superstring

Hi All

I've wondered about this one for awhile now, so here goes.

People always ask questions about the "best" suspension setup. Of course everything's a compromise, but one solution mentioned a lot seems to be coilovers with fairly stiff springs and adjustable damping.

So, looking just at the "road use" side of the equation, given a set of coilovers with fairly high spring rates (eg. Leda B) and adjustable damping, if you "soften" the damping for the road, don't you just end up with poorly controlled, underdamped springs that don't perform nearly as well as a softer spring setup with properly matched damping?

It would seem to me that, unless one does a lot of track days, the optimum road setup would be the latter. Is the stiff spring/soft damping option really that good for road use?

Thanks!

ScoobySport (SdB)

Very analytical view.. and justifiably so.

Firstly, you are correct in your intimation that there is no such things "best set-up".

On the spring rates issue.. the holy grail of suspension / chassis set-up is lower spring rates. The lower the spring rate you can use, the easier life you give the tyres and therefore the more mechanical grip you get from them.

Unfortunately, it takes a hell of a lot engineering to achieve this. It's not just a case of different rates on the damping / bars, etc.

It is also absolutely true that if you have a hard spring, and simply reduce the damping (especially on a single adjuster) you will almost certainly end up with an under-damped set-up, which is a complete disaster on the road or track (not just the road).

Another benefit of softer springs is that it gives you slightly more flexibility in the damping.. this means that you have more useable adjustment available to you.

An "ideal" (there is no such thing, but bear with me) suspension set-up would be one that feels great on the road, but is very performant on the track also. This is generally considered to be impossible, but with the right engineering this is not the case.

As an extreme example, a tarmac spec WRC car is a pleasure in ride and handling both on the road and on the circuit. Most people would drive and think it felt really subtle and refined (it's a little noisey, but the drivers don't seem to mind that ).. you then blast the thing round a circuit and it feels compliant, powerful and firm. It's not active, and there is no trickery involved, it's just superb engineering.

All the best

Simon

911

Simon is dead right.
There is no reason why coil-overs HAVE to have stiff springs, the rate chosen is up to the driver looking for the 'ideal'.
It is all about getting the damping rate to match the spring rate for a given 'condition', ie road.track etc. this is why a road setting may not be 'ideal' for the track, and why the coil-overs are adjustable.
Finding the balance is tricky and needs a lot of experimentation.

Well sorted, the coil-overs can be compliant and a dramatic improvement on the stock compromise.

It can be achieved, and you don't need mega expensive units (though it helps)
911

superstring

Thanks for the replies!

Hmm...this is interesting, Simon. Would this be with the damping turned all the way "down"? Point taken about "superb engineering", but I remember Richard Burns once saying that WRC cars were horrible to drive on the road and didn't really come into their own until you were on "full attack"!

ScoobySport (SdB)

Agreed, as an entire car (not just the suspension - but the car as a package) they are just not designed to work on the road. The engines are lumpy, the clutches are heavy and agressive, the diffs are clunky and feel un-refined, etc..

The reason for the example however was simply that the suspension does not feel hard and agressive, it feels subtle, compliant and refined.

You can take off in a WRC car at 120MPH and cover seemingly impossible distance in the air only to land as though it had gone over a slightly steep hill. They can ride bumps with the same level of comfort as a drive down the motorway in a road car.

Many people go out and fit rock hard suspension to their car, crank the bars right up and set the damping so you need to leave a bus sat on the strut for an hour in order to get them to move through their entire travel. They drive this and think it's made the car incredible, purely because the car reacts immediately when they put in a steering input. The problem is that this reaction is only momentary and the performance of the set-up is a huge compromise away from actual grip and handling.

I'm not suggesting that the absolute ideal suspension set-up for the road would be the absolute ideal set-up for WRC also.. it was just to show that a car does not need to rock hard in order to handle and perform well on a track.. in-fact it is a detriment if it is.

All the best

Simon

superstring

Gotcha. Thanks Simon.

AvalancheS8

In Motocross, and also Downhill Mountain biking (which I take part in), the best performing dampers use a shim stack to give speed sensitive valving so that the bump damping can be quite heavy at slow shaft speeds but relatively soft at higher shaft speeds ( example). This allows the suspension to be set up to be well controlled on undulations and to cope well with landing from jumps (both relatively low shaft speed at the shock) but still absorb sharp edged bumps well (very high shaft speed).

