[Slumdog]

Good news ST still higher rate than stock which is too soft on the front right

 

[Alfissimo]

I think the track ones will be the biggest improvement. Prolly not great for daily driving but for track should improve.

Yes those are true race spec springs, but we are not sure yet if the shocks can handle them. Yes ST is too soft on fronts for sure.

 

[Alpha]

So...

I can do something more in depth at a later time, but the best way to put into perspective how the car will ride and handle is calculating the suspension natural frequency. It's literally the frequency the car will bounce at undamped. The calc combines the spring rate, corner weights, and suspension motion ratio (think how much leverage the spring has) and determines the natural frequency of the system.

Simply put, a comfy street car is around 1hz, a brutal track dedicated street car will be about 2hz. Street tires are designed around these parameters and key for making tires work. Cars using racing slicks might get up to 2.3hz, and high downforce race cars can be at 4+hz as you are more focused on managing aero loads than making tires work.

The rear frequency should be ~10% higher than the front to give a "flat ride". When a car hits a bump, the rear sees the bump fractionally later than the front. In order for it to catch up to the front and avoid a pogo feeling it needs to have a marginally faster frequency.

Best I can measure my 2.0T, it's around 1.25 hz. From limited info out there, 2.0 springs are around 180 lbs/in which would put the motion ratio around .7

Since motion ratio is mostly determined by the lower control arm, and the QV used the same arm, I'm going to keep that approximation. The stock spring rates also seem to indicate a similar motion ratio for the rear.

So fast forward from info given...

A stock QV would be a pretty sporty 1.5/1.6 hz front rear... Makes sense
ST would be a similar 1.63/1.7 hz
"GTA" springs a pretty masochistic 1.83/1.94 hz
Track springs definitely only for slicks at 2.3/2.4


I could be off by a +/- a tenth... Not exactly working with great info

Damping is another subject for another day

 

[Alfissimo]

Quickly as I am making dinner

The ST spring rates give ride frequencies of 1.48 Hz front and 1.33 Hz rear, which is low for a sports car. For example a Cayman R street car has ride frequencies of 1.5 front and 1.6 rear, while a Cayman GT4 street car has ride frequencies of 1.85 front and 2.2 Hz rear. A track car will typically have ride frequencies of 2.5 Hz and race cars even higher. So for a track car we need springs in the 700-800 lbs/in range. Then the next question is will the dampers have enough force to control the energy of these higher rate springs.


Attached is a first draft calculation of the spring rate, wheel rate, and ride frequency for the QV. I am estimating the motion ratios as 0.7:1 front and 0.6:1 rear, spring motion divided by wheel motion. This is an important ratio for the calculation, as it gets squared when converting spring rate to wheel rate, so am going to double check them to get a more accurate calculation. I need to measure the length of the lateral control arm and the distance from the spring/shock mounting point to the inner pivot. The inserted image shows the important dimensions.

In the rear suspension the spring and shock have different motion ratios, since they are not concentric and attach to the lower control arm in different locations. The spring motion ratio is the important one for this calculation and my estimate for the rear is that the spring is about 60% of the distance between the inner and outer lower control arm attachment points shown in the attached image.

We are not there yet, we think our springs might be too soft. I am having them make 2 more sets. 1 more slightly higher then a full race spring set up for a customer.

 

[Slumdog]

So interesting!!!! Way above my pay level but keep it up!!

 

[Alfissimo]

Alfissimo's "GTAm" springs Installed with caster/camber kit set at -2.5 Camber and GTAm CDCM software.

Exactly where we wanted the car to sit. Nearly 10mm lower than 17's springs with more rate than ST Springs or others. Testing next week at Sonoma Raceway. This raised the front by 4mm over ST and the rear is close the the same as ST, we still have a good rake on the car as it should.

More info coming after some testing. We should have them finalized by end of August and ready for production by Sept/Oct.

Made in Italy.

 

[JeFizz]

Alfissimo's "GTAm" springs Installed with the GMS caster/camber kit set at -2.5 Camber and GTAm CDCM software.

Absolutely exactly where we wanted the car to sit. Nearly 10mm lower than 17's springs with more rate than ST Springs or others. Testing next week at Laguna Seca. This raised the front by 4mm over ST and the rear is close the the same as ST, we still have a good rake on the car as it should.

More info coming after some testing. We should have them finalized by end of August and ready for production by Sept/Oct.

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Looks good!

 

[Alfissimo]

Looks good!

Grazie!

I think we got it the height correct. Raised front up properly.

 

[Alfissimo]

Decent testing today...

All modes are much tighter but still compliant enough to be very comfortable. A,N modes are not as floaty, way more sporty but comfortable as they should be in those modes. D is maintaining, you are able to feel the road a bit more but it's not too aggressive that it's uncomfortable. Race mode is fantastic. Over imperfections it maintains it's direction with minimal to no bump steer. I'd say it this point we pretty much nailed it. Could we up the rates, yes. The problem with this is that the shocks in the lower modes might lose their characteristic. These springs match the GTAm Suspension software perfectly and the Standard QV software.

