AlterKtion - True Pro-Touring Suspension

I usually stay out of debates, but I thought it a good idea in this case, to clear up some misconceptions. Top Heavy is right, with bad kits the only design work is the advertisment, and good kits are designed assuming a primary use, compromising other uses for the gains.
I wont talk about others, but I can divulge a few tidbits on the Alterktion...
On the compromises for the design, leaf-sprung drag cars are the ones that have to work on it. We moved the travel range up 1.25", so you lose that much rise when you leave. That drops your 60' time, which requires some adjusting to get it back. 4link and ladder bar cars dont really need the travel and have lots of adjustment available, so there's no concern, but the leaf spring cars have a hard time getting the time back. The other compromise is that 15" rims are limited to 6 inch wide. 17" and up is really what is was intended for, although there are some really nice stock looking customer cars with rally's or painted steel 6" on the front.

Concerning the physical layout, the bad news is that modifiying the system with other spindles and a-arms is impossible without totally butchering everything - all the parts are designed together assuming certain dimensions. Aside from physically mating the parts, deviating from any one dimension would require changing all the other dimensions in order to have even the slightest semblance of decent geometry and/or fitment. Suspension design is typically easy until you try to fit it around an engine.

However, the good news is that I've always worked toward a design that accomodates the use youre looking for. Call it pro-touring or whatever, I always called it a street car that will take corners faster than you have the guts to. If I get scared before the car does, I call it good :)

Anyway, with a 26" tall front tire and wheel travel centered, you have 5.5" under the crossbar of the kframe, and 7.5" at the rocker panels. The system also has 5.5" of total wheel travel with a track width 0.125" wider than stock discs.
In reality, most of us run with 4.5" under the K frame and 25.5-26" tires, which works best. On a street car, its better to have a bit more rebound travel to suck up the bigger potholes, and you dont want more compression than the car can safely handle - you can channel the suspension up into the car, but the full travel range cant be used because the car hits the pavement before it bottoms. So it's best to design the system where the shock will bottom with the crossbar 2" off the pavement. Even at this point, the exhaust would be scraping. Most of us are running 3" exhaust, and that hangs down a couple inches. Milodon's road race oil pans are above the crossbar, so nothing to worry about there.

In my own car(69 dart/528hemi/6spd), which is currently undergoing it's 3rd redo, I have 5" under the crossbar and 7" under the rocker panels with 25.25" front tire(255/35/18). I also raised the engine and trans 1" higher than stock, which got the big exhaust up close to the floor, but there's still only 3.5" under these big hemi headers. A stiffer compression setting on the shocks will keep it off the ground, and I normally like a stiffer setting anyway, because I beat the beans out of everything...I've had my SRT Charger airborne more than once over railroad tracks and the 4" high front airdam has never touched the ground.

But, if the normal single adjustable QA1 shocks arent enough, we can do doubles, or for the really serious folks, we use custom-made afco shocks, low friction balljoints and very high durometer a-arm bushings.

As for geometry... Bumpsteer is 0.015"/inch of wheel travel. 1.5 degree camber gain with stock upper mounts, ackerman within 2 degrees of ideal at the maximum 18' turning radius. When roll angle and any amount of steering input are combined, roll center migration remains under 1.25". There is 1188lbs of roll resistance per degree of roll but we did it with a smaller bar, so ride quality remains pleasant when you're out on the interstate. Anti-dive is at 49.9% so there's no nose-diving on the brakes, and (assuming my rear suspension for the test), level ground roll rate on a 3200lb car is 1.77 degrees/G - this is with a rear 4-bar suspension with no rear sway bar. Roll center is -1.5" to 2.5", and I'd like that to be a bit higher, which gets me to the next little tidbit of info. At least with our system, lowering the front upper control arm mount 1" increases camber gain to 1 degree per inch of travel, raises the roll center so its in the 1" to 4.75" range, cuts down on caster change. However, it also lowers anti-dive to just 8% and bumpsteer goes up to 0.031"/inch of travel.

I make weld-on upper control arm mounts that can be used to fix or alter stuff, or use the system in a street rod, but I'm not making that change in my own car. The gains and losses are extremely minimal and I'd need stiffer springs to make up for the lost anti-dive, which means a harsher ride quality, so I just decided its not worth doing more work just to say I changed it.
I think I covered all thats been mentioned here, but if not, feel free to ask...