Reid Fleming

iTrader: (2)

Like many TGO members, I debated going either Bilstein or Koni yellow when it comes to struts and shocks. My previous experience with Bilsteins was on new (at the time) C4 Corvettes. I liked them. My wife also has Bilsteins in her Blazer. But that's a whole different setup. I even debated going with Koni Reds in an effort to keep the car more comfortable compared to the bone stiff yellow choice.

I'm glad I didn't buy the Reds. The Yellows are wonderful, even on the rough roads here.

I'd heard that Bilsteins were great for a high performance street car, while the Konis were more for all out race cars and would be too much for a daily driven street car......On the other hand, I'd also heard that Konis were better for a daily driven car because you could adjust them soft, while the Bilsteins were a one size fits all.

I live in Houston, TX where the roads are concrete and we have Michigan grade pot holes. My car is also a daily driver. Although it's 22 years old with 50,000 miles on it, it was time to replace the struts/shocks.

I started with the back first. Moog 5665 and Koni yellow shocks.






My old springs had a code "NNL" tagged on them. The original WS6 springs. Compared to the new Moog 5665, they look pretty much the same to me. I was surprised that the old driver side spring wasn't shorter than the old passenger side due to ride heights (see below)

Ride Heights

This is a topic that comes up often. What is the stock height? What should a car with lowered springs sit at? What are the heights of an original suspension that's been aged? For this, I compare my car 100% bone stock vs hellz_wings' 88 IROC vs my car now. hellz_wings' car already has 5662/5665 but has 4th gen rear isolators. I re-used my original 3rd gen isolators.


hellz_wings' IROC (5662/5665)
LF 28.5 RF 28
LR 29 RR 28.25

GTA (mine, 100% stock)
LF 26.8 RF 27.75
LR 27.5 RR 28

The differences are below.

1.7......0.25
1.5......0.25

I'm not surprised by the vast difference in sag from side to side. 99% of the time, I'm the only person driving the car. And I'm 230 lbs.

So right off the bat, it appears I have very little sag on the passenger side. But the equivalent of a Eibach Sportline setup on the left. My car is the perfect example of car where if I'd bought "lowering" springs (Pro Kit), my height would have gone up.
I'd noticed that the driver's side was looking low. And I honestly don't care for the low ride. I prefer stock height. (Houston roads are flat as a pancake and flood easily and thus have STEEP hills turning into gas stations, grocery stores, driveways etc). I also don't want to worry about running over something small on the highway because of a lowered car. Plus I just like the better ride quality of stock height. Stay off those bumpstops.

My rear height after install is as such.

LR 29.25 RR 28.5 (unsettled, immediately after install)
LR 28.5 RR 28.5 (settled...1 week later, after having driven around with people in the back seat). My rear isolators looked great. No problems there.

All height measurements are taken with nobody in the car.

So I gained 1" on the driver side and 0.5" on the passenger side. Nice level side to side result. I really like the result. At first, I was a little leary that it was too high. But with it settled and getting used to it, I'm thoroughly pleased. I can actually see the tread on my GS-D3 tires now. I can see the GMMG muffler in the back now.

But enough about the springs. How are the Konis? Remember I've only done the rear springs and shocks. Front springs and struts are shipped, but not here yet. This gives me an interesting comparison between stock vs Koni.

For starters, I went with the 0 click (full soft) setting. I'll probably leave it there. Full soft is not mushy. It's the quickest response I've ever driven on. Driving on rolling hills at 40 mph, the front end of the car will bounce like a small boat in rip tides. The back end of the car is level and planted as if the road is perfectly level. Driving on sweeping turn freeway overpasses at 60 mph, you can feel the back of the car level and firm, while the front end wants to twist. The faster you go, the more the sensation you get. On bumps in the road, the front end goes "boom" while the back end is a much nicer "blump." The rear also settles back to normal much faster after having driven over a bump in the road.....When my car was stock on both ends, the rear was actually worse going over bumps than the front.

Now my car is not a full out autocross car at all. But with just the rear Konis and Moog 5665 setup, I've noticed that spinning the tires while pulling out of a parking lot. Or on a city street, that the car is much easier to control. You don't get the weight transition sloshing around when you let off the gas and the car hooks. It's much more predictable.

Are the Konis good for a daily driven street car that's not raced? Absolutely yes! I should have done this years ago.

I'm looking forward to getting the fronts done sometime in the next week or two. If for no other reason to get that front driver's side up from the 1.7" lowered stance to the stock height stance. It looks way too low the way it is right now. Hard to wash the top of the tire too.