Handling is superb. There is no more bounce, very little to no bump steer and overall the car feels extremely planted and ready for the track or a comfortable cruise.

Rates are roughly 15% higher than ST springs. Front end is at the proper height. All in all it's where we want it both in height and performance. I think the shocks can handle more spring rate as mentioned but I believe there will be a loss to the function of the other modes. The A, N mode will ride too firm as the shock will end up being too soft for the spring rates. This is most likely a keeper and once the track session is done on August 11th, we will most likely go into production sometime in Mid Sept.

Here are some more shots of the car and where front and rear sit heightwise.

 

[lizard]

Sounds very promising; from visual perspective I would like the front to be just a bit higher still, but it looks better than with ST Springs.

 

[Alfissimo]

Sounds very promising; from visual perspective I would like the front to be just a bit higher still, but it looks better than with ST Springs.

I understand. Stock 2017 springs are 26.1/2" (673.1mm/67.31cm) front. +/- depending on tire wear, front ground to fender measurement.

With our springs we are at 26 1/8" (663.57mm/66.35cm)

A drop from stock of 9.53mm All four corners. As mentioned, 10mm was the goal. I am ok with this. Ride quality is superb. Handling is much better. GMS kit of course helps with -2.5 camber. ST claims 20mm lowering front and rear. Others are around 30mm.

 

[Alfissimo]

I will put these into production in September.

I do not think we will adjust these any further. I feel the Height is perfect at -9.53mm lower than stock 17' height. The spring rates are right on.

I do not want to ruin the character of the car. I want Race-mode to be race-mode with a bit more steroids but I want to retain the purpose of the other modes which is sporty to comfort.

These springs are much more refined than the ST springs which again are too soft, too low in front and bouncy.

I have decided to powder coat them in RED. I know some of you wanted them black but I will offer powdercoating in black as an added option. I either have to do one color of the other, Red fits better for this application.

Pre-ordering will start Monday August 29

 

[The_Dude]

I will put these into production in September.

I do not think we will adjust these any further. I feel the Height is perfect at -9.53mm lower than stock 17' height. The spring rates are right on.

I do not want to ruin the character of the car. I want Race-mode to be race-mode with a bit more steroids but I want to retain the purpose of the other modes which is sporty to comfort.

These springs are much more refined than the ST springs which again are too soft, too low in front and bouncy.

I have decided to powder coat them in RED. I know some of you wanted them black but I will offer powdercoating in black as an added option. I either have to do one color of the other, Red fits better for this application.

Pre-ordering will start Monday August 29

How do these compare to the KW springs?

 

[JeFizz]

How do these compare to the KW springs?

KW are the ST springs @Alfissimo refers to.

 

[The_Dude]

KW are the ST springs @Alfissimo refers to.

I thought they're custom springs so if they are Law's how much different are they compared to the standard KW?

 

[Alfissimo]

I thought they're custom springs so if they are Law's how much different are they compared to the standard KW?

As noted above, they are about 15% more rate than ST which are by far too soft. They raise the front properly so car sits correctly. Handling is much more composed, no bounce, no teeter. Overall a great setup. TUV certification will come with the springs.

They will out perform the ST springs (KW) by a long shot.

 

[The_Dude]

As noted above, they are about 15% more rate than ST which are by far too soft. They raise the front properly so car sits correctly. Handling is much more composed, no bounce, no teeter. Overall a great setup. TUV certification will come with the springs.

They will out perform the ST springs (KW) by a long shot.

I thought the KW springs are different than the ST springs. I have the KW on my car and they're not bad but I wish that the front was higher by .5 inches.

 

[Alfissimo]

I thought the KW springs are different than the ST springs. I have the KW on my car and they're not bad but I wish that the front was higher by .5 inches.

No. ST (suspension Techniques) is apart of KW. You have the ST Springs. KW does not brand these types of Suspension springs, KW is their coilover department.

Search results for: '28215042' | ST suspensions

www.stsuspensions.com

In 2005, the German suspension manufacturer KW automotive GmbH, well known internationally for their KW Coilover height adjustable suspension systems, purchased both Belltech Sport Trucks and Suspension Techniques and launched KW automotive North America Inc. With the name purchase and a formal name change of the brand to it’s current nameplate of “ST suspensions”. The infusion of the technology from ST’s new parent company took ST's game to a whole new level, increasing not only its application range coverage, but adding the innovative ST Coilover program, which was modeled after a galvanized KW Variant 1 coilover design.

 

[Alfissimo]

Springs have been tested at Sonoma Raceway. Quick comment from driver "Hey so the car was amazing. So good. "

 

[Kyle]

So just to confirm, these springs can be installed and ready to go without the need for the software?
What is the price of the springs?
Also, do you ship to Australia?