|
Re: K frame strength
[Re: feets]
#1900799
08/28/15 12:39 AM
08/28/15 12:39 AM
|
Joined: Dec 2010
Posts: 12,375
SoCal
MuuMuu101
I got lucky at Woodward!
|
I got lucky at Woodward!
Joined: Dec 2010
Posts: 12,375
SoCal
|
Goody, I have a couple tons of bar stock and heavy flat stock at home. It wouldn't be hard to put together a rig like your model. That was what I had in mind.
Load testing for the engine weight could be done using an inverted stand. Simple hydraulics could apply the load measured using my proving ring. I have the general Dynamics calibration sheet on the ring that defines loads to 5500 lbs in 50 lb increments. The proper rig would allow testing deflection in heavy cornering due to engine weight as well.
My other gauges and instruments could measure deflection down to .0001" in multiple places.
In my opinion, some tests should demonstrate the strength of the K frame separate from the chassis. Any deflection would show additional load placed on the chassis.
The K should stand on it's own as much as possible and not rely on a relatively flexible chassis for support.
Thoughts?
Ya'll need to do this. And get it in a magazine. With as many K frames as you can get your hands on. I'm up for it if they are. I'm down. Unfortunately I don't have a CAD program at home, but I can offer hand drawings and calcs.
|
|
|
Re: K frame strength
[Re: Uhcoog1]
#1900889
08/28/15 03:47 AM
08/28/15 03:47 AM
|
Joined: Aug 2013
Posts: 106
Central IL
Trojmn
member
|
member
Joined: Aug 2013
Posts: 106
Central IL
|
My current line of belief:
-tire compound matters most
-tire temperature matters second
-tire size matters last
So sure, wider is better, but only if you get the first 2 right.
I also think R compound tires may 'buck the trend' a bit past a certain point. Whereas 200tw tires hold the rule a bit better.
right on! a narrower hot tire is almost always better than a [censored] cold wide tire. I would add: generally maximize the wheel width then the tire, to actually put the tire against the ground. /thread divert
|
|
|
Re: K frame strength
[Re: feets]
#1901236
08/28/15 06:17 PM
08/28/15 06:17 PM
|
Joined: Jan 2003
Posts: 751
Saint Peters, MO
Brian
super stock
|
super stock
Joined: Jan 2003
Posts: 751
Saint Peters, MO
|
Kevin,
What stock and modified K's are you looking to test, (A's, B's or E's)?
1971 6.1 Gen III Hemi Duster
|
|
|
Re: K frame strength
[Re: feets]
#1901361
08/28/15 08:56 PM
08/28/15 08:56 PM
|
Joined: Jan 2003
Posts: 28,067
Irving, TX
feets
OP
Senior Management
|
OP
Senior Management
Joined: Jan 2003
Posts: 28,067
Irving, TX
|
I had B bodies in mind since that's the K-frame I have at home.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
|
|
|
Re: K frame strength
[Re: XVracing]
#1910926
09/12/15 02:18 AM
09/12/15 02:18 AM
|
Joined: Dec 2003
Posts: 22,695
Bitopia
jcc
If you can't dazzle em with diamonds..
|
If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,695
Bitopia
|
A K member is a component of the chassis.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
|
|
|
Re: K frame strength
[Re: XVracing]
#1911038
09/12/15 11:57 AM
09/12/15 11:57 AM
|
Joined: Jan 2003
Posts: 28,067
Irving, TX
feets
OP
Senior Management
|
OP
Senior Management
Joined: Jan 2003
Posts: 28,067
Irving, TX
|
JCC, So what's being tested here, how much rigidity the K frame adds to the chassis?
CR That's part of it. We all know the chassis is floppy. The K frame adds appreciable rigidity by connecting the front rails together. It also has to take the loads from the engine, steering, and suspension. There are some parts available that do not appear to have the same rigidity as the stock piece. If that's true, guys are spending good money on weaker parts in exchange for a little extra clearance or bit of nifty factor. Do an eyeball test of these two pieces:   There have also been a few aftermarket members that do not fit and some that have failed structurally. When buying into these things, what are you really getting? I imagine you believe in your products. After all, they're your products. The other manufacturers likely feel the same way. I don't think anyone has done a direct comparison between the products available.