Cliff's Notes: Love the Konis. Buy them even if you don't plan on racing. The Koni/stock height combo is in my opinion the best of both worlds. Good handling but can still go over speed bumps.

I'll update the thread when the fronts are done.

Guest

Pull the Koni Yellows out of the rear and just leave the springs with no shocks in there and the car will drop at least a 1/2".

The Koni's are gas charged and will lift the ride height slightly.

If you just simply stuck the Koni's in with your old shocks your ride heights would have changed and very likely evened out- very possible your shocks were just blown and th edrivers side (which you sit on most obviously) is generally in worse shape than the passenger side shocks.

interesting note for all: you will also notice this with brake pads. The left side brake pads will pretty much always wear fastrer than the right side pads because thats the side carrying more of the vehicle weight.

ps- and by no means is a Koni Yellow designed to be an all out race shock- not by far. It is intended for street cars.

On that note- What is a race shock? It has to do with valving, heat dussapation, anti foaming of the oil, separate low and high speed piston rates (some shock do this with digressive valve disks, others do it in a 4 way adjustable disk that will control low and high speed rebound, and low and high speed compression. Low spped movement is usually considered when the piston moves internally between 0-10inches per second whereas the high speed damper disk controls faster piston movement between 10-25 inches per second (those harsh high vehicle speed pothole hitting movements or the shock shaft)

Valving resistence and quality of valve disk is really what makes up the property of a race shock. Most high end race shocks have remote reseviors or if not, they have large aluminum bodies for heat control. Koni Yellows do very well on tracks but do fade and are not designed for all out race use with the steel bodies and small oil capacity.

Reid Fleming

iTrader: (2)

I actually wondered if it was truly the springs or the shocks themselves that were blown. But for $50 and essentially zero labor on the back to change springs (when changing shocks), I figured what the heck. Why not do both?

The front springs arrived today. Now I feel like a kid 2 days before Christmas waiting for the front struts to arrive.

Interesting info about remote reservoirs on racing shocks. I wouldn't think the remote reservoir would be close enough to react fast enough. But racing shocks are far beyond my knowledge level. Where would a remote location typically be located at?

Guest

I would have done the same.



Penske, King, Afco,etc....the list goes on. See attachment. Most manufacturers like Koni for instance makes a very upscale strut assembly that would need special fabrication to fit into whatever you want it to. You need to be proficiant at fabricating and welding to make one fit into a third gen but it is doable.

Guest

Here is the technical page on the Koni race series struts.

http://www.koniracing.com/8611.cfm

hellz_wings

iTrader: (2)

Hey Reid,

Any news on installing the front moog springs/ koni struts yet? I'm a button away from ordering front and rear koni yellows.. Summer is coming soon ohh yea!

Also, are the rears on-car adjustable or do you need to pull them out to adjust?

//<86TA>\\

iTrader: (14)

the 4th gen rear ones are available with the on car adjuster, just like the fronts FYI.

Reid Fleming

iTrader: (2)

Actually I put the front Koni struts in this past weekend along with a TDS Wonderbar. I didn't have time to change out the springs to the 5662 yet.

The front Konis are outSTANDing. Seriously, I can't believe how much of a difference they've made. I installed them in the full soft position to start with. They are not mushy at all. Even driving at 5 mph in a parking lot, it feels completely different.

They make more of a difference than the rear shocks did. The rears changed the way the back end feels. The fronts changed the way the front and center of the car feels.

I can't say for sure what is due to the Konis and what is due to the wonderbar. But combined, it's made one heck of a difference. The front end of the car feels about a 100 lbs lighter. But at the same time, the front tires feel glued to the road. Steering effort is easier at any speeds (which feels strange at first, but now I'm getting used to it and liking it more and more). But at the same time, you feel more in contact with the road (a good thing).

I've been driving for a few days with it and am still getting used to it. I don't know what the handling limits are now. Speed bumps are a breeze now. Rolling hills are now flat. Drop offs which would bounce the front end twice now do nothing. I find I'm driving faster over roads to work and back than I used to because it absorbs the bumps much smoother now. And corners are so much easier to contend with.

I would describe the Konis the same way that I describe the "modified" Trans Go shift kit that Pro Built Automatics sells. Everything is crisper, quicker, firmer, but not stiffer. A great combination for a daily driver that also satisfies what you want, when you want to "get on it."

