Best springs for performance?

[Dave-ROR]

Originally Posted by ultra

I've got the Whiteline Com-Cs, camber bolts and rear camber bushings plus some Eibach Pro Kit springs lying around in my storage room right now, and some RCE Yellows on the way to complete the Starter Kit setup.

I'm planning on driving the car as much as I can until my trusted mechanic/alignment guy gets back in mid-September so I'll post up a review on the RCE Yellows then.

Will probably skip installing the Eibachs altogether and just sell them on in favour of the RCE Yellows + starter kit since the RCE starter kit was developed as a package. Unless somebody can bribe me to go through the additional effort amd $$$ of two spring installs for the sake of a baxk to back comparison.

Also, I suspect that an alignment will influence handling in addition to just springs, which gives people another variable to consider.

Doesn't make sense to not try it out IMO.

The RCE is a equal rate setup, who knows you might like the stiffer rears more. :shrug: If you have them, I'd try them out. :shrug:

[ultra]

I'd have loved to but it's all down to my alignment guy not being in town at the moment. Only so many folks here I can trust to do a good job.

[gmookher]

Originally Posted by ft86Fan

Why is the drop more in the rear than the front? Wouldn't that mess up the rake? Thanks.

this happens to work well with the wl rear crossmember bolts, my h&r are the same way


h&r bias is for brz
grab a calculator and do your arithmatic

[kendalldwhite]

im waiting for hitchkis springs and sways to come in, i read up on the forum and i thought hotchkis was the way to go at this point

[gmookher]

I know its primitive, but do you guys even calculate bias? It a may be helpful to build a chart, off of that chart that lists all the spring rates. Easy way to tell a drift from a race setup. STuff with Bias like 1:1 like the RCE and many coil overs are not for drift. When you see a front to rear bias of say 0.63, that is more likely to be drifty. fwfw. the oe bias of the brz is like .77. iirc, the FRS is in the 0.60's

while this isnt always the case as everything can be changed with dampers and bars, still..just saying, idiot guide

[rikdrt1]

im interested in the SWIFT as well - someone let us know when they become available.

[RedLeader]

Originally Posted by gmookher

this happens to work well with the wl rear crossmember bolts, my h&r are the same way


h&r bias is for brz
grab a calculator and do your arithmatic

None of your math, Mook! You take that devil worship elsewhere, where people with braincells appreciate that kind of nonsense

:happy0180:

[Racecomp Engineering]

Originally Posted by RedLeader

None of your math, Mook! You take that devil worship elsewhere, where people with braincells appreciate that kind of nonsense

:happy0180:

Honestly...it's much more complicated than that.

If two springs have a front/rear ratio of .7, they still might handle completely different and have a different balance, even if all else is the same.

175/250 and 350/500 will behave very differently and have a very different balance, beyond just less roll for the firmer set-up.

The front and rear do not react exactly the same to changes in spring rate. So if you take the stock spring rates and simply make them 10% stiffer, you're NOT keeping the stock balance. A lot of people (and tuners) still don't understand this.

With our RCE Yellow springs, we went a lot firmer up front than everyone else. Some will think that means we shifted the balance of the car, but in reality...the front with a macstrut needs a lot more help than the rear of the car. Plus it means you can put power down easier coming out of corners (helpful with the torsen rear diff) and have a more stable car that also has excellent turn-in and balance. The front of the car has vastly different geometry and does not have the same camber curve of the rear.

EDIT: and on top of all that, you can throw it all out the window when you drop the car 1.25 inches and are now cornering on the firm bumpstops. Those add spring rate of their own. Or....run RCE Yellows that include shortened bumpstops.

- Andrew

[Intake]

Can anyone confirm the ride comfort of these springs?

[frs10]

i heard a lot of good things about the RCE yellow

[ZDan]

Thing 1: Ride comfort is 1000X more a function of dampers than springs! Soft springs with piss-poor dampers will ride harsh. Stiff springs with excellent highly digressive dampers will ride MUCH more smoothly and comfortably, while better controlling pitch and roll. I just went from 9F 7R Tein SS coilovers to 11F/11R Ohlins DFVs on my RX-7, and the Ohlins are UNBELIEVABLY smoother-riding on the street, despite being a LOT (22%/57%) stiffer.

Thing 2: A 5k spring is a 5k spring, no difference between manufacturers other than consistency and accuracy (i.e., is "5k" really "somewhere between 4k and 6k"), susceptibility to corrosion, and fatigue life. I would stick with straight linear-rate springs, not a fan of progressive or multi-rate. For springs, I would pick a *known good-quality supplier* based on what rates I wanted.
One manufacturer's springs aren't going to feel more comfortable than another's of the same rate, and spring rate has WAY less impact on ride quality than damping characteristics.

Thing 3: Wheel rates are what are important. Spring rates are a means to get the appropriate/desired *wheel rates*. Front and rear motion ratios for the FR-S/BRZ are ~0.95 and ~0.75 (as far as I've gathered), and wheel rate is spring rate multiplied by the SQUARE of the motion ratio. If you run same-rate springs all around and you'll have 61.6%/38.4% relative front/rear stiffness at the wheels. In my opinion, that's too much front bias.

Some front-bias will work, but often automakers give a little more rear spring stiffness relative to weight distribution to have slightly higher rear frequency so that at speed, when you hit a bump the two "settle" at close to the same time even though the front hit the bump first. Then they balance the handling toward understeer with sway bars and alignment settings.

Stock FR-S *wheel rates* are right at 50/50 front/rear (spring rates 2.4 kg/mm front, 3.8 kg/mm rear).
Stock BRZ *wheel rates* are ~56/44 (spring rates 2.8kg/mm front, 3.5kg/mm rear)
So their wheel rates bracket the weight distribution, which is ~54/46 - 53/47 with driver and fuel.