We are brothers and sisters doing time on the planet for better or worse. I'll take the better, if you don't mind.
- Stu Harmon
|
|
|
Re: K frame strength
[Re: XVracing]
#1911064
09/12/15 01:11 PM
09/12/15 01:11 PM
|
Joined: Dec 2003
Posts: 22,695
Bitopia
jcc
If you can't dazzle em with diamonds..
|
If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,695
Bitopia
|
JCC, So what's being tested here, how much rigidity the K frame adds to the chassis?
CR I have said this before, most of us will agree on the numerical data, its our own interpretations of the data that will foster many more threads.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
|
|
|
Re: K frame strength
[Re: feets]
#1911137
09/12/15 04:19 PM
09/12/15 04:19 PM
|
Joined: Feb 2011
Posts: 4,302
Nebraska
72Swinger
master
|
master
Joined: Feb 2011
Posts: 4,302
Nebraska
|
The torsional test would validate a K members integrity IMO. That is really the only place it could or couldn't make a difference. But I also can see where people who have had the LCA pivots broken or wallered out would think that THAT is the improvement.
Mopar to the bone!!!
|
|
|
Re: K frame strength
[Re: feets]
#1911272
09/12/15 09:02 PM
09/12/15 09:02 PM
|
Joined: Sep 2014
Posts: 37
NY
XVracing
member
|
member
Joined: Sep 2014
Posts: 37
NY
|
On track test are really not valid because there are too many variables.
Driver being of the largest variables, chassis setup being another huge one.
I have said this numerous times that the data is only as good as the person reading it. There was another post a while back of a person offering free time on a 4 post shaker rig for testing, nobody took it. Namely because number one, you have to come up with a test that means something, and two you have to be to interpret the data you got from said test.
BTW the K does a lot more than hold the frame rails straight. Again, some things you can't measure statically. It has to support the lower control arms as pointed out, and also support the engine as well as counteract the torque.
Just because the aftermarket K frame doesn't look as big as the factory, doesn't mean it's as strong, or stronger...
A Torsional Rigidity test can be done with the K installed or not, the better the rails are without the K installed, the better it will be with it installed.
My suggestion would be to twist the K members out of the car.
CR
|
|
|
Re: K frame strength
[Re: XVracing]
#1911280
09/12/15 09:26 PM
09/12/15 09:26 PM
|
Joined: Dec 2010
Posts: 12,375
SoCal
MuuMuu101
I got lucky at Woodward!
|
I got lucky at Woodward!
Joined: Dec 2010
Posts: 12,375
SoCal
|
On track test are really not valid because there are too many variables.
Driver being of the largest variables, chassis setup being another huge one.
I have said this numerous times that the data is only as good as the person reading it. There was another post a while back of a person offering free time on a 4 post shaker rig for testing, nobody took it. Namely because number one, you have to come up with a test that means something, and two you have to be to interpret the data you got from said test.
BTW the K does a lot more than hold the frame rails straight. Again, some things you can't measure statically. It has to support the lower control arms as pointed out, and also support the engine as well as counteract the torque.
Just because the aftermarket K frame doesn't look as big as the factory, doesn't mean it's as strong, or stronger...
A Torsional Rigidity test can be done with the K installed or not, the better the rails are without the K installed, the better it will be with it installed.
My suggestion would be to twist the K members out of the car.
CR I agree with most of all what you're saying. There isn't without a doubt that it supports the LCA's and deal with the loads inputted by the engine (weight, torque, vibrational loads). Again, those are all difficult to measure and take into consideration. A very simple jig could be built to test how much twist the stock K-member has vs. the aftermarket ones. Fix one side of the K-member, apply a lever arm to the other side to input a torque, and measure the deflection using dial indicators.
|
|
|
Re: K frame strength
[Re: MuuMuu101]
#1911288
09/12/15 09:47 PM
09/12/15 09:47 PM
|
Joined: Sep 2014
Posts: 37
NY
XVracing
member
|
member
Joined: Sep 2014
Posts: 37
NY
|
A very simple jig could be built to test how much twist the stock K-member has vs. the aftermarket ones. Fix one side of the K-member, apply a lever arm to the other side to input a torque, and measure the deflection using dial indicators.
