Eibach Pro-Kit vs RCE Yellow

[Dave-ROR]

Originally Posted by Turn in Concepts

I guess it really depends on what you want. If you are looking for outright grip and lap times on a road course I think the RCE would be a bit better. Lowering too much on a strut based car is never a good thing especially when strut travel is limited and non adjustable.

Tony

Correct on lowering too much, but 20mm to 25mm IMO isn't the difference of "OK" to "Too much".

I like a looser car so IMO the RCEs would be a much worse setup for me, but I haven't tested them. If RCE wants to send me some I'll datalog and compare.

[wheelhaus]

A closer comparison would be RCE and Swift BRZ springs, which I'm personally torn between. They both offer less than 1" drop, same 4.5 rate for the rear, but the Switf BRZ are slightly softer up front.

[Jackson]

Originally Posted by Dave-ROR

Correct on lowering too much, but 20mm to 25mm IMO isn't the difference of "OK" to "Too much".

And depending on the motion ratio - 5mm does NOT equal 5mm less travel at the shock.

[RYU]

Originally Posted by Jackson

Again, this is all relative. I would love to hear your personal on track driving impressions of both kits. Have you driven and tracked both the RCE and Eibach springs?

I haven't tracked on the Eibachs but I have 7000 street miles on the RCE and about 30 or so laps on my local tracks (not a lot, I admit). In my case, the problem isn't the performance of the springs.. it's the bottoming out of the stock shock. My RCEs already bottom out on the bumpstops (which they provide their own) @ a conservative 20mm drop. I can only imagine any lower than 20mm would increase the chances of bottoming out even further. Those rear shocks are REALLY short.

If the stock shocks had better high speed compression damping you can better argue the merits of each spring. To me the RCE 20mm drop and square 4.3k/4.3k setup is better for my driving style so that's subjective but is an additional 5mm drop bad? On a really bumpy track.. probably?

On a different, can someone confirm if the Eibach is more progressive than the RCE. I thought they were.

[Jackson]

The Pro-Kit is 50lbs softer up front and 24lbs stiffer in the rear than RCE yellows.

The Pro-Kit is advertised at a 1" drop (25mm) but people are reporting only 7/8" (22mm). The 2mm gap at the wheel is probably less than a millimeter of lost travel at the shock.

The specs of both RCE and Eibach springs are great. Just different. Both work and both will add performance gains. I'm just posting facts because, of course, this is the internet and not everything on the internet is fact.

Technically, both springs are progressive but that's only to achieve the ride height for each kit. Once you get to static height the springs become linear.

[itisthumper]

Originally Posted by wheelhaus

You're gonna get a lot of flak for this, springs are a commonly discussed topic and can quickly be searched for lots of info.

To prevent this from turning into another "OMG forum etiquette" thread, what are you looking to achieve besides a mild drop? Looks only? Track days?
The specs of each spring set are really easy to find, so what kind of comparison are you looking for?

I'd never make a thread like this without searching first

Originally Posted by Jackson

I disagree with the Eibach springs not increasing performance. Both springs will increase performance...just in different ways. Not every driver will set up their cars the same way. It's like saying your car is wrong because it's painted blue and not black.

The RCE springs are more of a square set up with similar front and rear rates.

The Eibach springs have a rear biased spring rate like the OE BRZ and FR-S springs do.

The difference comes down to driver preference. Ironically, the RCE springs are made by Eibach as mentioned in their post below. You can't go wrong with either.

http://www.ft86club.com/forums/showt...?t=9936&page=2

I will rarely track it, if ever... I still want good performance though but Im not sure which setup I prefer without first-hand experience. So far, Im leaning towards the pro-kits because I can get them for $200 shipped, and they drop the car slightly lower.

