Anyone here run Bilstein PSS9's?
04-23-2010, 01:37 PM
#352
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See my edits below -- I used the wrong length for the PSS9 bump stops which I didn't realize until I ran across this earlier post:
Btw, I'm doing the 7K Swift spring install this Sunday. Should have a few pics up by Sunday night. 
...for the droop travel vs bump travel of the PSS9 coilovers.
Side Note: When starting from your static ride height, your droop travel is how much the shock can extend before the tire looses contact with the ground. Bump travel is how much the shock can compress before the bump stop prevents the suspension from compressing any further.
I posted these pics earlier in thread:
Total front shock travel (~5.5")
Total rear shock travel (~6.0")
From the PSS9 manual, these coilovers come with 40mm bump stops F&R -- which means that ~1.58" of each shock's total travel is taken up by the bump stop.
The rough measurements I got for F&R droop travel were as follows:
Front = 2.25"
Rear = 3.0"
From this my calculated F&R bump travel are as follows:
Front: 5.5" - (2.25" + 1.58") = 1.67"
Rear: 6.0" - (3.0 + 1.58") = 1.42"
So when our front and/or rear suspensions compress by ~1.4 - 1.67" we are into our bump stops. The rear isn't too concerning too me (due to the progressive spring used on that end), but I would definitely like more bump travel up front (before the spring rate effectively goes to infinity when we hit the bump stop).
The pair of 7K Swift springs I'll be installing will improve things, but I'm seriously considering ordering a pair of shorter bumpstops from Fat Cat Motorsports (36mm are the next step down, or I could go with a 12mm race version). As I still drive the car on the street (weekends), I might go with a pair of 36mm bumpstops, which will increase my front bump travel by ~1/6"...
Side Note: When starting from your static ride height, your droop travel is how much the shock can extend before the tire looses contact with the ground. Bump travel is how much the shock can compress before the bump stop prevents the suspension from compressing any further.
I posted these pics earlier in thread:
Total front shock travel (~5.5")
Total rear shock travel (~6.0")
From the PSS9 manual, these coilovers come with 40mm bump stops F&R -- which means that ~1.58" of each shock's total travel is taken up by the bump stop.
The rough measurements I got for F&R droop travel were as follows:
Front = 2.25"
Rear = 3.0"
From this my calculated F&R bump travel are as follows:
Front: 5.5" - (2.25" + 1.58") = 1.67"
Rear: 6.0" - (3.0 + 1.58") = 1.42"
So when our front and/or rear suspensions compress by ~1.4 - 1.67" we are into our bump stops. The rear isn't too concerning too me (due to the progressive spring used on that end), but I would definitely like more bump travel up front (before the spring rate effectively goes to infinity when we hit the bump stop).
The pair of 7K Swift springs I'll be installing will improve things, but I'm seriously considering ordering a pair of shorter bumpstops from Fat Cat Motorsports (36mm are the next step down, or I could go with a 12mm race version). As I still drive the car on the street (weekends), I might go with a pair of 36mm bumpstops, which will increase my front bump travel by ~1/6"...
04-25-2010, 09:37 PM
#353
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Swift spring install
Installed the pair of 7K Swift front springs today with the help of a friend:
In this pic you can see the stock 6K PSS9 front spring next to the 7K Swift spring. In the foreground is the stock 40mm PSS9 bumpstop.
To increase my bump travel, I decided to cut down the stock PSS9 bumpstops by 4mm, giving me a 36mm bumpstop (same length as the ones FCM offers for the MX-5/RX-8). 4mm ended up being just the tapered end of the bumpstop (I removed it from the stiffer end of each bumpstop).
The above pic shows the material that was removed.
Re-installed the front coilovers after lowering my spring perches by 5mm -- due to the Swift springs being stiffer they don't compress as much as the stock PSS9 springs under the weight of the car.
The installed coilovers are shown below-
Driver's Side
Passenger Side
General Thoughts - Drove home on shock settings of 5F/5R. The car still felt very composed -- no sensation of it being underdamped or "bouncy". I also noticed less front-end dive under braking. I'm really looking forward to testing out my "revised" set-up at my next autocross!
In this pic you can see the stock 6K PSS9 front spring next to the 7K Swift spring. In the foreground is the stock 40mm PSS9 bumpstop.
To increase my bump travel, I decided to cut down the stock PSS9 bumpstops by 4mm, giving me a 36mm bumpstop (same length as the ones FCM offers for the MX-5/RX-8). 4mm ended up being just the tapered end of the bumpstop (I removed it from the stiffer end of each bumpstop).
The above pic shows the material that was removed.
