Some Autox Discussion
 

Had a great weekend with my local car club at our autocross season opening. We held a school on saturday and event #1 yesterday. Was a great couple of days. Being so involved in the club earned me the right to stay after the school yesterday afternoon with a bunch of other friends/club members and just play on the course for the rest of the afternoon. We all played on the skid pad till we were dizzy and did the slaloms over and over again. We drove each other's cars and it was an absolute blast. Hopefully someone grabbed some pics!

Anyway, I learned a lot about my car's setup.

First of all, the KYB AGX's, while they suck badly, aren't really slowing me down at all. There was a huge lump in the middle of an off camber, downhill right turn that would upset cars horribley and put their dampers to the test and I was reasonably pleased with how my car took it versus the guy with the Fatcat revalved bilsteins. I really expected more from those to be honest.

Second, all you newbs need to put your rear sway bars on. I dont know how you stand it, or how I stood it for so long for that matter. I spent a LONG time playing on the skid pad trying to understand the dynamics of my car and without the sway bar I just could not induce any kind of oversteer no matter how hard I tried. I had my friend yank the e-brake and still nothing, no spin, no sliding. The understeer was so bad that it was seriously limiting my speed around the circle. I ran home and put my rear sway back on and OMG. It allowed me to go MUCH faster around the circle since it allowed me to actually throttle steer around it. The car actually rotates now and in a much more controllable way. I understand so much more now than I could possibly explain.

Third, Launch control. While I didn't use it much at the event on sunday due to its uselessness with the course design, we had a timed ~60ft launch setup at the school on saturday. Without launch control I was getting solid 2 second times and Jacki was getting solid ~2.125 second launches. Jacki's first time with launch control she got a 1.8** and so did I. After that, every single launch was in the 1.8s reliably after 15-20 more launches. If I had my laptop and could play with the settings I think we could have gotten the launch down to 1.6. While she didn't understand the fun in this, I thought it was kind of a fun game getting the same consistent launch times while everyone else tried to catch up. The WRX beat us with a 1.6**.

My biggest issue of the day was the tight slalom. My little 5'2" girlfriend had an even harder time muscling my non-power steering car around. Stock miatas with power steering where 2+ seconds faster than us (one of them on snow tires) through the course. Now, i will admit that the drivers need more work for sure, we're slow drivers, but I think a lot of it has to do with power steering, or atleast the power steering ratio. I drove a 92 stock on the course and could not believe how quickly you can toss it around cones with the better steering ratio.

I dont know where I actually stood in my class but i'm hoping not last. I probably did get last though. I got all clean runs except my last one with a big smokey spin in the skid pad. FTD went to a turbo civic on R888s, second fastest to a Volvo 240 on street tires, third to an STI on street tires. The Volvo gets mad respect, but the FWD cars (after getting a chance to drive a couple of them through the course) just make it so easy especially on R-comps. Very idiot proof.

Possibly one of the best posts I have read in a awhile, thanks for all the info!

One question:

From what I am reading, you have an actual manual rack, as opposed to a de-powered rack?

Yes, I have a standard manual rack.

I just bid on a power rack on ebay and sent a message off to lev to see what they run. This plus a front sway is probably all I will upgrade this season as I just want to improve on my driving and start getting good at playing with tire pressures.

How the hell did the Volvo set the 2nd FTD?

Great driver and a pretty well built car. There was another volvo but it was a wagon and he was pretty quick too but his car had Just been put on the ground the night before after a long winter build. He would have been faster if he wasn't actually tuning while doing runs.

I can't understand why your car won't oversteer. My STS car will still oversteer easily with a big front bar and no rear bar. Even with hoosiers (obviously not in STS at the time)

Perhaps its alignment. My car hasn't had one yet this year and is 20 years overdue for new eccentrics. But I swear that no matter how hard we tried we couldn't get it to oversteer, it felt worse than a FWD car on the skid pad.

I don't doubt that your car pushed on the skidpad without the rear bar. Fortunately, though, autocross is about more than just the skidpad. Where not having a rear bar helps most is in power application. This also happens to be the strong point in our cars, so it needs to be exploited in any way possible. Removing the rear bar is the most widely accepted way. Just like everything, there is a give and take.

Good way to put it. I found, personally, I was faster through slaloms with the rear bar because I could throttle steer it and rotate around the cones in a way that just didn't happen without the rear bar.

I concur on the agx. My car trophied in C-stock with 2 owners, 3 drivers in many different areas of texas.

