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Would like some autox advice

tamadrummer1120

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So yesterday was my second outing for my s550 in autocross and would like a little advice. Now I will admit I am an autocross amateur. Prior to the s550 I owner an s2000 and autocrossed that a few times. I always try and double enter if space allows so I can run twice as much and get more seat time. For what it's worth, there was about half a dozen 5.0s there yesterday and I was the fastest.

Anyhow this is my daily so I can't make any crazy modifications that some people maybe could. I do have a bmr front subframe brace on the way. Also wheels set up is 20x10 with 275 and 20x11 with 315. Continental dw' s. Not amazing tires but good considering it's a daily.

So I was seeing a pretty good amount of understeer yesterday whenever it came to sharp corners after a high speed zone. I tried various techniques and none seemed to shine above the rest. And though it is inevitable with such a big car, the ending of any slalom became very tasking dude to the body roll. Not sure if a sway bar upgrade would truly fix this or not. I do have to say I saw barely any oversteer unlike any of the other mustang, so I was fortunate there.

Now it was a blessing in disguise that during the morning heats it was raining. I've always thought you learn so much about the car during set autox runs.

Thanks everyone
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TNcoupe

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Scandanavian flick, it will rotate.
 
BmacIL

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Well, sticking to F-street will help you limit the budget on mods.

1. Slot the upper strut hole 2 mm for more camber
2. Rear bar upgrade - I would go GT350R or Strano
3. Dampers - Steeda Pro-action, Koni adjustables
 

Nick610s

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I would think about going to a square tire setup, those big 315s in the back are overpowering the 275's up front. If you continue to autocross this will probably cure 80% of your understeer. Than suspension mods. Shocks, springs sway bars.
 
kz

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He's already way out of F Street. Op - are you sure it's cars fault and you're not simply overdriving the corners ? What tires you're driving on ? More camber and better suspension setup will help with front grip, but tires and driver mod will do the most. Any car will understeer if driven with too much speed at the entry.
 

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NightmareMoon

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Square tires go a long way to curing the oversteer. For me a mildly upgraded rear swaybar (Strano) and a good alignment with camber in the front cured most of the understeer bias. Now the car will oversteer or understeer on demand.

But today in a similar corner to the one you describe I was also pushing wide (understeer) because I was braking too late (or not enough) and not coming off the brake enough to add steering. Result: Front tires overloaded on corner entry and they understeer push through the corner. In other times (like mid-sweeper), if I'm on the gas a bit I can still ask too much of the front tires and get some understeer since the weight is transferred back a bit when you're accelerating

So there is overdriving the front tires and causing understeer, and then there is some factory understeer bias, especially with staggered tires like yours. The car setup bias is fixable (if you're willing to go square). The driver mod is a different story.
 
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tamadrummer1120 said:
So yesterday was my second outing for my s550 in autocross and would like a little advice. Now I will admit I am an autocross amateur. Prior to the s550 I owner an s2000 and autocrossed that a few times. I always try and double enter if space allows so I can run twice as much and get more seat time. For what it's worth, there was about half a dozen 5.0s there yesterday and I was the fastest.

Anyhow this is my daily so I can't make any crazy modifications that some people maybe could. I do have a bmr front subframe brace on the way. Also wheels set up is 20x10 with 275 and 20x11 with 315. Continental dw' s. Not amazing tires but good considering it's a daily.

So I was seeing a pretty good amount of understeer yesterday whenever it came to sharp corners after a high speed zone. I tried various techniques and none seemed to shine above the rest. And though it is inevitable with such a big car, the ending of any slalom became very tasking dude to the body roll. Not sure if a sway bar upgrade would truly fix this or not. I do have to say I saw barely any oversteer unlike any of the other mustang, so I was fortunate there.

Now it was a blessing in disguise that during the morning heats it was raining. I've always thought you learn so much about the car during set autox runs.

Thanks everyone
Click to expand...
If you have a moment, give Rod a call at 1800 950 0774 - he is our resident Autox sales professional - he can speak through your set-up & get you a recommended package.

