Ideal Geometry

[Silver69Camaro]

I'll bite. I actually have no problem sharing our data, because somebody can't really just take the numbers and copy it. If you could, you wouldn't need us because you clearly have the knowledge and know-how to be doing it yourself. Trying to copy the whole package is very difficult. Anyway, I've shared this information before on and off topic.

Anyway, per your listings:
Roll Center location Static: +1.9"
Roll Center Migration In Roll: 0.258" / Degree of Roll
Roll Center Height in Dive and Lift: 1 to 1 ratio
Caster: +6 Deg.
Camber: -0.5 Deg (Street alignment, but adjustable to stupid amounts)
Camber gain per inch of travel: 0.6+ Deg Neg. / Inch of Travel
Caster gain per inch of travel: 0.5+ Deg Pos. / Inch of Travel
Toe: Up to end user
Ackerman for a given steering input: 1 Deg. Per 20 Deg. Of Steering
Bump steer: .014 / Inch Of Travel
King Pin angle: 9.2 Deg.
Anti-dive: 6.5 Deg.
Ideal amount of body roll to design for at max lateral-g: Rougly 2 to 3. I wont give the exact answer here.

We also have exact models of C6 suspension parts that allow us to accurately locate pivot points and ball joints. No dial calipers and measuring tapes here.

Like everyone has said before, this is a system that we believe works best for these vehicles. We have lots of time under our belt to give us priceless experience and know-how.

[ccracin]

Matt,

Thanks very much for jumping in. You are one of the "Heavy Hitters" I was hoping would jump in. Just to be clear again, I am not trying to garner anyone's secrets to copy their product. That's I why I say "ideal", knowing that compromises have to be made sometimes for packaging. If you didn't have to package it in an F, A, G ..........body, would you be looking for something else to make it better? I give you great respect for publishing "actual" numbers for your products. In fact I already had great respect for your products, enough that I used your stuff on our project and did not try to re-invent the wheel. Anyway, back on task. If the numbers you posted are for your street set-up, what tweeks would you recommend for high speed track days and lower speed auto-x stuff? Thanks again Matt, you and the rest of the Morrison team are top notch.

later,

[Silver69Camaro]

Thanks for the kind words.

The only things I would change are simple alignment basics; camber and toe. I generally try not to increase caster (doesn't really need much more anyway), because it raises the outer tie rod pivot location and can increase bumpsteer. Not much, but it's there.

For camber, obviously that depends on your tires. The camber gain is fairly aggressive in this suspension, so 0.75 to 1.5 degrees is all you need (static) unless if the tires spec more. Toe is fun to play with, and I like to have slight toe out, as little as possible. Works very well.

We also carry a line of stuff to "fine tune" our suspension. Solid rack mount bushings, adjustable flow steering pumps, custom rack torsion bars, etc.

[XcYZ]

Awesome info, Matt. Thanks for posting.

Originally Posted by Silver69Camaro

We also carry a line of stuff to "fine tune" our suspension. Solid rack mount bushings, adjustable flow steering pumps, custom rack torsion bars, etc.

Solid rack mount bushings... is there much of a demand for those? I'd guess you have seat time in cars with them, what do you think of that setup?

[ccracin]

I agree with Scott. What are your driving impressions? Since I have your front end components I am wandering if these parts would be beneficial to our project. Although I should probably get the thing on the road before this is important. I bet they don't do a bit of good for a truck on jack stands!

Let's hear from some other people too. What does everyone else have to say?

[pro-tour79]

From what I get from the question " ideal geometry" is specific settings, the sheet metal around the chassis does not matter, but what does matter is weight, weight bias, CG, wheel base and track width, roll axis, and all of this in turn affects the settings, and driver feel, and spring, and sway bar rates.
but some items can be answered with "as little as possible" such as roll center migration, bump steer.
It is important to keep all that in mind.