Although they are truly pos but they can get you buy. I love my new set up. CG + revalved bilsteins

Yes no bar will remove over steer. Can be use to cure some problems on some cars though.

3. My car is non power anything NB. Me and my co driver practically always faster than the PS cars. Just have to react quicker and before you have even crossed a cone.

I run no rear bar, and can induce oversteer at will. This is with less than stock hp. (1.6L & 4.1 diff).

You must be running more spring than me then. I'm on FM springs.

I used to run on FM.

Results are up.

My class.
http://scorekeeper.wwscc.org/results...yclass?list=C7

Girlfriend's class.
http://scorekeeper.wwscc.org/results...yclass?list=C6

Overall list of scratch times. I was wrong about the volvo although they were still fast.
http://scorekeeper.wwscc.org/results/cscc2010/1/topraw

I think we are going to race the rest of the season in our Integra instead of the miata. We'll have a much better Pax.

Perhaps the need or lack of need for a rear bar is tied to the front vs. rear spring rates each of you is running. My RX7 was very well balanced on stock springs with FM front and rear bars. In a steady-state turn you could just add or remove throttle to change from under to oversteer. It was dead predictable and easily controllable at the limit. The next owner added very tight springs to the car and it would corner well up to a point, then snap oversteer violently. I have no spring rate data.

Well I am telling you what my experiences was. I do not mean understeer.

Has anyone ran koni race's at an autox event? If so what springrate did you run, swaybar(s), what type of diff, and how much powah?

Pondering on a new suspension setup, wondering if 750/450, f/r , will be too much and if the koni race's would have anything over the standard yellow.

Koni Race's work well with those spring rates. That's a common setup for STS and even some CSP guys.

I have that exact combination on my "90. Works very well. Using the big, hollow RB bar up front, stock bar in back. The RACE shocks are valved to handle the spring rates and are 1" shorter. The yellows are supposed to be pushing it/done at 500# rates.

If it's a DD, it's not real comfortable depending on how the roads are. Very stiff (catching air over train tracks is fun though). The setup handles both autox and track days very well.
SA

edit: actually my combo is 700/450...

I'll trade you racks?

I was going to de-power mine. How different is the ratio between the power and manual racks?


Where do you AutoX? You should come up to Pitt Meadows sometime and run up here. I wouldn't mind going south for an event or two.

I dont think you want to trade. Lets drive eachother's cars at an event and you'll see what I mean. If you really want to after that then i'll be down like a clown in a gown with an upside down frown.

I autox at the port of bellingham with the chuckanut sports car club. The port might be shutting us down though so we may not have any more. I'd love to head up into canadia to hit some events. I'm already planning on hitting the knox mountain hill climb.

My car is going to be a track car, not so much a AutoX car (although I'll still AutoX for fun). The manual rack will be great for the track. Although, with some other cars which have manual and PS racks available for the same car the manual usually is a bit of a slower rack? Gotta check that out. If they are the same we can do the swap.

My club which I help run myself is www.ubcscc.com (University Of British Columbia Sports Car Club) and there is also www.vcmc.com Vancouver chinese motorsports club... lol but %75 of the members are not chinese.

When is the next event in Bellingham?

The Pitt Meadows skid pad is about 15 minutes past the Lynden/Aldergrove border. We have a number of people from WA come up to run.

There is more to under/oversteer then just a rear sway bar. You should look into alignment, spring rates, shock settings, and tire pressures before calling out "noobs" with no sway bar. Of course, I've been racing with no sway bar for 3 years and I am intrigued by someone who calls countless other "no sway bar" drivers noobs.

Otherwise interesting thread.

No rear sway is a good budget way to set up a stock or STS car. A properly set up Miata should not need the rear bar removed to have optimal grip.

Didn't read the whole thread but try and take some caster out of your alighment to make a manual rack easier to steer.

Jeez I wasn't being super cereal.

It made a huge difference in my car. The car was much less forgiving to mistakes and sharp inputs but if you drove it on the hairy edge it was much more responsive.

