Help me choose a suspension setup

Norm Peterson

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If you still think that is no change and the braces make no difference, you are definitely the one with the illusion and imagination going on....
Tell you what . . . if the weather over the next few days co-operates, maybe I'll try run a few jacking tests of my own. With real measurements instead of yes-no 'eyeballing'.


Norm
 

Pentalab

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In this no-brace case the other front tire is already very close to being lifted clear of the ground.

Norm

Whoa. Are you talking about say placing the floor jack just aft of the RF wheel, then with braces added to the mix..... the LF comes off the ground ?

I was referring to jack just aft of RF.. then with braces added, the RR also comes off the ground.

Way back a few yrs, somebody on S197 posted a pix, whereby the jack was aft of RF.....and RR and LF were also off the ground ! leaving only the LR in contact with the ground. I wish I knew where to look for that pix. I believe they had a full roll cage installed as well, (including through the A pillar area)..which may well explain the effect. To pull that stunt off, the jacking point would have to be inboard a bit, to get the exact balance point side to side...and front to rear.

On a similar note, can the unibody/chassis be viewed as a '5th spring'..between front and rear suspension ? If so, then the '5th spring' is undamped, which further complicates the entire mess. Checking some old notes that I could dig up here and there, some have said with the SFC's welded into place, the car then felt like either the front sway bar, and /or front springs were on steroids. It wouldn't lean as much in the corners...and that's with no changes to front sway bar settings, or spring rates, or camber adjustments. Bushing compliance, tire deflection, roll center, scrub radius, etc, etc, further makes the total suspension package, a hard concept to grasp. It amounts to a 3D twisting and bending myriad of components. Just when I think I have it figured out, I don't.

................................................................................................................

"There's a bit of an illusion and stuff left to the imagination going on with that demonstration"

I'd call it a damn good demo, truly impressive by most standards. Dunno why the SFC manufacturers, like steeda, KB, BMR, don't use it in their own videos.
 
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JJ427R

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Whoa. Are you talking about say placing the floor jack just aft of the RF wheel, then with braces added to the mix..... the LF comes off the ground ?

I was referring to jack just aft of RF.. then with braces added, the RR also comes off the ground.

I do believe by Norm's response above that is what he was thinking.... this whole thread.... :angry1:

I also meant to say as Pentalab said, jack behind front wheel and the back wheel comes off the ground. If you jack the rear as I stated above it will start lifting the entire side of the car but front wheel does not come off the ground at the same rate because of all the weight on front.
When spring gets here I can do a video of jacking the car to demonstrate this as well....
 
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Pentalab

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I do believe by Norm's response above that is what he was thinking.... this whole thread.... :angry1:

I also meant to say as Pentalab said, jack behind front wheel and the back wheel comes off the ground. If you jack the rear as I stated above it will start lifting the entire side of the car but front wheel does not come off the ground at the same rate because of all the weight on front.
When spring gets here I can do a video of jacking the car to demonstrate this as well....

Ideally, jack it up at the midpoint, or just a tad forward of the midpoint, then both the front + rear should come off the ground at the same rate. Of course, this will all depend on how much the front / rear is lowered, struts /shocks used / tire diameter's..and whether the extra weight of a blower / HE/ De-gas / IC etc, is part of the extra front end weight. Then how much fuel in the tank, and misc.....'junk in the trunk'.

So any video demo should involve jacking front / center / rear. Then repeat on a car with no SFC's. Then run, don't walk..and install some SFC's. Roush gets 1/2" front drop from their springs..and the other 1/2" front drop from their shortened monotube front struts. (very bottom of roush strut to spring perch is 1/2" shorter than oem).
 

Norm Peterson

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I was referring to jack just aft of RF.. then with braces added, the RR also comes off the ground.
This is exactly what I meant. I think 'other' was left over from editing when if you were jacking the RR the other right side tire is headed toward being lifted. Sorry for the confusion.


On a similar note, can the unibody/chassis be viewed as a '5th spring'..between front and rear suspension ? If so, then the '5th spring' is undamped, which further complicates the entire mess.
Yes, but not completely undamped (IIRC structural damping ranges between about 2% and 5%)


Checking some old notes that I could dig up here and there, some have said with the SFC's welded into place, the car then felt like either the front sway bar, and /or front springs were on steroids. It wouldn't lean as much in the corners...and that's with no changes to front sway bar settings, or spring rates, or camber adjustments. Bushing compliance, tire deflection, roll center, scrub radius, etc, etc, further makes the total suspension package, a hard concept to grasp. It amounts to a 3D twisting and bending myriad of components. Just when I think I have it figured out, I don't.
Old notes and SFCs . . . sounds like Fox days.


