MeisterR coilovers for FR-S / BRZ, what do you use your suspension for?

[churchx]

Originally Posted by MeisterR

..
The good news is that it will lower the car at least 1.5", and the better news is that the car will still ride nice and perform well.
..
In the end, we took the 5/4 as the setting and designed a longer damper.
We decided that if people want to go REALLY low, there are plenty of choices on the market.
..

Depends to whom. There might be ones like me too, that don't want any lowering below stock or even sometimes slight lift. Market is full of aftermarket stuff targeting lowering crowd, yet options for opposite are relatively very scarce, unless very expensive custom or in lower end with other deficiencies making them less competitive products vs better overall quality lowered ones.

[Captain Snooze]

Originally Posted by MeisterR

So that is the quick explanation of "why" we have the rear end softer on the FR-S / BRZ.
Also, 5/5 will not work, it will hit harmonic.

Where do motion ratios fit in to all of this?

[MeisterR]

Originally Posted by churchx

Depends to whom. There might be ones like me too, that don't want any lowering below stock or even sometimes slight lift. Market is full of aftermarket stuff targeting lowering crowd, yet options for opposite are relatively very scarce, unless very expensive custom or in lower end with other deficiencies making them less competitive products vs better overall quality lowered ones.

The FR-S got a lot of adjustments available, so the front isn't a problem no matter how high you want it.

The rear on the other hand have a limited range of adjustments.
The current coilovers should be able to get within a reasonable range.
But if you are after taller than stock height, we can probably do something.

Jerrick

[MeisterR]

Originally Posted by Captain Snooze

Where do motion ratios fit in to all of this?

Motion ratio is the calculation how the springs rate reach the wheel.
You use it to give you an idea of what the "wheel" actually see.

There are other parts, but I'll throw up some simple number.
Some cars have low motion ratio, so the front of a Toyota Supra I think run about a 0.6 to 1.
So that mean if you put a 10kg/mm springs on, the wheel only see 6kg/mm

Some car have high motion ratio, the rear of a new Miata have a 0.9 motion ratio.
So that mean if you put a 10kg/mm springs on it, the wheel actually see 9kg/mm

What that mean is you can put 12kg/mm on a Supra and a 10kg/mm springs on a Miata; and the Supra is actually using the "softer" springs even though the springs is harder than the Miata.

Suspension motion ratio difference is one reason why you cannot use springs rate from different platform to compare.
Just because X car is using 10/8 and it is good, it doesn't mean Y car that is similar in size and weight can use 10/8 and achieve the same effect.

Jerrick

[Captain Snooze]

Originally Posted by MeisterR

Motion ratio is the calculation how the springs rate reach the wheel.
You use it to give you an idea of what the "wheel" actually see.

There are other parts, but I'll throw up some simple number.
Some cars have low motion ratio, so the front of a Toyota Supra I think run about a 0.6 to 1.
So that mean if you put a 10kg/mm springs on, the wheel only see 6kg/mm

Some car have high motion ratio, the rear of a new Miata have a 0.9 motion ratio.
So that mean if you put a 10kg/mm springs on it, the wheel actually see 9kg/mm

What that mean is you can put 12kg/mm on a Supra and a 10kg/mm springs on a Miata; and the Supra is actually using the "softer" springs even though the springs is harder than the Miata.

Suspension motion ratio difference is one reason why you cannot use springs rate from different platform to compare.
Just because X car is using 10/8 and it is good, it doesn't mean Y car that is similar in size and weight can use 10/8 and achieve the same effect.

Jerrick

Sorry, I worded my question poorly.
I meant how is it that 5/5 hits harmonic given the difference in effective spring rates.

[MeisterR]

Originally Posted by Captain Snooze

Sorry, I worded my question poorly.
I meant how is it that 5/5 hits harmonic given the difference in effective spring rates.

It is the wheel frequency that you are looking at, which is a function of the springs rate, motion ratio, corner weight, etc.

If the wheel frequency are too close to each other, that is when it is possible for you to hit harmonic.
When we work the number out, 5/5 end up with a very close wheel frequency between front and rear.

Jerrick

[MeisterR]

Just to bring this back up again.
We got more cars on the road with out suspension now, just want to see any other members want to chime in on what they are looking for from uprated suspension for the FR-S / BRZ

Jerrick

[Tor]

Originally Posted by MeisterR

It is the wheel frequency that you are looking at, which is a function of the springs rate, motion ratio, corner weight, etc.

If the wheel frequency are too close to each other, that is when it is possible for you to hit harmonic.
When we work the number out, 5/5 end up with a very close wheel frequency between front and rear.