Best Regards,

TJ
 
Whiskey11

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I guess I'm an odd duck... I found the factory setup to be quite neutral handling on the bigger Nationals style courses I'm used to. So much so that I actually ran a front bar and more negative camber out back on an F-Street car before stock bars and front bars became the cool kid thing to do! :p Having driven an FS car with the rear bar on, it's a handful. Fast, yes, but an absolute pain to keep the rear of the car under it. I know why people do it, but it just isn't my driving style. I get far more consistent results with the BMR front bar full soft.
 
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Whiskey11 said:
I guess I'm an odd duck... I found the factory setup to be quite neutral handling on the bigger Nationals style courses I'm used to. So much so that I actually ran a front bar and more negative camber out back on an F-Street car before stock bars and front bars became the cool kid thing to do! :p Having driven an FS car with the rear bar on, it's a handful. Fast, yes, but an absolute pain to keep the rear of the car under it. I know why people do it, but it just isn't my driving style. I get far more consistent results with the BMR front bar full soft.
Click to expand...
Well you're probably on square tires tho, which do reduce address the factory bias toward understeer and give you a more neutral starting point.

Yeah and it's worth pointing out that the experiments we've seen between cars with front bars and rear bars showed that they're about equally fast, just different styles of driving. Rear bars are fast to rotate on corner entry, front bars are fast to put power down on corner exit.

Personally, I'm pretty comfortable with oversteer, but a tail-happy car can be a scary experience if you're not used to it. It's also why I'm running the Strano bar, which is about the mildest rear bar upgrade you can find. It's significantly less stiff than just using one bar from a BMR or Steeda matched set.
 

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You need a square setup as you have so much more rear grip than front and it is overpowering the front tires.
 

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Nick610s said:
I would think about going to a square tire setup, those big 315s in the back are overpowering the 275's up front. If you continue to autocross this will probably cure 80% of your understeer. Than suspension mods. Shocks, springs sway bars.
Click to expand...
+1
Also, pay attention to the rules. Where is that subframe brace going to bump you? Why not do the 10 more useful mods for that class first (or at least at the same time)?
 
Whiskey11

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NightmareMoon said:
Well you're probably on square tires tho, which do reduce address the factory bias toward understeer and give you a more neutral starting point.

Yeah and it's worth pointing out that the experiments we've seen between cars with front bars and rear bars showed that they're about equally fast, just different styles of driving. Rear bars are fast to rotate on corner entry, front bars are fast to put power down on corner exit.

Personally, I'm pretty comfortable with oversteer, but a tail-happy car can be a scary experience if you're not used to it. It's also why I'm running the Strano bar, which is about the mildest rear bar upgrade you can find. It's significantly less stiff than just using one bar from a BMR or Steeda matched set.
Click to expand...
I absolutely am. 285's at all four corners on factory PP wheels. When it comes to building a car for handling you start at the ground and work your way up through the suspension.

What I mean is, get the tires you are going to be on and square them up at all four corners. This is the foundation you build upon. Every other change will be to make that setup work and the reason why the tires are the most important thing to rule out of the handling bias equation is because they are literally the last thing the forces go through. That makes them absolutely critical.

From there you can start messing with the suspension, but tires are by far the most important aspect to eliminate from the handling bias equation!
 
BmacIL

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Whiskey11 said:
I guess I'm an odd duck... I found the factory setup to be quite neutral handling on the bigger Nationals style courses I'm used to. So much so that I actually ran a front bar and more negative camber out back on an F-Street car before stock bars and front bars became the cool kid thing to do! :p Having driven an FS car with the rear bar on, it's a handful. Fast, yes, but an absolute pain to keep the rear of the car under it. I know why people do it, but it just isn't my driving style. I get far more consistent results with the BMR front bar full soft.
Click to expand...
Nah you're not crazy. There's a reason I went with the springs I did. Wheel rates are perfect for a square setup.
 
SteveW

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OP,

What is your alignment? Try more negative camber and a little toe-out up front.

What were the tire pressures you were running at?

Driver mods: slow in fast out. Brake hard enough before an element that you can be balancing the car with the throttle and accelerating through it, backside cones and realize you can only lose time in tight turns. Make sure you drive down right on top of the apex cone and not chew up a ton of real estate trying to carry speed. Tight turns in autocross suck for everybody ;-)
 
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