"There's a bit of an illusion and stuff left to the imagination going on with that demonstration"

I'd call it a damn good demo, truly impressive by most standards. Dunno why the SFC manufacturers, like steeda, KB, BMR, don't use it in their own videos.
Let me get back to you on this.


Norm
 
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Norm Peterson

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I also meant to say as Pentalab said, jack behind front wheel and the back wheel comes off the ground. If you jack the rear as I stated above it will start lifting the entire side of the car but front wheel does not come off the ground at the same rate because of all the weight on front.
When spring gets here I can do a video of jacking the car to demonstrate this as well....
I should have measurements by then.

Question - are you always jacking at Ford's OE jack points, even after installing the bracing? Or now that you've installed the bracing have you moved your jack point slightly to take better advantage of the new bracing?


Whoa. Are you talking about say placing the floor jack just aft of the RF wheel, then with braces added to the mix..... the LF comes off the ground ?
I do believe by Norm's response above that is what he was thinking.... this whole thread....
I think I've put your comment against the correct part of Pentalab's post . . . see the first part of post#105 because I'm not typing it twice . . . you're way too ready & willing to find fault here.


Norm
 

JJ427R

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As Pentalab said after installing jacking rails I now jack on the jack rails at about mid point of the car, or a bit forward of that, to lift the entire side of the car.

All the names and terms you've called me in this thread (as Pentalab pointed out above), and you wonder why I'm willing to find fault quickly....
I've tried to this point be nothing but civil in my commentary, not derogatory as you and some others have been...

Last thing I'll say is that me, as a novice driver and not a pro, in not a fully track prepped car and still a street car, that I absolutely could, and did, cut 2 seconds in my lap time from adding these to my car, and at this point you can do all the measuring you want, and give me all the data you want, I really don't care, it makes no difference to me, you are only trying to prove something to yourself.... Now I am done with this thread....
 

Norm Peterson

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As Pentalab said after installing jacking rails I now jack on the jack rails at about mid point of the car, or a bit forward of that, to lift the entire side of the car.
So of course both wheels are going to come up.

Question - was your first lift with the bracing only a few inches forward of Ford's aft jack point or a few inches aft of Ford's forward jack point?

Is it fair to assume that you did not jack the car up at those locations before the jacking rails were added? This could be very important.


All the names and terms you've called me in this thread (as Pentalab pointed out above), and you wonder why I'm willing to find fault quickly....
I've tried to this point be nothing but civil in my commentary, not derogatory as you and some others have been...
Disclaimers aside, having opinions and explanations on a topic that I spent decades performing on a profession at a level repeatedly dissed as unjustified
I just don't like unjustified opinions of a product based on peoples thoughts….
was completely uncalled for - even if the wording used probably would pass a sniff test for civility.


Last thing I'll say is that me, as a novice driver and not a pro, in not a fully track prepped car and still a street car, that I absolutely could, and did, cut 2 seconds in my lap time from adding these to my car,
We've been through this. Over and over. Cutting those 2 seconds from your lap times after adding the bracing was never in question. There's no dispute here, certainly not one involving me.


Norm
 
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Norm Peterson

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Pentalab just nailed it. After Matrix brace and jacking rails, I can jack from right in front of rear wheel and it lifts the entire side of the car off the ground, prior no way. How do you explain this with your no flex in the chassis theory?
You are rocking the chassis about a diagonal axis running from the opposite-side rear corner through the same-side front corner. Don't forget that all four corners are flexibly supported because they're all suspended on springs.

This is one of the things I intend to measure . . . at all four corners.


Norm
 

Pentalab

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I have never tried jacking the car up, dead center (without jacking rails / sfc's). That would make me cringe. Ford sez...don't attempt it. I can envision something taking a 'permanent set'..( eng talk for 'bent'). jjr427R and myself both have the added weight of the Roush M90 blower / IC / HE / IC pump / 1 gal de-gas / aluminum intake manifold...+ aprx another 16 lbs of IC / HE loop coolant...I believe aprx 90-100 lbs. In my case, I typ have the trunk packed full of junk, and close to a full tank of gas.

On a side note, one fellow slid off the road in the wet, and put the pass side door smack into a utility pole. He had a 2008 GT, with BMR sfc's welded into place. They thought the sfc's on pass side, may well have been a contributing factor in saving the passenger's life. So there is also the potential of added safety.
Another fellow on the Roush forum (in curb lane) had a woman (in center lane)...blathering on her cell phone..decide to change lanes...on a left hand sweeper. She forces him off the road....into a lamp standard. 2007 stang GT hits the light pole... right where the pass side strut mount is located. His experienced body shop repair guy sez if he didn't have the front STB installed, the car would have been a right off. As is, it was repairable. Another fellow was rear ended badly, the rear bumper ended up just a foot aft of driver's head rest. Thank god, he had no rear passengers. The next vehicle had a rear mount X brace installed. So the various bracing's may have other benefits besides their intended purpose.
 

