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I am racing at Thunderhill in two weeks, I asked my local alignment shop to align my car to the spec sheet I provided. I showed them the Pfadt alignment recommendation for performance street - track use with street tires.
This calls for Front Camber to be -1.1 to -1.3, Caster between 7.5-8.5 and toe between 0 and -1/16"
The rears should have camber at -0.7 and -0.9 and total toe between -1/8" and -1/16"
What I got back was front camber at -0.2 and -0.8
front caster at 7.0 and 0" of toe.
the rears camber came back good at -0.8 but only 0" toe
They stated if they tried to set the camber, the caster suffered and vice versa..
The way it is now, is it good to race on or should i get another alignment back to stock? OR, is there any parts I need to buy to make such an alignment possible?
The car does feel a bit twitchier at higher speeds.
I am racing at Thunderhill in two weeks, I asked my local alignment shop to align my car to the spec sheet I provided. I showed them the Pfadt alignment recommendation for performance street - track use with street tires.
This calls for Front Camber to be -1.1 to -1.3, Caster between 7.5-8.5 and toe between 0 and -1/16"
The rears should have camber at -0.7 and -0.9 and total toe between -1/8" and -1/16"
What I got back was front camber at -0.2 and -0.8
front caster at 7.0 and 0" of toe.
the rears camber came back good at -0.8 but only 0" toe
They stated if they tried to set the camber, the caster suffered and vice versa..
The way it is now, is it good to race on or should i get another alignment back to stock? OR, is there any parts I need to buy to make such an alignment possible?
The car does feel a bit twitchier at higher speeds.
Sounds to me like they half assed the job. Have they done good work for you previously or is this the first time at this shop?
I'll happily trade a little caster for correct and even camber. I'd have expected a decent shop to do the same. What's the point in having a car that gains camber side to side equally via caster if the static numbers aren't the same (or even close)? Why they put the rears at zero toe vs some toe-in doesn't make any sense either.
I have been to this shop over the years, owner is a fellow drag racer, but maybe not know so much about road racing or aligning outside of factory spec.
Honestly, I am very unfamiliar with alignments too. I just wanted a spec that would help give me an advantage at the track.
They did offer me to come back and get it checked out again before the race. I should suggest getting the Camber as close to -1.2 as possible at whatever sacrifice they have to make for caster?
Also, I should ask to get the rears toe in between that 1/8 and 1/16 spec?
I had a very similar experience yesterday. Walked into a local specialty alignment shop (as opposed to the West End who knows Corvettes) and had them align it to Pfadt street tire specs so I can AutoX this weekend.
Owner / 'expert' argued with me on front and rear toe (he said zero so the car wont push) and wasn't sure he'd be able to get me the front camber number (+/- 1.6). Claims he does Vettes for the track all the time and this is how they all do it. He actually took out caster to achieve camber (from +8.5 to +7.5), which is common with the eccentric cams. In the end I got 1/16th toe front and rear and I'll live with it until I upgrade a few things.
Bottom line for me - when you want it done right, go to folks that know your car and can do it to your specs.
I am racing at Thunderhill in two weeks, I asked my local alignment shop to align my car to the spec sheet I provided. I showed them the Pfadt alignment recommendation for performance street - track use with street tires.
This calls for Front Camber to be -1.1 to -1.3, Caster between 7.5-8.5 and toe between 0 and -1/16"
The rears should have camber at -0.7 and -0.9 and total toe between -1/8" and -1/16"
What I got back was front camber at -0.2 and -0.8
front caster at 7.0 and 0" of toe.
the rears camber came back good at -0.8 but only 0" toe
They stated if they tried to set the camber, the caster suffered and vice versa..
The way it is now, is it good to race on or should i get another alignment back to stock? OR, is there any parts I need to buy to make such an alignment possible?
The car does feel a bit twitchier at higher speeds.
That's a big damn mess, you have almost zero camber on one side and below -1.0 on the other. I could be wrong but I don't think that's enough neg. camber to even be within the (ridiculous wide) range of stock settings.
You got garbage, sorry to say. Find a race shop with a lot of history on doing track setups. Or another regular shop that knows how to do alignments. It's not rocket science.
