New Front End Alignment - Not what I was hoping for

[jgkurz]

Hi All, I need some perspective on my front end alignment. I recently installed adjustable lower control arms and TC rods and got the car aligned with specs I thought would be more suitable for track days at my local road racing venue. I don't think my specs are radical by any means, but after the alignment the steering is harder to turn and dull. I went with slight toe-in to avoiding tram-lining aka wandering on the freeway. 0.06 deg toe-in on each side = 1/38" so very slight.  I have all the typical novice suspension upgrades including bump steer spacers, quick ratio steering arms, and urethane everywhere. My tires are 225/50-16 and 245/45-16. I also have lowering springs and Tokico adj struts that bring the car down about 1.5" from stock. My front sway bar is a Suspension Techniques 1-1/8" with the typical urethane bushings. Before the upgrade the two frame mounts for the sway bar were super tight and near locked. To resolve I shimmed the mounts so the bar moves freely now but without play. The previous alignment with the stock LCAs and TCs seemed to be sharper and more responsive which is disappointing considering the upgrades I just added. Maybe the sway bar moving properly softened up the suspension which caused my previous setup to be artificially stiff and more responsive albeit incorrectly? I'm just guessing at this point. 

 

My question. Is the more difficult and dull steering feel to be expected with the additional caster and neg camber?  Are there any glaring issues that would be causing these symptoms? 

 

 

 

 

 

 

Edited July 24, 2018 by jgkurz

[LLave]

No direct tech to add, however I did save this snippet from the great John Coffey 

 

 

""

I get this question daily. Assuming you've spent money and time building adjustability into your suspension AND are willing actually adjust then these recommendations make sense. Otherwise, take the car to Pep Boys, tell the tech to "Make it all green", and hope your tires last a long time. 

Track/Autocross

For 225 to 245 width radial DOT tires try these alignment settings:
Front

Camber: 3 to 3.25 neg
Caster: 6 to 7 positive (even on both sides)
Toe: 1/8" to 3/16" out
Ride height: 5 1/2" to 6" measured at the front of the rocker outboard of the pinch weld seam.

Rear

Camber: 2.5 to 3 neg
Toe: 1/16" to 1/8" in
Ride height: 5 3/4" to 6 1/4" measured at the front of the rocker outboard of the pinch weld seam.

For tire widths over 245 try these alignment settings:

Front

Camber: 2.75 to 3 neg
Caster: 6 to 7 positive (even on both sides)
Toe: 1/16" to 1/8"" out
Ride height: 6" to 6 1/2" measured at the front of the rocker outboard of the pinch weld seam.

Rear

Camber: 2.25 to 2.5 neg
Toe: 1/16" to 1/8" in
Ride height: 6 1/4" to 6 3/4" measured at the front of the rocker outboard of the pinch weld seam.

Street

For 225 to 245 width radial DOT tires try these alignment settings:

Front

Camber: 1.25 to 1.5 neg
Caster: 4 to 5 positive (even on both sides)
Toe: 1/16" out or 0
Ride height: 6" to 6 1/2" measured at the front of the rocker outboard of the pinch weld seam.

Rear

Camber: 1.25 to 1.5 neg
Toe: 1/16" to 1/8" in
Ride height: 6 1/2" to 7" measured at the front of the rocker outboard of the pinch weld seam.

For tire widths over 245 try these alignment settings:

Front

Camber: 1.25 to 1.5 neg
Caster: 4 to 5 positive (even on both sides)
Toe: 1/16" out or 0
Ride height: 6 1/2" to 7" measured at the front of the rocker outboard of the pinch weld seam.

Rear

Camber: 1.25 to 1.5 neg
Toe: 1/16" to 1/8" in
Ride height: 7" to 7 1/2" measured at the front of the rocker outboard of the pinch weld seam.

Caveat Emptor: These are starting points for you and your car. Be ready and willing to change them based on your preferences and local conditions. These alignment settings might be a bit tricky in the rain and even trickier in snow or ice. Your tires will wear a bit faster then the stock alignment settings. If that's a concern of yours, stay with the stock numbers and don't ask me dumb quesiton like, "Well... how much faster will they wear?" or "How many miles will the tires last with the Track alignment setting?" If you're asking those questions you shouldn't be reading this thread. Go buy a Honda...  "" 

[jgkurz]

Thank you LLave. I have read John Coffey's post which was the starting point for my alignment. I just didn't end up liking the end result. Certainly my car is the issue so I'm curious what to try if I modify the car and align again.

