Bailey28

Guys,

I want to replace the original shocks on my '94 Z28 convertible. Currently the car has the original Decarbon's on it. I have been shopping for a replacement shock, and found two different front shock part numbers that supposedly fit my car:

AC Delco 530-114 front shock- about $70 online

AC Delco 540-27 front shock - about $125 online

What is the difference between these two parts? I have seen both part numbers spec'd on different microfische sites.

For the rear I believe the 530-10 is correct.

All of these are black in color.

I don't plan on racing or auto crossing the car, and I want to keep it all AC Delco if I can help it.

Thanks!

99Bluz28

iTrader: (35)

AC Delco 530-114

ACDelco Premium Gas-Charged Shocks and Struts With RoadResponse™• Special motion-sensing valving, which helps respond to changing road conditions, provide a more comfortable ride during normal road conditions and improve handling under extreme road conditions
• Speed-sensitive damping automatically adjusts for improved performance throughout the entire range of motion.
The 530-114 has valving that changes as your driving. Sounds like a Monroe Sensa-trac shock to me.


•AC Delco 540-27

Premium Monotube shock, the Monotube will offer better control especially on less than perfect roads.
IMO for what the AC-Delco monotube shocks cost, I'd highly recommend getting a set of Bilsteins monotubes instead for almost the same price.
http://www.ws6project.com/user_stor/...age-set-of-4-/

Bailey28

Thanks for pointing me in the right direction. It sounds like I want a monotube shock from what I've been reading.

Twin tube shocks sound like they should be installed on grandma's wagon.

Are the stock Decarbon's a monotube or twin tube design?

Flaring Afro

Why do they have to be that brand? You'd be much better off with Bilsteins, and they're cheaper. Better handling, better comfort, probably longer lasting.

http://www.ws6project.com/user_stor/...age-set-of-4-/

Edit: 99Bluz28 beat me to the punch.

Bailey28

This car is all stock. I want to stay stock unless there is a real good reason for going with something from the aftermarket.

I have been around the block a few times with different cars and I, personally, find that nothing fits, performs, and lasts like OEM parts do. I make this statement not in disagreement with you all, but out of personal experience of buying thousands of dollars in parts that lasted a quarter mile at a time on previous builds.

I could care less about superchargers, big camshafts, head porting, 4.56 gears, lowering springs, compression adjustable shocks, ladder bars, etc... I'm not 19 anymore and don't care about stickers, drag radials, subfame connectors, flowmasters, nitrous, and most of the Jegs and Summit catalog offerings. I've been there, gone fast, broke stuff, spent even more money, broke it again, etc.

Let the aftermarket be for those who wish to alter, sometimes permanently, their vehicles with no or little regard for it's future value and/or safety. I will agree that very few of the aftermarket products are actually quality parts with longevity, fitment, and value in mind.

I do care about maintaining the original oem appearance, ride, and handling of the vehicle I own.

Bilsteins: $367 for all 4

AC Delco 540-27(2) and 530-10 (2) $290 for all 4 shipped

AC Delco 530-114 (2) and 530-10 (2) $ 194 for all 4 shipped

How are the Bilstein's cheaper?

Flaring Afro, I hope this answered your question about "why" they need to be this brand. I cannot find or buy brand new Decarbons. The factory replacement stuff is what I am focusing on. Yes I agree Bilstein is a good brand and was even offered on some GM stuff previously.

Bailey28

Let me sum up me: There are two kinds of guys, they guy who needs to replace the fuel pump in his F-body and cuts a hole in the trunk area. Then the other guy is the one who drops the exhaust, axle and tank to avoid cutting a hole in his car.

I am the second guy, who just this past weekend, spend two days on installing a new fuel pump my way (no hole). Oh, and the gasket they sent the first time was junk. Spectra junk, didn't fit the 3 3/4" hole in the tank. I had to get the AC Delco tank to pump gasket, OEM part that fit the right way.