The sway bar is entirely a tuning device. If you are oversteering, a quick disconnect (if you don't have an adjustable one) is a very quick fix when you are at the track. I have run without it before when I needed to depending on the design of a specific autocross course. There is not a mountain of difference between having it connected and not if your car is set up half way decently - it's a subtle increase in rear grip and squat. If your car understeers so badly you cannot possibly get it to oversteer with the rear bar disconnected, you have serious suspension issues. What many completely ignore is that what works very well for many who run similar alignments will work horribly on a car that has a different alignment. For autox and track use, there is a narrow range within which most miata guys' alignment specs fall - if yours are not similar, which would be my best guess, then that's an entirely different issue.
In terms of the power steering, you may like the power steering, but most of us don't. I have been autocrossing for 4 years and hate power steering. Sure, it takes less effort to turn, but it magnifies little inputs and makes the car more touchy, and offers less feedback to the driver. I will point out though, that the power steering rack and manual rack have different ratios. The power steering rack IIRC is a shorter ratio, so you turn it less to turn a given amount that the manual rack. For this reason, I have a power rack that is de-powered. I found when driving someone else's manual rack miata that in a slalom my arms crossed over each other and hit each other because I had to turn the wheel so far each direction so I couldn't keep my hands on 10 o'clock and 2 o'clock through that section. In mine it was just a simple back and forth steeering motion, hands didn't have to move..
-Ryan

That is exactly what i'm planning to do, depower a power rack.

And for the record, I haven't had an alignment done yet this year so i'm sure that is an issue. I will probably disconnect the rear bar for rain events still.

Alright Anton.. guess I'm keeping my rack :D...

We can have a "depower" day... lol? I have two to do. My Miata's as well as my FD's... they are very close to the same..

Ya I figured you'd want to keep it :)

I've read that there is a part you want to weld to make it as good as possible.

you're thinking of the quill shaft. It takes away a bit of play in the steering wheel or "slop"/

Yes that sounds about right.

There is an added benefit of no rear sway bar you are missing out on. Not having a rear bar allows the inside tire to maintain full droop travel on the inside tire, possibly maintaining better contact patch in certain situations.

A proper alignment is the fundamental step 1 - the beginning building block. If you don't know your alignment specs, there's no point tuning the rest of the suspension, playing with disconnecting the rear bar, messing with shock settings, nothing, because if your alignment is wack, whatever suspension setup and settings you come up with are all going to be wrong the minute you do get the car a proper performance alignment.
If you haven't done it, you have to throw out any experiences you've had with anything suspension related and how effective or not effective it was, because you were operating from an incorrect starting point.

When I added the big hollow front sway bar 4 years ago, I started understeering in the slow section. I had done an alignment recently, but one that didn't take that bar into account. I had John Stimson (sp?) drive the car, and he suggested that the current alignment wasn't capable of utilizing the improvements that the new front bar could offer. I went back and had the front camber increased from whatever it was before that, something around -1.8* to -2.2*. At the next autox front grip was worlds better, and the understeer was gone - and the car was faster than it ever had been. Just an example to show that the alignment drastically changes whether any given suspension part is going to have a positive effect or not.
-Ryan

I had an alignmnt done last season, just haven't had it checked up this season so i'm assuming its wack. Either way, I understand what you're saying.

Sorry to derail, but it is an autocross discussion...

I really really need autocross appropriate brake pads. I'm currently on Carbotech XP8 all around, FM/Wilwood prop valve, all 1.8 hardware. I have had no bite while cold issues in the past, and don't want it again. I know I should probably go with some stock/NAPA brand fronts and autocross compound rear. But I will probably be doing 1-3 track days this year, as well. I don't want to have to re-bed my Carbotechs before a track day.

Questions would be: are the Carbotech 1521 compatible with the XP8 in terms of bed-in? If so, I'm thinking I could do a 1521 front with a AX6 rear, then put in the XP8s for track days. OTOH, is there a cheaper option where I wouldn't run into compatibility problems?

For some reference and discussion, I have Satisfied Grand Sport GS pads on my wife's N/A STS classed car, and have had big cold brake no stop issues with these as well. Do not like. I need braking now!

I've got XP8s on the car right now as well for autox. Having the same issues. Just cannot get them hot enough til the very end of the run to get any good use out of them. But I fade my HPS at autox so i'm not sure what to do at this point.

Hawk HP+ perhaps?

I run hp+ on my dad's sts car. They lock-up fairly easy. I liked the hp+'s better on my car, they seemed easily to modulate, 1.8 vs 1.6 brakes?

FWIW,
I run a proportioning valve, 1.6 fronts and 1.8 rears with Axxis ultimates on the front and hawk HP+ on the rear.

Do you ever get fade on the big/fast courses? Any stopping problems when they are dead cold? Do you warm the rears on the e-brake while gridding?

