I just want to say my front end would be perfectly aligned if I didn't adjust the left tie rod precisely the amount I needed to in the opposite direction. :bonk:

It's fine, the rear still needs work. Up we go again...

That's so yesterday. The Tootsie Roll system is much tastier.

Hey, that sounds like me! I learned precision errors from my dad.

Lol. I took a course in grad school taught by a famous statistician who swore he’d fail any student who included a regression coefficient taken to more than 1 digit to the right of the decimal in a paper. I can still hear him 40 years later.

“Why in hell would you publish a coefficient like 2.546, when you know damn well your measurement model is only good for +\- 4 percent. Even saying it’s 2.5 is false precision.”

Agreed! Similar situation for me and a physics professor for whom I eventually worked. "Two decimal places is more than enough for the real world."

People have forgotten about slide rules too.

Finally went for a drive (to pick up some lunch at least) in the FRS today, did not crash.

First reaction:. :D :bellyroll: :happyanim:

The only way to describe the handling without overusing the term "solid" is that before it felt like a good coil spring mattress. Now it feels like a good memory foam mattress. Didn't drive it too hard because the woods makes a bad buffer zone when I'm still learning the new suspension, but it's definitely a bit faster at WOT.

Issues I'm still working out:
-Perrin still hasn't gotten me the right sized bushings for the sway bar. It's probably fine with the shims for now, but really wish I had the right parts.
-Have about 1mm toe in to dial out in the front. Rear alignment needs some minor tweaks too, but it's real close.
-Steering doesn't self center as well as it used to.
-Need to investigate a bunch of strange sounds that are probably normal but definitely new.
-Havent done any logging on the tune to make sure everything is good for now.
-I should probably get a new lower spring perch from RCE but the oversized set screw seems to be holding up for now... (This was a bitch and a half to get in but I'll do a write up for anyone as dumb as I am who wants to try)

Woot! "Final" alignment numbers. Just in time because the first autox event is tomorrow.

I bet the rear camber fixes itself if I drop that rear left another mm but I don't want to risk throwing off toe this late. Math-wise it's really closer to .15° difference but rounding makes it look worse. Might give the front left a nudge when I put on the summer tires tonight...

April fool's came late for me. Got to autox, stft and ltft were in the high teens/ low 20s. Started thinking I had some kind of exhaust leak and went searching instead of walking the track. Found nothing (considering it's a parking lot with limited time and no jack stands) and just reflashed the tune and ran with it. On the way home, fuel trims returned to normal.

Conclusion: Tune issue or sensor issue.

Other conclusion: All the suspension stuff is fantastic. Thinking back on it, I might need to up the damping a bit next time. Or just learn to drive better.

I really do love your notes & method. Bravo!

Perrin sent me new sway bar bushings last week, but forgot the lube. Got some from Amazon and finally got around to installing them. On measuring them, the hole seems to be about 0.1mm larger in diameter, though the bushings are about 1mm taller :iono:. Definitely better than before once assembled with no shims but still a bit more resistance than I'd expect. I added a 2mm shim to the clamp on each side and called it good enough. I'll check it again after driving a bit. No pics of this one.

I do have pics of my car's new stalactite however. The sealant to plug the leak almost worked. At least I know exactly where the leak is now. On to plan B I think.

If this doesn't work, it might be off to get valve springs replaced...

Is that this?

No, it's the black stuff.

https://www.permatex.com/wp-content/...OZ-82180-1.jpg

Hmmm, is there a secret trick to not gouging out my camber plates? Asking here because the amount of people likely to tell me I'm being stupid is smaller lol.

Car is off the ground, wheels off, and I try to take pressure off the tophat when moving it.

Are there burrs on the bottom sides of those arrow washer things? Flip them over?

I think it's just a really sharp steel edge that hangs and rests on the softer plate. Probably could file it down a bit but at this point I've got the camber all set and it's already gouged.

I just read over again. The secret is to support the wheel assembly just enough to prevent it from hanging by those arrows while you scrape them across the plate. Next time, drop the car just enough for wheels to touch.


edit... wheels off... lift a little with a jack? iono but you get what I mean...

