I will probably be posting some random question on different boards about my project car and instead of trying to explain all of the details, I will just reference my initial thread that would give more details.
https://www.thirdgen.org/forums/hist...ml#post6548906

I will give an update of where I at with what parts I'm re-using or replacing. Back in 2000 I bought rectangular boxed lower control arms and a non-adjustable panhard rod, along with Eibach 1" lowering springs. The panhard rod I modified to be adjustable off-car (you had to unbolt one end to adjust). Fast forward to today, after spending much time reading about lowering spring opinions (they're kind of all over the map) for the way I will use the car, and I decided to put the stock springs back in. The car only has~50k miles and was supposedly garage kept and wasn't driven in winter by previous owners, then sat in my heated garage since 2000. Rubber components like spring isolators, and bump stops are in good condition, no signs of deterioration. I was going to try to keep this as stock as possible, but unfortunately, I got rid of the original lower control arms and panhard rod. The lower control arms that were supposedly by Edelbrock (I bought the Eibach springs, LCA and panhard rod used). seemed to bulky and heavy, and the panhard rod wasn't welded perfectly concentric, I decided to by all new matching components. By far Founders Performance which seems to make decent stuff, was the cheapest, so I bought black LCA's, adjustable on car panhard rod and adjustable torque arm for ~$470 for everything. I also forgot until I inspected 91z28 10-bolt I am installing; I had lower control arm relocation brackets from Spohn already welded on. I figured the black 1-1/4' components will blend in under car better than the obvious red ones and provide better performance than the stock components.

So this is where my question comes in about shocks and struts. I read a lot about this also, and concluded I didn't want expensive road racing shocks and struts like the Bilstein or Koni because I'm more concerned about the ride quality. I have looked at the KYB G2 from Rock Auto, a full set of shocks and struts are ~$150, or ACDelco Gold set is ~$200. These new struts/shocks seem inexpensive and begs the question, is the stock Bilstein struts/shocks that came on my Iroc, even with 50k miles, better and still have life left in them, or should I just replace them now?

That's the only question for now, I can't install the axle yet as I'm waiting for the new Founders Performance parts. Let me know if I'm missing or forgetting anything.


91 Z28 10-bolt, stock shocks, rectangular LCA's

Stock and Eibach springs

 

your Bilsteins can be rebuilt, I would go that route.. I've had good luck with KYB on Toyotas. The koni adjustable on lowest setting provides a nice ride, close to factory.

 

For stock springs, with the intent of a stock ride, I would have NO problems with AC Delco. I have also had positive experiences with the non adjustable KYB's. In my experience, Koni Yellow, even on the softest setting is not soft enough if stock/comfort is the goal. JM2C. I'm hoping to do a stock ride quality rebuild of my 86 Z and plan to use KYB.

 

Thanks for the input. I heard the Bilstein shocks had a lifetime warranty and were rebuildable, so I went to their website and found the warranty was only for the original owner. I don't want to spend the money for new Bilstein or Koni struts/shocks, but that brings me back to my main question, do people think the stock shocks are worn out by 50k miles. Were the stock shocks actually better than a new KYB non-adjustable or ACDelco replacements? There is a couple of Bilstein retail/repair places close to me so I may look at what it cost to rebuild the stock shocks if they are rebuildable. Another question would be does anyone know for sure who made the stock front struts on the IrocZ? I can't get under the car enough to look for a manufacturers label on the front struts, but I'm pretty sure they are stock, but they aren't yellow like the Bilstein labeled shocks in the back, they are black. Currently Bilstein doesn't offer any struts for the 3rd Gen cars, so I wonder if they ever did. Here's a link to the ACDelco Gold through RockAuto: ACDelco Strut, and the rear shock: ACDelco shock . Rock Auto Listing under strut/shocks for 1988 Iroc: RockAuto 88 Iroc 5.7l suspension . If rebuilding shocks is out of the question, and 50k miles is at the limit of their serviceable use, I will buy one of the 2 sets listed.

 

Your Bilstein shocks/struts may or may not be good after all these years I would guess probably not. Those are really nice shocks, it may be worth while looking into getting those rebuilt. With stock springs You could run any of the other shocks/struts that you mentioned. Your choice of shocks/struts would be a lot ore critical if you were going to run lower springs that are stiffer than stock.

I have Koni Yellow shocks/struts springs on my Z28 and they are fantastic. Great for handling and makes the car feel much more in control especially during hard cornering and/or bumps. I would say they feel slightly firmer than stock shocks/struts but offer a lot better control. These would be the ultimate choice but definitely not needed in most cases for a street cruiser.

I have the adjustable KYB AGX shocks/struts on my RS Camaro and they are fine. Not in the same league as the Koni's but get the job done at a lower price. I haven't tried the G2 KYBs but I've heard good things about them. I wouldn't hesitate to use them on a stock or street cruiser application. KYB makes decent parts for a reasonable price. Probably not the best option for a serious performance application but work great for a street cruiser.

 

If AC Delco shocks are coming up in the same conversation with the Koni Yellows, then we're not all on the same page here. That being said, I've got experience with both, and while the Koni's were amazing, in my opinion they are WAY overpriced and still a little too firm for a stock-like application. Great shocks, but not for this application (I think). The AC Delco shocks, along with stock springs and suspension parts will provide a comfortable and sporty ride, and should last several years. A friend of mine recently let me drive his 86 sport coupe that he had swapped in a complete, stock IROC suspension with OE replacement MOOG springs (don't know the PN#) and the non adjustable KYBs on all four corners and the ride was great for a street car with no intent of serving any track duty. It'll likely be what I use on my 86 Z build next spring.

 

I just decided to buy new struts & shocks since I can't get the struts off now because the cars jacked up with no rearend in it. I'll save the Bilstein shocks/struts to see if I want to rebuild them later. I was leaning toward the ACDelco thinking they were OEM parts, but I was searching on this forum and other forums and people were complaining the ACDelco Gold was junk and made in China. I probably spent too much time just because I thought GM replacements would be the best. Eventually I went to a Genuine GM Parts website and found that GM has 3 tiers and uses color on packaging to differentiate parts. Blue is OEM GM manufactured parts, Gold is second best then Silver, both are considered GM certified aftermarket parts. GMPartsExplanation. Not all websites give you a total explanation and you don't see the packaging colors. I think I looked for OEM replacements at, Napa, RockAuto, Summit Racing and on Amazon, and they were either Gold or Silver. One of those showed origin of manufacturer as being China. The other thing I noticed was a big discrepancy on prices for the same part# ACDelco which made me think some of those could be counterfeit parts.
Another Link about GM Parts: ChevroletForum. If interested click on the #2 post in the previous link, more examples differences.

I just decided I wasn't wasting anymore time and bought the non-adjustable KYB OE equivalent shocks/struts since there seems to be a lot of people that are happy with them compared to the original equipment.

 

clicked to many times and duplicated

 

I think you'll be happy with the KYB's.