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Re: Frame Connectors bad? [Re: moparx] #2675588
07/08/19 03:11 PM
07/08/19 03:11 PM
Joined: Jan 2010
Posts: 1,440
NW Chicago suburban area
Mopar Mitch Offline
pro stock
Mopar Mitch  Offline
pro stock

Joined: Jan 2010
Posts: 1,440
NW Chicago suburban area
I wonder how good the Magnum Force double-tubular SFCs are. Would they be better or as good as the typical 2x2 square SFC?

Despite all the suspension mods I've done (per allowable SCCA E/Street Prepared rules, one thing I've never gotten around to adding are SFCs. In the past, SCCA would not allow SFCs to be welded-in... they could only be bolted-in. Years later, the SCCA later allowed SFCs to be welded in, but only at two-points (front and rear).

I plan to add them sooner or later... after the new engine gets going.. maybe in 2020.

Last edited by Mopar Mitch; 07/08/19 03:17 PM.

Mopar Mitch "Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers! Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
Re: Frame Connectors bad? [Re: Mopar Mitch] #2675660
07/08/19 05:58 PM
07/08/19 05:58 PM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
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Mattax  Offline
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Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Yes SP allowance remains the same - welded at two points.
re: MF- made with tubing. Interesting concepts - potentially should better resist torsional forces.
But still irrelevant for us, as only one additional attachment point is allowed.
I think 2 1x2 rectangular boxes, seam welded together to make a 2x2 would be allowed. How much can from the extra vertical - prob not much.
Probably better to take the roll bar allowances and do as much as possible with that. It could even have a bolted connection to the SFCs - at least the way I read it.

The old DC/MP SFCs are only around 1" tall and 2" wide. That's what'srusting out now in my car now. (saves weight! LOL) Taller would be better and there is room to go taller without hitting the floor or going lower for about 2/3 the distance.

IMO and from what I've observed, the early Barracuda's are relatively stiff, and mid model fastbacks probably nearly as good in that respect. So it all depends what car we're talking about. But yea, for any form of racing SFCs are an advantage. A coworking of mine would place his '67 GTX on jackstands for the week so the quarters wouldn't get wrinkled from racing every weekend. That's what happens when you lift the nose up so the front tires just come off the ground using just springs and pinion snubber (and slicks of course) smile
He's the one that suggested I put the SFCs in - little did I know that they would knock my car into C Prepared.
Still no real regrets.

Re: Frame Connectors bad? [Re: moparx] #2675663
07/08/19 06:03 PM
07/08/19 06:03 PM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
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Mattax  Offline
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Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Originally Posted by moparx
the vertical walls of the connectors add strength, and there is not much to gain going wider than the front and rear subframes [which are around 2" wide]
although i have never done this comparison, it would be interesting to compare a piece of 2x3x1/8 thick [or 12ga-.105 thick] to a piece of 2x2x 3/16 or 1/4 thick.
not much difference in weight [we are looking at commonly available material], but what would be the torsional differences ?
just a reoccurring thought.
beer


Should take a look at the photo sequence in Herb Adams Chassis book. He makes a model of a rail frame and then weights one corner. Then adds a cage like structure and triangulation.

Re: Frame Connectors bad? [Re: Mattax] #2675792
07/08/19 11:35 PM
07/08/19 11:35 PM
Joined: Mar 2003
Posts: 18,677
Fresno, CA
Jim_Lusk Offline
I Live Here
Jim_Lusk  Offline
I Live Here

Joined: Mar 2003
Posts: 18,677
Fresno, CA
Originally Posted by Mattax
Yes SP allowance remains the same - welded at two points.
re: MF- made with tubing. Interesting concepts - potentially should better resist torsional forces.
But still irrelevant for us, as only one additional attachment point is allowed.
I think 2 1x2 rectangular boxes, seam welded together to make a 2x2 would be allowed. How much can from the extra vertical - prob not much.
Probably better to take the roll bar allowances and do as much as possible with that. It could even have a bolted connection to the SFCs - at least the way I read it.

The old DC/MP SFCs are only around 1" tall and 2" wide. That's what'srusting out now in my car now. (saves weight! LOL) Taller would be better and there is room to go taller without hitting the floor or going lower for about 2/3 the distance.

IMO and from what I've observed, the early Barracuda's are relatively stiff, and mid model fastbacks probably nearly as good in that respect. So it all depends what car we're talking about. But yea, for any form of racing SFCs are an advantage. A coworking of mine would place his '67 GTX on jackstands for the week so the quarters wouldn't get wrinkled from racing every weekend. That's what happens when you lift the nose up so the front tires just come off the ground using just springs and pinion snubber (and slicks of course) smile
He's the one that suggested I put the SFCs in - little did I know that they would knock my car into C Prepared.
Still no real regrets.