Flaring Afro

Shocks fit in without any kind of modification. The stock shocks are complete crap. You can have a better ride, handling... everything with Bilsteins. The only reason to not want them over stock shocks is if you are trying to keep the resell value high of a classic car in a long time from now - but if you're driving it enough for the old shocks to go then it won't be worth anything. There are no reliability or fitment issues like with other kinds of modifications. The only "complicated" thing about bilsteins is you have to take the perch off the front shocks and slide it onto the bilsteins, which is a piece of cake. If that bothers you, there are other all around better shocks out there that do come with their own perch. Buying oem shocks for fitment reasons is like buying oem tires instead of other brand and models of the same size. There's a big difference between that and a hood or some cheap part made by a company whose only concern is to make a claim that it fits well enough and to make it as cheaply as possible.

Also, the prices you listed were next to the singular word shock so it looked like they were a lot more expensive, but I still wouldn't ever pay for more crap shocks. You mentioned safety and the car would be a lot safer with better shocks that help you keep control.

Bailey28

We all know that Bilstein makes quality components. I am still wary of investing that king of money into a shock in which I have no real comparison of how it will ride in the end.

In other words, I don't want it to ride like a skateboard, with a harsh and jarring ride. I don't want it so loose that it handles like a shopping cart full of bowling ***** going down a staircase either...

I am very familiar with suspension system internal valving as I am able to change the internal shim stacks on a motorcycle. We know that valving is what gives shocks a certain "feel" via compression and rebound characteristics.

From the above post, it sounds like the Delco 530-114 has the Monroe sensa-trac valving, probably soft when in the initial part of the travel then it stiffens up in the later parts of travel, like "progressive" valving.

I was looking for more of a "digressive" type valving, where the shock is slightly stiffer at low shaft velocities for good cornering and braking, but then "blows off" when a larger square edge hit is encountered in order not to upset the car.

I know on a motorcycle that going softer for comfort will eventually make it harsher, as it will be too soft, ride down in the stroke, and wallow.


All in all, I was curious as to how the Decarbons compare to the Bilsteins, compare to KYB Gas a just, compare to the AC Delco's.

BMR Tech2

iTrader: (5)

Another vote for Bilsteins here. They are one of the cheapest and most noticeable differences you can make as far as ride quality and handling on your F-body. If you are replacing your shocks anyways, why not upgrade for roughly the same price?

Flaring Afro

Also, people often buy KYBs and aren't satisfied with the ride quality and handling - even with stock springs. People only don't like Bilsteins if they wanted a race car setup or if they expected to get a rolls royce ride just from getting some shocks.

People tend to recommend Bilsteins for comfort and koni single adjustables for handling. Those are the 2 best options that are readily available and don't have extreme price tags.

demonspeed

iTrader: (7)

I'm supporting the ACDelco route only because I respect Baily28's position and will be there myself with the next f-body purchase I make (not replacing the current -- an additional "stock" example). I think he detailed quite diplomatically why he wants to stick with OEM. While DeCarbons are not available, ACDelco will be the next equivalent.

Anyway, the ACDelco "OE" part number is 540-27 for the front which is why it's so much more money. Their Professional line (essentially the "matches or exceeds OE specs" aftermarket version) is 530-114. If you want to stick as stock as possible, you'll want 540-27. Period. The rear, however, does not appear to offer anything but the Professional 530-10 shock.

You'll likely want to consider new strut mounts and rubber isolators/bushings as I'd imagine the stock ones are junk and you might have near impossibility removing them from the strut due to rust/seizing.

edit: If you wanted to go with a Bilstein yet remain as OE as possible, you can pick up a set of SLP Bilsteins as they'd be the closest equivalent to Y2Y "Bilstein suspension package" optioned SS/Firehawks. Of course, this would not be something that was available in 1994, but it's just something to keep in mind should the "experts" brainwash you.

edit 2: GM part number is 22199128 for the front (according GMPartsDirect)

Another option would be Koni adjustables as those came on the 1LE Z28 in '94:

Flaring Afro

Bilstein made changes to their regular shocks for us and there isn't a difference between the slp and hds anymore, unless you just want the slp name on it.

demonspeed

iTrader: (7)

They don't even have SLP anywhere on them It's just the peace of mind knowing one purchased something "OE" ordering the SLP number (and when I bought them, SLP was cheaper than the non-SLP branded Bilsteins!).