Jerrick

Hi Jerrick,
I have a question regarding wheel frequencies and the the choice of harder spring front vs rear, or rather higher frequency front vs. rear.

A suspension tuning company called Fat Cat Motorsports uploads a ton of educational videos to youtube. One thing he advocates passionately is the concept "flat ride", in which the well frequency should be higher in the rear, to allow the rear to catch up with the front when going over a bump.

Assuming:
Front (per side):
Sprung weight: 660 lbs (+80 lbs unsprung)
Motion ratio: 0.95
Spring: 5 kg/mm
Wheel Frequency = 1.94 hz

Rear (per side):
Sprung weight: 495 lbs (+80 lbs unsprung)
Motion ratio: 0.75
Spring: 4 kg/mm
Wheel Frequency = 1.58 hz

(using http://www.racingaspirations.com/app...ncy-calculator).

Other rates and frequencies:

4/5: 1.73/1.77 hz
5/4: 1.94/1.58 hz
5/5: 1.94/1.77 hz
5/6: 1.94/1.94 hz
6/5: 2.12/1.77 hz
6/6: 2.12/1.94 hz
6/7: 2.12/2.09 hz

Stock 2.3/3.3: 1.32/1.44 (Flat ride)

He argues that "flat ride" is essential for comfort. And you can run less damping because the springs will naturally settle. Explained here (direct link to time), from 05:15 to approx 07:00 if the link doesn't jump there.
[ame="https://www.youtube.com/watch?v=LxMPhR_6ilg#t=314"]How Shocks Work - Street Class Tuning - Damping and Flat Ride, v2.13 - YouTube[/ame]

Now to my questions:
1) Even if my numbers above are slightly off, there is still a clear tendency that all aftermarket suspension setups have a higher wheel frequency in the front (as opposed to stock which indeed follow the flat ride concept).

To get flat ride and and a harder suspension, it seems the rates should be something like this, 4/6: 1.73/1.94 hz or 5/7: 1.94/2.09 hz?

What speaks against such a setup?

2) How do anti-swaybars come in to the equation? Are they altering wheel frequencies?

Thanks.

[MeisterR]

With vehicle dynamics, everyone have a different way of doing things.
For us, the sample way to look at it is to keep fast road car wheel frequency under 2.0Hz, as at that point the ride quality get to a point where it will be too harsh.
You can only run damper so soft until it will not control the springs anymore, and that is where 2.0Hz normally are.

Then there is suspension harmonics to worry about.
If the wheels frequency cycle are too close to each other, at a certain weight the vehicle front and rear suspension can reach a harmonic where they start working with each other during an oscillation cycle.
This is when you get the floaty feeling and it is a pretty horrible thing and should be avoid at all cost.
(I think that is where he is saying what the flat ride avoid).

Finally, the lower wheel frequency rate should be placed in the drive wheel.
This allow the drive wheel to get more "traction" than the other wheel, and therefore provide better balance under power.
So RWD will have the lower frequency in the rear, this will help it get traction under power out of corner.
FWD will have the lower frequency in the front, this will help it turn in as the rear will be more lively.

Now you CAN have the higher frequency in the rear, but it will make the rear lively and may not feel as "sure footed".
It also mean at the limit, you can get the tendency of the rear kicking out under power which isn't very good for a fast road car with uneven road surface and all.

Anti-roll bar is part of the vehicle dynamic calculation, so we will need to plug it in to see how it affect the effective wheel frequency as it is basically a spring put on side way.

This might be off topics a bit, so if you got any other questions drop me a PM.
I am always happy to talk you through it.

Jerrick

[Tor]

Originally Posted by MeisterR

This might be off topics a bit, so if you got any other questions drop me a PM.
I am always happy to talk you through it.

Thanks for the explanation. He is actually a Miata guy and also mentioned a Porsche he set up with higher frequency in the rear. Also the stock GT86 suspension has the higher frequency in the rear.

I brought it up here, not specifically in relationship to your coilovers (as it seems almost all aftermarket coilover have the lower frequency in the rear, even if the rear has the higher spring rate), but because there was a discussion here about frequencies etc.

I can put up a post in the suspension Q&A thread, so more can chime in.

[solidONE]

Originally Posted by MeisterR

Hello everyone,

Coming from the UK, I am just trying to get a general feel what community want from their suspension.
MeisterR suspension are design as multi-role suspension that does everything well.

For the FR-S / BRZ, we have the ZetaCRD+ Coilovers.
Springs rate specification are Front 5kg/mm, Rear 4kg/mm.