The rear shocks are not "on car adjustable." You need to put the back seat down, pull the carpet back. Undo the bolt there. And undo the bolt underneath the rear of the car. Nothing too time consuming. But I really like the way the car handles and drives with the rears set on "0" (full soft).

For the fronts, it's much quicker. Pry the dust boot off with a small flathead. And then put the **** on and turn. I may try turning the fronts up a 1/2 or 1 full turn (360°). But honestly, the car performs so well with the full soft position up front that I may just leave it there. I'd like to try it out with the new 5662 springs in front before I go messing around.

While I had the two front tires off doing the struts, I noticed a huge difference in tire height (I have 1 Goodyear GS-D3 and 1 Michelin Pilot Sport A/S up front. Both rear tires are GS-D3).....The only reason for the one Michelin up front is that I got a non repairable flat back in January and Goodyear isn't selling GS-D3 tires in the stock size anymore. So I'm probably going to buy another Pilot Sport A/S for up front for a matching set. I'll check the tread depth on the back GS-D3 tires as well. They might be due for replacement anyways. So bottom line, I'm looking at 1 or 3 new Michelin tires for the car. With the one taller tire up front, I have an alignment issue (car pulls to the right)

The tire costs may prohibit me from buying a J&M Hotparts front upper strut mount set (solid bearing). The stock rubber strut mounts were still in good shape when the stock struts came out. But I know even with the rubber setup in good condition, I'm leaving some performance behind by not getting the solid bearing strut mount. If I end up buying 3 tires, the J&M will have to wait. If I buy 1 tire, I may pick up the J&M in a few weeks.

The car really does feel like a whole different car altogether now. Better than when it was new. It's taken Houston's miserable pot hole city streets and concrete line highways and made them a non issue. There is a raised bump followed by a drop off about a block from where I live. With the stock front end, it would dip down at 30 mph, drop at 40 mph, and barely get airborne at 45 mph.....With the Konis up front, I went over it on the way to work today at 40 mph. Nothing! It just went uphill and then down. No compression. Tires felt glued the entire time. It's hard to believe that it can adjust that fast to road conditions.

Even something as simple as changing lanes at 60 mph, it feels better. The stock setup would do that easily enough. But the way it feels now, you just have that glued to the road feel.

One last tidbit. When I leave home, I have to crank the wheel to full lock while backing out. Before, when I got to about 90% lock, you could feel something. It wasn't really straining or making noise. But you knew you were at the end of something....With the new Koni/Wonderbar, it feels no different than it does at 50% turning. I suspect that's the Wonderbar tightening up the front end from twisting.

Cliff's notes: Buy....the....Konis

Immediate future plans are to do the 5662 and get 1 or 3 tires. Then the upper strut mounts. Then subframe connectors. I may try turning up the front Koni settings just to see what the difference is. But the full soft position seems to work quite well for front and rear. I would say that the fronts are a tad softer than the rears. But then again, I haven't put the 5662's in yet. And I hear they make the front end stiffer than the original springs. So we shall see.

I had no idea that high performance suspension would make normal everyday driving so much more fun. I knew it would help for high speed cornering. But was blown away at how much nicer and more fun it is to drive the car just on a regular commute to work and back.

P.S. My left front height went up by aprox 0.4" with the new strut. I still want to get it up to proper stock height though. The TDS Wonderbar fit like a glove. You couldn't ask for a better fitting piece.

hellz_wings

iTrader: (2)

Sounds like the Koni's are a must... I'm sure that replacing the stock shocks and struts must feel refreshing especially when going to Konis.

The 5662 front MOOG springs are wayy stiffer than old stock springs. You will feel a huge difference by installing these over stock. Front end will bounce less and be much more responsive and you will have much less body lean.

Installing subframe connectors will give you a huge improvement in how the car feels. When I first got mine installed, changing lanes went from tight and precise to feeling like it's on rails! I'm not exagerating! My car was not rusted at all so the chassis was still in great shape when I got them welded in. You will definitely see a huge improvement and you should definitely get them as it's hands down one of most noticeable mods I've done (that along with going from open 2.73 to posi 3.73 lol).

It sucks that they're not really 'on car' adjustable in the back, would have been great if that were the case, oh well..

86TA: You mentioned the 4th gen rear ones were on car adjustable? Do those fit on our cars and do you know the difference between the two?

Reid Fleming

iTrader: (2)

Well now I REALLY want to get those 5662 springs put on.

I've heard nothing but good things about subframe connectors.

