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04-17-2003, 03:27 PM | #1 |
Scooby Specialist
Member#: 14717
Join Date: Jan 2002
Chapter/Region:
South East
Location: Road Atlanta
Vehicle:2002 WRX, WR Blue Complete n00b Racing |
The Prodrive springs / Koni inserts / Cusco camber plates thread
Hey gang:
Since I just did this, I thought it might be useful to crank up a thread (like some of the other 'definitive' coilover threads, etc.). It seems like quite a few people are looking at this option instead of going with coilovers. I'm going to try and give you as much info as I can so we can all benefit from this experience. I'm only aware of maybe one other person who has done this. Thanks in advance to GTguy, PaulTG, and all the other people who have come before me on NASIOC. This is a shameless ripoff of their work. First of all, let me extend props to Steve_D and Subaru of Gwinnett. Without their help, I could not have done what I did. Their Subaru Performance Group is dedicated to making our cars better, stronger, faster than the average Subaru. (insert Steve Austin bionic man dih-dih-dih-dih-dih here) I'm sure if you PM them or look them up in the Southeast region they'd love to talk with you. About me: I'm 35 years old, have owned a ton of different cars, and love my WRX more than any of them. It's a 'fun' car for me. I drive a bone stock 2000 Civic SI as my daily commuter car (sorry but at least it's a *little* sporty). The WRX gets driven a few times a month when I want to pull some g's and tick off a few of the local rednecks in their Mustangs, Camaros, etc. Of the 10K miles I've put on, more than 3000 of them have been at the track. I've come to think of the car as my 'track car', which is occaisionally driven on the street. A little history on my setup is in order. Going back about a year ago, I installed Prodrive springs on the stock struts. It looked great and handled better than stock. For street driving and curb appeal, they were just what I was looking for. But, after 12 months and ten (10) track days on this setup, I'm convinced that the stock struts are underdamped. I'm sure this is not a big surprise to anyone, but I wanted to really evaluate the combination for a while before making any changes. In short, the Prodrives are better than the stock springs, but the stock strut just can't control the spring motion all that well. I evaluated and discarded many coilover solutions. All of them seemed to have a major issue: too expensive, too noisy, too bouncy, etc. Since I don't have a set of scales (yet), I also didn't want the hassle of re-corner weighting the car every time I made an adjustment to my coilover setup. (The conventional wisdom says that a non-corner weighted car with coilovers will not reach its full handling potential and may, in fact, be total crap.) I just couldn't convince myself that they were the way to go due to all the compromises they introduce. Remember, I'm old! After a recent track day, one of the instructors came up to me and said that he liked my line, but that the back end of the car was very "sloppy...nervous, and twitchy". He was behind me in another car, which gave him an opportunity to see it firsthand for a number of laps. Here's where the fun begins...he told me that his student the month before at Sebring had put the Koni inserts on his WRX and the handling of the car was "transformed" from the stock struts. How could I resist that? I went home, hit NASIOC, scoured the Internet, and found nothing on the topic. I agonized over it for all of about 30 seconds or so before I just said screw it -- I'm going for it. I don't care if anybody else has done it or not, it's something I want to do. So I quickly located a vendor selling the inserts and bought them (for cheap, I might add). Since I knew I would have to take the struts apart again, I figured I might as well buy a set of camber plates for the front. After some research, I settled on the Cusco camber-only plates from Gruppe-S. I wanted to dial up some negative camber in the fronts for use at the track, but get a repeatable street alignment for the other times. I didn't want to do the rear plates because they would basically need to be removed from the car to make adjustments (I drive a sedan). For wagon owners, this may be something you want to do since it's much easier to get to the top mount. I hooked up with my suspension guru buddy here in Atlanta and we scheduled the install. We reviewed PaulTG's excellent set of pictorial instructions (do a search) and went to work. The installation was not a problem, taking