My $.02 (probably have done 1,000 alignments by now...): caster isn't nearly as important as camber at the track. Depending on the tires used and the tightness of the suspension bushings, -1.2 may not be enough, but is a good starting point. 0 F toe also good to start... probably not going to notice much difference btwn a little toe out and a little toe in. Toe out helps the car on turn in, but can shorten street tire life. Toe in at the rear for stability! Pfadt's specs call for toe in, but show "-" (minus) in front of the rear toe number, which typically means toe OUT to an alignment shop. Rear toe out will make the car "lively" on the track. Maybe good for auto X, but probably not what you want at T-hill.
I am racing at Thunderhill in two weeks, I asked my local alignment shop to align my car to the spec sheet I provided. I showed them the Pfadt alignment recommendation for performance street - track use with street tires.
This calls for Front Camber to be -1.1 to -1.3, Caster between 7.5-8.5 and toe between 0 and -1/16"
The rears should have camber at -0.7 and -0.9 and total toe between -1/8" and -1/16"
What I got back was front camber at -0.2 and -0.8
front caster at 7.0 and 0" of toe.
the rears camber came back good at -0.8 but only 0" toe
They stated if they tried to set the camber, the caster suffered and vice versa..
The way it is now, is it good to race on or should i get another alignment back to stock? OR, is there any parts I need to buy to make such an alignment possible?
The car does feel a bit twitchier at higher speeds.
If you're driving THill with 0 rear toe, remember to keep your mirrors clean because your going to need them. I'll bet it feels twitchy.
Get an alignment shop that knows track cars. Don't worry that much about castor, anything above 6 is fine as long as you get the camber you need. Also, Pfadt's specs are a little light duty even for street tires. You can push that thing out -1.5 camber and your streets will still last reasonably well.
My $.02 (probably have done 1,000 alignments by now...): caster isn't nearly as important as camber at the track. Depending on the tires used and the tightness of the suspension bushings, -1.2 may not be enough, but is a good starting point. 0 F toe also good to start... probably not going to notice much difference btwn a little toe out and a little toe in. Toe out helps the car on turn in, but can shorten street tire life. Toe in at the rear for stability! Pfadt's specs call for toe in, but show "-" (minus) in front of the rear toe number, which typically means toe OUT to an alignment shop. Rear toe out will make the car "lively" on the track. Maybe good for auto X, but probably not what you want at T-hill.
I used Pfadt's specs. Just so I'm clear, toe out in the front and toe in for the rear? If so, I'm gonna have to fix that again.
I used Pfadt's specs. Just so I'm clear, toe out in the front and toe in for the rear? If so, I'm gonna have to fix that again.
For toe OUT in the front, IMO, don't put too much, just a touch. For toe IN in back you can go much more. Not giving specifics as it depends on a dozen other parameters in your setup.
You are not going to get the caster settings you are asking for on a C5. You can on a C6 but the C5 doesn't seem to have that amount of adjustment built into it.
I used to run -1.3 front camber on my C5Z and if I remember correctly the caster came out somewhere around +6 to +6.5 degrees. Give up on the caster to get the camber. However, if you are getting very low caster readings you need to take a look at the control arm bushings. The bushings on my 97 slipped allowing the LCA to rub against the cradle and reducing the ability to get any positive caster. My caster readouts were around +2. Since the parts were not readily available before my track day the dealer mechanic took the LCAs out, installed large washers to protect the cradle and then used studs for the UCAs so he could insert standard alignment shims behind the UCAs to get the caster I wanted. It worked great until I could get replacement bushings.
Make sure you have the correct toe readings. This is a matter of interpretation and most shops and machines accept positive readings as toe in. Pfadt as does the GM chart above used negative to indicate toe in. You need toe in (positive) in the rear to keep the backend planted. Toe out (negative) on the front can get you quicker turn in but can lead to wandering when driving on streets and highways. I always preferred just a shade of front toe in to calm down the wandering. That way the car was drivable on both the street and track although I did give up some turn in response.
Whenever I had a shop do an alignment I always wrote on the sheet whether I wanted Toe In or Toe Out. That way the mechanic could interpret things the way he was used to and usually avoided mistakes caused by confusion over the sign.
I have been reading and researching like crazy to prepare for my own adjustments this coming monday.