I do lift the assembly as I move it (wheels on or off), I think the little tab just hangs off the threads at a slightly downward angle. Might try a jack if I have to do it again.

I think you're right about filing. Just lift the bottoms of those arrow protrusions a smidge.

I had Vorschlag plates on my STi. I'd take the allen wrench I used on the bolts and pry inside the slot to move them. Worked well without gouging as long as the plates weren't maxed out and there wasn't room for the wrench.

Ok so I got the new alignment done, but I'm a bit perplexed by something. With the steering wheel straight, the car tracks straight. However, it pulls slightly to the right. I checked this on both sides of the road to eliminate road crown as the cause (living in south bumfuk has it's advantages). Toe is 0° to +.03° all around according to my measurements. Maybe it's time to find a professional with lasers and real time feedback?

New camber is -3° up front and -2° in back, and I dropped the rear left ~1mm so it's even ride height.

So if you take your hand off the wheel it starts veering to the right slightly?

If you drive on the other side of the road does it pull left? Could just be tramlining. It gets a lot worse with more front camber.

Yes. Kind of. It feels like it wants to center a bit to the right.

No. The rightward pull abates for the most part on the other side of the relatively steeply crowned road I was testing exactly that on, but it does not start pulling left equally. Further, the rightward pull continues off center on flatter roads, turning left requires more force than turning the same amount right.

Other things it's not:
-Imbalanced tire pressure
-my imagination (ok there's a real thing that goes here but I suddenly forgot it...)

Edit:. I remembered. It's not sway bar preload either.

Ok, so I went for a longer drive and measured again. Steering wheel definitely wants to offset to the right still, though it's less noticable at higher speeds.

Measurements indicate a slight outward toe (-.06° max) on the right front wheel, otherwise everything is on the low end of 0° to +.03°. Now, the intuitive answer is that's the problem right there, straighten out the FR and it should be good. BUT, I think I should expect the steering to want to shift leftward in this case due to the caster of the front wheels wanting to balance out. So my actual conclusion should be that adjusting the front left into line with the front right will bring the steering back to center while in motion.


However, if I adjust the FL instead of FR, then my car would theoretically be crabbing down the road at an angle of .06°, considering all my current measurements are taken with the steering wheel completely straight. The offset is indicating the car wants to crab right now for some reason, and making the adjustment would allow it to do so.

But wait, there's more! I took this thought a bit further and asked if my string box is somehow skewed relative to the body of the car. It's perfectly (+/- .25mm) parallel to the centers of the wheels, but my left rear LCA is actually extended 2 or 3 mm more than the right rear to even out camber. Measuring to the body says my string box is about .1° off the body centerline, which translates to 4.5mm difference in wheel center. The good news is that translates favorably to actually reducing crabbing relative to the car body, if I'm willing to accept that the wheels probably won't be perfectly in line.

Or I can just pull the FR toe in and see what happens...


TLDR: I'm overthinking this and still deciding what to do...

Suspension geometry, steering wheel centering, toe angles, and steering angle reset, roll center, bump travel, droop travel, bump stops, etc etc all make my brain hurt. Physically hurt.

So, I've been kinda tripped up on this in the past and maybe had some optical illusion moments, but what are you using/referencing to determine "straight"?

Because sometimes if I try to look at the way the two "forks" that point downward are oriented it doesn't feel like the wheel is "straight", so I'll look at something else like the "SCION" writing on the steering wheel badge to see if that's perfectly level/horizontal. And then I'll think "Oh, maybe it is actually straight right now"...

So yeah I don't know if during my last alignment they didn't center the wheel EXACTLY straight, or if they used a different visual reference to determine what "straight" was.

Sorry for the tangent, just curious as to visually what you're using to determine when it's perfectly straight/centered.

I use 3 measures which all coincidentally align. First is the plastic body of the wheel to the plastic housing around the steering column. The top edge of both aligns pretty closed when the wheel is straight.