The 4th gen cars sometimes will use a 3rd gen rear Koni shock as a cost saving measure. (Save $100). If you're not planning on fine tuning the adjustment, it seems like a fine thing to do. On the other hand, the $100 extra for the 4th gen rears is a one time shot.

3rd gen and 4th gen rear shocks are slightly different. One set is a monotube. The other is a twin tube. I'm not sure which is really better.

Norm Peterson

I have the ****-adjustable Koni yellows all the way around on my '08 Mustang, and I can tell you that you absolutely will feel the difference that 1/4 turn makes. Even eighth turn adjustments are perceptible. What most people will do is tinker just a little in the beginning until they find settings they are happy with, and then leave them alone. You might after many thousands of miles tweak them up a little to compensate for internal wear, and you'd probably adjust them if you were to swap springs again. Note that there is no particular reason for the fronts and rears to end up being set the same, and if you've got aftermarket springs they probably wouldn't be.

I've seen exactly one locally/regionally competitive autocrosser dial some damping out of his Konis at a wet autocross. Once.


This thread has me wishing I'd put 5662's (~700 lb/in) or 5664's (~750) in the front of the Malibu instead of the 5660's (~600 or ~640 depending on where you look). 5660's are still an entirely decent-riding street spring, just a bit too soft for autocross. I can't imagine 5662's being tremendously different - as in being a deal-breaker amount stiffer.


Norm

hellz_wings

iTrader: (2)

Another good thing about the Koni's.. DAmn you guys are going to make me poor lol. For an occasional street driver that goes to the track a few times during the summer, what setting would you recommend for the koni's (on Moog 5662 and 5665 springs)?

The 5662 springs are 700lb springs so they are a good bit stiffer than what stock was when they were new.. But I will say that they were much stiffer than 22 year old stock sagging springs. The stiffness was very noticeable. I wouldn't be able to tell you the difference between the 5660 (600lb) and the 5662 though..

Norm Peterson

Best thing is for you to test-n-tune them. Koni has a double-adjustable tuning guide that you can just skip over the bump damping part and follow the rebound damping only ("yellows" are single-adjustables, rebound only). I may have a copy here (work), but basically you start at full soft and add stiffness.


I don't have my Moog book or my R&T 3rd-Gen article handy (the R&T piece lists all of the then-upcoming 1982 spring and bar combinations for both F-bodies), but your OE springs could have been ~350 for a base suspension and probably not much over 400 unless your car was a Z28 or TA.

350 to 700 is a bigger step than 400 to 600 (mine), but I didn't feel that the 50% increase changed the ride much at all, less than about what 5 psi more tire inflation gave. I think there was a bigger ride quality difference between the KYB shocks I had on the car at one point vs the Bilsteins I had later.


Norm

Norm Peterson

Found it.


Norm

92RS(real slow)

If any one is looking into buying koni's tirerack has them on sale right now. That's where I got mine from bout 200 bucks off the whole set. Now just to waiting to get my new brake kit in to take it for a spin can't wait

FryeDaddy

iTrader: (1)

http://www.tirerack.com/suspension/s...85&autoModClar=
Is this what you talking about? Not sure if this has shocks and struts, which I been looking for now. New to suspension, those numbers are confusing me but thinking about gettin rear lifted because my tail pipes like touch the ground on a bump or should i get the shocks and struts and it fix it? Pricing is debatable for me cauz I want to get good suspension but if not much different from monroe then I stick with monroe.

Norm Peterson

That's them. Put these on the car you're going to keep. Adjust as per the note posted above.

Monroes, particularly the Sensatrak line, are what you put on the car you're about to sell/trade so that you can legitimately claim that it "has new shocks".


Give Sam Strano a call (phone number at www.stranoparts.com) and get an opinion that carries more weight than mine. I think that he too is offering Konis at a substantial discount off normal list, at least that's how I read the pop-up on his page.


If your pipes are scraping, you need to fix the exhaust by hanging it up a little higher or otherwise re-routing it.


Norm

hellz_wings

iTrader: (2)

Hey Reid,

Wondering if you had the opportunity to put in the 5662 front springs yet? My Koni yellows are on the way right now, but want to hear your feedback if you have them all installed! Thanks

EDIT: Noticed you wrote 88 IROC at the top for my car! It's an 86 :P

Reid Fleming

iTrader: (2)

Unfortunately, the front springs are still sitting in the box. I just got back from vacation in British Columbia. I "should" have them installed sometime in the next month. It's getting hotter by the day here. So sooner is better.

How did I think you had an 88? I think it must be that I used to have an 88 black Iroc with the gold wheels.