I don't think there's anything about MacPherson struts that makes them "need" relatively more spring or wheel rate, and neither did Subaru or Toyota/Scion.

My .02!

[Racecomp Engineering]

Originally Posted by ZDan

Thing 1: Ride comfort is 1000X more a function of dampers than springs! Soft springs with piss-poor dampers will ride harsh. Stiff springs with excellent highly digressive dampers will ride MUCH more smoothly and comfortably, while better controlling pitch and roll. I just went from 9F 7R Tein SS coilovers to 11F/11R Ohlins DFVs on my RX-7, and the Ohlins are UNBELIEVABLY smoother-riding on the street, despite being a LOT (22%/57%) stiffer.

Thing 2: A 5k spring is a 5k spring, no difference between manufacturers other than consistency and accuracy (i.e., is "5k" really "somewhere between 4k and 6k"), susceptibility to corrosion, and fatigue life. I would stick with straight linear-rate springs, not a fan of progressive or multi-rate. For springs, I would pick a *known good-quality supplier* based on what rates I wanted.
One manufacturer's springs aren't going to feel more comfortable than another's of the same rate, and spring rate has WAY less impact on ride quality than damping characteristics.

Thing 3: Wheel rates are what are important. Spring rates are a means to get the appropriate/desired *wheel rates*. Front and rear motion ratios for the FR-S/BRZ are ~0.95 and ~0.75 (as far as I've gathered), and wheel rate is spring rate multiplied by the SQUARE of the motion ratio. If you run same-rate springs all around and you'll have 61.6%/38.4% relative front/rear stiffness at the wheels. In my opinion, that's too much front bias.

Some front-bias will work, but often automakers give a little more rear spring stiffness relative to weight distribution to have slightly higher rear frequency so that at speed, when you hit a bump the two "settle" at close to the same time even though the front hit the bump first. Then they balance the handling toward understeer with sway bars and alignment settings.

Stock FR-S *wheel rates* are right at 50/50 front/rear (spring rates 2.4 kg/mm front, 3.8 kg/mm rear).
Stock BRZ *wheel rates* are ~56/44 (spring rates 2.8kg/mm front, 3.5kg/mm rear)
So their wheel rates bracket the weight distribution, which is ~54/46 - 53/47 with driver and fuel.

I don't think there's anything about MacPherson struts that makes them "need" relatively more spring or wheel rate, and neither did Subaru or Toyota/Scion.

My .02!

Thing 1: I agree that dampers are more important for ride comfort, but with lowering springs we're usually talking about ride comfort problems due to a lack of bump travel and that's still very much a thing. The rates themselves are not as important (and you're on the bumpstops or bottomed out most of the time anyway with the big drop springs.

Thing 2: Agreed....BUT the consistency and accuracy thing is a real concern sometimes.

Thing 3: You should drive a car with our springs. On the stiffer end spectrum of spring rates on coilovers on a more dedicated car I would generally go with a firmer rear, but on the soft end with OEM fitment lowering springs you're fighting roll so much that the firm front helps so much. Even with medium rates (the default on our coilovers) we've found that our car is faster with a good bit more front wheel rate, at least for how we have set it up.

- Andy

[hanabie]

please kill this thread! a year old!

[OICU812]

Originally Posted by ZDan

Thing 1: Ride comfort is 1000X more a function of dampers than springs! Soft springs with piss-poor dampers will ride harsh. Stiff springs with excellent highly digressive dampers will ride MUCH more smoothly and comfortably, while better controlling pitch and roll. I just went from 9F 7R Tein SS coilovers to 11F/11R Ohlins DFVs on my RX-7, and the Ohlins are UNBELIEVABLY smoother-riding on the street, despite being a LOT (22%/57%) stiffer.

Thing 2: A 5k spring is a 5k spring, no difference between manufacturers other than consistency and accuracy (i.e., is "5k" really "somewhere between 4k and 6k"), susceptibility to corrosion, and fatigue life. I would stick with straight linear-rate springs, not a fan of progressive or multi-rate. For springs, I would pick a *known good-quality supplier* based on what rates I wanted.
One manufacturer's springs aren't going to feel more comfortable than another's of the same rate, and spring rate has WAY less impact on ride quality than damping characteristics.

Thing 3: Wheel rates are what are important. Spring rates are a means to get the appropriate/desired *wheel rates*. Front and rear motion ratios for the FR-S/BRZ are ~0.95 and ~0.75 (as far as I've gathered), and wheel rate is spring rate multiplied by the SQUARE of the motion ratio. If you run same-rate springs all around and you'll have 61.6%/38.4% relative front/rear stiffness at the wheels. In my opinion, that's too much front bias.

Some front-bias will work, but often automakers give a little more rear spring stiffness relative to weight distribution to have slightly higher rear frequency so that at speed, when you hit a bump the two "settle" at close to the same time even though the front hit the bump first. Then they balance the handling toward understeer with sway bars and alignment settings.

Stock FR-S *wheel rates* are right at 50/50 front/rear (spring rates 2.4 kg/mm front, 3.8 kg/mm rear).
Stock BRZ *wheel rates* are ~56/44 (spring rates 2.8kg/mm front, 3.5kg/mm rear)
So their wheel rates bracket the weight distribution, which is ~54/46 - 53/47 with driver and fuel.

I don't think there's anything about MacPherson struts that makes them "need" relatively more spring or wheel rate, and neither did Subaru or Toyota/Scion.

My .02!

Ohlins are 6K/6K square. I understand and respect your work on the math, but what they've done and what RCE have done for feel and performance with a square spring set is well....proven real world so it does work with good results?