I don't remember exactly which mod put my son's Barracuda into CP, but we never looked back and his car really wasn't all that competitive (mildly built 383 against full race small blocks with full race suspension) against true CP cars, but there were so few in the local group that he easily won the class for the season. He still drove the car on the street.

Re: Frame Connectors bad? [Re: Jim_Lusk] #2676515
07/11/19 09:23 AM
07/11/19 09:23 AM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
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Mattax  Offline
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Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Yep. That's the way it is. If the regional competition is into the same type prep and skill then that class can be fun and competitive. If you find yourself up against national caliber drivers and national level of preperation its a completely different ball of wax - especially in the non-stock classes! Northern New Jersey we had a good time with CP. In fact several moved into CP based on some small technicality, others on more obvious(?) reasons like the motor build.
http://www.heritech.org/cuda/oldsolo.html

Re: Frame Connectors bad? [Re: Mattax] #2676558
07/11/19 12:39 PM
07/11/19 12:39 PM
Joined: Mar 2003
Posts: 18,677
Fresno, CA
Jim_Lusk Offline
I Live Here
Jim_Lusk  Offline
I Live Here

Joined: Mar 2003
Posts: 18,677
Fresno, CA
His main competition didn't show up to many events, but was fun to watch. A fully race prepped '65 Mustang with a small block that probably had 100 more horsepower than my son's 383 at maybe 500 lbs lighter. If the car ever sees the light of day again it will have a stroked 400 in place of the 383, but I don't know that we'll change much in the suspension besides better shocks and tires.

Re: Frame Connectors bad? [Re: JF_Moparts] #2681083
07/25/19 12:47 AM
07/25/19 12:47 AM
Joined: Aug 2005
Posts: 5,994
Salem
Grizzly Offline
Moparts Proctologist
Grizzly  Offline
Moparts Proctologist

Joined: Aug 2005
Posts: 5,994
Salem
From a Metal Worker/Welders' point of view what Backyard Tony is saying is not entirely wrong. I'm not defending this guy, He has some funny ideas and most of them I question, but, I am willing to listen to Him. If a current Chrysler Engineer or Metalurgist could counter this subject I would really like to hear it.

As I see it, the 4 torque boxes installed at the factory would have taken more time and cost more to install than a simple one-piece frame connector. Period. None of you have commented on how thick the rocker metal is or the fact that it actually is a frame for the car? A T-boned Chrysler Product shows how much strength/metal is in this area. Obviously Chrysler knew what they were doing plus, they were years ahead on Unibody construction than anyone else. I've taken a long hard look at my E-Bodies' torque boxes and I can still slightly justify putting frame connectors that weld to the floor pans and rails, but I will be making my own because I see a flaw in the currently offered design. I want a super-rigid car and know how to get it. smirk

The old rectangular tubing stuff that was bolted or welded in, I would not wast my time with.

At any rate, look under a new Mustang or Challenger to see what they do their Unibodies. Look at the '70 TransAm T/A, AAR race series cars? Works for them obviously. twocents


Mo' Farts

Moderated by "tbagger".
Re: Frame Connectors bad? [Re: Grizzly] #2681602
07/26/19 02:18 PM
07/26/19 02:18 PM
Joined: Dec 2003
Posts: 22,695
Bitopia
J
jcc Offline
If you can't dazzle em with diamonds..
jcc  Offline
If you can't dazzle em with diamonds..
J

Joined: Dec 2003
Posts: 22,695
Bitopia
Originally Posted by Grizzly
From a Metal Worker/Welders' point of view what Backyard Tony is saying is not entirely wrong. I'm not defending this guy, He has some funny ideas and most of them I question, but, I am willing to listen to Him. If a current Chrysler Engineer or Metalurgist could counter this subject I would really like to hear it.

As I see it, the 4 torque boxes installed at the factory would have taken more time and cost more to install than a simple one-piece frame connector. Period. None of you have commented on how thick the rocker metal is or the fact that it actually is a frame for the car? A T-boned Chrysler Product shows how much strength/metal is in this area. Obviously Chrysler knew what they were doing plus, they were years ahead on Unibody construction than anyone else. I've taken a long hard look at my E-Bodies' torque boxes and I can still slightly justify putting frame connectors that weld to the floor pans and rails, but I will be making my own because I see a flaw in the currently offered design. I want a super-rigid car and know how to get it. smirk

The old rectangular tubing stuff that was bolted or welded in, I would not wast my time with.

At any rate, look under a new Mustang or Challenger to see what they do their Unibodies. Look at the '70 TransAm T/A, AAR race series cars? Works for them obviously. twocents


Not clear to me the point you are making above. Care to expound.

I can agree on a couple of your other points, guy is NOT entirely wrong, its his conclusions he makes from those correct points is my issue, such as, making the car too stiff was frowned on by Mopar because it would effectively tear itself apart at the spot welds thinking.. rolleyes


Reality check, that half the population is smarter then 50% of the people and it's a constantly contested fact.
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