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S197 3V Fabman's build; How did we get here? Build Thread

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Fabman

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Have you considered lowering the splitter with a spacer of some sort to try and get some more downforce up front?

Yes, that was one of filips suggestions, I just have fo figure out how to do it cleanly.


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Fabman

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Run a few laps with no wing and see what happens. That’s exactly what I did. But I can almost guarantee he’ll be slower.


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I’m sure it will be the same for me and I didn’t want to waste a session doing it. It’s not like the car is slow, it’s just not going as fast as it could.


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Grant 302

basic and well known psychic
Aside form the adjustments and settings, What are your front tire profile temps and wear telling you?

I just found this from the 302S manual here:
https://performanceparts.ford.com/download/boss302spdfs/2014/Boss 302S owners manual version AV3.pdf

302S front ride height.png

Adjusting alignment (in this order):
  • Set caster. Recommended setting is typically 7° - 7.5°, but equal on both sides
  • Set camber on both sides to -3.0°
    Set toe to 0 degrees or 1/8" total toe out on 30" toe plates
But this is exactly what I'm talking about in the direction of the adjustments. Not far off from what you have, but just more in this direction. In theory, the 302S isn't too far from your setup with the 600/350 f/r springs, rear wing, and the drop front ball joints and the relocated front LCA rear pivot. Really not that different.

This is also the way people should refer to their front 'ride height' instead of fender arch or frame rail measurements, and is independent of tire heights, etc.
 

Fabman

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Aside form the adjustments and settings, What are your front tire profile temps and wear telling you?

I just found this from the 302S manual here:
https://performanceparts.ford.com/download/boss302spdfs/2014/Boss 302S owners manual version AV3.pdf

View attachment 2884


But this is exactly what I'm talking about in the direction of the adjustments. Not far off from what you have, but just more in this direction. In theory, the 302S isn't too far from your setup with the 600/350 f/r springs, rear wing, and the drop front ball joints and the relocated front LCA rear pivot. Really not that different.

This is also the way people should refer to their front 'ride height' instead of fender arch or frame rail measurements, and is independent of tire heights, etc.

Yes that is correct. What actually matters is where the pivot points lie and where the instant centers converge. THAT determines everything, but it flies over most folks heads so it's easier to talk about fender heights etc.
I use the pinch points on the rocker where the jack goes and I have 2 little height gauges that I made. I also have a pointer that I use to locate the inner pivot point and it also reaches inside the wheel to locate the lower ball joint. Once I am satisfied with that I measure the pinch points and that becomes my standard as long as the tire profile doesn't change. I had the lower pivots set just like the Boss302s (I have that info too) and that's how I have been running up until recently. Filip recommended the lower ride height to get the roll center and CG down as well as getting the splitter lower. So that's what I did....and it surprisingly helped although I just know I'm on the bumpers way more than I should be and that bothers me. However, Filip is way more qualified with these cars than I am so I do what he says and figure out why it works after....
 

Fabman

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When I was building stock cars I designed the suspension around the tire height and spindle configuration. I'd use the lowest offset wheel possible to reduce scrub radius and hit the maximum track width spec'd in the rules. Then take your rack pin centers (always 18.250 on stock cars) and the distance from the rack eye to the ball joint became the lower control arm length. Using an .06 to 1 ratio, that would become the upper control arm length. Then I fabricated a fixture so that I can build a repeatable front clip that hit all the numbers/roll center height etc. AND THEN mate it to a chassis, not the other way around. Way easier than taking a car that is already built and then trying to make it conform to racing standards with all it's inherent limitations and design conflicts. I feel like whenever I get something closer to where I think it should be, it makes something else worse, so everything is a compromise, way more of a guessing game than it needs to be IMHO. Its a little like buying a house thats too small and then trying to fit all your furniture in it.
 
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Fabman

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If you look close you can see the fixture holding the front clip at the proper height (by the pivot points) in place for welding before grafting to the chassis. This way I could build several clips at a time and install them on chassis as needed.
This was my personal car and prototype for what followed.
428542_10150994754228535_1853920463_n.jpg

Below are some close ups of a car that I built for a guy in Texas. By this point I was manufacturing my own tubular spindles as pictured here.
165845_10150994698893535_2056183076_n.jpg540796_10150994698763535_2053165924_n.jpg


I'd put them all together and place them on carts and roll them out front while i built other cars. A sort of broke dick assembly line.
(These particular cars went to Utah, Washington and good ole Roseville California)557151_10151014232503535_1625437876_n.jpg1934701_104716183534_5640276_n.jpg
428528_10151014232543535_1757132094_n.jpg
 

Grant 302

basic and well known psychic
Aside form the adjustments and settings, What are your front tire profile temps and wear telling you?

^this was the main part of that post. ;)

The data from your front tires *should* have the answer.

If I put it another way, massive tires shouldn't need *less* spring and bar to control the roll from the added grip available. Running more camber (and maybe the toe) than needed could also start making you change things (like softer spring and bar and roll center) to make the camber setting 'work' for those changes and not the other way around. Hope that makes sense.
 

Fabman

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^this was the main part of that post. ;)

The data from your front tires *should* have the answer.

