STi RA Springs/Koni Strut Insert initial review. - Page 2
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This is a discussion on STi RA Springs/Koni Strut Insert initial review. within the Suspension & Wheels forums, part of the Tech & Modifying & General Repairs category; No, he's speaking of a "pink and black" setup. Adjustable struts combined with standard v7 STi springs. Chris...

  1. #16
    Moderator GV27's Avatar
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    No, he's speaking of a "pink and black" setup. Adjustable struts combined with standard v7 STi springs.

    Chris
    "Inasmuch as ye have done it to one of the least of these my brethren, ye have done it to me." -Jesus

    1990 Alfa Romeo Spider Veloce
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  3. #17
    Moderating on the run! Big Sky WRX's Avatar
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    Originally posted by GV27
    No, he's speaking of a "pink and black" setup. Adjustable struts combined with standard v7 STi springs.

    Chris
    Correct- rates ~ 188/173, oe height

  4. #18
    Moderator GV27's Avatar
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    Originally posted by vano
    Are the bump/rebound rates of the Konis much more different that the STi shocks?
    Forgot to mention that the rebound rates on the Konis are adjustable. From what Koni says, they have a very wide range of adjustment that should cover the entire range of the STi adjustables and then some. But with the STi adjustables you adjust bump and rebound at the same time. Which is a double edged sword. On one hand its great to have both adjustments, but on the other, the effective spring rate goes up when you adjust them stiffer.

    So if you take a Koni strut, and successively use, say, stock springs, standard STi, STi Lowering and STi RA springs you can adjust the rebound to suit each spring, and the effective bump rate only goes up according to how stiff the spring goes.

    With the STis, if you increase rebound damping, you also increase compression damping so the effective bump rate goes up more than the rate increase of the spring.

    But then the STis have a smaller range of rebound damping and are designed to work with a narrower range of spring rates. The Konis by neccesity have to be designed for a large range of springs from stock to super-stiff since Koni doesn't know what spring you might be running with them since they don't make the springs.

    Does that make any sense? Basically what I'm trying to say is that if you increase the spring rate used with any one particular bump damping setting (say you put aftermarket springs over stock struts) the harshness should increase in proportion to the spring rate. But if you add compression damping, the harshness should increase even more, all else being equal.

    But of course all else is not equal as strut makers can tune the curve of the damping rates compared with the rate of suspension travel, which makes things complicated. So we have the numbers for the STi struts at one particular travel rate for the STi struts in the STi trivia thread. But even if we knew that the Konis were, say, equal at that travel rate, that still doesn't tell the whole story as the curves might be different.

    This is a failing of the '02 - '03 stock struts as they use very simple valving resulting in a less than ideal curve. This has supposedly been remidied for '04.

    So it's a complicated equation we're talking about and as Big Sky says, full of compromises.

    I need to do a rebuild on my CBR600 forks and I plan to do a piece on multi-level damping using the aftermarket valve cartridge I have installed in them as an example. Stay tuned.

    Chris
    Last edited by GV27; 05-02-2003 at 09:18 AM.
    "Inasmuch as ye have done it to one of the least of these my brethren, ye have done it to me." -Jesus

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  5. #19
    Moderator GV27's Avatar
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    :D Gravel Report

    I was reading and commenting on this thread this A.M. and realized I hadn't taken the car for a gravel test on the new suspension yet. I had tested on some very rough pavement but not the dirt. I used this as an excuse to get my little boy (he'll be 2 next month) up to the mountains and do a little gold prospecting. Unfortunately I didn't find any, but I only did about 5 pans full and didn't bother with my sluice box - that's hard to do while keeping an eye on a 2 year old who could get swept downstream! He had a great time but cried bitterly when we left.

    Anyway, the setup is even better on the dirt than I expected! Incredibly smooth. The road I hit stays fairly well graded as it passes through a rather posh mountain subdivision on one end, yet there is always plenty of washboard due to a bunch of very slow (1st gear) switchbacks. The car is now the best car I've ever driven on washboard - even better than stock, which is one place where the stock suspension really excelled. The car still has snow tires on - my ES100's just showed up today. The handling is great on the dirt, very easy to rotate and now it is possible to charge into a corner and "back it in" scrubbing speed all the way to the apex. Where it REALLY excelled were over the cattle grates on either end of the road. These were quite jarring with the stock suspension but the new setup floated right over them, with just the vibration of the grate being felt. Sweet! I couldn't be happier.

    Probably the best testiment to the ride quality is the reaction of my little guy. I was kinda wondering about him, as normally I'll hear mad giggling when driving like that - he just loves it. But it was getting towards nap time. At the end of the road I was finally able to look back at him, expecting to be met by a big grin. Instead he was asleep!!

    Chris
    Last edited by GV27; 05-02-2003 at 11:52 AM.
    "Inasmuch as ye have done it to one of the least of these my brethren, ye have done it to me." -Jesus

    1990 Alfa Romeo Spider Veloce
    1992 Toyota 4Runner SR5 3.Slow
    1993 Honda CBR600F2
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  6. #20
    Moderating on the run! Big Sky WRX's Avatar
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    Great story! Isn't amazing after all the technical talk sometimnes it can come down to a very simple "test"- your son in this example.

