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Are these alignment specs unstreatable?

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304-dude View Drop Down
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    Posted: Jul/22/2017 at 7:56am
Now that I am in the running to do the big change...

Here my specs I plan to run with once things are set into place, after all I will have a lot built around Mustang steering.

SVT Rims 17x9 with P295/45 (Front) P315/45 (Rear)

Toe in 1/16" (Some run 0)
Caster 7° (Shelby GT500)
Camber -2° (SVT SCCA track)

The above are a general mix of Mustang performance preferences for auto cross.

My main concern is 7° caster, I dont think i have ever driven with that much.


71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 343sharpstick Quote  Post ReplyReply Direct Link To This Post Posted: Jul/22/2017 at 10:34am
That's close to what I have now. I like it.
I have only 1.5 deg. caster camber, to try and save tires. I also have a more aggressive camber curve, so I'll see how things go.
I feel like I could even go with more caster, but I've yet to try it.

Edited by 343sharpstick - Jul/26/2017 at 12:43pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/22/2017 at 11:15am
Originally posted by 343sharpstick 343sharpstick wrote:

That's close to what I have now. I like it.
I have only 1.5 deg. caster, to try and save tires. I also have a more aggressive camber curve, so I'll see how things go.
I feel like I could even go with more caster, but I've yet to try it.


Ah, though 1.5 degrees caster is a bit light compared to 7, but I guess with big tires both caster and camber can be offset by big tires.

I was thinking of pushing -5 degrees camber but that won't do well for daily driving.

Thanks!
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 73Gremlin401 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/22/2017 at 11:29am
Originally posted by 304-dude 304-dude wrote:

Originally posted by 343sharpstick 343sharpstick wrote:

That's close to what I have now. I like it.
I have only 1.5 deg. caster, to try and save tires. I also have a more aggressive camber curve, so I'll see how things go.
I feel like I could even go with more caster, but I've yet to try it.


Ah, though 1.5 degrees caster is a bit light compared to 7, but I guess with big tires both caster and camber can be offset by big tires.

I was thinking of pushing -5 degrees camber but that won't do well for daily driving.

Thanks!


Unlike the old days, massive amounts of negative camber are no longer needed to make a performance tire work well.  .5 - 1 degree of negative camber is gracious plenty for most applications.  With regard to the positive caster, yes, more can help, but it also puts a huge strain on the power steering pump (or, if you have manual steering, your arms). 

With AMC stock lower control arms, any more caster than 2 degrees puts a lot of strain on the pivot bushing and the arm itself.  I do run up to 2.5 degrees of positive caster in my Gremlin for track and autocross use, but I look at the lower control arm regularly, and consider it to be a wear item that has a finite life-span, even with reinforcement.   I also had to push the lower corner of the front fender out about 1" to clear the tires. I run 245/50-16 all around.  AMC did this on Spirit and Concord, I use 83 Spirit front fender spreader bars (the steel bar than runs from the frame rail out to the lower leading edge of the fender).  the earlier Gremlin bars are about 2" shorter. 
73 Gremlin 401/5-spd.
77 Matador 360/727.
80 Concord Limited 4dr. 258/904


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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/22/2017 at 12:32pm
Originally posted by 73Gremlin401 73Gremlin401 wrote:


Originally posted by 304-dude 304-dude wrote:

Originally posted by 343sharpstick 343sharpstick wrote:

That's close to what I have now. I like it.
I have only 1.5 deg. caster, to try and save tires. I also have a more aggressive camber curve, so I'll see how things go.
I feel like I could even go with more caster, but I've yet to try it.


Ah, though 1.5 degrees caster is a bit light compared to 7, but I guess with big tires both caster and camber can be offset by big tires.

I was thinking of pushing -5 degrees camber but that won't do well for daily driving.

Thanks!


Unlike the old days, massive amounts of negative camber are no longer needed to make a performance tire work well.  .5 - 1 degree of negative camber is gracious plenty for most applications.  With regard to the positive caster, yes, more can help, but it also puts a huge strain on the power steering pump (or, if you have manual steering, your arms). 

