Options for ECS struts and other concerns

[2fnloud]

I was asked to bring this out of the PM system and make a thread for all to see, so here it is directly pasted from the PM that I sent to DG.


DG,

Thank you for the reply,

I am definitely looking for more than "cosmetic lowering". On the flip side I am not looking for what Rakuny is trying to accomplish.

Brief story:

I happen to have a 1994 Stealth R/T TT Hennessey tuned stage 5 3s, The Hennessey part is cool, but I know that he barely scratched the tip of the iceberg in unlocking a 3S's potential. So combine that part of the car's history with the fact that the car only has 30,xxx original miles....I have a BEAUTIFUL example of the 3S platform.

My Goal: As I improve the car's performance, be it engine, suspension, breaks. Is to keep every function that the car came with. For example right now the car has the HKS D2 exhaust. In doing this the Active Exhaust was removed. My solution when I add my Stillen D/P is to also install an electronic cut off valvethat is wired to the A/E switch, thus bringing back the A/E feature of the car.

For what it is worth, 3S gatherings are probably the only events that I will track the car.

So now understanding my car and my goals, you can see that a non-ECS strut is not an option for me.

I would be willing to corner weight my car, honestly had to read up on what that was exactly, My assumption was correct on how you weigh it, just had no clue how you compensated for it, still kind of confused. Are you slightly raising / lowering the height of the C/O lspring perch to shift the weight around? That was the impression that I got after reading the article.

Also in your reply about OD of the shock matching Bilstein or Koni, do that make a insert that is compatible with the 3S ECS system?

Finally, you mention of the upper spring perch, I am not following. Granted all my research at this point is what others have done vs. what I have done, so if I tore into the project I would probably know what you are referring to.

Anyways the information shared on the website Stealth316 He made no reference to having issues with his "upper spring perch. The only thing I see that he didn't do but should of, was to install helper springs to keep the C/O sleeve system in a load while the car is the air be it on a hoist or from extreme cornering. Is there anything else that was over looked that you see?

My other concern is the spring rates that he listed for the GC springs that he used and what he plans on using. With my limited understanding, and I do mean limited, I was under the impression that there is a balance between a struts bound and rebound rate and the spring that is mounted to the strut.

At what spring rate does the spring become too high for a ECS strut properly dampen? or is my understanding flawed?

Again thank you for your insight.

[DG]

Corner weighing: what you are doing is changing how much load is carried by each tire by changing the amount of spring preload on each corner - effectively, you are changing how hard each spring is pushing up on that corner of the car. This is done to attempt to ensure, as much as possible, that dynamic weight transfer affects the car equally in either direction. On a car whose CG is offset, either front/back or left/right, you can't get there from here, but you can at least prevent (or reduce) the amount of fore/aft change that happens with left/right load and vice versa.

More info here: Autocross to Win (DGs Autocross Secrets) - Corner Weights (http://farnorthracing.com/autocross_secrets11.html)

Aftermarket shocks compatible with ECS: almost certainly not - at least, not off the shelf. The ECS shocks are basically single-adjustable, rebound bleeds with a motor attached to the adjuster. The motor is synchronized to the adjuster so that it can set the shocks on full hard, full soft, or an intermediate setting. It really is a VERY simple system.

In theory, either a Koni or a Bilstein (fitted with their new adjustable shaft) or even an Ohlins or Penske for that matter, could be adapted to the ECS. You'd have to see just how much the rotor turned the adjuster for each setting, and you'd need some sort of adaptor made to fit the motor drive interface to the aftermarket adjuster interface. Then you have to tune the adjuster itself to produce the forces that you want at the settings where the motor is going to turn it.

Doable? Yes. Feasible? That's a lot of engineering for a super-niche product. You won't be able to sell any because it will be super expensive and people balk at paying money for suspension (that's how Megan, JIC, Buddy Club, Tein etc stay in business - people will happily buy shit if it is cheap shit) You won't get a shock manufacturer to step up and build it for the same reason. So you'll have to do it yourself....