[trackzpeed]

Increasing castor typically increases steering effort but the wheel will “unwind” easier. Negative camber should give you less understeer but not necessarily sharper turn in..... you may need a rear sway bar to offset the front.... my experience has been to much front bar makes the car push.  Keep in mind my car is an LS swap so torque and power allow me throttle control quite a bit more than when I ran the L24.  There is a definite science behind it all but driving at the limit by what you feel is best for me. HTH. JIM

PS: I used coffees suggestions as a base for suspension tuning. 

Edited July 24, 2018 by trackzpeed

[JMortensen]

Not seeing anything that would cause a dead feeling in the wheel, but IMO that alignment is short on neg camber in front and heavy on toe in in the back for track use. 

I am not a fan of the 1 1/8" bars, would swap for 1" if I were you. You don't mention a rear bar, but with lowering springs I would run a 1" front and the ST rear bar that attaches to the uprights, and then shim it back 1/2 to 1", whatever fits best. 

Removing stiction from the sway bar bushing may make the suspension less stiff, but it also makes it smoother which means that the sway bar will resist in a constant way, rather than resist/release/resist/release, etc. When I built my suspension I went to great lengths to eliminate stiction in every way I could, as that makes the car more consistent and allows the suspension to work, and the wheels to follow the pavement better in bumpy turns.

[seattlejester]

Toe would be my only input, when I dialed all of mine out my car went from darty to a bit numb, still goes where you want it to for sure, but it used to feel like it would turn on a dime, granted as you say the downfall was I had little confidence running it straight.

[jgkurz]

2 hours ago, JMortensen said:

Not seeing anything that would cause a dead feeling in the wheel, but IMO that alignment is short on neg camber in front and heavy on toe in in the back for track use. 

I am not a fan of the 1 1/8" bars, would swap for 1" if I were you. You don't mention a rear bar, but with lowering springs I would run a 1" front and the ST rear bar that attaches to the uprights, and then shim it back 1/2 to 1", whatever fits best. 

Removing stiction from the sway bar bushing may make the suspension less stiff, but it also makes it smoother which means that the sway bar will resist in a constant way, rather than resist/release/resist/release, etc. When I built my suspension I went to great lengths to eliminate stiction in every way I could, as that makes the car more consistent and allows the suspension to work, and the wheels to follow the pavement better in bumpy turns.

 

 

Good stuff Jon. Thank you. I agree that the elimination of stiction probably is now allowing my suspension to work properly. My car does occasional street duty which is why I only went with -1.3 camber in the front. The rear control arms are all stock and non-adjustable so I'm stuck with those specs until I upgrade. I probably now also need stiffer springs to dial in the car. For the rear sway bay, I use a 3/4" 240z style rear bar mounted to the uprights. My 280z bar rubbed my CV boots so I switched styles.

 

What do you mean by "shim it back 1/2 to 1", whatever fits best."?

 

 

 

 

Edited July 24, 2018 by jgkurz

[JMortensen]

The bar ends wind up forward of the control arm holes. Shimming the bushings back from the uprights fixes this. 

[Leon]

That's a lot of rear toe. I would dial that back to no more than 0.10° per side. Do you have your previous alignment specs to compare to?

[jgkurz]

4 hours ago, Leon said:

That's a lot of rear toe. I would dial that back to no more than 0.10° per side. Do you have your previous alignment specs to compare to?

 

 

Yeah, I need to get the rear alignment sorted out. I also should go to coil overs, stiffer springs, camber plates, 1in front sway, and adjustable rear LCA's. 😫 

 

After reading all your responses and talking to some experts I think the car is acting properly. The additional steering effort is a combination of the quick ratio steering arms and the extra caster. The dull steering is probably because the suspension is actually working now and not artificially stiffened by the sway bar stiction. 

 

Below is the old alignment where the front sway bar was too tight. 

 

[Leon]

Strange, I wouldn't expect steering feel to dull after increasing caster/trail.

 

It comes down to what you mean by dull steering feel. Is it the steering feedback that's dull or a lack of body rotation per steering input? To me, it sounds like the latter and should be helped by reducing your rear toe. A huge front bar and no rear also doesn't help.

[jgkurz]

11 minutes ago, Leon said:

Strange, I wouldn't expect steering feel to dull after increasing caster/trail.

 

It comes down to what you mean by dull steering feel. Is it the steering feedback that's dull or a lack of body rotation per steering input? To me, it sounds like the latter and should be helped by reducing your rear toe. A huge front bar and no rear also doesn't help.

