Ride hight 2

[Petrus]

Same subject, different angle.

Quite a lot of Mk.3 owners, here, UK, US, drop the car using after market lowering springs.
This lowers the center of mass and because the spings are markedly stiffer, decreases roll/suspension movement.

It álso alters; negatively affects, the geometry of the car. Thus affects the performance negatively.
I read hardly anything about the latter and just a handful have fitted the roll center correcting ball joints.

Same thing weight shaving. Quite a few owners lóve lightening their car.
This too álso alters; negatively affects, the geometry of the car. Thus affects the performance negatively.
I don´t know how bad the effect of lowering is but the slightly higher ride is rather scary near the sharp end of pushing things: The car properly twists it´s knickers in a knot when cornering HÁRD on real world undulating roads. Now I am used to rally classics so are not easily upset by twisted nicker but this is a modern mid engined car.
I have, sofar, read nothing about the latter.

Spirit does not go into it either in the video clips. It is obvious that he has lowered the car and he lets on to usu heavier spring setting rear but he does not mention how he sorts the geometry.
I have the suspicion that thís is why his car goes so well, so much better than most MR-S.

Thus we get to my question:
What dó you guys do to address the lightness of the car? Do you go lowering springs and ball joints or? Please share!

[Petrus]

Would any of you happen to have access to a copy of Miliken & Miliken?
On page 683 there is an equasion which, including explanation, I would really love to stress my brain matter on.

As to multi adjustable suspensions, I hava had many of such suspensions on my racing and enduro bikes and it took like forever to arrive at settings for different circumstances. It was/is no doubt a lot better but I positively háted it.
On this car I would need to know/understand what the ride height setting doés first before I´d go that way.
Been searching the varous MX5 fora too as I am ofcourse not adressing a new issue and there are several times more MX5 owners struggling with this than MR2 owners.
As to adjustment for load with a passenger I would not bother as I simply will not nearly push the car as close to it´s limits with that added responsibility. Not to mention that the girls are sure to whack me hárd on the head the moment they have a hand free...

It basically is a search for understanding.

[james_ly]

I don't have any real science to back this up, just driving impressions on track. Fitting lower and stiffer springs/dampers I found it gave me more front end grip because the front tyres weren't rolling on the sidewall as much. Also sharpened the steering and just generally gave a bit more confidence. Didn't notice any increase bump steer, tramlining etc

[Petrus]

Thank you for the feedback James.

[Dev]

Same subject, different angle.

Quite a lot of Mk.3 owners, here, UK, US, drop the car using after market lowering springs.
This lowers the center of mass and because the spings are markedly stiffer, decreases roll/suspension movement.

It álso alters; negatively affects, the geometry of the car. Thus affects the performance negatively.
I read hardly anything about the latter and just a handful have fitted the roll center correcting ball joints.

Same thing weight shaving. Quite a few owners lóve lightening their car.
This too álso alters; negatively affects, the geometry of the car.

Two points from my many years of experience with this car.

  Most of the lowering spring options have been optimized to work with the stock struts.  They are generally stiffer  but that is to account for the reduction in travel however they are generally soft.  This option will lower the car conservatively on a budget  but not to the point where it will effect the roll center enough to degrade handling. These lowering springs are generally for looks more than actual performance.
Because the lower center of gravity you may  have a little better handling but nothing as significant as you get from a proper coilover set up.
   
There are many Coilover options out there but very few that have been tested for this car as a finished product. Some like the KW are tested on a shaker rig which is the right way to design a proper coil over system.
Many of the other cheaper options will give you a overly stiff and harsh ride which is not optimal but unfortunately most equate stiffness with better handling which is not always the case.  The dampeners valving  must be properly matched with the spring rates. 

Even with all these options you do not need the fancy ball joints to correct for the roll center unless you drop the car by more than 
Two inches which  is too low to get wheels and certain tires to fit not to mention that the slam look is for show or for drifters. Generally you don't need revised ball joints to lower this car unless you slam it for a special purpose. 

In regards to weight loss  it can effect the spring rates but not enough to matter unless the entire car is stripped. There is quiet a bit of forgiveness in this area.

If you want to do it right get a proper twin tube  coilover system like the KW variant 3 and enjoy. Cutting springs or lowering springs is really not going to do much of anything except for looks.