I wouldn't do it, myself. But then I also understand that the 3S is a GT car, not a race car, so I'm less inclined to go down that rabbit hole.

The normal reason for fitting stiffer springs is that the tires are so sticky that lateral G capability is much higher than the car was designed for. Accordingly, the resultant roll angles get much larger and that drags the suspension around with it and pries the tire contact patch off the ground. Along with this, race cars are usually so low to the ground that there isn't much room for suspension travel so stiffer springs are needed to keep the chassis off the track surface.

Neither of these apply to a street car, even a street car that sees track use, assuming it keeps the street tires. You just aren't going to generate race car levels of lateral G, nor are you going to be an inch off the ground, so you don't need race car natural frequencies. Keep in mind that it is the rare street car that can hit 1.0 lateral G. My race car would see 1.7G peaks and could sustain 1.35-1.37. You aren't in that business and never will be - so don't worry about it.

Keep in mind too that the OEMs design the car to work both with a 155lb driver and a couple of gallons of gas, all the way up to four American passengers with a full tank of gas and a load of luggage (I wonder if there is an SAE standard for a typical max passenger load?) The car will be optimized for a specific case but needs to be acceptable over that entire range - that's like a 1000lb weight swing, with the according changes in location of CG. That useful range is why the cars sit so high unloaded, and why more modern cars have fenders that hide the gaps when unloaded. If you choose to optimize for a more specific case, you do so at the expense of some of this operating range.

That same wide operating range is what makes the ECS option such a good one - as long as you keep the changes reasonable, the ECS will still work reasonably well. The more extreme you get, the more likely you are that the design envelopes for car and ECS will diverge.

The upper spring perch on OEM cars is usually designed to fit a pigtail spring, so there is a rubber (or steel) spring socket that fits a pigtail. Race car standard springs are ground flat, so now you have to fit a flat surface into a non-flat receptacle. Depending on the actual design of the spring perch, this may or may not be a big deal. I haven't disassembled one (I have ECS, so no need) so I don't know specifics. But I've done enough cars to know that fitting the coilover sleeve is the easy part, it is the upper perch where the devil lurks.

Similarly, I've never dynoed an ECS shock so I don't know the specific rates for which its operating envelope will cover. I have studied the Mitsu docs on how it works, so I know it is a rebound-only system (Mitsu publishes typical shock dyno curves at each setting, but with no units)

My honest advice to you, given the nature of your car and how you intend on using it, is to keep the OEM ECS and use a decent quality lowering spring like an Eibach or an H&R to compensate for wheel gap. Then, if the thing is still rolling too much on the track, pick up a slightly thicker front roll bar and install it for track days, and call it a day.

That's my plan. I have no need nor desire to go down the coilover route.

If I didn't have ECS, I'd do Bilsteins, which makes doing coilovers trivially simple in the rear (with the one caveat of the upper spring perch) and maybe in the front if I really felt like burning money for no real reason.

And if I felt like racing the car.... I'd go lie down until the feeling went away. There are far better choices for a race car than a 3S.

DG

[J. Fast]

The front ECS strut has a 5" diameter spring that's offset. There's a pocket that locks the spring in place and keeps it from rotating or escaping the perch. A bilstein spring, GC or whatever, doesnt have that so you need to modify the perch to ensure the spring is in full contact 360 degrees at both ends. It's imperitave the force is equally distibuted at the upper and lower perch. Additionally, you have to ensure it can't escape. That's what it means to modify the perch: cut and weld, dissasemble and have perches machined, or fab something up on your own.

If you're sticking with the ECS and are doing a spring ONLY change you can use something like this as a guideline for selecting a spring. I't a Claude Rouelle Spring and Dampener Tech Tip.

http://www.optimumg.com/OptimumGWebSite/Documents/TechTips/Springs&Dampers_Tech_Tip_1.pdf

[DG]

http://farnorthracing.com/newimages/claude_seminar_small.jpg

:D

[B-Man]

And if I felt like racing the car.... I'd go lie down until the feeling went away. There are far better choices for a race car than a 3S.

