Hey Todd, is that your sway bar mountiing plates beside the break? (Hard for me to get my bearings in those pics.) If it is I wonder if it played a role in this failure.

Don

Don, I really don't think so. I haven't had a sway bar on it regularly since putting the BFG tires on it well over a year ago. Even with the r888's, I don't need one anymore since switching to stiffer springs after Optima. The sway bar only add's about 75-100 in/lbs anyway.

Good discussion, lots of concern, lots of opinions.... But you hit the nail on the head, and I'm glad it came to this final thought. "Original GM frame rail metal thickness and over usage for intended design"

Based on your attention to detail, It will be 10x stronger when you are done with the repair. I like your style.

Brett

See, you never have to wonder what is next on the car, it will always let you know what it wants.

That blows but glad you found out now brother---I will keep an eye on mine in the future once the car has sticky tires and more than 238 Ft Pds.

Rodger's car must have been faster and had more torque, his broken frame rail was like way more broken than yours. :lol:

Let me know if you are def coming out for the Calif Speedway deal---my place is available if you need it--hoping to have my car ready for that event as well.

D

No, No... that's not always true for everyone. Only if you have an Apollo type relationship with your car. :rofl:

Big Wanda, I'm making that race! Not sure I want to drive to Lake Forest every night. Thanks for the invite....:cheers:

Here's a quick design for a gusset. My thought is to over lap the cradle the same distance on each side of the outside of the frame. Along with a diamond shape that would be welded to the cradle on the bottom side, tack welded in every hole, and welded to the top of the frame rail/body. I'm also going to radius the sharp outside edges so I don't create any points.

The current crack will be tig welded and ground smooth.

I'll likely make it about another 1" longer to cover the body plug hole and get closer to my sway bar mount. Let me have it....
http://i200.photobucket.com/albums/a...rameGusset.jpg
http://i200.photobucket.com/albums/a...Gusset1004.jpg

That's a good plate design,I would use the same amount of holes only around 5/16 dia. A plate w/9/16 hole's might allow the surport plate to fracture sooner(plus larger holes mean more welds and more heat it the weld zone..A smaller hole will allow the plate to provide more of the surport needed.Keeping the end's of plate angled will not let the frame rail shear as easy.:thumbsup:

I agree but, tie it in to the sway bar mount and weld it out too.

"My old man is a TV repair man, he's got an ULTIMATE set of tools,....... I can fix it!":unibrow:

Personally -- I'd plate all three sides...


I stayed at a Holiday Inn Express last night --- so I'm a chassis engineer today.


EEEEEEEEEEEHHHHHHHHHHHAAAAAAAAAAAA

Russ called me back this afternoon. He's got a full time gig but offered to fix me up the weekend after next at his father in laws shop. That just happens to be about 5 streets up the hill. :D

I redesigned the plate to be longer with a radius and smaller holes. The frame is already basically plated on the inside with the cradle but I agree, I'll have Russ add some metal to connect the cradle to the exterior plate on a longer run to distribute more load.
http://i200.photobucket.com/albums/a...1969/001-6.jpg

Great design! I recommend boxing up all 3 sides :thumbsup:

Glad to hear its gonna work out!
Because I was definatly looking forward to you spanking that brad penny!lol

Todd,that design looks real good.:thumbsup: Scott M.

As many of you know, I've been fighting some pretty wicked brake pad knockback since I built the car. Part of dealing with it this long is do to procrastination:D , but it was mostly due to figuring out an economical solution that didn't have to many side effects. Like a full floating rear end that needs serviced way to often, loss of my internal parking brake(Which I really like and use), looked good, and didn't break the bank.(I've already got to much money tied up in this car. :lol:

Big thanks go out to Dustin Burr at Wilwood engineering. We talked and came up with an economical solution. What I did was adapt a GM metric caliper fitment to the rear of my car. A metric caliper came on the front of a boat load of cars from 68 on up. Wilwood just came out with their own version that looks great and maches my fronts well. This is a floating caliper design. It was important that I kept the e brake set up but Wilwood doesn't make a bracket to adapt this caliper to there parking brake set up. Dustin hinted around about a company that does and I have to keep that a secret. They don't normally sell this bracket individually so we'll just leave it at that.

