[stretch]

Originally Posted by evilSTi7

yea, i know the bottom coils are supposed to bind (and they were that way when the car was just sitting). It's been a while since i removed the tanabe's but i might still have pictures of them after i uninstalled them. I'll see if i can dig them up.

I wonder if Tanabe went through a revision just as RCE is doing, with the earlier springs (yours) having the problem.

Originally Posted by BoostJunkie

I would say that the bottom line is that NO product is perfect the first time it comes out.

There's a difference between not being perfect (there is no such thing, since all products are a compromise) and having a fundamental, crucial, and unnecessary design flaw.

These springs went through extensive testing and many prototypes before we were satisfied with the results.

But nobody used a tape measure? This is really basic stuff.

Originally Posted by RaceComp Engineering

I can say that many times in the 5 months I tested them on my STI that I never experienced this.

I've been PM'd be a few individuals that are experiencing frequent coil bind. For whatever reason, those owners do not want to post in this thread. I've been told the RCE springs bind frequently on most autocross courses and even on the occasional subtle dip in the freeway- basically, it's possible on any road not "billiard table smooth" (not my words). One individual found his rubber coil insulators completely split off, which I suspect made the thud (and thus the problem) much more obvious for that person to detect. Perhaps other people will realize the severity of their problem when their rubber insulators wear and split.

I don't expect nor want people to take my word for it though, that's hearsay. Hopefully those people will chime in themselves.

Regardless, I now have some measurements.

I'm told the coils of the RCE springs are 18mm thick. There are 5-6 of them vertically depending on where you measure (5.75 winds), for a total of 108mm to 90mm. That's 3.5 inches at their shortest side and 4.25 inches on their longest side. Recall from the first post that a spring needs to be able to compress to roughly 2-5/8 inches, and you see how far away the RCE springs are from where they need be. They're not even close.

To give you an idea of how bad this is, the distance from the upper and lower spring perches is 8.25 inches at their absolute longest point. (I originally said 8 inches, it's 8.25.) If these measurements are correct, the RCE springs compress to 4.25 inches there, meaning that you have only four inches of suspension travel before coil bind. Frankly, I'm surprised the coils aren't completely bound at ride height. Look at the strut:



I also have measurements of Prodrive springs. They use 4.5 coils at 14.8mm, for a total of roughly 74mm at coil bind at their longest part- within 4mm of the stock length and within spec. This would allow for 5.35 inches of suspension travel, more than the stock struts have even on the softer Prodrive bump stops. Unfortunately, though, they may still be inadequate for a longer travel aftermarket strut.

Here's the scary part: even with a 3/4 of a coil removed from the RCE springs, (to get the springs down to 5 coils), you'd still have a spring that becomes bound at a length greater than would be required. You'd have to get closer to the 4.5 winds, not 5, and simultaneously reduce the coil diameter or use a barrel shaped spring. I imagine that the removal of a coil necessitated thinner coils, but by how much?

So, the measurements I've been given indicate that even the revised RCE springs may have problems where a Prodrive or stock spring will not. It depends on how drastic and numerous the revisions were. Even if the revised design is sufficient for those on stock struts with stock bump stops, measurements will be of utmost importance for those on aftermarket struts or cut bump stops. The same goes for any other brand of spring.

So, RCE, what do you say the old and revised springs compress to? You keep saying you did an extensive amount of engineering, so surely these numbers are laying around somewhere. Why not end any confusion by providing the appropriate measurement of when your springs becomes fully bound?

[BlueGold]

Originally Posted by Rootus

For this very reason, I am torn between getting a GC setup, or waiting for Prodrive to release the RB320 pieces. Prodrive is slooooooow, but it seems to me like they do spend some time engineering things to work together.

Prodrive or STi (Japan). Out of all the lowering springs available for the STi...which one comes with new bumpstops?? Remember that when shopping for aftermarket parts.

