Okay. I've got a racing seat. Next step is to get a harness. Will probably go with a six point. Shoulder straps will attach to a suitably safe and strong structure behind the seat (don't want to start a harness bar/roll bar/cage discussion.) It looks like I can attach anti-sub straps to a cross bar that is part of the seat base or maybe even the rear seat base mounting points.

The seat base has L-shaped brakets on either side. So the question is: Are these okay for the lap belts or do I need to drill holes in the floor/transmission tunnel? If so, can I use the stock left hand seatbelt mounting point and only drill one hole (tranny tunnel) for the right side mounting point?

 

Let's start with a SHORT discussion on properly installing a racing harness. The lap belts can be attached to the same mounting points the OEM 3-point harness uses. The sub belt can use the seat mounting plate if it's a racing seat. The shoulder belts are the biggest issue, since belt stretch and improper mounting angles can cause unnecessary injuries in an accident.

Do some research and you'll find the info you need...

 

Thanks. As mentioned, I've got that part figured out. Harness manufacturers cover that aspect pretty well.

I haven't had much luck with that when it comes to the lap belt attachment points, specifically in the 350Z. That's why I'm asking here.

If I can use the OEM 3pt attachment for the left side lap belt, that's great, no problem. On the right, it is either the mounting point on the seat bracket or a hole in the transmission tunnel. Would obviously like to use the mounting point on the seat if it is safe. The seat is used and very basic but it is FIA approved. It is bottom mounted on a Planted seat base. The Planted seat base uses the OEM seat mounting holes and the L-bracket on the side is made of the same thickness metal as the rest of the seat base and is integral to the base (not bolted on ).

 

I used the OEM belt monting hole for the outside belt anchors (same thread as OEM, anchors thread right in). On the tunnel side I drilled a hole in the floor/tunnel, used 2" x 3" Scroth plates on the under side of the vehicle designed specifically for this application of mounting anchor plates to the sheet metal floor. I did the same thing for the submarine belts, separate holes for each anchor with 2" x 3" plates under the. I read the Scroth directions, they are very clear on how and wear the belts should be mounted including angles for ALL of the belts.

No comment on using a harness without roll over protection ...

 

http://english.schroth.com/download/installinstru.pdf

 

DK, you try too hard, you just gotta let people be stupid...

 

Excellent info. Thanks.

Thanks, and just as well, that discussion has no end.

 

Thanks. I've looked over those many times and they are by far the best and clearest mounting instructions out there. Schroth also seems to have by far the best variety of mounting hardware options.

I do not have access to a lift so drilling into the tranny tunnel will have to be done by a shop. I can get the car up on jack stands myself but it would still be tight under there.

Bolting the right side lap belt to the floor seems like it would be stronger than the bracket on the seat base, but a lot more trouble.

 

If you are tall, you can use the outside stock 3 point belt mount, if you are short, you need to move the anchor forward. Then the sheet metal behind the seat is no where close to being strong enough for a shoulder mounting position.

 

I am 6'4" so the seat is all the way back.

 

I do not have a lift at the house either, it was no problem drilling the 3 holes/side (driver and passenger) for the inside lap belt mount or the 2 submarine anchors. I removed the seat, slipped the carpet out of the trim and drilled from the inside out once I checked and double checked where I wanted the holes. The harder part is trying to hold the plates under the car while trying to thread the anchor bolts in at the same time, by yourself.

 

That doesn't sound too bad and I can get some help for an extra pair of hands. My main concern from drilling from above is not hitting something important underneath and I'm assuming a few minutes scouting under the car should avoid that. Thanks again. I think I have a game plan at this point.

 

Tape and or jb weld is your friend here. I stick a dab of jb weld on the plate and let it harden for a sec. Same goes for bolt or nut when you get there. You could also use a bit of contact cement from a craft store.