Also, the vertical line straight through the center of the wheel align with anything centered in the gauge cluster when I am sitting in normal driving position.

Third, I just look forward and think go straight and let my arms tell me what is straight. Considering I've had the car for 9.5 years the muscle memory is pretty strong. The third method actually wants the wheel to be just barely offset to the left relative to the other two, but that's probably just countering road crown lol.

Here's my note to my shop after my last alignment:

Me: "I noticed that I have to have the steering wheel turned slightly to the left in order to go straight, if I put the steering wheel perfectly straight the car goes to the right slightly. Not sure why this is or if that will change when the tires break in" (I had 4 new tires installed at the same time.)

Shop: "We can definitely look into it again next time you come and do another alignment when the suspension settles, but if you want it to drive straight against the crown we will need to run more camber on the passenger side than the driver's side. Most FRS types want a symmetrical alignment so that the car turns in both directions predictably and equally. I hope that makes sense. I do not think it will change."

Soooo, that response kindof left me more confused than before I sent my inquiry/feedback, but there you have it. I have noticed it has subsided as I've put more miles onto it, or I've just gotten used to it.

Crucially, I don't notice any dramatic pulling to the right if I take my hand off the wheel, so I've just kinda said fuck it.

Edit: Attached alignment sheet for the hell of it.

I figured it would only take me an hour to try the easy way of just adjusting the front right to be not toe-out and see the results as opposed to trying to think through what would happen. Turns out that worked quite well. Steering still pulls a miniscule amount to the right, but it's much better now.

I think what was/is happening is the rear might be skewed by just a bit causing the car to want to crab to the right ever so slightly, which I still need to fix. Because of the camber I added, the front caster wasn't really helping me at that small angle and the drag from the towed out tire was pulling just a bit more to the right.

Or I'm full of shit and I don't really know what is going on lol. :iono:

Sounds like your adjustment made a noticeable and measurable improvement, nice job!

Stuff like this is always a source of stress for those of us who want everything "just so" or done to an exacting standard.

Did an exhaust leak check via soapy water method. Of course the slip fittings showed a "leak", but it appears the vband flange is also leaking. Which kind of explains why I had hot air blowing out the right side of the car after a 20 minute drive. Didn't find anything else, but it's kind of hard to get the pressure up with the slip fittings not being hot and sealed.

Tried loosening and retightening, but it's still leaking.

Sooo next step is get a new vband? Maybe this one is stretched out? Or some sort of gasket or high temp sealant?

Or a different header lol...

I also got just a few small bubbles coming out of the o2 sensor, just above it's little heat shield which was really weird...

So I tore out one of the clip nuts that tie the two undertrays together when removing them. Basically 2 of the clips have been messed up for a while, probably cross threaded at some point. One broke through the fiberglass when the bolt got stuck. I figured it would be an easy fix.

Bolts are M6-1.0 x 15mm extended point, so I got compatible clip bolts from Amazon. Specifically these: https://www.amazon.com/gp/aw/d/B0BG1...b_b_asin_title

They are actually pretty nice replacements in general and fit the space for the OEM clips if the tray isn't broken. They came with bolts that are probably too long, but I am just reusing the OEM bolts.

For the fiberglass tray fix, I just cut some scrap aluminum sheet, doubled it up with super glue, and the super glued it to the fiberglass. For future reference, it's better to glue it to the top of the original panel, rather than the bottom due to clearance issues with the clips I got (don't do it like the picture). Drilled a hole, gave it a bit of black paint because it looked weird, even though you don't actually see it on the car lol.

Put it all on the car and... I missed. :bonk: it's fine, I'll get it to work the second time around. Need to put it on the car, THEN drill the hole.

Warning, long post
 

Been suspecting something is off with my alignment methods, as the subjective feedback from driving did not match what was expected from the measurements, so I came up with a few tests.