DG

Curious what you'd race instead of a 3S in the same price range.


http://farnorthracing.com/newimages/claude_seminar_small.jpg

:D

:lo5l: And I have one of those from an SAE seminar, doesn't mean I retained any of it :P

I know you know what you're doing. I've used your site many times in the past couple years, but you seriously take all the fun out of owning a car :P

[DG]

Curious what you'd race instead of a 3S in the same price range.

Formula Ford. Older Formula Atlantic. Spec Racer Ford. Spec Miata. Anything NASCAR.


but you seriously take all the fun out of owning a car

Would you play golf with a hockey stick?

Would you play baseball with a tennis racket?

Would you go bowling with a curling stone?

Let me tell you, from experience, it is way, WAY more fun to show up at a gunfight with a gun than to try and hammer a knife into a gun. You go faster, sooner, and spend a tiny fraction of the money.

My DSM, at the point when I sold it, was a teensy tiny bit faster than an C5 Z06 Corvette in aggregate, and in the right circumstances (rain) could hammer the living daylights out of it. To get it there, I spent probably three times as much money as I would have spent had I just bought a Z06 and been done with it AND I would have won more races.

Let me put it this way - I would have had every bit as much fun and spent as much money had I bought three Z06 Corvettes and set two of them ON FIRE as I did hammering that DSM into a race car.

And a 2G DSM is a MUCH better starting point for a race car than a 3S, by virtue of a much better suspension, starting off much lighter, and having cheaper (read: less expensive) parts overall. That is, of course, two slightly different flavours of "turd"....

If you want to spend money and time on a 3S because you like the car and you want to see how far you can take it... hey man, knock yourself out. People soup up lawnmowers fer crissakes, who am I to throw rocks at you for the 3S. But if your intent is to go racing so you can WIN, then you need to get over the "platform loyalty" thing and go looking for simple, cheap, popular, and fast.

Race cars are TOOLS, not fetish objects. They are ultimately disposable. If you are not in a position where you can light it on fire and walk away, then it isn't a race car.

I got caught where my "fame" (small "f". Really small "f") was tied too closely to the platform. All my sponsors were DSM guys, and I could not afford to walk away from them. So I had no choice but to turd polish like a madman to keep up with (and ultimately defeat) the M3s and S4s and Supras that were the big dogs in my series. I wanted nothing more than to jump into an M3...

I would spare all y'all that if I could.

DG

[B-Man]

Formula Ford. Older Formula Atlantic. Spec Racer Ford. Spec Miata. Anything NASCAR.



Would you play golf with a hockey stick? Yes

Would you play baseball with a tennis racket? Yes

Would you go bowling with a curling stone? OMFG Yes

Let me tell you, from experience, it is way, WAY more fun to show up at a gunfight with a gun than to try and hammer a knife into a gun. You go faster, sooner, and spend a tiny fraction of the money.

My DSM, at the point when I sold it, was a teensy tiny bit faster than an C5 Z06 Corvette in aggregate, and in the right circumstances (rain) could hammer the living daylights out of it. To get it there, I spent probably three times as much money as I would have spent had I just bought a Z06 and been done with it AND I would have won more races.

Let me put it this way - I would have had every bit as much fun and spent as much money had I bought three Z06 Corvettes and set two of them ON FIRE as I did hammering that DSM into a race car.

And a 2G DSM is a MUCH better starting point for a race car than a 3S, by virtue of a much better suspension, starting off much lighter, and having cheaper (read: less expensive) parts overall. That is, of course, two slightly different flavours of "turd"....

If you want to spend money and time on a 3S because you like the car and you want to see how far you can take it... hey man, knock yourself out. People soup up lawnmowers fer crissakes, who am I to throw rocks at you for the 3S. But if your intent is to go racing so you can WIN, then you need to get over the "platform loyalty" thing and go looking for simple, cheap, popular, and fast.

Race cars are TOOLS, not fetish objects. They are ultimately disposable. If you are not in a position where you can light it on fire and walk away, then it isn't a race car.

