777Shock777

iTrader: (1)

Hey everyone, I have an 88 GTA that I've owned for many years, but I'm trying to really improve the ride on this thing. If you hit a bump/manhole cover it feels pretty sharp and the whole frame seems to rattle from it.
My 99 WS6 with similar mods rides so much "tighter" and doesn't rattle the frame or your body nearly as bad.

I've tried to keep it as a cruiser with some mild improvements: BMR lowering springs (1/2" spacer in rear), KYB AGX shocks/struts (turned up to higher levels to compensate for lower ride), Subframe connectors, wonder bar, and all new rubber bushings for the LCAs, panhard bar, etc.
Maybe I'm running too harsh of springs? I like the mildly lowered look and maybe switching to Hotchkiss or Summit springs with softer spring rates is what I need.

I'm going to be changing the old Kumho tires in a month or so as well, I just wanted to see if anyone else has any advice I can add to that.

//<86TA>\\

iTrader: (14)

Turn the shocks down and what happens? Fwiw, I have much heavier springs than you and use koni yellows on 18" wheels. Ride is wonderful.

QwkTrip

iTrader: (22)

Ride quality is mostly about shocks. Expensive shocks.

Also, lowering a car changes the working length of the shocks. Need shocks designed to work at that length for best results.

777Shock777

iTrader: (1)

If I turn down the shocks to the softer settings there is no dampening and the ride is horrible. My understanding is these AGX shocks were designed for factory height.
Koni Yellows huh? Are you lower than stock?

777Shock777

iTrader: (1)

Do you have any shocks you can recommend? I have Bilsteins on my 99 but I saw that Bilstein doesn't make shocks for our cars anymore?

obeymybird

iTrader: (4)

The BMR spring rates are 620/160 these are really good numbers for a fun street car. The problem as already pointed out is the lack of koni yellows front and rear set the rears to 0 and start at a half turn on the fronts and adjust to your sweet spot.

Im on yellows as well with 850/200 rates and ride is very good also on 18x10 wheels front and back.

777Shock777

iTrader: (1)

Sounds like that's my issue for sure lol, any recommendations on the best vendor to purchase these from? I thought I remembered hearing about a group purchase this time of year, maybe not.

Sweet! I think 18's on the 3rd & 4th gen look perfect, if I wasn't going for an oe+ style build I would definitely do that.

TEDSgrad

iTrader: (4)

Yes, shocks as mentioned.
Also, the strut towers have a bushing that can be sloppy. The fenders are not all that sturdy. Good idea to have a strut tower brace or 3 pt to cowl if you can find one. This keeps the shock firmly in place and forces it to do it's job without movement.
I added a plate underneath for more security and force distribution. Spohn sells it with coil-overs, which is a bad idea, but the plate is not a bad idea.

Reddragon88gta

Just throwing this out there , I run my car strictly on the street as a cruiser/weekends/ occasional daily driver and have KYB excel g’s on factory springs. With SFCs, LCAs, wonder bar, poly end links with panhard bar and the car rides good and comfortable IMO.

obeymybird

iTrader: (4)

777 car doesn't have factory springs.

777Shock777

iTrader: (1)

I just ordered a set of Koni Yellows, looks like they are all on sale right now so good timing I guess lol. I went with 3rd gen rears over 4th gen for the monotube design.
Nice! I'll have to look into those plates, I originally had purchased a strut tower but didn't want to drill into the strut, maybe I should reconsider and look at all the options again.

777Shock777

iTrader: (1)

I remember the factory ride was pretty nice, I just like having a slightly lowered appearance

LiquidBlue

I had same problem you mention until I turned my yellow konis down to softest setting. All factory suspension. Some subframe connectors would probably go a long way in getting all of those shocks and spring you got going there to work in unison.

777Shock777

iTrader: (1)

I do have UMI Subframe connectors currently installed, I'm hoping once I get the Koni Yellows installed next week it will ride smooth!

