tall people cage questions (harness bar placement) Options

[smdubovsky]

Hi guys, been a while since I've posted. Im reworking the cage in the /6 to fit me better. When I bought it, it had a "short people" main hoop design;) The harness bar went straight across and the triangulation went the the upper corner. It limited the seat from moving back another 8+". The harness bar was also *WAY* too low. I'm 6'2" w/ long legs and need all the room I can get.

Here is what it looks like now (red = the bars I cut out, green = ones Im going to install)


Here you can sorta see how low the old bar was - below the door tops.


Ok, now here is my big question: Instead of the usual zig back behind the driver (tight against firewall), zig forward across the center firewall 'hump' (tight to firewall), and head straight across to the passenger side (w/ a gap to the firewall) - I want to do a zig back (tight to firewall), go THROUGH the hump, tight against passenger side firewall, and zig forward to the main hoop. This will be just above the existing fan cutout the POs did, and above the top of the fan housing (but not really as much as the pic shows). When the seat tilts back a little more, the shoulder 'wing' gets pretty darn close to the hump so there really isn't space to route the bar completely inside the cabin. I can't really bolt eyebolts to the firewall and forego the harness bar either - they'd get too close to the seat w/ the mounting clips and adjusters (which would then actually be sitting on my shoulders.)

Heres s shot of where I want to cut though the 'hump' to put the harness bar.


I'd leave ~1/8" between the firewall and bar behind the seats so I could still wrap the harnesses around.

Thoughts? Has anyone done this? I'm not racing this car so I have *NO* class rules to follow, but thoughts about legality if I ever get rich and change my mind would be interesting;) I think if I did a larger cover w/ ears and sealed it well, it wouldn't really count as another point.

[Krieger]

Hey, I'm working through a cage set up for my track car and was considering this as one option. I appreciate the picture with the fan in the background. I wasn't sure if this would be in the way or not. It looks good. I'm 6'4 and will be dropping the floor down about 2" for me to fit better. My only thought. Do those bends around the hump add more strength than the long straight piece that goes through the hump?

[Richard Casto]

Stephen,

I had not really thought about running the bar through the hump. I have yet to buy my seats, but does it really save you that much room vs. the zig around the hump?

I am 6'5" and I am "trying" to find a way to make this work with a cage low enough that the top can go on and without lowering the floor. I "think" I can do it, but much of this relies upon something like a Kirkey/Ultrashield aluminum seat bolted directly to the floor an the removal of the cross brace that the factory seat height adjuster bolts onto. Time will tell if this works or not.

[sww914]

I'm worried that the harness bar running through the hump will make an already difficult to replace alternator impossible to replace in the car. Have you considered using smaller diameter tubing for the harness bar? I don't know what the organization's rules say but I think that a slightly smaller bar with no bends in it will be stronger than a larger bar with bends. My old roll bar had a bolt in harness bar that mounts to the stock shoulder belt lugs. My cage has no harness bar at all, just 3" X 4" plates bolted to the firewall with the eyelets bolted through, nobody has questioned it.

[SirAndy]

i'm 6,2" and here's what i got:

(IMG:style_emoticons/default/shades.gif) Andy

PS: my cage was build by Tony from TC Design and he did a great job!
http://www.tcdesignfab.com/porscheprojects.html

[smdubovsky]

Thanks guys!!!

Andy Brain,
A straight bar is stronger than a bent one. Since you brought it up: I MIGHT cut into the floor to lower the seat at the very back edge *IF* I decide to install sliders (pretty much just about 1/2" just to accomodate the slifder height.). I leaned the seat back a little to gain the needed headroom. I wouldn't feel comfortable moving the floor down a full 2". That easily makes your ass the lowest point of the car - it would drag on everything.

Richard,
I looks like I might be able to keep the center crossbrace - the front lip of the seat clears it w/ the amt of tilt I need. I might angle the top edge of it to match the seat mount angle. I'll only move it fwd if it gets in the way of the sliders or something (again, *IF* I choose to use them)

Steve,
You mean the alternator harness under the shroud? I hate that freakin' job on a 911 as it and you don't have to work down a dark hole;) I would just drop the motor since its a very rare occurance. W/ carbs, its an easy job to drop. Id rather do that than sacrifice useability the other 99% of the time.

Again, I don't think I can use eyebolts bolted to the firewall. They take up MORE space than the bar (1" eye + 2" clip end + 1" 3-bar adjuster = 4" vs 1/8" gap + 1.5"bar + 1" adjuster = 2-5/8")

Sir Andy,
Im familiar w/ the TC design. Brad did the PPI on my car back in san diego said it looked like a very good copy of the TC except for the braces. The owner and codriver were both very short, so they didn't do the fancy rear braces. The reason I don't think I can do the arched brace is the shoulder 'wing' on the seat. W/ the seat snugged up against the center tunnel, the headrest almost against the rear glass, the 'wing' almost hits center hump. Definitely would have to move the seat fwd to clear a 1.5" tube in the correct point. Due to the back curvature in most composite seats and the lean, there is still a good 3" or so behind the shoulder slots to the firewall. So, the bar will fit behind the seat ok, but not bewteen it and the center hump - which is why I postulated running it though the firewall.

There is one thing we thought of later: Use flat bottom U-bolts instead of eyebolts attached to the firewall. I could wrap the harness around them like a cage and gets loads of clearance since there is no clip in end to use. I'll post a pic. I could reinforce the firewall w/ a small beam on the motor side - but I would still prefer to bolt into the cage.

