Actual Spring difference BRZ vs FRS

[bpracer]

Originally Posted by icemang17

....
My intial impressions on track with my bone stock FRS was interesting....while its extremely "lively" on turn in with great feel, the tires SUCK and the suspension does need improvement.....its a great street-track tradeoff but for serious track work it needs to be much stiffer with more roll control, more rebound control and lower ride height....

While the spring rate is interesting that is only half the roll rate discussion. Do both models have the same size sway bars? The FR-S bars are 18mm/14mm front/rear. Is the BRZ the same?

If the BRZ has a bigger front bar, the front roll rate could be closer to the FRS.

My entire one day driving impression of my, new FR-S is that it is too stiff in the back. The rear stepped out much easier than I was expecting and caused me to immediately check that the rear tires were properly inflated (they were). Of course, as mentioned earlier, the tires suck.

[xwd]

Everything else about the suspension is identical other than the spring rates.

[bpracer]

Originally Posted by Esoteric

Once more companies release front sway bars watch how many people go after them like crack.
It will be the same thing that happened in the Impreza/STI world- dollar for dollar it may be a highly enjoyed upgrade, but its only one way to skin a cat.

Comparing the spring rate difference front to rear, it looks like Eibach is matching the BRZ %-wise exactly. Unless you change springs, it looks like a bigger front bar will help.

I find it pretty daring that the FR-S has this set-up from the factory. That, or the alignment on my car from the factory is bad and has some rear toe-out.

[Soravia]

Originally Posted by Jackson

Pro-Kit (82105.140)
Front: lowers 1" | rate 148-200lbs/in
Rear: lowers 1" | rate 103-274lbs/in

Sportline (4.10582)
Front: lowers 1.4" | rate 120-211lbs/in
Rear: lowers 1.4" | rate 86-296lbs/in

Both kits are progressive in design but that initial rate doesn't mean much. Even at static height the spring will already be into the upper end of the progessive rate.

We do all of our own testing in Corona, CA. We did test the BRZ and FR-S shocks and they are both very similar. There wasn't enough difference to convince that they changed valving from the FR-S to BRZ. Our engineers think the shocks are most likely the same but just tested slightly different from one another. Most OE shocks will have a slight variance in shock dyno numbers from car to car.

With such drops on ride height (and reduction in suspension travel) and the marginal increase in spring rates, the car will be hitting the bump stops much harder on just about any road bumps.
Roads like we have in Texas are very horrible and limited and soft suspension will send the car losing grip all over the place, not to mention harsh ride due to strong impact with the bump stops.
Is Eibach going to come out with a properly tuned set (shocks, REAL stiff springs, matched bump stops)?
I just had Auto-X with Fat Cat Motorsports suspension equipped turbo Miata along with other Miatas running different setups. 800lb/500lb (OEM is around 190lb/120lb) FCM setup drove better (very neutral under hard cornering, hard braking, mid-corner braking and gas, small body roll, almost no bounce), posted better times and rode better over the bumps. (FCM setup can be used with choice selection of springs similar to Eibach Motorsports springs match with custom valved shocks)
I know Eibach actually sells 2.5" ID springs for such applications. I hope there's more focus on those than the horrible "Lowering Springs" that reduce ride quality without substantial performance gain.

Horrible Eibach for people who don't understand suspension working.
http://performance-suspension.eibach...rmance_springs

Real Performance Eibach for professional people who know what they're doing.
http://performance-suspension.eibach..._spring_system

I just hope there's a complete tuned setup for people who don't have experience with suspension.

[Jackson]

Originally Posted by Soravia

With such drops on ride height (and reduction in suspension travel) and the marginal increase in spring rates, the car will be hitting the bump stops much harder on just about any road bumps.
Roads like we have in Texas are very horrible and limited and soft suspension will send the car losing grip all over the place, not to mention harsh ride due to strong impact with the bump stops.
Is Eibach going to come out with a properly tuned set (shocks, REAL stiff springs, matched bump stops)?
I just had Auto-X with Fat Cat Motorsports suspension equipped turbo Miata along with other Miatas running different setups. 800lb/500lb (OEM is around 190lb/120lb) FCM setup drove better (very neutral under hard cornering, hard braking, mid-corner braking and gas, small body roll, almost no bounce), posted better times and rode better over the bumps. (FCM setup can be used with choice selection of springs similar to Eibach Motorsports springs match with custom valved shocks)
I know Eibach actually sells 2.5" ID springs for such applications. I hope there's more focus on those than the horrible "Lowering Springs" that reduce ride quality without substantial performance gain.

Horrible Eibach for people who don't understand suspension working.
http://performance-suspension.eibach...rmance_springs

Real Performance Eibach for professional people who know what they're doing.
http://performance-suspension.eibach..._spring_system

I just hope there's a complete tuned setup for people who don't have experience with suspension.

The Pro Kit and Sportline spring kits are entry level suspension upgrades tuned for moderate street use. You're not going to win the Pirelli World Challenge on a Pro Kit. However, the performance of the car IS increased over stock and our kits include bumpstops to replace the factory bumpstops. There are multiple reviews of our Pro Kit and Sportline floating around the forum that are worth reading.

We are currently developing adjustable sway bars and coilovers for the FR-S and BRZ. We will offer three types of coilovers that will all use our ERS motorsport springs.

Pro Street-S
Mono Tube design, ERS springs, height adjustable only, camber plates optional.

Multi Pro R1
Mono Tube design, ERS springs, height adjustable, single adjustable rebound/compression (7 clicks) on the shaft, camber plates optional.

Multi Pro R2
Mono Tube design, ERS springs, height adjustable, adjustable rebound (7 clicks) on the shaft, adjustable compression (10 clicks) on a remote reservoir, camber plates optional.

Each of these kits will allow for spring rate changes for anyone really trying to dial in their particular set up for street, track or both.

[Soravia]

Thanks. I hope you promote those ERS kits more so people don't misunderstand from word of mouth that the lowering springs or some adjustable kits like Raceland are the best option for their money. It doesn't have to be a dedicated race car to enjoy great suspension setup.

[Jackson]

For sure we will. Just waiting for the final specs from R&D so we can start posting info.

[gmookher]

Originally Posted by Esoteric

T
If your coming from say, a well setup BMW, the FRS feels over-sprung in the rear. This is my personal feeling of the FRS rates as well.
This isn't to say that BMWs don't often have a lot of rear rate too, its just different from tuner to tuner, driver to driver.
.

x2

[Esoteric]

So far I have spent:

-LOTS of time on stock (FRS), thousands of street and hundreds of track miles

-1 hour on Eibach sportline + OE dampers (FRS)

-2 Hours on stock + spherical rear control arms

...About to install Hotchkis springs on OE dampers

Right now, I like stock BUT... I haven't tested enough. So my reviews will be put off until we have more wheel time.

[Esoteric]

I'll have some more spring updates very shortly.

So far, the Hotchkis are impressive and more responsive than OE FR-S. The Eibach prokit have slightly less in the front but I like the ride of the PK better.
Much more front response and flat cornering from each, but both need the rear subframe bushings inserts from Whiteline or they are too oversteer prone.

Further review and explanation coming soon.

[Cope52]

Interestingly, C/Ds long term BRZ they took the car to a shop and had the spring rates measured--182F. 170R--very close to RCE's measurements.

http://media.caranddriver.com/files/...lete-specs.pdf