Im not into drifting anything, just traditional apex-cornering. Since the pro-kits are stiffer in the rear and softer in the front, Im assuming it will have frs-like handling characteristics (as opposed to brz)

[Smudgeous]

Originally Posted by itisthumper

I'd never make a thread like this without searching first


I will rarely track it, if ever... I still want good performance though but Im not sure which setup I prefer without first-hand experience. So far, Im leaning towards the pro-kits because I can get them for $200 shipped, and they drop the car slightly lower.

Im not into drifting anything, just traditional apex-cornering. Since the pro-kits are stiffer in the rear and softer in the front, Im assuming it will have frs-like handling characteristics (as opposed to brz)

Looking at purely the spring rate ratios, the FRS rear spring rate is ~165% firmer than the front (3.8k vs 2.3k). The BRZ rear spring rate is ~130% firmer than the front (3.5k vs 2.7k). The Pro Kit rear spring rate is ~136% firmer than the front (4.9k vs 3.6k)

This means the Pro Kit is closest to the stock BRZ spring rate ratio, but slightly more oversteery (though not anywhere near as much as the FRS).

[itisthumper]

It seems the equal balance for the RCE yellow would cause a lot of understeer, no? Is it really better for the track?

[FRSFirestorm]

Originally Posted by Smudgeous

For your BRZ, the RCE Yellows are 66% firmer in front and 28.5% firmer in the rear, and the drop is roughly 3/4 of an inch all around.

The Eibach are about a full inch all around, and as Jackson stated, keeps a rear bias (33% firmer in front, 40% firmer in rear).

Personally, I liked that the Eibachs matched the stock setup's spring rate ratio more, and offered a tiny bit more drop. From what I remember reading about spring rates in RWD cars, firmer rear rates increase your ability to slide the tail, which is something I wanted after putting wider, stickier tires on my new wheels that I installed at the same time.

While I'm sure there's not a significant difference between the 2, my guess is that the RCEs would make oversteering a tad more difficult, which is probably better for speed on a track, but less fun when you want to get sideways.

This is the basic logic I followed and why I chose the Eibach's.

[Captain Insano]

I'm glad this thread was started so thanks OP.

I was wondering about this topic in another thread (I was off topic in that one) and this question never really got answered. I currently have the Eibach pro-kit springs and really like the feel of them, but have only used them on the street so far.

[Racecomp Engineering]

Originally Posted by itisthumper

It seems the equal balance for the RCE yellow would cause a lot of understeer, no? Is it really better for the track?

The RCE Yellows do not cause a lot of understeer. Yes the front rates are firmer than most but we did this because the front and rear of the car are not the same suspension design. So it's a little more complicated than simply keeping the same spring rate ratio as stock or increasing the stock rates by 15%. The front of this car benefits greatly from firm spring rates, especially when you lower the car even a little bit. With RCE Yellows it's very fast, easy to drive, and a lot of fun.

I do think Eibach springs are fine FWIW.

- Andrew

[whataboutbob]

I noticed a reduction in understeer after mounting the RaceCompEngineering springs along with a bunch of Whiteline stuff and getting an alignment.

[RYU]

I just completed a buffet style track day @ Streets of Willow yesterday. My only mods to the entire car are HP+ front brake pads and RCE yellows. What a fun car.

It's properly neutral imho. Any adjustments to understeer/oversteer was made easily by adjusting tire pressures (+-2 to 4psi). I was able to induce long drifts on the skidpad no problem but could also induce a lot of push in the front if needed. Its when the car does these things when you don't want it to is when it becomes a problem. I had about 2.5hrs of all-you-can-drive track time . Awesome. I hope more track day coordinators take note. I'll pay more for no run groups!

Once I kill these Prius tires is when i'll look into coilovers and more adjustment. The RCE yellows are an excellent Stage 1 mod.

[autobrz]

If a car is already perfectly setup, then a stiffer front spring will introduce more understeer. But a stock BRZ/FRS with zero camber and macpherson struts in front will benefit greatly from stiffer front springs to keep body roll and camber loss to a minimum.