With AMC stock lower control arms, any more caster than 2 degrees puts a lot of strain on the pivot bushing and the arm itself.  I do run up to 2.5 degrees of positive caster in my Gremlin for track and autocross use, but I look at the lower control arm regularly, and consider it to be a wear item that has a finite life-span, even with reinforcement.   I also had to push the lower corner of the front fender out about 1" to clear the tires. I run 245/50-16 all around.  AMC did this on Spirit and Concord, I use 83 Spirit front fender spreader bars (the steel bar than runs from the frame rail out to the lower leading edge of the fender).  the earlier Gremlin bars are about 2" shorter. 


Yes, I do understand what you have stated. So it seems today's wide tires can make up for camber. I should have explained that I am modernising my suspension to allow my settings without setting adjustments out to the max as with a stock suspension.

343sharpstick knows some of my mods and has introduced his own take with his trunnion replacement kit.

I have also incorporated a Mustang rack and pinion, so some assisted power will compensate for more positive castor.

I have changed, or will be changing suspension tower location soon, to place positive castor as a default point with strut rod centered in its adjustment. Thus modernising the older stock setup.

Plus I have extended both control arms location 1" out towards the fender. Since I plan on flaring the wheel openings and are using Ford SVT rim with an offset, I fit a wider tire.

In a way I was expecting more mebers with a CF suspension, who auto cross street driven cars, to chime in on how much they allow for daily driving.



71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 73Gremlin401 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/22/2017 at 1:37pm
Originally posted by 304-dude 304-dude wrote:

[QUOTE=73Gremlin401]
[QUOTE=304-dude] [QUOTE=343sharpstick]

I have changed, or will be changing suspension tower location soon, to place positive castor as a default point with strut rod centered in its adjustment. Thus modernising the older stock setup.

Plus I have extended both control arms location 1" out towards the fender. Since I plan on flaring the wheel openings and are using Ford SVT rim with an offset, I fit a wider tire.

In a way I was expecting more members with a CF suspension, who auto cross street driven cars, to chime in on how much they allow for daily driving.



I like your idea of re-locating the suspension tower, the way AMC fabricated the side walls there's no reason it can't be done fairly cleanly and still look 'stock' to the casual observer.  I'd love to see some before and after pics of the process. 

I wish I was one of the ones with a CF setup to tell you how it works on track!!  I love their kits, and unfortunately for me, it all appeared on the market shortly after I did a coil-over conversion on mine.  Timing is everything....
73 Gremlin 401/5-spd.
77 Matador 360/727.
80 Concord Limited 4dr. 258/904


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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/22/2017 at 2:29pm
Originally posted by 73Gremlin401 73Gremlin401 wrote:


Originally posted by 304-dude 304-dude wrote:

[QUOTE=73Gremlin401]
[QUOTE=304-dude] [QUOTE=343sharpstick]

I have changed, or will be changing suspension tower location soon, to place positive castor as a default point with strut rod centered in its adjustment. Thus modernising the older stock setup.

Plus I have extended both control arms location 1" out towards the fender. Since I plan on flaring the wheel openings and are using Ford SVT rim with an offset, I fit a wider tire.

In a way I was expecting more members with a CF suspension, who auto cross street driven cars, to chime in on how much they allow for daily driving.



I like your idea of re-locating the suspension tower, the way AMC fabricated the side walls there's no reason it can't be done fairly cleanly and still look 'stock' to the casual observer.  I'd love to see some before and after pics of the process. 

I wish I was one of the ones with a CF setup to tell you how it works on track!!  I love their kits, and unfortunately for me, it all appeared on the market shortly after I did a coil-over conversion on mine.  Timing is everything....


Well, once I get caught up with one final project, I will be cutting spot welds to remove the lower radiator support (just because), elephant ears, troughs and suspension humps. Will be adding updated pictures to my thread to show the process.

