So my 2002 WS6's suspension has been making an enormous racket lately. I'm at the point of considering just rebuilding the entire suspension system rather than try and track down each individual problem, fixing it, and then having it create more problems to track down. I'm considering getting the upgrade kits from either UMI or BMR to modernize the actual components as well as lose some weight on the front end since the car has an LQ4 short block in it (adds ~100 lbs, kits look like I could reclaim about half that extra weight). I've also been considering that if I do this, then I might also want to do the independent rear suspension conversion at the same time.

In terms of the goal for the vehicle, I'm working on making it a canyon carver. I'm using it primarily in the mountains and really want better handling for the twisties, and it does see some rare track time every once in a while. It has not seen a drag strip that I am aware of, nor do I have much interest in drag racing it.

I know it's all going to cost a lot of money no matter what I do, but without a good plan of attack it's going to end up being even more expensive. Short of the car getting squashed by a big rig, it's always going to be rebuilt (better, faster, stronger). It's a dream car of mine, so I may as well work towards that end.

Any advise, suggestions? How would you build a perfect suspension for a 4th gen Firebird? I'm also looking at what it would take to put MagneRide in it.

 

What size wheels and tires are on the car?
Do you care about ride quality?
How frequently is that relative to street driving?
How are the roads around you?

If this is primarily a street car, you may want to go in toe deep first, and just replace bushings with new rubber bushings, new ball joints and shocks. That last one, shocks, will have the most impact, Bilsteins for stock height to slightly lowered, Koni str.t, and Koni Yellows progressively better in terms of handling.

The umi and bmr kits that save weight are generally aimed at drag racing. The road racing stuff doesn't save weight, rather it uses joints that are more precise, but are much harsher on the street.

 

It is currently sporting the fourth generation snowflake wheels, they are 17x9. The tires are BF Goodrich gForce Comp 2 A/S 275/40R17 (ya I know summers are better, but this is used year round and I like the better handling in the rain). I do care about ride quality, the best I have to compare it to is a touring vehicle that uses magneride. That obviously isn't a drop in replacement at the moment though.

In terms of track time, we're talking maybe a handful of hours on the track per year, nothing spectacular. I'm in Dallas so the streets around town are mostly okay, but there are areas that have sections of uneven pavement with drops between slabs due to the earth beneath moving. They generally do a good job repairing that. The roads that the vehicle tends to travel on however are a different story.

It gets probably 80% of its use on state roads, the US highway system and the interstates. We prefer the mountainous regions have been on the Texas Mountain Trail and made several trips up to Deals Gap North Carolina and the Smoky Mountains. The roads up there can be less maintained and sketchy gravel at times. Tons and tons of sharp turns, switch backs, long sweepers, weird cambered roads that are crazy fun to drive up there. But it is literally pulling the car apart as I'm sending 3600 pounds around a sharp turn, and I hear every bit of it as it happens. =\ Look up some video of Tail of the Dragon to get an idea of the type of road it's been conquering.

This is not my daily driver which is a 2009 MKZ and this is more of a touring car that I use for rallying and cross country adventure. I've already been doing the toe deep approach for a while now. I'm at that point where I need to do all the bushings and that means pulling a bunch of stuff apart.

I started with putting Bilsteins around; the car is at stock height but does appear to be sagging on a couple corners. I did not do the springs yet, but I'm wanting something a bit stiffer on the front and rear to help with the roll its being subjected to. Getting the independent rear suspension conversion would be even better for corners and twisties, but that will have to be planned for due to its cost.

I know that UMI/BMR are more geared towards drag racing in terms of saving weight. The reason I am looking to save weight is because the LS1 needed to be pulled (made it just shy of 45K miles before lots of metal in the oil) and it has the LQ4 iron short block in it now. That added 100 pounds to the front end which is bit more noticeable going into turns. Swapping out the k-member and the a-arms would help balance it out a little bit; using the UMI Road Racer K-Member and the A-Arms should get back at least 30-40 pounds.

I'm also considering adding the sub-frame connectors. I think this would probably provide the biggest immediate benefit in terms of "keeping things together" going around these corners at a spirited pace.

Edit: Formatting.

Oh ya, it's already had the rear lower control arms replaced. They were completely thrashed.

 

I'm not sure I'd be too worried about offsetting the 100lbs, as much as the rigor of the parts, and making sure I hit the stated goal, - fix the rackety suspension, make it handle.

I would fix all the suspension bushings, joints, and end links. Run Koni Yellows, with strano springs, and an adjustable panhard bar.. Maybe upgrade to the hollow sway bars 35 front 22 rear. Have Sam help you dial in the shock rebound adjustments front and rear. With the roads being better in the south, then say the north east US, you should be happy with both the ride and handling

My two cents is to run street parts on a mostly street car. The umi or bmr boxed control arms will use rod ends or roto joints. Either of those will make the ride harsher, noisier, and rod ends hate road grime. Pretty much even one rod end will clunk and bang, and lots of them will be rattle trap city. You'll hate it. The rod ends will wear out quick and need to be replaced when they do.

