Spuds' Vroom Machine

[gnarjunkie]

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.

[Spuds]

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.

[Clipdat]

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

[NoHaveMSG]

Originally Posted by Spuds

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.

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.

[Spuds]

Originally Posted by Clipdat

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

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

Originally Posted by NoHaveMSG

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.

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.

[Spuds]

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...

[Clipdat]

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.

[Clipdat]

Originally Posted by Spuds

all my current measurements are taken with the steering wheel completely straight.

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.

[Spuds]

Originally Posted by Clipdat

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.

[Clipdat]

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.

[Spuds]

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.

[Clipdat]

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.

[Spuds]

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...

[Spuds]

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. it's fine, I'll get it to work the second time around. Need to put it on the car, THEN drill the hole.