Seat mount tied into Cage:

#3

I guess if you welded tabs onto the trans side of the frame and bolted them to the car you’d achieve the same rigidity and safety without looking like you’re in there to “stiffen”, just mount. In fact you could actually mount the entire structure with tabs and bolts.

This approach is often used in NASCAR cars… I’ve seen where they ties the seat mount to the main hoop rather than the door bars with the same rationale you mention. “feet” on the floor are necessary to restrict “bounce” while in the seat.

Best advice - call the NASA National or Regional Tech Advisor - who is that? Not sure.

Kieran

#4

Thanks guys, appreciate the quick replies. I will talk to our NASA Tech to confirm, but it sounds like this is a reasonable request.

Thanks again! See you at the Track!
Nate

#5

technically, I think it adds another cage mount point, but I think this is something that should be allowed. I’m going to make some inquiries at national.
bruce

#6

Hey Bruce, I sent some emails inquiring, but any help would be appreciated. I truly believe this is within the spirit of the rules, there is no torsional rigidity gained from these small diameter, un triangulated bars. Rather, this is about safety; I would much rather have my butt tied to a DOM spaceframe than some .060" sheetmetal that was spot welded 20 years ago. :slight_smile:

Since I made that post this morning I am finding MANY GTS guys that do the same thing, the more racers I find with seat mounts connected to the cage, the more it makes me think that it is common practice and I am just spending too much time with the BMWCCA guys, haha!

Regards, Nate.

#7

I would argue that if you set the main hoop on plinth blocks and ran a cross tube from the plinth block to the tunnel for the seat anchor that you haven’t increased the cage mounting points. That sort of side steps the cage rules.

#8

jlevie wrote:

I would agree with you, but that is NOT exactly what I am trying to do, I am just trying to COPY the bimmerworld GTS seat mount design, which is pictured, as I believe it to be safer from an safety perspective.

Regards, Nate

#9

my (driver) seat and harnesses mount to little rails that extend forward from the main hoop, if you want i can try to grab a pic or two.

#10

Thanks Jason!

#11

I don’t really see how that would be safer than just welding the tubes from the trans tunnel to the body under the door. In fact I think it would be stronger attached to the frame than that small longitudinal tube. You could make that tube the same size as the rest of the cage though.

#12

turbo329is wrote:

There is not a substantial frame to tie into, the metal is thin, anytime you weld two substantially different thicknesses you are always balancing your torch, mainly focused on the thicker material; It’s just not ideal. Rather - you can have a joint with a perfectly notched tube with a much thicker wall, there just isn’t much comparison.

I will post up the results when I receive a reply from the tech steward.

Regards, Nate.

#13

The frame rail may be thinner than the tube but it is stronger due to the difference in diameter. A plate would work fine to spread the load more across the sheet metal frame. You didn’t say how thick the tube you planned on using was, but I assume it is the thickness of your cage tubing or less. If I was trying to add weight there I would do it your way, if I wasn’t I would do it mine.

#14

Not trying to argue really, it’s not even my car :slight_smile:

Just trying to provide the safest solution possible, nothing more. You are absolutely right about the weight though, we definately don’t need anymore left side at all.

#15

TOOLEAN wrote:

[quote]Not trying to argue really, it’s not even my car :slight_smile:

Just trying to provide the safest solution possible, nothing more. You are absolutely right about the weight though, we definately don’t need anymore left side at all.[/quote]
You saying I need to lose weight??? :huh:

#16

Z3SpdDmn wrote:

[quote]TOOLEAN wrote:

[quote]Not trying to argue really, it’s not even my car :slight_smile:

Just trying to provide the safest solution possible, nothing more. You are absolutely right about the weight though, we definately don’t need anymore left side at all.[/quote]
You saying I need to lose weight??? :huh:[/quote]

:dry: hahaha…I mean…it would help your cross weights, ha!

#17

this is the only decent pic i have http://cerient.net/photos/spec_e30/jan27/iphone_pics/img_0136.jpg.html

#18

Thanks for the picture, that’s exactly what I am talking about.

Clean car by the way.

Regards, Nate

#19

Sorry to burst some bubbles but this question was brought to me by Anthony who I then forwarded to our Regional Competition Director who then forwarded it to Jerry Kunzman. Jerry sent me a brief email asking what was the question so I sent him this:

Michael Osborne wrote:
“If a frame is fabricated to hold the seat and is attached to the cage (door bars or rear hoop) so as the seat moves with the cage but is also attached to the car (such as the tranny tunnel) is this allowed? Or would it be considered another cage attachment point(s). This frame to hold the seat will be structural.”

Jerry Kunzman wrote:
“It would be an additional mounting pt. In some series that doesn’t matter, however.”

So I would say it is not allowed in this series as cages are regulated. I would also say that the picture with the harness mounted to a tube from the cage to the tunnel would fall under his as well.

Sorry.

Michael
Great Lakes SE30 Series Director

#20

ilateapex wrote:

[quote]Sorry to burst some bubbles but this question was brought to me by Anthony who I then forwarded to our Regional Competition Director who then forwarded it to Jerry Kunzman. Jerry sent me a brief email asking what was the question so I sent him this:

Michael Osborne wrote:
“If a frame is fabricated to hold the seat and is attached to the cage (door bars or rear hoop) so as the seat moves with the cage but is also attached to the car (such as the tranny tunnel) is this allowed? Or would it be considered another cage attachment point(s). This frame to hold the seat will be structural.”

Jerry Kunzman wrote:
“It would be an additional mounting pt. In some series that doesn’t matter, however.”

So I would say it is not allowed in this series as cages are regulated. I would also say that the picture with the harness mounted to a tube from the cage to the tunnel would fall under his as well.

Sorry.

Michael
Great Lakes SE30 Series Director[/quote]

Thanks for the clarification, no reason to appologize, that’s why I asked FIRST. But I was under the assumption that GTS and SE30 had to follow the rules for the cage, I guess I was wrong.

This maybe something for you guys amend for next season, as it seems to be an area of improvement.

Regards, Nate

#21

Coming from a circle track (stock car) background, I was VERY surprised when I saw how NASA and SCCA allow seats to be mounted. I was always under the mindset that in a bad crash, you want the seat mounted to the cage. That way, if you are harnessed in and the harness is attached to the cage everything moves together and you are safe. Now, if you have your seat mounted to the floor pan, harness mounted to both the floor and the cage, as most are, and you get into a bad wreck, the cage moves one way and the car/floor pan could move another. See where the issue lies? My new car is using an adjustable setup for now or else I would have a full seat mount welded to the cage along with seatbelt tabs. I still feel this is the safer way and hope moving forward, the sports car guys change the rules to reflect this.

#22

I’m bring this back from the dead. I’m currently building the cage in my car and would like to tie the seat mount into the cage. How can I do it legally?