This is as step DOWN in brake performance. Meaning, full out road racing and heat disipation. I stepped down to a 12.2" x .81 rotor. (Old was 12.98 x 1.01)They offer the caliper in 3 piston diameters. I picked a diameter slightly smaller than what I had before. My thought was that I feel most of these cars are built with larger brakes than needed out back. Take a look at any Corvette, minus the c6 z06. It's only 30% of the braking. I feel it will meet the needs of my car. I don't endurance race.
http://i200.photobucket.com/albums/a...kBrakes002.jpg
http://i200.photobucket.com/albums/a...kBrakes001.jpg

As usual, when you put your own swing on things, it comes with it's problems. Just a couple little things to make it work. The brackets I sourced were to tight to fit over the caliper so I had to clearance them and come up with my own spec of how loose I wanted them. A steel bracket and aluminum caliper made me a little nervous due to the difference in expansion rates. I settled on .015 as a minimum on each side. I was really scratching my head mounting up these brackets. I knew the spacing was wrong. Turns out they forgot to send the spacers and hardware with the brackets. Once I recieved teh missing link, things went well. I didi find the center mounting bolt to pass into the e brake slide so I ground the bolts down about 1/8 so the e brake shoes could move as designed.
http://i200.photobucket.com/albums/a...kBrakes003.jpg
I'm really happy with how they look. I took her out for a ride tonight and it stops great. The pedal is high and hard. I put it through the paces that would've induced the pedal drop in the past and I was only able to detect a hint of knockback. If the track results back this up. I'm going to be a happy dude! I'll report back after my next event.
http://i200.photobucket.com/albums/a...kBrakes010.jpg
http://i200.photobucket.com/albums/a...kBrakes009.jpg

Hope that solves the issue once and for all. Be interested in hearing the after action report on this fix.

Way to keep after it brother.

:thumbsup: :thumbsup:

Good luck,At your next racng event.:thumbsup:

So was Kelly helping you, or are you one of those guys that don't like to get his hands dirty?

Is this a single, dual, or four piston caliper?

The continued pursuit of perfection.... :thumbsup:

Hey man, I like getting greasy like the next guy. It's just a little embarassing having greasy finger nails when you are supposed to be a professional.

It's available in 3 piston volumes. The smaller calipers have 2 pistons while the largest is a single bore. It's floating so no pistons on the outside.

Great upgrades and I hope it cures the problem Todd. It's a floater so it should. Good looking caliper IMO too. I also would think 3 laps around RTTC would not create a heat/brake fade issue, but longer sessions (20 min SOW) maybe?

Gaetano should chime in here; he told me his rotors 'pop' during cool down sessions...

It's all speculation at this point. All I know is, anything is better than what I had.... Until you experience serious knockback on the track, it's really hard to understand. It throws off your timing and greatly decreases brake performance. I still think the fronts will fade before the rear. Remember, braking is 70% front, 30% rear. I don't have any intentions to run past about 15-20 minutes on an open track. My car simply isn't engineered to go any longer than that anyway.

Hopefully this fixes your brake problem. Good luck!

REALLY?? That's never been an issue for me...



EEEEEEEEEEEEEHHHHHHHHHHHAAAAAAAAAA:woot: :lol:

We really need a few more smilies around here... :D

I hope it works out for you Todd, you put plenty of work into getting it right. Are those calipers comparable in size to the regular C6 calipers?

Well I welded in my Airbar and now you have me all freaked out....thanks :)

Was the plate welded all the way around the perimeter or just in certain spots? I noticed that the bolt holes were open....

The Airbar is a bolt in deal too.....its held in by 10 self tapping bolts....

