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

[ShifterX]

It seems like a good tool, and there is no specific reason to doubt the information. I think my only point is if another source has different numbers, we don’t know for sure who is off. All we know is the end numbers don’t seem to align.

Maybe the take away is the specific numbers from two different sources may not matter so much. More just how each change affects the numbers within a given source.

I think the back to back testing that @RoadRacer78 is doing, is probably more valuable than any numbers, regardless of where they come from. Keep the feedback coming. When you say your gt500 has too little AS, how does that present?

 

[RoadRacer78]

It seems like a good tool, and there is no specific reason to doubt the information. I think my only point is if another source has different numbers, we don’t know for sure who is off. All we know is the end numbers don’t seem to align.

Maybe the take away is the specific numbers from two different sources may not matter so much. More just how each change affects the numbers within a given source.

I think the back to back testing that @RoadRacer78 is doing, is probably more valuable than any numbers, regardless of where they come from. Keep the feedback coming. When you say your gt500 has too little AS, how does that present?

We do have another source (the only one I could find for free) but we don't know if the numbers are different because the calculation is different or if the numbers are different because it asks for two more numbers I don't have to enter. I'd place my bet on the second.

My GT and GT500 make nearly identical power. And in the same way. They have the exact same blower head unit spinning the same speed.

Straight line: The GT500 "hazes" the tires more than the GT does. Simply put, the GT puts the power down better. And the GT500 has a bit more tire under it.

Exiting a corner: The GT500 oversteers more than the GT does. But it oversteers in a very smooth predictable fashion. It doesn't lose or regain traction hard/abruptly. The transitions are smooth as butter. You can easily play with the angle of the car with the throttle. All clear signs that it doesn't have as much bite as it should/ could. If it was a road course car you would be far more consistent with the lower AS number this car has.

The GT requires quite a bit more throttle and intentional steering input to get it to oversteer. When it cuts loose it cuts loose abruptly. Call it "snappy". And when you try and throttle it to hold a certain angle it takes a lot more care because when you let back out of the throttle it wants to hook back up abruptly. You can get the tail out and keep it out there. But it takes a lot more skill and forethought. If it were a road course car it would be hard to consistently make it do the same thing on every corner exit. And far more likely to get way out there, hook up, and then having you pointing in the wrong direction. It has the potential to be a real handful.

Somewhere between the two is the Goldilocks setting.

 

[TeeLew]

Somewhere between the two is the Goldilocks setting.

The Shelby doesn't particularly sound like an anti-squat problem to me. I'm sure it's a contributor, but what are the other variables? Your 50% number sounds a little beefy for best traction, IMO. Anti-squat doesn't add grip, it reduces movement. Softening rear spring/bar off a little would probably help your exit drive.

 

[RoadRacer78]

The Shelby doesn't particularly sound like an anti-squat problem to me. I'm sure it's a contributor, but what are the other variables? Your 50% number sounds a little beefy for best traction, IMO. Anti-squat doesn't add grip, it reduces movement. Softening rear spring/bar off a little would probably help your exit drive.

The GT500 doesn't have a "problem". It has some characteristics that could be more finely dialed in.

More anti squat absolutely improves traction as long as you don't go overboard, shock the tire too hard, and blow the tires off. Overboard being well over 100%.

 

[Fabman]

Since the GT was lowered so much have the bump stops been cut? If not it can hit the stop under load and cause snap oversteer. Typically when the rear is lowered the stops are cut in half or removed to avoid this.

 

[RoadRacer78]

Since the GT was lowered so much have the bump stops been cut? If not it can hit the stop under load and cause snap oversteer. Typically when the rear is lowered the stops are cut in half or removed to avoid this.

Bump stops are cut. No snap oversteer issues at all.

The GT has J&M Extreme Joint arms on it. They have as close to zero bind in articulation as you can get. With the pumpkin on a jack and no springs installed you can articulate the rear end with a couple fingers. I didn't "test" for this. I did it by accident when I was putting the rear end at ride height to set the pinion angle. I was shocked how easy it was to articulate the rear end as I was getting it level.

 

[Fabman]

Bump stops are cut. No snap oversteer issues at all.

The GT has J&M Extreme Joint arms on it. They have as close to zero bind in articulation as you can get. With the pumpkin on a jack and no springs installed you can articulate the rear end with a couple fingers. I didn't "test" for this. I did it by accident when I was putting the rear end at ride height to set the pinion angle. I was shocked how easy it was to articulate the rear end as I was getting it level.

