Jump to content

Del Sol HC questions

FF lotus

Recommended Posts

Is laying the main hoop back a small angle legal ? Unfourtunately while looking into having one built for a customer we realized the only comfortable seating distance put the main hoop directly against the drivers helmet. The seat is as low as possible while still providing visibility for the driver but it's not enough


this cage is a drag racing design but you it gives the idea of where and how much




also is the car considered illegal if ran without the t-top and though it may sound silly would running with the rear window retracted provide relief for air pressure or disturb airflow across the trunk ?


Oh and I asuming a cage can be built which does not protrude through the rear glass area ?


Can I go through the trunk wall for bracing ?


I understand this question was asked by my customer on the Honda-Tech forums and quickly locked by a mod who said this had been covered when in looking through old topics it clearly has not soif someone could take the time to think about these questions that would be great. - thx

Link to comment
Share on other sites

15.5.11 Rear Braces

The main hoop must have two (2) braces extending to the rear. The braces shall be attached as near as possible to the top of the main hoop, and no more than six (6) inches below the top. The braces must not contain any bends. There must be at least 30 degrees between the plane of the main hoop and the plane of the rear braces. The main hoop rear braces shall be installed to form no more than a one hundred five(105) degree angle or no less than a seventy (75) degree angle with the main hoopwhen viewed from the top. The main hoop braces may be mounted at the rear shock mounts or suspension pickup points (providing that the braces remain in compliance with all other sections of the CCR). They may go through any rear bulkheads provided the bulkhead is sealed around the cage braces.

15.5.11.A Rear Braces - Exceptions

On cars where the rear window/bulkhead prohibits the installation of rear braces (Porsche 914, Pontiac Fiero, etc.) the main hoop must be attached to the body by plates welded to the cage and bolted to the stock shoulder harness mounting location. There must also be a diagonal bar connecting the top of the main hoop to the lower front passenger side mounting point (“Petty bar”). Some cars built for racing in other recognized sanctioning bodies may be granted a waiver of this rule, however they must show proof of compliance with the current published rules for their class.

That is copied out of the NASA CCR section 15.5. HC rules add in the case of the del sol that you are allowed to remove the rear window glass to permit rear bracing of the main hoop.


You need to dig a little to find main hoop specs. NASA roll cage requirements are nearly the same as the other guys (scca) with regards to IT cages. Their roll cage definitions are more precise. The maximum main hoop layback is 10 degrees. Any more then that, even though it doesn't say so in our CCR's, the main hoop most likely will not pass tech.

Link to comment
Share on other sites

Thanks for the response, I am aware of the allowance to run through the rear window and into the trunk but I wish to skip this as it obviuosly lessons visiblity and makes the car a high stop probability and occasionally I may want to drive it locally for fabrication work ect and I need to keep the car streetable as required by my current lease, since it's a long term project I may take possesion of the car altogether


Also how do I get a waiver for the petty bar - This would make instruction for him nearly impossible.


does the above picture seem to be 10 degrees ? I'm not good line of sight for that kind of thing and that design seems to give just enough clearance to be safe while allowing me to go into the stripped roof cavity (no roof vinyl but all intact metal) for a better fit closer to the roof outlines



Link to comment
Share on other sites

I am unable to veiw the above pic for some reason. Can you post the link?


You will not be able to have a race legal cage without the petty bar and without rear braces. You need either one or the other. They serve the same purpose and they are very necessary. Here are some pics of my del sol and the cage I installed in it.






This car is of course a deticated racecar. I have removed the rear window glass and its mechanism, as well as the trunk lid hinges to facilitate installation.

Link to comment
Share on other sites

I would think you pretty much have to put the rear bars through the window to meet to min agnle requirements for the rear braces.


Running w/o the roof is fine, though the driver will need to wear arm restraights. You will probably get better top speed w/ the top in place though.

Link to comment
Share on other sites

the HC rule book says through the rear window is an option so I'm assuming it's not the minimum


But either that or the petty bar effectively ruins the car as either a streetable car or one with room for an instructor. I was hoping the rear bars could be to and not through the trunk wall while a lower brace could run from the harness bar through the trunk wall and to the strut area's


I don't think running topless was an option I was just curious about legality


This car is'nt going to be a commuter car by any means but on days where events are held locally at cal speedway it would be nice not to have to tow it I'm sure


Anyway hopefully I will get a HC rule guy in here to allow it. I have worked up a design that is very reinforced and hopefully stiff so it's not a matter of weight but more for a matter of usability for the owner.


I thought this was also the way the Killer B team had there cage for the Motorola Cup ?

Link to comment
Share on other sites

For the cage to be legal for competition per the CCR, you will need to run either the petty bar or have the rear diagonals (braces). For the rear diagonals, I don't believe you will be able to get the required min. angle & be close enough to the top of the hoop without going thru the rear window &/or trunk.


The reason there is an allowance for the del Sol to run with lexan, or no rear window at all, is that it is a non-H1 car. Usually, these cars (H2-H5), are required to run a rear window made of glass without any holes or openings.


You will need to follow the rules, as laid out, in the CCR in order to run the car in comp. with NASA. Even if you only set it up for HPDE, I would be careful on how you did the rear braces. It might not be legal/allowed to run without proper bracing.


To be clear, the above statements are made as the NorCal HC Group Leader & a member of the rules committee.



Link to comment
Share on other sites

Man...there is not much room in there. Why is the harness bar so far forward, and where is the diagonal brace in the main hoop. That cage would need a lot of work before it would be NASA legal. Those rear braces look too steep to me...

Link to comment
Share on other sites

like I said that is a pic for a drag race design ie no diagonal and swing out door bars


I was only using it as an example for the main hoop layback.


The poisition of the harness bar is about 4 inches behind the seat and probably _ to the harness releifs in the seat. It is a rather small area though lots of leg room not alot of head room, with the stock seats and a helmet on my head almost hits the roof

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...