Trail Braking and Rotation Questions

[Racecomp Engineering]

More camber up front. Definitely more camber up front. Especially since the rates you're running aren't terribly stiff.

Even pads all around as you mentioned you were planning on doing.

Do you feel like you're actually losing a significant amount of time? A little stability can be a good thing too. At least we're all talking about solutions that don't involve reducing rear grip.

- Andy

[Dezoris]

Originally Posted by Racecomp Engineering

More camber up front. Definitely more camber up front. Especially since the rates you're running aren't terribly stiff.

Even pads all around as you mentioned you were planning on doing.

Do you feel like you're actually losing a significant amount of time? A little stability can be a good thing too. At least we're all talking about solutions that don't involve reducing rear grip.

- Andy

I think I can get about -.5 more out of the plates before having to lower more but not much more than that.

Let me just say the car is quick, very stable. This was my first time out with the Ohlins in autox and managed a top 10 finish and 2nd in class with some seasoned drivers. But where I am losing time is where I can't get the car to rotate through these tight sections under braking. Something that other RWD cars I have driven do well. S2000 obviously is a different animal however it's fast because you can trail brake with zero effort.

I can come in hot under braking and the car will start to rotate around the corner without having to steer my way through it.

So for the FRS I don't want to make changes that will de-stabilize the car however I was looking for ways to be able to dial in more rotation when I need it thats why I posted for feedback.

[wparsons]

I would add more front camber, and drop the pressure a bit (unless you're already really low) up front.

[Racecomp Engineering]

I would start with the camber and pads.

A click or 2 firmer on the rear shocks would be fun and free to try.

- Andy

[iLuveKetchup]

The sony cams picture quality doesn't look any better than a GoPro. Or am I missing something?

[SubiePig]

What tire pressures were you running the RS3's at?

[Sargy]

drop rear tire pressure, increase rear dampening. I started noticing trail braking after this and it was sufficient enough to play around with.

dosen't even have to be a lot of stiffening in the rear. I realized it and it help with my times.

also my rear toe was set to zero and camber was -1.5

[Dezoris]

Originally Posted by iLuveKetchup

The sony cams picture quality doesn't look any better than a GoPro. Or am I missing something?

Image stabilization is leaps and bounds better. Can't really judge image quality on Youtube too well.

Originally Posted by SubiePig

What tire pressures were you running the RS3's at?

Found the best pressures were usually 33F HOT and 34R HOT

Originally Posted by Sargy

drop rear tire pressure, increase rear dampening. I started noticing trail braking after this and it was sufficient enough to play around with.

dosen't even have to be a lot of stiffening in the rear. I realized it and it help with my times.

also my rear toe was set to zero and camber was -1.5

Something else to try.

[Dezoris]

So I think the issue is front Camber. (I have resisted)
Will -2.7Front be ok, because thats the max I can go before lowering more.

I swapped in the 1521s at all four corners and bedded them.

Lately I am annoyed with the Sprint Kit because the pedal is so firm with so little travel it makes it hard to modulate. I dont know if its because the pads are so damn tight with no piston travel or what. Any feedback?

My first two runs I had no brakes, it was absurd. Then they came on but never got any rotation. ZERO trail braking.


@SubiePig @Racecomp Engineering @wparsons @CSG Mike @rice_classic




Here is the video:

[ame="https://www.youtube.com/watch?v=Y9nxQyZRc9g"]Supercharged FRS Passenger AutoX Runs | In Car Only - YouTube[/ame]

[rice_classic]

Originally Posted by Dezoris

So I think the issue is front Camber. (I have resisted)
Will -2.7Front be ok, because thats the max I can go before lowering more.

I swapped in the 1521s at all four corners and bedded them.

Lately I am annoyed with the Sprint Kit because the pedal is so firm with so little travel it makes it hard to modulate. I dont know if its because the pads are so damn tight with no piston travel or what. Any feedback?

My first two runs I had no brakes, it was absurd. Then they came on but never got any rotation. ZERO trail braking.

I don't know if 2.7 will be enough with out a temp gauge and measuring but considering the Mac struts and what other's have mentioned, you should probably be going more aggressive than that.