Our ZetaCRD are design for fast road & track use, and so the springs rate are design around compliancy over uneven road surfaces, while retaining damper adjustments for track use.

However, most enthusiast seems to engage with SCCA Auto Solo that require a slightly different setup than most track suspension.
We want to know do track enthusiast want dedicated setup that that is even stiffer to handle quick transition such as Auto Solo event, but give up compliancy for road use in return.

Let us know what you think, we are just taking in opinion at the moment.
Looking forward to hear from everyone.

Jerrick

I think your approach covers a large portion of the market. For myself, I'd sacrifice a little bit of compliance for better performance on track, but not so much where the ride under cruising speeds is jarring or too much unwanted oscillation. "Firm yet compliant" for cruising at the softest settings but formidable at a fast pace on a circuit at the firmer side using high performance street tires or even semi-slick tires. Is that asking for too much from a single adjustable damper? Or, do you think you've already achieved this result with your current product?

[renfield90]

Originally Posted by Tor

Thanks for the explanation. He is actually a Miata guy and also mentioned a Porsche he set up with higher frequency in the rear. Also the stock GT86 suspension has the higher frequency in the rear.

I brought it up here, not specifically in relationship to your coilovers (as it seems almost all aftermarket coilover have the lower frequency in the rear, even if the rear has the higher spring rate), but because there was a discussion here about frequencies etc.

I can put up a post in the suspension Q&A thread, so more can chime in.

Roughly speaking, there are two schools of thought regarding frequency:

1. The rear should have the higher frequency, because it is traveling behind the front wheels; when you travel over a bump, you want the rear to settle faster than the front so that the car can be ready for another input sooner (turning the wheel, applying power mid-corner, etc.). In general you want both ends of the car to settle at the same time.

2. The rear should have the lower frequency, so that bumps to the drive wheels induce slower motion and thus make the car easier to drive.

I find the latter is common among high horsepower car owners (think Corvette Z06, Mustang GT, etc). There may be some truth to the easy to drive bit, especially depending on tire selection. The tire has its own "spring" rate of sorts and therefore its own natural frequency, and it needs to play well with the suspension frequency you select.

My personal opinion is that it really doesn't matter too much that the rear is faster as long as the suspension is properly damped. Sure, the high HP car might be easier to drive, but that does not mean it is the fastest setup (it might be the fastest setup for a given driver's talent level, but let's stop here before I begin impugning wholesale the talent of Corvette owners).

Note that ultimately, the goal is to keep the tire in its happy place. None of what I said matters if you pick a frequency or car balance that makes the tire unhappy. This stuff isn't easy and that's why race engineers make some decent money into the six figure range.

[ajc209]

All this talk of wheel frequencies affecting the balance. Roll stiffness is what we should be talking about as that includes the spring and roll bar stiffness.

[MeisterR]

Originally Posted by solidONE

I think your approach covers a large portion of the market. For myself, I'd sacrifice a little bit of compliance for better performance on track, but not so much where the ride under cruising speeds is jarring or too much unwanted oscillation. "Firm yet compliant" for cruising at the softest settings but formidable at a fast pace on a circuit at the firmer side using high performance street tires or even semi-slick tires. Is that asking for too much from a single adjustable damper? Or, do you think you've already achieved this result with your current product?

That is what we have done with the ZetaCRD within reason.
Springs rate isn't out of this world.
Softer damper setting will have low cracking pressure as well as reasonable damping force leading to a compliant ride especially over uneven road surfaces
Stiffer damper setting will have increase cracking pressure as well as higher damping force leading to better steering and damping response.

That is one of the reason why adjustable compression and rebound combined damper is essential for providing a good fast road & track suspension.

Originally Posted by ajc209

All this talk of wheel frequencies affecting the balance. Roll stiffness is what we should be talking about as that includes the spring and roll bar stiffness.

To be honest, springs rate is but one of the item in calculating vehicle dynamics.
Roll centre, corner weight, anti roll bar, tyre compound, etc all play a role.

The springs wheel frequency is a good base because you know if you are using a road car, you want to keep those wheel frequency under 2.0Hz
And it is a level playing ground for any car, rather it is a FR-S or a Porsche, the car may change but the numbers stay the same.
Where if you have a race car then you can go over it.

For most clubman driver, we find around the 2.5Hz is where they end up having a happy medium between body roll control and predictability.
For professional race car, we have gone into mid 3Hz, and sometime even info the low 4Hz depending on what we are doing.

Jerrick