Scca Autox Aero

[Regerfab]

I'm thinking about putting a rear spoiler on my fsp 2002 for this year, wondering if you guys had any input. I looked through as many pics I could of your cars and most of you don't have anything. I run with Philly region with street tires (225 rivals) in the very competitive regional only street tire sp/sm class so I have far less grip than most of you guys. I often lose the rear at higher speeds and wondering if a spoiler could help.

[M3M3]

i would think fixing the suspension will have far more effect than any aero aid in an auto-x.

[Pamola]

Don't bother.

 

The speeds that are seen in the Auto X and the shape of our cars means that a rear spoiler is going to be primarily cosmetic.

[Regerfab]

This car is already well prepared for the class in terms of suspension mods allowed. Rear alignment could most likely solve this, but not allowed in class on our cars. Most other street prepared classes have plenty of people with spoilers just don't see any in fsp.

[Preyupy]

As Pamola said at the speeds you can get on any SOLO II course the size of rear wing you would need to make any significant down force would be HUGE.  You would get more down force just from the weight of it than it could possible create aerodynamically.  Look at the wings the guys in A mod run and you get some idea of how much wing you need at 60 mph to make any down force.  With the shape of a 2002 you would need to mount it above the roof height to even get any air to it.   The small spoilers that people run on their road race cars are there primarily to kill lift not produce down force,  at 100 + mph there starts to be lift at the back of the car and killing that lift is much easier than actually creating down force. 

 

If you think you need more weight on the back tires move some if it from else ware in the car towards the rear.  

[steve k.]

I'm thinking about putting a rear spoiler on my fsp 2002 for this year, wondering if you guys had any input. I looked through as many pics I could of your cars and most of you don't have anything. I run with Philly region with street tires (225 rivals) in the very competitive regional only street tire sp/sm class so I have far less grip than most of you guys. I often lose the rear at higher speeds and wondering if a spoiler could help.

 

How do you loose the rear?  Is it in high speed corner or on high speed straights? 

 

Wings are not allowed in FSP, but a NASCAR stile spoiler is. I have a small turbo on the car right now. Due to the roof line, i don't think much air actually goes over it, so it need to be a bit taller to get more effect. I am working on getting the car a bit lower this year and then will revisit the spoiler. 

 

The problem with the rear spoiler is that you will sacrifice top speed for downforce so if you can fix the rear with suspension adjustment, then that would be the better way to go.

 

steve k.

 

 

[AceAndrew]

Yep,  another real world example.  Kevin and Ian's former championship car.

 

 

Can't remember the name of the lady who is racing it at the moment.

[182kartracer]

If you do decide to run a rear wing it will have to be huge to make any downforce. At speeds below 50 it's really hard to make any downforce. I would say focus on your suspension rather than downforce

[M3M3]

 

This car is already well prepared for the class in terms of suspension mods allowed. Rear alignment could most likely solve this, but not allowed in class on our cars. Most other street prepared classes have plenty of people with spoilers just don't see any in fsp.

 

making all the mods allowed and tuning the suspension are two different things. alignment, spring rate, swaybar stiffness, tire pressures, and driving technique are some of the things that could fix the issue. "lose the rear at high speeds" is not very descriptive of the problem.

[jgerock]

Since my AutoX skills are lacking, here is a fun quiz courtesy of an old Roundel Magazine

[Regerfab]

 

How do you loose the rear?  Is it in high speed corner or on high speed straights? 

 

Wings are not allowed in FSP, but a NASCAR stile spoiler is. I have a small turbo on the car right now. Due to the roof line, i don't think much air actually goes over it, so it need to be a bit taller to get more effect. I am working on getting the car a bit lower this year and then will revisit the spoiler. 

 

The problem with the rear spoiler is that you will sacrifice top speed for downforce so if you can fix the rear with suspension adjustment, then that would be the better way to go.

 

steve k.

 

 

 

 

 

 

 

those nascar style spoilers are the ones I was thinking of, I see a lot of them on DSP and CSP prepped  cars. That's what got me wondering if that could give me a little more grip at higher speeds.

 

It will start to come around on me at higher speeds either lifting or steady throttle in corners. The car feels great a lower speeds and It doesn't seam to matter if its bumpy or smooth.

 

 

 

making all the mods allowed and tuning the suspension are two different things. alignment, spring rate, swaybar stiffness, tire pressures, and driving technique are some of the things that could fix the issue. "lose the rear at high speeds" is not very descriptive of the problem.

 

Yeah I know there can be many more things to look at, and I will always be working on tuning more and more. The car really sticks well except for in these certain circumstances. I know I am pretty good on tire pressure as it gets less grip with both more and less pressure. More swaybar tuning is something I am going to be working on this year as well. Unfortunately rear alignment isn't something I can mess with, but there is always more driving technique to improve on.

 

What I was looking for is if anyone else had experience in this class with spoilers. It looks like it will have to be something I will have to find out for myself through some testing this year.

[182kartracer]

From my experience in motorsports their are a couple ways to solve your issue. 

- stiffen up rear end(Bracing)

-stiffer sway bar

-change your turn in approach

 

I would try these out first before you think aero. Remember one change at a time.

[Sneeb]

As Preyupy said, maybe moving weight (battery) to the rear of the car could help a bit. But if it's already back there then scratch that idea. Other suggestion as was said by a few, tweak your suspension till you like how things feel.

[cda951]

As others have said, absolutely exhaust your alignment/sway bar settings before wasting time on aero.

 

What are your alignment settings? What condition are your suspension bushings in? I know that 2002s aren't adjustable in the rear from the factory, but take a good look at your rear toe settings. With the semi-trailing rear control arm design, the rear control arm bushings take a LOT of load and deflect during hard cornering, and this phenomenon can cause what you are experiencing. If the bushings are excessively worn, there will be too much dynamic toe-out of the outside rear wheel while cornering, which will cause a bit of a rear-steer effect and make the rear end unstable. If the rear alignment were adjustable, dialing in some static toe-in on the rear wheels (0.15-0.2 degrees) helps this situation a lot.

 

It doesn't sound like you have adjustable sway bars, so get those before doing anything else. I am relatively new to the 2002 world so I can't tell you which ones are the best, but I work on Porsches for a living and I have a lot of experience setting them up (rear, mid, or front engine) and being able to adjust both ends to your liking is key.

 

Stiffening the front sway bar relative to the rear tends to increase understeer and decrease oversteer, but be careful of going too big or too stiff on the front bar as it might cause massive understeer in tight, low-speed corners.

 

Similarly, stiffening the rear bar will decrease rear end grip relative to the front and shift the balance to oversteer. Again, too big or too stiff can cause too much oversteer, and can even cause the inside rear wheel to lift during corner exit, which is not conducive to traction.

 

The key is to have both ends adjustable and tweak accordingly until you achieve the ideal balance for the conditions.

 

Good luck.