Koni Yellow / GC Coilover Review (long)
09-03-2015, 08:18 AM
#1
Koni Yellow / GC Coilover Review (long)
As some of you know I have been through an exhaustive search for coil over replacement options for my street/track S2k. I finally decided to pull the trigger on the Koni/GC coilovers for my car. The stock 00' oem shocks with H&R lowering springs came off and these went on. My goals were to: have some ride height adjustment (preload), go from under damping to critically damping with stiffer springs, restore some of the OEM neutrality that was lost with the lowering springs. I run stock AP2 sized BFG rivals and track intermediate and street drive the car.
I ordered the full GC kit including 500/500 (9K) springs and their tophats. I went with even spring rates because I knew I would be staggered for a while. Also 500lbs seemed like a good balance between the max the shocks could handle and not being too soft for track work. The rest of the suspension is stock.
Installation was straight forward, but the first issue was revealed. At static ride height, there was virtually no bump travel before hitting the stop in the rear. This manifested in a springiness in the rear that made it bouncy over elevation changes. There were two solutions to this issue. One, cut the bump stop and two modify the dust cap on the shock so it could actually go into the upper mount. This increased the effective travel. Without modifying the cap I question the value of the GC top hat as the shock body would bottom on the lower most portion of the mount. As delivered I would guess the GC top hats actually reduce effective travel as compared to the stock top hats. After the dust cap modification I would guess there is slightly more available travel then with the stock top hat. But this is a guess, and in both situations you should be well into the bump stop at this point. After this was done I had about 1 3/4" of clear piston at static ride height. As comparison I had about 2" in the front.
My initial settings for road testing were ride height at 13.5" rear, 13.25" front and .5 turns out from full soft front and rear. Konis have about 2 full turns of adjustment so these settings are about 25% of full stiff. Overall it had a stiff but decent ride, good response but still had the residual suspension oscillations as before (bounciness). On GC recommendation I jumped to 1.25 turns in the front and 1 turn in the rear. This definitely tightened the car up and made it feel more glued to the road. I did notice when going over recessed manholes, the car started to fall into these more. So the body moved around more as it followed the road surface, but it also felt stuck to or was being pulled into the road. Overall a positive, but took some getting used to.
Adjustment wise, there is no cross talk as the compression damping is constant while the rebound can be increased significantly. With the rebound turned up the compression damping is less, relatively. I wonder if this contributes to the feeling noted above. Also a softer spring may be able to be utilized if the upward stroke was slowed some. If there is any complaint with the Koni valving, this is it. However this is a nuanced point and I am no expert. Overall the handling and feel were great.
I was able to run this setup on one track day. Overall results were very good. The car was neutral but when pushed very hard under power would go into ever so slight oversteer. There was tons of front grip and the car felt composed. Overall it felt like there was more grip than I was willing, or had the ability to use. It took some time to adjust to the firmer setup, but as the day went on I developed confidence in what the car was able to do. My only complaint was on one part of the track there was a rougher transition that seemed to have the shocks struggling to control the body without using some extra cycles.
I took a long street drive the following weekend and the longer I drove it the more I noticed when the suspension was impacted hard, the recovery took slightly more than one cycle. I stopped off and decided to go .25 turns stiffer on all shocks (1.5 turns/75% front, 1.25 turns 62.5% rear). I noticed an immediate improvement in damping control. Now its one compression stroke, one rebound stroke, and done. I am not sure exactly what critically damping feels like but I am guessing this is close. There was the trade off of a noticeably stiffer ride, to the point I would say its close to the limit of a street car (for me). However its still compliant over mild and moderate road imperfections.
Now it has excellent body control, response, sharpness, predictability, etc. Overall it feels like the suspension can do no wrong, its stiff but it is never upset or losses grip going over rough roads. You have the confidence to know you can load up the tires laterally, hit a rough patch and know the suspension will sort it out. The body does move around more as it sticks to the road, but it never losses grip. The ride is stiff but not painfully so. Overall the ride is somewhat stiffer than stock, but compliant and responsive.
Pros:
Price/Value
Plenty of damping to control stiffer springs
Preload adjustability
Functional damping adjustment
Great handling ride balance
Cons:
Have to deal with limited rear travel
Question value of GC top hats compared to OEM
Better damping balance (More compression / less spring rate) might yield similar performance without as stiff as ride. (just a guess)
Verdict:
If you have similar goals to mine, for the price you can't beat this setup.
I ordered the full GC kit including 500/500 (9K) springs and their tophats. I went with even spring rates because I knew I would be staggered for a while. Also 500lbs seemed like a good balance between the max the shocks could handle and not being too soft for track work. The rest of the suspension is stock.
Installation was straight forward, but the first issue was revealed. At static ride height, there was virtually no bump travel before hitting the stop in the rear. This manifested in a springiness in the rear that made it bouncy over elevation changes. There were two solutions to this issue. One, cut the bump stop and two modify the dust cap on the shock so it could actually go into the upper mount. This increased the effective travel. Without modifying the cap I question the value of the GC top hat as the shock body would bottom on the lower most portion of the mount. As delivered I would guess the GC top hats actually reduce effective travel as compared to the stock top hats. After the dust cap modification I would guess there is slightly more available travel then with the stock top hat. But this is a guess, and in both situations you should be well into the bump stop at this point. After this was done I had about 1 3/4" of clear piston at static ride height. As comparison I had about 2" in the front.
