Widebody Track Car Build

[Dieselboy]

Seibon BM carbon hood arrived. I will be using Aerocach for latching and will ditch the gas struts for a standard hood prop. Weighed the stock hood at 45lbs and the carbon hood at 22lbs.

[Dieselboy]

Aerocatch latches installed. These were a pain in the ass.

[wdb]

I saw a ton of those when I played grid geek for BMWCCA at NJMP last month. Very popular option on the 3 Series racers.

[Dieselboy]

Originally Posted by mKilgore

Mark Aubele and his wife Michele. Great folks. Mark is here on the forums and there is a build thread of the 135i I think.

Small world, ended up buying a roll bar from Mark last night. Nice guy, lots of knowledge on this platform.

[Gary@simod.net]

make sure you put the factory hood safety catch back on..
Sometimes the aero aluminum pins snap and pop goes the hood!

[Dieselboy]

Originally Posted by Gary@simod.net

make sure you put the factory hood safety catch back on..
Sometimes the aero aluminum pins snap and pop goes the hood!

Yep, factory latch is installed. Put the roundel from the stock hood on. Ordered a carbon sunroof delete panel and I'll install the roll bar once I get that in.

[Suprgnat]

Originally Posted by Gary@simod.net

Sometimes the aero aluminum pins snap and pop goes the hood!

Originally Posted by Dieselboy

Yep, factory latch is installed.

FWIW, they do offer steel strike pins.

[Dieselboy]

My 6pt harnesses arrived. Anyone have any mounting tips?

My plan (using eyebolts and snap hook belt ends):
-Shoulder straps will wrap around the roll bar.
-The outside lap belts will utilize the OEM safety belt bolt hole.
-Not sure what to do with the inside lap belts. Drill and backing plate? Mount to the seat frame?
-Drill and use a backing plate for the sub belts.

[wdb]

Try looking in some competition org rule sets, or maybe the belt makers have tips. It's not a thing you want to get wrong.

[Dieselboy]

Originally Posted by wdb

Try looking in some competition org rule sets, or maybe the belt makers have tips. It's not a thing you want to get wrong.

Yea, all needs to be chassis mounted with belts in a certain angle range. Just curious how fellow 1ers did theirs.

[hoki06]

Originally Posted by wdb

Try looking in some competition org rule sets, or maybe the belt makers have tips. It's not a thing you want to get wrong.

This. Schroth has good installation guidelines as does the NASA CCR. I'm sure other orgs do also. You need to get the angles right or you'll paralyze yourself in a serious incident, especially the shoulders. Pay attention to the proper wrap methods around the roll bar and make sure all lap/sub belt mounting points are reinforced properly. OG Racing sells good pre-made mounting points that you can weld in place.

[mKilgore]

I scrolled back a page where you installed the seats, but could not tell how you mounted them to the frame. I see you used sparco seat adapters, but not sure what they are mounted to.

VAC motorsport has some great mounting options for lap belts and anti-sub belts if you used a seat mount similar to the one the offer. I use both and they were super easy to install.

[Dieselboy]

Originally Posted by hoki06

This. Schroth has good installation guidelines as does the NASA CCR. I'm sure other orgs do also. You need to get the angles right or you'll paralyze yourself in a serious incident, especially the shoulders. Pay attention to the proper wrap methods around the roll bar and make sure all lap/sub belt mounting points are reinforced properly. OG Racing sells good pre-made mounting points that you can weld in place.

Just read the SCHROTH install guide, very helpful.

Originally Posted by mKilgore

I scrolled back a page where you installed the seats, but could not tell how you mounted them to the frame. I see you used sparco seat adapters, but not sure what they are mounted to.

VAC motorsport has some great mounting options for lap belts and anti-sub belts if you used a seat mount similar to the one the offer. I use both and they were super easy to install.

I am using the Planted seat brackets. Everything I'm seeing leads me to beleive I'll need to drill into the floor for two eye bolts under the seat for the anti sub and one near the center console for the inside lap backed with reinforcement plates.

[Dieselboy]

These images are from the Racing Seat thread. He has the sub and side belts mounted to the seat frame (although the sub belt angle is way too large). If the seat frame is mounted to the chassis, and the belts are mounted to that, is that sufficient?

SCCA rules state:

The single anti-submarine strap of the 5 point system shall be attached to the floor structure and have a
metal to metal connection with the single release common to the seat belt and shoulder harness.
The double leg straps of the 6 point or 7 point system may be attached to the floor as above for the 5
point system or be attached to the seat belt so that the driver sits on them, passing them up between
his legs and attaching either to the single release common to the seat belt and shoulder harness or
attaching to the shoulder harness straps.