Is the same kind of technology used on car dampers ? presumably a good set-up of this kind could offer good body control and steering response with fairly firm slow speed bump damping and have much softer high speed damping for good bump absorbtion.

ScoobySport (SdB)

Avalanche

Absolutely. Although this is very VERY rare for road cars.

It's an often misunderstood fact that bike damper technology is years ahead of that of cars.

In WRC, there are some very clever systems. First of all there is independent slow and fast bump damping adjustment, and in addition there are clever techniques such as precharging the damper with nitrogen to take out all the tiny vibrations and really high frequency inputs.

This is the reason why a top quality damper (such as the tarmac WRC example above) feels refined and a pleasure to drive, as a contrast to the hard non-compliant feel of most of the after market road car stuff.

All the best

Simon

IWatkins

Do I hear a suspension product launch ahead ?

ScoobySport (SdB)

LOL

That was announced ages ago mate

jgevers

Damping on race/rally cars and bikes proceeds at a very similar pace. Digressive or near digressive bump damping is becoming the norm in road cars as well now.

The problem with a lot of aftermarket 'boy racer' dampers is that bump damping is progressive with very little low speed damping. The rebound seems to me to be to hard. This hard rebound will give the uncomfortable jarring (the car is 'holding on to it's wheels' after compression). The lack of a high speed bump blow off can give some strange behaviour when hitting pottholes or bumps.

On adjustable dampers, quite often, an adjustable needle valve is used as fluid by-pass to soften rebound. Lack of a some sort of one-way valve allows oil to flow undamped in both directions. This normally equates to loss of low speed damping (until the by-pass suffers from fluid lock), both on bump and rebound, giving that horrible floating feeling when the damper changes from bump to rebound.

I could go on about all the design faults in aftermarket suspension kits, but I will just say: Just because a suspension set up feels quick, it doesn''t mean it is quick!

A well designed damper with a well developed shim stack will have compliance, will ride bumps and kerbstones well, create good traction and will have enough low speed bump damping to 'hold the car up' on turn in etc.

Just look at the P1 set up on the damper dyno to see what works! If you find that set up lacking in any way, just get the damper valving changed slightly to get what you want.

As far as I am concerned, this is the best value for money set. If you want better, the only way to go is bespoke from Penske, Proflex, Ohlins, Moton, Reiger etc.

The only 'boy racer' suspension that might work properly is from AST. This Dutch company is run by Piet Kreeft, a former Koni F1 engineer who does have proper experience and knowledge.

This just my opinion, as a former suspension 'enganeer'

regards

911

Most interesting!
As I use my Stiv3 for serious hill climbing, the suspention characteristics are more important than the 'BHP' side.
Cost always rears it's head, and I made the mistake of choosing nasty AVO damper/coil-overs.
Buy the very best(probably the most expensive) you can, and follow threads like these all the time.

I think the real trick is getting the damping to relate to the springs/car set-up/application.
Hill climbs are smooth but very twisty and very undulating with lots of on/off braking and accelleration added, and all in a very short time. The driver is very busy.

I have spent ages getting my AVO's sorted, but got good advice on the minimum spring rate needed. However, these rates need 80/60% (front/rear) of the damper settings to match the springs. Too high a rate and the dampers will never get in control of the spring movement = poor ride but most imporantly, poor driver control.

911

jgevers

In suspension design nowadays, the damper is an integral part of the vehicle dynamics. It is no longer just used to contol the energy from the spring. For instance, the damper is used to hold the vehicle up on turn in (low speed bump damping). If the damper is used in this manner, and roll control is maximised, I would expect you to run almost identical spring rates front to rear.

As for a previously mentioned 'pre-charging with nitrogen' this is normal practice in all monotube dampers, except emulsion type. If the gas pressure wasn't there, the damper would 'pull' a vacuum behind the piston/shimstack and immediately aireate the damper fluid when moved. Vehicle behaviour can be slightly influenced by different gas pressures eg. Porsche GT2 with dampers that normally run at 12 bar would be increased to 20!! bar at some tracks to make the car slightly less nerveous on long straights, allowing more driver confidence.

regards

ScoobySport (SdB)

911

First of all.. hill climbing is terrifying - you must be mad

Without question, the damping needs to take the whole package into consideration (and as jgevers said - modern top end practice is to do just that).. the challenge is that this is no easy thing to do. Plus.. the damping set-up then changes the rest of the package which means you could then go through all that and change it to match the benefits you've now found, then back to the dampers, etc, etc. It's fun, but time consuming and bloody expensive

Which makes the damping one of the most important parts of the set-up - if you can have such a thing.