[Dougster7]

I have to say I think you are over thinking the whole suspension thing on our cars. There are many options for our cars on handling and ride height and cutting springs is certainly not one if ever choose. As Dev states unless you REALLY slam it so you can't even clear a painted white line on the road you'll be fine with standard springs or progressing onto coilovers. The club boasts many cars from standard to turbo and supercharged both 1zz and 2zz....and larger engines and their cars stance / handling will be suited to their preference / requirement. What I'm trying to say is the standard suspension is pretty decent for a small road going sporty 2 seater as it is, of course there is room for improvement depending on budget and preference. Usually starting with Tein springs then onto coilover set ups. I have coilovers and some bracing and both track and fast road the car with a 2zz and I love it, never had a car that handles as good as it does and with so much feeling to the steering. Don't lose sleep on this and stick to available brand names and you'll be fine unless you 1000bhp it....then you might need some custom advice


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[Petrus]

Thanks for sharing the information and the relativating.

Yes, I am overthinking. The reason is past experience with ´performance products´. Only a minority is actually a functional improvement and even then not always a better overall compromise.
To be able to make the choice which suits mé, I try get the most info.
I álso realise that this delightful car is a cheap runabout with constructional limits set by the mass production / parts comonality with cheap consumer cars.
The thing is, it is súch a joy to thrash over mountain roads that it is easy to get carried away and want móre instead of driving within/around the conceptual limits.

Indeed one of the most important things is that the damping and spring are matched.

As to the roll center hight I may be overly critical BUT ... the effect of shifting it is most definitely undesirable when pushing the car.

To complicate matters further still, am looking at the rear stabeliser bar too 

[Dougster7]

I changed out the front and rear sway / arb bars for whiteline ones along with front and mid bracing. Along with the suspension (Meister) it's awesome fun. No matter what you change out it's about getting a feel for it, that goes for suspension, tyres, engine or bracing etc. You could technically have the best set up ever for certain conditions but might not suit your driving style, or local roads. If you're mainly commuting on roads go Tein springs for a lower look and bit better handling, if you drive it hard on twisty roads or track go coilovers, just bear in mind the top mounts need changed at an average of 80k miles and that coilovers usually come with them, they're not cheap buying on their own! With either of the above you'll notice a nice difference from stock as long as you have good tyres to match....now that's a topic you'll lose sleep on [emoji23]


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[Dev]

Thanks for sharing the information and the relativating.

Yes, I am overthinking. The reason is past experience with ´performance products´. Only a minority is actually a functional improvement and even then not always a better overall compromise.
To be able to make the choice which suits mé, I try get the most info.
I álso realise that this delightful car is a cheap runabout with constructional limits set by the mass production / parts comonality with cheap consumer cars.
The thing is, it is súch a joy to thrash over mountain roads that it is easy to get carried away and want móre instead of driving within/around the conceptual limits.

Indeed one of the most important things is that the damping and spring are matched.

As to the roll center hight I may be overly critical BUT ... the effect of shifting it is most definitely undesirable when pushing the car.

To complicate matters further still, am looking at the rear stabeliser bar too 

I have a deep suspicion with circumstantial evidence that the roll center height is far more optimized for this car when it is lowered but only to a certain point and then it is degraded.

The TRD Sportivo suspension kit that was made for this car included struts, sway bars and one other interesting item which was two dog bones that lower the subframe. It was initially thought it would bring the roll center back in alignment. 
After much discussion was found that that the dog bones go in the opposite direction of making the roll center worse as if you were to lower the car further. 
 
The TRD kit was just a mild lowering so it is quiet possible that the optimum roll center is lower than the engineers designed for and the car was made at a time when Toyota started making provisions for cars to be modified by future enthusiasts for their TRD line.  Basically Toyota knew that their cars might be modified by enthusiasts and made some minor allowances. 

[Petrus]

I have a deep suspicion with circumstantial evidence that the roll center height is far more optimized for this car when it is lowered but only to a certain point and then it is degraded.

The TRD Sportivo suspension kit that was made for this car included struts, sway bars and one other interesting item which was two dog bones that lower the subframe. It was initially thought it would bring the roll center back in alignment. 
After much discussion was found that that the dog bones go in the opposite direction of making the roll center worse as if you were to lower the car further. 
 
The TRD kit was just a mild lowering so it is quiet possible that the optimum roll center is lower than the engineers designed for and the car was made at a time when Toyota started making provisions for cars to be modified by future enthusiasts for their TRD line.  Basically Toyota knew that their cars might be modified by enthusiasts and made some minor allowances.

Véry interesting food for thought.

TRD only slightly lowering the car seems to me a matter of retaining both ground clearance and, possibly more importantly, wheel travel.

