Harness installation in 135i

[cjcjag]

I realize the 135i is so new in north america that no one may have done this yet, but does anyone have any thoughts about installing a racing harness in the 135i? Obviously there is no point re-inventing the wheel if someone has figured out how to do it properly.

[fourcylsgood]

First, install rollcage

[gargoyal]

It's not as crazy as it might sound. I was feeling the pull out of my seat just playing around on the test drive. If it does not look too ricey I was thinking about it

[fourcylsgood]

I believe these Schroth belts attach to the rear seatbelt mounting points
http://www.soloracer.com/schroth.html
http://www.soloracer.com/e36rallye4.html

easy to use/not use without installing a crossbar or half-cage to mount your FIA harness to, so you don't lose your back seat.

But! You don't want to be using a harness on the street without a cage in case you roll over and the roof crushes in on you. Lap belt lets you lean over out of the way, harness not so much.

[larryn]

I'm going to be at HMS Motorsports tomorrow, and I'll have Matt see if they have any quickfits that do fit. HMS is the sole US distributor of Schroth. They measured my e90 for those harnesses, a couple of years ago. I'll report back.

Btw, I'm @ HMS tomorrow from 10-2, if anybody plans on stopping by for the Performance Ground School.

[larryn]

Schroth does not have anything that would currently use the quickfit system on the e82 belt locks. They measured my front and rear belts. They differ slightly from the e36 rear, and e46 front. If they don't have them, it's extremely highly unlikely that anybody has a snap in solution. The belts are not the same mechanism as the e90/e92 in the back.

In order to have belts made and sold, they have to be created and crash tested. He's checking for me if they have that under development in Germany yet, and if not, he has my measurements to get the ball rolling. In the meanwhile, I'm going to use my Schroth Rally 4 belts for now, that bolt in.

[cjcjag]

Much appreciate the information already shared, although no immediate solution appears available (short of installing a full roll cage with the appropriate harness bar). I was not aware of Schroth harnesses. Hopefully they will come up with a sytem that will work in the 135i. Query: is Schroth an American or a European outfit (if European, they may already be working on one)?

[larryn]

They are German. HMS is the sole licensed importer, and they supply all belts to many racing groups, including nascar.

If you want a bolt in solution (as you would have to with a cage or bar anyway), they have the belts that I use, that you'd be able to use as well. I have the Rally 4 harnesses.

[BMWeber]

if you didn't plan on any car seats in the back you can remove the lower latch anchor points and replace them with eye bolts. we did this in my E46 M3 works great with quick disconnect latches.

[joe black]

Originally Posted by larryn

Schroth does not have anything that would currently use the quickfit system on the e82 belt locks. They measured my front and rear belts. They differ slightly from the e36 rear, and e46 front. If they don't have them, it's extremely highly unlikely that anybody has a snap in solution. The belts are not the same mechanism as the e90/e92 in the back.

In order to have belts made and sold, they have to be created and crash tested. He's checking for me if they have that under development in Germany yet, and if not, he has my measurements to get the ball rolling. In the meanwhile, I'm going to use my Schroth Rally 4 belts for now, that bolt in.

Larryn, Are you saying that Schroth Quick fits for a E46 won't fit in a 135 because the seatbelt couplings are incompatible?

[larryn]

That's exactly what I'm saying. The buckle catches are different.

[WhiteOut]

Has anybody thought of using the hooks provided in the back that are intended for baby seats? Seem like they be perfect anchors for a harness.

[adc]

Originally Posted by WhiteOut

Has anybody thought of using the hooks provided in the back that are intended for baby seats? Seem like they be perfect anchors for a harness.

I don't think they have the same load rating - think of the weight difference between a child (even in a heavy childseat) and a 250 lbs adult. These hooks are only meant to be used with LATCH-equipped seats, which in my experience are only used for toddler seats (up to 60 lbs child, plus 10-15 lbs weight of the seat).

In my 335 I'll use the poor man's harness for her first US track day: CG lock on the buckle, belt locked via the seat-move-trick and lateral seat bolsters to their tightest position. Not as good as a harness obviously, but a world away from just regular seatbelt.

[emongoose]

Originally Posted by adc

I don't think they have the same load rating - think of the weight difference between a child (even in a heavy childseat) and a 250 lbs adult. These hooks are only meant to be used with LATCH-equipped seats, which in my experience are only used for toddler seats (up to 60 lbs child, plus 10-15 lbs weight of the seat).

In my 335 I'll use the poor man's harness for her first US track day: CG lock on the buckle, belt locked via the seat-move-trick and lateral seat bolsters to their tightest position. Not as good as a harness obviously, but a world away from just regular seatbelt.

Yes... but the design would be to restrain 75lbs of child and childseat in the event of a crash... which the laws of physics says can create substantial mass at impact. Not really knowing what the engineers used (weight, impact speed, etc) to determine the "strength" of the anchors, a layman’s guess would put that much higher than the force created to keep a 250lb autocross driver glued to his seat. Using this same mounting location to restrain a driver for protection from impact is an entirely different matter. But if autocross drivers are looking for ways to keep their butt and upper body firmly planted in the seat during autocross maneuvers, then the baby seat anchors have good possibility.

I'm not an engineer, or a safety belt authority... this is merely conjecture.