---

jgevers

Why would you expect to run the same spring rates front and rear, and what would be the benefit of that?

WRC cars use twin tube dampers rather than monotube to increase accuracy of the geometry under load and reduce vibration.

All the best

Simon

911

Firstly, Hill climbing is bonkers, but at least there is only one brainless idiot on the course (me). Think of me at Shelsley Walsh this Saturday; try it in a 911...........

Secondly, We need to think about 'budget' struts, and not just high-end systems.
I made the mistake of fitting AVO units, not DMS or LEDA. The damping control seems crude and 'drifts' in my opinion mainly due to temperature, it is worst on the road rather than the short run that is Hill climbing (it passes by quickly if it is a white knuckle ride...).

It would be good if there was a real tech back-up/advice from the manufacturers, AVO were very weak, where I think LEDA are strong, at least they read this Snet!

Do you think thing get worse if you have adjustment in up and down damping rates?

Interesting debate, I'm no expert, but these things do make a difference 'on the limit'.
911

jgevers

Hi Simon,

What do you think the suspension frequency is with for instance 200 pound springs both at front & rear. I think you'll find that in order for the car to behave properly in theory, you will only need to go up about 5 or 10 pounds at the front to make it work. My guess (not calculated, just experience with different vehicles) is that for a smooth tarmac car with reasonable size roll bars and slicks the spring rates to be approximately 320 pounds front and 300 pounds rear. This will vary greatly with teh types of tyres used and type of track. A road Scoob will behave quite well with approximately 200 pound springs all round. If you are thinking in metric, just divide these pound figures by 5.6 to get metric.

By the way, most WRC vehicles use inverted MONO TUBE dampers with quite large diameter body & piston. I have never seen a twin tube damper used on a WRC vehicle. If you know more, please let me know, as I am very interested in how a manufacturer can make this work satisfactory?

Have a look at Penske, Reiger, Proflex, Bilstein and Ohlins dampers, as these provide most of the WRC teams with dampers. I think only Peugeot and Citroen use a French manufacturer with quite ingeneous designs (not twin tube).

I am sorry that I can not be more specific about the rates on Scoobs, but my work as a suspension engineer was for different WRC and circuit racing teams and I retired from this career almost 5 years ago.

regards,

Job

StickyMicky

i love techy threads like this

i removed my coilovers and i can honestly say that my car handles far better now, with new standerd stuff, then it did with 2k`s worth of jap coilover stuff

it did feel faster with the coilovers, but i know its faster without them, i will be selecting sumthing that is proven to work well with the standerd shocks, and not just sumthing to lower the body hieght

911

That's fair enough. This thread started with the 'ideal set-up' you have found yours!
I tolerate the AVO's and all the other suspension mods I've done along with them just to squeeze the best from the hill climb run which lasts about 50 seconds or less.
This is my 'idea' thank god we are all different.

Tech threads like these are great. It is good to read the theory/engineers and for me I drive on what these guys derive from their work.
Sorry to keep coming back to cost, but high end is not an option for the masses.
Several EVO 5 hill climbers run on dampers/coil overs with remote cylinders mounted in the hot engine bays, what does that do to the characteristics?

Most of us would like to see what the designers above think are the key desireable features in ciol overs, and why people see (feel) the uprated springs and production fixed rate dampers work better than stock? Is there more in the spring design to discuss than damping?????
911

ScoobySport (SdB)

Hi Job

The frequency is dependant on the load on the corner / end. This was the reason I asked why you would suggest equal (or near to equal) spring rates, as the assumption could only be made once you knew the weigh distribution of the car. I now think you meant near to equal frequencies, in which case, I agree completely (as a starting point).

It may be that we are falling foul of symantics on this also, as you may mean something different to me when you say twin tube / mono tube.

A twin tube system is one where the main load bearing element of the damper is external to the actual piston / spindle arrangement. In other words, there is a second tube which is outside the damper itself, and this tube takes the stress of the wheel, etc.

All WRC cars currently run a twin tube system, except ford who run a tripple tube system (which I know very little about - but effectively they have the resevoir in the bottom of the damper near the wheel).