maybe an hour for the first one and about 45 minutes for the other three; this is from unbolting the lugnuts to putting them back on. Maybe some of you can do it quicker but I like to be meticulous. Remember, I'm old. Once that was done, the car went up on the alignment rack. I wanted two things out of this: a 'max negative camber' setting for the track, and a 'save the expensive 18" rubber for the street' setting. Here's how it came out; measurements are in degrees: Street alignment: Camber, LF -0.7, RF -0.9 Toe, LF 0.07, RF 0.03 Camber LR -1.2, RR -1.7 Toe, LR -0.08, RR -.04 Max negative camber alignment: Camber, LF -2.6, RF -2.6 Toe, LF -0.70, RF -0.72 (rears are kept the same) The Cusco camber plates have a series of hash marks on top. Each of the hash marks represents .2 degrees of change in the alignment. We scribed the plates to mark the zero point for the street alignment so it can be put back in the same place after a track day. The max negative is just slam the strut top all the way in... Now for the driving impressions. I have not had a chance to test every combination yet, but I'm working on it. It's hard to find roads to wring the suspension out on when cars aren't coming in the opposite direction. I'll update the thread after the next track day... Here's my total suspension setup: Whiteline adj. rear sway, 'race' version 22-24-26mm effective diameter, currently set to 22 (remember, I'm old. ) Prodrive springs all around Koni inserts all around Cusco camber plates in front Vivid prototype alloy rear sway endlinks (like Kartboy) Street tires: Michelin Pilot Sports, 225/40/18 on Rota Subzeros Track tires: Kumho Victoracer V700, 225/50/16 on stock rims Tire pressures vary depending on what I'm doing (sorry) My first drive was on the track tires, left on there from this last track day. The Konis were set to full soft (all the way counterclockwise), and I was using the 'street' alignment. The ride on normal Atlanta roads could be described as firm but definitely compliant. The additional damping provided by the Konis kept the tires planted even on small bumps and imperfections. Yummy! If I had to put a number to it, I would say that the Konis at full soft are maybe 10-15 percent more rebound than stock. However, it was never a harsh ride or anything unusual. I actually thought in my mind that it was very similar to a stock BMW E36 M3. You know you're very much in control of the car and that it's not going to let you down. I didn't always have this feeling on the stock struts. It was a little too 'floaty' for my tastes. After 20 minutes, I got home and grabbed my 9 year old son (car guy in the making). I let him run the tools while I did the heavy lifting and QC to throw the street tires back on. I also took the opportunity to show him the new suspension. Leaving the Konis set to full soft, I took off and beat around a few of the local twisties. As you might expect, the ride from the shorter sidewalls on the 18's was a bit more harsh on the leading edges of bumps and cracks, but the extra damping was still there on the trailing edges. Overall, even though I had less grip than the track tires I immediately had that same sense of confidence in the suspension that had been missing before. I had enough grip to take 25 mph corners at 60 with no problems. Lovely! I got home and set all the Konis one-half turn towards hard. Koni says that one full turn is full hard, so I thought I'd test it in the middle. The increased rebound stiffness was immediately apparent. The ride quality was definitely more towards the 'sporty' side. I could now feel every pebble and crack in the roadway, and not just the front side either! I could actually feel the tires coming down off the back side of a crack or expansion joint. The inserts were doing their job and doing it well. The car was not bouncy at all. Over ripples, the car would give one compression of the springs and then BAM, level it right out. To be honest, if you are the kind of person who likes the ride of a Buick or Cadillac, you would probably think this was too firm and annoying. For myself, I thought it was great. It was almost like driving a completely different handling car. In medium speed sweepers (like an off ramp), I was totally blazing on the street tires. Both ends of the car were just so much more planted than ever before. I took a 35 mph off ramp at 75 with hardly a squeal from the Pilot Sports. Not that I'm suggesting you try this of course. Everyone needs to observe proper street driving technique and of course obey all traffic safety laws. On the way