Koni yellow shocks and appropriate spring rates

[snowborder714]

I've been talking via PM to jtoby for a while on this, so I'd like to put some of this info out in the open for other people to benefit from. I've also got some questions for jtoby (or anyone else with Koni yellow and autox/road racing experience) that I'd like to address.

First off, I've read/been told that Koni yellows can handle roughly 600-800lb springs up front before revalving needs to be considered. The rears seem good for 300-400lb springs. If any of this is wrong, please correct me.

jtoby mentioned today in a PM that he would feel that off the shelf (OTS) Koni yellows could handle, say, and 850/375 combo for autox because you're only pushing them hard for about 60-90 seconds and then they get a good bit of time to cool down. However, he said he wouldn't recommend this for a road race setup, since you're pushing them hard for 20 minutes at a time.


So, my questions:

1. What spring combo would you recommend as a max for an autox only setup on OTS Koni yellows?

2. What spring combo would you recommend as a max for an road race only setup on OTS Koni yellows?

3. What would happen to the shocks if I tried to run high spring rates (my current setup is 700/400 and I'm building it to be a road race car)? Could it cause serious damage to the shocks to the point that it wouldn't be worth it to get them rebuilt compared to the cost of a new set, or would it just damage the shocks and force me to send them in for a rebuild?

4. Would it be recommended to just get the revalving done now before they're ran, considering the spring rates I'm planning for?

5. I know it's been mentioned before that if I'm sending them in for revalving to get the shaft and body shortened by a half inch each. What is the reason/gain behind that? I believe it was to gain some shock travel when a car is lowered.

6. Are there anything else to consider in regards to Koni yellows to improve their function or performance?

7. It's also been mentioned that the lower standoffs that DG designed are a bit too long, and could be taking away a bit of shock travel. My brother measured the max angle that the DG upper hat can sit in reference to the Koni spring hat and it's about 10°. jtoby stated in another thread that he'd like to see it the upper hat as close to the spring hat as possible at 30°. Since our upper hats don't seem to have this much travel, should we look to shorten the lower standoff so that it's almost touching the spring hat when cocked to its max angle?

Might it be possible to get another spherical bearing that allows for more angle, or would it not be necessary? I would assume not, as if the shock is at that far of an angle from the upper hat, I'd guess I'd have other major issues, but I figured it'd be worth asking.

 

[jtmcinder]

1. What spring combo would you recommend as a max for an autox only setup on OTS Koni yellows?

I liked 850/400, because the car felt solid, loose, but catchable. (Not M3 catchable, but not 2G on Teins uncatchable, either.) It was not a good car to loan to others (as they always spun and hurt the tires) and it was not a good car for daily driving, since you always had to be paying attention. But it was darned fun. Note: I was driving on the street with a bit of front toe-out, which is why you had to pay attention. With zero toe, it wouldn't have been *that* bad.

2. What spring combo would you recommend as a max for an road race only setup on OTS Koni yellows?

No clue, but the guy who bought Cinder said what I had done was way too loose. In fact, any autocross course requiring third gear was a real sphincter check for me. Don't listen to me on this.

3. What would happen to the shocks if I tried to run high spring rates (my current setup is 700/400 and I'm building it to be a road race car)? Could it cause serious damage to the shocks to the point that it wouldn't be worth it to get them rebuilt compared to the cost of a new set, or would it just damage the shocks and force me to send them in for a rebuild?

I'll bet that the fronts would be OK with 700s, partly because that's not as extreme and partly because the fronts seem to get better air for cooling. But 400s in the rear is pushing it. And, yet, I'll bet you won't want anything close to that high in the rear if you have 700 fronts. Use more bar and less spring, would be my suggestion. Maybe way less spring (such as 300s) and an adjustable rear bar so you can loosen the car for autocross and put it back to safe and drivable for the ride home and the open track.

I'm not criticizing your current springs. I'm just guessing that you'll have so much more grip with Konis that you want to make changes. Maybe up the fronts and drop the rears. Not sure.

4. Would it be recommended to just get the revalving done now before they're ran, considering the spring rates I'm planning for?

