GregBBRD

I'm 100% certain we can help you with your suspension.
We are a 928 exclusive shop which specializes in all aspects of the 928, from routine service, to outrageous restorods.....and everything in between.

We undertook a huge effort in suspension development about 5 years ago, in order to make these cars "safe" when the horsepower doubles or triples.
Our emphasis (except for pure track cars) has been to improve the NVH of the stock vehicles.
The result is that we have about 5 different variants of suspension systems available, along with all of the required data for ride heights and alignments.
In short, we've got a huge "head start" on the reality of 928 suspension than anyone else, we are aware of.

A parts supplier will sell you whatever shocks they might have, on the shelf. If "rear Konis" suddenly come into existence, he's going to tell you that is the "hot ticket".
And interestingly enough, the "community" will try to convince you to do exactly what they did....because that is human nature. And everyone wants to think that what they used must be the "best" (which might be possible, depending on their goals.)
We, however, have virtually every variety of replacement shocks (even custom made high performance shocks) and have dyno tested each and every single variety.
And we know exactly what components "complement" each variety of shock.....because we have tested all of the different combinations.

We are very "private" about what we do for suspension and in our high performance engine/transmission programs.
We have had huge issues with people coping our products. No longer.
While I may talk in general terms about various aspects of suspension, I'm never going to hand out a blueprint to the Internet.
Plus, the difference between the various years of stock components turns out to be somewhat comfusing.

A personal phone conversation will eventually be required. I'll need to know what your desires are; stock stiffness, slightly higher stiffness, ride height preferences, what wheel and tire combination you are running or plan on running.
I can tell you what each different variety of shock offers, in terms of actual dyno numbers....and why you might pick one or the other, once I understand what you are trying to achieve.
We stock "mountains" of various suspension bushings; many stock pieces and several alternatives for use in particular areas.

If you are interested, let's start with a Email "hook-up" and basic discussion. (GregBBRD@aol.com)
Because we are so insanely busy, getting "past" Mary at the front desk in very difficult.....I simply do not have the ability to answer 20-30 different "how do I fix my 928" questions, each day.
"Secret" passcodes make this easier.

GregBBRD

It is certainly an interesting shock, in the internally adjustable configuration.
The internally adjustable portion only adjusts rebound. Compression is not adjustable...Konis sets that..
And the compression portion is more than 30% softer than the stock Sachs/Boge that are currently available.
The rebound adjustment goes from softer than a stock Sachs/Boge to...absolutely stupid.
So, depending on how the rebound is set, a Koni can be much softer than a stock Boge.

Koni's really need to be converted to externally adjustable shocks....especially on the bump, for anything but "really soft" street use, with stock springs. (And converting them to externally adjustable prices them into the "custom shock" price range.)
The shocks are completely inadequate for controlling an Eibach spring rate....there's simply not enough compression to be able to do this, at any ride heights above 140mm.
Fortunately, since the Eibach springs lower the car, you are likely riding around 24/7 on the bump stops (below 140mm), which makes the shock basically inert in compression.

The non-digressive valving (very old school) is actually tolerable on a 928, because of how the spring and the shock are mounted on a 928.
Additionally, since the Konis are not gas filled, the "seal drag" (significant issue) is less than any of the gas shocks.....which makes them even softer.

I would submit, that if you handed me your car and said: "Do what you do", you'd be completely blown away....to the point where you'd think that I handed you back a completely different vehicle.
Lower NVH, with (at a minimum) 40% easier/better car control (at the 100% limit of the tires), with the inability to find any limits/evilness at 80% of the tire limits.

We're absolutely doing "magic", here.
Amazing what is possible after 5 years of constant development and testing!

Bigfoot928

It's always magic when you don't have anything to show.

Speedtoys

Go buy it. It's just a keyboard warrior Email away..

Bigfoot928

that's the real magic. suckering people to buy non 3rd party tested vaporware that no-one has seen. most con artists have better people skills.