The rotojoints are better, but in my experience I prefer johnny joints from currie, if that is the route you must go. The liners in johnny joints are urethane, they absorb road impacts better, they articulate like a rod end, and they will put up with any kind of road gunk.

I also wouldn't bother with subframe connectors, they don't provide torsional resistance in a beneficial way, and they add weight. They also channel noise and road harshness in to the cabin.

Magentic ride control is programmed in to the ECU and would have to be tuned specifically for a 4th gen. If there is a company that does it I don't know of it. IRS is unique, but a pain to install, and even more of a pain to tune to produce a competitive result. Heidts is pre-canned SLA design, but any of the IRS's will have you chasing spring rates and damper valving to get the rear to work with the front. The strano set up is a well proven recipe.

 

I'd suggest contacting a vendor named StranoParts; Sam has many years experience racing and winning nationally with these vehicles, but also knows the challenges of daily driving one. He was never one to sell me something that he didn't feel I needed, but would take my money if I was hard nosed about it. I have a mixture of parts from Sam and non-vendor, and I would recommend going with all one vendor to ease setup and maintenance questions.

Subframes: My daily driver has 201K miles on the body and never had sub frames (even when I autocrossed for about 7 years), and I don't have any unusual squeaking.

Wheels & Tires: Go with a diameter that fits the brake caliper & rotor package you need for your track days. If you aren't making a lot of power 13" rotor is probably adequate, and a 17" wheel would be fine. That said, you might get away with 17" wheels but good tire compounds are getting harder to find in that size. 18" will be a little less forgiving on street driving but opens up more tire compounds. Everything the car does has to be controlled through the tires, so get the best tire compound you can afford for your intended use. If the budget is there and you need different wheels, opt for a strong, lightweight wheel (18's in the 20-22lb range, or 17's a few lbs lighter) for less MOI. Something like a Forgeline GA1R or Finnspeed F10.

Shocks & springs: I'd opt for at least the the UMI complete coilover kit, but it's only single adjustable (you may only need single). You can certainly opt for more adjustable solutions which are more expensive, but then you're getting into race shocks and you have to expect them to need rebuilds every couple of years. I went with Penske in 2017(?) because the magneto shock controllers were not available for integration with the f-body, and the spool-valve dampers required a lot of information to build them for a vehicle. Even if they were available, I bet they would have been significantly more expensive than the Penske doubles I have (which cost more for the fronts than the entire UMI kit). The correct shock valving will mitigate many of the undesired behaviors of lesser dampers.

Bushings: Rod ends can be noisy if you pick cheap parts, or install cheap rod ends supplied from a vendor. My rear suspension is all rod end (including endlinks and shocks) using 3-piece joints with PTFE liners and I get a little noise from the LCA's after about every 10-15K miles. My front suspension is still using OEM control arms, but using rod end shocks and endlinks. Don't go cheap if you opt to try rod ends, and also use Seals-It rod end covers to help keep contaminants out of the bearing to extend their life. I personally never use the rod ends supplied by a vendor, I buy the kind I like.

 

These guys above give solid advice, follow it.

But before you go spending any money yet do yourself a favor and get under the car and tighten some bolts to see if that helps with the racket. Tighten the PHB bolts, the rear LCA bolts and inpsect the swaybar D bushings and endlinks and see how they look. Im also betting that the aftermarket rear LCAs you have are a source of some of the racket you are getting.

 

If you have the money, look into the KW coilovers. Great handling and comfort IMO. I got the V3 since I like the double adjustability of bump and compression, that and I'm always switching ride height and ride quality whenever I feel like it. I added the UMI adjustable LCA and PHB and made it even better in regards to being planted while taking a corner at a fast speed.

 

A Watts link is a definite upgrade from the panhard bar, and way cheaper than doing the IRS. You can put the Watts on yourself in a day.

 

This is where I was a few years ago. Right now my T/A is exactly where I want it, In the mountains she's a pleasure to drive. Dual 3" exhaust out the back echoing off the mountains sounds glorious. Completely new suspension means she rides firm but controlled. No rattles, clunks or noises to report. This was probably the hardest part to track all of the typical F-Body noises down. Oh, and at the local autocross, she's around a second off decently driven trailer'd C7 Z06's.