Nah. Get your money's worth and beat on them first. Plus, you want to get an idea of what to ask for. While the rebound is adjustable over a huge range, there's zero cross-talk, so the compression is fixed. Drive them for a year and then think about what needs changing in October. That's my $.02.

If you're actually to the point of modeling, my memory says front Konis produce about 50# at 2" per second in compression and, again, there's no crosstalk, so that true for all settings on rebound. If you don't feel that the car turns in well enough, you might end up asking for more compression; if it pushes at exit or seems to skitter, you might want less. Drive it for a while and see. At least, that's what I'd do if I had the nerve and the spouse to try it.

5. I know it's been mentioned before that if I'm sending them in for revalving to get the shaft and body shortened by a half inch each. What is the reason/gain behind that? I believe it was to gain some shock travel when a car is lowered.

Exactly. You need the extra 1/2" of travel. Note: when you ask for 1" shorter, Koni will read that as 1" shorter at full extension, so they'll cut 1/2" off the body and 1/2" off the shaft. Thus, 1" shorter is only a 1/2" more travel. They can't do more, so don't ask. But take the 1/2".

6. Are there anything else to consider in regards to Koni yellows to improve their function or performance?

They don't want any side forces. You want a pillowball and coaxial hat at the top and if you can get a spherical bearing for the bottom, do so. It's a darned small shock for a twin-tube. It is not a strut insert by any stretch of the imagination. The shafts are not that strong. No side-forces is key. They'll last much longer and be much better with sphericals at both ends.

(Nice idea for a thread.)

 

[knochgoon24]

I don't know if anyone else cut the Koni bump stops, but that was a mistake. My tires hit the inside of the fenders before the shock bottoms out. My fault for not checking that. Live and learn. At least the shock isn't bottoming out, but the fender liner is just about shot from the studded tires chewing on it. I really need to raise my car up 1/2" - 1", but I've been too busy.

Has anyone in that group buy done any road racing with the setup yet? I have about 12,000 miles on mine. It's been 1 year since I've installed it. IMHO, my setup is way too loose for road racing. I've had a few hairy moments while taking spirited cruises through the central PA mountains. It feels quite neutral steady speed through turns, or even on the throttle a bit, but hitting the brakes mid turn is no-go. The back end starts to feel real light. I'd have to check the alignment sheet again, but I'm pretty sure my toe should be close to zero'd out front and rear.

Installing the RM front sway instead of the stock one should help, but I would NOT want to road race with my setup.

 

[snowborder714]

Great answers - thanks! (Not sure if I ninja edited #7 in my list while you were typing out your response, jtoby.)

I think at one point you mentioned it is a good idea to do a bit of toe out on the front of a FWD car to help counter understeer. Am I remembering correctly? If not, I read something like that somewhere.

I do plan on playing around with spring rates to see how the car handles. I've got a 650/350 combo kind of at my disposal (my brother's setup), but I'd guess the small variance in the front wouldn't net me much different feedback. I would think I may notice a difference in the rear though. I'd like to get another 2 sets or so with varying rates so my brother and I have rates to play around with.

I think I'll have to do some reading over the next year or so about shock tuning. I have no idea what I should be feeling for to direct someone on what I'd want after revalving.





Wes, thanks for the input. Eric and I were just outside measuring for spacers for the shocks to keep the SPC front arms out of the shock towers and the rear tires out of the fenders. Eric noticed my rear drivers side tire has a nice line it in that's been cut by the fender (not sure how we've missed this before), so I really need to get this taken care of so as to not completely ruin my tire. I also need to roll the fenders soon.

I think Scott is the only person who's raced on them, but then again, he doesn't have a full DG setup. Everyone else either isn't a road racer or their car is down. I hope to get out this summer, but we'll see if that happens.

If you could change your setup to be less loose, what would you change?

 

[jtmcinder]

Yep, I missed that one.

7. It's also been mentioned that the lower standoffs that DG designed are a bit too long, and could be taking away a bit of shock travel. My brother measured the max angle that the DG upper hat can sit in reference to the Koni spring hat and it's about 10°. jtoby stated in another thread that he'd like to see it the upper hat as close to the spring hat as possible at 30°. Since our upper hats don't seem to have this much travel, should we look to shorten the lower standoff so that it's almost touching the spring hat when cocked to its max angle?

