Thinking about installing an BMW M6 engine in my Z

[wheee!]

I second the Track or Thrust angle setting. Nothing worse than a dog tracking car....

My preferred setup is more like -1.2 front and-1.7 rear camber. This depends on a square or staggered tire setup too. I run staggered on the 370. I will probably run staggered on the 280 too. Corner turn in is usually improved and understeer shouldn't be an issue.

[grannyknot]

5 hours ago, 240260280 said:

Caster: 4 to 6 positive. The actual number between 4 and 6 is not important, only that both sides are the same.

Positive! Yikes, I'm going to have to add an inch to the T/C rod to get that, I guess I better start looking for aftermarket T/C rods.

My worst caster setting is  neg -2.9* and I need to make that pos 4.0*  Can anyone tell me what 7 degrees of movement translates into in inches?

Edited August 15, 2017 by grannyknot

[Captain Obvious]

Well ballparking the length of the strut body from top mounting bolts to wheel centerline... I'm estimating that length at about 18 inches. And with that length of 18 inches, then the longitudinal shift resulting from 7 angular degrees pivot around the top mount would be about 2.2 inches shift.

I gotta believe there's something else going on. I can't believe you need to push your wheel spindle forward 2.2 inches!! That chassis was rusted, but not accordion crunched, right?

Are you sure there wasn't some confusion about positive and negative directions? Maybe their alignment rack was made in Australia? 

On my car, I can stand alongside the car with my body centered along the line created by the two top strut mounts and look down at the wheel. I can tell that my spindle tips are farther forward than the line between the strut tops. In other words, I can SEE some positive castor on my car. Never measured how much, but it's enough that I can tell which direction it is.

[240260280]

Some may chime in about wheel spacers on the front.... or they may not...shhhhhhhhh

[grannyknot]

7 hours ago, Captain Obvious said:

Are you sure there wasn't some confusion about positive and negative directions? Maybe their alignment rack was made in Australia? 

Correction, those caster numbers are in fact positive (never trust the word of the kid running the alignment rack).                 The tops of the strut are behind the ball joint angling forward.  So a fairly thick washer added against the shoulder of the T/C rod on the D/S should get me in the ball park.

[Captain Obvious]

Whew! Well that's better! Glad I asked.

If you want to push both sides to five degrees, you should be looking at about .94 on the left side and .63 on the right.

Or if you just want to make them the same, you want your fairly thick washer to be about .3 more on the left than the right.

Of course, remember that I'm no suspension expert and I reserve the right to have completely screwed up those calculations!! 

[EuroDat]

49 minutes ago, Captain Obvious said:

Of course, remember that I'm no suspension expert and I reserve the right to have completely screwed up those calculations!! 

Captain, Im a bit the same. I don't know what mine is atm, other than caster is slightly positive. Ill just sit on the side line and watch Chris do his thing.

[grannyknot]

Thanks Chas, just enough rope here to hang myself

Captain, I will need after market adjustable T/C rods to get to 4-5* caster but I'm just trying to tweak it enough to get through a track day on the 20th of Aug. using the stock T/C rods,  so .3" of washers on the D/S will at least equal them out. True it is 18" from the shock nut to the wheel center but the T/C rod is attached to the top of the ball joint that 5-6" South of the wheel center line, that might mean I'll need a bit more than .3", what do you think?

[wheee!]

You need these...

[Captain Obvious]

16 hours ago, grannyknot said:

the T/C rod is attached to the top of the ball joint that 5-6" South of the wheel center line, that might mean I'll need a bit more than .3", what do you think?

Yes, I agree. Estimating the total length at 24" (the 6 from ball joint to wheel center plus 18 from wheel center to top of strut), you would need about .42 inches added to the T/C rod length to add one degree to the driver's side and even things up. Thanks for checking my work! 

So if you throw a couple washers in there, are you going to take it back to the rack again before the track day and make sure we know what we're doing?  

On a related note, I just got done with some suspension work on our Family Truckster and I'm currently messing around with alignment stuff on that thing. It's got four adjustable wheels and I'm poking around trying to decide if I want to try to do it myself or take it to a professional.

[Mark Maras]

 Cap'n, should you want to give it a try, www.circletrack.com has a write up on the subject of alignment using strings. Looked quite interesting when I read it a few years ago.

[wheee!]

Our car club books a garage every now and then for a club alignment day. $100 a car for a custom alignment including a DIY experience. Even aligning with the driver in the seat for track balance. One of our members manages a tire shop...