Citroen make their own in conjunction with EXE-TC (in UK).
Peugeot make their own in-house
Subaru use Sachs
Misti used to use Ohlins, but now make their own
Ford use Reiger

911

great questions, unfortunately, I'm just about to go into a meeting, so I'll have to keep it really brief...

The reason is simply the way people are able to perceive the movements of the car.

For instance.. in roll, a human being is only *really* able to recognise the *initial* roll of the car and the rate at which it does this. You then recognise the *initial* yaw of the car as well, and have very little sensation of how much it rolls / how much it yaws.

So.. fit a hard set-up and this initial "feel" is agressive and powerful. It is very difficult for human's to recognise the actual resulting cornering performance of the car, etc.

Sorry for brief reply, I'll try to drop back later.

All the best

Simon

911

I can see this thread getting deeper!
When hill climbing, ie going too fast on a closed road, all manner of sensations occure(!).
On initial turn in the cars change of state is very easy to sense, the 'delay' to turn due to moments of inertia, tyre block tread 'suffle' (not slicks of course) and the damping rate to the springs reaction to the weight shift across the chassis.
As the dynamics build up, ie accellerating of even braking into/through the bend, the spring/damper relationship does exactly what you say, the driver looses a sense of what the car is actually doing, and you become a near passenger.
This is very accentuated in a 911 I hill climbed for 9 years, resulting in a coming together with a 100 year old oak tree at speed, with roll oversteer setting in, but quickly. I thought I was straight and going to the finish line!

The scooby is VERY different, slow to turn in and hard to keep all wheels on the ground.
This is my key interest here, my chassis is very modified but some bends are just nearly out of control/traction/ and very time consuming to let the car 'settle down'.

I'm off the tech point here, sorry, but I realy appreciate the technical input verses the drivers 'feel'.

Theory meets practice!

911

Steve vRS

Back to coil overs with ride height adjustment. Do they work by compressing and relaxing the spring or do they physically move the spring up and down with a constant length?

This thread came up at a great time for me. Is it possible to have a suspension set up that allows comfort on the road but can be stiffened up for the odd trackday?

Cheers

Steve

PS Sorry for lowering the techie content. I did vehicle dynamics as a course option at Leeds University and the above is beyond me

jgevers

Hi Simon,

We are talking about different things.

What you call twin tube is actually a inverted montube (a monotube damper upside down in a casing. The monotube damper can be run upside down because of the high gas pressure. When you see an inverted (looks like the damper has a very large diameter rod), the vehicle will have montube design dampers. This damping procedure was designed by De Carbon. An extra cavity is sometimes created in the casing for a cooling system. The external canisters are used to allow more space for the gas compartment as well as adjustable bleed for bump adjustments. Sachs multi adjustable race dampers have this bleed function placed on the side of the damper, very similar to an early White Power design. I believe that the ball/seat valves will have a tendency to wear out quickly in this design though.

A twin tube damper has an inner tube with foot valve with a piston running in it. The cavity between the outer tube and inner tube carries damper fluid as well. Gas dampers of this variety have low pressure inert gas above the fluid level in the outer tube or a gas bag inserted in the case of Spax. Most road cars have twin tube dampers.

As far as I know, most WRC, Formula 1 and touring car teams that proclaim to make their own dampers still use internal parts made by one of the prviously mentioned companies.

The suspension frequency can still be the same, even though weight distribution is different front to rear. It depends on the suspension dimensions and rates. I would expect a standard uk Scoob to have a theoretical frequency of approximately 5Hz. at the front? If you are developing a suspension package you will have probably calculated it, which will be lot more accurate then my guesses.


Hi 911,

If you have to run AVO twin tube dampers, you will probably have to play about with the shim in the footvalve to get enough low speed bump damping. Avo should be able to supply you with these. You might find that when you get enough low speed bump damping, the damper rod might bend. The side loading is quite high on McPhersons hence the reason for inverted dampers to spread the loading. I think the AVO rods will be a bit soft.

regards,

Job

911

Job, I think the AVO's are weak in many respects, and from my contact with the Co 2/3 years ago I have little faith in them.