Yes, but I guess I should add, given what Wes said, that you only need to go nuts about shock travel if it's the limiting factor. If your tires are already hitting or, for some reason, your upper arm hits something first, then you need more bumpstop and have no need for more travel.

All of this reminds me that there are two very different approaches to setting up 2Gs for autocrossing. There's the "classic" approach with smaller tires (e.g., 245/45/16s) that tuck and a low car. This is a left-over from ESP. Sean Caron was the master of this set-up and Sam Krauss still runs it. And then there's the "monster-truck" approach that was pioneered by DG and still is used by Scott McIntyre. The latter approach never has shock-travel issues because the car cannot be lowered with 285s or 315s or whatever they run.

Might it be possible to get another spherical bearing that allows for more angle, or would it not be necessary? I would assume not, as if the shock is at that far of an angle from the upper hat, I'd guess I'd have other major issues, but I figured it'd be worth asking.

You don't need more angle at the top (or bottom). The issue is a lower spherical to match the upper pillowball. That takes work, but DG has done it and, I believe, ACM has, too. Odds are, so has Scott, so I hope one of these guys logs in.

 

[jtmcinder]

With regard to looseness and drivability, I tried to keep what I call "Fedja's Law" in mind: you won't spin if you don't lift. Thus, dump speed early and get back on it. Trail-braking is what you do when the car is not set-up correctly. With the car set up nicely, slow in and fast out rules. That took me a very long time to really get nailed down. I kept the trail-braking habits from the OE set-up way too long.

 

[knochgoon24]

I do plan on playing around with spring rates to see how the car handles. I've got a 650/350 combo kind of at my disposal (my brother's setup)...

I got lightly used Hyperco springs off eBay for something like $25 shipped each. I bought myself a set of 200# springs with the intention of moving the 350's to the front for the winter, putting the 200's on the rear, and raising the car back to stock height. I never did do that.

I did notice rust starting to form on the Koni shock bodies already. I sprayed mine with a couple extra coats of clear before I even installed them because I heard it was a problem. Grrrr....

Wes, thanks for the input. Eric and I were just outside measuring for spacers for the shocks to keep the SPC front arms out of the shock towers and the rear tires out of the fenders. Eric noticed my rear drivers side tire has a nice line it in that's been cut by the fender (not sure how we've missed this before), so I really need to get this taken care of so as to not completely ruin my tire. I also need to roll the fenders soon.

I rolled and pulled the rears on my car pretty hard, so that didn't give me trouble. But my fronts did rub the front fender and slice the tire if I hit a hard bump with the tire turned. It didn't happen too often with the shocks set stiffer, but with them set softer to DD, it happened every couple days. Again... too low.

If you could change your setup to be less loose, what would you change?

The RM front bar will be the first thing going on. Setting the car to an appropriate ride height will also help. But I think more seat time will make the most change.

..I kept the trail-braking habits from the OE set-up way too long.

Me too. Still have that habit. I'm just not used to it yet. I've never owned a RWD car, so this whole oversteer thing is new.

 

[romeen]

Take the following for what it's worth because I haven't gotten an alignment since raising the ride height.

Nonetheless, I'm currently running 500f/325r Hypercoils on Koni Sports. The car is definitely loose. Twice the rear has started to come around quite suddenly at mid corner. But I also have front and rear RM sway bars. Don't know if a rear STB has any affect on this but I have the DC Sports rear bar which is very well made and very rigid.

I'm going to be changing the rear springs to 275 lbs.

 

[snowborder714]

Very interesting. I've been having issues with understeer (typical for these cars, and FWD moreso), so if my car gets oversteeer, that'd be a whole new feeling. I also have front/rear RM sway bars and a rear DC strut bar.

 

[romeen]

I forgot to mention an important point. I have different tires front vs rear. Kumho Ecsta MX up front and Bridgestone SO-2's on the rear. The SO-2's are older and quite worn.

