First of all, I'm in BS.

The only major mod I've done with the car is R compound tires on OEM wheels. I'm currently using the Victoracer 225f/245r combo and I'm starting to learn its limits. I feel that the tire's full grip potential hasn't been met since I've noticed (after 3 months of wear) that I'm wearing out the outer edges of the tires which seems to indicate that I need more negative camber to maximize the benefits.

I noticed that the fronts have a firm grip in tight sections but the rear end tends to "wanna come around" in proportion to the driving applied. I've tried experimenting with numerous ideas, trying to compensate for the active rear by altering my lines, entry and exit speeds. All of the results ended up with higher times, therefore I've found that the fastest way to drive on our local course is to drive it in a manner that's borderline unstable.

I've ordered the Saner front bar as I hear that's something I should've done especially with the tires I'm currently using. I'd also like to go with a more effective alignment on my car, but since my S is daily driven, my question is...

1. What alignment specs should I look into (I don't really like extra steering effort due to increases in caster, but I'd deal with it if it can't be helped)

2. Is there an easy way to alter the alignment from autocross specs to normal specs without taking the car into a shop each time? (I realize that this may be a stupid question) Sorry, but I can't see myself taking my car into a shop 12 times a year. Can I mark off the different positions of the eccentric bolt to go from normal to autocross specs?

Thanks in advance.

 

The Saner bar should help noticeably. However, even with that bar you still lack the rear traction that we'd all like. Adding camber is a good thing to do but I doubt you're gonna like the additional wear, based on what you've said.

It's not caster that you need to adjust - stock caster (6.0 deg.) is fine. Camber can be set to UK specs which adds 0.5 deg. of additional negative camber to each wheel (-1.0 front, -2.0 rear). The wear increase is noticeable but could be handled by flipping the tire over with half the tread gone and running it on the other side of the car. That's a one-time adjustment. The more aggressive autocrossers use something on the order of -1.5 front, -2.5 rear (I've seen several variations around the exact settings - YMMV). Also, use 0 toe front and consider 1/4" toe-in for the rear - perhaps more.

I use the UK settings with the Comptech adjustable bar. While I'm certainly not the fastest guy around, it works well as a compromise between street and autocross. When the season is done, I revert back to street settings to get a little more life out of the street tires. 2 alignments a year is reasonable for me.

That brings up a point I've always wondered about - do you guys who run National events check/set alignment per event or at least frequently or do you treat it as a "set-and-forget" item?

 

You'll find widely varying responses on this one. I know some guys that are on the rack nearly every week and others that check the alignment 1/year at the most. Some don't even use a rack, and do string and tape measure alignments in the garage or at an event site. Being a test & development engineer, I always want equipment that gives the most accurate results, even if it doesn't really matter.

I personally, had my car on an alignment rack 3 times this year. Once in spring, once a few weeks before Nationals (allow time to run 1 or more local events to make sure the alignment didn't get screwed up), and once in October after I put a pair of new front lower control arms on.

The last one I normally wouldn't have done, but I decided that 3 changes would be enough variables next spring and didn't need to introduce another - new Hoosier design, revalved shocks, and rusty driver.

As for Hyper-X's original questions:
-a stiff front bar will take you light years in calming down the rear end. You'll probably even think the car now understeers too much, since you're so used to the oversteer. Some rear toe-in should also help (that said, I use a solid center tube Gendron bar and only run 0.14" total rear toe in).

-I wouldn't bother trying to tweak your alignment between street & auto-x, unless you want to spend a lot of time on it (level the car, find the body center line, set up jack stands with string parallel to center line, set camber using a level and rule, set toe using the string and a rule, and on the rear, iterate camber and toe adjustments a few times because they are interrelated). If you just marked the eccentrics, you may get close, but more than likely the toe will always end up off and you won't have a centered steering wheel when driving straight.


Steve

 

Steve - why new front lower arms?

 

If it was the same reason as mine, it was due to the camber adjustment bolt being frozen in the bushing, making alignment impossible. So far, I've only had to replace the left one but I was told recently when I had the street alignment done that it would be a good idea next time around to remove the bolts on all 4 wheels and lubricate them since they're sticking a bit...

 

Long story short -
The rear LCA bushings went away, and the only way to get them is an entire control arm.

Detail -
About a month after Nationals, I drove the car on the street for the first time. I noticed I had the wheel quite a bit to the right to drive straight. My first thought was that the toe had simply drifted out. I thought a bit more about it, and how my toe has never drifted on this car, and decided I must have broke something.

It took about 30 secs to see that the left side rear LCA bushing (caster bushing for lack of a better term) was not centered about the vertical bolt that locates it. Closer inspection revealed the rubber had torn, over lots of very hard braking cycles. I have no idea when, exactly, it tore. The right side bushing showed signs of the failure starting, but was still nearly centered on the bolt. I replaced it too.

So, the arm rotates back about the front bushing, looses a lot of caster, a bit of camber, and takes the wheel toward toe out (and thus having to steer to the right). It looks like this will be about an every 2 year replacement cycle. It showed up in my alignments over time too...lost about 0.1

 

Thanks! (putting this on his to-do list over the winter)

 

Indeed! Thanks for the info! I'll be checking this in the next day or so.

I take it the tear in the rubber bushing was visible with out having to remove the lower A-Arm?

 

[QUOTE]Originally posted by davepk
Indeed! Thanks for the info!

 

Thanks, I look forward to the pics.

I put the car up on stands and got underneath to take a look and as far as i can tell the bushing looks centered. Just to verify, we are talking about the rearmost bushing of the rear lower A-Arm, correct?