First, the track test, made possible by my particularly deep garage. Center the steering wheel and move the car as far forward as possible. Use a straight edge/square to mark the ground at the outside edge of each rear tire. Then move it back until the front wheel is next to those marks and make another two marks. Move the car out of the way and measure the distance between marks on the left, then on the right, then subtract to get the difference. Inverse sine of that difference divided by wheelbase (2570 mm on the FRS) gets the angle. Mine showed it was off by 4.5mm, .09°.

Second, measure from the string to known points on the body. This assumes the string box is parallel to the centers of the wheels, but the wheels might not be centered on the body. Drop a vertical line off the string box at two points on the left, and again on the right, and measure the distance to 4 symmetrical points on the body. I measured to the crease in the rocker/quarter panel just behind the fender, and the edge of the rear wheel well. Subtract the front left from the rear left, ditto for the right, then subtract those results from each other to get the side to side difference. Measure the length between the measured points. Divide the difference by the length , and inverse sine the result. Behold, my result was 2mm, .05° in the same direction.

Ok, so something is clearly up. Bring it to a professional and have them measure it. Their toe numbers were precisely .09° off from mine, in the same direction as my tests indicated.

Now I'm trying to figure out what I'm doing wrong when building the string box. I'm not 2mm off each axel due to measurement inaccuracy. I'm measuring from the inside lip of the wheel mating surface (no center caps) so maybe that's inaccurate? Hard to believe that adds up to 4mm difference though...

Puzzling.

Also, my fuel trims went haywire and came back down again. My guess is that exhaust gasses from the double slip are getting caught in the O2 ambient air side and messing with it from time to time. Or my O2 sensor is broken. Maybe I need an O2 snorkel. It's definitely not having the wrong headers...

Ok quick update.

Did my 2nd autocross on the new setup. I made some changes between last and this one. Overall pretty pleased with the car, though it was damp, then wet during my runs.

New alignment figures (#30)
Front camber: -2.9°
Rear camber: -2.0°
Front toe: 0° to +0.03°
Rear toe: 0° to +0.02°

I was able to sort out the rightward pull a bit more by adjusting the rear thrust angle. Somehow my string box is off and after taking a bunch of measurements I still don't know why, but I just compensated for that while setting it up and it seems to have worked out. I think there's some minor adjustments I can make to camber, but for now it's fine.

Replaced the too-small front sway bar bushings with slightly larger diameter.

Set front bar (19mm Perrin) to stiff.

Fixed my undertray for real this time and forgot to take any pics to prove it...

I'm pretty convinced my theory regarding the o2 sensor is correct. I confirmed that at least one of the double slip fittings isn't sealing all the way when hot using a smoke stick. Also leaking on startup is bound to have some effect in there without the fans blowing. I'll deal with that eventually.

I haven't seen full results from the autocross yet but I was about 4-5 seconds off the competitive pace for STX judging by the few times I saw and my own on the timing board, which is to be expected considering I am not running competitive tires yet, and took a ride along, and left the spare in, and had a full fuel tank. I think I'll be looking for wheels and tires next if the budget allows. Might be regretting modding my house this spring...

Autocross impressions: Dry handling was well balanced I think, maybe a little sensitive at the rear but I kind of like it that way. Probably could use even more camber but I don't know how to figure that out yet. Was a bit of a handful when wet, as it rained on my last two runs. I am pretty sure I drifted the entire second to last run, though I think I somehow made all the gates without penalty. Good chance to figure out the wet limits in the new setup at least lol.

Lol that was a lot longer of an update than I anticipated.

Budget says yes. Wife says yes*. Wheels and tires are a go! :party0030::happyanim::thumbup::bow:

Now I need to figure out what to get...

*Ok she said "sure" when I wasn't able to answer her question on whether I would be more or less likely to die doing autocross with these. :iono:

The APEX racing ARC8s look great and where I plan to spend my money. I think I am just a sucker for the fact they are basically designed around our platform

The Arc-8 is the current frontrunner. Need to pick an offset though.

Please keep us posted :) I seems like 99% of people go ET42 over ET35. I was thinking ET35 myself until I saw so many people going ET42. Now I don't know haha

I sure hope I got those offsets right LOL