Reid Fleming

iTrader: (2)

It's time I updated this thread. Things that have changed since early 2011.

• Front Moog 5662 are on
• Global West Del-Alum are installed
• Went from 3 Goodyear GS-D3 and 1 Michelin Pilot Sport A/S to 4 Michelin Pilot Sport A/S

The stock ride height question is even more confusing now, because the tires made a difference in ride height. My car right now is the following heights.

LF 27.3 RF 27.5
LR 28.75 RR 29

Notice how my rear heights are 0.25" and 0.5" taller than they were in Feb 2011? It's because I have Michelins on the back instead of the Goodyears. I equate the driver's rear being slightly lower than the passenger's rear because 99% of the time, it's just me driving around. They used to be exactly the same after the rear spring install.

Both sets of tires are the same 245/50/16 size. But the Michelins are taller and narrower than the Goodyears were. When I originally started this thread, I had 1 Michelin on the front driver's side and Goodyears everywhere else.

How much did the Moog 5662 change the front heights?

LF +0.5" RF -0.25"

I probably am in the minority, but I thought the front would be higher than it is. However, what it did do was give the car a perfect raked look. Just a teeny tiny bit of a rake to it. With the rear end being aprox 1.5" taller than the front. When I walk towards the car now, it almost looks like the back end is lower than it used to be. Front still seems fairly low. But it's just that the front/rear balance is better now.

The Del-Alum are great. No roughness to them. Corners nicely. Street friendly? Absolutely. My original rubber ones weren't too bad. But they were old after all.


I agree. I found the new front springs to be a great street friendly, yet still firmer than stock feeling. A noticeable upgrade that doesn't sacrifice ride quality for performance. I think it actually takes the bumps better than the stock springs did. I thought I might need to turn the front Konis down a bit after the new springs went in (they've been at 1/2 turn from full soft for a lonnnng time now). But I left them the same.

The bottom line is that the Moog 5662/5665 and Koni combo is a very nice setup. Performs well, while still being decent in terms of minimizing ground scraping. Unfortunately I still scrape the front air dam from time to time. But that's just the nature of living in the city I do. (Houston is flood prone, so absolutely every driveway and shopping mall/gas station/restaurant has a steep incline up from the street)

hellz_wings

iTrader: (2)

Those ride heights in the front are pretty low, mine were a tad higher but my front probably weighs less than most on here (with SBC iron headed engines) because i've done tons of mods + relocate battery to rear. I am at about 27 to 27.5 in the front now with the extended ball joints and it's about as low as I'd want to go on the street, and handles like a dream.

I have poly bushings in my front control arms, but i have read that del alums were the best all around. How about noise? Are they squeak free or do they squeak like my poly's do?

Reid Fleming

iTrader: (2)

How did I know you'd post here?

No squeaking from the Del-Alum....Now the front brakes on the other hand. They're next.

hellz_wings

iTrader: (2)

that's awesome, going to get me a set of those eventually..

and yes, this is suspension talk, OFCOURSE i'll post here! :P

ragtopday_z28

Hi, I've been following this discussion and have a few questions. According to the Moog website, the rates for the springs are as follows:

5660 598#/inch (http://www.moog-suspension-parts.com...prod=MOOG-5660)
5664 707#/inch (http://www.moog-suspension-parts.com...prod=MOOG-5664)
5662 748#/inch (http://www.moog-suspension-parts.com...prod=MOOG-5662)

If you calculate the spring rates using the other information given with the following equation, Rate = Load/(Free Height - Install Height), you get:

5660 613#/inch (not a big difference)
5664 767#/inch (a big difference)
5662 748#/inch (the same)

So, I'm curious where you guys got your rate information from, 5662's (~700 lb/in) or 5664's (~750), or did someone mix up the numbers? I'm not sure how to explain the big difference with 5664's rate between listed and calculated.

I currently have 5662 front and 5665 rear with a set of Koni reds (not made any more) and love the setup!

Reid Fleming

iTrader: (2)

It all depends on where you read the ratings for the 5662 and 5664..... Some websites have the 5662 listed as 707 lbs. While others have them listed as 748 lbs.

The same holds true for the 5664. Some have them rated at 707 and others have them listed at 748.

I "think" Moog recommends 5662 for IROC's without A/C and 5664 for IROC's with A/C or IROC convertibles......but on the other hand, you will see more 5662 = IROC cars listed on the internet when you look up applications. The 5664 is generally recommended more for trucks and Blazers etc. (Although to complicate things, our Blazer uses the same 5662 replacement springs)

My car is a GTA coupe with air conditioning.

