Rear sway bar

[svono50]

Shoe polish is a good tool for reading how much your tire is rolling over. Short of having a tire pyrometer it is one of the only ways to 'tune' your tire pressure. I am sure Gene will have some input here. I have gotten to the point where I can read the tread shoulder pattern well enough to determine if my tire pressure needs to go up/down. Take the comments by that other racer with an objective eye, since he may be running r-comp tires or even slicks as a 2 second swing on an auto-x course is HUGE. Only mimic others that have similar tires and/or setups...which unfortunately usually doesn't exist any more with our cars.

Glad to hear you had a good time and noticed the results of your work. Stiffening up the front struts should bring the car back closer to neutral from your current oversteering, but you will have to play with things to see how it works. Note that our strut/shock adjustment is only in rebound/extension and not bump/compression, so making the front shocks firmer will basically limit the inside front tire on the turn resist pulling up and slow the car's transition down a bit. Some folks say that compression naturally increases slightly with an increase in the firmness adjustment, but only marginally from all I have read.

I have to question that your Sportline springs are actually progressive rate. When I spoke with Eibach's tech support line rep for a good hour or so a few years ago when I was researching springs, he stated that the Sportline springs were actually linear rate. Even the current video lists them as progressive, but I would have to take a tech line rep as knowing the product technical specs better than the marketing info. Now, I guess things could have changed between 2011 and now, but that would be a big shift to do with a product line...interesting. Here is the thread where I posted the spring info I dug up from the Mfg's back then:

http://www.svoca.com/forum/showthrea...ch-spring-info

[gbeaird]

First off: How did you get -2-deg camber??? I haven't read the full thread, so I may have missed something. That's great! I used to dream of -1-deg in our SVO, but we ran in the stock classes, so options weren't as good.

Eric's and Ted's suggestion on shoe polish or tire chalk can help, and it's cheap. Depending on how aggressive the surface of your autocross venue is, you may be able to see how much, if any roll-over you are getting without any marks, but if not, the markers can help.

I, too, would stiffen the front shocks a bit to help reduce the oversteer. If you can control it, though, that's better than understeer in an autocross environment. A larger front bar will help that, too.

We measure the tire tread surface temps during events. We use an infrared pyrometer, one of the cheap, Harbor Freight ones with a laser pointer. For autocross, it's acceptable although not as good as a temperature probe. Runs and forces on the tire are quicker more extreme than road racing, and usually your return from the course to grid is not that long, giving you an opportunity to measure at least some of the heat that's in the tread. It's certainly not as expensive as a temperature probe, either, so you'll need to think about how much you care about this stuff. With the pyrometer, you can measure across the tread of the tire to see how it's working. With -2-deg camber, the inside area of the tread will tend to be warmer, but you can use the temps across the surface to adjust the pressures. Depending on alignment and how aggressive the track surface is, you'll want to try to get the temps as equal as possible across the tread surface, inside, middle and outside. You'll also be able to correlate temps with how the car feels. And don't loose sight of how the car feels, no matter what the temps and rubbing on the sidewalls are telling you. Different tires behave very differently, so one with scuff marks far up the sidewall may handle better than one with the temperature that's way up in the middle of the tread, and visa-versa, so note what you see, and what you measure, and how things feel.

Take notes, so you remember from event-to-event. I've used the back of the course map, a notebook, Newton, iPhone, iPad to record my thoughts and findings. It helps a lot, IMHO.

[strangesvo]

Well I guess you caught me.... I don't exactly know how much neg chamber I have, I said about -2 degrees. I installed a chamber adjustment bolt on the strut mount to the spindle. Thanks for all the advice. Last year when I started autocrossing I went into it with small ugrades to my car and work on my driving skill. This year I will continue the same and I think by next year I will have all my major improvements complete on the car. I will start getting serious with trying to compete i.e. tire temp and psi etc. The cars that attend the delta SCCA region are not highly modified and there are only a few really exceptional drivers. Everyone else is just bringing out their stock cars. This year I moved to SM class to have a few people to race against. Everyone that used to be in ESP moved to CAM so there isn't anyone to race against in ESP. So I am at a disadvantage in SM to begin with but to be honest I'm only a few hundereds behind a few guys in the class. The fastest guy in SM is about 3 seconds ahead of me. I think I can make up a couple seconds soon but don't know about 3 or 4.

[SVOeric]

with him 3 secs in front of you, he's either getting some serious power to the ground in a hurry (which is possible in SM) or he's a master driver.
If this group changes up their courses often, and he's 3 secs ahead of you on every one, I'd say it's more driver than car. Changes in courses can negate car difference
I run with a bunch of miata's, so NO open courses, everything is tight and technical, which is a serious disadvantage for mustangs.

[svono50]

As for camber capability, I used to get almost a full -3 deg with the stock springs/suspension. When I put in the Eibach Pro's I could get a max of -0.8 deg, so I put in the MM plates and it only brought me to -1.4 deg. This past summer I performed the slotted strut trick and now hit a max of -2.0 deg, which seems to agree with my tire grip level a bit better and is giving me a much better wear pattern on the fronts. For street driving I run -1.5 deg and just tweak it to -2.0 deg for auto-x or track days.

As for your auto-x class, I seem to see the same thing around me for disparity between myself and the 'real' competitors. I only run 1-2 local events, so I am just out for fun and not really competing against anyone other than myself. The guys the really dial in their cars to the particular class would be tough to beat unless you put forth a similar effort. Keeping logs and observations are very valuable if you plan on participating on a regular basis. Gene is a good resource for info, as I believe he has a lengthy record in the SCCA ranks down in his region (right Gene?).