I'm no engineer, but can anyone honestly tell me that 10 self tapping bolts into thin ass original frame rails would have held up any better? I would think that they would have just ripped out of the frame

So....looks like I'll be adding some extra support.......

You'd have to actually drive it... and have 600+ HP.... and big azz sticky tires... and track the crap out of it... so if you have all that going for you... then you "might" break your frame.

NED -- Here's what you SHOULD BE worried about.... Watch ALL the video. :woot:

I'd add frame gussets now since you are in fabrication stage. I have some brackets being cut and they will be welded in this week. I'll take some photos of the finished product. I don't like the sharp points this cradle was designed with. They could've easily been half moon shaped. That being said, with the way I've driven the car, it's not the end of the world.

Sorry to hear about your cracks in the rear frame-rails Todd. Looks like you have a good fix in boxing up the other 2 sides. :thumbsup:

Guess that is another another thing to add to my to-do list. I always wondered given how thing the rear frame-rails are what it would take to break them.

Yeah yeah....by the time I'm done with the car, the frame will have melted away from global warming...:)

I will have close to 600 HP....335 in rear but not as sticky of a tire....and the car will get abused but not nearly what Todd does I'm sure..

All last night I was trying to come up with plans for gussets or other braces to act as a counterforce for the bracket pulling on the frame etc. I think that at the minimum I'll add a plate to the outside of the frame that extends past the ends of the bracket.

Todd...yours is the g-bar? The pix I pulled up look like a different design than is under your car but I may be wrong. I pulled it up online to get a more global view of where the system attaches and spreads the load.

One thing I did notice is that the Airbar system frame bracket has longer horns on each side of where the tube attaches to the frame plate. The g-bar and g-link have those attachements pretty close to the ends of the frame bracket.

Good point. And then we freaks add to the problem by mini-tubbing our cars and cutting right into that weak point. When I looked at cutting into the frame rails, I said F'that and had 1/4" steel plate put into the thin area. This may come back to bite me, as now the flex will be transfeered to the weak, non-reinforced frame rail area. I guess if that happens I'll be calling Todd to fax me a template...:yes:

Ned, my G Bar is an Air Bar with varishocks. Simple as that. The design for the Cuda is likely different to some degree. Once I get the brackets and they are welded, I'll post it up to jog your mind.

Ron, You are running the quadralink which is a big difference in design. It has a panhard bar vs. triangulated upper links. I haven't seen anybody break a frame yet with a DSE set up. Doesn't mean it hasn't happened but it seems to be a more natural design for the frame rails. That would be the area you need to keep an eye on... I doubt you have any problems but it you do, congratulations. That means you have put many a beating on that purty car. :D

With the AirBar for my car, the front section of the tube that has the upper forward link bracket attaches to the floor rather than have a bar that goes all the way across.... they supply plates to go inside the car to spread the load. The first design they had used small L plates and some people ripped their floors....so they made them bigger and all one piece.... I reinforced mine and made them even bigger

The G-bar has a crossmember tube that goes all the way from frame bracket to frame bracket for both the shock and the UCA, right? Mine doesnt... yet :)

Ned I don't think you have anything to worry about, whatsoever, with the way yours is welded in. You'd probably be pulling 2Gs and snap an axle shaft off before you would move that thing, LOL


*Edit* and, if you change those mounts and then as a result we have to make some new brackets for your exhaust....I'll kill you.

[quote=GregWeld;356615]NED -- Here's what you SHOULD BE worried about.... Watch ALL the video. :woot:




LOL! Not many truck frames get bent in THAT direction!

Todd I agree 100% w/regard to rear brakes (30% of the equation) and this should be a very effective solution for your knockback issues.

Floating calipers exist in the OEM realm for a reason, after all.

I wonder how long it will take before Wilwood, Baer, etc, bring a large-format floating caliper configuration to the market, since many people clearly want really large rear brake setups for various (mostly aesthetic) reasons.

But then again, how many folks actually track their cars, and become concerned with knockback....