Dwane

See below

mglobe

I'll add on more thought on that. A number of years ago, I backed into a wall going bout 70mph. I had a composite seat mounted on Sparco sliders, and no seat brace. The sliders held up, but the seat was deformed by the impact. You could see when you looked at it that it was out of "square".

The components of the driver restraint system (belts, HANS, seat,...) are designed to have some give in them. It's all about spreading the deceleration out over a slightly longer period of time so that the driver experiences lower G-forces. Had I had a seat brace behind my seat, there would have been no "give" in the seat. My seat wouldn't have deformed, but I wonder about how my back would have fared.

Matt Romanowski

I don't believe the system is supposed to have any give in it based on my understanding of safety seminars given by Dr. Melvin, Dr. Trammel, and others at the Stand 21 Racing Goes Safer events. I could be wrong though.

38D

I do not know which incidents Walt used, but I have personally seen stock seat mounts fail twice. The first time was on a 914 that I owned. I crashed the car back in ~2002, and one of the rear seat mounts pulled out. I was lucky it was not a harder hit.

The second one was a crash a friend had in a 964. The seat mounts on one side partially failed, and he ended up breaking a couple of ribs. The theory was that he hit the door bar on the cage.

While I realize this may be an inconvenience, Walt is not doing this to be a pain. He's just trying to help keep us as safe as possible. I remember similar debates a few years ago when a HANS was required, or we started requiring cages (that was my suggested rule btw).

mglobe

Think about it. No give makes no sense. Surviving an impact is about not hitting stuff with your body, and about spreading the change in velocity out over time. That's why modern cars have crumple zones in them. The crumple zone absorbs some of the g-forces. If harnesses and seat belts didn't stretch at all, they would injure the driver. Same goes for a seat. The seats and belts need to keep you from moving far enough to come in contact with the rest of the car, but they also need to absorb some of the deceleration so that your body isn't exposed to horrific g-forces.

Just watch the Elliot Sadler impact at Pocono, and imagine what he would have experienced if his harnesses didn't stretch some.

Sean F

If this truly is a big concern then the stock seat rails and mounting hardware should be addressed, not just sliders

KaiB

At what point then do we demand that seat mounts are reinforced? How and by whom and in accordance with which engineering?

This opens doors for all kinds of failure. The stock (tub) seat mounts certainly were engineered by Porsche and homogolated into their race cars of whichever era they raced. (i.e. if the factory tub mounts were good enough for the 964RSR, they should be good enough for me)

To expand issues further, we are now talking about modifying seat (side) mounts and sliders to make them fit. Who on earth will engineer that, who will design the modifications and then pass them on through to the manufacturer to insure that the original integrity of the mounts and sliders are retained?

To be specific, what's wrong with MY current setup: 964 in good shape, Recaro double locking sliders, and proper side mounts/seat. Why on earth would I want to mess with this before I spend the same money to have my wheels Zygloed, or pay a reputable shop to nut and bolt the entire car to double check my work, or even flush my dang brakes yet again.

At what point do we draw the line...I'll wager that a far greater number of theoretical safety related failures in other parts of our cars (wheels, suspensions, brakes, oil lines, etc) will occur on track this year than seat mount issues.

flatsics

I have had fix/repair numerous stock Porsche seat mounts
Broke my 964 seat mount at Watkins Glen two years ago.

I have repaired seat mounts in bunch of stock Porsches.
944's,911's,996's


I have repaired the tub on my old 79 911 too many times to count from fatigue.

Ripped out front sway bar mount
Front control arm mounting point
Rear spring plate mounts
Replaced rear sway bar mounts

Racing is hard on your Porsche and stuff fails over time.

paradisenb

Safety? Really? I'm all in! Can we remove our passenger seats in our Stock Class cars? Now that would be a safety improvement.

I am having Boxster sliders installed now. It is a challenge in my old car. The sliders are taller and the pins require additional clearance. The seat sits higher and I don't "have a square to spare". I want welded in supports, not just through-bolt and backer plate mountings. Well, this raises them a little bit higher still.

One very nice thing about the Boxster sliders is their travel. With a halo seat and short legs, the extra travel make ingress and egress MUCH easier. That is a safety issues worth regulating.

flatsics

Example of some fabricated seat mounts in 964's

http://www.izzyscustomcages.com/

paradisenb

^^^ This what we are trying to fit in my SC. This system moves the seat way to high. Still messing with it though. Hoping to find a similar setup that allows head clearance.

jurnes

I talked to Recaro rep "Jeff". He stated that the seat slider shown here is only available as a complete seat/slider unit RECARO P1300. The retail price is around $10,000.00

Astroman

So I just got back from a test fit after my shop installed the Porsche sliders in my '87 911 in anticipation of the 2015 rule. And I'm happy to report that I am very pleased with the results.

My tech (a creative and capable fabricator) was actually able to LOWER the position of my seat with the new sliders while using the stock floor mounts (lowered and reinforced) and my existing (modified) BK side mounts.

None of the installation modifications that JWE has developed (rail extensions, custom side mounts) were necessary for my car/seat (Sparco Pro ADV).

And the Porsche sliders appear to be far superior to the Recaro/Sparco/Sabelt sliders I was using. The action is very smooth and mechanical with two pins engaging per side. I'm impressed.

I'll try to post some pictures when I get the car back next week.

DaveConn

The first pic Doug posted above is my car. At the time, one of my forward, factory mounts was cracked, so combined with my need for a little more headroom, this is the configuration Scott came up with. Works fantastic, and definitely a lot beefier than stock, but as you can see, it's a bit of a mess to fabricate/install. We were already into stripping the interior and fabricating the cage, so no biggie at the time...