No stupid questions here Josh, it's all good. I learned to do my best to remove ego from racing a long time ago. If you take the mindset that you are always a student (some students are more knowledgeable than others) than you can never feel stupid for asking an intelligent question.

In this case, don't get hung up on just thinking about one generalized effect of making a shock adjustment, like how fast the mass of chassis transfers load on the wheels. In this case, we are attacking the problem of "If my inside rear wheel is getting light, (i.e. lifting off the tarmac under full body roll, or getting really light/nearly lifting), causing the rear of my car to lose traction relative to the front because my diff is opening, how can I stop that from happening?" By taking out rear rebound, you are letting that inside wheel return to full droop quicker than before, allowing it to remain loaded against the ground, preventing that diff from opening up too much while at the same time getting some mechanical grip back from the inside tire. Also, it's typically a very good idea to make adjustments to the side of the car that needs it before you adjust other areas of the car. Adding rear LS compression will decrease the rate of roll at the rear of the car, giving a chance for that inside wheel to stay loaded for a great period of time in the corner.

Regarding spring rate, I thought that the spring rates Mark Melchior had on at 2011 STR Nationals were just about perfect for RS3's. I'll be starting with those rates if I go to STR next year.

Nick

 

After watching the vid, the first thing that occurred to me is your over sprung, and over running the rear tires before they have a chance to settle in and grip. Less aggressive camber could help, a little less tire pressure, less slow speed compression, less sway bar, are all options available to you to play with. Probably less compression would be the first and easiest thing to try, but if your already pretty balanced there to the spring rate your running, you probably just need less spring. Or add more tire in the back if possible.

And fyi, I think why some are recommending to take rebound out of the rear, is based on the suspected notion that your inside rear is light and causing to loose traction, so getting it to return to the ground quicker under transition could help some, but as mentioned above, I don't think this is the issue, I think your just over sprung for the tire grip level, your over running the rear from steering input alone, let alone being on the gas so your out of balance at entry and exit.

 

I just watched the video too:

You are VERY aggressive with your throttle input sometimes. I would focus on being delicate and managing your feed-in of throttle instead of treating it like an on/off switch sometimes. You do have some good moments though, keep it up. Also, I see you are REALLY aggressive on your steering input sometimes, tending to overdrive the front, requiring you to set the car up to be a little looser than is optimal in order to combat the understeer. We are getting in to a driver-specific setup quandry at that point though, so it's up to you what you want to focus on.

I also would not be running 1/4" toe in on an AP2 rear subframe. That can cause the rear of the car to do some weird shit. I would go to 1/8" or less. Despite intuition you may find the car to be more stable and have a gradual breakaway at peak grip with that setting. 1/16" in feels great on my star spec Z1's, but that's a stock class setup, so YMMV. I am also not exactly privy to what the hot STR setup is right now, I am just going off my own experience.

An off-topic on PAX- it's great to take top PAX, I love it and go for it all the time. But don't get too hung up on it. If you do well on PAX, be happy, but it's not the be-all end all metric of your performance. At the end of the day, all I really care about is beating the other guys in the same equipment as me. Course dependency, track surface and many other factors contribute to a PAX ranking. Consider it a loose, but generally good ballpark indicator of how you are driving relative to your competitors.

 

Thanks for the input guys! This is the 4th event in the car and really trying to figure it out. For sure to agressive with throttle, my AP1 would let me get away with that, this car seems to light up the tires. HaHa. I'll go change the rear toe before my next event but shouldn't decressing the rear toe make the car looser?

That makes sense what you said about the shock changes. My last car worked great with these settings and RS3s. You see where I'm at on the current car. HaHa. It did fine on the slick surface but was near undrivable on the grippier lot.

 

This may help you nick! My friend just tagged my in it on facebook...

 

What happens when you have more grip, you have the ability to turn harder, where's the weight go? to the front.

First choice would be more front roll rate.
Second would be more front comp.
Third less rear comp assuming you're running enough to start with.
Fourth more rear rebound but really dependent on entry attitude of rear.


As far as a damper change rear comp would be my first choice still.

I've always been told about the rear wheel lift. I've only experienced it once and it was in someone else's car, never in mine. The only thing that I noticed was there was no drive. Too much rear rebound was the cause, since I'm not a believer in rebound as the main chassis control is probably why I've never had any negative issues with rear wheel lift.


Link to video? Don't think I'm subscribed to you.
After watching the video on my phone it looked like the looseness started off throttle vs on throttle so I would say lack of front grip might be the start of the problem and the result of trying to gain front grip by getting off throttle was the issue? Just a thought and probably isn't correct.

 

You're welcome Josh. Yeah regarding the rear toe, I also went through the learning process of evaluating more/less toe in. Glagola and Marc P have commented on this in the past also. As you increase toe-in you are building in more drag and static slip angle to the rear tires. This is good for minimizing the amount of yaw the car needs before it takes a "set" during peak load. But the problem is that as you increase rear toe-in, you make the difference between the "target rear slip angles" at each rear tire much greater, to the point where they can add alot of "inconsistency" to the rear of the car as they load and unload. The car has to rotate less to get to peak grip on one side, but now the other tire is experiencing much less of a slip angle. So it's easy to "over do" the rear toe in. I tried a couple variants greater than 1/4" on my AP1, and all it did was make the car even twitchier and more inconsistent. It would go from a super tight feeling to a twitch with very little warning. Running less rear toe in on the car made the transition from "little grip" to "peak grip" more consistent and gradual. The AP2 has the benefit of a more gradual toe curve. I like it better than the AP1 and would make an argument it is "faster" than the AP1 geometry as a result. Again YMMV. Test it and see what you experience for your driving style.

Edit: In your last pic, the cone is blocking it, but it looks like your inside wheel may be lifting there.

 

Mac, video was posted in post #6

link-
https://vimeo.com/66529664

 

Yup, I was too slow with my typing lol thank you

BTW you made some nice corrections

 

Hahaha! That was like RallyCross!