Have a '16 Z51 M7 coupe, non-magride. Stock except for Z06/magride swaybar. Has about 13,xxx mile, tire wear looks good, no handling problems. I want to get a little more aggressive alignment that won't kill my tire wear because I put on quite a few street miles. I

I looked at the PFADT specs and have decided to try: Front camber - .8 caster 8.0, toe -1/32 0.08 Rear camber - .5 caster 0 toe -1/32 0.08

I can tweek the toe myself if I start getting excessive tire scrub.

Any recommendations/suggestions? I found a dealer that has a castor tool. The service manager is a Corvette guy. What should I expect to pay since this won't require removing washers?

 

I consider that a very mild street alignment - not aggressive at all!!

I have no idea what it will cost.

However.....just be aware of the note at the top of the Pfadt alignment sheets, and make sure your shop knows that you want TOE-IN!!

The Pfadt +/- signs for alignment reverse the signs that are used on most all alignment machines. Here's an excerpt from that note:



Make sure they know exactly what you want your rear caster to be. GM specs are very wide, and you might end up with something unacceptable if the caster is just "set to specs".

I see you say you want 0.0° of rear caster, but as you've probably seen here on the forum, a positive rear caster seems to work very well - for both street and track. I'd suggest +0.8° for rear caster - that's within the GM spec, and just make sure both sides are the same.

As far as front caster, MHO is that front caster is not critical, so I pretty much put up with whatever it is after adjusting the camber and toe. Shops generally set up front caster with a little less on the left to counter the right pull/drift due to road crowns. If you're setting up for the track, maybe you want a 0.0° cross-caster.

Bottom line - the most important thing if you hand them a printout of Pfadt specs and tell them "align to these specs", you MUST tell them you want TOE-IN because the negative sign in front of the Pfadt specs is opposite of what most shops and machines consider toe-in.

And....as far as tweeking toe yourself, yes it's very easy - UP FRONT! But I think you'll find the rear to be a real PITA with that eccentric toe-link. And it may throw off your camber and caster when you adjust that rear toe-link.

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Great! That's what I'm looking for.

 

BEZ06, help me out as you were active in that suspension thread discussing the +0.8 caster. Wasn't he recommending a touch of toe out at each end? Due to the toe curve going negative on the loaded side? Frankly I can't find a link to the thread.

I recall the Pfadt settings were done in C6 time so C7s apparently have a different design.

Here is the link. https://www.corvetteforum.com/forums...ar-caster.html

 

The specs from that other post look good(quoted above). But that camber is aggressive for the street. You can go any where between those values (-2.0/-1.7) and the stock z51 settings, as long as you keep the rear camber in proportion to the front. With toe, I would keep the polarity (negative) and proportion with the rear.

What really matters is geometry (rear castor spec sounds important to fix), and camber(typical for all cars, just a matter of how much and wear) because that controls how much tire is on the ground in corners. But it increases wear, and probably braking traction. My stock 2002 Z06 (~-1/-0.8) wasn't too hard on tires, and handled nice.

But, unless someone who really knows sway bars told you to get a MRS Z06 sway bar, take it off and put the stock one back on.
The MRS bars are soft, for the soft mode. It uses the damping to replace bar stiffness in track mode. I don't know, maybe it's just a bit stiffer than a stock z51 bar, but the Z51 MRS bars are from all the conversations I've seen are a lot softer than non-MRS Z51 cars.

 

Yes - I commented in there that I have NEVER heard of anyone recommend toe-out in the rear!!!

Often track hounds will align with a little toe-out up front for a more sporty turn-in.

However, everybody runs toe-in for the rear for better stability when accelerating out of turns.

At least - that's the way it used to be!!!

As forum member rikhek explains in post# 4 in that thread you put up a link to, those alignment specs are from Mike Levitas at TPC Racing (and DSCSport.com).

Apparently Mike has done a lot of analysis of the toe curve (bump steer) as rear caster spec is changed, and has determined that, as I understand it, that with his specs there is toe-in under compression that brings the rear toe to what you would normally want when tracking out of turns.

The -0.5mm is a very, very small toe-out. 1/2 a millimeter is about 1/50th of an inch, so it's not much at all. I believe there are a couple of track hounds that have been using it, and I haven't heard anything negative about their results.

But, I find the most interesting thing about the Mike/TPC specs is the positive rear caster. In that thread he recommends +0.8° to +1.0° caster. That positive caster has the top of the shock leaning back. Some of the track hounds have even been using a lot more positive rear caster than that (I think up to +2.0°) with good results. This positive rear caster apparently really helps to settle the rear, and especially any tendency to "snap oversteer".

The GM spec for rear caster is 0.0° +/- 0.8°, so +0.8° would be within GM/Chevy specs, so go greater than that only if you want to experiment.

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O.K., after reading everything my latest stab at what I want. Comments please.

Front

Camber - 0.8
Caster 8.0
Toe 0.0

Rear

Camber - 1.0
Caster + 0.8

Everything is within factor spec limits.
Toe 0.0

 

Sounds like a most excellent compromise between performace and tire wear.

 

Sorry for the delay, I rarely see less negative camber in the front than the back. this will likely take the car towards understeer, most track/autx'ers move more toward oversteer.

YMMV

 

I'm running -1.3 degree cambers both front and rear with one washer removed from the A-arms at both ends. No noticeable uneven tire wear. My driving includes mostly local, winding canyon and county roads. Car is super stable without any hints of oversteer. Also using aFe swaybars front and rear.

 

I already did that by going to heavier Z06/magride rear sway bar.