I'm familair, I used to run those same J&M arms. Next best thing to rod ends.

 

[RoadRacer78]

I'm familair, I used to run those same J&M arms. Next best thing to rod ends.

Yeah, best street compromise out there.

 

[ShifterX]

We do have another source (the only one I could find for free) but we don't know if the numbers are different because the calculation is different or if the numbers are different because it asks for two more numbers I don't have to enter. I'd place my bet on the second.

My GT and GT500 make nearly identical power. And in the same way. They have the exact same blower head unit spinning the same speed.

Straight line: The GT500 "hazes" the tires more than the GT does. Simply put, the GT puts the power down better. And the GT500 has a bit more tire under it.

Exiting a corner: The GT500 oversteers more than the GT does. But it oversteers in a very smooth predictable fashion. It doesn't lose or regain traction hard/abruptly. The transitions are smooth as butter. You can easily play with the angle of the car with the throttle. All clear signs that it doesn't have as much bite as it should/ could. If it was a road course car you would be far more consistent with the lower AS number this car has.

The GT requires quite a bit more throttle and intentional steering input to get it to oversteer. When it cuts loose it cuts loose abruptly. Call it "snappy". And when you try and throttle it to hold a certain angle it takes a lot more care because when you let back out of the throttle it wants to hook back up abruptly. You can get the tail out and keep it out there. But it takes a lot more skill and forethought. If it were a road course car it would be hard to consistently make it do the same thing on every corner exit. And far more likely to get way out there, hook up, and then having you pointing in the wrong direction. It has the potential to be a real handful.

Somewhere between the two is the Goldilocks setting.

Great description and practical comparison.

What is the pitch behavior like of both cars? Do you have a similar spring/damper package?

Also what is the off throttle behavior like in the GT? Does it rotate better or worse under braking?

 

[blacksheep-1]

You need a ton of squat to get an S197 to get off the corner, and I mean inside front tire pulling squat.

 

[RoadRacer78]

You need a ton of squat to get an S197 to get off the corner, and I mean inside front tire pulling squat.

Yeah, I'm not sold on the drop brackets. I would like to feel what 50% AS is like at some point though.

 

[RoadRacer78]

Great description and practical comparison.

What is the pitch behavior like of both cars? Do you have a similar spring/damper package?

Also what is the off throttle behavior like in the GT? Does it rotate better or worse under braking?

Both cars have the same spring rates. The GT has Bilstein B6's. The GT500 has the stock Performance Pack dampers. They're red. I think they're Tokico's? I have some B6's for it. Just haven't had the time to install them. The GT is lower the the GT500 though so the geometry is different. The front bars are the same. The GT500 has a bit more rear bar than then GT but I have a bar with the same rate as the GT500 waiting to go on/test.

The GT pitches forward more going into corners. More than I would like. It has that "falling" feeling. I suspect if I fix the front roll center with some longer ball joints it will move in the right direction.

I don't have a spot that I can run the cars in hard enough to feel how they rotate. I mean I could............Probably not a great idea though. This getting older and being more responsible thing is limiting.

I want to get longer ball joints and the bigger bar on the GT and the Bilstein's on the GT500 so the two cars are more apples and apples. I think at that point I'll be able to get a better feel for what the difference between 35% and 77% AS does all around. And then I would like to feel 50%. I know how I would do it. It will be quite a bit of work. Welding, drilling, grinding, etc. And I don't have much spare time right now.

 

[DaveW]

spring rate is your friend on the pitching.

Unless you do the weld in Howe conversion, the off the shelf Steeda extended ball joints seem to have a habit of breaking which is not a good thing for a ball joint. Tread carefully IMO

 

[RoadRacer78]

spring rate is your friend on the pitching.

Unless you do the weld in Howe conversion, the off the shelf Steeda extended ball joints seem to have a habit of breaking which is not a good thing for a ball joint. Tread carefully IMO

I don't have a pitch issue with the GT500 that has the same rate springs and front bar. And I don't want more rate because the Bilstein's are already on the limit (or a bit past) of the rebound circuit.

Yeah, I know about the ball joint issue with the 2005-2009 control arms. Which unfortunately I just replaced. The later S197 arms have bigger ball joints or something and are supposed to be more reliable. So I need ball joints and arms. Yay.

What is the Howe conversion? Link? Thanks

 

[TeeLew]

The GT500 doesn't have a "problem". It has some characteristics that could be more finely dialed in.

More anti squat absolutely improves traction as long as you don't go overboard, shock the tire too hard, and blow the tires off. Overboard being well over 100%.