In hindsight, given the need for an alignment and the different tires my post does not seem very helpful now. Sorry.

FWIW, both incidents happened very suddenly at mid corner so I was beginning to straighten the car out. Both times it was brief and the rear seemed to catch itself before I could react so I think I got lucky. It was definitely disconcerting.

 

[jtmcinder]

Definitely fix the tires and alignment first. I can't see any way for 500/325 to be the problem.

Not lifting, are you?

 

[romeen]

Definitely fix the tires and alignment first. I can't see any way for 500/325 to be the problem.

I completely agree. Just got back from driving the car on wet roads and the rear is all over the place. Frankly, it made me nervous. Looking closely at the rear tires I can see with the naked eye that the front of the tire is angled in towards the centerline of the car (toe in, correct?).

I honestly won't be offended if my posts are deleted since they could be misleading with regards to spring rates.

Not lifting, are you?

No. I slow down before I get to the turn and then apply steady throttle (or increasing throttle) through the turn. Is that what is meant by trail braking?

 

[jtmcinder]

Yep and yep.

For others that may be confused, trail-braking is still being on the brakes at turn-in. The idea is to shift weight forward for more front grip to get your pig ... er, DSM ... to turn. The OE set-up understeers terribly and this can be the only way to get the nose around. The downside, however, is that doing this too much can cause an uncatchable snap-spin, instead. It's best done with left-foot braking so that you can quickly and smoothly add gas and delete brakes if you've over-done it. That's the only way that you'll catch it in time.

 

[knochgoon24]

I have lots of videos to show what happens when you don't catch it in time, and I also have lots of other videos that show me still trail braking like the worn out OE suspension is still on it.

JT, I wish CRP SCCA would get more events at Mid-State. They've moved most of the season to a tiny little parking lot where CRX's and Miata's rape. I still have to trail brake there because it's so tight. Oh well.


Since tires have come up, has anyone found anywhere with RS-3's in stock?

 

[19BLACKGST98]

Ive honestly hated driving my car ever since I put the koni yellows on. I am not a road racer but the person that suggested that particular brand to me is. Anyways since I installed them my car bottoms out on everything. I have Eibach pro springs on now (and have since before the koni's) but would it make the car more enjoyable to drive with different springs on it? My GST is used for some weekend fun and passes at the drag strip. Any info would be appreciated.

Edit: (I had to have my fenders rolled to keep them from eating up my Drag Radials)

 

[jtmcinder]

Did switching to the Konis lower the car? If so, then you probably have the snap-ring in the wrong groove.

Alternatively, if it just feels like it is bottoming out, the odds are you have the rebound set so high that the shocks are packing down the springs. Run them near full soft and see. Prokits are very low-rate springs. They don't need much rebound.

 

[19BLACKGST98]

They were installed/adjusted at a shop that specializes in auto cross/road racing...I took the car back after a week thinking the same thing. After removing and reinstalling them they assured me they were set up correctly.

They did lower my car quite a bit from the factory set I had on before.

Ive been running them full stiff because the softer I adjust them the more the car gets banged up.

If this sounds incorrect can you show me a pick of the snap ring in the correct location?

 

[jtmcinder]

It's been a while since I had a Koni in my hand, but I know that there are two grooves in the body. If the incorrect one is the lower one, then you'd end up the way you are. In any event, swapping from dead KYBs to Konis raised my car a tiny bit. Swapping from good KYBs to Konis might lower you a tiny bit (since KYBs are high-pressure and Konis are low-pressure), but it should hardly be noticeable. If the car dropped a lot when they swapped the shocks, assuming same springs, then the shop screwed up.

Oh, and turn them down. A Koni Sport will pack a ProKit down. That'll kill the ride.

 

[romeen]

It's been a while since I had a Koni in my hand, but I know that there are two grooves in the body. If the incorrect one is the lower one, then you'd end up the way you are. In any event, swapping from dead KYBs to Konis raised my car a tiny bit. Swapping from good KYBs to Konis might lower you a tiny bit (since KYBs are high-pressure and Konis are low-pressure), but it should hardly be noticeable. If the car dropped a lot when they swapped the shocks, assuming same springs, then the shop screwed up.