777Shock777

iTrader: (1)

The rears came in over the weekend and I'm impressed, even just with rear Koni Yellows the ride is so much better!
The fronts should be arriving tomorrow.

777Shock777

iTrader: (1)

Installed the Koni Yellows on the front, as everyone suggested! - Night and day from when I made this post a week ago.

I updated the title, if anyone stumbles across this thread, spend the extra $ on Koni Yellows, especially if you are lowered!
Thanks everyone, I'm happy with my 88 again

DaveyDug

iTrader: (3)

Good call, OP. When "Thirdgen Ride Quality" is the question, "Koni Yellow" is usually the answer.

obeymybird

iTrader: (4)

Awesome! Thanks for the update.

soulbounder

Good to hear. Where did you order the Koni yellows from?

//<86TA>\\

iTrader: (14)

Awsome news!

777Shock777

iTrader: (1)

Thanks again everyone, hopefully this thread will help others in the future too.
As far as settings go, they are both set to full soft. I'm going to slowly turn them more firm each drive so I can find the spot that I like. Utah has some pretty rough roads at times so full soft may be where I leave it anyways.

Amazon had the fronts the cheapest ($231 each) and Summit had the rears the cheapest ($109 each) as of last week when I ordered them.

1985_IROC

Glad to find this thread, and thanks for the feedback on the Koni yellows...I've been holding off while trying to get a few other things done. Maybe time for me to pull the trigger while they are on sale.

777Shock777

iTrader: (1)

Not sure what springs you are running, but honestly you could probably run Koni in the front and the Excel-Gs in the back and still have a pretty good ride.
My rear Koni's arrived before the fronts, so for a few days I drove around with only Koni's in the rear and it still drove so much better.

Yeah I wish I had just bought these Koni's the first time around instead of messing with the KYB AGX's first, I say go for it!

777Shock777

iTrader: (1)

The Excel-G's should be fine for the stock rear springs. Fronts however, yeah especially with poly a-arm bushings you'll feel a lot more road noise. Could probably go with the Koni fronts to really help offset that.

TEDSgrad

iTrader: (4)

Utah is a great place to roll on the Koni's.

McLovin1181

This is honestly why I never Recommend KYB Shocks or struts.
they don't have enough rebound or compression forces for even Stock rate springs for even the V6 cars.
Quality shocks ride pretty well, even if you run insane spring rates like me.(1200lb front, 400lb rear)

Pic is a shock dyno Plot of the 3rd gen rear Koni Yellow.

91z28 98ta

iTrader: (1)

Im a firm believer in good shocks ive had many thirdgens .. after lowering mine it rode like a wagon..after i put yellow koni’s on, its so smooth and comfortable . these shocks are sweet and the best option if its in your budget.

1986BANDIT

i just put koni yellows on the front of my t/a and its fun to drive again.that being said i lowered it about two years ago and ran with the stock struts.
when i pulled them out and compressed them,they stayed that way so they were literally doing NOTHING..IVE GOTTA GET REARS NOW!!!

sucks that they were $700 a pair in Canada (or $450 usd lol) and that was by far the cheapest i could find them,easily $120 cheaper than summit

IROCThe5.7L

What setting is everyone running on their Koni's?

1985_IROC

I am going to order my Koni yellows, and will set them on softest (lowest) settings.
Also plan to purchase ACDelco springs vs. Moog;
Rear: ADO-45H3025 - ACDelco Professional Coil Springs (these are the Moog CC635)
Front: ADO-45H0154 - ACDelco Professional Coil Springs (these are the Moog 5662)
Good setup for around the town driving?

clubber

iTrader: (1)

I've got your spring setup, although the moogs, and koni's. The street handling and ride are excellent. The best ride vs handling compromise of any car I've had. I would recommend this combination to anyone who doesn't want a lowered car. I believe that the Koni's would work fine on lowering springs too but it's just a guess as, like I said, I'm not lowered.