Re-installed the front coilovers after lowering my spring perches by 5mm -- due to the Swift springs being stiffer they don't compress as much as the stock PSS9 springs under the weight of the car.
The installed coilovers are shown below-
Driver's Side
Passenger Side
General Thoughts - Drove home on shock settings of 5F/5R. The car still felt very composed -- no sensation of it being underdamped or "bouncy". I also noticed less front-end dive under braking. I'm really looking forward to testing out my "revised" set-up at my next autocross!
04-26-2010, 09:58 PM
#354
Did an event at an old air strip yesterday. I dont quite agree with the course set up, but I will say that we hit the highest speeds ever for an autocross. Hit the limiter in 3rd! Someone left a tractor on the side of the strip, so we had to modify the course to compensate. Ended up that we had 900 ft from the end of a slolom to a pivot cone and then 900ft back, with very little turning in between. So you came out of the slolom then full throttle to the top of third, then slam on the brakes to almost stop. Then pivot cone and 900ft to the next element. Needless to say HP cars had a big advantage.
That being said, I cant complain about our results. Codriver paxed 2nd and I paxed 4th. I coned away a run that was .4 sec faster than my codriver that would have put me in 2nd and less than a second off the 1st place STI with a very good driver. I would say the STI gained at least a second in the 900 foot and back. Not to mention taking off from almost stop.
The surface is about medium grip asphalt. Was getting a little too much oversteer wit the 5/5, so went down to 6 in the rear and felt awesome. Ran pressures of 39/37. Next event is on very good asphalt so I am going to start at 4/5.
That being said, I cant complain about our results. Codriver paxed 2nd and I paxed 4th. I coned away a run that was .4 sec faster than my codriver that would have put me in 2nd and less than a second off the 1st place STI with a very good driver. I would say the STI gained at least a second in the 900 foot and back. Not to mention taking off from almost stop.
The surface is about medium grip asphalt. Was getting a little too much oversteer wit the 5/5, so went down to 6 in the rear and felt awesome. Ran pressures of 39/37. Next event is on very good asphalt so I am going to start at 4/5.
04-27-2010, 07:51 AM
#355
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Max,
The speeds of that course definitely sound more appropriate for a Solo Trials event than a Solo event. Congrats on the solid PAX finish by you and your co-driver despite the power handicap!
I drove my car some more in a "spirited fashion" and noticed a bit of bounciness in fast transitional maneuvers. Adjusted the fronts to a setting of 4, and the front end felt sharp/poised again. So with the 7K front springs, looks like I'll start out at 4F/5R at my next autocross.
The speeds of that course definitely sound more appropriate for a Solo Trials event than a Solo event. Congrats on the solid PAX finish by you and your co-driver despite the power handicap!
I drove my car some more in a "spirited fashion" and noticed a bit of bounciness in fast transitional maneuvers. Adjusted the fronts to a setting of 4, and the front end felt sharp/poised again. So with the 7K front springs, looks like I'll start out at 4F/5R at my next autocross.
05-02-2010, 10:08 PM
#356
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I got to autocross the car both days this weekend.
On Saturday, I instructed at my local SCCA region's annual solo school. Instructors got to do some runs at the end of the day, where I was able to turn FTD. Ran pressures of 39F/37R and shock settings of 4F/5R. Car felt very composed, even in the bumpy stuff, and the front-end dived less in braking and seemed more composed through fast transitions.
Today, I ran points event #2 with the DC region at Fedex Stadium. They were 13 in my class and there was even a trailered STX WRX that was brought in. I ran pressures of 39F/37R with shock settings of 3F/4R as the "B lot" we used today has medium-to-high grip asphalt. My best was a 42.8 which left me 3rd in class -- 0.1 seconds out of 2nd, 0.2 seconds out of 1st. Overall, I felt pretty happy with my final time as Ian Baker (pro solo national champion and has finished as high as 2nd at solo nats) won STS in his CRX SI with a best time 42.498. So running ~0.3 seconds off of Ian this early in the season is definitely encouraging.
The Swift Springs have definitely improved the car!
On Saturday, I instructed at my local SCCA region's annual solo school. Instructors got to do some runs at the end of the day, where I was able to turn FTD. Ran pressures of 39F/37R and shock settings of 4F/5R. Car felt very composed, even in the bumpy stuff, and the front-end dived less in braking and seemed more composed through fast transitions.