    I remember when I first got my reflashed ecu- I did a bunch of datalogging, road dynos and other assorted testings. I didn't say anything to my wife (it's her daily driver), the next day day she says what the hell did you do to the car (I'm thinking ohh-oh, the dam thing doesn't drive worth a dam around town). So I coyly asked why and she said this car flys! Tests validated.

    Back on topic, I didn't realize Konis were rebound adjustable only- learn something new every day. Good point on the double edged sword of controlling both bump/rebound w/ a single adjustment. The one saving grace w/ the STi struts (oe or adjustable) is that they are "designed" w/ any of the three springs mentioned (sti, sti sport, RA)- get out of these ranges and it's anybody's guess. Although I have heard positive results from a few people using the oe (STi) struts w/ the Prodrive springs- my guess is, w/ the exception of the lowering) the rates are close to the std STi- although they are also highly progressive, much more so than any of the STi bits.

    Big Sky

    edited by GV27 for brand accuracy - though I believe that the KYBs are also rebound adjustable only.
    Last edited by GV27; 05-02-2003 at 03:17 PM.

  7. #21
    Moderator GV27's Avatar
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    The other "saving grace" with controlling both bump and rebound is that you can taylor the ride more w/ bump adjustment. I'm sure STi thought of this when they designed the bump/rebound profiles that go together at each setting. But again, that's gonna make it more sensitive to the spring used. So w/ the proper springs its almost certainly a superior way of doing things. Of course double-adjustable is really what you want if you have the cash AND the expertise to properly set them up (the part most people who buy high-end coilovers lack).

    At first I was bummed when I figured out the Konis were only rebound adjustable (figured it out from Godspeed Dan's dizzying suspension write-up, then confirmed by closely reading the answers from Koni I posted in the Koni Info thread) but then figured out that I love the ride and I can control it a bit through the rebound adjusting plus can control the "balance" quite effectively that way.

    Chris
    "Inasmuch as ye have done it to one of the least of these my brethren, ye have done it to me." -Jesus

    1990 Alfa Romeo Spider Veloce
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  8. #22
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    Talking Thanks for the review....

    Very informative and inspiring. I just had Prodrive springs installed and NOW i have the cash to consider this option too. I wish i could have done it at the same time. Maybe i will go for it and have it done at the same time with my Noltec Camber plates from Mike's group buy.

    Thanks again GV27. Now get on out here so you can teach Mike and I a lesson on one of our AutoX courses.

    Rick.
    No cones.

  9. #23
    Moderator GV27's Avatar
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    Just revisiting this thread since I had a guy PM me about the Konis.

    The handling is quite excellent w/ my Yokoham ES100s. Not as much grip out of the tires as I would have hoped (a tire issue not a suspension issue - they're just not as grippy as the Dunlop SP8000s I used to have) but the balance is MUCH better and very confidence inspiring. The chassis is way taughter and much easier to adjust mid-turn than before. No more wallowing sensation, no more fear of terminal understeer.

    There was a bunch of talk about harshness earlier in the thread. There is a difference between harshness and stiffness. To me, harshness is where small bumps jar you as you go over them - like manhole covers, washboard on dirt roads, etc. Stiffness is the big stuff - like maybe where there is a big dip on the backside of a large road patch or something like that. With these definitions my setup is much LESS harsh than stock but much stiffer as well. So small imperfections in the road like manhole covers, washboards, minor potholes, etc are soaked up much better and smoother that stock. On the other hand it is much stiffer.

    A good example is a virtually abandoned frontage road near my house. I'm usually going quite fast - at least 70, usually more like 80 or 90 -and there is a spot where I guess the road was sinking at one time. There is a big asphalt patch where they built up the road. The entire width of the road, maybe 20 feet long (longer than the wheelbase of the car but not by a lot, but again I'm going fast when I hit it). So there is a bit of a rise at the front, a drop-off at the back and then the road rises back up - like the road was sinking and they didn't quite make the build up long enough so it's sorta like: /--------\__/-------------. But the bumps themselves are quite gentle - the whole thing is at least 40 or 50 feet long. Probably more.

    With the stock suspension the car would sorta float over it, then bounce gently on the other side. You didn't really feel like you were going up and down a lot. With my setup, you definitely feel it a lot more. You definitely go up, then down and back up. The good thing though is that you have a lot of control. With the stock setup you kinda floated along for the ride. You'd have to wait for it to settle down if you needed to maneuver on the other side. With my setup, you feel it a lot more, but if you had to you could manuever right after the undulations - in fact you could maneuver over the top of the patch. With the stock setup you're just floating over that. The car would just skate if you tried to manuever.

    Chris
    "Inasmuch as ye have done it to one of the least of these my brethren, ye have done it to me." -Jesus

    1990 Alfa Romeo Spider Veloce
    1992 Toyota 4Runner SR5 3.Slow
    1993 Honda CBR600F2
    2002 WRX SportWagon *sold*

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