S197 Anti Squat Numbers/ Theory/ Real World Results/ Etc

[ShifterX]

I didn't do the math, but removing the relocation brackets drastically improved my braking stability, and along with softening the rear springs a bit, gave me much more confidence powering out of turns. I have not noticed any downsides to removing the brackets.
I'm sure if I drag raced I might miss them.

When you added the brackets did you notice any change? Assuming you were using the upper hole?

 

[noldevin]

When you added the brackets did you notice any change? Assuming you were using the upper hole?

I added them 8 years ago when it was still a street car "because that's what you do"
They went on with a bunch of other stuff, so no not really.
I had them on middle hole and went to upper hole and finally removed them.

 

[navseng]

All this is really pretty meaningless without real life numbers. Even for a "stock suspension" car. If the car is lowered or had weight reduction to alter the CG then these values will change.

 

[Dave_W]

The way I look at anti-dive and anti-squat is that you're changing how much weight transfer under braking or acceleration is happening through the suspension linkage vs the springs & shocks. If you have 100% anti-dive and anti-squat, then all the longitudinal weight transfer happens through linkages and none through springs & shocks. And it happens instantly. This means you can't use springs & shocks to tune handling during longitudinal weight transfer. Having less anti-dive & anti-squat means you can use your shocks to tune & time the longitudinal weight transfer, just as you can use shocks to tune & time lateral weight transfer (if the roll center isn't at CG). If you're using a "soft spring & big bar" style suspension, you can keep the dive & squat under control by running higher anti-dive & anti-squat percentages.

 

[RoadRacer78]

225 F, 195 R or so I have read. They feel pretty soft, at least initially. Could be their progressive nature. Add to that the konis are a little slow to build damping force.

My interest in drop brackets stems more from the experimental side. Most cars I have setup for track driving are irs so changes to anti squat are usually not an accessible option. There is something appealing to being able to make fundamental changes to the suspension design. Even on a trial and error basis.

Off Topic.....

IDK how the track community as a whole feels about progressive rate springs.......but I HATE them. Take corner entry as just one example. I need a spring that is linear because I want to turn into the corner and load the contact patches linearly. In my experience progressive springs "crash" through the initial part of the travel and then run into a "wall' when they get into the meat of their rate. This is not the way to smoothly but aggressively turn into a corner. Again, IMO.

Additionally, it is possible (depending, depending, depending) that progressive rate springs cause the dampers to get into their high speed valving (more aggressive) at the beginning of the stroke and then into the low speed valving at the end of the stroke. One, this could feel really weird. Two, that may add a really weird situation over bumps.

Something to consider.

 

[RoadRacer78]

All this is really pretty meaningless without real life numbers. Even for a "stock suspension" car. If the car is lowered or had weight reduction to alter the CG then these values will change.

Those can be accounted for using this calculator.
Instant Center calculator

Yeah, I know that it's not the same as measuring the car and a calculator like this is only a "guess'. But it's a close guess that at least can show you direction and scale. For example, take a stock S197's numbers and just change the the LCA mounting point. You will pick up about 60% in AS. Then go out and drive the car before and after. You will be able to feel it and it will give you the feedback you need to put that scale into perspective.

 

[ShifterX]

Off Topic.....

IDK how the track community as a whole feels about progressive rate springs.......but I HATE them. Take corner entry as just one example. I need a spring that is linear because I want to turn into the corner and load the contact patches linearly. In my experience progressive springs "crash" through the initial part of the travel and then run into a "wall' when they get into the meat of their rate. This is not the way to smoothly but aggressively turn into a corner. Again, IMO.

Additionally, it is possible (depending, depending, depending) that progressive rate springs cause the dampers to get into their high speed valving (more aggressive) at the beginning of the stroke and then into the low speed valving at the end of the stroke. One, this could feel really weird. Two, that may add a really weird situation over bumps.

Something to consider.

I have always spec’d my dual purpose cars with straight rate springs. With the correct damping profile, there is little penalty to ride. Koni yellows specifically are a small piston, slow response damper, especially in compression. IMO, they pair nicely with a straight rate spring, on the stiffer side.

But not to get too off topic. I can attack my excess pitching by trying to find a different spring for the konis, scrap the oem style setup and get into a coilover, like GC, or go with some trailing arm brackets.

Not sure if this was mentioned, but is there a bolt on bracket that has a hole closer to oem than 2”?

 

[blacksheep-1]

Look up the sticky
Blacksheep hates Watts linkages

There is a whole history there including a side by side with a watts vs panhard

Thread 'Blacksheep Hates Watts Linkages' https://trackmustangsonline.com/threads/blacksheep-hates-watts-linkages.13278/

 

[RoadRacer78]

Not sure if this was mentioned, but is there a bolt on bracket that has a hole closer to oem than 2”?