Today, I ran points event #2 with the DC region at Fedex Stadium. They were 13 in my class and there was even a trailered STX WRX that was brought in. I ran pressures of 39F/37R with shock settings of 3F/4R as the "B lot" we used today has medium-to-high grip asphalt. My best was a 42.8 which left me 3rd in class -- 0.1 seconds out of 2nd, 0.2 seconds out of 1st. Overall, I felt pretty happy with my final time as Ian Baker (pro solo national champion and has finished as high as 2nd at solo nats) won STS in his CRX SI with a best time 42.498. So running ~0.3 seconds off of Ian this early in the season is definitely encouraging.
The Swift Springs have definitely improved the car!
Last edited by chiketkd; 05-04-2010 at 08:49 AM.
05-02-2010, 11:34 PM
#357
Chike, any loss in ride quality with the higher spring rates?
I have not been having any luck around here
Local race here was canceled today due to weather (same weather that is effecting the oil clean up). Our Divisional was cancelled due to lack of interest, it now will just be a regional 1 day event. The school and event that I was going to attend a few weeks after the Div was cancelled because someone ran into the trees last event. Not real happy at this point.
I have not been having any luck around here
Local race here was canceled today due to weather (same weather that is effecting the oil clean up). Our Divisional was cancelled due to lack of interest, it now will just be a regional 1 day event. The school and event that I was going to attend a few weeks after the Div was cancelled because someone ran into the trees last event. Not real happy at this point.
05-02-2010, 11:53 PM
#358
Glad to hear the stiffer springs worked out for you Chike. I just installed some 560F/390R Hypercoil springs on some new shocks and the ride is MUCH stiffer than it was on my Stance GR+ coilovers. First event on them yesterday the car was loose...very loose, The shocks are double adjustable so I was experimenting alot with rebound and compression...still trying to get everything sorted out. Thinking of either going back to the OEM rear sway, or just taking it off completely.
05-03-2010, 08:01 AM
#359
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No perceivable reduction in ride quality. I do drive around on a front shock setting of 4 to keep the stiffer front springs properly damped.
Sorry to hear about your troubles getting seat time.
FWIW Mike, Isley ran spring rates of 500F/350R when he ran STX. He used the MS bar up front and no rear sway. As you have 390# rear springs, I'd pull the rear swaybar.
Sorry to hear about your troubles getting seat time.
Glad to hear the stiffer springs worked out for you Chike. I just installed some 560F/390R Hypercoil springs on some new shocks and the ride is MUCH stiffer than it was on my Stance GR+ coilovers. First event on them yesterday the car was loose...very loose, The shocks are double adjustable so I was experimenting alot with rebound and compression...still trying to get everything sorted out. Thinking of either going back to the OEM rear sway, or just taking it off completely.
05-05-2010, 07:55 AM
#361
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FYI- taking off one endlink accomplishes the same effect as removing the bar. I know our rear bar is very easy to remove but its something to keep in mind. Mike, what shocks are you running?
05-11-2010, 11:03 PM
#362
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Came across another interesting comment about Swift springs the other day on miata.net by Bill Schenker (5 time CSP runner-up in Pro Solo and Solo Nats):
http://forum.miata.net/vb/showpost.p...59&postcount=5
Originally Posted by actor
I will say this much: Swift springs are AMAZING! Four year old springs have ZERO sag and are within 0.02lbs. of their stated ft/lb. Hard to imagine something better!
05-12-2010, 09:13 AM
#363
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Had a couple hours of free time on Sunday so I got my PSS9 kit installed over the weekend. I just need to fine tune the ride height now. Due to time constraints I simply assembled the shocks with the perch height where Bilstein left it. This gave me fender to hub distances of 12.75/13.0 front and rear. It looks kinda rice and now I need to raise it up before I get it aligned. At least changing ride height is pretty easy.
Sadly, I've already started thinking about stiffer springs and a revalve. Assuming Chike is right about our front spring being a 6K (336lb) spring, I think I'll be getting a pair of the goodwin delrin adapters for 2.5" springs for the rear and putting the Bilstein 6K front spring and helper back there. To match it up front I'll go for an 8K (~450lb) front spring + helper. This will keep the F-to-R spring ratio the same as OE and the same as the PSS9.
OE 156/113
PSS9 336/240
My next setup: 453/336
Sadly, I've already started thinking about stiffer springs and a revalve. Assuming Chike is right about our front spring being a 6K (336lb) spring, I think I'll be getting a pair of the goodwin delrin adapters for 2.5" springs for the rear and putting the Bilstein 6K front spring and helper back there. To match it up front I'll go for an 8K (~450lb) front spring + helper. This will keep the F-to-R spring ratio the same as OE and the same as the PSS9.