I am a little confused, do I want toe in or out on my front tires for racing on a track?
Pfadt sheet says toe in all around. Others are saying fronts should be slightly toe out.
I understand the rears will be toe in. on the rears, since camber is good from my recent alignment, i am just going to turn those rear tie rods 4 flats to get my toe in to the desired 1/16" in.
The fronts, once I measure camber, (I am shooting for -1.3° on the front), I want to adjust the front tie rods 2 flats to edge me in from my current 0.00inches to a bit less then the recommended 1/16"
When I read about people saying that adjusting the tie rod by 3 flats is aproximately 1/16", does that mean the total toe or individual tire? I assume and wrote my above post based on the idea that its total toe.
Toe is too critical of a setting to just adjust and hope, especially when it is very easy to set up some strings and measure. Incorect toe setting will destrot your tires fast
Are u near San Jose? When I was in the bay area I would use Custom Wheel and Alignment. They know what they are doing. Probably lots of knowledgeable shops around if your willing to pay.
When talking about toe I use the terms toe in and toe out to eliminate any + - confusion.
Like all the others have said, your current alignment is junk, and it needs to be fixed.
I encourage you it learn to do it your self. Every time you make a change you may to reset everything. The first couple of times your eccentric washers slip you will need to reset everything.
Just make sure you level out the floor.
With street tires I run
Front 1/16" toe OUT
Camber 1.2
Caster 6-6.5
Toe is too critical of a setting to just adjust and hope, especially when it is very easy to set up some strings and measure. Incorect toe setting will destrot your tires fast
Are u near San Jose? When I was in the bay area I would use Custom Wheel and Alignment. They know what they are doing. Probably lots of knowledgeable shops around if your willing to pay.
When talking about toe I use the terms toe in and toe out to eliminate any + - confusion.
Like all the others have said, your current alignment is junk, and it needs to be fixed.
I encourage you it learn to do it your self. Every time you make a change you may to reset everything. The first couple of times your eccentric washers slip you will need to reset everything.
Just make sure you level out the floor.
With street tires I run
Front 1/16" toe OUT
Camber 1.2
Caster 6-6.5
Rear
1/8 Toe IN
Camber .8
I agree with ando about counting the flats & hoping toe changes where you want it.
So i went ahead and did it anyways. This is what I did.
Used a piece of 2x4 running down from the edge of the front and rear of the wheel to the floor and marked the edge with a sharpie. Repeated on the other side. Moved the car. Measured the distance between the two points on both sides of the car. I forget the exact measurement now but the front of the rear wheels came out to something like 76 1/4". the rear measurement of the rear of the rear wheels came out to 76 1/2". Meaning a little over 1/4" distance apart, divided by 2 means 1/8" toe total. The actual reading was slightly under 1/4" difference, so I am probably closer to 3/16" total toe. Car feels much better driving it now.
The rear tires camber was good too from the alignment so I am gonna leave them for now and next attempt to adjust the front camber to aprox 1.3degrees and see how that goes.
Next I am going to attempt to fix the front camber.
I don't think the 2x4 method is going to give you the resolution you are looking for.
Toe should always be checked after making an adjustment, as all the other changes, (camber caster) will change the toe.
Incorrect toe WILL destroy tires quickly.
The string method works and is easy to implement.
This was the rear tires only. I have no further adjustment to do on the rears.
The problem was you were measuring total toe. That is fine in the front if you don't care much about the angle of the steering wheel. However, in the rear you have to worry about thrust angle since the rear wheels are not free to turn to the center. If the thrust angle is to far out the car will dog walk and handle unusually.
If you want to check your thrust angle get a couple of toe plates to set against the rear wheels and fasten a Sears 24 inch laser level to the top of them with the level running across the outside of the tires. Then place a jackstand with a ruler taped to it so the ruler contacts the center of the front hub. Turn on the laser and measure the distance the light beam is from the center of the hub and then take the same measurement on the other side of the car. Try to get the two sides within an 1/8 of each other. If you have a helper you can forgo the toe plates and jackstand. Have the helper place the level against the tire and then adjust it to the measuring stick you are holding to the center of the hub.
02-20-2015, 03:10 PM
C5Z track alignment question
Have they done good work for you previously or is this the first time at this shop?
