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help me choose struts and springs 2001 Grand Prix GTP

L

Lifespeed

New member
I've done some suspension (and other) work on this car, but the tires are wearing badly. All 4 tie rods, sway bars (large GPP models) and end links have been replaced within the past 10K miles. Struts are the Koni red adjustable inserts that required re-using and modifying the old strut body, but they have more than 80K miles on them and don't damp as well as they should. Also the control arms, bushings and ball joints no doubt are shot. I'm taking it to a suspension shop that I trust on Monday, but am pretty much assuming these old components are going to need replacing.

I am planning on going with stock front GM control arms and UMI rear control arms. The ZZP front control arms seem too spendy for this 160K mile daily driver. Unlike some of you, this isn't a cherished car for me. Sorry, just reality.

I guess it comes down to which struts and springs should I get? I know how important these are. Unfortunately, I'm not sure if I can practically do the Koni red insert thing again using the old strut body. I think welding the body to the insert was part of the process, and may be a one-time thing. Of course the old springs are worn also. I don't want to lower the car, the GTP is already low enough. I am also well aware that increasing spring rate without increasing strut damping is a losing proposition, resulting in a harsh, underdamped ride.

Anybody here have some proven results with a good strut/spring combo?
 


Any reason I shouldn't go with GM parts? The struts are kind of spendy, of course. Do they still sell the original parts unique to the GTP? I'm assuming this car originally had stiffer, lower springs and struts. I know sometimes the mfg's cheap out and just sell one model of spring/strut for the entire W-body line when the cars get old. Don't want to waste my money on factory parts only to get a generic W-body combo.
 
Anybody? Does the GTP have FE1, 2, 3 or 4 suspension package, or is that just the later models that offer those options? Does the GTP have different suspension tuning the base model Grand Prix? Are the GTP-tuned shocks still available from GM, and are they better than, say, KYB AGX? What about springs; still available in GTP tuning from GM, or get Eibach 1" lowering springs? There are a myriad of options here, trying to choose the right one. Reading through the forums I have already learned about the Moog ball joint replacement for the factory front LCA rear bushing in this post. So I'll be buying some AC Delco front LCA and have the suspension shop press in the upgraded Moog bushing.

At the moment I am leaning towards KYB AGX struts, but am uncertain about which springs to get to arrive at stock GTP ride height and firmness. I wonder about spring/strut rate compatibility also, and would like to hear results from people with similar combinations.
 
Dont worry about the ZZP tubular LCAs. I AM a big fan of these cars, but theres no way Im spending that kinda coin. I got Dormans up front, with the Moogs. As far as struts, I don't know about the FE1-2-3 stuff....I got a set of these from AM Auto. They were $200, 2-3 years ago. That's was 50 per wheel, and free shipping. And they weigh a ton. Before I curbed my GTP for repairs, I put about 3000 miles on those suckers. Rode great. Stock ride height. Some bullshyt brand....Laecree or something.

https://www.am-autoparts.com/products/brake-steering-suspension-kits/AM-740055916.html?m=114&y=2000
 
CHI2000GTP said:
Dont worry about the ZZP tubular LCAs. I AM a big fan of these cars, but theres no way Im spending that kinda coin. I got Dormans up front, with the Moogs. As far as struts, I don't know about the FE1-2-3 stuff....I got a set of these from AM Auto. They were $200, 2-3 years ago. That's was 50 per wheel, and free shipping. And they weigh a ton. Before I curbed my GTP for repairs, I put about 3000 miles on those suckers. Rode great. Stock ride height. Some bullshyt brand....Laecree or something.

https://www.am-autoparts.com/products/brake-steering-suspension-kits/AM-740055916.html?m=114&y=2000
Click to expand...

Thanks for the response, there is no way I'm paying for ZZP LCA either. But . . . I do have an aversion to the very cheapest struts. As Carroll Smith said, "Shocks are the brains of your suspension, buy the best you can afford". Now, I have to balance this against the daily beater application. So I'm not going to have Penske custom-build me a set of coilovers like I did for my other car. But I do want to accomplish GTP spring rate, ride height, and a decent quality strut.

Those struts you linked are the expected one-size-fits-all, and so cheap as to be hard to believe they are decent quality. I would like to do a little better, but I do appreciate your input.
 
Lol. No problem. Definitely cheapo depot struts. spazz seems to be the resident suspension expert on here. Maybe you'll get more input.
 


CHI2000GTP said:
Lol. No problem. Definitely cheapo depot struts. spazz seems to be the resident suspension expert on here. Maybe you'll get more input.
Click to expand...

