moespeeds

I'm a tall dude and the Hardbar that the car came with prevents me from getting the seat far enough back. I know Hardbar sells an extension but I'd rather just fab my own bar and sell the Hardbar that's in the car now. Here's a drawing of what I want to do, my question is will it pass a tech inspection?



I'll use a thick walled 2" steel tube, TIG welded to 1/4" x 2" extension plates on either end. The plates will be angled to match the A pillar, and then I'll weld a piece of angle to the plate, tight against the A pillar to prevent the bar from rotating up or down under load. Any issues with doing it this way?

My other issue is the existing lap belt mounts. It's a big bracket bolted behind the seat that's also in the way. What I'd like to do on the driver's right side is drill a hole in the tunnel and use an approved eyelet, backed up with a fender washer. On driver's side left I only have the frame to work with, so I'd like to fab a 3/16" steel plate bracket similar to the picture below, and bolt that to the stock seat belt mount. The anti-sub belts will clip to approved eyelets bolted through the seat rails.



Would a tech inspector have issues with any of this?

trackboss

Your tubing size and plate is way overkill for what you are doing. Way heavy and not necessary. Your entire harness bar is far stronger than what you are attaching it to and really unecessary.
IMO, your proposed idea seems good and well designed. If any tech inspector doesn't pass it they need to find another outlet for making themselves feel better than the next guy. There are times where you will run into tech inspectors and "instructors" who think they know it all. I've always said that unless these are paid, experienced, people you are just getting volunteers that are only giving thier opinion. Especially with so called driving "instructors".

moespeeds

Ok thanks, the materials spec'd I have laying in my scrap bin. After ripping off the trim panels and headliner I want to add a roll bar. That hoop looks way flimsy! Just an FYI, I pulled all carpeting, sun visors, CD changer, stock belts, and all plastic trim except the dash and center section. Total weight removed was 70 lbs.

Bill Dearborn

Nothing wrong with adding a roll bar but the roof halo is very strong and the roll bar just becomes a harness mount. There have been pictures of flipped C5s and C6s and that halo has really held up well. The weak points are the A Pillars. If you are going to a roll bar go the distance and put in a cage. Otherwise just do the harness bar.

Your idea of putting a lap belt mount on the tunnel is an excellent one. As for the harness bar/roll bar/cage get the diameter down to 1.75 or 1.5 inches. It makes it easier when you want to attach things to the bar. Nothing is sized for a two inch bar from seat braces to most camera and fire extinguisher mounts. I had a two inch roll bar and had to cut out everything to make them fit.

As for the outside lap belt mount take a look at how the outside mount of the BK lap/sub belt mounts between the frame and the stock C5 lap belt retractor. Another way of mounting the lap belts is to mount them to the seat bars. I did that with mine. The belts are mounted to the ends of the Hardbar rails with Chrysler OEM seat belt shoulder bolts that I got from a restoration site on the internet. I think they were for a 71 Dodge Dart or something. I had to drill the holes in the rails and the lap belt end links out a little but the shoulder bolts provide just enough gap between the seat bar and the bolt head so the lap belt swivels just enough.

This picture shows the belt mounted to the rail before I put the Seat Belt Shoulder Bolt in:


The picture also shows a 17 inch seat set on the Hardbar rails. The lowest it can go in a C5 is to the top of the rails since there is no more room to spread them further apart.

6-20-12 Just a quick update to this post. The picture shows my lap belt fastened the wrong way. To be correct the end has to be folded back through the buckle one more time. When installing your belts be sure to follow the manufacturers recommendation on how to wrap them.

Bill

trackboss

Bill, I have a similar seat (kirkey road race deluxe) and was able to mount it lower. What I did was set up the rails as you have with one difference. I did not use the rear uprights. I bolted the rear of the seat directly to the rails and in the front what I did to line things up was to use a 1/4" spacer between the upright and the seat. I played around with many positions and found that the original holes placed the seat uncomfortably low(legs were too straight towards the pedals). What I did was drill an additional set of holes in the rails just a bit higher an it all worked out well. In the photo below you can see what I did. The spacers are not visible, but it should help explain what I did.

Bill Dearborn

I tried to do something like that but the 17 inch seat was too wide to fit between the rail with the stock interior trim and seat belt reel in place. The other thing is the bolt holes going to the floor mounts would have had to been elongated a little more. Where did you find room to mount the sub belt? Even with mine riding on top of the rail there is little room to mount it.

Bill

trackboss

That's odd. Mine's a 17" as well. It is tight, but fits.
I use the teamtech jet pilot harness system that eliminate the need for a sub belt. I have said it before, it is the best harness available. Easy to install, comfortable (your ***** will thank you), and about as good as it gets in quality and safety. It is worth every penny. FWIW, I mount the lowers using clips and eyelets mounted to the rails. I only snap them in (takes about a minute) when I need them the rest of the time I completely remove them and tuck them behind the seat. I use my factory belts on the street. There are no issues using the factory belts with my seat and body type. Although, passing the entire ratchet mechanism through the side hole on the side is very challenging. Some seats may not allow that and in that case it may not be safe.

moespeeds

Well here is what I came up with:

Completed harness bar, 2" OD, it's what I had laying around:



This is the bracket that the top of my Ultrashield seat bolts to:



Whole thing installed:



Here's a universal camera mount I came up with. Simple and easy. The strap is just for safety so the whole thing doesn't become a missile in a crash, the camera is bolted to the mount.

trackboss

Looks good. If it were me I'd prefer to weld a threaded bung in the hoop to allow for an attachment to triangulate the mount and eliminate rotation possiblity. I'm not sure if that would interfere with the plastic trim. Of course, if you are not re-installing it then it is a non-issue.

moespeeds

My original plan was to weld a bung on the hoop but I was concerned about heat transfer into the outer panels, so I came up with the anti rotation bracket. It does the job without having to weld to the frame of the car.

Bill32

If you came thru my tech line, I'd have my guys pass it.

But then, there are no guidelines in SCCA for harness bars in PDX (HPDE), but there are for rollbars, go figure.

On the track, as an instructor, I'd feel comfortable with it.

BTW, the 2 inch is large, yea, but whatever was laying around your shop....
If you compared it to rollbar specs - 3/16th min. mounting plates and 1 1/2 rould tubing with .120 wall or 1 3/4 tubing with .095 wall

trackboss

FWIW, coleman does have 2" I.D. aluminum accessory clamps with threaded holes to attach stuff to.
http://www.colemanracing.com/Chassis...nsion-C14.aspx
You can also buy split shaft collars from any of the industrial suppliers in a variety of materials. Typically found in power transmission equipment.