See my mod list below:
https://wheelwell.com/chris-rosioru/...ntiac-firebird

Essentially the order I went in:
1. Suspension biggies : Shocks, springs, sway bars
2. Brakes
3. Tires
4. Suspension misc: Watts link, LCA, bushings, torque arm...etc
5. Drivetrain: clutch, gears, shifter
6. Engine: Cam

 

I do not currently have any after market parts on its suspension with the exception of the rear lower control arms which got replaced a couple months ago. For the time being, she is going to exist as she currently is. I went to run errands last Tuesday and had the joy of finding a puddle of differential juice under her, so she's at the local GM mechanic for a new rear pinion seal and gasket. =\

After much consideration, my current plan when I can get the Firebird more attention is to get new springs first of all. Since it is the work horse when we are rallying (Miatas don't have much space), it ends up getting loaded down. Throw in the additional weight on the front end with the iron block, a human, dog, and all the gear and luggage... I'm probably going to shoot for 500# in the front and 250# in the rear. I'm not planning on using lowering springs so it'll end up at stock height which should actually be higher than where it currently sits which I'd actually prefer for visibility. At the same point that the springs are getting done, I want to take a good look at each of the wheels and all the parts involved in the suspension for it and anything that's suspect will get touched. That'll probably also be the best time to address bushings.

I did find a place I can rent a lift at, so I got that going for me at least. =D

 

If you are doing springs then you should be doing shocks as well unless you like a bouncy, floaty and jarring ride. The factory shocks can't control the soft stock springs none the less much stiffer ones. Also 250lbs/in in the rear is really stiff, these are solid axle cars and you don't normally run higher springs rates like you would on IRS cars. If you want to try a stiffer rates for when you have stuff in the back then buy some dragbags or airbags that mount in the spring and you can inflate when you want to increase rate and deflate to decrease rate, I would just try them with your stock rear springs for now. If you really want different springs then I would just try something like 600lbs front, 150lbs rear with the air bag as well. Get some good shocks on there, Koni sports are really good if you don't want to buy adjustable coilovers.

 

It already has new Bilsteins (well relatively new, just put on a year ago, less than 10k miles on them) around. As for spring rates, the 02 WS6 has 360# up front and 180# in the rear for stock from what I've been able to find. 600# seems like it'd be a little bit too stiff for my taste. The real problem is not being able to try before you buy! =D

 

For years I had Koni Yellows on stock springs, and the ride was good when shocks set to full soft. At full firm it was way too harsh on the street (IMO) but great for autocross. On Strano springs, on full soft, it's still OK on street but certainly firmer than stock springs. I know you "just" put new Bilsteins on, but shocks are really the #1 performance (handling) boost on these cars. The difference when I put Koni's on was shockingly noticeable in a better way, all the time. I would tell someone if you could only ever do 1 mod to your car, put Koni's on.

One other weird yet maybe related thing since I recently dealt with it - make sure your axle vent tube (little plastic unit) is still there on top of the axle, and not blocked/caked with dirt/grease. Which could lead to overpressure and leaks, or if not there (how my axle was missing it IDK) can leak out too.

 

Those are 1LE spring rates, the 02 WS6 should have the same spring rates as the base V8 car, with a 32mm front swaybar in place of the 30mm over the base car.
Your spring rates should be : 292lbs/in front, 114lbs/in rear.

http://www.angelfire.com/my/fastcar/suspension.html

Bilstiens will likely not be able to handle the higher rates like what you want to run very well, much better than the stock shocks but still leaving some to be desired.

 

You can get double adjustable Penskes for much less than what you paid. Personally I see no reason to bother with the UMI stuff at all for how cheap the Penskes are. YMMV

 

Strano springs wont lower the car much and the increased spring rates should handle the weight youre talking about better. Strano springs and Koni adjustable sports are the decade long go to for these cars and there is a ggod reason for it. I promise you will think you are in a different car. I would go that route before I considered any other suspension parts - aside from rebuild type stuff. I have Koni's and BMR springs (similar to Strano) and don't have any interest in more upgrades really. It's such a good car now, for my purposes there really isn't a need for more. Not that I dont fantasise, lol. But if I spend more money it will go to other things.

You can always sell the shocks and springs here if you arent happy or go with something else. You'll get good money for them even used.

 

Link that **** Bro-Hammer.

 

I got them through UE, which appears to be the same place you obtained yours based upon their website blurb about you...? I'm okay paying a little more to buy from a person who has a good track record (pun intended) with the solution.

 

Yes that is who I got them through and they are great. You probably did 8300s all around. I went with the 7500 doubles in the front to keep costs down. Same valving and everything just with a smaller adjustment range. I have never once needed that extra adjustment. I’ve become a damper snob at this point. Either slap some Konis and Strano springs on it to freshen it up cheap or if you want to spend money on something above and beyond that just do it right the first time.

IRRC it was either 2600 or 2700 for the whole set, but I did supply my own springs.

 

I got mine from Unbalanced Engineering who you can find through google very easily. They are built specifically for each customer so you would have to contact Jason there to get an actual quote.