$hit bro, did I tell you I expertly sell reliable used cars for a somewhat great price on Tuesdays too? Honestly, I worship your literal alley mechanic skills.
Anywayz
You know it all depends on what you want to spend Life
The FE3s ( from 04-05 ) are still available and are a good strut. They might be listed under GXPs to.
I did have a problem with the rears on SSCs and went to Bilstein rears.
They (FE3) are reasonably priced for a better strut.

I am no expert just a guy who has read a metric $hit ton of reviews. I new what I wanted and bought it after research.
The CompG I have had FE3s stock before I bought new ones for the SSC lowering springs I bought. I knew what to relatively expect.

The ride ain't no fckin Lincoln or Caddi but it rides tight and my roads are not all that bad, snow or not.

If you are going stock springs just buy the ExcelGs, they do have a fairly good rep. If you are lowering, honestly then it is pretty much a crap shoot on W-bodys.
Hope that helps a little since most guys that like to talk strut damping and progressive/linear spring rates are driving more important vehicles now....geesh
 
Haha. Somewhat great price, eh? Lol.

Your definitely the suspension expert here spazzz. You know your shyt.

And, Thanks! Alley mechanic for real. Didn't know I had it in me. Caught the bug good after doing the LIMs. I'd be up sh1ts Creek without this site tho.
 
spazzz said:
Hope that helps a little since most guys that like to talk strut damping and progressive/linear spring rates are driving more important vehicles now....geesh
Click to expand...

Now you're embarrassing me :th_embarassed:
I do have a "more important" vehicle, a 2004 Mercury Marauder. Got a new engine for it, and supercharger kit. Some assembly required. It's cooling off here now in sunny California, so working in the garage isn't purgatory and hopefully I'll be back to driving a real car soon enough (no offense to my W-body friends).

But my suspension experience prompts me to at least spend money on the right parts. It's going to cost to fix this thing up, I may as well choose the right struts and springs. My son will hopefully be able to drive it through the last couple years of high school and maybe through college.

I don't want to lower the car from stock, although I thought the GTP was lower than the rest of the W-bodies from the factory, BICBW. I am fine with slightly firmer springs, so long as struts with increased damping are available. In know from experience how awful stiffer springs work with stock struts.

Could I impose on you to point me in the right direction as far as year/model crosses, and maybe some part numbers? It sounds like My 2001 can use later model struts (your FE3 example), but this does not seem to be reflected in the online parts catalog. The only non-parts-store shocks I can find are KYB, but you mentioned running Bilsteins, which I have always liked. Are the FE3s an OEM part from GM, all four corners? Would I get the factory springs also? Will they produce the same ride height the GTP has now?

Thanks for you help. Maybe you can spare me a ton of reading. :)
 
For your 2001 you can buy anything from the 97 up catalog..So just shop from the 2005 up Gxp for struts. And yes oem delcos for the FE3
You just missed some guys selling Bilsteins. Otherwise those things, at this point would cost over a grand just for struts.
I have FE3 sport suspension in front with the GXP rear Bilsteins on SSC(Canuck motorsport springs).
I do have my stock springs yet if IIRC they are all the same.

I can look for the part numbers tomorrow as I am in bed and on the phone.
My reasoning also with the car for my son.
 
The GXP is a 5.3L V8. I can't see how the front struts could be used on my 2001 GTP, the spring rate and damping would be too high. The rears would probably be OK. Perhaps that is what you meant by FE3 in the front and GXP Bilstein in the rear.

Here is the parts list for 2005 Grand Prix 5.3L GXP rear suspension.

It looks like:
25853345 Strut GRAND PRIX; RIDE & HANDLING SUSPENSION; W/ SPECIAL SUSPENSION $272.93
is the GXP strut.

88955412 Strut GRAND PRIX; RIDE & HANDLING SUSPENSION; W/ O SPECIAL SUSPENSION $144.81
is the FE3 strut

88955413 Strut GRAND PRIX; SPORT SUSPENSION $155.00
is the base model, not sure if that is FE1 or FE2.

Here is the parts list for 2005 Grand Prix 3.8L GTP front suspension.

88955411 Strut Strut, LEFT W/ SPORT SUSPENSION, W/ O GXP $138.38
is the FE3 strut

88955410 Strut Strut, LEFT W/ O SPORT SUSPENSION $178.25
is the base model, not sure if that is FE1 or FE2.

Is this correct?