Not sure if you seen the thread and what is required to clear everything to look stock and fit. Relocation of the hood hinge studs and cutting a strip on the firewall side of the opening. Plus cutting a seem, for re bending the upper portion at a wider angle at the top of the tower, to angle the bottom, as to shift the upper arm mounting holes 1 inch closer to the cut mounting flanges (1 on each side) and weld in place. I have not covered the hump mods completely as they are almost ready for bending and welding.

http://theamcforum.com/forum/topic53345_post478885.html#478885
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 73Gremlin401 Quote  Post ReplyReply Direct Link To This Post Posted: Jul/22/2017 at 3:21pm
[QUOTE] Well, once I get caught up with one final project, I will be cutting spot welds to remove the lower radiator support (just because), elephant ears, troughs and suspension humps. Will be adding updated pictures to my thread to show the process.

Not sure if you seen the thread and what is required to clear everything to look stock and fit. Relocation of the hood hinge studs and cutting a strip on the firewall side of the opening. Plus cutting a seem, for re bending the upper portion at a wider angle at the top of the tower, to angle the bottom, as to shift the upper arm mounting holes 1 inch closer to the cut mounting flanges (1 on each side) and weld in place. I have not covered the hump mods completely as they are almost ready for bending and welding.

http://theamcforum.com/forum/topic53345_post478885.html#478885
[QUOTE]

Holy Crap you are fearless.  (and I mean that in an absolutely complimentary way) I like how you are understanding of what engineering AMC put in, and did not put in, to the suspension architecture, and how you are cleanly adapting the Ford rack and uprights.  nice work.
73 Gremlin 401/5-spd.
77 Matador 360/727.
80 Concord Limited 4dr. 258/904


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Post Options Post Options   Thanks (1) Thanks(1)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/22/2017 at 4:18pm
Originally posted by 73Gremlin401 73Gremlin401 wrote:


[QUOTE] Well, once I get caught up with one final project, I will be cutting
spot welds to remove the lower radiator support (just because), elephant
ears, troughs and suspension humps. Will be adding updated pictures to
my thread to show the process.

Not sure if you seen the thread
and what is required to clear everything to look stock and fit.
Relocation of the hood hinge studs and cutting a strip on the firewall
side of the opening. Plus cutting a seem, for re bending the upper
portion at a wider angle at the top of the tower, to angle the bottom,
as to shift the upper arm mounting holes 1 inch closer to the cut
mounting flanges (1 on each side) and weld in place. I have not covered
the hump mods completely as they are almost ready for bending and
welding.

http://theamcforum.com/forum/topic53345_post478885.html#478885
[QUOTE]

Holy Crap you are fearless.  (and I mean that in an absolutely complimentary way) I like how you are understanding of what engineering AMC put in, and did not put in, to the suspension architecture, and how you are cleanly adapting the Ford rack and uprights.  nice work.





Thanks! I think It is because I started off with parts finding... 3 years and more off and on. While doing so I got info from Farna about the Ford steering arms and slowly found things that needed addressed as I moved along. So I guess blind careful planning. My mind does most of the work while while I sleep so to speak. Once an idea becomes so simple in concept, the implementation can be time consuming to the fact i have limited resources, and must think of ways to go beyond what I think is a limitation. Very little shop experience and never got into any structural stuff like this, and most of all nobody has quite done things the way I have. So anyway, i hope to have a bit more to add, but this weather is not being kind to me. Looks like add long summer.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/23/2017 at 9:21am
After a bit of looking around deeper with the Ford guys, I made an average assessment with the tires and camber setting most are willing to drive on the streets.

My original thought was -2° and now -1° seems to be about where I should be for dual purpose.

So far a handful of guys are pushing +7° castor with Cobra racks. Vettes on the other hand are up to +5° for GS.

Seems that Ford Cobra racks like or can deal with such angle for castor, or the wider wheel tire combo on the GS vette make too much effort on the GM rack. Ford did set Cobra pumps for more flow on GT500 Mustangs, for the added resistance by high rate of camber.

I will allow for the larger castor angle when finalising my suspension setup. This way I don't end up limiting myself if I find it usable on the streets.

Until I am able to road test further my thoughts on alignment will stand at 0° rake, 1/16" toe in, -1° camber and +7° caster with P295/45R17 tires.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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