Each seat (lap) and shoulder belt of the harness (5, 6, or 7 points)shall have an individual mounting
point (i.e. 2 for seat belt and 2 for shoulder belt minimum). 6 or 7 point system anti-submarine straps
may share a mounting point with one or both seat (lap) belt(s). The minimum acceptable bolts used in
the mounting of all belts and harnesses is SAE Grade 5/Metric 8.8. Mounting hardware, including eye
bolts, as provided by the belt manufacturer, may also be used for mounting belts and harnesses.
Where possible, seat belt, shoulder harness, and anti-submarine strap(s) should be mounted to the roll
structure or frame of the car. Where this is not possible, large diameter mounting washers or equivalent
should be used to spread the load.

[hoki06]

Those will work and are better than other mounting points I've seen. If you've got a welder, your best bet would be to mount the seat in the driving position and then weld these things in the proper places to get the correct angles for both lap and sub belts.

https://www.ogracing.com/products/re...rness-mounting
https://www.ogracing.com/products/ey...ess-mounting-2

Picture from my old race car. If you look closely under the cage bar on the left you can see the other one welded to the body. Sub belt points are just below where the picture cuts off under the seat.

[wdb]

Originally Posted by Dieselboy

These images are from the Racing Seat thread. He has the sub and side belts mounted to the seat frame (although the sub belt angle is way too large). If the seat frame is mounted to the chassis, and the belts are mounted to that, is that sufficient?

I wouldn't think so. The belts are meant to hold you in the car, not hold you in the seat. OEM belts mount to the body. Sub, maybe. Side belts, I dunno.

I should fess up to my interest in the topic. I recently won a Caterham at auction and want to take it to PHA hillclimbs.

[Dieselboy]

Originally Posted by wdb

I wouldn't think so. The belts are meant to hold you in the car, not hold you in the seat. OEM belts mount to the body. Sub, maybe. Side belts, I dunno.

I should fess up to my interest in the topic. I recently won a Caterham at auction and want to take it to PHA hillclimbs.

But the OEM belt receptacle is mounted to the seat.

Maybe starting a new thread will get more replies. I would think mounting to the body would be the best practice, but if the seat frame is mounted to the chassis same as OEM, and if the belts are mounted to the frame it should be just as safe..

[DRLane]

Originally Posted by Dieselboy

But the OEM belt receptacle is mounted to the seat.

Maybe starting a new thread will get more replies. I would think mounting to the body would be the best practice, but if the seat frame is mounted to the chassis same as OEM, and if the belts are mounted to the frame it should be just as safe..

Brey Krause direct floor seat mounts have mounting points for both the lap and sub belts. They're arguably the gold standard for a commercial solution over the various MS or VAC style floor mounts.

"The R-926X seat mount line has been tested and certified by an independent lab to handle the types of forces required by the National Highway Traffic Safety Admin. DOT and SAE J385 Rev.MAR 95, Motor Vehicle Seat Belt Anchorages-Performance Requirements."

[Dieselboy]

So digging into the sub mounting today. There's really no ideal mounting position because of the speaker location and vent. The vertical distance from the seat sub hole to the floor is ~8". This means to achieve an angle of 20° the eye bolts should be ~3" rearward from the sub hole. Horizontal spacing between the eye bolts is recommended at 4"-6". I can just fit 4" as shown in the photo below.

Would love to see some photos of others who have mounted their sub belts directly to the floor. Load spreader plates should be here next week and I'll start drilling...

[Dieselboy]

Getting to the underside revealed that I'd have to drill into a support member to achieve the spacing I need. This is turning into a huge pain in the ass.

[spidertri]

Yeah, stuff like that is why the Brey-Krause seat mount setup is nice for the sub belts. Did you install that AutoPower roll bar yet? From other install threads, the main hoop reinforcement plate for that interferes with those lines as well.

[Dieselboy]

Originally Posted by spidertri

Yeah, stuff like that is why the Brey-Krause seat mount setup is nice for the sub belts. Did you install that AutoPower roll bar yet? From other install threads, the main hoop reinforcement plate for that interferes with those lines as well.

Not yet, was hoping to have my sunroof delete panel before putting the roll bar in, but I'll probably drill the holes now while I have the underbody apart.

The lines aren't the issue it's the support structure running parallel to those lines in the photo. I'll just get it as close as I can I guess. Best practice is to mount all belts to the chassis and I don't feel like dropping another $500+ on new seat mounts.

There's not much info out there on E8X/E9X belt mounts other than the seat cross bar setups. Closest photos for chassis belt mounts I could find is this from an E92 GT4, but the sub mounts look weird and too close together..



Based on the first photo, it looks like the sub straps are in the circled area here, which is odd, but apparently that's how the GT4 came from BMW..