It's a confusing issue. Even Moog doesn't seem to know all the facts for sure. They recommend the CC-635 rear springs (cargo coil) for all V8 F-bodies. They don't list the 5665 (linear coil) at all for our cars. Yet, it is the preferred rear spring from what I can tell.

I think you can pretty much flip a coin and get the same result when it comes to choosing 5662 vs 5664 for F-body front springs.

Scamo-2.8

iTrader: (16)

Guys I gotta say, great review of the shocks.
I put the Koni yellow rears on this year (didn't get the car on the road though) and will get the fronts when they come on sale again this year (if they do go on sale). I was stuck trying to figure out between the 3, Bilstein or Konis (red or yellow). I did the exact same thing, turned them right down to zero.
Thanks again

LiquidBlue

Hey Reid, Jim from Austin here.

Are you still using this same setup and still liking it? Any lessons learned? My 1990 Formula w/ WS6 suspension, and big heavy wing in back should be pretty close to the same setup as you have. I do have the 305, not sure if there is appreciable weight diff up front.

As far as I can tell, every cross reference I've found calls for the 5662 's up front for this application. However, as you elude to in your post, there is some debate between the rear springs. Mood CC635 -vs- 5665. The CC635 a variable rate spring while the 5665 is a constant rate spring. I'm thinking maybe they called out the CC635 to accommodate for all the different spoiler types and wiper combo's. Essentially the CC635 will accommodate the variable rear end weights and still get the job done, where the 5665 would not.

Anyway, I was curious if you are still happy with your setup and if you have anything more to add now that a few years have gone by and probably have learned a few tricks along the way

Thanks for your input and anyone else who care to chime in.

Norm Peterson

Cargo Coils are typically called for where the vehicle is expected to carry high loads - where the corner weights can vary by large amounts. Like hundreds of lbs difference per spring from 'normal' to 'heavy'.

The amount of shock damping needed depends in part on what the spring rate is, and whether you're seeking best ride or best tire grip. With variable rate springs it is tougher to settle on damping that is firm enough for the stiff part of the spring's range without being too firm for ride heights around the softer "normal" ride height. For load carrying purposes, this isn't nearly as critical as long as there's enough damping to settle the chassis motions down in a reasonable number of cycles after hitting bumps and such. Presumably you won't be going nearly as fast with over a quarter ton of iron blocks, heads, and transmissions in the trunk as you would around a road course with the jack, spare, and everything loose removed.


Norm

LiquidBlue

I called Eibach, Hotchkis and Vogtland yesterday. For our application, all of these guys are doing a variable spring in back. Vogtland takes it a step further and also puts one in front. Confused more than ever on springs! There is a good Vogtland post over here, explaining their technology. I did ask all of these guys for spring rates, and Vogtland specifically asked me not to post the numbers. I will say, the numbers they gave me are not what is listed over on this post. I think the spring design makes it possible to call out anything and be correct. Suffice it to say, non of these guys springs are as stiff up front as a 1990 WS6 Formula w/ 16" wheels and A/C replacement spring that Moog calls out as OEM replacement. Rears are comparable. Eibach is close to a 1990 Camaro IROC that Eaton calls out as OEM replacement. Eaton doesn't list Firebirds, that's why I checked Camaros.

https://www.thirdgen.org/forums/susp...-stocking.html

Thirdgen89GTA

iTrader: (5)

The Vogt Lands aren't variable rate. They are dual rate, there is a clear division (you can see it too in the pic below).

The dual rate allows the car to seat on the spring fully even with the suspension at full droop. But when the weight of the car is on the springs the lower rated section is completely compressed to full coil bind.

The top spring is a front spring, and the bottom is the rear spring.

TTOP350

iTrader: (8)

I'm going to have to try these out once i find the strut/shock partnumbers...

LiquidBlue

Thanks for the clarification. That was discussed in the thread I linked to, sorry I got lazy with nomenclature, which could be misleading, I shouldn't have done that. Are you guys finding you are needing a bump steer kit when you lower your cars with these springs that drop ~ 1" ?

Thirdgen89GTA

iTrader: (5)

Its a long thread, lots of stuff to miss.

I don't have them installed. However, the Balljoint in the picture is a .5" extended one that I'll be putting on the car when I install my rebuilt A-arms with Del-A-Lum bushings and stuff. Just going to redo the entire front of the car in a single shot.