I got caught where my "fame" (small "f". Really small "f") was tied too closely to the platform. All my sponsors were DSM guys, and I could not afford to walk away from them. So I had no choice but to turd polish like a madman to keep up with (and ultimately defeat) the M3s and S4s and Supras that were the big dogs in my series. I wanted nothing more than to jump into an M3...

I would spare all y'all that if I could.

DG

Aha! I got you to say it.

I think that's what most people need to see. Find a setup that fits your car/needs. All of this work you're talking about is to get that last 10% out of a car. I'd much rather spend the $1200 on 'crap' and enjoy the car at it's 80%. I'm not trying to beat Z06s or win series (although that would be nice). I think most of the people here are in the same boat.

I find my car to be more of a learning exercise, and I want to make the mistakes like buying shit suspension to get a feel for what's good and bad.

My car actually is pretty disposable :lo5l:

Remember people, we're all free to have our own opinions :p

Alright, I'm off my soapbox. I'll let the two suspension threads go uninterrupted.

[DG]

I'd much rather spend the $1200 on 'crap' and enjoy the car at it's 80%.

The big problem with suspension is that we aren't talking about the difference between an 80% solution at the low end and a 99% solution at the high end.

The "crap" that is JIC, Tein etc etc is actually much WORSE than a straight up OEM replacement shock.

It's not like it is with, say, turbos, where you can do 13G and get a nice little upgrade without a lot of tradeoffs, as an intermediate step to the GT50000 Disco Rutabaga or whatever the hot single turbo is these days. Crap, when I talk suspension, really is CRAP.

If you want a simple upgrade, a set of OEM replacement shocks - by virtue of being newer and so not worn - plus a set of lowering springs, will do the job.

Want something a little better? Use the OEM replacement Bilsteins, with the OEM spring adapters they ship with, and a set of lowering springs.

Want coilovers so you can do corner weighting? Now you're going to start down the rabbit hole. Now you do OEM shocks with the GC sleeves and worry about the upper spring mounts - or you do Bilsteins with the Bilstein sleeves (which may require a new snap ring groove) - and you worry about the upper spring mounts.

Still not good enough? Retrofit ECS (and figure out the spring mounts) or start a Bilstein take-apart conversion (and figure out the spring mounts) etc etc etc.

There is no real off-the-shelf, buy-it-as-a-kit, intermediate-upgrade option.

DG

[B-Man]

I have a hard time believing out of all the people to buy off-the-shelf coilovers, nobody but you say they perform worse.

[DG]

Because people are not well equipped to be able to properly assess them.

I cover this in A2W.

DG

[DG]

Here's an example of what I mean.

I was a Penske dealer. The boss's C5 had Penskes on it; we developed a coilover kit that basically eliminated the transverse leaf spring and the stock shocks and replaced them with Hypercoils over Penskes. As well, I got rid of all the rubber bushings in the shock assembly and replaced them with spherical bearings. Depending on how this kit was optioned, it would cost you somewhere between $1500-$3000 PER CORNER - and WAY more people opted for high end over low end. So $12,000 for a full set of shocks.

Now when I did my measure and model of the C5 suspension, the OEM springs were pretty much on the money for rate, and the OEM shock was damn near perfect - and the later version of the OEM shock WAS, for all intents and purposes, exactly what my model suggested. The OEM shock was also super-repeatable and didn't fade; so much so that I painted one bright orange and kept it with the dyno as my calibration shock. Every time I fired up the dyno, first I'd run the calibration shock to make sure it read the same as last time, and if ever during a run a shock started reading something I thought was wonky, I'd pull it and double-check the dyno with the calibration shock to make sure the problem wasn't either the dyno or me.

Our kit needed to come with a default setup. Some customers would provide specs, but most just wanted a bolt-on, ready to go kit. So our off the shelf, default configuration came with with springs rated the same as the OEM springs, and the shocks were very carefully matched to exactly duplicate the OEM shock.

