Door bars that miss the window crank and door handle

[RebekahsZ]

Hoping to get a few opinions on a few door bar designs I've taped up.  Seats and old Autopower bar are pulled out, getting car closer to being ready to go to fabricator for a 10.0-certifiable NHRA roll bar.  The main hoop will go to the floor and the rear supports will go to the strut towers.  No strut tower brace in order to allow hauling tires to the track (I don't want to lose the cargo space).  I have seen lots of photos of door bars in cars that either have the doors removed or at least opened.  I'm going to run doors and close them when I race, so I want to be sure that I have access to the handles after the bar is installed.  I am also curious as to opinions of the stiffening "bang for the buck" effects of door bars that have diagonal braces to the firewall.  If the benefit of a bar to the firewall is minimal, I may just run a single door bar and screw it on any stiffening concepts/goals.  I hope to add a dash bar / knee bar to improve side-impact safety next year when I have the dash out for a clutch pivot freshing and nicer gauges.

[LanceVance]

I've planned on removing the factory handle from the get go, though for different reasons. If you examine the linkage system in the door it quickly becomes apparent how easy it would be to convert, or even simply add (if you wanted to still retain the stock handle) a cable operated portion to the stock bits. Something similar to the Porsche Carrera RS isn't terribly difficult to put together, and could be put wherever is most convenient.

 

I've got most of the parts ready to go in storage, the door 'roses' from most Porsche parts suppliers are surprisingly affordable!

 

Edit: Just convert to electric windows! I know someone on here showed that the electric conversion actually shaved weight! Win-Win in my book.

Edited January 12, 2014 by LanceVance

[RebekahsZ]

Oh, but that puts another project between me and going fast. Trying to avoid the domino effect.

[johnc]

The braces to the firewall are there to keep the footwell intact in a collision. They protect your feet. You will have to mock up your door bar options to see which best clears the door latch and window cranks. Buy some 3/4" conduit and a conduit bender and have at it.

[RebekahsZ]

Thanks, johnc for the clarification.  Do you think that any of those door bracing strategies has ANY more chassis stiffening promise than the others?  Or do you think they are all kind of pissing in the wind? 

 

I can see from jacking up my car that the chassis is a noodle, and I was hoping to help some with the accessory bars to the firewall in the area where the front inner fenders join the firewall using as large a footplate as possible (pretty crowded up there).  If all those options seem pointless, I might stay with a simple 6-point and save weight and entry/exit difficulty.  I do plan a knee bar passing thru the radio portion of the dash, but that addition will be staged, probably next winter. 

 

Now that the brakes and shocks are done, it is full-court press on the roll bar-I expect to fire off a seat and seat brace order tomorrow after work.  Once that arrives, it's off to the chassis shop.

[johnc]

A roll cage is primarily for safety.  Door bars and the firewall brace can add some stiffening but design them first for protection and easy access.  An "X" is the easist to build and does the best for stiffness but makes access more difficult.

[Turbo Meister]

Just get an 8.50 cage...you know you will want one or two turbos in the future. My custom cage provides door bar clearance because I wanted to maintain street use.

[zbloke]

The door bars on my cage still give access to the window cranks and interior door release levers 

 

Weather they'd be legal for your 10.0-certifiable NHRA roll bar is another matter though......

 

 

[RebekahsZ]

Thanks so much for the photo.  No, those bars need to angle up more toward the rear of the car.  NHRA requires that the bar be closer to the shoulder (I can't recall if it is between the shoulder and the waist or the shoulder and the elbow).  Otherwise, that looks like a nice cage, and it would take very little to make it into an 8.50 cage.  It looks like you have worked on the seat mounts??  Do you hit your head on the front leg of the cage when seated?

[RebekahsZ]

Thanks, Turbo Meister.  But, so far, I've been able to control the "just a little bit fasters."  I'm gonna limit my power mods to a cam and spray in the years ahead.  If I really wanted to do better at the track, I'd put a power glide in it and win some bracket racing money.  The guys winning money most regularly at my track are a heck of a lot slower than I currently am.  They are just better than I am.

[74_5.0L_Z]

Here are some pictures from my chassis construction in 2003:

 

 

 

The chassis is very stiff.  I can jack up the car under the front sway bar attach point and get three of the four tires off the ground and still open and close the doors.

The X across the doors is low enough that I can roll the windows down (the factory crank just rubs the bar as it passes).  I did have to delete the 260Z armrest though.

 

 

Edited January 14, 2014 by 74_5.0L_Z

[zbloke]

 It looks like you have worked on the seat mounts??  Do you hit your head on the front leg of the cage when seated?

 

I'd already modded the seat mounts before the cage went in, but its pretty safe to assume my head would have hit.....even with the modded mounts my head would just clear when rolled to the right and with helmet on it would hit the cage

 

I've different seats fitted now, pics are in the "Will Recaro Profi SPG....." thread in Interiors, head is well away from the cage.....and I feel much happier

[RebekahsZ]

Thanks, 74_5.0L_Z.  Can you shoot a photo of the inside of your passenger door (with the passenger door shut) from the driver's window (or open door) so that I can see how those x-braces criss-cross across the door panel?  I haven't had an arm rest in years, either!

[74_5.0L_Z]

Here you go.  I'm sorry there so dark,  but I stink with a camera and the car is dirty from sitting these past two years.  The second picture shows where the door bars penetrate the firewall to attach to the front.  You could probably weld a plate in that corner to attach the door bars to if you didn't want to penetrate the firewall or if you don't want a front hoop.

[RebekahsZ]

You might just be the best dude on the planet! Wait-you don't have a FULL cage?? And Ive been somewhat ashamed of wanting only a bar and reinforcement.

[74_5.0L_Z]

My door bars attach to a hoop forward of the firewall.  Its kind of similar to the way some roadster cages are made.  When I built my chassis the car was still being driven regularly on the street.  I didn't want halo bars to rattle my brain.  For a purpose built track car, a full cage is the best solution.

Edited January 15, 2014 by 74_5.0L_Z

[RebekahsZ]

Yeah, instead of a purpose-built car, my z is more of a compromise-built car!  Next year, my big project will be pulling the dash, new gauges, welding and re-drilling pedal pivots and organizing wiring.  At that time I also hope to add a cross bar from one set of door bars to the other, probably passing under the glove box (AKA the "timeslip box, reading glasses box, shock adjuster knob box, flashlight box, 2-step and shift light adjuster screwdriver box, 9/16" pedal switch adjustment wrench box, and 7mm and 13mm clutch pedal adjustment wrench box, and tire gauge box") behind the radio in front of the heater and under the steering column.

Edited January 15, 2014 by RebekahsZ

[Turbo Meister]

This is my setup...ignore the well-worn steering wheel!

[RebekahsZ]

Thank you. Looks great.

[SUNNY Z]

This is good. Will definitely be pulling pictures from here in a couple months when my car goes out for the cage