LS4 Performance - Impala SS Bilstein BMR ZZ GXP Suspension Upgrades Done!

Here is an outline of my suspension and brake upgrades on my 2008 Impala SS. The car is rock solid after the upgrades and handles terrific! Very responsive! I did these upgrades in late 2009 and the parts have about 40,000+ miles on them at the time of this post. To the best of my knowledge everything is holding up great. The ride is FIRM! Probably a bit too firm for the liking of some. I don’t commute in this car, so it’s no big deal. At least now the rest of the car is up to snuff with the powerful engine. Scroll down for pictures of all the goods. Enjoy!

Parts Installed:

ZZ Performance Front control arms $500.00
Bilstein Struts P/N: F4-VE3-F315-H0 Front P/N: F4-VE3-F316-H0 Rear $900.00
(Bilsteins are worth every penny!) (Tire Rack)
Eibach springs P/N: 38108.140 (eBay) $250.00
BMR Rear suspension arms $550.00
Addco rear sway bar P/N 639 (eBay) $150.00
Moog K6662 Rear sway bar end links (Amazon) $ 50.00
Energy Suspension front sway bar bushings 9.5167R (Amazon) $ 20.00
Gran Prix GXP Brakes (Used, Morad) $550.00
4 Raybestos GXP brake rotors $200.00
Ceramic Pads (front and Rear) $100.00
Don Rome Strut tower braces $175.00
Billet wheel spacers $275.00

Total: (yikes!) $3,720.00


Improvements noticed:

Lift and squat under hard acceleration greatly reduced.
Steering response greatly improved
Traction improved.
Torque steer effects reduced.
Dive under hard braking reduced.
“See sawing” (car rocking side to side under hard acceleration while passing) greatly reduced.
Tire wear notably improved.
Just all around more responsive and fun to drive.

Downsides:

Very firm ride. (Not bone jarring, but all luxury feel is pretty much gone)
Polyurethane bushings need to be greased frequently or they get squeaky.

Front Suspension Images:

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Rear Suspension Images:

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That's a lot of good info there

Wow... that's awesome!

thats great when you first posted pictures of your suspension I was wondering how you liked everything. How do you like the rotors and warping or anything?

Lol at "warping."

My cringe moment was when I read about the 1500 grit sand paper being used on the caliper logo. That's a sore spot for most of us...

My cringe moment was when I read about the 1500 grit sand paper being used on the caliper logo. That's a sore spot for most of us...

Why is that?

very good thread. that suspension work looks awesome

Hawkins04 - When I'm in the mood to drive hard the car shines with all the undercar mods. A blast! However when I just want to cruise, it would be nice to flip a switch and have it ride like a Buick. Guess I'm getting old. :( LoL. Regarding the brakes, after nearly 2 years of use the rotors are starting to show some wear and if I lay into the brakes hard from high speed I will notice some pulse in the brake pedal till the rotors cool off. Seems like the pads outlast the rotors in this application. At least that's my experience.

GXP25 - I never thought about it, but I can see how some in the GXP camp might see defiling GXP calipers like I did could be viewed as sacrilege. LoL. :devil:

Very nice. Got any side shots to show the drop? I bet that thing's a blast to drive! I'd love to do all that to my GXP. I've always wondered if I could get it to handle like my VW lol.

Regarding the brakes, after nearly 2 years of use the rotors are starting to show some wear and if I lay into the brakes hard from high speed I will notice some pulse in the brake pedal till the rotors cool off. Seems like the pads outlast the rotors in this application. At least that's my experience.


was doing some reading on 'brake warping' and in this article i found the writer claimed that in almost all cases of brake warping its the resin from the pads deposited onto the disk that causes that pulsing. improper break in of a new brake system allows this resin to deposit unevenly causing it to be out of balance and 'uneven'.

the article said you have to get your disks resurfaced or use metallic pads to get rid of that resin.. not sure how true it is, but heres the write up if anyone's interested.

http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

Here are a few exterior shots. Car has about a 1 inch drop and the wheels are spaced out about 1 inch. This gives the car a pretty good stance. lunchbox_89 - I agree the pads may not have been bedded in correctly. Also, they've always squealed like crazy under normal braking as well. Makes riding with the windows down unpleasant. Tried the anti squeal goo on the back of the pads. Didn't work. Just got brembo rotors from brakemotive. Having them cryo treated and will put them on this fall. Will definitely do a proper bed in this time around.

Here are a few exterior shots. Car has about a 1 inch drop and the wheels are spaced out about 1 inch. This gives the car a pretty good stance. lunchbox_89 - I agree the pads may not have been bedded in correctly. Also, they've always squealed like crazy under normal braking as well. Makes riding with the windows down unpleasant. Tried the anti squeal goo on the back of the pads. Didn't work. Just got brembo rotors from brakemotive. Having them cryo treated and will put them on this fall. Will definitely do a proper bed in this time around.

HA welcom to the club i have a few friends who have gxps and the breaks always had a bit of a squeal dunno why :bang:

I'm insanely jealous as I was looking to do EVERY upgrade you have (except for brakes, of course..).. Obviously, $$ is my main hurdle, lol.. Your ups are extremely cool in my books.. Screw a soft, comfy ride! And I bet you quarter ET's will see an improvement as well.. I'm assuming all these mods help put out another 30% of the power you lose to the ground and should hook better, too.. All you need now is some fancy rims with some GAPS between the spokes so you can show off all the purdddyyy

Nice work bro,

The GXP's have the goods.

Where did you get those spacers from? Are the Impala's wheels 18x8's or 18x7's? I want to put those spacers on the back of my GXP cuz the wheels are 18x7 and i want to fit a 255/45/18.

Thanks

Greg

Sticky this Travis. Lots of detail and Part numbers.