Now think about this. You just dropped $12,000 on a set of shocks, and what I sold you was effectively the exact same thing as what GM provided you off the factory floor. There was a slight weight loss with my kit (the coil springs weighed a little less than the composite transverse leaf) and I eliminated all the rubber at both ends of the shock, which improved small movement sensitivity a fraction, but these are small-order things. For all intents and purposes, my shit was IDENTICAL to the OEM stuff.

(true, what you bought with my stuff was capability - any spring could be swapped on in minutes, and the Penskes had huge adjustment range, where the OEM shocks were non-adjustable. But as shipped, performance-wise, identical)

I was totally up front with customers about this. We needed a default setting, and if the default was the same as OEM, then you had a point of reference you could build off of. There was NO attempt to defraud or otherwise hide this - in fact, I shipped a dyno plot proving that your shocks matched my reference OEM shock)

Customers LOVED these shocks. Rave reviews all around. Not ONCE did I have a single complaint and I shipped about a dozen sets. And here's the kicker - most never touched the knobs or changed the springs. Some racers who fit R compounds went stiffer and matched the shocks to the new springs, but almost everybody who had street cars left them as shipped. One guy I remember in particular told me he had played with the knobs, hadn't found anything he liked, and went back to my default setting.

Which, I remind you, was the same as OEM.

Part of this lesson is that GM really did a fantastic job on the Z06 suspension... but the other part is a lesson in the power of placebo effect, and the cognitive dissidence that comes with having spent a shitload of money on something shiny.

DG

[j2k4]

I will continue to read everything DG has to say about suspension generally, and the 3S platform specifically, but I will take away from this latest set of discussions the conclusion that stock (functioning) ECS/w lowering springs is the zenith of affordable options for our cars.

While I definitely wanted to drop the car a bit to deal with the almost "lifted" appearance of the OEM setup, I feel the springs I installed give me what I desire; going lower for it's own sake has the sole effect (in MY opinion) of pointing up the mismatch between the wheel-well arc and the tire - the lower you go, the worse it gets.

I also subscribe to the idea that genuine race stuff will almost always screw up the real-world experience - as DG has pointed out, the redeeming aspects of these cars all have to do with it's GT flavor; I learned this right away, as my first experience with my car was the 1400-mile trip home, in the worst frigging snow storm I have ever driven in - I identify with that deduction 100%.

So, I am not inclined to try to make the car something it is not, but rather do everything within reason to enhance it's ability as a GT car.

If I went down another path, it would likely be to emulate/duplicate Austin's or Matt's efforts, but while I want to have several more of these cars eventually, I am not inclined to throw cubic dollars at them in unrealistic endeavors.

[J. Fast]

Not everything he says is the "end all / be all". There's general rules of thumb, and testing. He's never done ANY testing on 3/S so most is speculation based on professional experience and supporting other platform R&D.

He paved his own roads which is what my camp has been doing for some time which is why I have to disagree you can't make a 3/S a race car. No one's ever tried but PRM and for some strange reason they do really really well. It's quite possible to build a very very competitive car for less than the price of a Z-06, one that will outperfrom a Z-06 in handling, straight away speed, braking, and aero. This year (3) 3/S cars will be emerging from the Rocky Mountain Region camp. All of them will be competitve race cars. I'd hate to admit what I'll have spent to build mine, but I will say it's less than 20K and it can be replicated in less than 90 days. If I put another 20K in it HOLY SHIT! Motec, Penskes, and a 4 corner AP Racing Brake kit = the end!

Anyway, stock ECS with a good ride height and frequency has good manners.

[j2k4]

Not everything he says is the "end all / be all".

Not saying it is - I wouldn't extend that status to anyone, including Ray, Matt, Chris, Von, or whomever else; I mean to say, however, that whatever any of them has to say has general relevance, and it just happens that I have read lots of DG's stuff.

[J. Fast]

I know and have studied in depth the ride frequency ans full stock suspension. Even collaborated on a full on customizable ECS system. It was developed over 2 years ago. Allows independant or fully customizable suspension control suspensio. Manually overide to select soft, medium, and hard with programmable AI.

http://www.3sgto.org/f17/ecmcu-project-build-integrated-active-aero-suspsension-controller-systm-1765.html

[J. Fast]

Watch video... 3000gt Stealth Custom ECS Controller SW demo - YouTube (http://youtu.be/jwhfRh4F0P4)

Keep in mind. This is on a vehicle model and year that did not have ECS either. 98 VR-4

[j2k4]

I seem to have stumbled into big-dick competition.