[Mykl]

Originally Posted by stretch

Here's the scary part: even with a 3/4 of a coil removed from the RCE springs, (to get the springs down to 5 coils), you'd still have a spring that becomes bound at a length greater than would be required. You'd have to get closer to the 4.5 winds, not 5, and simultaneously reduce the coil diameter or use a barrel shaped spring. I imagine that the removal of a coil necessitated thinner coils, but by how much?

...and we now see the drawbacks of the inverted strut design and manufacturers that won't straight up tell us exactly what we're buying. If people knew all of this to begin with, and had non inverted struts to use, dealing with this would be as simple as purchasing the appropriate length bump stops to prevent spring bind.

But since we can't do that, our only option is to trust that we're being sold a good product and be willing to purchase another set of $300 springs after we've ruined the set we've already paid good money for.

RCE, if you're going to sell aftermarket lowering springs and advertise them as "designed for Ohlins replacement struts, and stock struts" I think you either need to provide bump stops for both strut applications that protects the springs you're selling.

[Splash]

That's not entirely fair...

Out of all the lowering spring available for the STi, the Prodrives are probably the softest, making the inclusion of the shorter/softer bumpstops more of a simple logic thing rather than proof of better engineering.

If you want Prodrive engineering, look no further than their rebadged AEM cold-air intake... Yeah, I bet they spent a LOT of time on that...

[05_GD7]

Or Scopion muffler

[TheHammer]

C'mon keep this thing going I just purchased the new Yellows and dont want my suspension all ganked up.
Myles-Dan-Andrew- Someone set our mingds at ease here!

Hamm er

[RaceComp Engineering]

Originally Posted by TheHammer

C'mon keep this thing going I just purchased the new Yellows and dont want my suspension all ganked up.
Myles-Dan-Andrew- Someone set our mingds at ease here!

Hamm er

We will have some info shortly. Hang tight.

Myles

[05_GD7]

I'd like to know the same for the new "regular guy" springs that I have my name on the list for - I'm paying a premium for these over the Prodrives - and I'm hoping for superior results.

[RaceComp Engineering]

This morning Myles got on a conference call with our rep and an engineer at the manufacturer and was able to get all of the vital information on the revised springs. I have the spec sheet here in front of me and everything is looking very good. The following are the specs that are relevant to this conversation:

2nd Gen. Yellows:
Wire Diameter - 13.50mm
Total Coils - 4.80
Solid Length - 71.34mm

Blacks (Regular Guy):
Wire Diameter: 13.75mm
Total Coils: 5.00
Solid Length: 78.38mm

We have also decided to include shortened bumpstops with all of the new springs. I hope this helps to put some of you at ease. We are still in the process of getting more information from the manufacturer as far as the reasoning for the old design, but at this point I think it is important to move forward and focus on the new design.

-Dan

[RaceComp Engineering]

Also, in regards to comparing our springs to the Prodrives, you have to remember that our rates are significantly higher, and therefore it will take a lot more force to cause them to approach full bind.

-Dan

[La Mer]

Big thanks to Stretch for bringing up this issue, and the bump-stop issue. It also shows how great RCE is for not turning their shoulder, and continuing to grow with the Subaru community!

[Splash]

Originally Posted by RaceComp Engineering

Also, in regards to comparing our springs to the Prodrives, you have to remember that our rates are significantly higher, and therefore it will take a lot more force to cause them to approach full bind.

-Dan

That's true, but unless you're confident enough in those rates to advise removal of the bumpstop, the issue is just as likely to happen...

Prodrive may be softer, but their shorter stops means they have further to go to get there.

[RaceComp Engineering]

Originally Posted by Splash

That's true, but unless you're confident enough in those rates to advise removal of the bumpstop, the issue is just as likely to happen...

Prodrive may be softer, but their shorter stops means they have further to go to get there.

I mentioned in my previous post that we will now be including shorter bumpstops with the new springs

-Dan

[05_GD7]

Shortened stockers? Or shorter different kind?

So given these numbers that RCE just posted....thanks for that by the way....If I'm using the RCE "regular guy" spring on stock dampers, what will happen first? Bumpstops or coil bind?

[lackskill]