Nov issue - Roll bar install

IMHO - you left out a few things.  #1 - the height of the cross bar has to be no more than 4" below the driver's shoulders.  #2 - the fine print in the rule book says that when you weld the cage to the floor using plates, the two angle braces under the main hoop (labeled "D" is the diagram) are mandatory.  
1967 Falcon 4 door - 351C
1970 Mustang coupe - 351C
http://raceabilene.com/kelly/hotrod
Owner built, owner abused.

Read it again. The girls distracted you.  

I see now the seat belt note.  IMHO, you still missed the two extra braces.  Don't give me any chickie-baby crap - I just finished a roll bar install in my WIFE'S race car. If I need photos I can Google "chicks with cars".

Both NHRA and IHRA tend to contradict themselves on the roll bar issue.  I've complained, NHRA ignores you and lets their SFI certified inspectors go with whatever they think.  I can at least have a conversation with IHRA.  The books make a distinction between a unibody and a full frame car.  No frame, you can bolt or weld the main hoop to the floor.  Most people put subframe conenctors in a unibody - the book says specifically that subframe connectors are not a frame.  Then in the bar location diagrams they instruct you that the side braces are manditory when the main hoop is welded to floor plates (unibody installation) and "must be connected to frame".  

If you local inspector passes it, go.  If you've seen a close up of what a broken suspension part does to a Camaro/Mustang size car at 88 MPH in the lights, you'd put in more bars.


That's her car, BTW.  400 HP 351C, runs 7.50s in the 1/8 near sea level.  
1967 Falcon 4 door - 351C
1970 Mustang coupe - 351C
http://raceabilene.com/kelly/hotrod
Owner built, owner abused.

Falcon67:
I see now the seat belt note.  IMHO, you still missed the two extra braces.  Don't give me any chickie-baby crap - I just finished a roll bar install in my WIFE'S race car. If I need photos I can Google "chicks with cars".





Good photos (of the roll bar . . . the swimsuit stuff was just a waste of space)!

Now for the dumb questions to CC mag (or anyone else who wants to answer):

1. Why is it that almost nobody ties the main hoop in with the door jams and (if not a hardtop) the B-pillars?  Herb Adams used to recommend that in his F-Body "cookbook" back in the '80s.

2. Why is it that none of the "how to install a roll bar" stories ever seem to cover building a "multipurpose" bar that will pass inspection for drag racing, open track events (usually run under NASA or SCCA rules) and Bonneville/ECTA/high speed challenge?   (I'm aware the requirements are different -- but there are a few "jack of all trades" cars out there. And there are plenty of folks who like the idea of a multipurpose street/track vehicle.)


3. Why is that none of the "how to install a roll bar" stories ever show some way of keeping usable access to the back seat and complying with the rules?  Although I've never tried to get it past tech, it seems to me that a diagonal brace on the main hoop together with a fixed back brace between the diagonal brace and the driver's side of the main hoop and a removable back brace from the passenger side of the main hoop to the diagonal brace would be both safe and legal. Am I wrong?  
*****
TURBO TED --Internationally known as the "John Force of the Yugo Racing Association."

Sergeant-at-Arms and immediate Past President of the SoAL Yugo Owners Group.

1) Because the main hoop almost never lines up with the door jams.  On her car, the hoop is forward of the jams by about 3", on my Falcon it's back about 3".  And it doesn't add any strength to the car, really.  

2) I'll leave that for someone else, I drag race and have no interest in the other.

3) I'm not pictureing exactly what you are describing.  The object it to prevent colapse of the main hoop.  It has to be stiff, and triangulated.  I don't even like swing out door bars, personally, and none of the cars here use them.  I also would not leave out the passenger side door bar, even though the diagrams indicate you can.  I adjust the door bar to meet the rules and we can both get in and out easy enough.  Her car has to have a removeable steering wheel because I can't get in it with the wheel on (she short, me tall) because the seat is so close to the column.  I don't think a break of some kind in the cross bar would leave it stiff enough to help brace the hoop in an accident.  I've seen too many crashes at the strip - good bars save the driver, bad bars hurt the driver.  

As for the back seat - Probably because unless you run a 4 door like me, there's no use for the back seat after a bar is installed.  I used "street bars" in the Falcon:


and can use the back seat - but I have doors back there. I was going to use street bars on the Mustang, then just needed to "get on with it" to get the car back on the track.  I am glad I didn't bother - yes, I could get the seat cushions back there, no - no way anybody could sit or get back there.  It's a serious PITA for me to monkey myself into the back seat area on that car now.  No way to make it usable space IMHO.
 
1967 Falcon 4 door - 351C
1970 Mustang coupe - 351C
http://raceabilene.com/kelly/hotrod
Owner built, owner abused.

Thanks for the thoughtful reply and the photos of your Falcon.

1. Your point on alignment with the door frame is well-taken. But Herb Adams (a GM-trained chassis engineer) claimed that tying the bar into the door jams did add strength to the "flexi-flyer" Gen II F-bodies of the '70s.  Perhaps it's easier to line up the bar on an F-Body than it is on a sedan. Or it could be that he was more of a road racer at heart and worried more about chassis flex than most sportsmen drag racers.