1985_IROC

Thanks Clubber!
And I was leaning toward the ACDelco's simply because the price point is a tad bit lower than the Moog's.
There are so many threads on spring/shock setups...and trying to interpret the stock build codes are just as confusing.
Came across one that thought to help, as I have the FE2 option, but it didn't have the correct information to my build sheet.
From my build sheet I have, FE2 but with ZW|ZW and NN|NN, which is different than the following.

Following from @Drew post a looong time ago...sorry to at you Drew. Just trying to interpret...
6ZX : SPRING, COMPUTER SELECTED, FRONT, LEFT HAND 85 Iroc FE2
7ZX : SPRING, COMPUTER SELECTED, FRONT, RIGHT HAND 85 Iroc FE2
8NL : SPRING, COMPUTER SELECTED, REAR, LEFT HAND 85 Iroc FE2
9NL : SPRING, COMPUTER SELECTED, REAR, RIGHT HAND 85 Iroc FE2

In any event, will go with what everyone else is doing for stock ride height.

Drew

iTrader: (58)

What are you asking?

GM spring codes are coded differently depending on where you find the code. On the SPID, the first digit tells you the location (corner) of the spring in question. The actual spring code will replace that first number with the letter. But I'm guessing that's not where the confusion lies...

If you're wondering why two cars of the same year and same suspension package can have different springs, it's because the springs are selected based on a computer algorithm and they have a range of springs that can be selected within a suspension package. Usually that range of springs is about 3 springs wide. They're close enough you'll often see a different spring on the left and right of the same car.

An FE2 car could have CDB, BZW, or BZX springs in front, and NNM, NNN, or NNL springs in back, it all depends on how the car was equipped and what the "computer" felt was the best match.

Unfortunately when you start dealing with replacement parts, you're never going to match exactly what the factory used. Everything currently available is a one-size-fits-all solution that fits everything equally poorly.

1985_IROC

So where does everyone order Koni shocks from?

obeymybird

iTrader: (4)

I might have some low mileage rears for sale soon pm if your interested.

1985_IROC

Hey guys!

Got the rear Koni’s installed this weekend, and WOW, totally awesome ride. Can’t wait to get the front struts done.

Have to say best upgrade so far...👍🏼

(Keeping the original springs as advised by Sam Strano). If anyone is still looking to purchase, I ordered them from him on Friday ~4pm and they were on my doorstep the next day at 12pm.

Reddragon88gta

I kept my original rear springs when I did my rear shocks and should’ve just changed the springs at the same time. After swapping out the originals this spring for new AC Delcos the rear suspension feels much better and you really notice it over the bumps, it is more composed. The originals could be removed without even removing the bottom shock absorber bolts and this was an 80k mile car.

The new springs also didn’t change stock ride height as much as I originally feared which is why I was hesitant to swap them before. Ride height is almost the same as before, likely what it was when new.

1985_IROC

I'm stepping through this process one step at a time, have same fears as you did. Appreciate the push (advice) to get the springs, will end up doing so eventually, just a matter of time. (btw I measure 27.25" at the rear with half tank of fuel)

1985_IROC

I’m installing the rear springs, Moog CC635, want to see if this improves the ride or not. Assume that ‘indexing the coil’ means putting the end of the top coil properly on the insulator and this allows to seat evenly on the body of the car, correct?

777Shock777

iTrader: (1)

For my 88 I ended up putting some 4th gen springs/isolators from a 98 SS. I like it being a bit factory looking, but it was definitely an improvement over the BMR lowering springs I had.

I believe for the rears it doesn't matter which way they are facing as long as either the isolator you are using is properly installed.
The front you have to index by the bottom coil being between the 2 side by side holes in the A-Arm.

1985_IROC

Update; car feels really good with the rear springs and all Koni yellows set to one full rotation off softest. New inner/outer tie rods with the UMI performance adjusters were installed as well. vroom...