XP8 is a track pad.
For autox, use properly bedded in stock pad.
I use ceramic (Bendix) pads. Good cold stops, great warm, lousy hot (track). :D
The great benefit of ceramics is little to no dust.

If you want a good all-around pad, and don't care about the dust, use "Plain Jane" semi-metallic. Autozone has Duralast for $25 per axle.

Track pads, like XP8, are for track only. Swap the rotors and pads before heading out to the track (or, better yet, right AT the track), and swap street setup before going home. This way, street rotors stay with street pads, and the two compounds shall not mix. (No, it doesn't matter if you mix the rotors).

STOP trying to figure out which pad will stop better on the autox course. Even on a 2-minute course, run on an abandoned airstrip, I've never seen the brakes even get to what could be called "luke warm".

Street pads for autox.

^^ I don't know how much it helps, but on the drive from the staging area to the line, I'll brake boost/roll brake to get some heat in the brakes and the rear tires. It seems to help with the first couple of times I stab the brakes vs. when I don't warm them up.

Well I guess i'm going to have to try some 25 dollar cheapo pads for next autox perhaps. The XP8s really aren't that bad though, they're just unpredictable when cold and like to lock up. I shouldn't be wasting them off track anyway.

Regular street pads are best for autocross. Hard braking should be seriously avoided as much as possible if you want to be fast on an autocross course anyway.

I’ve had good luck with Axxis ultimates. They are a ceramic carbon mix and seem to have good feel and the dust isn’t so corrosive as the pads with metal in them, the dust cleans up easily, and they are relatively cheap.

I have found the Carbotecs really don’t like sharing the rotor surface with any other pad compound and are a bit finicky about getting a proper bed in procedure. I have been swapping between Cobalt frictions for track however and other compounds for street and autocross use and the Cobalts just clean up the rotors and don’t leave a transfer layer behind that messes with other pads The Cobalt’s also don’t require any bed in before they just work as the rotor is relatively flat..

Bob

Regular street pads are best for autocross. Hard braking should be seriously avoided as much as possible if you want to be fast on an autocross course anyway.

I’ve had good luck with Axxis ultimates. They are a ceramic carbon mix and seem to have good feel and the dust isn’t so corrosive as the pads with metal in them, the dust cleans up easily, and they are relatively cheap.

I have found the Carbotecs really don’t like sharing the rotor surface with any other pad compound and are a bit finicky about getting a proper bed in procedure. I have been swapping between Cobalt frictions for track however and other compounds for street and autocross use and the Cobalts just clean up the rotors and don’t leave a transfer layer behind that messes with other pads The Cobalt’s also don’t require any bed in before they just work as long as the rotor is relatively flat.

Bob

I've always ran HPS on my AutoX cars. The only hard breaking is into the stop box. And the HPS with nice rotors work well. They won't fade because you're only breaking hard into the box, and then they have a chance to cool down while you're in grid.

Sorry, but I'm not a fan of the Hawk HPS for autox (Subarus, MR2s, Miatas). I really like the HP+ though. Also, FWIW, the Axxis Ultimates were good to me for my first few years of autox.

Then again, I've got a 1.8 with ABS and SS lines. Results will vary.

To each their own. I'm currently using HP+ myself.

Bob, how are those Cobalts on the track? What compounds to you use and are you running Wilwoods or stock brakes? I saw your cooling ducts, I'm going to do something very similar utilizing the ISC brake ducts.

I'm currently running axxxis ult. as well

Huh, Bob's setup maybe combined with the 1.6 fronts like Chris may be my way...Axxis Ult for autox then Cobalt for track.

Is cobalt available for single piston calipers?

One other thing that can induce big understeer is the differential. If you have a very tight diff it wants to push the front end wide when you turn in. It refuses the let the inside wheel slow down. I know my Tomei Traxx 2 way had me upping the rear swaybar from soft to medium and changing the dampers from 6/10 off full hard front/rear to 6/8. That brought me back to neutral for circuit racing.

How tight was this slalom? I go back and forth between two cars, one with a manual rack and a power rack, and honestly can hardly tell a difference. Yeah, you need to turn the wheel slightly more, but it's not any more difficult.

If you depower a power rack, then it'll just require more "muscle", but you won't have to turn the wheel as much.

I'd be more inclined to say that you're having trouble because of a balance issue, crappy springs/shocks, etc. Is your front sway bar binding? That can increase steering effort.