Hey, you're all experts to me, so.

[J. Fast]

Not really a dickswinging contest but more of a reiteration and proof about how much support our platform really lacks. You have to R&D your own suspension parts because nearly everything off the shelf that isn't stock is shit. You either go full custom or you hybrid adapt the stock system.

[j2k4]

Not really a dickswinging contest but more of a reiteration and proof about how much support our platform really lacks. You have to R&D your own suspension parts because nearly everything off the shelf that isn't stock is shit. You either go full custom or you hybrid adapt the stock system.

All of that is perfectly clear - these cars had a rep as rolling grenades right out of the gate, and their following suffered for it.

The dynamic that has played out has pretty much been one of pure redemption, owing to a late-developing appreciation of what the cars were intended to be, as well as the efforts of the enthusiasts like yourself and DG.

I think that, oddly enough, the current level of interest is largely due to the fact they've been regarded for years as tremendously risky, maintenance-wise, which makes them affordable - cheap enough to sink the hook, but expensive enough after-the-fact to empty your piggy-bank.

Good thing they aren't ugly as well.

[DG]

I'd hate to admit what I'll have spent to build mine, but I will say it's less than 20K and it can be replicated in less than 90 days.

MY time is worth money; that labour ain't free.

Take one C5 Z06 in good condition (~$15-20k - not the "collector cars" that are starting to come out of the woodwork)

Fit 335R18 race tires with the appropriate wheels.

Stiffer springs to acommodate the massive increase in lateral grip. A set of Bilsteins matched to springs (could be coilover or not)

A set of Pratt & Miller T1 suspension arms (off the shelf spherical bearing control arms) to eliminate a set of overly squishy rubber bushings.

Open the exhaust.

Install an off-the-shelf cage, race seat, and harness.

Put in proper racing brake pads.

Less than a weekend's work. And that car will be stupid fast, mechanically reliable, and insanely easy to drive. It will have no bad manners, will accelerate, turn, and brake, and it will do it all weekend.

It has factory adjustable ride height and corner weighting. Tons of factory caster and camber adjustment.... basically 90% of the stuff you will spend fixing or working around on a 3S is already done right on the bone stock car.

The sweet spot in the factory camber and bump steer curves are at 1" lower than the factory ride height. It has near perfect weight distribution. It's just an incredible car. If it wasn't for the twin facts that 1. It won't haul as much shit as a 3S and 2. After fixing my boss's car about a billion times after he kept hitting a variety of solid objects I'm so sick of working on them that the very sight of a blue one drives me into a fit of rage, I'd own one myself.

Of course, then I'd probably disappear down the race car rabbit hole again and that is considered "grounds for divorce".... So I'll keep my 3S. ;)

If you have never driven one on a track, try it. You will quickly lose any illusions you have about what kind of race car a 3S makes.

And if you really want a life changing experience, drive a Ralt RT-4 or something similar.

DG

[B-Man]

I've driven a base C5 on what was basically an autox course. It was a little down on power, but that was probably because of age/wear. It was amazing, even in the rain it was so neutral and just went where you pointed it. If I could make my stealth handle like that, I'd be perfectly happy.

[DG]

If I could make my stealth handle like that, I'd be perfectly happy.

Ah, Grasshopper, you are walking the edge of enlightenment in the way of the race car.

The simplest, easiest, fastest, and cheapest way to make your car handle like that is to make your car a C5 Z06.

You wouldn't try and graft the 3S's best features (AWD and the extra cargo space) onto a C5, so what makes going the other way seem like a good idea?

DG

[B-Man]

Why wouldn't you try to graft AWD to a 'vette?

[DG]

For the exact same reasons you don't try and make a 3S into a C5.

DG