask the MSA directly?
Robert
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PostPost by: toomspj » Wed Mar 25, 2015 12:45 pm

I think you'll find the roll cage is specifically regulated not to significantly improve chassis stiffness.
The Safety Devices full cage used by most competitors does very little in this respect.

A lot if us race Elans with considerable success against much more powerful cars. I use reasonably high spring rates (375# front) and it works for me.

If you want stiffer why not go for an Exige?

Paul
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PostPost by: stevebroad » Wed Mar 25, 2015 10:39 pm

toomspj wrote:I think you'll find the roll cage is specifically regulated not to significantly improve chassis stiffness.
The Safety Devices full cage used by most competitors does very little in this respect.

A lot if us race Elans with considerable success against much more powerful cars. I use reasonably high spring rates (375# front) and it works for me.

If you want stiffer why not go for an Exige?

Paul


Thanks for the prompt response, Paul

Yes, that is why we are building our own.

The standard 26R spec chassis (or one built to this spec plus more) is fine for normal power outputs but my chassis will have to deal with over 500bhp.

Because I have an Elan (and had it for over 40 years) and don't like Elises or Exiges, not my era :-)

Steve
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PostPost by: stevebroad » Wed Mar 25, 2015 10:40 pm

rcraven wrote:It can sometimes be difficult (partly because of the need to cross-reference one section with another) to distinguish between what is compulsory and what is recommended.
Why not just ask the MSA directly?


Thanks Robert, that is a very good idea, I will do that now.

Steve
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PostPost by: stevebroad » Wed Mar 25, 2015 10:44 pm

Spyder fan wrote:Steve,
Not sure if this brochure will help you? It does mention optional tubing can be 38mm, but seems to be referring to particular designs of roll cage where optional extra tubing can be added.

153191commonregulationsforcompetitorssafetyk.pdf



Thanks Alan. This is the section that I am struggling with. As suggested by Robert, I am about to ask MSA directly.

Steve
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PostPost by: ecamiel » Thu Mar 26, 2015 12:25 pm

Pre roll cage days we turned the ?lan into go carts with spring rates around 325 plus front, 200 plus rear, 1 inch or 7/8 front bar, 3/8 rear bar.
Much of the chassis stiffness comes from the body. Peter Pulver's 26r was actually faster after it was rebodied with a street body rather than the lightweight one. Much of the flex is in the horizontal plane, not twist. Btw, the dash is a major structural member.
Some people, not me of course! Used unidirectional carbon fiber reinforcement to stiffen the body and thru bolted the bobbins.
Now all this is irrelevant foe cars whith tube frames disguised as roll bars.
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PostPost by: stevebroad » Fri Mar 27, 2015 6:53 pm

ecamiel wrote:Pre roll cage days we turned the ?lan into go carts with spring rates around 325 plus front, 200 plus rear, 1 inch or 7/8 front bar, 3/8 rear bar.
Much of the chassis stiffness comes from the body. Peter Pulver's 26r was actually faster after it was rebodied with a street body rather than the lightweight one. Much of the flex is in the horizontal plane, not twist. Btw, the dash is a major structural member.
Some people, not me of course! Used unidirectional carbon fiber reinforcement to stiffen the body and thru bolted the bobbins.
Now all this is irrelevant foe cars whith tube frames disguised as roll bars.
Eric
64 S 1/2


I have compromised the structural stiffness of the body by cutting away the passenger sill so that a side exhaust could be fitted (long story but basically this was the only was to get the 3" exhaust away from the pedals and leave some ground clearance).

We are producing over 500bhp (near to 600 with racing fuel) so there is way more torque being produced than ever imagined when the car was designed so extra stiffness is vital.

Steve
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PostPost by: stevebroad » Fri Mar 27, 2015 6:55 pm

Received a reply from MSA but they obviously didn't read my questin properly as they simply quoted the section I was asking about!

Replied, spelling out my question again but in shorter words so hopefully I will get a useful response this time.
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PostPost by: Spyder fan » Fri Mar 27, 2015 9:11 pm

DISCLAIMER: I don't compete and I have never built a car for competition, frankly I don't know what I am talking about, but I am good at reading gobbledegook and making sense of it, whether I am right is another question..... Proceed with caution, but I hope this helps.


The Msa regulations for modified production cars allow reinforcing of the chassis

See page 331 https://www.msauk.org/assets/2014msayearbook.pdf

Fabricating and fitting a roll hoop or other cage as required for your class with additional members to assist reinforcement of the chassis doesn't appear to be a grey area. Providing the main structure is constructed of the tube diameter required and fixed to the points required then the supplemental tubes can be 38mm.

However I would suggest you talk to other competitors or the club that runs the series that you want to compete in. Remember that you have to get the car past the scrutineers, and each series seems to have its own little regulations.
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PostPost by: patrics » Sun Apr 26, 2015 8:13 am

Hi Steve
If it helps you can have my old blue book.

Regards
Steve
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