3 link suspension

[iapitapun]

Originally Posted by Damn True

Then, I go on-and-on about how it seems you have no freakin idea what you are doing since you have yet to publish the data on the project you are STILL WORKING ON.

You know what. Forget it. I thought this was a completed design available for consumption. I guess I was wrong.

I am not asking for drawings. All I wanted was few few resultant values from their design. I am not going to back calculate anything.

So because I ask questions, I am some evil person trying to steal ideas. No.

I realize mark is not here and I am sure he will respond accordingly. Here is a scenario.

Six months down the road Mark and company are selling this. I stumble onto their web page and it talks about the AS geometry and how it is adjustable. I think cool, what kind of adjustability range is there?

What will the answer be. That is proprietary information, or it is between XX% and YY%.

What would you want the answer to be.

Listen, I am sorry. Hey just because I know some terms and math doesn't mean I want to build my own one off. Relax everyone. No one is trying to steal anything.

[Damn True]

I'm just suggesting you dial back the tone just a bit.



....and btw, I would never actually say something bad about a man's dog. That's just not cool.

[race-rodz]

i'm not gettin into this one..... but i will add, a bare 1st gen 12 bolt housing weighs in at 64# (i just sold/shipped one last week)

i think the q&a's were answered for the most part, and goin off of numbers for suspension programs is fine..... but what will "sell" is when the set up is installed and tested under real world conditions, hard numbers of before/after. so would be customers can have an idea about how the system will improve the performance of their car.

EDITED: some of my reply was answered while i was typing

[XcYZ]

Iapitapun, you're not out of line for asking questions, but what seems to have set off some people is your approach. It's not the questions, it's how they were presented.

[RussMS]

It's not like he's a CPA with a pocket protector and an etch-a-sketch

And what would be wrong if he did? I happen to resemble that remark

No comment on the tech question, that part just gave me a good laugh.

[Steve1968LS2]

Originally Posted by Damn True

Ya know, sometimes on message boards it seems like somone is being hostile and/or accusatory when in reality they are simply being direct. That said, I dunno if it's your intent to come across as hostile, but man it sure seems that way.

Wow.. Mark told me about this thread.. this is even more vitriolic than the Air Ride thread on PT.com except the roles are switched around.. lol..

Lots of good info though.. Oh, and Katz works for Mark.. that is good enough for me to be a believer in what they turn out. I am sure that once the system is on the streets it will be "put though the paces" to give performance data.. after all engineering specs are fun but it all comes down to what the car can do.

[sinned]

Wow, I go to work and look what happens.

I just want to add that you had asked a few very specific questions-

1. Was this designed for a range of ride heights? If so, what is the range and the Jounce and Rebound levels for each ride height.
2. It looks like the tubes for the watts link hang below the diff. How far below, and what is the ground clearance at curb and full jounce?
3. What is the rear roll steer % at each curb height?
4. What is the range of anti squat and anti lift %?
5. What CG height are you assuming?
6. I know you need to remove a portion of the tunnel, do you need to remove any of the floor or trunk to accommodate the rear mount for the three link. It seems like it would limit jounce travel.
7. How long are the links for the watts link? What about the length of the bell crank?
8. What are the tube diameters and wall thicknesses for this setup?
9. What is the weight of the whole system and how much of that is unstrung?

and they were answered if you had read the entire text.
1. Yes, it is adjustable.
2. Just below the axle centerline and ground clearance would depend on your ride height.
3. Neutral at the lower end of the scale.
4. 70% AS and what the heck is anti lift?
5. CoG is about 20".
6. Not sure, I guess he missed that one.
7. How is this relevant to determining if the system will work or not?
8. .100" tube thickness
9. Eliminated 30 lbs of unsprung

[zbugger]

I know this won't help any, but if this is the same thing that is on Lateral 1, I know it works. I've seen the car run the track and it looked better than quite a few factory cars running out there.

Mark, if you ever figure out the tail pipes thing, I just may get this. In fact, if I can figure out how to put the money together, I WILL get this. Just make sure it fits my 2nd gen Camaro. Heh... I've waited two years to drive it again, what's another two?

[Vince@Meanstreets]

70% AS and what the heck is anti lift?

are you serious?!?! You should know this one!! Anti-lift can cause reduction of rebound travel in the rear suspension under braking. Like anti-dive in the front suspension. This is a common trait in 3 link suspensions possibly due to length of upper link. Im no suspension gure so cap that flame thrower iapitapun! heeheeee
He might type off as an axe hole but he's asking the right questions and Mark has no problem with it so why should we? This is the part of being a new business and going to an open market.I think Mark asked us to keep it civil so lets all take in a deep breath and inhale....hold it....hold it.....

[Mean 69]

I'll do my best to make everyone happy, but it is the middle of the night, and I am tired.

A bending moment is present anytime a link is subject to a force that is not purely compressive/tensile (let's forget about torsion for the moment). As the Watt's link is a dynamic setup, the geometry, and therefore force direction will change as the system is placed in bump/rebound. The force will in many cases be applied to the link in a manner that is not directly in line with the centerline of the tube = tries to bend the tube. In the case of the Watt's linkages, this is not a big deal at all because the links are so short. For long trailing arms, it is more of an issue, and the exact same principle applies. It has nothing to do with the fact that it is linked by rod ends. As far as the geometry (i.e. link lengths, bellcrank dimensions), I stated previously that there really isn't any magic to the system, if you model the thing up in Solidworks and move it through travel, you will see what I mean. You have my permission to bring a tape measure and get the dimensions, but this is the sort of design specific info that I will not disclose, I am sorry if you can't understand why.

Again, not trying to sound evasive, but here is the answer to the roll steer, A/S, etc, versus ride height question. There are two adjustment holes for the lower control arms. There are three for the upper arm. There are four position to locate the Watt's linkage. Based upon the questions, it is clear that you understand that roll steer, A/S, SVSA are all completely interlinked, so for every iteration of ride height, there are 24 possible combinations. The ride height "range" was derived by looking at several typical cars. It basically encompasses a "low" height that is basically the same as Charlie Lilliard (Stielow built) "Mule," which we found is about an inch or so lower than my car. On the other end, Stuart Adam's beautiful car sits a bit higher. I do not have the specific numbers in front of me, but the basic range is of the order of 2 or so inches in variation, but you can go lower or higher, we just don't see a real need or reason. If you can give me a reference point of where you'd like to base the numbers, we can model the results and give "numbers." If I sound like a jerk here, I am not trying to be, but given the fact that there is infinite adjustment between the amount of ride height, well, the spreadsheet of values would get pretty long.

The lowest point on the suspension system is where the coil-overs mount to the axle. This point lies above the rim height of a 17" wheel, so if you curb the car, the wheel takes the hit (first). The lower Watt's mount on the axle is only a few inches below the axle centerline.

The design is complete, and it IS ready for public consumption. I am sorry if the answers I have given are not satisfactory, I probably left something out. I would ask that you at least give us the benefit of the doubt, or rather, ask the same questions of everyone who sells this stuff and is even willing to publicly disclose this type of information, and see what you get.

Thanks,
Mark