Alignment questions.

[utekineir]

Hi,

Sorting out details of the nc1 before making a purchase.

I see that camber is adjustable with shims. They appear to be sold individually in for $30+- in varrying thicknesses and 8 needed for an entire vehicle.

Is there any guide of how much camber change is provided by the different thickness shims?

Shims are traditional aligment item. Is there any reason why someone couldnt use regular old alignment shims rather than the fancy horseshoes?

Not against buying the oem shims, primarily just not looking to buy a bunch of useless ones.

Target offhand would be -3 or so degrees front and -2 or so rear, maybe more pending what makes the car happy, likely a little front toe out, rear 0 or slightly in. Car would see reasonably regular old airfield pavement autocross and some pleasure street driving. No commuting/dd use.

Car will likely be kept in scca solo ss class maybe an occasional tnia, scca xs class also is tempting but likely wouldn't make sense.

Thanks.

 

[chrisfrom619]

No reason why other than the oem shims are in mm and the shims we can buy local here in the states is in inches fraction. Infact one corner of my car came with the fraction shim.

 

[utekineir]

No reason why other than the oem shims are in mm and the shims we can buy local here in the states is in inches fraction. Infact one corner of my car came with the fraction shim.

Yeah, i ended up finding degree change - mm relationship, doing the math and using body shims. Track day, 20 something drag passes and over a couple hundred autocross runs, no issues.

 

[ericdc]

Would you mind sharing your findings? I am also looking to autocross mine and am interested in the best way to get to 3 degrees.

Also curious what else you have learned related to autocross.

 

[utekineir]

Would you mind sharing your findings? I am also looking to autocross mine and am interested in the best way to get to 3 degrees.

Also curious what else you have learned related to autocross.

Pretty simple, add shims to lower control arm, i had bought cheap body shims.

Your catch will be maintaining adequate bolt engagement as you add shims. 3 degrees is doable while still maintaining a full diameter of the bolt of thread engagement. The torque spec is only 40 ish ft lbs since it is into aluminum, do not overtorque. If you want longer bolts the upper strut mount bolts match the thread and spec with a bit more length, its an easy drop in. I also at one point had bought some high quality long bolts from a supply house and threaded the shoulders back further.

One big thing i did learn which took quite a while to figure out since i was aligning halfassedly at home was as you add camber the caster will also increase due to the relationship of the caster arm to knuckle. Most people consider that you cant really add too much caster with cars. That is false, I ended up with enough caster it was unloading the rear mid corner, car became much more settled after that. The added stress also ruined a control arm bushing.

Unhooking the rsb may be something that suits your surface/driving style.

This year had a lot of transitions for me in terms of figuring out sorting the car. By the end of season I'm pretty happy with where it is at. Now running light xa prep, but still on oem wheels and narrow tires. I had bought a couple years worth of clearance re71rs on tire rack when they existed. Running the small tires will be slower, but at under $600 a set i could care less. On lacking width tires it still pulled a couple points wins with clubs, bunch of raw/pax ftd and a cash shootout while being a blast every day.

Next year it likely will have one set of good tires, but mostly be run on the narrow stones, just need to set up around them better. I have a 2017 rsb that I may put on instead of the oem 2019 rate rsb currently there. Having no rsb overall has been an improvement for my uses, but i do suffer from some push with the skinny fronts. Before unhooking the rsb i had run as much as 5/8 rear toe in to stabilize the car on the older pavement i primarily run on, I was happy to get away from that extreme toe. I also have been considering reducing camber and adding some caster back, at the time i discovered the issue i just spun both caster eccentrics to minimum, the front end felt really good when the caster issue existed, just the rear was trash.

The car has been running xa for a bit now. Kw height adjustable springs spun up as high as they can go were bought because it was linear rate 30% over stock. I wanted more stiffness in front. A 72" suction cup wing, plywood front splitter that had determined it wants to be very narrow with how it has rubbed away.

Overall really happy. Its still a nicer street car than event car, having it be fun and capable on track and events is just a bonus.


Tldr, go have some fun. But if you want to buy a car specifically to autocross with just build or buy an str nd miata.