At the 56 second mark (right hander), you are doing a combo; entering a bit too fast and then turning the wheel too much which accentuates the understeer already happening but as the car slows from scrubbing it then hooks up. Try disconnecting the sway. While the front end work better without maximizing contact patch (probably more camber), remove the front sway will allow more front end squat and may unload your inside rear enough to help rotation. Like I said, it's an easy thing to disconnect/reconnect. An easy thing to test.

As for the brakes. Having a rock hard brake pedal is a driver's dream. Having a brake pedal that uses a longer stroke, such as a smaller bore MC, is more difficult (for me) to modulate because the modulation is more of a result of pedal distance or movement vs pedal pressure. It's easier for my foot to modulate pressure when less pedal distance is involved.

Until that front end is working better, don't overcook your entry speed.


p.s. if you want to get loco up in hurrrr. Make your rear tires slightly toe out. That will definitely help rotation.

[CSG Mike]

@Dezoris your car is understeering quite a bit. I'd recommend you get QUITE a bit more camber. Start at -3.2, and don't lower the car too much.

As for the brakes, try altering your seating position to be 1 or 2 notches closer to the pedals and steering wheel.

[jprice130]

Watching your recent AutoX videos make me SO thankful for the sites my region has available in NC/SC. We have 3 sites within a couple hours of each other that your supercharger would love. The lot you compete on seems very frustrating; especially if you have a supercharger. Do you have any sites that are larger and more open?

Anyway, back on topic. I compete with -2.7 degrees of camber upfront and -2.2 in the rear and I still get a fair amount of understeer myself. I have a Whiteline 20mm front sway bar that I initially set to stiff, but I am going to move it to the soft setting and see how that works before I alter my alignment. It seems that disconnecting the front sway completely would be a bit drastic for AutoX, but it would be an easy adjustment to make for experimental purposes.

Also, I definitely agree with riceclassic on the amount of steering input you're giving the car in the sweepers at times. Our brains naturally think, "hey, the car is not turning, so I must turn more!" and this definitely makes understeer worse and will put a lot of strain on your outside front tire. I suffer from this habit and it usually means I'm entering corners too hot. Entering corners a little easier and reducing your steering input should help, but I think more front camber and some shock adjustments will be necessary as well.

[rice_classic]

Just food for thought. Even a dreidel would understeer if you enter a corner too hot.

Trail braking should be done at the ending of your braking moment. Your braking moment needs to happen with the wheel straight and the 2nd half of the braking moment will be turn in, will be the actual trail-braking.

Let's go way back for a moment.. Think about driving to the autocross and you're approaching a stop light. As you apply the brake you do so gradually at first and firmer as you come to rest. When you're high performance driving (autox, racing, et al) you are going to do the opposite. In the initial phase of applying the brakes you will "roll-onto them" very hard (hardest application of brakes is at the beginning), then as your approach your corner you're rolling off of them before rolling onto the throttle.

If we braked on the track like we did on the street we will often suffer awful understeer or oversteer on corner entry depending on setup.

If we braked on the street like we did on the track we will often experience being rear-ended.

Apologies if I'm reiterating technical theory you already know but I keep watching that right-hander at 56 seconds it appears you get on the brakes after you've already started turning. Now in Autox, you don't often have a chance to brake straight then turn but at that corner you did. And I know it's a reality that everything happens very fast in autox.

Then I noticed the kicker.. the big kicker, the left hander immediately following it, at the 1:00 mark, you're on throttle and you're understeering.. on throttle. That's the round peg to the round hole right there. That immediately tells me the rear of your car out performs the front of your car and it's this balance that needs remedying. So beating a dead horse here. Make the front work better. That's your low-hanging fruit.

[Dezoris]

Originally Posted by jprice130

Watching your recent AutoX videos make me SO thankful for the sites my region has available in NC/SC. We have 3 sites within a couple hours of each other that your supercharger would love. The lot you compete on seems very frustrating; especially if you have a supercharger. Do you have any sites that are larger and more open?

