Help me choose between Tein Flex Z or HSD MonoPro ?

[MeisterR]

Depending on what you want and your budget, we have a few option available also.
For the higher performance fast road & track use coilovers, we also have the GT1.



The GT1 is a custom build suspension using advanced CNC internal completely engineered and manufactured in house at our UK workshop.
They have a lot of upgrade over the ZetaCRD such as our double CNC piston assembly, CNC shaft seals and glide rings, progressive rate bump stop, and our rally use moulded GT1 dust cover.




We build the GT1 to compete with top end Fast Road & Track single adjustable suspension such as the Ohlins DFV.
They are designed for easy adjustment, and provide great performance on and off the track.

Jerrick

[jamal]

The stock rates are 131/211 lb/in, or about 2.4k front and nearly 4k rear. I would not really expect doubling the front spring rate while leaving the rear stock to result in very good balance. Seems like you would wind up with a lot of understeer.

[MeisterR]

Originally Posted by jamal

The stock rates are 131/211 lb/in, or about 2.4k front and nearly 4k rear. I would not really expect doubling the front spring rate while leaving the rear stock to result in very good balance. Seems like you would wind up with a lot of understeer.

The OE setup is a rear bias setup.
Technically speaking, it does work; but the OE wanted to provide a different characteristic than what we want to provide.

On a rear biased setup, basically that rear don't want to grip as well.
Tail happy if you will, especially under power.

On our setup with higher springs rate front and lower spring rate rear.
Because that setup is paired to an adjustable damper, you can actually dial in your under / over steer using the damping adjustment.
That damping adjustment is the part that makes all the difference.

This way, we want the car to understeer because you can dial it out using the damping.
A softer rear setup is a lot more predictable, and that is a character you want in a fast road car because events often happen without warning when you are driving on a bumpy wet country road with blind corners.

Jerrick

[jamal]

Well, I get the dampers can change response in transitions, but consider a long sweeping corner; once the car is settled into the turn the dampers will have very little effect on balance.

I think I would prefer to start with the springs, swaybars, and alignment for balance instead of trying to compensate with the dampers.

[MeisterR]

Yes, and that is why we have the rear softer as that is the drive wheel.
You want to be able to apply throttle to balance the car on those long sweeper.
If that rear want to kick out under throttle, it makes those fast corner quite a bit more challenging.

Like I said, how the OEM setup the suspension is perfectly fine.
But the characteristic they were aiming to provide is different from what we want.

For a fast road & track setup, we prefer to be on the predictable and safe side.
If something sudden were to happen, a car that wants to understeer is much more manageable than one that wants to oversteer; because that rear want to find grip first.

Jerrick

[jamal]

Yeah I agree with that to a point. It is just that when you consider the motion ratio of the rear suspension, a 4k spring works out to a wheel rate of something like 2.3k, which is very soft compared to the front.

[MeisterR]

Originally Posted by jamal

Yeah I agree with that to a point. It is just that when you consider the motion ratio of the rear suspension, a 4k spring works out to a wheel rate of something like 2.3k, which is very soft compared to the front.

You don't want to look at the springs rate, you want to look at the wheel frequency.
That is what the wheel actually see, and it is the result from calculation that include the springs rate, the motion ratio, and the corner weight (That is the basic).

If you look at the wheel frequency compared to the front, it isn't miles out.
I can't remember the exact number, but I recall it is around the 1.6Hz which put the suspension to what OEM Porsche would offer on their car.

It isn't high because it isn't meant to be high, it isn't suppose to be back breaking.
The ZetaCRD are designed to be a setup that you can daily and enjoy.
We don't want a setup that you will get annoy at driving on for hours on the freeway because it is not comfortable.

You can use the damper to stiffen up the suspension for track use.
But like you said, the spring rate is the base and you want to make sure it is correct for the purposes.
If one is after a more track focused car, then we will have a different setup.

Jerrick