Exactly what I was thinking... Bolt down 3 of the 4 bolts, jack it on the 4th free one with a scale pad under it... CR
|
|
|
Re: K frame strength
[Re: XVracing]
#1911295
09/12/15 10:00 PM
09/12/15 10:00 PM
|
Joined: Dec 2003
Posts: 22,695
Bitopia
jcc
If you can't dazzle em with diamonds..
|
If you can't dazzle em with diamonds..
Joined: Dec 2003
Posts: 22,695
Bitopia
|
What you are bolting it to, depending on how one is doing the bolting, will add false rigidity.
Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
|
|
|
Re: K frame strength
[Re: feets]
#1911307
09/12/15 10:10 PM
09/12/15 10:10 PM
|
Joined: Dec 2014
Posts: 5,754
ohio
ruderunner
master
|
master
Joined: Dec 2014
Posts: 5,754
ohio
|
I've been thinking about this. I don't think the test you propose has much to do with the real world. The K is basically like a sheet of plywood and they all will flex a lot. What's missing is the inner fenders and firewall which combined make a large box that resists flex or twist.
What the K really does is prevent paralelograming of the front subframe. Here is where the stock K looks to be much better than most aftermarket units. Look at all the triangulation in the stocker vs aftermarket.
Just my take on it...
Angry white pureblood male
|
|
|
Re: K frame strength
[Re: feets]
#1911369
09/12/15 11:48 PM
09/12/15 11:48 PM
|
Joined: Sep 2007
Posts: 14,889
up yours
Supercuda
About to go away
|
About to go away
Joined: Sep 2007
Posts: 14,889
up yours
|
One thing the stock K member does better than any aftermarket one I've seen is support the LCA inner mounting point. Some of the aftermarket ones are nothing more than a foot of box tubing with some tabs cantilevered off it for the LCA mount. HDK comes to mind, especially in regards to not having a clue what the word parallelograming means. http://i160.photobucket.com/albums/t164/Freaks-Photos/70%20Dart/K-in-car.jpg
They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.
|
|
|
Re: K frame strength
[Re: feets]
#1911378
09/13/15 12:00 AM
09/13/15 12:00 AM
|
Joined: Jan 2010
Posts: 667
Los Osos, Ca
CKessel
mopar
|
mopar
Joined: Jan 2010
Posts: 667
Los Osos, Ca
|
Chris, thank you for chiming in on this with Peter, Feets, JCC etc. You and Peter especially since you have been exposed to the test rigs and stuff with current and former employers and can weed through the feces and shinola. I'm interested in this as I'm not a believer of the A/M units as there is not enough cycle time, miles, crappy roads, Dukes Of Hazard imitations etc on them to prove they are worthy of purchasing and using. I know that eventually we will have no choice when nothing else available to us[ hint, hint for someone to make]. I've been working on the 70 k unit that will be going into my 65 and am interested in where worthwhile improvements can be made as I plan to autocross, road course, drag etc the car. Two of the things I've done are: add in 108 spot/plug welds around the k perimeter compared to 37 factory spot welds, box in the strut rod mount area on the backside of the k instead of just using the 2 attachment spots from Ma Mopar. Salivating on this subject fellas!!!!! Keep at it.
Carl Kessel
|
|
|
Re: K frame strength
[Re: feets]
#1911454
09/13/15 02:05 AM
09/13/15 02:05 AM
|
Joined: Feb 2011
Posts: 4,302
Nebraska
72Swinger
master
|
master
Joined: Feb 2011
Posts: 4,302
Nebraska
|
If they braced the mounts of the K back the crossmember and went with a factory lower control/strut rod arrangement and kept the torsion bars but still use a rack, I'd like it more.
Mopar to the bone!!!
|
|
|
|
|