[Evolution Racewerks]

If you guys are planning to use the harness for racing, I don't think you'll pass inspection using the rear seat belt buckle. Also, the angle of the rear straps will be too sharp and it can be dangerous in a crash. If I recall, proper strap mounting is no more than 25 degrees. Reason for this is upon impact, if the angle is too sharp, the belt will leverage harder pushing you into the seat and that can possible break your back. Probably won't even pass inspection if you get a strict inspector.

Since in our class, we need to retain the rear seats, I first looked at that option. However, the angle was too much and I knew it would be a problem. Instead, I built a harness bar that goes over the rear seat, giving me the proper harness angle. It mounts behind the seat in the trunk. This lets me retain the rear seats and keep them in the upright position. That was needed for our methanol injection tank which is in the trunk and if I had the rear seats down, I would need a bulkhead, again to pass inspection. With the rear seats in the upright position, that becomes the bulkhead I needed.

I will take some pictures when I get a chance. I can duplicate it without a problem so if enough of you guys are interested, I can build more.

[Evolution Racewerks]

Safety equipment should be regarded as the most important thing on the car that MUST be done right. I only have 1 life and I wouldn't risk it. :wink: If you don't mount the harnesses correctly, you can cause more injury to yourself then just using regular seat belts.

Originally Posted by emongoose

Yes... but the design would be to restrain 75lbs of child and childseat in the event of a crash... which the laws of physics says can create substantial mass at impact. Not really knowing what the engineers used (weight, impact speed, etc) to determine the "strength" of the anchors, a layman’s guess would put that much higher than the force created to keep a 250lb autocross driver glued to his seat. Using this same mounting location to restrain a driver for protection from impact is an entirely different matter. But if autocross drivers are looking for ways to keep their butt and upper body firmly planted in the seat during autocross maneuvers, then the baby seat anchors have good possibility.

I'm not an engineer, or a safety belt authority... this is merely conjecture.

[SV Concepts II]

Originally Posted by Evolution Racewerks

If you guys are planning to use the harness for racing, I don't think you'll pass inspection using the rear seat belt buckle. Also, the angle of the rear straps will be too sharp and it can be dangerous in a crash. If I recall, proper strap mounting is no more than 25 degrees. Reason for this is upon impact, if the angle is too sharp, the belt will leverage harder pushing you into the seat and that can possible break your back. Probably won't even pass inspection if you get a strict inspector.

Took the words right out of my mouth.

Your harness bar is mounted behind the rear seats so technically it's not in the cabin correct? is it bolted or welded? I've heard horror stories regarding driver injuries involving airborne harness bars. Because of this I've always been weary of harness bars. Was this an issue you came across and if so what did you do to prevent it?

[larryn]

I initially used the ISOFix points, and was told by the NA Head of Schroth (know him), that those anchor points are not to be used in that manner.

I then bolted them in to the rear belt anchor points.

Been tech inspected numerous times, and passed without a problem using this method. I made a DIY on how I installed them, if you have not seen it yet.

[white911]

this just came up recently as someone on another forum was asking whether PCA allowed four-point belts. Schroth has a four-point harnesses specifically designed for a specific car/seat combination. For our track events we have specific mounting requirements for harnesses and generic four point combinations are not allowed. Seats must have specific routing holes for shoulder harnesses and sub-straps. Finally since all belts stretch in a crash, it is important for belts to be as short as possible.

Personally, when my fiance started driving, we had a friend crash at the Glen when a fuel manifold failed coming through the toe and she ended rolled onto the side of her car. She was wearing full 6-point harness in a cage equipped car and smacked her head on the armco. After that I installed the full cage, semi-containment seat (Sparco Circuit Pro), and new 6-point harnesses. Now I won't drive without the Hahns.

When starting out it is not necessary to go berserk and put everything in the car. You may end up liking it so much that you decide to go with a dedicated track car. I can say that the 135 in its stock condition is easy to drive fairly quickly on the track without resorting to cage and harnesses. The steering only requires a light touch and there is virtually no kick-back and the sport seats are very supportive. One step beyond this would be to install that thing that locks the shoulder harness, or a combination of that and a three inch lap belt; but, I really don't think that is necessary until you get rid of the run flats.

I suggest checking with your main event organizers to insure that you remain in compliance with rules.

[emongoose]

Originally Posted by Evolution Racewerks

... "Instead, I built a harness bar that goes over the rear seat, giving me the proper harness angle. It mounts behind the seat in the trunk."...

"I will take some pictures when I get a chance. I can duplicate it without a problem so if enough of you guys are interested, I can build more."

I would be interested in what you've done with this. I used a harness bar on my corvettes, which worked really well. Only issue I can think of is finding shoulder straps long enough to reach to a bar mounted just behind the seats. Cool idea though... on non-race days the bar and belts wouldn't even be visable.

[jah29]

Evolution Racewerks-

Please post pictures of your rear harness bar. I'm not quite sure I understand exactly where the bar is located (especially vertical orientation) in the trunk, but it sounds exactly like what I'm looking for.

thanks.

justin

[emongoose]

Originally Posted by Evolution Racewerks

..... Instead, I built a harness bar that goes over the rear seat, giving me the proper harness angle. It mounts behind the seat in the trunk. This lets me retain the rear seats and keep them in the upright position. ....

I will take some pictures when I get a chance. I can duplicate it without a problem so if enough of you guys are interested, I can build more.

Still hoping to get more detail and see some photos of this setup! :smile: