The Elephant In The Room: unloading the load from a B-body.

[Mopar John]

So after a break back to my "BITTER LIME" GTX weight loss program!
When we left off the GTX was down to 3029 LBS and my goal then was 3000 LBS!
At that time I had about 6 front K members laying around from parted out cars.
I decided to take one of the rougher ones and start trimming the clamping flanges with a cutting wheel.
I got about half of it trimmed off and went and had that area seam welded.
Then I went back and trimmed the rest off along with some of the bracing for the motor mounts and steering box.
Then I got the rest seam welded. The result was a weight loss of 12 LBS and now down to 3017 LBS! WOW!
At the same time when I installed the light weight K member I installed non sway bar lower control arms.
That resulted in another weight loss of 3 LBS and now down to 3014 LBS.
During this time I also swapped out some hardware for 2 more LBS and down to 3012!
3000 LBS here we come!
I have attached some before and after pictures of K members with and without the clamping flanges.
MJ

 

[rmchrgr]

About 15 years ago a guy named Bondo Bob from somewhere in Ohio was modifying stock K members. He'd cut out the middle part and put CM tubing in, it was like half stock/half tubular. He was making tube front ends for a while too. Have not seen him on Moparts in a long time, not sure if he is still doing this.

These are not my pictures, I saved them from Moparts. I don't know who's work bench or car this is either, just showing the pics for illustrative purposes. They are different too, one has tow hooks on the sides.

I thought it was a cool idea and I probably would have considered doing it myself until QA1 started offering tubular K frames. Obviously this one requires a motor plate.

I had a spool-mount K frame that I've had for many years. Someone before me started cutting the flange off but they used a torch and made a mess. At one point I was going to finish the job. I made a jig to keep it straight and everything but it was a lot of work and I gave up. It's been sitting on my shelf for like 15 years. Maybe I'll re-visit it one day.

Perhaps DVW will chime in and dazzle us all with pictures of his immaculately trimmed and smoothed K frame in his Bad Penny car. It's a work of art.

 

[Mopar John]

Great reply rmchrgr!
At that time I trimmed mine the tubular stuff was mostly junk with bump steer issues!
With the weight of my K member so much lower I havn't justified the high cost of the new stuff!
I hope others show their stock K frame mods!
MJ

 

[rmchrgr]

Here is the QA1 K member in my Duster. By itself, their K frame essentially weighs the same as a stock one. They claim that if you use their entire front end, (tubular A arms, tubular LCAs, adjustable strut rods) you save 18 lbs off the front. Most of the weight savings is in the strut rods though which are aluminum. The QA1 K does provide more room though so there's that.

The QA1 K frame and lower control arms both automatically come with sway bar brackets built in. If you ditch those pieces I'm guessing you'd probably shave another 5-6 lbs off the front. I didn't want to ruin the nice powder coating so I left them. I plan to use the driver's side bracket to try and attach my torque strap anyway so at least one mount will be used for something. If you're using a motor plate and/or a rack ditching the the motor mount brackets and steering box mount would obviously save a significant amount of weight.

I'd also like to point out to the eagle-eyed folks here that the Flaming River manual steering box you see in the pic recently got the heave-ho. I bought a new 20:1 factory style aluminum one from Mancini at Carlisle this year to replace it. The FR box is cast iron and weighs 19lbs while the factory one is around 9 lbs. I was OK with using it but it's a 16:1 ratio which I don't want. I've had that box for years and have never used it. Maybe in another project.

So in the end going to the QA1 front end and ditching the FR box saved me 28lbs off the front. If I had skipped the FR box to start with it would just be 18lbs.

 

[fullmetaljacket]

Ironically, my weight conscious self never went the route of trimming the pinch weld areas perhaps for the reason of having no access to a reputable welding guy at the time. (Long story) I instead carefully and surgically cut and removed all non essential brackets being that I went with a front motor plate. I trimmed the steering box brackets as well and actually had a much better bead of tig weld button it all up in place of the shoddy factory stick welds.
I had 4 custom titanium K-bolts spun and threaded at Trick Titanium and that was it.
I lost a fair amount of weight, but was always and still am haunted to this day by not doing it all the way like you John or DVW's.
RMCHRGR's tricked out Duster has a little ways to go, but it will be a feather weight contender I am sure.
I guess when I finally find my holy grail 2% Magnesium K-member or A/FX stainless K-member, I'll come back here to boast and toast. LOL.

 

[dvw]

This is mine.
Doug

 

[fullmetaljacket]

By the way, Bondo Bob fabricated my CM steering shaft as part of the aluminum steering jacket assembly for the car. He has mad talent. The joints and welds are art.

 

[fullmetaljacket]

So after a break back to my "BITTER LIME" GTX weight loss program!
When we left off the GTX was down to 3029 LBS and my goal then was 3000 LBS!
At that time I had about 6 front K members laying around from parted out cars.
I decided to take one of the rougher ones and start trimming the clamping flanges with a cutting wheel.
I got about half of it trimmed off and went and had that area seam welded.
Then I went back and trimmed the rest off along with some of the bracing for the motor mounts and steering box.
Then I got the rest seam welded. The result was a weight loss of 12 LBS and now down to 3017 LBS! WOW!
At the same time when I installed the light weight K member I installed non sway bar lower control arms.
That resulted in another weight loss of 3 LBS and now down to 3014 LBS.
During this time I also swapped out some hardware for 2 more LBS and down to 3012!
3000 LBS here we come!
I have attached some before and after pictures of K members with and without the clamping flanges.
MJ

View attachment 1711646

View attachment 1711647

View attachment 1711648

View attachment 1711649

MJ. From what I think my eyes are seeing is that you cut and trimmed away at the underbelly of the K by making the scalloped cavities much bigger. Is this correct? Most importantly, is it strong?

 

[rmchrgr]

MJ. From what I think my eyes are seeing is that you cut and trimmed away at the underbelly of the K by making the scalloped cavities much bigger. Is this correct? Most importantly, is it strong?

Should be fine. Yes, the K frame is a stressed member of the chassis but the outer frame rails flex more. I don't think the K member would flex at all if you have a motor plate and/or a mid plate since the engine is essentially tied into the frame.

DVW does not have the gusset plate in his and that car does 3 ft. wheelstands on every pass. Bondo Bob's version does not have it nor does the QA1 K and that one is made for street cars.

If you drive the car into a 2 foot deep pothole stuff is gonna get bent whether the gusset plate is there or not.

 

[fullmetaljacket]

Should be fine. Yes, the K frame is a stressed member of the chassis but the outer frame rails flex more. I don't think the K member would flex at all if you have a motor plate and/or a mid plate since the engine is essentially tied into the frame.

DVW does not have the gusset plate in his and that car does 3 ft. wheelstands on every pass. Bondo Bob's version does not have it nor does the QA1 K and that one is made for street cars.

If you drive the car into a 2 foot deep pothole stuff is gonna get bent whether the gusset plate is there or not.

Duly noted.
Like you mentioned, a front and or mid motor plate kind of makes itself into a second elevated K member, thus arguably creating a boxed cage upfront. The car does have a front motor plate, so the dynamic stress points are now transferred to the longitude frames rails as you said, but the K underneath is still carrying the overall torsional twists and weight, not mentioning some of the steering components.
Though my wheel stands are more like quick 8" high wheel skips rather than gracefully carrying for a distance, I do think of the K as the weak point where as if the wheel stands were more stretched out like smooth airliner landings, I wouldn't worry about a trimmed K as much.
Obviously carrying them for a distance and landing is different from car to car and driver to driver. I don't think even a high standing Bronco car will do damage to the K, oil pan and other stuff if the landings are soft after a graceful segmented arch.

I'll eat my own words because an exotic K from back in the day is probably more prone to collapsing than a modified steel member nowadays. Chrysler had an issue with the lightweight stainless K's back in '65 because of wheel stands and the subsequent violent landings. I would suspect that if the cars weren't as violent and the rear tire technology was up to par, those stainless units (though only about a dozen or so were stamped) would still be around today. I've seen one or two for sale that were battered like they were in a war zone.

The Magnesium units which still bare the burden of proof to ever have existed at all, have no record, street or track.

Meanwhile back at the ranch, dealing more with moon pot holes than a smooth track these days is probably more destructive.