If I put it another way, massive tires shouldn't need *less* spring and bar to control the roll from the added grip available. Running more camber (and maybe the toe) than needed could also start making you change things (like softer spring and bar and roll center) to make the camber setting 'work' for those changes and not the other way around. Hope that makes sense.
Agreed, that's why I upped the springs. More tire, more bite, more body roll-and I was already almost full stiff on the shocks trying to manage weight transfer, so 600's made sense to me. On track pics show the tire 90* to the track surface under full load and tire wear looks very good. I lowered my pressure 3 psi on the last run and it seemed more consistent throughout the session so I am going to start the next event @ 2 psi less than my usual baseline. Again, while I do carry all the necessary gear to take and log tire temps there is never anyone available and/or capable/willing to do so. I miss having a team, it was so much easier to make changes and log data. It's just my son and I and at this next event at Laguna he is taking driving school in his new s550 50th anniversary Mustang. I won't even have a passenger anymore. :(
I will close up the toe to .125 though I don't see that making all that much of a difference.

I did cut the stops and although I only took off .500, visually there seems to be gobs more travel available. Not sure if they weren't staying pushed up all the way before and showing less available travel or what but even with the 500's lower ride height (letting it sit on the springs a while before I start tweaking ride height) it looks like a ton of travel left. I think I'm going to slam this thing to the ground and see if it likes that.
 

Fabman

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Pleasanton: 1/2 way between Sonoma and Laguna Seca
Aside form the adjustments and settings, What are your front tire profile temps and wear telling you?

I just found this from the 302S manual here:
https://performanceparts.ford.com/download/boss302spdfs/2014/Boss 302S owners manual version AV3.pdf

View attachment 2884


But this is exactly what I'm talking about in the direction of the adjustments. Not far off from what you have, but just more in this direction. In theory, the 302S isn't too far from your setup with the 600/350 f/r springs, rear wing, and the drop front ball joints and the relocated front LCA rear pivot. Really not that different.

This is also the way people should refer to their front 'ride height' instead of fender arch or frame rail measurements, and is independent of tire heights, etc.


The info I have says ball joint to inner pivot 11mm (7/16) delta, but the info you provided also specifies "measure from the bottom of the ball joint cap".

I always approximate the center of the ball (which is what actually matters)....but apparently they are compensating that in the 11 mm, so it seems I have been trying to run the front too high.

The rear, as measured per Boss 302 instructions sets it up super high.
(I only had the info for the front) I had to lower the front and raise the rear.
There is more than an inch of rake as measured from the pinch points.
That sounds like a lot to me. Any input before I lock the collars down?
 

Grant 302

basic and well known psychic
That's gotta be one of the dimensions to ballpark since you don't have the same Howe units.

I didn't mean for the guidelines to be gospel...food for thought and consideration for baseline. The 302S stuff is still with a panhard.
 

Fabman

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That's gotta be one of the dimensions to ballparks since you don't have the same Howe units.

I didn't mean for the guidelines to be gospel...food for thought and consideration for baseline. The 302S stuff is still with a panhard.
Yes, The rear Roll Center is much higher with the PHB.
I'm going to go with it and see what happens.
 

Fabman

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0a8cf7c24e04b16ff32f56eddb89b0fc.jpg


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Grant 302

basic and well known psychic
0a8cf7c24e04b16ff32f56eddb89b0fc.jpg


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Looks like you don't need that much camber from that shot. Got any more? like 3,4,5,6,9,10? And any from the inside of the turn?
Will there be clearance issues if you reduce neg camber?

I've only been to Laguna Seca once with the FakeR since I got the CorteX parts on. Both Ron and I independently decided to reduce our camber after the first session. Both sides on mine were running hotter on the insides 118-123-133...134-129-124. Pressure was good at 33.2 and 33.0 hot for pirelli DH set 27.0 cold@ 60ºF.
This was still shakedown. 2nd day with the new suspension and I was having trouble with the rear grip that day. I didn't mind running pretty loose on the previous track day at Streets, but don't care for a loose car at LS.

Yes, The rear Roll Center is much higher with the PHB.

Not much higher on mine, but it does rise on right handers. I have it set about level. Which is functionally as low as I can go without relocating things, and works (I think) with how high I keep the RC up front.
 

Fabman

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Looks like you don't need that much camber from that shot. Got any more? like 3,4,5,6,9,10? And any from the inside of the turn?
Will there be clearance issues if you reduce neg camber?

I've only been to Laguna Seca once with the FakeR since I got the CorteX parts on. Both Ron and I independently decided to reduce our camber after the first session. Both sides on mine were running hotter on the insides 118-123-133...134-129-124. Pressure was good at 33.2 and 33.0 hot for pirelli DH set 27.0 cold@ 60ºF.
This was still shakedown. 2nd day with the new suspension and I was having trouble with the rear grip that day. I didn't mind running pretty loose on the previous track day at Streets, but don't care for a loose car at LS.



Not much higher on mine, but it does rise on right handers. I have it set about level. Which is functionally as low as I can go without relocating things, and works (I think) with how high I keep the RC up front.
That's at the top of the cosrkscrew. Its the transition between left and right so it's basically a short straight section. When you look at it in a straight line it looks like a lot of camber but when you look at it fully loaded it looks about right. I just got some new track pics so let me download them to my work computer and see what we have.
 

Fabman

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Wait...look at my sig pic.....thats the setup I'm running now.
 

Fabman

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Fabman

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