Sorta. Steeda has a bracket where the top hole is 1.15" down from stock. But I don't see how that would work without drilling through the stock brackets (the holes will be blocked). Not a big deal. But something to factor in. Everything else I have found the top hole is 2" away from stock.

I went down the rabbit hole again this morning on drop brackets, IC length, IC height, etc to see if I could find a set of suspension point that looked good "on paper".

Keep in mind this is on my car at my ride height with my tire height, etc. But, the differences or the percentage of change is going to be pretty similar across most car combo's.

Stock LCA mounting point = 34.67% AS

LCA drop 2" = 94.27% AS

LCA drop 1.5" = 80.98% AS

LCA drop 1.0" = 66.70% AS

LCA drop .75" = 59.15% AS

LCA drop .5" = 51.30% AS

I'd like to try the .5" and .75" locations but that would take a LOT of custom work (cutting, welding, drilling, etc). Not something I have time for right now. The Steeda brackets may be a "good enough" thing to try. I know what stock and 85% AS feel like. They are light years apart from each other. Feeling something in the middle and recording it with the butt dyno and filing that info away would be nice.

 

[Fabman]

The way I look at anti-dive and anti-squat is that you're changing how much weight transfer under braking or acceleration is happening through the suspension linkage vs the springs & shocks. If you have 100% anti-dive and anti-squat, then all the longitudinal weight transfer happens through linkages and none through springs & shocks. And it happens instantly. This means you can't use springs & shocks to tune handling during longitudinal weight transfer. Having less anti-dive & anti-squat means you can use your shocks to tune & time the longitudinal weight transfer, just as you can use shocks to tune & time lateral weight transfer (if the roll center isn't at CG). If you're using a "soft spring & big bar" style suspension, you can keep the dive & squat under control by running higher anti-dive & anti-squat percentages.

Boom-this. ^^^

 

[blacksheep-1]

Press release...

 

[blacksheep-1]

Sorry, wrong thread very tired with all that's going on

 

[RoadRacer78]

225 F, 195 R or so I have read. They feel pretty soft, at least initially. Could be their progressive nature. Add to that the konis are a little slow to build damping force.

My interest in drop brackets stems more from the experimental side. Most cars I have setup for track driving are irs so changes to anti squat are usually not an accessible option. There is something appealing to being able to make fundamental changes to the suspension design. Even on a trial and error basis.

I'd wager a lot of what you're feeling for squat is down to the progressive springs. Frankly, I detest progressive springs in every way. If someone asked me to sort your car out the first thing I would do is go linear rate. Not try and tune around the progressiveness.

 

[Fabman]

I'd wager a lot of what you're feeling for squat is down to the progressive springs. Frankly, I detest progressive springs in every way. If someone asked me to sort your car out the first thing I would do is go linear rate. Not try and tune around the progressiveness.

Yeah, I hate progressives too….

 

[blacksheep-1]

Yeah, I hate progressives too….

Agreed, progressives for a street car is not so bad, but for a track car, I'd prefer non progressive.
That being said, the Ford Performance " kits" are progressive and they work very well. Probably because they are designed specifically for the application and have been tested as such.

 

[Mad Hatter]

Well Coil-overs are usually linear so they are easier to setup . if I remember right, the ford P springs were only progresive in the rear?? that would make some sense.

 

[RoadRacer78]

Agreed, progressives for a street car is not so bad, but for a track car, I'd prefer non progressive.
That being said, the Ford Performance " kits" are progressive and they work very well. Probably because they are designed specifically for the application and have been tested as such.

From the people I know and what I know from them of how Ford Racing Parts works I don't believe for a second that there was any testing involved other than "yeah, those fit".

IMO progressive springs have no place on the street either.

 

[Fabman]

Agreed, progressives for a street car is not so bad, but for a track car, I'd prefer non progressive.
That being said, the Ford Performance " kits" are progressive and they work very well. Probably because they are designed specifically for the application and have been tested as such.

I wasn’t talking about springs….

 

[RoadRacer78]

I wasn’t talking about springs….

Should have used the sarcasm font.

 

[JDee]

Agreed, progressives for a street car is not so bad, but for a track car, I'd prefer non progressive.
That being said, the Ford Performance " kits" are progressive and they work very well. Probably because they are designed specifically for the application and have been tested as such.

100% agree. I had the Ford Racing full track kit on my '16 and it absolutely transformed that car. It punched way beyond its weight with that kit and a full set of aftermarket poly bushings. It also was really nasty to drive on the street due to the poly bushings. But it was a blast to drive on the track.