As to ride height adjustment/comfort:

High end commercial units can have multi rate progressive springs, and i presume the variable damping to accommodate the rate rise which will be non linear?
Certainly, i have seen (with envy) Porsche units for the 'modern' Porsche with such springs (H&R I think). Never seen any for the Scooby in 2 1/4inch diameter.
The ride height is done simply by gapping the lower spring seat to the free length of the coil spring which is fine. The greater the gap the lower the car. In AVO's defence, their design does appear to have a very long stroke before bottoming. My Sti is 25mm lower than stock, and off-track in a hill climb is a bumpy affair(!) and I've never had bottoming out. Maybe this is why they do not provide bump stops!

I do wonder if I would get better response by fitting , say, Type C suspension with lowered quality springs, maybe all coil-overs are the same as the AVO's?

911

AvalancheS8

Assuming that the car has some sag in the suspension at ride height (the weight of the car at rest compresses the suspension) then it's not possible to change the length of the spring at rest.
If, picking numbers for simplicity, the spring was 300 lb/in rate with a free length of 10" and the force acting on it with the car at rest, just due to the weight of the car was 300 lb then the spring would compress 1", to be 9" long. This is irrespective of the upper and lower mounting points on the shock.
The usual way of adjusting ride height is by having the top of the spring resting on a screw threaded collar which can be screwed up and down the shock body.
So considering the spring above, mounted on it's shock, if you reach under the car and screw the collar up the shock body by 1/2" then the car will drop by 1/2" since the load on the spring is still the same (influenced only by the weight of the car) so the length of the spring under the load applied by the car at rest is still the same - 9". That means that because you have moved the top of the spring up 1/2" you have moved the bottom of the spring, and therefore the shock and wheel up by 1/2" with respect to the car body, so the car sits lower.
On cars which don't use strut type suspension there may be a ratio between the shock movement and the wheel movement if the shock is not mounted right at the wheel attachment point on the wishbone but otherwise it's just the same.
It's a common misconception that the screw collars at the top of the spring make the springing harder and softer, they don't that's a fixed property of the spring, they just raise and lower the car.

911

Agree with the last bit, but the screwed collar is on the shock body, at the lower point of the spring. the spring pad next to the top mount is static, and the collar on the body (at least it is on my AVO's.)
Thus, if you screw the collar down (towards the ground) the car will follow it.
911.

AvalancheS8

Fair enough, it can be either way. I guess in my head I was imagining a bike style shock which would be the other way. If you screw the collar towards the spring the car will rise, screw it away from the spring the car will drop - that should cover both situations.

StickyMicky

the JIC magic units i had on mine were a lot more advanced then that, the spring collar was only there to adjust the spring preload

the actual ride hight was adjusted by turning the entire threaded body which screwed and unscrewd the bottom brackets, which adjusted the ride hieght that way

its just a pity i ended up with the rock hard jap spec ones and not the US spec softer versions

911

Seems many people suffer from very stiff springs on the Jap coil overs so upsetting the one key quality of the Imprza, compliancy.
My 'specialist' who sold me the AVO's really screwed it all up, and Whiteline resolved the cars handling problems for me in the end. Their advice was spot-on.
911

ScoobySport (SdB)

sorry for the delay chaps, I'm in cyprus now so will be short of time intermitently for the next few days.

Job

Agreed that the frequencies can be the same front and rear (as stated in my previous post), but the frequency is a function of load and spring rate, which is the reason i asked originally why you would want near equal spring rates.

It is clear you know what you're talking about so I think we're just using different terminology.

For the benefit of all, the suspension frequency is a function of the spring rate, and the load on it. If you wanted to make a truly neutral car.. you could start by looking at the load on the front and rear axles, and match the spring rates to the percentage of load...

In other words... if the front supported 10% more weight than the rear, you could make the front springs (assuming wheel rate / spring rate ratio is the same front and rear) 10% "stiffer" to accomodate it. That way you have the same effective ammount of spring stiffness per kg front and rear.

If you then want to make the car naturally biased toward understeer (for example) you could soften the rear in relation to the front.

The problem is that this gets confusing, if a) you change the loads front and rear, or b) want to soften or harden the car as a whole without effecting this balance. So frequency becomes a nice easy calculation, as you can just lower or increase both frequencies by the same percentage, then use all your previous settings (in frequncy) to continue testing.

--

Spring rate / wheel rate. Something often forgotten (and something I hadn't payed enough attention to - until someone (johnfelstead actually) reminded me a few years ago) is that the wheel rate is the actuall important thing rather than the spring rate.

Depending on the geometry of the car, the wheel will have more or less leverage over the spring so the effective spring rate (or wheel rate) will be different to the pure spring rate.