Oh, and turn them down. A Koni Sport will pack a ProKit down. That'll kill the ride.

The rear shocks have two grooves but the fronts only have one.

 

[19BLACKGST98]

It's been a while since I had a Koni in my hand, but I know that there are two grooves in the body. If the incorrect one is the lower one, then you'd end up the way you are. In any event, swapping from dead KYBs to Konis raised my car a tiny bit. Swapping from good KYBs to Konis might lower you a tiny bit (since KYBs are high-pressure and Konis are low-pressure), but it should hardly be noticeable. If the car dropped a lot when they swapped the shocks, assuming same springs, then the shop screwed up.

Oh, and turn them down. A Koni Sport will pack a ProKit down. That'll kill the ride.

The ride is terrible...like riding in a dryer .

Im pretty sure romeen is right because the shop took off the fronts to try to step the konis up...ill check the backs later this week.

What Springs would you recommend?

when you say turn them down do you mean softer?

 

[romeen]

The ride is terrible...like riding in a dryer .

Im pretty sure romeen is right because the shop took off the fronts to try to step the konis up...ill check the backs later this week.

What Springs would you recommend?

For a conventional type spring I would recommend the H&R OE Sports. Although I have no personal experience with them, other members have been very happy with the pairing of these two. H&R wont say what the spring rates are but many believe them to be 460/230 which is, if accurate, a great match with the Konis. They lower the car only about an inch so you're able to maintain relatively good suspension geometry and travel. Take note that H&R makes OE Sport (note the "OE") as well as Sport (no "OE") models. The Sport springs (non-OE) lower the car a bit more than the OE Sports but are believed to have the same spring rate. Here's a review:

http://www.dsmtuners.com/forums/art...s/242876-2g-koni-sports-w-h-r-oe-springs.html

when you say turn them down do you mean softer?

Yes. Specifically he's referring to the rebound. On Koni's turning the adjustment knob CLOCKWISE lowers the rebound (makes them softer ) and vice-versa.

 

[ACM]

Mid-corner snap-oversteer can be a sign of insufficient camber in the rear, which in turn an be caused by too soft springs/dampers for the available tyre grip.

The fact that you have Eibah kit springs does mean that you're doomed to mediocrity, so don't expect too much unless you have pool-table-smooth roads.

Where are your Konis set now ? To answer that question, install the adjuster knob and count how many turns ANTI-clockwise (your other left Darryl) it takes to get the adjuster to bottom out - DO NOT FORCE THE ADJUSTER.

Anything over 1 turn means you have something to work with.

You two Koni users - have your bumpstops been cut, and if so, by how much. The more they are shortened the worse the ride becomes. Eibachs always ride on the bumpstops, so the more progressive the bumpstop, the less ugly the ride. Which brings a cheap fix into view - try installing a bumpstop that is long and very progressive - that should reduce the harshness. Such a bumpstop will always be "in use" so there is no longer the initial impact of contacting it (specially cut ones).

The ultimate fix is as Jtoby always notes - get a decent set of springs. Eibachs Pros are barely any stiffer than stock, literally just 10lb/in or so, they're just a couple of inches shorter, they will never work out in the real world. I will say however, that the Pro kit front springs make a very pleasant riding solution when fitted to the REAR of a 2G AWD - that's my winter suspension.

 

[PieEyedPiper]

I will say however, that the Pro kit front springs make a very pleasant riding solution when fitted to the REAR of a 2G AWD - that's my winter suspension.

You have no idea how many times I've wondered about that.

 

[Black95TSIawd]

You have no idea how many times I've wondered about that.

Sorry to bump an old thread. Been searching koni's for the past few days.

What do you guys mean exactly? The rear prokit's with koni's are great for a soft/comfortable ride?

 

[ACM]

Sorry to bump an old thread. Been searching koni's for the past few days.

What do you guys mean exactly? The rear prokit's with koni's are great for a soft/comfortable ride?

No - the front Pro Kit springs make for great rear springs - they're around 260 lb so they give good grip and ride with snow tyres. That should give you an idea of how badly wrong Eibach got it...