home, I tried a 90 degree right hander that I'm really familiar with. Wow, this car is amazing! In my Honda, I plow like a pig. In the WRX before the Konis, I plow a little bit then the tail kicks out as I get a little wheelspin and loosen it. With the Konis, I got no understeer at all, a nice controllable little rear end slide of about 6-8 inches, then BOOM, off like a rocket from the apex. In tight corners, the Konis really keep the tires on the ground, especially the insides where the factory struts would just give up. It's like I have an extra 25 horsepower under the hood now...killer! I came in from work and the wife said 'What are you so happy about? Why do you have that big cheshire cat grin on your face?' I explained and I think she might have even understood why. So that's the end of my little (heh) story for now. I have several more things to try: full hard with the streets, medium and full hard with the Victoracers, then the camber plates set to max negative for all of them. I'll update as I get to these setups. If you're on the fence about doing this, just do it. Sorry for the length, but I just wanted to get it out there for everyone in case you are interested. I'm (obviously) not a suspension expert, engineer, or race car driver. I'm just an average person with a real love for cars. Thanks again to Alex Peformance for the killer deal on the Konis, Gruppe-S for the killer deal on the camber plates, my good buddy SteveD here on NASIOC for the install assistance, and of course GTguy, PaulTG, and everybody else who have taught me so much about how to make a Scooby handle. I appreciate it all! Feel free to ask questions or whatever. I think it would be cool if we could make this one of those reference threads that people will be looking back at for the next year or two. We can make the path much easier for the folks who follow us. Later! Scott
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Last edited by sdecker; 04-18-2003 at 04:49 PM. |
04-17-2003, 03:55 PM | #2 |
Got the F out
Moderator Member#: 4797
Join Date: Mar 2001
Chapter/Region:
MWSOC
Location: central ohio
Vehicle:05 05, 01, 98, 95 CGM |
Wow! Someday I'll make it through the whole post!
I've got an eerily similar setup: Koni SA's (full soft all around street, AutoX is typically full stiff rear and slight 1/4-1/2 turn front depending on grip of surface) Cusco front plates, OEM rear tophats MRT 30mm springs (similar to Prodrive rates) Whiteline 20-22-24 bar set to 24mm Kartboy droplinks Rota SubZ's 17x7.5 Falken Azenis 225/45-17 add: Whiteline front and rear strut braces I'm an AutoX junkie so that where I spend most of my time. I have 1 track day under my belt, but don't see any in the near future due to $$$. I LOVE this setup for just about everything, except getting a jack under the car!!! My alignment is slightly whacked up front now since I had an off track excursion last fall at Texas World Speedway, but that's easily taken care of. At the track day, my instructor was very pleased with the setup. He made mention that it really shined over the other Subies he had driven at past events, including some with coilovers. I've been on this setup since right before the Solo II Nationals last year so it's been ~7500 miles of daily driving, 200 miles at the track, and ~7 AutoXs. My only big complaint is that I had to use the car a lot this winter since our other daily is a Z28. Now I need to clean everything up to limit corrosion. |
04-17-2003, 04:37 PM | #3 |
Scooby Specialist
Member#: 14717
Join Date: Jan 2002
Chapter/Region:
South East
Location: Road Atlanta
Vehicle:2002 WRX, WR Blue Complete n00b Racing |
Heh! Sorry about the length but I figured I'd try and get it all out there up front...so I don't get the 47 million questions later, if you know what I mean. Oh wait, you're a mod, you DEFINITELY know what I mean.
Questions aren't a problem people...ask away. I'm just a little long winded today. Orion, doesn't this setup work *great*? I am just blown away by it. Even with the stock struts I can hand it to the Bimmers on the track...I can't wait until I get out there again. Take the time to review the REALLY LONG thread and let me know if you see anything glaring that I should address. These reference threads are too few and far between... Scott |
04-17-2003, 05:24 PM | #4 |
Got the F out
Moderator Member#: 4797
Join Date: Mar 2001
Chapter/Region:
MWSOC
Location: central ohio
Vehicle:05 05, 01, 98, 95 CGM |
I've driven on a few different setups. Mostly Sti suspended wagons and a stock sedan with just Koni's and some Kumho's at an AutoX.