---

911. The problem is that most damper manufacturers / designers spend their time working on the actual design of the damper, rather than looking at the car and working out what kind of damping is required. It's a fine line.

The best example to think of is the way humans interpret sounds, etc.
How many times have you been in a room with loud air conditioning, or a machine running, etc.. then it suddenly stops and you go "WOW! what a relief".

Before that, you hadn't noticed the sound.. and if someone asked you to tell them how loud the sound is (while it was happening) you'd struggle to even recognise it at first, let alone give them an answer. We notice CHANGES in out senses inputs far more than the current state of them. It is what makes us tollerant of pain, noise, altitude, etc, etc.

What good drivers are able to do is hone this skill to recognise the rates at which things are changing rather than their current state. And part of that "being one with the car" is the ability to "just know" what state the car is in (by mentally mapping a known steady state with all the changes you've felt). It is impossible (as far as we know) for anyone to be bang on accurate, but it's just not important anyway.

So.. as I was going to explain before, but ran out of time...

What this means is this..

Inexperienced driver (and in-fact, bloody good drivers also) tend to lose confidence in the car when it rolls freely. This does not mean people cannot accept it / deal with it and learn to make it work, but it's not easy.

The reason appears to be simply that you put in an input, and the car does not appear to react, except to fall over for a bit, and then scrabble round the bend. The truth is different to this, but the driver has to wait for that roll to settle before being able to sense the grip and surface, etc as well as he is able to.

Dispite the idea of a "perfect chassis set-up", the reality is that in almost all cases, performance and lap times come from the driver's confidence in the car.

[Digression - Ignore if you're short of time]

There was an interesting experiment a few years ago, when McLaren (I think) produced a truly neutral car, which was very carefully modelled for silverstone (again, I think) to be the most performant possible (Theoretical obviously).

Now, bear in mind that "truly neutral" does not mean what most people think of as neutral (ie. nice and easy to drive). Truly neutral means that the car is neither biased towards understeer or oversteer. This means that the car is on the limit ALL the time, and every input will either create oversteer or understeer.. it's all up to the driver. Road cars are ALL (and most race cars) biased towards understeer, unless something has gone very wrong.

Test drivers, current F1 drivers, touring car drivers, etc, etc all drove it and couldn't even keep it on the road, let alone make a fast lap out of it. A few managed to drive it but were very slow indeed. This car, should have been the fastest thing in the world, but the drivers had no confidence in the car, so couldn't make it go fast.

Interestingly, Senna drove it and was blisteringly fast. I have been told that Schuey has done the same, but I have never had that confirmed.

[Digression off! ]

So how do you generate driver confidence. In most cases, they want the driver to feel a reaction as quickly as possible after the input.

Mr Standard Road Damper Maker, says "what's the easiest way to do this? I know.. make it stiffer.. job done."

This means stiffer springs and stiffer damping. It also means harsh ride, reduced compliance.. but usually also a happy customer

This is obviously not the best way to make the car work though.

You would actually be far better off with much softer springs, but it makes the damper technology far more important, as you have to tread the narrow line of balance between too much initial damping (meaning reduced compliance) and too little initial damping (meaning slow response, and reduced driver confidence).

It's a clever and complex world out there, which is the main reason why it is such a passion of mine, plus the fact that there are no right or wrong answers.. well maybe a few wrong ones .

All the best

Simon

911

Wow! You are a craftsman with explanations too!
Most excellent.
Finding a 'complex' damper to get controll of the 'lighter' spring rate then should be the prime search?
Interesting point too on the wheel rate. John seems to be a knowledgeable type from my previous emails with him. The Scooby geometry in well understood, and I presume wheel weight and tyre compliance all play a (large?) part.

Does all this mean we need to get a quality damper, ie Bilstein, and ensure that it has bounce and rebound adjustable damping and fit stock rate springs? Can the classic 2 1/4 inch coil-over motorsport spring match the wheel rate of the stock scooby spring?

I am close to dumping my dreaded AVO's/coil over springs, and I'm thinking of Type C /Eibache (-25mm) springs. No adjustment, but progressive rate springs, matched damping and being off a heavier car, slightly stiffer for my hill climbing.
Add the the tons of Whiteline stuff already on the car, and I should be better off?

Although I am an engineer of 30 years, I am not a specialist in this subject, but it is very easy to get tied up in it all; facinating, and thanks for such a great insight to it all!
911