OE 156/113
PSS9 336/240
My next setup: 453/336
05-12-2010, 09:49 AM
#364
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Miles,
FWIW, the front spring rate is supposedly a 340lb/in spring, which was very close to a 6K spring in my book. Also, the front spring dimensions are 70mm ID (2.75") x 203mm (8"). If you put this spring in the rear, you'll need to get the 70mm Delrin adapter (not the 2.5").
I'd seriously just run the kit as is for the rest of this season. Get adjustable swaybars and adjust the car's balance from there. My current wheel rates (swaybar rate + spring rate), are identical to someone running a 550lb front spring with the stock FSB, and a 340lb rear spring with no rear swaybar.
I'm very happy with the car's handling balance at this point and I'm seriously considering keeping this exact set-up through the end of my 2011 season (plan on going to Nats in 2011).
FWIW, the front spring rate is supposedly a 340lb/in spring, which was very close to a 6K spring in my book. Also, the front spring dimensions are 70mm ID (2.75") x 203mm (8"). If you put this spring in the rear, you'll need to get the 70mm Delrin adapter (not the 2.5").
I'd seriously just run the kit as is for the rest of this season. Get adjustable swaybars and adjust the car's balance from there. My current wheel rates (swaybar rate + spring rate), are identical to someone running a 550lb front spring with the stock FSB, and a 340lb rear spring with no rear swaybar.
I'm very happy with the car's handling balance at this point and I'm seriously considering keeping this exact set-up through the end of my 2011 season (plan on going to Nats in 2011).
Last edited by chiketkd; 05-12-2010 at 01:33 PM.
05-12-2010, 12:45 PM
#365
+1 on what Chike said. You may find that the combination of 8" 340 lkb springs + the adapter prevents you from reaching the ride height you are after. I had this problem on my FCM Bilstein setup - the rear was too high. It all depends on the compressed height of the helper spring and how far down the shock the spring perch can be adjusted.
05-12-2010, 02:24 PM
#366
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George, very good point about the car being raised with a stiffer spring. I encountered this when I went to the 7K front spring. I initially lowered my spring plates by 5mm, but had to lower them another 4-5mm to get back to my ride height of 13.5" all around. If I decide to up my front spring rate any higher in the future, I'll need to swap to a 7" long spring as the stock helper spring would be able to take up the slack.
Btw, a few more pointers Miles:
1) The conical rear spring (progressive) goes from an ID of 60mm at the bottom to ~100mm at the top. So the stock rear spring plates cannot accept a 70mm spring. You'll need to get a set of 70mm plates from Bilstein.
2) The conical rear spring is 10" (254mm) in length - so an 8" spring may be too short
Btw, a few more pointers Miles:
1) The conical rear spring (progressive) goes from an ID of 60mm at the bottom to ~100mm at the top. So the stock rear spring plates cannot accept a 70mm spring. You'll need to get a set of 70mm plates from Bilstein.
2) The conical rear spring is 10" (254mm) in length - so an 8" spring may be too short
05-12-2010, 02:56 PM
#367
^Also, it's not just the stiffer spring that is the problem. The conical springs nestle nicely int the little rubber doughnut against the bottom of the OEM upper perches. The adapter you need to make a cylindrical spring work sits between the spring and the upper perch, and adds space between those two pieces. So, even if you were to swap out to a cylindrical spring of the same rate, using the Goodwin adapters, the rear of the car will ride higher. Of course, you may be able to offset this (plus the height gained by the higher rate spring) via the lower perch but you may, or may not, have enough threads present to make it all work to your liking.
05-12-2010, 04:03 PM
#368
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I am definitely planning on running at least one whole season with the PSS9's untouched and the Hotchkis MX5 bars front and rear. I just had the wheels turning today and it looked like running the PSS9 front spring on the rear was a not too shabby idea.
There is still an 1.25"-1.5" of threads left below the rear perches as they sit now with the car at 13.0" in the rear, 13.75-14.0" is the height I want. With the delrin adapter and the shorter 8" 6K spring with the 4" helper it sounds like it should go on the rear just fine with plenty of room to adjust the ride height. Thanks for the heads up on the springs being 70mm not 65mm. I will make sure to remember that when it comes time to buy more parts. I guess the 70mm 7" 8K Swift spring along with helper springs and adapters will be on my list of things to buy for the front next year.
Thanks for all the great feedback and info.
There is still an 1.25"-1.5" of threads left below the rear perches as they sit now with the car at 13.0" in the rear, 13.75-14.0" is the height I want. With the delrin adapter and the shorter 8" 6K spring with the 4" helper it sounds like it should go on the rear just fine with plenty of room to adjust the ride height. Thanks for the heads up on the springs being 70mm not 65mm. I will make sure to remember that when it comes time to buy more parts. I guess the 70mm 7" 8K Swift spring along with helper springs and adapters will be on my list of things to buy for the front next year.