Looks like springs aren't available OEM, but shouldn't be a big deal to get aftermarket. It sounds like SSC is a good place to get springs? Typically I prefer linear rate springs, not progressive.
 
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Koni can re-build the inserts for a price. May want to check that out.

One thing I recall reading was that the bilsteins from an GXP actually raise the 97-03's even with stock springs.

If you are going to stay on stock springs just get the KYB's as mentioned. If you would like to lower it just a tad the vogtland/KYB AGX's is a nice combo even for daily driving. My brother has that set up on his 03 and it's pretty close to the GMPP lowering spring and GMPP koni strut combo.
 
The Guz said:
Koni can re-build the inserts for a price. May want to check that out.

One thing I recall reading was that the bilsteins from an GXP actually raise the 97-03's even with stock springs.

If you are going to stay on stock springs just get the KYB's as mentioned. If you would like to lower it just a tad the vogtland/KYB AGX's is a nice combo even for daily driving. My brother has that set up on his 03 and it's pretty close to the GMPP lowering spring and GMPP koni strut combo.
Click to expand...

KYBs may be the route I end up going, but in my experience they are barely a step up from Monroe, Gabriel etc. But a step up is better than nothing. And this strut stuff is car-specific. KYBs may be awful on one car, and pretty decent on another.

By "bilsteins from an GXP" do you mean the front? By "stock springs" do you mean the stock front GXP springs? Some specificity is helpful. If this is what you mean, then yes, of course a V8 car strut/spring combo will raise the ride height in a V6 car.

Interesting point about rebuilding the Konis. The logistics of the process are not that appealing, however. Pull the struts, have a carcass of a car sitting at the suspension shop, wait how long for Koni plus shipping both directions?

Part number, specs, and/or link for Vogtland springs for the 2001 GTP? Is the GMPP spring and Koni strut combo still available? Part numbers or link? Similar info for SSC springs?
 
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if you're able t get comp g strut/springs on all fours go for it, they're stiffer than the standard gtp but your car will be sitting slightly higher by a half inch. ask me how I know lol. cornered great though.
 
Are these the Bilstein GXP struts?

ACDelco 505-548 GM Original Equipment Front Suspension Strut Assembly $309.84
ACDelco 505-549 GM Original Equipment Rear Suspension Strut Assembly $232.33

Pretty spendy. I would think the rears would be fine, but it is probably ill-advised to run the fronts as they will be designed for a heaver engine and stiffer spring. So one could only run Bilsteins on the rear. In which case it probably makes more sense to go FE3 on all four corners rather than mismatch. Cheaper too by $500. Significant, but paying labor this whole job is likely around $1,500.
 


spazzz said:
Here is the compg and GXP spring numbers
rear- TDK 10258881
front- FKJ 22133030
Click to expand...

Are these GM part numbers? Is the front spring "comp g"? Pretty sure I don't want a V8 spring in the front. I should mention some of this W-body option lingo isn't familiar to me. I read that comp g is a handling package, and I think it is for the V6 SC car. Feel free to spell this stuff out and assume I know nothing about the various W-body suspension configurations.

So the part numbers above are GXP in the rear, comp G V6 in the front, as appropriate for a 2001 V6 GTP? Too many choices, I do appreciate the help picking the correct parts. Probabaly 15 different struts I could buy if you include the usual suspects like Monroe, Gabriel and every chinese knockoff under the sun.
 
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FE3 and KYB AGX struts are about the same price. My tendency would be to get the AC Delco FE3 struts and new OEM springs as listed above by @spazzz. But I don't have experience to base this on. Anybody here try them both?
 
Those numbers are off my stock Comp G springs, I just dug them out.

Like I said,I have FE3 in front and the Bilstein in rear with SSC springs. Perfect set-up in my eyes and fairly affordable.
Get Delco professional mounts.
 
spazzz said:
Those numbers are off my stock Comp G springs, I just dug them out.

Like I said,I have FE3 in front and the Bilstein in rear with SSC springs. Perfect set-up in my eyes and fairly affordable.
Get Delco professional mounts.
Click to expand...

Thanks. After looking up those spring numbers they look like stock for many models of W-body, perhaps the springs aren't different for the comp G package. Maybe struts, sway bars, etc.

Did you not put Bilsteins in the front because they were tuned for a V8 spring? It only increases the price by $200 to put Bilsteins in the rear, and leave FE3 in the front. Are the rear FE3 struts known to be a bit weak? Just wondering about putting Bilstein only on the back end. And it would seem Bilsteins are the wrong valving for the front end.
 
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