^+1, rip it out. Youll be kicking yourself in a few months when you realize this was prime time to do it.

 

I'm not going to remove it at this point and here is my thinking on this:

1. It isn't 'dead' weight if it is a structural component which it clearly appears to be. So function is lost if I remove it. As dkmura mentioned, the roll bar would probably not replace that loss of strength/rigidity.

2. My current priority is safety. If the box is structural I'd rather have the strength.

3. It is not going to impact placement of the main hoop. The installer can get the hoop as far back as it is reasonably safe to go without me removing the box.

4. The amount of weight lost is not going to impact my track times in any significant way even if I try my hand at TT.

5. It will not be that much harder to remove it after the bar goes in than before so it won't be a big deal if I decide it has to go.

That's my logic. It might be flawed but it makes sense to me now. Thanks for all the advice and helping get all this sorted out. I'm going to order a G-Force camlock 6 point with mounting hardware soon. I'm still debating about using the seat mount for the right hand lap belt verses transmission tunnel but will likely go with backing plates and trans tunnel.

 

#5 all the way. Once you've stripped the interior, there's not that much of a problem to remove the speaker box if you decide to later on. N80's logic is sound.

 

I ordered the G-Force 6 point cam lock harness last week. It will get here today.

I bought Schroth backing plates for the two sub straps and the right side lap belt mount point. I also bought the Schroth bendable attachment points just in case alignment is an issue. With my current race seat it looks like I can use the floor for the right side lap belt attachment point. If I got a wider seat it will have to be the transmission tunnel.

 

Agreed that you prob wouldn't notice the difference in lap time if ur an average driver... but just FYI the box is not a structural member. Was an engineer at Nissan 3 years ago.... mine has been removed.

 

My goal is to someday be an average driver.

 

Mine is out. Definitely a little easier to do before a roll bar/cage....

 

I'm not an engineer, but I just don't see how that piece could _not_ be structural (at least a little) even if it wasn't intended to be. It is welded into the floor and high up the chassis sides and goes from one side to the other and does not seem to flex.

I've got a few weeks before I take it to get the roll bar in so I'll continue to think about it.

 

A few more questions:

Is the trans tunnel a single layer of sheet metal or is it two layer like the floor?

I have a backing plate for it but now I'm wondering if it is only a single layer of sheet metal would the mount on the Planted seat bracket be a stronger mounting point?

Also, what do you guys do about the foot well? With the carpet out there is a piece of styrofoam on the left of the foot well with some other sort of padding under that. Wondering if some of that is heat shielding since I think the cats are just underneath there. I'm thinking that I may put the carpet back in.

Edit: Here is a tip for anyone going through this same process. The short Schroth eyebolt fits perfectly in the left side seat belt mount and makes a perfect, easy connection for a snap in.

 

Nobody knows if the trans tunnel is two layer or not? I've got it up on stands now. Will probably drill next week so I'll post back what I find. From underneath the car it seems like there is plenty of clearance in the trans tunnel to get a bolt and backing plate in there.

I think I will drill a tiny pilot hole from inside the car. Probe it with a wire to see if it is two layer or not and make sure I don't feel any kind of wiring or lines under there if it is two layer. There are no visible lines or anything looking into the trans tunnel from under the car.

Getting excited about getting this done. Will order head and neck restraint next week.

 

Got all my holes drilled. Trans tunnel is one layer of sheet metal. It is fairly sturdy and seems thicker than the sheet metal in the floor. Drilled the hole and mounted a Schroth 38mm eye bolt with a Schroth backing plate. The 38mm eye bolt is longer than it needs to be and the shorter one would work just fine in that location.

The holes for the sub belts is a bit more tricky and the floor is very irregular where those mounting points need to go. The sheet metal there is fairly thin, one layer and there are channels, groves and humps as well as a beam-like structure under the car in that area that you have to work around. My mounting points are wider apart than I'd like them but the belt angles will still be correct.

 

Sorry to bump an oldish thread but I'd love to see some pics of 5/6 point mounting points if anyone would like to share. On the Evo X I've see people modify the Planted seat bracket to accept sub belt/s, is this not a prudent idea?

thanks,
JJ

 

From a safety perspective independent mounting points for the belts is better (more redundancy). But if the belt and mounting angles conform to your ruleset then I would say it is technically ok.

Also depends if you mean using the existing forward portion of the planted bracket or welding in an additional support to it. When you actually have it in front of you, you realize it is difficult to do per the rules without modification, and not really worth it imo, better to get a fabricator to whip up some independent mounting points.

 

I think independant mounting holes in the floor is easier and sounds like it is safer too. Was for me anyway.

 

Of course, there's no real way to know if one method or another is "safer" until a shunt actually happens. But most harness instructions indicate the shorter the belt length, the better. Belt materials do stretch in an impact (ask me how I know) and mounting the lap or shoulder belts to the floor makes them longer, not shorter.

 

Agreed. But I have a Planted seat bracket and I'm not sure where you would mount the sub belts. Also, even if you did use the seat mount, the difference in length would be about an inch, at least the way I did it. Probably not a significant difference there given the range of parameters given in the mounting instructions. Also, if it is a 6 point, Schroth recommends that the two mounting points be fairly close together and more or less straight down or slightly to the rear of the hole in the seat. Not sure that would even be possible using a Planted mount.

As for the lap belts, the difference is also negligible so belt length wouldn't be an issue.

There is no way shoulder belts should be mounted to the floor. They would be way too long and angles would be dangerous.

 

Attached is a pic from the Corvette forums (this may be where I saw it not the Evo forums.) Basically I was thinking to drill the front portion of the Planted bracket to accept eye bolts.

 

The planted bracket is pretty beefy. But the eye bolts are now getting put in a bending load rather than a pulling load that that were designed for in an impact.

 

Do you have any pictures of how you mounted your sub strap? I just finished a 6 point cage install on my drift Z and I want to run 6 pt harnesses. I am just trying to figure out how to mount them to the floor before I buy them.

 

No, I don't have any pictures. I just found the best place to drill the holes and drilled them. You have to take into account the seat position and the shape of the floor. Mine are positioned properly front-to-back but are a little wider apart than I wanted them due to the shape of the floor. I had some metal blocks that had the proper bolt hole size to raise the strap end a little off the floor. A couple of stacked washers would work just as well.