99Bluz28

iTrader: (35)

They're Monotubes. BTW, the AC Delco shocks I priced at almost the same as the Bilsteins was the AC Delco 540-27 front Monotubes, and the AC Delco 5405001(#88962978) rears Monotube shocks. Not with the rear AC Delco 53010 shocks.

01WS6/tamu

iTrader: (37)

If this is a car you are going to drive and enjoy put bilsteins on it. No matter how you stack it stock decarbon/acdelco are trash. If the car has 55 miles on it and is going to be polished and stared at and not driven then put delco shocks on it. But if you are doing it from a future collectability point of view don't bother it's not like these cars are first gen z28's. WS6 store has one of the best prices around on the bilstein's and they are a sponsor here.

Flaring Afro

I do want to point out that I do understand wanting to keep a stock appearance, and understand that a lot of things (especially body parts) don't fit as well if not oem. My car actually has a factory look to people that don't know much about the car - the springs I ordered make the car's wheel gap similar to current sporty cars off the factory line and don't make it look slammed, and most of my friends (many of who think sport cars are cool, but none are obsessive car people) didn't realize I changed the exhaust since it's honestly not that loud since I have oem manifolds, cats, etc (and I kept the stock exhaust to sell with the car if need be). I don't like the clearly modified look of new bumpers or 19" wheels etc. I also care about reliability as this is my only car and I'm in college and can't afford to replace the engine.

But there is a reason why slp deemed it necessary to put bilsteins in their firehawks, and a reason why I chose Bilsteins when my rear shocks blew (which I decided before I started to think about lowering springs).

Bailey28

Thank you guys for all of your valuable input.

99Bluez28- OK, now I see how you came to the pricing.

Flaring Afro- Are there different spec Bilsteins for our cars? I like the idea of comfort more so than "hard".

I do like the idea of having the mototube shocks for better handling. Nothing would disappoint me more than buying a crappy handling shock, be it OEM or aftermarket.

I will investigate the spring cups and related parts further to see if I need replacements. I am glad to be able to work on my car and perform pretty much anything that needs to get done.

This is a weekend pleasure driver. Top down, kid in the back, wife in the front to and from local car shows, meets, ice cream store, cruising, etc.

Flaring Afro

I'm installing mine this weekend so I can let you know how they are from experience after that if you'd like, though the springs will make it somewhat harsher than it would be for you. Also, I've heard there can be a break in period for the shocks. But here's some quotes from a couple of threads. If you search "most comfortable shocks" or "best daily driver shocks", you can find even more testimonies. Just keep in mind that, as said earlier, there are older Bilstein HDs that didn't have as good valving as the new ones which basically are the old SLP versions (possibly EXACTLY the same?).


And a quote comparing koni's to bilsteins. Note that there are new, cheaper konis being made (though always on backorder by months) and this is talking about the $900 "single adjustable" set.
I personally wouldn't expect miracles with these over stock shocks on a fairly smooth road, but if you have to deal with potholes, etc you will feel the shocks doing their job much better, and the car won't feel nearly as sloppy when going around turns.

libertyforall1776

iTrader: (2)

Bilsteins and Konis both have a lifetime warranty, so worry-not.

To be fair the AC Delco shocks may have improved in the 12 years + that the F-Body has been out of production -- I am not sure many would know or have tried them?

demonspeed

iTrader: (7)

FWIW, I did not really notice any difference when I replaced my 65k mile DeCarbons/stock springs with the SLP Bilstein/Eibach combo. If you're considering going the Bilstein route, I wouldn't worry at all about harshness.