At a drag strip on a prepped track, yes. On a road course, no, increasing A/S does not increase rear grip.

It shifts the longitudinal load transfer from springs, which are squishy, to the suspension links, which shouldn't be. Stiffening the rear on throttle doesn't add grip. It doesn't matter if you do it through springs, bars, dampers or geometry. It all does the same basic thing, just differently.

 

[TeeLew]

You need a ton of squat to get an S197 to get off the corner, and I mean inside front tire pulling squat.

A car is like a primate. It must squat to go.

 

[RoadRacer78]

At a drag strip on a prepped track, yes. On a road course, no, increasing A/S does not increase rear grip.

It shifts the longitudinal load transfer from springs, which are squishy, to the suspension links, which shouldn't be. Stiffening the rear on throttle doesn't add grip. It doesn't matter if you do it through springs, bars, dampers or geometry. It all does the same basic thing, just differently.

Set your car up with zero anti squat and get back to us with the results.

 

[DaveW]

I don't have a pitch issue with the GT500 that has the same rate springs and front bar. And I don't want more rate because the Bilstein's are already on the limit (or a bit past) of the rebound circuit.

Yeah, I know about the ball joint issue with the 2005-2009 control arms. Which unfortunately I just replaced. The later S197 arms have bigger ball joints or something and are supposed to be more reliable. So I need ball joints and arms. Yay.

What is the Howe conversion? Link? Thanks

I broke multiple 2012 ball steeda ball joints and have not been the only one. So its on the later cars.

https://shop.watsonracing.com/HOWE-EXTENDED-BALL-JOINT-BALL-JOINT-ONLY-p/wr-22409.htm

I am not sure the juice is worth the squeeze here. My car gained/lost no speed when I went from standard>extended>back to standard ball joints.

Everything except spring rate is a band aid for pitch no matter if its on a GT or GT500 A half inch change to roll center that's probably 8 inches under ground, or 10% anti squat is not going to change that. Though I do appreciate the discussion and thinking around the angles and understand we all have to try things our own way.

 

[Fabman]

I don't have a pitch issue with the GT500 that has the same rate springs and front bar. And I don't want more rate because the Bilstein's are already on the limit (or a bit past) of the rebound circuit.

Yeah, I know about the ball joint issue with the 2005-2009 control arms. Which unfortunately I just replaced. The later S197 arms have bigger ball joints or something and are supposed to be more reliable. So I need ball joints and arms. Yay.

What is the Howe conversion? Link? Thanks

If you go with the later 19mm ball joints you’ll need to bore the spindle to fit them. I have a fixture that I use to align them in the mill so the holes are straight. I also clamp a small piece of material in the slot so the cut isn’t interrupted which could break the cutting tool. Or you could just buy the later 19mm spindles. The Howe kit is a Chrysler screw in ball joint body. Much beefier with a weld on bung. These are widely used on race cars.

 

[RoadRacer78]

I broke multiple 2012 ball steeda ball joints and have not been the only one. So its on the later cars.

https://shop.watsonracing.com/HOWE-EXTENDED-BALL-JOINT-BALL-JOINT-ONLY-p/wr-22409.htm

I am not sure the juice is worth the squeeze here. My car gained/lost no speed when I went from standard>extended>back to standard ball joints.

Everything except spring rate is a band aid for pitch no matter if its on a GT or GT500 A half inch change to roll center that's probably 8 inches under ground, or 10% anti squat is not going to change that. Though I do appreciate the discussion and thinking around the angles and understand we all have to try things our own way.

Yeah, the ball joint thing sounds like a can of worms that i don't want to open to solve this "problem" (description of problem below).

I'm trying to solve an unsolvable problem. A good handling street car suspension that is lowered too much, rides pretty nice and doesn't break the bank. This is what the customer base wants. It doesn't matter that they are wrong for having unreasonable expectations. They want what they want. Slammed generally being priority #1.

If I was trying to solve for more performance more spring rate would be the direction along with dampers with more control/ adjust-ability.

Right now the GT and GT500 are pretty good. Good enough to where you really do need harnesses to stay in the seats. Do you need more than that for a street car? Does 98% of the customer base have the skills to push the car that hard? Also no. I'm still going to refine what I have going on as much as I can though as long as it doesn't break the bank or ruin the ride. It sounds like I'm down to anti roll bars now. I have some adjustable Eibach units to play with. I'll play with them a bit and see what it gets me. And if it's worth adding them to the "package".