Thinking about getting a STB was well.

LiquidBlue

I'm catching up on all the acronyms, is STB a steer bump kit? I am not seeing them mentioned much around this board. Either people don't care, or its not an issue. The few who have mentioned them are not happy with what is out there and seem to be fabricating their own.

Thirdgen89GTA

iTrader: (5)

Strut Tower Brace.

The thing with bump steer is most can't run it because of rim clearance, and lack of any real measurement since every car is different.

LiquidBlue

Thanks, I have ran across the clearance issues. STB Ah! I haven't studied those yet.

What made you decide on the Vogtland springs. I'm leaning that way as well. My springs are actually fine, but I'd like to drop the car a bit for looks. I'm also leaning towards Koni for shocks/struts - and am a bit confused on how some people are running 4th Gen in back so they can adjust more easily. If this is possible, why isn't everyone?

Thirdgen89GTA

iTrader: (5)

The Vogtland were the only non-progressive lowering springs I could find. And the rates were about what i wanted. So thats why I bought them. I don't like progressive rates.

Due to various weight loss on the car my stock alignment has moved into positive camber territory at rest. And I have further weight loss to go as well as weight relocation. So once its all in, together, and settled I'll take a look at cutting the coils to fix the ride height, but only after it settles.

LiquidBlue

The guys I called yesterday all had non-progressive up front, just not back. If you're willing to cut, it looks like you could get Moogs and save a few bucks. The concerns I read on cutting the Vogtlands is they may fall out when car in air.

Have you decided on struts and shocks?

Thirdgen89GTA

iTrader: (5)

I'm happy with the KYB's I put on the car a decade ago when I was much poorer. Perhaps one day I'll go with the Koni Yellows.

Reid Fleming

iTrader: (2)

Hey guys, I got a PM from LiquidBlue on this. I might as well chime in.

I'm still running the setup as described above. I've added other suspension pieces over the years since then and thought about updating the thread with thoughts on them. But maybe I'll start another thread and go into details on ride quality, how they work etc.

I'm a big fan of the Koni/Moog combo because I feel that it solves many issues without sacrificing anything in the process. Probably about 80% of the suspension performance comes from the struts and shocks. The other 20% comes from all the other pieces added up together. So in that regard I find that Koni represent the best performance to value. I don't think lowering springs are worth it from a performance standpoint. Lowering springs are really only for looks.

While it is true that the high end handling cars of today (Z06, 5th gen Z/28, Porsche GT3, etc) are all "low spring" cars. The fact is that the suspension systems in them start with great shocks. Koni would be the equivalent to us. I was playing around with a new ZL1 Camaro on the drive home a week ago. And I could tell that his car had fast reacting suspension. But getting back to lowering springs. The problems I see with them are:

1) They cost more money than Moog.
2) That money would be much better spent towards struts and shocks.
3) These cars are low enough that crummy roads, steep driveways, speed bumps all need to be taken with care. Putting lowering springs on a car just makes this worse. It's already nerve wracking when you see an old tire tread on the road and no time or room to move out of the way.
4) Ride feel will be better with stock height (Moog) springs.

So with Koni/Moog you get the handling benefits from the Koni while still keeping the car up high and off the bump stops with the Moog.

The difference in rear ride height is 0.75" lower with me sitting in the car by myself (I'm 230 lbs) compared to an empty car. So the rear end may seem tall when you initially put the new rear Moog springs in. But you get used to the height and you gotta remember to subtract the 0.75" when you're actually driving. My car has a very slight rake to it. Nothing dramatic. But it is there. I'm fine with this.

Rear Koni choices......You have the two choices. Either the 3rd gen Monotube shock or the 4th gen Twintube shock. The Monotube shock is a slightly better shock design from an engineering standpoint. But in the real world, I doubt you'd be able to tell a difference. The real difference is that
a) The 3rd gen version is $100 cheaper.
b) The 3rd gen has 0,1,2,3 click adjustments (shock must be removed from car) While the 4th gen has a variable **** adjustment from behind the back seat. (shocks stay on the car)

Here's the kicker though. Adjusting the front end of the car with the **** is handy. But you don't need as much adjustment in the back simply because there isn't as much weight in the back. There's no engine back there. So having the 3rd gen rear with the 0,1,2,3 click choices suffices just fine.

I've since added subframe connectors, delsphere LCA, delsphere PHB, Topdown Solutions sway bar bushings and sway bar brackets to the rear end. At this point, I could finish off the rear suspension by changing the rear Konis from 0 clicks to 1 click (1 click = +20% rebound adjustment). But you know what? I'm really not in any hurry to do this.


