mark kibort

Yes, you do!!!!

brutus

I hope he means 6 inches of TRAVEL

Carl Fausett

Kibort - our system has the capacity for more travel than the stock system had.

Measured from center of mounting bolt to shoulder on shock shaft:

The Stock Front shocks were 19" extended, 15" collapsed.
The shocks we have selected actually have a longer range of 20" extended and 13.5" compressed.

The Stock rear shocks were 18" extended, 12" collapsed.
The shocks we have selected are 18" extended and 12.5" compressed.

We have more than enough range of travel. Be sure not to confuse suspension travel with shock travel. Kibort referred to it as "motion ratio". There is another name for that, that escapes me at the moment, but his idea is right.

I cant wait to drive them, the tires came today!

Carl Fausett

Going to the shop now... if I don't answer its because I am not at the keyboard. I will check back and try to answer all your questions again later.

Thank you for your interest.

GregBBRD

No armchair quarterbacks....just pure logic. Remove yourself from the business part of that mount and just stop and look at it., logically. You don't need to be a suspension engineer to see the problem.

That mount is going to sound like a train going down the tracks, while it tries to "cut" holes into the inner portion of the rear control arm, regardless of if it is perfectly centered under the load, or not. Even if it was perfectly centered at droop, that "center" is going to change as the arm sweeps through its arc, slamming it first one direction and then the other, at the load swaps from pulling to pushing.

Really hard to believe that you are still not testing "new products" before they are released to the public.

I'd have guessed that you would have learned this lesson, with the sway bar kits, the front control arms, ad nauseam.

You are certainly welcome to sell whatever you want.

Have fun!

I was just trying to help, not "ruin your thread", BTW!

Back to regularily scheduled programming.

86'928S MeteorGrey

Carl Fausett

I know. Like a guy I saw develop an "oil control fix" with the customers money, which was nothing more than a $3000 glorified scavenging system, that only treated the symptoms of the oiling problem and did nothing to address the cause. Then he was bold enough to post "I have solved the 32v oiling problem" on the Renn. Wild. You mean like that? THAT kind of development and sales of what was really just a prototype? Or was that one-of solution developed on the customers car? Is THAT what you mean?

I can say this, I develop these items with my own money, I ask for no "buy ins" or "group buys" and I install them on my own car. I announce them as new because they are NEW. You can read about them. You can buy early, wait until the season has proved them out, or not at all. I tell the truth and the consumer makes their own decision.

I have no doubt that as the season progresses, they will become refined even more. I would not presume that we got it dead-nuts right the first time. Not even Porsche engineering with all their considerable resources can do that. I'll drive them, see how they do, and refine them.

Carl Fausett

Kibort - I went back to my books to find that term you brought up - "motion ratio". It just didnt sound right.
Found it in my books... "motion ratio" is spot-on and correct. It was my memory that was faulty.

Some quick measurements of the early 928 lower front swing arm (mine is a 1978) shows that the lower front arm is 12" (+_ .25") from center of link to lower ball joint; and the shock is mounted 6" from said same center of link. For a motion ratio of 2:1

In other words: 6" of wheel travel will yield 3" of shock travel.

Just an FYI

SeanR

I love these threads.

Carl, nice thought, but Greg has brought up a bunch of stuff a lot of us were thinking when you posted it. If you don't think moving the pivot point of the shock an inch or three higher isn't going to make that 'mount' move, you are crazy. Hope it works out, but I've already told one customer today that there is no way in hell I'll install that set up in their car. Not only my *** on the line doing so, it would come a back to bite you also. They are free to buy it though.

GregBBRD

Seriously?

You are now privy to my books and know who pays for what and when?

Amazing!

FYI, the customer who's engine I developed that system on paid for zero engineering time, zero labor, and only paid for the parts used.....four months after the system was done....so I could throughly test it. Quite a good deal, for him. He's very happy.....as all of my customers seem to be. I've since sold several of those "kits" to address this problem and they all work very fine, with everyone very happy that they are no longer blowing up their engines and don't have a single drop of oil in their intake system. That sounds "fixed", to me!

Thank you for promoting this, for me!

Without redesigning the block and the return oiling system, like Ford did, on the Coyote engine, I did fix the problem. The engine can be run at 7,000 rpms without oil build up, in the heads. I'm not "limiting" the oil to the heads, which will cause more damage than good....witness the 944S2 engine (with the oil restictors) which "snatches" the chain tensioner off of the head. You might note that the 968 engine doesn't use the restrictor, because Porsche found out that the restictor provides inadequate oil supply and ruins parts.

I've currently got 12 new products under development....and no one has paid a single cent for any one of those pieces....and will not pay for them, until they are done and thoughly tested.

I personally think that you really should test things before you sell them....especially given your track record of things that don't work....but that is your business, not mine.

BTW.....you just personally "attacked me".

Something which I have not been doing, to you.

There are several other questions on this thread that you have not addressed. Instead of attacking me, why don't you work on those questions?

lowside67

If the stock length of the front shock is 19" fully extended, why would you spec one that is longer than stock knowing that the car will be operated at a lower than factory ride height? In theory, you would want a shock that has the same or similar stroke to stock with a total body length shortened by the desired reduction in ride height multiplied by the motion ratio.

Mark

brutus

You might wish to correct the absolute misuse of the term "suspension travel" in your initial posts since it ALWAYS is measured at the wheel or axle if you prefer.
With a bit more study you might have recognized that the bottom mount for the front shock should have been moved out closer to the ball joint because as it is now the spring rate becomes regressive as the arm moves above horizontal which is worse when the car is lowered. It has to do with the arc that the spindle moves through and as the shock is at more of an angle. Porsche using the large diameter springs was not able to move the lower shock out any farther and for a street car in normal driving it works fine.

Bill Ball

Well, I don't know if you're addressing my observation and concern. You know I'm not one to criticize someone else's work, especially in public. Lord knows I couldn't put together something as ambitious as this. However, what I see here is a variation on the problem seen with the tiedown. Having the mount body locked to the LCA so that it moves relative to the pin and bushing, with just a urethane bushing expected to take the beating, seems to be asking for trouble. If you observe how the stock mount works, there is no friction between the mount, its bushing and the pin - they move together. Take it as a brick, but I'm making an observation that is a corollary to what happened with the tiedown, which Jeff and I were somewhat key in reporting. If I am wrong and you have made some provision for this in the design, then great. Everything else looks good to me.

Vilhuer

Don't mean to take thread to off topic but is this known that reason for leaving valve out in 968 was problems in 944 S2 head? Other option could be 968 Variocam just needs more constant pressure. Though there is definitelly something going on in S2 heads as same problem has been seen in small local population more than once. One car is currently geting new head.

As for the product in hand. i agree with Greg and others that introducing additional joint at lower rear will cause problems. One of the two needs to be made solid.

puyi

I usually avoid to argue on that type of thread because it usually turn as fight thread.
But I can't let you tell that sort of argument. I have Bilsteins shocks on my track car that have been revalved for high rate spring. It is the way it has to be done because you can't do it in other way. Koni's could be great but it is sure that they can't support 2000 Lbs springs even if you can adjust compression ratio.
The fact is that the bilsteins set up can be revalved as you want, when you want and with plenty of supplier able to do the job. None of them said they can do it on Koni's.
The fact is that my track car compete with over 928 that has adopted your koni combo. The results is : my set up has been recognized as the most valuable!

For the stuff presented here, I see things very similar to what has been done on anderson car's, but it seems to me that your stuff seem to be similar but is really very far from it. I would add that the andersson's specs are proper to his car but i'm not sure is suitable for other's.

puyi