Here are a few exterior shots. Car has about a 1 inch drop and the wheels are spaced out about 1 inch. This gives the car a pretty good stance.

WOW that looks bad ass,wish I had 3k to drop on the suspension and brakes

98GTcoupe - The spacers are from: http://www.wheeladapter.com/ I'm afraid to admit I do not know the width of Impala SS wheels. Anyone know?

98GTcoupe - The spacers are from: http://www.wheeladapter.com/ I'm afraid to admit I do not know the width of Impala SS wheels. Anyone know?

7" on all 4

Stuck!

Please keep us updated on the front LCAs. Most tubular LCAs don't do well under daily street driving. Also, the trailing arms answered a question for me. I don't think they would fit at all with my 245s on an 8" wheel. But the relocation seems plausible.

Great writeup! How is understeer now?

AlabamaGuy - Thanks for the sticky. I spent 2 days putting that post together. The front LCA's have 40,000+ miles on them now and seem to be doing well. I had new tires and an alignment done a few months ago and everything checked out ok. The front heim joints are not resistant to corrosion and the red coating by where the heim joints screw in was chipping so I painted those areas black to seal them from the elements. Understeer is reduced. I notice that when pushed to the limit the rear of the car wants to come out, but letting off the gas snaps it back in place. For it being a big heavy car with most of the weight hanging over the front wheels it does well considering.

AlabamaGuy - Thanks for the sticky. I spent 2 days putting that post together. The front LCA's have 40,000+ miles on them now and seem to be doing well. I had new tires and an alignment done a few months ago and everything checked out ok. The front heim joints are not resistant to corrosion and the red coating by where the heim joints screw in was chipping so I painted those areas black to seal them from the elements. Understeer is reduced. I notice that when pushed to the limit the rear of the car wants to come out, but letting off the gas snaps it back in place. For it being a big heavy car with most of the weight hanging over the front wheels it does well considering.

That is interesting. Throttle tends to induce understeer where trail braking or mid corner lift will rotate the back end.

Well to be bluntly honest considering all the parts I put on and how much I enjoy spirited driving I probably don't know what I'm talking about in regard to understeer and oversteer etc. Let me tell you what prompted me to do all that work:

1) I hit the stock brakes from speed and the car felt like it wanted to shake apart and the speed didn't come down quick as I would like. So I thought: "Stock brakes are worn out and they suck". Didn't want to put new "suck" brakes on, so I found the GXP brakes idea and went with it. Problem solved!

2) Went to pass a slow poke (with stock suspension) from 30-50 MPH and as I came around I almost sideswiped them because the car see sawed side to side and tried to torque steer right into them. Scary! So I thought: "stock suspension sucks and cannot manage the power this car puts down". For every car problem there are plenty of spendy solutions! LoL So I did all the other work and now I can pass slow pokes without worry of trading paint with them. :D

I think you are correct if memory serves. The couple times the back end of the car swung out on me was after lifting the throttle and then too much steering input. But thankfully is snapped right back in line. More so than I think it would have in stock form.

I really don't know the cars handling limits. I'm afraid to push it because it's my only car and I don't want to find out it's limits the hard way. :bomb:

Oh, and here is a random bit of info. Before all the upgrades I was previously running the Eibach springs with the stock struts and it's not a good combo. The stock struts simply are not able to dampen the stiffer springs properly. Car bounced around and did all kinds of weird stuff with that combo.

That's a good thing that it came out like that! Good to hear from someone who has already done what I plan on doing. Right now, on mostly stock suspension, I have to make the car oversteer when it begins to understeer. Usually a pulsing foot on the brakes and sometimes Sharp have to the throttle will u.settle the back end and push me on around the corner. If I could make it do that on its own, predictably....I would be a happy camper.

I have a Impala SS also, I want to do the GXP brake swap. I saw from the pix that you had a pedal is this needed to improve pedal feel? It would be awesome if you could post or pm a list of parts to take off of the GXP to make it work properly. Thanks.

All I'm using from the GXP brake system are the: calipers, brackets, rotors, pads, and hoses. I'm uncertain if the GXP master cylinder or any other components are unique to the GXP system. Anyone out there know? I never swapped the brake pedal out either. I'm curious to know if the pedals are different between the 2 cars. Anyone know if the pedals have different part numbers? The GXP brakes work much better then the stock Impala brakes. Pedal feel is not the greatest. Not sure why. Could be due to not swapping the brake pedals out. I did thoroughly bleed the system. Pedal just isn't as firm or high as I'd like. But as stated above the brakes work great.

Thanks that helps alot.

O8RedSS: Was I surprised as heck to see my car used as an example in your suspension build, I am honored. If you don't know it yet with all the upgrades you and I did - our cars will stay flat when taking corners at higher speeds. Something you will definitely like.

Very helpful write up! Glad I waited to start on mine. I have a few long shot questions to ask.
1) Do you run negative camber in the front - if so how much?
2) How do you stay in place with the flat bucket seat?
3) Have you any concern about oil starvation on an extended lateral G turn?

BTW if you want to test the limits why not try some autocross. I prefer road courses but I think less risk on autocross.

Nice thread right here, work looks great. I'm thinking of going with the Bilstein's paired with lowering springs on my Monte when the time comes to replace the factory struts. Don't know who I want to go with for springs yet. I've had Eibach's lowering springs in the past but I've heard good things about SSC's also.

Will the Eibach work on the Monte I want to order them this week???

Will the Eibach work on the Monte I want to order them this week???

Eibach does not make springs for our cars anymore, not even the 2000-05 Monte. SSC, CM (Canuck Motorsports), and Vogtland are the three I can think of off hand that manufacture springs for the 2006-07 Monte.

Are all these parts needed to lower a impala ss? Lol Im looking to drop mine a inch all around