Thanks for all the great feedback and info.
05-12-2010, 08:38 PM
#369
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Sounds good Miles. If you have any other questions in the future, feel free to ask here or send me a pm. I have a bunch of info about these coilovers that was passed onto me by my engineering contact at Bilstein USA in Poway, CA.
05-13-2010, 07:50 AM
#370
Just as a data point, I coilover-ed my Koni yellows and am running 7" long 2.5" ID springs all around with rates of 550F/275R. Since I'm just sitting my threaded sleeves on top of the existing spring perch, the bottom of the spring sits about an inch above where the stock spring was at its lowest point and I'm only at about 14" ride height in the rear. This is with the aforementioned 7" spring, an upper spring adapter that I machined myself and a helper spring (no spacer between the two springs). So judging by the photos, with an 8" spring, a helper and the Goodwin adapter, you'd be pretty close to the limit of your ride height adjustment.
05-13-2010, 10:13 AM
#371
Just as a data point, I coilover-ed my Koni yellows and am running 7" long 2.5" ID springs all around with rates of 550F/275R. Since I'm just sitting my threaded sleeves on top of the existing spring perch, the bottom of the spring sits about an inch above where the stock spring was at its lowest point and I'm only at about 14" ride height in the rear. This is with the aforementioned 7" spring, an upper spring adapter that I machined myself and a helper spring (no spacer between the two springs). So judging by the photos, with an 8" spring, a helper and the Goodwin adapter, you'd be pretty close to the limit of your ride height adjustment.
I assume you don't get coil bind on the rear? I'm a bit surprised a 7" 275# spring doesn't bind at peak load.
05-17-2010, 10:05 AM
#372
This is similar to my experience with my FCM Bilsteins, although it sounds like I can get my lower spring perch a bit lower than your setup so I am able to get the car lower. 8" springs wouldn't work for me, at least at the right height I am after (which is fairly low) but 7" springs seem to work just fine, even with higher rates.
I assume you don't get coil bind on the rear? I'm a bit surprised a 7" 275# spring doesn't bind at peak load.
I assume you don't get coil bind on the rear? I'm a bit surprised a 7" 275# spring doesn't bind at peak load.
Judging by pictures of the Bilstein shocks, your spring perches are probably capable of getting almost an inch lower than mine because of the big tall lower perch that's welded to the Konis. I have to modify a few things on the lower perches to get my rear lower, and the front should improve when I make some spherical bearing top hats because I'm currently running a huge spacer similar to what comes with the PSS9.
05-17-2010, 01:39 PM
#373
Ended up having a dry event yesterday and did pretty well. Ended up second it pax. About .6 sec back from Kerry. Surface is very good asphalt. Ran the Bilsteins at 4/5 f/r with 39/37 psi in the Kooks.
I can see that i want a little more spring up front. Don't know if I want to spend any money of 400lb springs now, or just wait and get then revalved for next season.
I can see that i want a little more spring up front. Don't know if I want to spend any money of 400lb springs now, or just wait and get then revalved for next season.
05-17-2010, 02:48 PM
#374
Do you think I could get away with running a 7" 7k spring in the front? I can get a set for next to nothing.
Chike it looked like you had to lower your pearch about 10mm to get to the same ride height. That leaves about 15mm difference. And I run a little higher ride height than you right now.
Chike it looked like you had to lower your pearch about 10mm to get to the same ride height. That leaves about 15mm difference. And I run a little higher ride height than you right now.
05-17-2010, 03:38 PM
#375
7", 7k springs on the front is probably pushing things, although I don't know for sure.
Note that it's not just coil bind that should be a concern. Check this spec sheet for Swift springs:
http://www.swiftsprings.com/file/metric.pdf
Note that they list "usable stroke" and "max stroke" for any given spring. You should be able to make a rough assessment of how much stroke you will asking of your 7" 7k springs and compare it to the Swift data, although it would not surprise me to learn that the Swift springs have a larger operational range than other brands.
Note that it's not just coil bind that should be a concern. Check this spec sheet for Swift springs:
http://www.swiftsprings.com/file/metric.pdf
Note that they list "usable stroke" and "max stroke" for any given spring. You should be able to make a rough assessment of how much stroke you will asking of your 7" 7k springs and compare it to the Swift data, although it would not surprise me to learn that the Swift springs have a larger operational range than other brands.