2. You've probably answered my second question -- Magazine editors probably aren't interested in multi-purpose cars either.

3. A drawing would be worth a thousand words here . . . .  What I suggested is triangulated . . . even more than the standard drag set-up, because it has a "road race style" diagonal bar running from the driver's side top of the main hoop to the passenger's side bottom of the main hoop.  Only the passenger side of the horizontal cross bar would be removable.

As to whether it would be stiff enough during a crash, a significant amount of the forces would be transmitted to the diagonal bar.  The cross bar would be in compression when loaded by impact.

Like all other pinned or removable bars (which I gather you don't like), the passenger half of the horizontal cross bar would only be as strong as the pins and their receiving brackets.   Receiving collars could help "capture" the removable portion of the bar in the event of a pin failure.  However, a side impact serious enough to break a pin probably has enough g-loading and other intrusion to put the driver in jeopardy regardless of what the removable section of the cross bar does.

4. As for the back seat: it's true that nearly every bar set-up compromises rear seat leg room and access.   But there are plenty of folks who want to keep the back seat and so there ought to be some legal way to make it work.  

We're not talking about arthritic granny/taxi cab-level access here.   A fixed horizontal crossbar would challenge even a pocket-sized olympic gymnast to access the back seat.

Anyone else have any thoughts or experiences?

Douglas?  
*****
TURBO TED --Internationally known as the "John Force of the Yugo Racing Association."

Sergeant-at-Arms and immediate Past President of the SoAL Yugo Owners Group.

i have seen a usable rear seat in a car with a 10 point cage

the car was an 89 mustang...convertible...well it wasn't a convertible after the cage went in...it had no top and a piece of material was fabbed up to simulate a convertible boot  
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the red-headed step-child of the mailing list

fuzzy dice, air shocks & N50's rule

I see what you mean now.  That might be just fine, but for drag cars it would have to be added to the rule book because the diagrams are pretty specific.  I have seen pics of a similar configuration from "the old days".  The current config - IMHO - is designed to protect the driver and keep the roof up and the sides mostly where they are.  The last bad roll over at our track was a ladder bar failure in the lights.  One bar dropped and dug in to the track past the beams, flipping the car up and over.  Several rolls, much damage.  The only sheet metal that was still straight was the trunk lid - the bar kept the car that square.  Front sub frame torn loose, floor bent, subframe connectors bent, and the main part of the body sheet metal was basically molded around the roll bar inside.  The main hoop was tweaked, but it all held and the driver walked away.  Car was scrap metal.

Drag racers like a stiff chassis and an 8 point bar with subframe connectors on a unibody really stiffens things up.  10 and 12 point even more.  You add 100 lbs to the car and like as not you'll pick up ET from the installation.

I'd like to have put the back seat in the Mustang, I was just pointing out that with the bar installed per the book, even if the cushions were back there only a very small person could worm their way back there.  And only because -in this car- of the short driver and the hoop being forward in the car.  If the Mustang bar was fitted to me (6' 1" 210 lbs) , you might not get the seat in at all because the main hoop would be too far back in the car.  In my 4 door, I put the back seat in for shows and such and the lower cushion wedges against the hoop real tight.  Another inch back and it would not have fit at all.  

Caveat for all this - this is with an off the shelf bar that basically echos whats in the NHRA/IHRA rule book.  Take the car to a good custom shop and tell 'em what you want - you'll be light in the wallet but likely have access to the back plus a legal cage to boot.  A good custom bar install should run about $1000+.  Get it certified for competition by an inspector for about another $100~140 (even if you are not that fast) and you should have no problems with tech anywhere.

FWIW - The Mustang bar is an S&W Race Car item (so is the one in the Falcon) and was $169 plus shipping.  Tubes were already notched and install was straight forward.  The most engineering for the Mustang was building a pair of "risers" to give the main hoop a firm level foundation.  

And also - I'm putting in .130 tubing, sitting on .125 6x6 steel plates.  All this heavy duty metal sits on 18 gauge sheet steel.  What's gonna give first - ya, the floor.  The hardest part of the install was getting enough heat on the edge of the .125 plates to bond the metal to the floor steel without going into "plasma cutter" mode.  .030 wire, voltage and wire speed down, make a puddle - STOP - make a puddle - STOP.  Repeat 26,437 times.  
1967 Falcon 4 door - 351C
1970 Mustang coupe - 351C
http://raceabilene.com/kelly/hotrod
Owner built, owner abused.

This is a good thread.  Lots of good points.

It would be good if CC did more safety equipment install stories, too.  
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460_BBF_Turbo-in-CC (formerly Dr511scj) "This guy has no life other than posting endlessly on carcraft.com." -- Car Craft, July 2005
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October 1, 2003: " I'm thinking a couple of...turbos, blowing through an old Powerstroke intercooler...on a Super Cobra Jet-head 460 would be mad cheap and make sick power."
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"I have no problem with your...talking to several versions of yourself...or pointing out our failure to do a turbo story ...." --Douglas "CC/Rambler" Glad

Hey guys, is it just me or are the welds in the photos of the cage article a little bird crap and bubble gum looking .  The Kartek welds on the new exhaust are how Mig welds should look like, maybe Eddie should have welded the cage for you. Other than that the article was great.