Thinking about suspension replacement again - RX8Club.com



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Old 02-14-2016, 08:24 AM   #1  
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Thinking about suspension replacement again

My 2009 RX-8 GT is 7 years old this March. It has about 50,000 miles. I'm thinking it's going to be time to do something with the OEM dampers soon. I should also mention that I have the Racing Beat front and rear anti-roll bars. I know many here are not fond of thicker bars, but it was an inexpensive way to improve handling, reduce roll, and improve steering response until I was ready to replace the OEM dampers.

I've gone back and forth with options over the years. Originally, I had planned on the Ohlins, but with my family situation, I'm having a hard time justifying the price (which could cover a small family vacation, significant house repairs/upgrades, etc.). My other consideration is the really shitty roads and steep driveways in mid-Michigan (we are constantly rated as having some of the worst roads in the entire country). So I'm looking for something that will result in a tolerable ride (preferably a bit better than OEM), but be OK for the occasional track day. I don't really care about adjustability--I just want dampers matched to springs, with between about 0.5 and 0.75" of lowering.

That gets to my other concern with many of my options: Almost all coilovers lower the car at least a full inch. That's the case with Ohlins (if you want the same lowering front and rear), and appears to be the case with the Bilstein PSS9s. Because of this, I've been leaning heavily toward Koni Sports (with their 0.5" of lowering) combined with the OEM springs. However, I've also read that their damping can vary quite a bit from unit to unit. Additionally, the Koni Sports I had on my 2005 Mazda3, while they handled great, were brutal on our terrible roads, even on the softer settings. Still, this setup is one of my top contenders--no worrying about ride height adjustability and getting it correct at each corner, Konis are high quality dampers, and they're cheap (and I don't have to buy springs).

One of the others that I constantly come back to is the Bilstein PSS9 setup. It's also relatively inexpensive, and from what I've read, a good quality choice, and the dampers are probably pretty well matched to each other. They're supposed to be a good all-around option for what I'm looking for. My main concern: the amount of lowering. Depending on the source, it appears to be either 15mm or 30mm of lowering, minimum. 15mm would be fine. 30mm is too much. Does anyone know what this number is for the RX-8?

The other one I'm considering is Feal Suspension. I know that typically these oddball brands are not great, but Brian Goodwin has great things to say about this particular brand on Miatas. They also use Swift springs, which is probably a good thing. The 30 levels of adjustability is silly, though, and I'm mostly concerned about long-term reliability with this brand. I'm NOT concerned with that for Koni or Bilstein dampers. One of the things I like about Feal (other than Brian Goodwin's recommendation): They can go all the way up to OEM ride height. They also cost $1400--about the same as the Bilstein PSS9 kit at Tire Rack.

Thoughts?

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Old 02-14-2016, 08:37 AM   #2  
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If you read this thread: https://www.rx8club.com/rx-8-racing-...ns-fcm-260594/ You'll see that Steve's recommending the Bilstein PSS (non-adjustable) setup for an inexpensive coilover, as it'll be better than anything in that price range and the adjustability on the PSS9's are largely a marketing gimmick, with very little effect on the damping.
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Old 02-14-2016, 08:45 AM   #3  
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EDIT: Let's start over.

I must not have read the entire thread. The PSS (B14) sounds like what I want, other than the fact that it may lower the car a bit more than I would like at 25-30mm. I just need to find someone who sells them. Brian Goodwin can probably get them, but his price for the B16 is $400 more than Tire Rack's price.

EDIT: I see that eshocks.com (which is a store near me) sells them for $1,262.

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Old 02-16-2016, 12:45 PM   #4  
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OK, another thought has occurred to me after further research. I like the idea of Swift Springs (0.8" of lowering, which is perfect for me) combined with Bilstein HD (B6) or SP (B8) dampers. Bilstein shows the B6 dampers for the Series II RX-8, but the part numbers are the same as for the Series I RX-8 years. They don't list the B8s at all for Series II, but they do for Series I. The Swift Springs part number is the same for all years of RX-8, including Series II, so I'm guessing that in both the cases, Bilstein and Swift, I would be buying basically Series I components for my Series II. That is, the rear spring perch would be converted to Series I position.

I'm thinking that as long as I go with dampers and springs for Series I, this is not an issue, just as if I were buying a coilover kit, right?

I would prefer the B8 Sport dampers from Bilstein. I suspect that the focus on the B6s is more comfort than sport, which is fine for a VW Jetta, not so much for my RX-8.

EDIT: After doing some research, I don't think there would be a problem with using the B6 HD dampers. It sounds like the main difference between the B6 and B8 is just stroke length, and the B6 is probably more appropriate for a spring that only lowers the car 0.8".