I'm hoping to get to drive a friends wickedly modded car with JIC FLT-A2's with horrendously stiff rates soon. I gotta say that the STi kits on wagons were ever so slightly more livable for daily driving, but there's no ability to adjust to the conditions. I'll take the adjustablility over a little ride comfort anyday. I will say that the comfort level in my car is greatly affected by the wheel/tire combo. When I have the OEM wheels on with the BFG KDW 215/50-16 the ride is not as nice as the 17" Rotas with Azenis. The little 215/50's tend to get bouncy over rough stuff. I'll be going back to the OEM size 205/55-16's later this year since the KDW's wont last through the year and into winter. |
04-17-2003, 06:40 PM | #5 |
Scooby Specialist
Member#: 9407
Join Date: Aug 2001
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Location: Middle TN
Vehicle:02 WRX platinum silver |
have you thought about going to stiffer springs, like a GroundControl set-up or do you think the Prodrive springs work well with the inserts?
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04-17-2003, 06:41 PM | #6 |
Scooby Specialist
Member#: 12901
Join Date: Dec 2001
Chapter/Region:
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Location: Miami Springs, FL
Vehicle:2005 STi/95 VX Pastelito Racing / SFSOC |
Scott,
Thank you for such a informative post about your experience with your car setup. Posts like that are what keeps me coming back to NASIOC for information and news on my WRX. Being someone that auto-x's consistently in DS solo 2 I have been considering the Koni inserts for my WRX also. Since I am greatly limited in my options for stock class, thankfully koni's are aloud, these would give me a great boost in handling. My question is in regards to the rear shock adjustments. How is this done. I can see how the front will be easy to adjust, but how do you go about adjusting the rear? Thanks, K |
04-17-2003, 06:45 PM | #7 |
Scooby Specialist
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Join Date: Aug 2001
Chapter/Region:
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Location: Middle TN
Vehicle:02 WRX platinum silver |
you would have to pull the rear seat to get to the top of the strut. might want to try and hold out for the KYB's if they would ever release them.
p.s. I agree, this was a great write-up. |
04-17-2003, 06:50 PM | #8 | |
Scooby Specialist
Member#: 14717
Join Date: Jan 2002
Chapter/Region:
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Location: Road Atlanta
Vehicle:2002 WRX, WR Blue Complete n00b Racing |
Quote:
Scott |
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04-17-2003, 06:53 PM | #9 | |
Scooby Specialist
Member#: 14717
Join Date: Jan 2002
Chapter/Region:
South East
Location: Road Atlanta
Vehicle:2002 WRX, WR Blue Complete n00b Racing |
Quote:
Scott |
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04-17-2003, 06:54 PM | #10 | |
Scooby Specialist
Member#: 12901
Join Date: Dec 2001
Chapter/Region:
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Location: Miami Springs, FL
Vehicle:2005 STi/95 VX Pastelito Racing / SFSOC |
Quote:
K |
|
04-17-2003, 06:55 PM | #11 | |
Scooby Specialist
Member#: 14717
Join Date: Jan 2002
Chapter/Region:
South East
Location: Road Atlanta
Vehicle:2002 WRX, WR Blue Complete n00b Racing |
Quote:
and thanks for the compliment. I figured I ought to give something back to the community, being as how I've used enough of everybody else's information in the past. It's what NASIOC (the *original* I-club) is all about. Scott |
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04-17-2003, 06:59 PM | #12 | ||
Scooby Specialist
Member#: 12901
Join Date: Dec 2001
Chapter/Region:
South East
Location: Miami Springs, FL
Vehicle:2005 STi/95 VX Pastelito Racing / SFSOC |
Quote:
Quote:
K |
||
04-17-2003, 07:02 PM | #13 | |
Got the F out
Moderator Member#: 4797
Join Date: Mar 2001
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Location: central ohio
Vehicle:05 05, 01, 98, 95 CGM |
Quote:
edit: oops! i didn't read all the responses! |
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04-17-2003, 07:02 PM | #14 | |
Scooby Specialist
Member#: 9407
Join Date: Aug 2001
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Location: Middle TN
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Quote:
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04-17-2003, 07:04 PM | #15 | |
Got the F out
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Join Date: Mar 2001
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Quote:
also, if the inserts are full stiff, the springs are overmatched. a stiffer rate would make these struts shine IMO. |
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04-17-2003, 07:08 PM | #16 | |
Got the F out
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04-17-2003, 07:47 PM | #17 | ||
Scooby Specialist
Member#: 14717
Join Date: Jan 2002
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Quote:
Quote:
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04-17-2003, 07:55 PM | #18 |
Got the F out
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nah, we're just old farts that can't stand outrageous spring rates. our frail backs would break leaving the driveway!!!