 

[Mopar John]

MJ. From what I think my eyes are seeing is that you cut and trimmed away at the underbelly of the K by making the scalloped cavities much bigger. Is this correct? Most importantly, is it strong?

fullmetaljacket,
I did cut as much as I felt comfortable with on the bottom side cavities!
It is strong as this was done in 2005 and hundreds of runs ago!
The GTX runs 9.45 - 9.55 1/4 and 5.99 - 6.10 1/8 depending on the weather.
Attached is the latest good picture of a typical launch.
MJ

 

[dvw]

From what I was told the magnesium units were never used for competition. They do exist. I've held one in my hands. As I remember it weighs about 7lbs.
Doug

 

[fullmetaljacket]

fullmetaljacket,
I did cut as much as I felt comfortable with on the bottom side cavities!
It is strong as this was done in 2005 and hundreds of runs ago!
The GTX runs 9.45 - 9.55 1/4 and 5.99 - 6.10 1/8 depending on the weather.
Attached is the latest good picture of a typical launch.
MJ

View attachment 1711984

MJ. That there looks to be an even Steven launch and believe you would not have any issues. Car is fabulous. You're knocking on the doors of sub 3000 lbs. Question is: will it be not enough. LOL.

 

[fullmetaljacket]

From what I was told the magnesium units were never used for competition. They do exist. I've held one in my hands. As I remember it weighs about 7lbs.
Doug

Yes D.
Now I remember you mentioning that the Mags did indeed exist. Folklore as it sounded, somewhere I also read that these ghost units were delicate and were deemed unusable. Secret back door Detroit truth or dare operations. I love it.

RMCHRGR and I were eyeing a certain ultra lightweight car at Carlisle that was presumedly wearing one of those mag units underneath.

 

[fullmetaljacket]

Since we're now loitering in the K member section, here's a little something that will be replaced soon.................

 

[fullmetaljacket]

...................with this. It may be a few ounces or perhaps more, but I'll take it.

 

[fullmetaljacket]

Let's refresh this thread by saying that "Light is Might" folks. Everything will work less and last more if the weight is the right stuff.

Our planet Earth itself is lightweight in the universe. Just think of how it floats in mid-nothingness. LOL.

 

[Mopar John]

Since it has gone quiet here I decided to continue on with my weight loss program!
When we left off the weight was down to 3012 LBS.
So I bought a new set of wheels and front tires.
The front wheels and tires went from 44 LBS down to 36 LBS and 3004 total!
Those old Crager's and A78 X 15 Volkswagon tires were HEAVY!
The rear wheels was another 4 LBS and I made it 3,000 LBS total!
I made a notation here that the GTX ran a 9.81!
So by switching to a 904 and losing a bunch of weight I went from 10.30's down to 9.81!
I have attached a couple of pictures showing the difference in the wheels and front tires.
MJ

 

[fullmetaljacket]

Since it has gone quiet here I decided to continue on with my weight loss program!
When we left off the weight was down to 3012 LBS.
So I bought a new set of wheels and front tires.
The front wheels and tires went from 44 LBS down to 36 LBS and 3004 total!
Those old Crager's and A78 X 15 Volkswagon tires were HEAVY!
The rear wheels was another 4 LBS and I made it 3,000 LBS total!
I made a notation here that the GTX ran a 9.81!
So by switching to a 904 and losing a bunch of weight I went from 10.30's down to 9.81!
I have attached a couple of pictures showing the difference in the wheels and front tires.
MJ

View attachment 1715246

View attachment 1715249

MJ.

Your weight loss program is paying dividends for sure. That Yacht is an optic bag of tricks to even us Moparites.
Unless it was wearing a bunch of fiberglass panels, I would be thinking that it 's hinging on at least 3400 Lbs. I love it.

I studied your front wheels and noticed that they look like the Cragar stars or something like that. I always thought that those were light, so I guess not. Tire weight itself can vary extremely from one type of tire to another. The lightest that I have seen and run are the Moroso DS2 drags, but their safety and survival is questionable on these mean streets. Rotating weight is a MFKER.
3000 lbs is amazingly trim for that wheelbase and carcass.
The '65 altar boy is literally only a few Lbs lighter than yours and obviously not as innocent or innocent looking. For that, I guess it needs to recite quite a few HELL Mary's. LOL.

 

[fullmetaljacket]

A quiet thread may not necessarily mean dead, just that some may be scheming and creating new things and new content. LOL..