JJ427R

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Question - was your first lift with the bracing only a few inches forward of Ford's aft jack point or a few inches aft of Ford's forward jack point?
Don't remember for sure but I think it was about straight down from side mirror or door hinges.

Is it fair to assume that you did not jack the car up at those locations before the jacking rails were added? This could be very important.
That would be correct, always factory points prior.
 

Juice

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I place my jack just in front of the door handle, put a piece of 2x4 just behind the pinchweld and lift one side on the 07 mustang. Been doing this for years without any issues.
Wife's car, Grand marquis, same deal. The sweet spot is just in front of tbe B pillar.
I looked up the X brace w/rear seat delete--too much $$$ for what is in rhe kit. Not paying $1100 for that since I would rather do a roll bar & 5pt harness.
 

Pentalab

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I place my jack just in front of the door handle, put a piece of 2x4 just behind the pinchweld and lift one side on the 07 mustang. Been doing this for years without any issues.
Wife's car, Grand marquis, same deal. The sweet spot is just in front of the B pillar.
I looked up the X brace w/rear seat delete--too much $$$ for what is in the kit. Not paying $1100 for that since I would rather do a roll bar & 5pt harness.

Forget the FRPP / Boss 302 version, too much $$, and doesn't tie into rear shock mounts. Here's what I have coming. https://www.steeda.com/steeda-mustang-rear-chassis-xbrace-555-5093.html 2 x good pix here.

Also carried by AM. https://www.americanmuscle.com/steeda-xbrace-0514coupe.html Loads of pix too.
I need the rear seats..... for misc junk I toss in there.

Never thought of the 2x4 trick. I woulda thought it might slide inboard, but apparently not.
 

Juice

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Thanks, I do like the price of that Steeda x.

I just wonder if it would be of benefit if I install the Watson racing 4pt cage.
 

Norm Peterson

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Never thought of the 2x4 trick. I woulda thought it might slide inboard, but apparently not.
Hadn't occurred to me either, until setting up a test sequence to measure what's going on with a variety of slightly different lifting positions.

I might add something to improve grip or otherwise more positively locate the 2x4 against sliding inward.


Norm
 

Juice

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Never had the 2x4 move on me. And the main reason for using a piece of wood was just to protect the finish under there.
 

Norm Peterson

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On a side note, one fellow slid off the road in the wet, and put the pass side door smack into a utility pole. He had a 2008 GT, with BMR sfc's welded into place. They thought the sfc's on pass side, may well have been a contributing factor in saving the passenger's life. So there is also the potential of added safety.
Another fellow on the Roush forum (in curb lane) had a woman (in center lane)...blathering on her cell phone..decide to change lanes...on a left hand sweeper. She forces him off the road....into a lamp standard. 2007 stang GT hits the light pole... right where the pass side strut mount is located. His experienced body shop repair guy sez if he didn't have the front STB installed, the car would have been a right off. As is, it was repairable. Another fellow was rear ended badly, the rear bumper ended up just a foot aft of driver's head rest. Thank god, he had no rear passengers. The next vehicle had a rear mount X brace installed. So the various bracing's may have other benefits besides their intended purpose.
Not just possible - I'll take it further to "highly likely". Those loads are being applied in directions that these various bracings are most effective at resisting, and the added structural strength is directly improving passenger cell integrity - particularly from the undercar bracing.


Norm
 

Norm Peterson

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So I made a few measurements today. Here's what happens at each corner as the RR is jacked up at that jack point (about 23" forward of the rear axle line). The LF goes down, all other corners go up. Tire sidewall heights reflect less load on the RR, RF, and LR, and more load on the LF, which is consistent with the chassis displacements. I checked at 2", 3", 4", 4.56" (when the RR lifted), and 6.75" (when the RF also lifted).

Chassis displacement & Tire Compliace Plots when the car is jacked up at the RR jack point.jpg


FWIW, my driveway is level within about 1/8" over the track width of an S197. The springs on my '08 GT are somewhat stiffer than OE (260/220) and there's a bit more bar stiffness as well. I suppose it's possible that softer-suspended Mustangs wouldn't lift the RF, but I'm afraid there isn't any easy way for me to check that.


Norm
 

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