GregBBRD

And, truthfully, that is really the only thing that matters, especially if you are just cruising around in your 928. You like it. It works, for you.
And I've got hundreds of clients who are exactly the same. They never "challenge" the handling of their 928, so tires and suspension make very little difference to those people.

The reality of the 928 front suspension, without any modification, is that the bump stops begin touching at 145mm. The bump stop becomes such a significant part of the front suspension, by the time the suspension travels to 140mm (through even mild corners, when the cars are set to 150mm this occurs), that whatever shock/spring in the car becomes a moot point. Crank up the rebound (on a Koni) and yup, it will feel stiffer, but only because of the amount of time that it takes for the shock to return, before the next bump occurs.

We are different, out here.
Lots of 928's and other "high end" vehicles play canyon racing, every weekend.
We've got an endless supply of these roads.
Roads that are of poor quality....lots of potholes and repairs, but lots of corners.
The point is, that once the "red mist" comes out, driving through curvy roads with other similar 928's (and other hotrods), most people begin to alter what "they like" and want it better.
That's what we do for engines, transmissions, suspension, brakes, etc.

I've got custom suspension pieces which will begin utilizing the bump stops at 100mm front ride height. They get significant at 80mm. In this case, we are using the bump stops to keep the oil pan from rubbing on the ground.....not as some unknown variable rate part of the suspension.
Try to remember that Porsche put that bump stop in at that height, to ensure that all 928's understeer when turning!
And the more aggressive one approaches a corner, the more the bump stop becomes part of the spring rate, which increases the understeer.
Perfect, idiot proof design, by Porsche. Never any chance of oversteer (which 98% of American drivers would not know what to do with.....unless they learned to dive on a early 911.)

Once that bump stop is no longer sitting at 140mm, the entire requirements of both the springs and shocks completely transforms.
These pieces, suddenly, become what is actually determining how the car handles.

GregBBRD

Moving away from the usual collection of trolls (not you, John, that was just a fun discussion, for me), and back to the OP's request:
We have the pieces and the technology to deliver you whatever you desire.
You tell me what you want...and I can nail it, first time.
No guessing.
No selling you whatever I happen to have in stock, like other parts people.

You want to talk to someone who has an early car, which we transformed?
Call Alex Palevshy at OOO magazine and find out how his '79 handles and drives.
He's a talented driver who knows the fine details of how a car should handle.

icsamerica

Insanely busy not not too busy to look for "hook ups" out on the internet? Doesnt add up but no suprise.... unless... it's magic !

GregBBRD

Hmmm.
And another troll pops up....
No secret that I can't spend 10 hours a day, on my feet, any longer.
I'm 71 years old.
So I do get a lunch and a couple of breaks, in which I try to help people who ask for help.

And not that you need to understand/run our business from afar, Mary putting pieces into a box isn't remotely the same as the workload in the shop.
And the pieces I need to modify are done and on a shelf.

GregBBRD

I'm not sure that I have ever approached anything I've made for my 928's in terms of making a profit..
That has never been a goal...it's not ever even been a consideration.
I do this stuff, because I have the intelligence to make things better and get I bored, if I'm not thinking about something special/different.....always have....since I was a child.
My son is way different: "Once you are gone, we won't be selling or offering anything not stock, to anyone, outside of the cars in our shop."

Way too many hours invested, in virtually every single product I make, to ever begin to get even.
(Although I thought, for sure, that I'd get rich selling special sockets for control arms, at my cost......(Fvck you, trolls!)
There's no doubt that I'm basically a frustrated mechanical engineer, machinist, and perfectionist hiding as a mechanic.

Bigfoot928

don't forget magician.

