Hi. Newbie here. What are the key points to enhance rigidity of the chassis and rear suspension?

Can you take a picture of the mounting point where your support tubes touch the rear deck? I'm looking to do the same and want to ensure there's enough room there. Thanks!

 

What's the thinking of seat back braces? Can you integrate it into the main hoop or should it be a separate piece like what Brey Krause sells?

 

Doing a cage right now. Worked on it some today.

My rear upright going right on top of rear shock mount.

Hoop supports rear bars must be minimum 30 deg angle.

T

 

No, you can integrate it.

Only required for expired seats though.

I have an Autopower bolt in cage if anybody peeps in here and is interested.

Acid primed, single stage Alpine White....indexed for reassembly..., bolted in and never used. Was removed today.

T

 

Thanks T. Any tips for how to integrate it？. Pictures you can post?

I'm only planning for a roll bar for DE and am planning on the following mounting points: 1) just behind the B pillar on the wide sill 2) the front corners of the hatch floor, right on the frame rail. I'll double check that the stays and main hoop are at least 30 degrees.

On the sill - is a plate on the horizontal surface of the sill enough or should a vertical plate be added?

 

Only a plate is required. I was looking at doing a vertical from the rear seat crossmember but undecided and I'm a ways from getting permanent. Just started yesterday really so my goal for today is to just tack hoop on some throw away temporary 3/16 plate, all in position just to pull measurements for my software to create either a 1 piece halo or the conventional side bars.

I have canted main hoops in the past but going straight 90 deg vertical this time.

From 2017 PCA Club Racing rules - "The braces must be mounted as
near to the top of the main hoop as possible at an included angle of at least 30 degrees. Also, the assembly must contain a diagonal
(left to right side) tubing brace from one upper side of the main hoop to a floor or unibody lower frame mounting point of a bar
member on the other side to obtain the strength benefits of triangulation."

T

 

Here is a better picture of how the back brace is tied in on my car, structurally it is in a fairly strong structural location. This also shows the seat brace bracket.

Let me know what details you would like to see and I will try and get them for you.

 

Bob - thank you for the picture and offer. I hope you're doing ok in Houston.

My roll bar for my street / DE car will essentially use the same 4 mounting points as the rear of your cage does: b-pillar sill and front of rear hatch floor on the frame rail. Since mine is a street car, the roll bar's feet will have plates that BOLT ONTO plates with captive nuts welded onto those 4 chassis points. Because it is a bolt-in bar, and thus less stout than one welded to the chassis, I want to be extra careful how we design it.

This design with the 4 mounting points close to each other should make it easier to remove / install through the passenger door opening. However, I need to see if the mounting points are at least 30 degrees off the top of the hoop. Even if they are, I might still have an extra pair of "slip in" and bolt in stays that span from the top of the hoop to the rear "triangles" that are in the middle of the hatch floor, also on the frame rails.

My builder did suggest a rearward bend for the horizontal tube of the main hoop to allow the seat to slide back and make ingress / egress easier, especially since I plan on using a halo seat. Are you happy you went with that bend?

As for a seat brace integrated into the roll bar, is there any way to add a tube to the main hoop that would negate the need to add a seat brace such as yours? I'd like to do this for both the driver and passenger as I'll have instructors in the car.

Thanks for your help...and patience!

 

You do not need the back brace if your seat is under 5 years old. As most of the people who club race try to pinch as many pennies as possible, they run their seats past the 5 year date thus the need for the brace. As long as the seats are new no problem.

 

I allowed for it when I built mine.. Simple.. and i Ran a Straight up Hoop and and a secondary bar for the Door bars.. Hard to see because I got blue paint on the main hoop , But I was still in the process of "Fitting" when I took the pic.