 

Leon, thank you for the comments. I drove the car again tonight. The return to center is worse as well so that's another symptom. It's a little darty if that makes sense. It's slight but noticeable. I think the combination of  additional steering effort + lack of RTC + dartyness make the car less fun to drive. It may be better at the track but it's a hotmess on the street. I may go back to stock caster and add a bit more toe-in and see if that helps. 1/40" toe-in is probably not enough. I can't fix the rear alignment until I get adj LCA's. 

 

I do have a 3/4" rear bar. I should have included that in my first post.

[Leon]

Higher caster should have more of a centering effect due to the increased trail which increases the aligning moment on the tire. The caveat is that with the steering geometry of the Z (including but not limited to), there's a point where steering forces reverse and there is a wind-on effect where the wheel steers itself towards lock. This is all a long-winded way of saying that bringing caster back down will not improve your return to center problem and that return to center will suck no matter what, when you reach a certain critical steering angle. However, I haven't studied the Z's geometry that carefully so I very well could have overlooked something.

 

Adding more front toe will make the car dartier, that looks good where it is. The added negative camber may make the car dart a bit more but it's a smaller effect than toe.

 

I really think that rear toe is doing you wrong plus maybe some other mechanical factor that we haven't found yet. Have you checked your steering system for slop (ball joints, rack, etc.)?

[HuD 91gt]

A bit of a tangent, but you bring up your sway bar was too tight. I’ve yet to read a proper way to tighten sway bar bushings.

[jgkurz]

5 hours ago, HuD 91gt said:

A bit of a tangent, but you bring up your sway bar was too tight. I’ve yet to read a proper way to tighten sway bar bushings.

 

The bar should rotate smoothly in the frame bushings. It should not catch or have stiction at any point. I added shims to each mount so when I tightened the bolts, the urethane clamped the bar snuggly but no so tight the bar could not move. I also used a lubricant meant for sway bar bushings. 

[jgkurz]

8 hours ago, Leon said:

Higher caster should have more of a centering effect due to the increased trail which increases the aligning moment on the tire. The caveat is that with the steering geometry of the Z (including but not limited to), there's a point where steering forces reverse and there is a wind-on effect where the wheel steers itself towards lock. This is all a long-winded way of saying that bringing caster back down will not improve your return to center problem and that return to center will suck no matter what, when you reach a certain critical steering angle. However, I haven't studied the Z's geometry that carefully so I very well could have overlooked something.

 

Adding more front toe will make the car dartier, that looks good where it is. The added negative camber may make the car dart a bit more but it's a smaller effect than toe.

 

I really think that rear toe is doing you wrong plus maybe some other mechanical factor that we haven't found yet. Have you checked your steering system for slop (ball joints, rack, etc.)?

 

I have checked the car thoroughly but I could have missed something. If a better mount or bushing was available I have upgraded it. 

 

Back to the toe conversation. My understanding is the toe-out in the front would cause more dartiness but better turn-in at the track. Toe-in minimizes the dartiness/tramlining affect especially on the freeway. Is that not true?

 

Regarding rear toe, any suggestions on reducing toe-in with stock lower control arms? I could loosen up the mounts and try to tighten the LCA's while prying on them. 

 

 

[socorob]

What would be a good maximum caster for the Z assuming everything was adjustable, and nothing would rub or run out of thread length? I know some newer cars run fairly high caster.

[Zipper]

jgkurz - You mention 'dartiness', also lowering springs and bump steer spacers. Have you considered bump steer? Hybridz bumpsteer-faq

 

Not a suspension expert - but I experienced a big improvement in handling feel with similar mods to you after changing to adjustable tie rods. On alignment rack, toe changes were obvious by ratcheting suspension down/jacking up. Was able to tune a lot out with adjustable tie rods. Bigger tires, quick steering arms, and a smaller steering wheel contribute to heavy steering feel.

[jgkurz]

29 minutes ago, Zipper said:

jgkurz - You mention 'dartiness', also lowering springs and bump steer spacers. Have you considered bump steer? Hybridz bumpsteer-faq

 

Not a suspension expert - but I experienced a big improvement in handling feel with similar mods to you after changing to adjustable tie rods. On alignment rack, toe changes were obvious by ratcheting suspension down/jacking up. Was able to tune a lot out with adjustable tie rods. Bigger tires, quick steering arms, and a smaller steering wheel contribute to heavy steering feel.

 

 

Do you have a link to the adjustable tie-rod ends you used? 

[socorob]

Techno Toy Tuning or Apex Engineered have the tie rods. I got TTT to make mine longer so I could get as much camber as I would ever want. With the stock tie rod ends, I could barely get -1.5 camber with just maybe 1/2" threads left in the tie rods. I wasn't comfortable with such little engagement so I got the others and had them made longer. I'm sure apex would probably do the same if you ask.