I've got to install a seat bracket before Cascade Lakes, otherwise I might not pass tech inspection.

Been looking at a number of different options.

First of all here are a couple of pictures so you'll see how much space (and angles) I have to work with.

Front view:

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From the back at the top:

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From the back looking down:

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Was thinking about making an L bracket that I can bolt to the seat (the 2.5" section between the holes for the seat belts. I'll use something like a carriage bolt with a rounded head on the drivers side of the seat.

Found a couple of brackets for the roll bar that will work:

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Or use a couple of these with the same L bracket

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Coleman also makes a parallel one that might be easier to bolt up to the L bracket on the roll bar side.

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Good way or is there a better way. All ideas appreciated!

Borderline (Bill) gave me a better idea.

Don't need a bracket, just run a bead along the roll bar with an upside down L bracket.

And bolt through bracket to the seat from the front.

Click to view attachment

I built one about 15 years ago for PCA club racing

I decided to punch a hole in the firewall and build a bracket that slid through the firewall to the seat. It was adjustable with a pin in the engine bay because we had 2 drivers and needed an adjustable seat.

my only thoughts about safety are:
if a wreck bad enough to deform the roll bar occurs... the seat could move forward or backwards with the bar and cause the belts to get tight or loose...

I know its not likely the roll bar would deflect, but you never know in a roll over situation.

by tying the seat brace to the firewall it was tied into the same place as the belt mounts... I figured if the firewall moved at least the seat would deflect with the belts instead of independant...

Good point about the roll bar deflecting and tightening or loosening the belts.

In my case the bar behind is there only for holding the seat belts, i.e., the bar goes between the outside hoop and the engine tunnel hump, i.e., the hump between the seats. We welded in steel bases on the hump to attach the belt bar.

In any event you got me wondering why SCCA requires such a brace. My only thought was that the brace was meant to keep the seat in it's upright position, but maybe there is another reason.

I'm not sure who adopted it first... probably SCCA, but there is a chance it could of been PCA.

I know why PCA requires it though
a gentleman driving a 911 in a club race about 15 years ago
he had a carbon fiber seat
he spun the 911 and wend into a concrete wall backwards at a high rate of speed

the seat broke in half from his body's G-forces going backwards at impact.

when the seat back failed and fell backwards it killed him instantly snapped his spine.

PCA very quickly began requiring seat back braces....
so that the seat could not collapse in that manner
I personally don't believe its necessary with an aluminum type seat (kirkey, ultrashield)

but rules are rules, even if they are blanket rules and don't apply to a particular person's situation.

so that is how the PCA began requiring it for club racing
I honestly don't know at what cronological point the scca began, and whether it was due to the PCA incident or an incident of their own.

brant

The aluminum Kirkey seats are pretty stellar. Hard to see how they would break; they might bend, but not much. And Kirkey seats sure have been involved in lots of accidents, especially in Sprint car racing. That was the reason I bought one originally.

The SCCA rule predates the PCA rule.
I was at the PCA race, at Lime Rock.
The story is a little different than Brant explained but pretty close.
Specifically, the seat didn't fail, it was the aftermarket sliding seat rails.

In any case, by SCCA rule, the seat must be able to withstand applied forces in side to side as well as fore-aft directions.
FIA seats don't require the back brace if installed per manufacturer's instructions.

Randal, how about a flat plate welded to the bar and a corresponding flat aluminum plate welded to the back of the seat.
The seat plate would lay on top of the fixed plate so 2 bolt holes could be drilled thru.
Advantage - no bolt heads inside the seat.

They are not as strong as you think. There is a relatively new SFI rating for seats (39.1 and 39.2). If you want to see a strong seat, check out one of those. Seats protect you the most in a crash, second only to harnesses to hold you in the seat.

To give you an idea, almost all NASCAR drivers have SFI 39.2 seats made from carbon fiber that Hendrick puts together. Only about $15,000. Used they are still north of $7,500.

Funny, but I woke up this morning thinking about how to minimize the bolt profile on the front of the seat and here you've already solved the problem. Nice work Chris.

I'm sure there are lots of opinions out there about the best way to secure a seat, but I prefer to bolt my (aluminum) seat to my seat back brace, which is welded to the cage in my case. The non-bolted variety should do the trick in a direct rearwared accident, but often hits are at oblique angles or the car is rotating in the accident. I'd think in those cases having having the seat secured to the seat back brace would be an added level of safety.

Scott