Anyway, back on topic. I compete with -2.7 degrees of camber upfront and -2.2 in the rear and I still get a fair amount of understeer myself. I have a Whiteline 20mm front sway bar that I initially set to stiff, but I am going to move it to the soft setting and see how that works before I alter my alignment. It seems that disconnecting the front sway completely would be a bit drastic for AutoX, but it would be an easy adjustment to make for experimental purposes.

Also, I definitely agree with riceclassic on the amount of steering input you're giving the car in the sweepers at times. Our brains naturally think, "hey, the car is not turning, so I must turn more!" and this definitely makes understeer worse and will put a lot of strain on your outside front tire. I suffer from this habit and it usually means I'm entering corners too hot. Entering corners a little easier and reducing your steering input should help, but I think more front camber and some shock adjustments will be necessary as well.

Here are my times for the runs:

57.780 57.808 57.695 57.370 57.583 57.509 57.001 57.367 (Fastest runs, lowered pressures back down to normal)

I have to say that I realize there was room for improvement namely in the sweeper. I should have been braking earlier and straighter.

My biggest complaint is the car should be unloading and rotating under braking at that point. I tried braking straight, early, late.
The S2000 you dont even have to try and the car will rotate under braking. If I could have gotten the car to even rotate 30% under braking I would be at least 1 second faster. But the car behaves more like a FWD car. Plows under braking, early or late. Where I had to add more steering it was a car of coming in too hot and having to correct. My competitors who rode with me said: "Car understeers too much"

Originally Posted by rice_classic

Just food for thought. Even a dreidel would understeer if you enter a corner too hot.

Trail braking should be done at the ending of your braking moment. Your braking moment needs to happen with the wheel straight and the 2nd half of the braking moment will be turn in, will be the actual trail-braking.

Let's go way back for a moment.. Think about driving to the autocross and you're approaching a stop light. As you apply the brake you do so gradually at first and firmer as you come to rest. When you're high performance driving (autox, racing, et al) you are going to do the opposite. In the initial phase of applying the brakes you will "roll-onto them" very hard (hardest application of brakes is at the beginning), then as your approach your corner you're rolling off of them before rolling onto the throttle.

If we braked on the track like we did on the street we will often suffer awful understeer or oversteer on corner entry depending on setup.

If we braked on the street like we did on the track we will often experience being rear-ended.

Apologies if I'm reiterating technical theory you already know but I keep watching that right-hander at 56 seconds it appears you get on the brakes after you've already started turning. Now in Autox, you don't often have a chance to brake straight then turn but at that corner you did. And I know it's a reality that everything happens very fast in autox.

Then I noticed the kicker.. the big kicker, the left hander immediately following it, at the 1:00 mark, you're on throttle and you're understeering.. on throttle. That's the round peg to the round hole right there. That immediately tells me the rear of your car out performs the front of your car and it's this balance that needs remedying. So beating a dead horse here. Make the front work better. That's your low-hanging fruit.

Thanks , will start adding more camber up front since that easy to do. Maybe disconnect end links too mid day at next event if the camber does not work.

I have driven other RWD cars and I don't have issues with braking, and trail braking like I do on this car. If you watch the S2000 autox, its easy for me as with most other cars. I spent two years in karting making it work for me as well. Not saying I am god but I feel like I know how to induce it.

I am used to this type of behavor from RWD:

[ame="http://www.youtube.com/watch?v=dFYAapvsFTk"]Snappy Oversteer. - YouTube[/ame]

The other thing as I said is the damn brakes on the car are inconsistent. First two runs, nothing, next few better so I feel like my braking zones are always changing. Firm pedal but no consistency in autox. Thing is I feel I am consistent, maybe not consistently lighting fast, but my times reflect consistancy, and I am at that point where I feel as they say in racing school unconsciously competent.

With the help on here I hope to get the car more where I am in a confident in it with my driving style.

Originally Posted by CSG Mike

@Dezoris your car is understeering quite a bit. I'd recommend you get QUITE a bit more camber. Start at -3.2, and don't lower the car too much.

As for the brakes, try altering your seating position to be 1 or 2 notches closer to the pedals and steering wheel.

I will max out the front hopefully this week and post back. Seat is almost maxed out towards wheel I can maybe get one more click before knees are jammed up.

I also have 1/16 toe in rear I will eliminate.


Thanks guys.