Lowering the subframe is an intriguing modification. I was not aware of this. It is quite a fundamental mod affecting the geometry of the rear suspension, lowering the mounting point of the lower suspension strut. Indeed doing the same as shortening the springs.
Intriguing and apparenly not making any sense.
Now if, big IF, the roll centre hight is ideally a bit lower than standard spec. it does explain why I so notice the car jacking with it a bit higher.

[Petrus]

as long as you have good tyres to match....now that's a topic you'll lose sleep on [emoji23]

Got Enkei RPF1s with AD08R which are totally at home here in the south 

The awesome traction of those are part of the problem: Without this level of grip I would not háve the problem.

[Petrus]

The TRD Sportivo kit:

2*Front shock absorber 823/559N
2*Rear shock absorber 1254/490N
2*Rear Suspension Upper Support Extra firm type
2*Front Coil Spring K=15.6N/mm (Ride height approx. 20mm lowering)
2*Rear Coil Spring K=33.6N/mm (Ride height approx. 20mm lowering)
2*Rear Suspension Member Spacer t=3.2 Material: Steel Changein roll-centre position
1*Front Stabilizer Bar (φ23 Solid type)
2*Front stabilizer bush Exclusive for above stabilizre bar Extra firm type
1*Rear Stabilizer Bar (φ17 Solid type)
2*Rear stabilizer bush Exclusive for above stabilizre bar Extra firm type
4*Front stabilizer cushion Extra firm type

The ´dog bones´ are 3.2 mm thick spacers.

[Petrus]

A baffling lack of concrete; factual ´geometry´, info on the suspension upgrades availeble. The absense of specifications of lowering springs is symptomatic (Tein being the exception).

Neither is there much (understatement) on the TRD Sportivo spacers for the subframe.
Been measuring a bit under the car and the effect is a definite lowering of the roll center. Working form 20 mm lowered springs (as per TRD kit) the effect is in the order of 30 mm!!!

See a schematic and now imagine lowering the chassis side of the bottom strut





Note:  I have chosen thís illustration as it visualises the effect BUT it is also an example of the negative effect of lowering a car too much: The distance between COM and RC has increased so this car will roll MÓRE despite lowering.
As such illustrating twó things 
See; ´overthinking´ is not all bad 

[Dougster7]

I'll take your word for it buddy [emoji1303]

I'm not that technically minded, all I know is I slapped on the Meisters, Ad08's, front and rear ARB's, front upper and lower bracing and I can really throw it around corners on both track & road. The steering feedback is very good, as I said best I've ever had from a car.

By all means maybe there's room for improvement but I think I'd need to be born again with the 100% race driver mentality before I noticed.

Hope you get what you're looking for from your 2 [emoji469]


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[Petrus]

Still wondering about the Sportivo ´dog bones´,






but apart from that decided to order Tein springs and rear ARB.
I strongly suspect that the rear arb will be a major factor but I nééd to get the car back down.

[Petrus]

btw. am at the moment at the coast with the 340. Need luggage space.
Driving the crap out of the thing on B-roads and highways. It is set up  5 cm. higher on the springs. It moves all over the place BUT... the Panhard rear axle is very well desegned and does not allow the rear to wallow. At the limits of adhesion/ car design the car has NO bump steer at the rear.
Ok, the speeds are higher, forget about that, but the rear of my MR inspires léss confidence in that limit area. Thát is what I want restore. Not so much higher corneing speeds but more linear response. The rear is now nót sufficiently ´planted´. When it is ´jacked´, it wallows.
The front moves even more than the rear but it is all linear; it does not wallow; is predictable; confidence inspiring. Thát is the most important aspect.
I am having more fun with the bouncy 340 than with the MR; that múst be adressed.

[Dev]

btw. am at the moment at the coast with the 340. Need luggage space.
Driving the crap out of the thing on B-roads and highways. It is set up  5 cm. higher on the springs. It moves all over the place BUT... the Panhard rear axle is very well desegned and does not allow the rear to wallow. At the limits of adhesion/ car design the car has NO bump steer at the rear.
Ok, the speeds are higher, forget about that, but the rear of my MR inspires léss confidence in that limit area. Thát is what I want restore. Not so much higher corneing speeds but more linear response. The rear is now nót sufficiently ´planted´. When it is ´jacked´, it wallows.
The front moves even more than the rear but it is all linear; it does not wallow; is predictable; confidence inspiring. Thát is the most important aspect.
I am having more fun with the bouncy 340 than with the MR; that múst be adressed.