[strangesvo]

The guy winning SM class is driving an all wheel drive impreza witu DOT race tires so he is putting the power to the ground. I dont think he's that good of a driver. However I think I can get close to him, the club here sets fast open courses more often then tight technical courses. I also have more suspension improvements to make and plan on mounting some race tires too. The club here holds an event every month so plenty of time to improve. Plus if I didn't autocross I would hardly drive my car so I'm glad to have a club so close to where I live. Yes I drive my car to work but I live 1 mile away so the car doesn't even warm up.

[SVOeric]

lol know the feeling, the guy that used the beat me in SM drove an AWD Audi on race tires. I got to where I was .2 secs off his times (on street tires) , and he even told he he was scared I was going to knock him off the throne, but that was nearly 6 years ago, and I've not done an auto-x even that wasn't at an SVO reunion in about 5 years.

anyway, but it can be done!! Chase him down!

[gbeaird]

If you can see the tire tilt, then you are probably in the -1.5-2 degree range, for sure. The camber bolt will help a lot. Running our car in stock trim really limited what we could do. At one location, with very aggressive concrete, we corded the outside tread of a set of Goodyear street tires in 5000 miles. =8-0

The only other class other than G Street I think the SVO would be competitive would be in C Prepared (where we run now, but in a different car). That's serious involvement, though, and the car would have to be gutted, cut up some to be competitive. Still, it gets a good weight break, and can make some decent HP in C Prepared trim. I'd think of doing that to some wrecked SVO I found, but we're having a ton of fun with the other car (and have shoveled a TON of money into it already).

I DO plan to bring the SVO out and put it on course when we get the restomod completed. It would be very interesting to see how it runs and handles with the shiny new bits we've put on it. Probably on a set of Hoosier A6's on the stock rims.

Good DOT-R tires can make up a lot of that 3-second gap. Still, though, you ARE competing against a AWD car, and probably a 'boost buggy', a STi in Impresa clothing. I wouldn't be surprised. You have a good target, though, and the closer you get, the more scared he'll be when that '4-cylinder Mustang' is crawling down his tailpipe. :-)

SM does offer some options for mods, but it depends on how much prep you want to spend.

[gbeaird]

As for camber capability, I used to get almost a full -3 deg with the stock springs/suspension. When I put in the Eibach Pro's I could get a max of -0.8 deg, so I put in the MM plates and it only brought me to -1.4 deg. This past summer I performed the slotted strut trick and now hit a max of -2.0 deg, which seems to agree with my tire grip level a bit better and is giving me a much better wear pattern on the fronts. For street driving I run -1.5 deg and just tweak it to -2.0 deg for auto-x or track days.

As for your auto-x class, I seem to see the same thing around me for disparity between myself and the 'real' competitors. I only run 1-2 local events, so I am just out for fun and not really competing against anyone other than myself. The guys the really dial in their cars to the particular class would be tough to beat unless you put forth a similar effort. Keeping logs and observations are very valuable if you plan on participating on a regular basis. Gene is a good resource for info, as I believe he has a lengthy record in the SCCA ranks down in his region (right Gene?).

I think I was only able to get about -.5 deg. That was with pushing the onion heads inward as far as they would go, and pushing the spindle inward where it attaches to the strut and tightening the bolts back up. We ran G Stock, so I couldn't slot the bolt holes.

As long as I've been autocrossing, one would think I was better than am. :-) I did pick up my 2015 C Prepared Regional championship trophy and jacket yesterday, but the competition last year was kind of light. My closest competitor was my co-driver, and she couldn't make all the events. But, to finish first, first you must finish. :-)

[Bruce]

I bought new POTENZA'S and they exposed issues. I had my inside rear wheel lifting on the tightest corner-what a weird feeling. Guess I still have some work to do.

[svono50]

Bruce, you still running all (4) rear arms? If so, they ARE fighting your watts link, trust me on this.

When I swapped over to the Maximum Motorsports rear lowers and Wolfe Racing upper spherical uppers I removed the springs and swaybar and articulated the rear axle by hand. The pivot arcs of the rear uppers and watts do not agree and cause a serious bind when cornering. This will give you a false high rear roll rate and tend to lift the inside rear. The issue with removing one of the upper arms is that the rear roll rate drops dramatically and you will likely have an imbalance roll rate front/rear and go back to an under steering handling car. I just received new rear springs from MM to see if their higher rate will bring things back in line with the front and bring me back to a more 'neutral' feel. MM offers higher rate rear springs for cars running their torque arm. The lighter of the two spring rates is what the MM tech felt was a better match to my Eibach Pro fronts. For reference the Eibach Pro rears are 200-251 lbs and the MM rears are 375-440 lbs, so a decent jump up in rate. It will be a couple weeks till I get them in the car and bring it out of hibernation for me to give an initial impression of them. I will be track testing them on June 6th and can then give a more detailed evaluation.

[Bruce]

So you got big time push from taking the upper arm off? That is disappointing as the car felt almost perfect with all 4 till I hit the tightest corner. That sounds pretty stiff, let me know how it works

[svono50]

The push wasn't 'huge', but it was a noticeable shift from the previously neutral demeanor. With all (4) arms the inside rear lift was very noticeable on at least half the turns on the Autobahn as I would end up having to back off the throttle on corner exit to prevent from roasting the inside rear. With the PM3L setup mid-corner to exit grip was much improved, enough to where I could power out of the turns pretty hard, but the body roll was the first evidence that the rear suspension was no longer binding. As I pushed harder in the turns it tended to push the front enough to noticeably show up in the tread wear pattern, even with the added negative camber. Overall grip was up, but it was imbalanced onto the front outside tire.

[Bruce]

We have a test and tune on May 8th, I guess I will find out then.

[svono50]

We have a test and tune on May 8th, I guess I will find out then.

Looking forward to hearing what you notice and your thoughts.