Roll Bar Fabrication. Advice on Mock-up Needed
 

I'm having a bar fabbed up for HPDEs, its tacked together now and I'm heading to the shop tomorrow to take a look. Does anyone see any changes that need to made? The seat is pushed all the way back currently, 4-5"s back from where I sit so I'm not to worried about the bar being close to my head in these photos. The other thing I'll note is that I'm going to reinstall the top so the down bars are a little steep to accommodate it. Currently the hoop sits even with the wind shield.


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How far above your helmeted head is the bar?

3"s with the seat pad, 4"s without the pad.

Not sure how far you are from VIR, but there's a race there on the 28-30th. There might be some boxsters there you can check out.

I don't see a horizontal bar for the shoulder straps?

I would want more angle on the support bars, tied into the rear shock mounts.

The shoulder bars were installed today. Unfortunately I'm keeping the convertible top so I couldn't tie into the rear towers.

I'll actually be at VIR this weekend, is there a spec race next weekend?

Pirelli World Challenge. That's mostly high end stuff but there might be a boxster or two in the lower classes

I don't think there's any PCA spec racing going on there this year but WRL will be there later in the year. I like WRL better because there's less rules and bigger motors. You also get to see boxsters beat up on other makes of vehicles

There is normally two or three whenever I go. Mixed between TT cars and spec cars test and tuning.

The diagonal is attached too close to the corner. Move it several inches to driver's right to give yourself more head room. You'll also want to wrap the whole head area with high-density foam, so you need room for that plus a helmet, and still be able to reach the headrest.

And as someone else said, you need the horizontal bar behind the seat to attach the harnesses, but also support the seat. That is a curved bar from the left vertical to the diagonal. And then from there to the right vertical a straight bar.

I can't tell from the pictures, but the attachments at the floor should be boxed. Tubes pushing through the floor when the car is upside-down is a common failure.

There's usually an additional diagonal bar from top-right to left-lower rear mount-point.

And then horizontal bars going straight back from the vertical bars to the rear mount points

You should be using 1.75” x 0.095” DOM, MIG welded.

Read the rules for inspiration:
SCCA
NASA
PCA