You might be describing what is known as mid corner float.  In my experience with driving many MR-S cars and following many of the new cars as they age including  many of the discussions it is a known issue that the stock struts for this car are expended at around 40k miles for any kind of serious performance driving, and it doesn't inspire confidence.

It doesn't mean the struts are bad for normal daily driving but when it comes time to punish the car it is poorly dampened very early in its life cycle unlike other cars where the struts can last twice as long for this purpose.

After changing  out the struts to many of the aftermarket options including similar KYB replacements  this issue becomes non existent. 

Another issue that makes the car less confidence inspiring is too much air in the tires.  I was asked by an owner to evaluate his terrible handling MR-S and I felt the car was down right dangerous because it lost all of its feel.  It  had me perplexed and as the owner was talking to me he casually mentioned that he inflates his car to 40psi for all four tires! 

There was a lot of back and forth trying to explain to him why this was a bad thing and he was in strong disagreement until I persuaded him to lower the air pressure and once that happened it fixed the handling issue completly.

This car can be very sensitive to changes especially radical changes with the rear sway bar. This is why a four position Whiteline rear sway bar is invaluable to setting up the behavior at the limit. 

[Petrus]

Good to know about the shocks.

I have the specced tyre pressure with just a whiff more up front.

Had ordered a WhiteLine 

[Dougster7]

You'll love the whiteline arbs, we'll worthwhile [emoji1303]


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[Petrus]

You'll love the whiteline arbs, we'll worthwhile [emoji1303]

Íf you can get one it seems 

[Ardent]

What a great read.

Heard of the sportivo but not the contents of the kit.

[Petrus]

Some more concrete data:

The Cusco 18 mm arb has 180% of OEM stiffness at the soft (outer) hole, 260% in the hard (inside) hole. This is the bar Orido uses in the Spirit MR-S. Front standard.

The Whiteline 18 mm has foúr position; from soft to hard (out to in), quite surprising; 65%, 100%, 130% and 160%.

Now, assuming the TRD one being in the same position as the standard one, than it would be 113% stiffer.

If this shows anything first and foremostly, then it must be that one must try FIND THE SPECIFICATIONS! of any mod.

The lowering springs too are surprising in the very same way.

TRD
Front Coil Spring K=15.6N/mm (Ride height approx. 20mm lowering)
Rear Coil Spring K=33.6N/mm

Tein
Front 1.9Kgf/mm (30 mm. lowering)
Rear 2.9Kgf/mm

Notice the surprising element? It is not the stiffness but the fron/rear difference; 100% in the TRD kit, 50% in the Tein springs.
Oh, the second surprise is that TRD goes stiffer at the rear than Tein while lowering less!

I do not know what the standard springs are.

Mr.Orido suggests wayWAY harder spring setiings; road: 5, 6, 7 kg. front, 10 rear.

I want to add Orido´s summary of the front/rear setting; ´front soft ok; standard stabeliser ok; rear hard rate, hard stabeliser; easier to control.´
In numbers:
5 kilo front, standard arb
10 kilo rear, Cusco stabeliser
Basically... we are sissies 

p.s. a stiffer arb will also have a stiffening side effect on the springing.

[Joesson]

I can't offer anything to the discussion other than it is best when making comparisons to compare like with like.
The units used differ by a factor of around 10 as shown below that I believe may be helpful.


TRD
Front Coil Spring K=15.6N/mm (Ride height approx. 20mm lowering)
Rear Coil Spring K=33.6N/mm

Tein
Front 1.9Kgf/mm (30 mm. lowering)= 18.63N/mm
Rear 2.9Kgf/mm.                            = 28.44N/mm

[Petrus]

Thank you Joesson; I assumed that all would be aware of the factor 9.8   

[Dev]

You can't base much on the Orido car without taking much into context the whole package including the purpose. 

The TRD kit has sway bars that are designed around the damper and springs they provide. 

The purpose of the adjustability of the sway bars is to give you flexibility in making gross adjustments since changing spring rates is not always possible and the swaybars also allow the car to be a bit more forgiving comfort wise instead of using much higher spring rates. 

For a street driven car you don't want very high spring rates otherwise you will end up with a bouncing brick. You want both the damping and spring rates to match the level of grip of the tires.  Overly stiff suspension is counterintuitive to grip but needed once you run tires exceed the level of grip the suspension can provide.

This is why a good researched suspension system is also comfortable.
This is also why many options for this car are not optimal but the owner will not know the difference because he will equate stiffness with better handling.