My initial settings for road testing were ride height at 13.5" rear, 13.25" front and .5 turns out from full soft front and rear. Konis have about 2 full turns of adjustment so these settings are about 25% of full stiff. Overall it had a stiff but decent ride, good response but still had the residual suspension oscillations as before (bounciness). On GC recommendation I jumped to 1.25 turns in the front and 1 turn in the rear. This definitely tightened the car up and made it feel more glued to the road. I did notice when going over recessed manholes, the car started to fall into these more. So the body moved around more as it followed the road surface, but it also felt stuck to or was being pulled into the road. Overall a positive, but took some getting used to.
Adjustment wise, there is no cross talk as the compression damping is constant while the rebound can be increased significantly. With the rebound turned up the compression damping is less, relatively. I wonder if this contributes to the feeling noted above. Also a softer spring may be able to be utilized if the upward stroke was slowed some. If there is any complaint with the Koni valving, this is it. However this is a nuanced point and I am no expert. Overall the handling and feel were great.
I was able to run this setup on one track day. Overall results were very good. The car was neutral but when pushed very hard under power would go into ever so slight oversteer. There was tons of front grip and the car felt composed. Overall it felt like there was more grip than I was willing, or had the ability to use. It took some time to adjust to the firmer setup, but as the day went on I developed confidence in what the car was able to do. My only complaint was on one part of the track there was a rougher transition that seemed to have the shocks struggling to control the body without using some extra cycles.
I took a long street drive the following weekend and the longer I drove it the more I noticed when the suspension was impacted hard, the recovery took slightly more than one cycle. I stopped off and decided to go .25 turns stiffer on all shocks (1.5 turns/75% front, 1.25 turns 62.5% rear). I noticed an immediate improvement in damping control. Now its one compression stroke, one rebound stroke, and done. I am not sure exactly what critically damping feels like but I am guessing this is close. There was the trade off of a noticeably stiffer ride, to the point I would say its close to the limit of a street car (for me). However its still compliant over mild and moderate road imperfections.
Now it has excellent body control, response, sharpness, predictability, etc. Overall it feels like the suspension can do no wrong, its stiff but it is never upset or losses grip going over rough roads. You have the confidence to know you can load up the tires laterally, hit a rough patch and know the suspension will sort it out. The body does move around more as it sticks to the road, but it never losses grip. The ride is stiff but not painfully so. Overall the ride is somewhat stiffer than stock, but compliant and responsive.
Pros:
Price/Value
Plenty of damping to control stiffer springs
Preload adjustability
Functional damping adjustment
Great handling ride balance
Cons:
Have to deal with limited rear travel
Question value of GC top hats compared to OEM
Better damping balance (More compression / less spring rate) might yield similar performance without as stiff as ride. (just a guess)
Verdict:
If you have similar goals to mine, for the price you can't beat this setup.
09-03-2015, 09:57 AM
#2
Former Sponsor
Good review! I loved this setup on my S2000. Had it for 5-6 years. Can't beat it for the money! I always recommend this setup for the 1k price range. Most go with the cheapo Megan, D2, etc coilovers. These ride and perform so much better!
09-03-2015, 12:11 PM
#5
I looked at the FAs very closely. I preferred the mono tube design. The only reason I went with Koni and Eibach is because they are more of a known item. Maybe they would be easier to sell if need be?? Also I found a few negative reviews on the early FA stuff. These were old though, and like I said I was very close to trying FA shocks.
09-03-2015, 12:15 PM
#6
Notice in this picture the dust cap is not wider on the top. I ground that area to make the walls smooth. The blue marker line indicates how far the cap goes up into the mount before bottoming. FYI, at that point the shock body is hitting the upper mount at almost the same time the shock piston is bottoming internally. So really there is nothing left.
09-03-2015, 01:42 PM
#7
Originally Posted by uh0h50' timestamp='1441306262' post='23736148
Nice review. Can you show/explain exactly how you modified the dust caps?
Notice in this picture the dust cap is not wider on the top. I ground that area to make the walls smooth. The blue marker line indicates how far the cap goes up into the mount before bottoming. FYI, at that point the shock body is hitting the upper mount at almost the same time the shock piston is bottoming internally. So really there is nothing left.
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09-04-2015, 04:41 AM
#9
I would love to just be able to try coilover after coilover. I don't want to let very good be the enemy of perfect, if perfect even exists. However, here is what I would try if I had more money and time.
FA500 with 9K/9K springs and 11K/11K damping
KW V3 off the shelf
Ohlins DFV off the shelf
But.... My Koni setup now is better than what I had and gave me everything I asked for. For the money its a winner. I cant wait to take it to the track with the latest damping adjustment.
FA500 with 9K/9K springs and 11K/11K damping
KW V3 off the shelf
Ohlins DFV off the shelf
But.... My Koni setup now is better than what I had and gave me everything I asked for. For the money its a winner. I cant wait to take it to the track with the latest damping adjustment.
09-04-2015, 06:39 AM
#10
Moderator
I would love to just be able to try coilover after coilover. I don't want to let very good be the enemy of perfect, if perfect even exists. However, here is what I would try if I had more money and time.
FA500 with 9K/9K springs and 11K/11K damping
KW V3 off the shelf
Ohlins DFV off the shelf
But.... My Koni setup now is better than what I had and gave me everything I asked for. For the money its a winner. I cant wait to take it to the track with the latest damping adjustment.
FA500 with 9K/9K springs and 11K/11K damping
KW V3 off the shelf
Ohlins DFV off the shelf
But.... My Koni setup now is better than what I had and gave me everything I asked for. For the money its a winner. I cant wait to take it to the track with the latest damping adjustment.
I had both the KW v3 and now have the Ohlins. The DFVs make the KWs feel like cut coils and blown shocks. They are worth every penny.