[ccracin]

Originally Posted by pro-tour79

From what I get from the question " ideal geometry" is specific settings, the sheet metal around the chassis does not matter, but what does matter is weight, weight bias, CG, wheel base and track width, roll axis, and all of this in turn affects the settings, and driver feel, and spring, and sway bar rates.
but some items can be answered with "as little as possible" such as roll center migration, bump steer.
It is important to keep all that in mind.

You bring up some very good points. This kind of information is what I was hoping for from this thread. I talk to people all the time at local shows and cruises. They talk about improving the handling of their cars but have no idea what it takes to do that. They don't even know what questions to ask. They only know what they see in ads and from marketing wizards. The "average Joe" has never heard the terms Matt, You, and myself are throwing around here. If someone is going to spend thousands of dollars to upgrade their car or truck (we can't forget the trucks ) they should actually get an upgrade rather than some pretty tubular control arms that don't do anything but be tubular. Don't anybody get upset that sells tubular control arms! They have a place, but I just thought an open discussion about these principals would help alot of people.

As I said after your first reply, the sheet metal doesn't matter other than for weight and balance. I would argue however that if you look at the hierarchy of what systems to resolve first, the mechanical geometry of the front end should be considered first. This is only my opinion, hence why I brought it up first.

You have to take one system at a time and evaluate it. When you have what you believe is a good solution then you evaluate it against the other systems. If changes have to be made, then repeat the process. This is why some of these parts cost what they do. Quality vendors take the time and spend the money to evaluate these systems so they can educate you as you move along. Others spend the money on marketing alone. Hopefully this discussion will help figure out which is which for yourself.

Track width in an "ideal world" would be much wider than is practical in street cars. That is why I said earlier 'ideal" within reason. Wheelbase comes into play in my mind when you start evaluating both ends of the vehicle with regard to weight bias, balance, and evaluating the roll axis along with the rear suspension system.

It has been my experience that evaluating each end of the vehicle independently and then working to balance the 2 gets you closer faster than jumping back and forth. Any thoughts?

Anyway, thanks for the continued input pro-tour79. This is getting good. I threw out enough of my opinions, so lets see if anyone jumps in to tell me what is wrong with the way I do things. If anyone agrees let us know and hopefully we'll get some more good info.

Later,

[Silver69Camaro]

Originally Posted by pro-tour79

From what I get from the question " ideal geometry" is specific settings, the sheet metal around the chassis does not matter....

I totally agree with you, but you have to take "marketability" in mind. I absolutely love our Musclecar chassis, where sheetmetal truely does not matter...it all gets cut out and suspension function takes top priority.

BUT...if we had a "bolt-on" front clip for first gens that required cutting, we couldn't sell it. There is a fine balance between packaging and suspension optimization that is probably the hardest part about my job. For instance, my first instinct was to make the Camaro front clip hub track width about 62" wide, quite a bit wider than stock, but I had to bring it down to 60.5" in order for most guys to find a wheel that would fit. This increased bumpsteer from .001" to .014", which thankfully isn't a big deal.

[Silver69Camaro]

Originally Posted by XcYZ

Solid rack mount bushings... is there much of a demand for those? I'd guess you have seat time in cars with them, what do you think of that setup?

I like them alot. Granted the AGR urethane bushings are pretty hard, these lock the rack housing to the crossmember via male and female chamfers on the mating surfaces. You do get more road feel, but to my surprise, I don't feel more vibrations through the steering wheel. When a front tire loads and unloads, you can feel it in the wheel and allows you to understand what the car is doing. For the price, I consider it a good upgrade. Combine that with the KRC power steering pump, you've got a steering feel that is absolutely wonderful.

There are downsides. If you hit a pothole large enough to ruin a wheel, there is a greater chance the rack will be hurt as well. Considering the scrub on these cars is pretty low, I don't worry about it.

[ccracin]

Thanks Matt. When we get our project on the rode, we'll see how it feels. Because in the true sense our project might not really see anything more than spirited street action, the urethane mounts may be the ticket. Thanks again for the info.