Happy Birthday to me (280z build)

Re: Happy Birthday to me (280z build)

Postby 3rdgendennis » Tue Nov 29, 2016 2:20 pm

drummingpariah wrote:I'm using Larson's old seat, which is expired so I'll need to add the rear reinforcement to the cage. I'll probably just run the harness bar behind the main hoop, with bends at each end of it. Nothing too fancy there.


As far as I know, FIA seats are good "forever" under all current rules. Not saying not to brace it (proper bracing is safer even when it's not required), but the expiration date on FIA seats doesn't mean much.
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Re: Happy Birthday to me (280z build)

Postby walterclark » Tue Nov 29, 2016 5:02 pm

drummingpariah wrote:I'm using Larson's old seat, which is expired so I'll need to add the rear reinforcement to the cage. I'll probably just run the harness bar behind the main hoop, with bends at each end of it. Nothing too fancy there.


I know of no racing rules in the US that accept the FIA seats and recognize that they expire. So technically you can use them until a scrutineer says the seat is damaged and must be replaced...or rules are amended to recognize the FIA 5 year homologation expiration and require replacement.

I would recommend you NOT attempt to add a back brace to an FIA seat unless the manufacturer specifically allows it and provides guidance. I really doubt they will. I checked with Sparco and Cobra...nope. Adding additional mounting points or a back brace can cause a more dangerous situation in an impact than if left alone since the seat was not engineered for the new loads at the attachment points.
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Re: Happy Birthday to me (280z build)

Postby drummingpariah » Tue Nov 29, 2016 10:46 pm

That's interesting. I'm really glad Steve asked now!
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Re: Happy Birthday to me (280z build)

Postby 3rdgendennis » Thu Dec 01, 2016 3:59 pm

walterclark wrote:I would recommend you NOT attempt to add a back brace to an FIA seat unless the manufacturer specifically allows it and provides guidance. I really doubt they will. I checked with Sparco and Cobra...nope. Adding additional mounting points or a back brace can cause a more dangerous situation in an impact than if left alone since the seat was not engineered for the new loads at the attachment points.


Good point
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Re: Happy Birthday to me (280z build)

Postby drummingpariah » Fri Dec 02, 2016 10:01 pm

I didn't really plan to get anything done today, just clean up the shop a bit in preparation for the weekend. Man, was I wrong. I nailed the passenger side A pillar so nicely, I decided to make another driver's side replacement ... but twisted the wrong way, which resulted in another perfect passenger's side A pillar. Then I made one more driver's side, and went so far as to add a small bend on the back of it to get it to fit up with the main hoop just so.

Tomorrow, I get to break out the welder, tack it together, and start in on reinforcements.

Image
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Re: Happy Birthday to me (280z build)

Postby drummingpariah » Sun Dec 04, 2016 12:49 am

Finally, everything's aligned and tack welded into place. I spent most of the day fine-tuning fitment so it's symmetrical on both sides and so I have as much headroom as possible, but the results are worth it.

Image

All told, I bent 6 'not quite right' A pillars throughout this process, so roughly 40' of material that didn't make it onto the car. It'll all get used, as door bars or similar.

Image
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Re: Happy Birthday to me (280z build)

Postby drummingpariah » Sat Dec 17, 2016 7:25 pm

My friend Mike and I started off by finishing coping for the dash bar, which looks pretty much ready to tack in place now.
Image

After lunch, Mike took care of the sill bar coping and I took care of the bent door bars. They aren't quite ready to weld in, but we're making good progress.
Image

Unfortunately, we ran out of material for the remaining sill/rocker bar and the windshield bar (both are required to run Mt Washington). I'll have another 24' arriving Monday morning. Tomorrow, I think I want to set our sights on tackling the front suspension jig, since the 'core' of the cage structure is finally coming together.
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Re: Happy Birthday to me (280z build)

Postby dsldubn » Mon Dec 19, 2016 12:59 pm

looking good!

What is the main "frame" of the car going to be constructed from? Looks like your cage door bars and sill bar sit really low, so was curious.
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Re: Happy Birthday to me (280z build)

Postby drummingpariah » Mon Dec 19, 2016 3:17 pm

Good catch. In the photo, the sill bar is at the stock 'frame rail' height. We're in the process of moving the whole floorline of the car around 5cm higher than that. It meant cutting the main hoop diagonals back out again, and coping new ones. I'll call that an hour well spent, but it means the X in the center isn't perfectly perpendicular any more.

Originally, I wanted to make sure there was plenty of room for drivers of any height to hop in for a test drive. After mocking the seat up relative to this floorline, my friend Joe couldn't see over the bottom of the windshield ... and he's 6'2". I'd have to put a booster seat in it for a Tingaud to drive comfortably.

The higher the floor is, the lower I can place the center of gravity without hurting ground clearance.
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Re: Happy Birthday to me (280z build)

Postby drummingpariah » Sun Jan 01, 2017 8:16 pm

It's been a ton of extra work, but I made new sill bars and X braces, and am just starting to catch back up to where I was a couple weeks ago.

We went from this:
Image

to this:
Image

It looks like such a simple change, but was a pretty massive effort. On the positive side, I'm getting quite good at coping with an angle grinder now!

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