Driving Frustration Setting In

[IsaacMTSU]

I should have said most of them don't. I know some use horizontal springs to fight roll. I was trying to say that sway bars (after a certain point) are grip killers. You want to push more, kill the grip up front by adding a bar. You want to rotate, kill the grip in the rear by adding a bar. This guy at autocross was telling us about how his car (already a competitive car) wouldn't rotate and he didn't like it at all. It would just push everywhere. So, he put a huge front sway bar on it before the event and the car was drifting and rotating all over the place and he loved it. He said "no, it's shaped like a W and when you turn, it pushes your outside down into the pavement and makes it grip better". No amount of talking to him would change his mind.

[steverife]

There is a lot of non-textbook tuning in autocross.

Textbook tuning makes certain assumptions that aren't necessarily true with stock(ish) production cars.

There are a lot of people that just copy other people and maybe get details wrong in explaining what they do. There are very few people that truly understand what they are doing and why it works or doesn't work.

[IsaacMTSU]

There are very few people that truly understand what they are doing and why it works or doesn't work.

+1 on that for sure!

[steverife]

You want to push more, kill the grip up front by adding a bar. You want to rotate, kill the grip in the rear by adding a bar.

I find this a little oversimplified. It makes the assumption that grip is maximized. To increase a push, you decrease front grip in relation to rear grip and vice versa for adding rotation. That is why a front bar sometimes increases rotation on a softer car. You are controlling the front better and increasing front grip.

[IsaacMTSU]

Yep, that's why I said "after a certain point". A little bit is needed to keep your front dialed in. After that, upgrading the front bar kills grip.

edit: I know you know this, I'm just sayin'

[steverife]

I wouldn't even think of choosing a bar until I was on the tires that I planned to run.

[IsaacMTSU]

That's because you are one of the

very few people that truly understand what they are doing and why it works or doesn't work.

[90civichb]

So, if you are not going to choose a bar until you knew what tires you were running, how do you define your tires? Brand, wear rate, compound, sidewall? I am sure there are variations between manufactures (as you can see people trend to what the faster cars are using), but what standard do you use? If you use one at all.

[steverife]

As someone that isn't really going to test, I look at tires that have had success in autocross, then I look at sizing, then I look at reported wear and price and current availability.

Sent from my HTC One V using Tapatalk

[thrdeye]

Yep. Look at results for similar cars and go from there.

For a Miata in STM, the 15 inch Toyo is the tire, unless you don't want to shave, then you could run the Hankook, Dunlop, or Federal and go just about the same pace, most likely.

[steverife]

That's because you are one of the

very few people that truly understand what they are doing and why it works or doesn't work.

I feel like I've read enough to have an okay base, but that's definitely not me.

[Gen52SS]

Driving Paul's car at the Jetport was interesting. If makes EVO school instructors even more impressive. The ability to jump in a car you've never driven and go fast is amazing. I had a lot of difficulty with the paddle shifters and adjusting to the wider rear track. We didn't check pressures between runs and just let the pressure go where it would. After the last run, I measured the temperature profile across the right side tires with a probe pyrometer. It was fairly flat with the inside front only a couple of degrees F cooler than the outside and the rears basically flat. The final tire pressures were 44 front and 38 rear, which is exactly what I'm running on my Mustang.

I only had a serious problem with understeer when I went entered a corner too hot. The gearing wasn't too great. First was too low and second too high. And it needs a front end alignment, badly, and not just for performance. There's enough toe in on the front to visibly feather the outer edges of both front tires. But since the feathering was the same on both sides, at least it doesn't seem to be crab tracking. There's definitely more to get out of the car than I was able to extract, even with the bad alignment.

Speaking of alignment, recommendations on shops? I'd go with zero toe and as much negative camber as they can get without modification.

Okay ...without not seeing all the data from Sunday ...DeWitt is working on that. I did learn a few things which was a good thing. It took 6 runs or more for DeWitt to lay down a better time but once he started to feel the car he did run 1.1 second faster time then me but Clancy's 2011 Mustang now with tires, shocks and bars had a 1.6 second advantage over DeWitt's best time. With a few more runs he might have chipped away more time but I still think 1 second would be the difference. I found I'm turning way too late on the cones. The tire temperaacrossccross the tread cooler on the inside and feathering on the outside after season over will bring the car to a good alignment shop once I find one? Any suggestions?

So my plan is right on schedule keep working on my driving. Before next season put on the new HanKook R-S3 V2's with recommendedcomended alignment setup for Gen 5 Camaro's and autocross. I think working to improve my driving the car will drive at least 1 second faster maybe more...then add tires and alignment I should be much closer....I'll be happy

[CobaltSSlow]

Not to further confuse anyone but I've always head that sway bars have effect on the grip at the opposite end of the car as a function of weight transfer. If the rear bar is stiffer then you are increasing the roll stiffness in the rear allowing the front suspension to load up the outside wheel (why some fwd cars with high rear roll stiffness lift the inside rear tire) and help the car rotate. You also see this in some rwd cars which will lift the inside front under power at corner exit. Obviously having 4 wheels on the ground is usually preferable. Every vehicle will react differently to a front or rear bar of varying stiffness since each car's weight, wheelbase, suspension geometry, tire width and balance are so drastically different. There is probably a much better way of explaining that... But that's the best I can do.

[dewittpayne]

Paul,

You really should get the alignment done as soon as possible. You're wearing your front tires faster than you should and it's probably costing you gas mileage too. Conceivably, it will pay for itself. Unless your wheels are bent, the alignment won't change when you change wheels and tires. If whoever does your routine service hasn't noticed the feathering on the front tires and brought it to your attention, you should think about going somewhere else.

Of course, the data system didn't record my best run.

[dewittpayne]

Not to further confuse anyone but I've always head that sway bars have effect on the grip at the opposite end of the car as a function of weight transfer. If the rear bar is stiffer then you are increasing the roll stiffness in the rear allowing the front suspension to load up the outside wheel (why some fwd cars with high rear roll stiffness lift the inside rear tire) and help the car rotate. You also see this in some rwd cars which will lift the inside front under power at corner exit. Obviously having 4 wheels on the ground is usually preferable. Every vehicle will react differently to a front or rear bar of varying stiffness since each car's weight, wheelbase, suspension geometry, tire width and balance are so drastically different. There is probably a much better way of explaining that... But that's the best I can do.

All other things being equal, which they never are, a stiffer bar increases weight transfer to the outside wheel on the axle where it's installed. Since max lateral g vs load for a tire isn't linear, it decreases with increasing load, a stiffer rear bar, for example, should decrease grip at the rear and increase grip at the front at steady state cornering. Complications include softer springs/bars equal more roll, which means the car reacts to inputs less quickly. A strut suspension starts losing camber if it rolls far enough that the lower control arm starts to angle up. Which is also why, if you can't relocate the lower control arm mounting points, you can lower a strut suspension car too much. But stiffer springs mean you need more damping from the shocks, and that may make the car less stable over bumps.

I do know that a softer rear bar made my car push less, which is not what you would expect from the first order effect of changing weight transfer.