LET ME APOLOGIZE NOW FOR THE LONG READ......

I did a search, and i cant find what im asking. Most of the suspension questions are about; Are Bilsteins/Eibach REALLY that good? REALLY? REALLY REALLY?

Anyways, i have a 1987 firebird formula, and im almost dead certain its original suspension. Im not exactly sure what the stabilizers and spring rates are, but they are on the softer side. I can post RPO or measure if needed.

My bro has a 1983 Z28, cloned to an 86/87 Iroc, and i think he has suspension (factory replacement) from an iroc, or z28. Very beefy, but not aftermarket.

I like how soft my suspension is, its very nice to drive on and you could cruise forever on it in comfort. Has that "land boat" cadillac feel to it.

However, i dont like the suspension in my bros car, its just a little too stiff for me. I dont think its pleasant over a long cruise.

Thats what i like; heres what i want.

Its a v8 car (mine), with a 355, and hopefully in a few weeks, t56/ and posi rear end. However, since the suspension is so old, its ok during cruising, but as soon as you show it a turn, it gives up.

I was having some fun on a back road with my freind and his 07 mustang, at about 110 km/h in the twisty canadian shield roads, and he had nothing on me on the straights, but as soon as i approached a turn, i DID NOT feel safe at all.... I had to slow right down to about 50-60 km/h. HARD on the brakes. They were behind me, and mentioned after the ride, that the back was not sticking to the road very happily, and i could feel the insane body roll, and just overall unsafe feeling...

So assuming my brother has the highest available stabilizer bars 36/24? on his iroc, and the highest rated springs from factory. Which is a little too stiff for me, even though the handling is amazing...

What would be a good choice for me? Stabilizers front and rear? Springs, and shocks?

Im looking for ride quality, and handling, in that order. When i say handling, what i described is the most abuse it will ever see. Its a street car/driver first, and a weekend racer on occasion.

Also worth mentioning, just from visual, my stab. bars are much smaller than the z28's, you can tell just by looking. I have upgraded from 14" to 17" wheels, with 275s all around. And i plan to be using Moog suspension, with a decent factory replacement shock/strut combo. The moogs will be cut, im looking for a 1.5" drop. I will also be upgrading to umi SFCs, edelbrock STB, and wonder bar and panhard bar, havent decided whether aftermarket or modified yet.

I appreciate anyone who will come on here to tell me to use bilsteins and konis, because everyother shock/strut is useless, but honestly, its not a race car, i should be ok. I cant afford that stuff anyways. Thanks for any help.

 

Well if you want better handling your going too suffer in ride comfort its usually how it is no real way around it. I would replace all your bushing replace your springs < theres probably worn and saggin and not performing up too par. If your not looking for hardcore peformance and u still want a good ride get some sensatrac struts from advance are somthing and kyb shocks. Make sure your panhard bar is straight those factory ones like too bend and it doesnt help handling at all if it is. The tire width will help cornering also upgrading your sway bars shouldnt hurt ride comfort much at all so upgrade those its the spring rate and sturts/shocks that do most of that

 

Absolutely, i know the ride will suffer for handling, but theres a tolerable comprimise.

So if you know what i like and hate for handling, and what i hate and like for ride, maybe someone can recommend a factory suspension "package" if you will. These cars DID come with a few different choices for sway bars and springs right?

Im looking for numbers, specific sway bar sizes, and spring rates (or part numbers) that will give me decent handling without being too stiff.

Obviously it will be stiffer than what i have, cuz no doubt my suspension is worn, but im sure someone can suggest a balance.

 

Moog Iroc springs are about the best stock springs you can get its going too feel alout more like your brothers car thou with those in there. You can get the sophn set sway bars some ppl say the 1" in the rear is overkill but i like it. Are you could go with gm bars i think there like 36mm front 24mm rear i might be wrong about. As for spring rates id stick around 700+ any softer and youll be scraping your bottom alot going over bumps and stuff the back 150 are so. upgrading all your bushing would be good poly will be the cheapest route and dont go with outrageous shocks and struts but in my opinion as soon as you do this stuff youll start craving peformance more and more and ull forget about ride comfort lol. You could also get adj lcas and relocation bracket helps wheel hop and sub frame connectors are a must even if you do buy the bolt it ones make sure too go get them welded afterwards youll be pretty good after all that lol. just a price wise aspect i paid around 3500 for my complete suspension once i was all aftermarket stuff thou

 

You may already have the 36/24 combo on your firebird (86-92 on some models and 88-92 on some Camaros. Your brother's car probably has the 34/24 combo).

JamesC

 

He already stated hes brothers are visibly larger so i doubt hes running the 36mm/24mm combo

 

You very well could be correct--and probably are. However, eyeing as a measuring device might be problematic.