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Old 02-17-2016, 07:20 PM   #5  
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Bilstein PSS

I did some shopping around and was able to find the PSS kit for as low as $800 with a coupon and free shipping. I'll see if I can find that deal again. It is fairly common to find it for $1,000, but I suspect those outfits are just drop-shippers, so I would call Bilstein to find out if they are in stock before ordering.

Black2010R3 is correct about my thoughts about the PSS9 vs PSS. I think the PSS is a better setup, as the adjustability of the 9 actually robs performance from the shocks and is essentially useless for performance tuning. It is a gimmick that causes the shocks to under-perform their potential and costs more money doing it.

When set to the minimum lowering value, my PSS9s set the ride height to a little over 13.5", which looks pretty good and performs well. You can probably cheat that value 0.25" without any consequences.


Bilstein Sport/HD with Swift Springs

What are the part numbers on the swift springs?

In my experience, advertised lowering values are conservative, and the car always ends up lower than expected after settling. As an extreme example, I tried the Bilstein B12 kit (Bilstein Sport shocks and Eibach Pro-Kit springs) a couple of years ago, which has an advertised lowering of 1.2", and my car ended up 2.75" lower in the front and 2.0" lower in the rear. Swift makes very good springs and they should be fine with either set of shocks, but I would expect 1.0 - 1.2" of overall lowering in the end after the car settles. Also, the springs should be within about 20% of the OEM spring rates for the shocks to perform as designed.

It's a tough call. Good luck with it.



[BTW, your car is the BEST color ever conceived!]

.

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Old 02-17-2016, 07:23 PM   #6  
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Here is a photo of my car taken 1 month after installing my PSS9s with the heights adjusted to exactly the maximum values listed in the instructions.

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Old 02-18-2016, 03:18 PM   #7  
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Thank you for the input! I agree about the color.

The Swift Sport springs part number is 4Z008. I'm actually about to place the order for the Swift springs and Bilstein HD dampers. I'm a little nervous about getting it right, especially since the part numbers are the same for Series I and II, but I'm also looking forward to trying it out.

In my searching (I've done a LOT regarding similar setups, on the RX-8 and other cars), I found a thread here started by blacksheep515. He was trying pretty much the same thing I am with his R3. Unfortunately, he never updated that thread with the results.

I measured my stock ride height last year at just slightly under 15.5" from the center of the wheel to the lip of the fender. I'll measure again right before the install and then again after.

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Old 03-31-2016, 08:11 PM   #8  
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Quote:
Originally Posted by Chibana View Post
Thank you for the input! I agree about the color.

The Swift Sport springs part number is 4Z008. I'm actually about to place the order for the Swift springs and Bilstein HD dampers. I'm a little nervous about getting it right, especially since the part numbers are the same for Series I and II, but I'm also looking forward to trying it out.

In my searching (I've done a LOT regarding similar setups, on the RX-8 and other cars), I found a thread here started by blacksheep515. He was trying pretty much the same thing I am with his R3. Unfortunately, he never updated that thread with the results.

I measured my stock ride height last year at just slightly under 15.5" from the center of the wheel to the lip of the fender. I'll measure again right before the install and then again after.
Well, Steve, you were correct about the lowering. This Swift spring/Bilstein HD combo should have resulted in 0.8" lowering. It looks like I got about 1 3/8 inches front and about 1 inch rear. That's more than I wanted, but hopefully it will work out OK. The car looks great. I haven't driven it much, yet. At times the ride seemed a bit more compliant, and at other times harsher. It's hard to say, since I hadn't driven it since November. I'm excited to drive it more, but here in Michigan we're back into cold, nasty weather for the next several days. I still need to get the alignment done. I plan to do -1.75 degrees front and rear, if I can find a shop that can do it right. Most shops around here seem pretty clueless.
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Old 04-18-2016, 01:33 PM   #9  
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UPDATE:

When I got my car back from the shop that stored it for winter for me, they did not reduce the tire pressure back down to normal from the storage pressure, which is why the ride was off, and harsher than I was expecting. Once the weather got nice, I checked and adjusted the pressure, and now the car's ride is excellent. It's less busy and softer over broken pavement (which is almost ALL pavement here in mid-Michigan), and yet the steering feel still seems to have improved. The car handles very well, and after the alignment, where I had the front camber increased (negatively) by about 1 degree over Mazda's recommendation, the car's mid-corner understeer appears to be gone or at least greatly reduced.

Other than the greater ride height lowering than I wanted, I'm very pleased with this damper and spring choice, especially given the price. Although the car is lowered more than I wanted, it looks great at this height, not looking slammed, but not too high, as I always felt it looked from the factory (for this kind of car, at least).

Here are two photos I took yesterday after a wash, clay bar, and wax:
https://goo.gl/photos/kHsoHzi97sKMo8KU7
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Old 04-18-2016, 02:57 PM   #10  
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Looks great to me!
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