Bigfoot928

I have a question. If all of your "magic" is so ground breaking, and so genius that experts in the field are enlightened, why don't you file a patent, trademark it and then show it and sell the crap out of it? I mean if you are the only guy on the planet that could figure it out and design it, that should be easy and it would protect your designs. You could do that in less time than you have beating your own drum on here and berating others for "stealing your ideas". You claim to have an attorney on retainer (remember those times where you threaten to sue people for libel, after you print up the threads with their transgressions?)
I'm sure it would save you time and money so you could get caught up on the years of work that you have backed up at the shop.

GregBBRD

Some very valid points, which we have studied and discussed, with others, including legal.

First off, two different kinds of attorneys.

Secondarily, I'm not actually "inventing" suspension pieces (other than some very unique/custom mounting pieces), but rather using a unique mixture of pieces, in a unique way. (It's not like I "invented" magnetic shocks or something trick like that.)
​We're not sure what I've done is actually patentable, in this day and age, plus any simple change could be considered to be different and not violating a patent.

Thirdly, money has never meant much, to me. For me, the thinking, the enginnering. the fabrication, and the development are what drive me and satisfy me.

Last of all, engineering, development, and fabrication are fun, but the proof was in the testing. Although, the math and the logic were fairly "solid"...lots of things which appear to be "solid" end up in the trash can, when tested.
The first of the prototype pieces (and there were several variants) I hand machined, in the shop. After fitting and hours of initial suspension manipulations, in situ, I was confident enough that I had four sets of pieces CNC machined (but even those pieces gradually got/need some changes.)

Real life testing was a very nervous time. Yes, we had driven the car around on the street with the stock GTS tires and wheels, but you never really know, what you think you know, until you screw on 11" front and 12" rear wheels with super sticky "state of the art" slicks and go attack some corners.

Luckily, Thermal has a couple of full time professional race car drivers and they drove the car, in anger, after the owner had driven it. They had some suggestions for shock adjustments, which helped dial the car in.
We also made several changes to dial in the camber, right there, at the track, which is something I always had to do, whenever we raced an RSR at a new track.
We brought back the car, to the shop, two times and "stepped on" the spring rate, substantially, both times. Once that "bump stop", which goes from zero to infinite spring rate in about 25mm of travel, is no longer a factor, main spring requirements go up, dramatically. However, without the bump stops being active until the tires virtually hit the underside of the wheel wells (we did have to increase them to keep this from occurring when there were lighter springs on the car), the handling of the car becomes very neutral, throughout the entire suspension range (which was one of my goals.) Get the front and rear spring rates to compliment each other, and suddenly an understeering mess of a 928 becomes a very tidy "minor" throttle steering car, as it drifts through corners.


Right now, It's better to limit this particular level of suspension (extremely "high end") to vehicles that are in our shop and in my basic control, when they leave. A Non Disclosure Agreement works good enough, for now.

And much like a set of "Singer Headlights" people can get a set, with a car, if they want that level of pieces.

(Our next step, for our official test street car, is to put a version of this suspension (with much lower spring rates) and go attack the canyons above LA.)

Thanks for the opprotunity to have a "civil" exchange of thoughts!

The Forgotten On

If you need a reference for speed through the corners of Las Virgenes Road heading inland from the coast of a 928 on stock suspension with wider tires I can give you numbers.

I used to commute it daily in my 81 and 89 for my old job.

Lets just say you can exceed the speed that most "high speed" crashes are reported at comfortably. 2 AM is a weird time in the canyons...

soontobered84

Poor Streetsnake!

We have totally hijacked his thread about putting together a suspension package for his car. I believe he was maybe needing new shocks and possibly springs coupled with some other things like front spring adjustment and we started posting tales of magic and suspension dynos and collegiate level suspension development teachers and professional drivers. I don't believe his intent in starting this thread was to re-invent the wheel or any other part of the 928 suspension, but to just get an honest answer about what is necessary and commercially available to upgrade his possibly original suspension.

Now then, can we get back to the discussion about retrofitting a Delorean flux capacitor to a 16 valve 928?