In terms of strut tower braces. I think they're overrated and annoying. Annoying because they always get in the way when you need to turn a wrench under the hood. My SuperRam is already enough of a pain in the butt to work around. The 2 point STB are OK. But the 3 point STB would be the one to get. The 2 point are fine for side to side motion. But the 3 point help in side to side and front to back motion. Think about accelerating while turning or braking while turning. You're getting a diagonal motion going on here. The 3 point takes care of that while the 2 point doesn't.....But then the 3 point is just that much more annoying to work around. Even putting a charging hose on the A/C ports, you need a 90° elbow to clear a 3 point.

I don't run a STB.

I prefer solid bearing strut mounts instead of strut tower braces. For starters there is no annoying aspect of anything getting in the way. The solid bearing mounts also provide a strong foundation for the STB to function. Adding a STB alone means that the car can still transition side to side and front to back from the stock rubber strut mounts. Replacing the strut mounts with solid bearing strut mounts gets rid of this.

The solid bearing mounts also allow the Konis to function better since 100% of the strut's movement will be determined by the strut itself. The stock rubber setup is going to absorb some of the Koni's movement and thus take away from some of the strut's ability to dampen based on road conditions.

If you imagine connecting two pieces of jello with a toothpick, you get the idea. The toothpick is the STB. The jello is the stock rubber strut mounts.

Getting back to rear springs. 5665 vs CC-635.......The 5665 will work for your car just fine. I too have noticed that the CC-635 seems to be the only one listed in catalogs. They probably just sell more of them. Probably a universal size for many other vehicles. I like the 5665. If I had a couple subwoofers and amplifiers in the trunk, I'd have gone with the CC-635. But my trunk is just the normal from the factory look.

Norm Peterson

5) It is reasonable to assume that the best portion of the suspension geometry is matched to the OE ride height. Small amounts of lowering won't matter much, but the further you go the faster things deteriorate, and the more you're crutching them with spring stiffness instead of using that stiffness to improve anything. For all those appearance people the concept of lowering too far simply doesn't exist, and "stance" counts for far more than lap times, so it's not hard to guess what the spring suppliers are going to produce . . .


Good call here. Actually, if I was to design a STB and had the underhood room and full design freedom I'd make it a 4-point, tying to the cowl area near the base of each A-pillar. Look at the cross-bracing under the sheet metal of a racing Porsche 911.

I had a SuperRam on a previous car (1979 Malibu), and even in that car it took up a lot of room, limiting the effectiveness of any sort of STB structure that you might be able to fit over it. Can't hardly go around it.


I like this analogy! Mind if I borrow it from time to time?


FWIW . . . at one time I was considering dual-rate springs for my current car (hey - it's got a MacStrut up front and the axle is mainly located by LCAs and a PHB, so it's not all that much different from a 3rd gen). Anyway, I didn't like the amount of lowering (way too much) and the deal-breaker came when nobody could guarantee that I wouldn't be hopping in and out of the soft stiffness range during extreme cornering and/or braking.


Norm

LiquidBlue

Thanks for the replies Reid and Norm!

LiquidBlue

Ordered the Konis today. Half my tools are still in storage in Houston so not sure how far I will get until I burn 2 days to move all to A-town. Will try to post progress. Thanks for all the help guys!

BOTTLEDZ28

iTrader: (9)

Wow. some great info here. Im in the market for a new strut/shock and spring setup for a 50K mile bone stock Z28. Just something to make the car feel better during my weekend cruises down the back roads. I will be using 17" wheels and this Koni/Moog combo has my full attention.
Do any of you that are running this combo have side shot pics of your rides so I can see what the fender gap looks like? I dont want to be riding around looking like a lifted truck and I dont want to have that Sportline spring stance either.

Also, I have a chance to pick up a pair of new NOS Koni reds for the front. Is it worth going that route with the yellows for the rear of are the new yellows all around sufficient for weekend driving?

LiquidBlue

All stock here with w6s springs. ~60k miles on them. New Konis yellows. Best photo I could find. 16" stock rims. Honestly don't mind the gap. No pun intended to our English brothers

SirReveller

iTrader: (4)

Drew

iTrader: (58)

If AC Delco still makes springs for thirdgens I'd be extremely surprised. You can almost count on "AC Delco" springs being Moog springs in a box with a different label stuck to it.

SirReveller

iTrader: (4)