i think anything over what we mentioned would be too much for the koni's at anything but full stiff all the time. i've left the car adjusted for the track a few times and it ain't pretty on the freeway!!! PS - MidOhio ownz Road Atlanta!!! |
04-17-2003, 10:25 PM | #19 |
Scooby Specialist
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Join Date: Jan 2002
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My kidneys hurt just thinking about it! I think my dentures are rattling loose, too! Seriously tho, I'd surely love to drive Mid-Ohio one day...I think the WRX makes a pretty damn good track car IMHO. It's a little heavy but I r0x0r all over M3's and even mild race prepped cars even with the stock struts. I am so stoked to get out there again and do some ass-handing! Let's keep the thread alive, maybe some other folks will check in. Scott |
04-18-2003, 12:27 AM | #20 |
Scooby Specialist
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Join Date: Jan 2002
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Orion:
Have you played around with different adjustments front to rear on your Konis? I'd be interested in your observations that lead you to 1/4 to 1/2 turn in front and full stiff in the rear...wait, that didn't sound right. |
04-18-2003, 12:52 AM | #21 |
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Sounds like an awesome setup!
From all I've learned, I think that this is pretty much what I would do to my car also if I wasn't getting into another race car (so pretty much no money for WRX mods). I really would love to check it out one of these days. |
04-18-2003, 01:01 AM | #22 | |
Got the F out
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Quote:
OK, that wasn't very scientific, and it may be total BS, but I think that's the outcome of my settings. I just spent 2 days tuning the car in my new region on a surface I had never run on before and it appears I have some more work to do. I'll report back here after the next event (4/27) with a full update. |
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04-18-2003, 02:02 AM | #23 |
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Vehicle:2002 WRX Wgn 292whp Alex Performance |
Hi Scott. I'm glad your setup worked out for you. I'm still waiting to finish my car Working 14-16 hour day and a girlfiriend leave you very littl time Hopefully next weekend I'll get to enjoy it. It will be interesting to see how linear springs compare to progressive with Koni's. I have Koni's with linear springs on my race car and I have Whiteline progressive springs on my WRX and I'll use those with Koni's. How are those camger plates on the street? Noisy? I really want a set but I drive on the streets of NYC and everybody knows how bad those are.
I'll keep an eye for your post when you get to take your car to the track. Take care, Alex... Alex Performance |
04-18-2003, 02:32 AM | #24 |
Got the F out
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the cusco plates do clunk quite a bit. columbus doesn't have particularly great roads either so i definitely hear it more than when i lived in houston.
linear springs and progressive springs at lower rates (20-30% greater than stock) should make no difference. the real difference would noticable at much higher rates. |
04-18-2003, 10:11 AM | #25 |
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Great write up.
BEFORE you go putting on the higher rate springs, you may want to check with Koni to make sure they will be able to handle the spring, or you may end up with a bouncy ride looking like you're riding on cut springs. Something about rebound not being able to match the speed of the spring when it un-compresses. Not sure but I think that's it. Most struts can only handle a range of springs weights without the need for custom valving. If you're running on inserts made for 'just above stock' performance, you may find that the most they can handle is ~300-400 lbs at the top of the spectrum. I'm currently looking for a setup that'll handle much more than the stock spring rates.... and it's proving to be quite the challenge to find a strut that will offer the proper damping/rebound for the springs. --kC |
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