[smdubovsky]

pic of the flat bottom U-bolt idea instead of an eyebolt.

[sww914]

That's a good idea! Nice drawing.

[smdubovsky]

To update this thread: I bit the bullet and went through the firewall. It has saved alot of space vs a typical 'zig' like andys. Here are the pics of it going in. Its hard to see in the last pic, but I tacked a piece of 3/32 tig rod half way around the back of the bar nearest the bend. This presses the firewall back JUST far enough to get harnesses around there comfortably (and prevent any rattling). You can kinda see the top of it near the marker outlines I drew on the firewall.

Made the majority of the slot w/ a large cutoff wheel. Did the round ends w/ a plasma.


Welding her back together


My flat black is still shinier than what the PO used. I plan to use foil tape to seal the gap.

[smdubovsky]

And here is the seat mounting. Since this will be a street/DE car I wanted to use sliders. Being 6'2" thats not an easy thing to do. So I sunk the rails into the floor by ~3/4". I used 2.5" rectangular tubing, sliced in half, and created U tracks. I also welded a tube across the bottom of them for the sub harness.

BTW, I welded a shorter piece of sq tubing under the car that slopes back up to the firewall. So the bottom of the car has a very shallow 'V' instead of an abrupt lip at the rear of the sliders. I was worried if I spun backwards over a curb it would be better to have a shallow ramp than a sharp edge though would rip the pan off the car. (I don't have a pic of those at the moment)

BTW2, its just (bad) flash rust on the front part of the pan. Its all cleaned up, zinc phosphate etched, and rattle can painted now.



I cut the 'hump' over the tunnel flush w/ the edge to mount them as close to the center as possible.



The seat mount very close to the tunnel.




W/ the seat all the way back there is ~1" from the seat 'ear' to the hump. A 'ziged' harness bar would have never fit - esp one w/ ANY gap between the bar and the hump.. There is <1/4" from the seat back to the lower part of the firewall. The upper part of the seat ALMOST touches the harness bar and is ~1/2" from the upper part of the firewall just under the rear window. It can't go back any further;)





BTW, The seat bottom has ~1/4" gap from it to the floorpan. The sparco sidemount mounts themselves limit that. My bum is ~3/4" off the floorpan w/o a cushion. It allows me to pass the 'broomstick test' w/ a helmet on by ~1/2".

In retrospect, the only downside to this is that I sit ever so slightly under the main hoop. Proper assymetric FIA padding JUST pushes my helmet forward slightly . Im not about to cut the main hoop just to angle it back another 1/2" though.

[smdubovsky]

Correction, I do have a pic of the underside.

[URY914]

Very nice work.

[Richard Casto]

Stephen,

Looks good. With you being 6'2" and me being 6'5" and you only had 1/2" clearance, getting my seat low enough is my #1 worry area on my car. I am going to be ordering Kirkey seats soon and doing some test fits.

So you happen to know what degree angle your Sparco seats are?

Richard

[Krieger]

Hey Stephan good work. I am slowly getting into mine now, with the floor cut in a u shape. Are you using the sparco sliders? I am. I have been playing around with mine and the thought to mount my sliders on the side of the seat between the bracket and the seat. Anyone ever done that? Or are their any sliders out there for specifically for that?

[J P Stein]

Got the seat an inch & change lower....coulda got more but I couldn't see over the windshield. Bolted a aluminum plate to the bottom of a Kirkey seat & the stock seat runners to that.

[smdubovsky]

I actually went out for a short drive today. It hasn't moved in QUITE a while so Im a very happy camper. Still needs lots of other work though. Baby steps.

Richard,
I do not know the angle of the sparco seat. If I can find my digital camber gauge I'll try to measure. The seat essentially touches at two points on the firewall, so the angle is sorta matched to that. It wont go any farther back w/o relocating the whole firewall. To go down, you're going to have to cut into the floor. The sparco mounts are 'L' shaped and wrap under the bottom of the seat. If you flipped them or just made your own, you could get another 1/4-1/2" or so. More will require tucking the back edge of the seat into the floor. Where does your height come from? legs or torso? I have a true 36" inseam (measured w/ a book wedged in your crotch to floor w/o shoes - hey its a cycling measurement;)

Andy,
Yes, Im using the sparco sliders. Never thought about mounting them to the side. There would be no way to actuate them w/ one lever though. I doubt they've been tested in that configuration either.

JP,
I don't think any of us have trouble seeing over the dash;) I suspect for Richard,Andy, and myself in most cars its the opposite - seeing under the upper lip of the windshield (and that darn rear view mirror that ALWAYS mounted too low blocking vision for right hand turns;)

[Krieger]

I always have a problem with the rear view mirrors in cars. I am just under 6' 4" and mostly torso. If the sliders were on the side you could have 2 short handles, but like you said they probably have never been used that way.

[J P Stein]

My windshield is a bit different. For autocross I wanted to see the ground 20 feet in front of the car.

[smdubovsky]

JP,
Hahahaha. Yeah, thats a different animal;)

Your bar extensions do give me an idea for other cars. It would be relatively easy to put mounting bosses in the main hoop so you could bolt a short height attachment on at the track. It could be as simple as another 1.5" bar laid on top of the main one (and bolted to it) to pass the broomstick test. Would have to run @ the track w/o the roof on, but its a simpler option for those w/ multi purpose cars.

[J P Stein]

I doubt my roll hoop would pass SCCA tech. Maybe if it was grandfathered in....but now days they are very specific about the main hoop's construction.