Cobrakev

Thanks Al, I will check that out first thing in the morning.

Kevin

F1Fan

Hi Peteway,

You have some of the best springs and dampers out there for our cars at the moment for street and occasional track days, great choices here. Yes, the Tokico strutswith Eibach springs installedare stock replacement parts and need no additional parts to be installed but there is the issue of camber. Some cars I have installed springs inI could getaway with simply tweaking the strutbearing mounting bolts at the top of the strut towers and achieve a usablecamber setting, somerequired camber bolts orSteeda camber plates and were still marginal. With the Eibach Pro Kit sportsprings you will probably, as in more than likely,need to install some sort of camber adjusting device to get your front camber to adjust to a reasonable setting for the street.

For a street car the maximum camber setting if you have any hope of getting goodmileage out of your tires is 0.5-0.75 degrees negative camber. The amountyou can get away with depends onhow hard you corner how much of the time, tire pressure etc. If you are a handling fiend and don't mind giving up 5,000-10,000 miles of tire life go the maximum 0.75 negative camber but be warned you will begiving upconsiderable mileage in the name of handling and grip and on high performance tires this mileage losses as a percentage is worse than the stock all season tires. If you want to get the mostmileage out of yourtires use no more than 0.5 negative camber. Of course the trade off is in cornering grip and handling balance on the track but on the street this is less an issue.Eibach's camber bolt kits are the sameparts as supplied by SPCbut just cost more, both will work fine.

If you are serious about having good tire life and good track grip buy a set of Steeda's street adjustablestrut bearings. These buggers are the bomb with muchof the precision feel and location of the Steedarace strut bearing assembly with none ofthe NHV. To top it off you also get 2 degrees of camber adjustment at the top of thestrut!This gives you the option of setting up yourcamber withcamber bolts on the strut ears at a streetable 0.5degrees negative camber andbeing able toeasily setyour camber at the track gaining up to 2.0 degreesadditional negative camber!Depending on your tires 2.0-2.5 degrees negative camber shouldbe enough to make your chassis work wellif you set it up with this in mind when you do the base alignment. You will need to checkyour toe setting at your street setting and at the trackcamber setting to see whatthe toe does atwhatever your ride height is. You should do this at the alignment shop and write it down for reference. Some ofyour toe changes may be able to be finessed using a bumpsteeer kit but you will need to work it out depending on your ride height and any other modifications done to the chassis.

At the rear an adjustable Panhard bar is VERYimportant for a car used on a road course and don't forget the Panhard support bar to help locate and balance the loads being put into the chassis. A good adjustable Panhard bar is NOT justused to re-center the axle in the chassis. The Panhard bar is yourone link controlling the axle when cornering! All of the feedback during cornering comes from this single link to the axle. The best feel anddriver confidence comes from a very stiffPanhard bar with stiff bushings or rod endsand on the chassis side a Panhard barpickup point that is very well located. This is why I highly recommend using Steeda's Panhard bar and Heavy Duty Panhard bar support brace to provide the best possible location of the chassis side Panhard bar pickup point. As I'veposted many times before,the materials used for suspension componentsmake a big difference in driver feel, confidence and performance. The Steeda Heavy Duty Panhard bar braceis really a part that helps long term to keep your chassis stiff by spreading the loads into the chassis to more than a single point. For a drag oriented car this is afine point to make but for a roadcourse car is the difference between a happy, confident driver anda driver who is not as confident.

Pinion angle is the angle difference in degrees between the axis of the driveshaft and the axis of the pinion shaft. The driveshaft and pinion shaftneed to be misaligned very slightlyin order to protect the joints and bearings in the drive line during heavy load, like hard acceleration. I say protect the joints and bearings but you also help reducedrivetrain losseshence more efficient (faster). The reason is that given the forces involved the axle tries to rotate the top of the differential towards the rear of the carand the bottom towards the front of the car. There is a small amount of give in the bushings at the ends of our control arms and we compensate for this "freedom" by setting the nose of the differential slightly downward so once we load up the drivetrain we get a nice alignment when it is most critical.With the stiff polybushings and stiff control arms used on the S197GT's 3-link suspensionthere is minimal change in pinion angle when loaded up so we need lessstatic nose down angle. How much depends on your chassis components used andhow much power you make. Simple see? [sm=exactly.gif]

So knowing this to answer your question we want to keep the axle under control when we load it up and the best way to do this and still drive it on the street is to use stiffer control arms and bushings.All you really need to set the pinion angle is to have one or the other set of control arms be adjustable. The easiestcontrol arms to get accessto on a regular basisare the lower control arms. The UCA isaPITA to adjust unless you have a drive on lift. So unless you are under the car a lot just use a nice stiff fixed length UCA like my p

Steven6095

Is there a factory range specified for the pinion angle? How do you measure pinion angle?
I have been sitting here reading this contiplating my own upgrades and just keep having the thought - if you need adjustable ones, what do you adjust too?????????????? Gear / rear end whine possible from bad pinion angle?

CrazyAl

There are a LOT of threads about how to measure and adjust pinion angle. Use the search.

The exact adjustment depends on your configuration. If you have a mostly stock rearsuspension the most common setting is -3 degrees. This number can be changed to -2 or maybe even -1.5 if you have more aftermarket parts in the rear. As your rear end parts get stiffer there is less give under acceleration, so the angle doesn't have to be so strongly negative.

If you have a 1-pc driveshaft, set the angle so that the pinion flange is paralell to the transmission output flange.

peteway

WOW!
Thanks for all the good info. I have a set of BMR camber bolts that will be used as well. This car is a daily driver for me that I drive hard so I won't be setting it up for the drag strip. I'll probaly go with the adjustable lower control arms and non adjustable uppers.
I don't feel comfortable making the pinion angle adjustments myself so after I get all the parts in I will install what I can and have a shop do the rest and make all necessary adjustments.

Thanks again, ALL this info is great and more than I expected.

Cobrakev

Al,
Do you by chance have a pic of these camber bolts, or where would I look for them? Tried looking for them today, and didn't see anything different.

Thanks

Stewart

http://stangsuspension.com/store/com...idproduct=1052

ilmor

Questions - what issues will result if an adjustable panhard bar is not used to re-center the axle? How does the rear axle become un-centered ifthe body islowered?

northy_polk

i followed just about everything up until this point. I have the Steeda HD Upper Strut mounts that allow for some camber adjustment [up to 1 degree], but I'm not sure what to do from here. I bought them because i was trying to get rid of a thunking noise, not for track performance. But now I'd like to take advantage of their slight adjustability. So. . . the alignment shop puts the camber bolts in there and gets the alignment set for street, but when i get to the autoX/road race, i can adjust them by giving them thedesired amount of "turns"to provide more camber [toe out?] that is more appropriate for the track. I realize it's not exactly this easy, but I hope I communicated what my question was!

dkegel

No issues other than the driver's side wheel will stick out a bit farther than the passenger wheel. There are variances in every car though, so just measure yours and see how bad it is. Drop a string with a weight on it (plumb bob) from the top of the rear wheel well and measure the distance to the center of the wheel. Then do the same on the other side. See if there's much of a difference.

The reason the axle shifts is because the panhard bar (which located the axle to the chassis) swings on an arc. As you lower the chassis the outer end of the bar moves towards the driver's side slightly as it moves along it's arc.

I hope this helps

Dave Kegel