JamesC

 

Yes i agree a tape measure is always better than the eye. I was just consedering that if hes brothers suspension is factory and he belives theres no doubt hes is bigger he probably doesnt have it. but theres always a chance he might have a drag race sway bar lol =]

 

Ill give u some definate numbers when i get home.

Definately not 36 front, possibly 24 in the rear though on my car.


P.S.

I appreciate the opinions and all, but lets try and keep it on track here. I described what kind of suspension parts im lookin for, plz reply if you can put dimensions or part numbers to it.

 

Good luck.

JamesC

 

Springs and shocks are what give you that "holy cow, my tailbone!!!" feeling.

Better sway bars can help your car handle significantly better, without that terrible stiff feeling. It's kinda like having your cake and eating it too.

Use a crescent wrench on your swar bar, then measure the open part of the wrench, that's more accurate than a ruler or something (assuming you don't have a caliper).

Bigger sway bars with poly bushings will help a lot. You have SFC's right? Those won't comprimise anything, but will make the car feel more solid. Not "crunch...oww!" solid, but lack of twist type of solid.

Your springs are undoubtedly worn out. Moog makes many flavors.

MOOG 5660, 5662, and 5664. That's RS, Z-28 and convertible, in that order, increasing stiffness. I have the 5664's, and that's *not* what *you* want. I love it, but you wouldn't.
New 5660's would probably be a good idea.

Do the typical shock test on your car, push down on a corner and count the rebounds. I think your shocks have probably leaked out all their good stuff and are now decorative. New entry level factory replacement lifetime warantee garbriels/monroes will bring you back to the norm.
Crappy tire puts those on special every few months with the 2nd one half off deal, and keep your receipt - when they wear out, get new ones for free.
Those shocks are CHEAP too, so if you decide you want stiffer, you can always get the BILSTEINS later. Yea, apparently they are that great At least they're adjustable so you can go from soft all the way up to rock hard.

 

I dont have calipers, i was just gonna measure the circumference in the middle and do C = 2(pi)R multiplied by 2 for the diameter.

I dont have SFCs yet, UMIs on the list, i wont have the budget for this stuff till about spring or summer, but i can collect junk yard sway bars in the mean time.

So i can go with the stiffest sway bar combo, and a softer spring/shock combo, and ill still have decent ride quality?

My struts and shocks are actually decent, push down as hard as you can, it rebounds up once, and settles back to normal, on all 4 corners.

Is there a way to find out what springs are on a car? Serial or part number somewhere maybe?

I have a feeling my bro's Z28 has the 5664 or similar spring rate. Like the streets are pretty good where i live, and the highway is decently smooth, but u can feel a blade of grass if u drove over it. His car is fun to drive, for sure, but i couldnt live with that everyday.

James, or some of the more experienced guys might know this, but was i wrong in saying that poly bushings are noisey. I read somewhere they squeak quite a bit.

 

Yea, that's what I was afraid you'd do re: measuring circumference. The error on that adds up fast. Just grab your monkey wrench and a kids ruler.

I have never heard my poly bushings squeak before. Just grease them with the supplied lube. They also make polygraphite ones which are apparently self lubricating.

 

polys will squeak if you neglect them and dont grease them some ppl grease there bushing when they first put them on then leave them for yrs and then they complain when they squeak lol. grease em at least 2 times a yr. online170 yes i would go with the best sway bars you can get sfc and then go softer on shocks and struts and ull get better cornering without horrible ride i still think ull go all performance once u get into it lol =] get softer seats and a *** warmer now thats ride comfort lol =]

 

Think about it logically: what touches the ground and what controls the suspension: Tires and shocks. That's where the money should be spent.

If you want to handle well but ride softer, weld on SFCs, get some softer GM springs, the big sway bars with poly bushings (don't really make the ride much stiffer), and some good tires. Just remember, if you cut the Moogs, they will get stiffer. Another option on the springs is to get a set of SSS, Eibach Race Springs, etc in the rates/height you want.

Don't spend much on other things such as control arms, panhard bars, and those goodies until you get some GOOD tires and GOOD shocks. If you want handling with softish springs, don't go with KYBs, Monroes, etc. Bilsteins or KONIs will be your best bet. Good (adjustable with KONIs) ride, good handling. I think you'd be pleased.

On the bushings, my front bushings (black) and have a grease point; these don't squeak much . The rears (red, don't know if color makes a difference) non greaseable squeak then the suspension travels alot. Places you don't want poly is in the LCAs. I had it and didn't like it. Now I have heavy duty rubber on the body and rod end on the axle.

When my suspension at full stiff with the Eibachs, it doesn't compress enough to rebound... Is that good? ahahahaha

 

Alright guys, thanks for the response. Now my bro's car isnt parked at my house, its at a freinds for the winter, i happened to swing by today so i measured. I dont think it matters now, because weve concluded i should put in the biggest sway bars i can find.

In any case, the Z28 is 34mm front, 24mm rear. James C, you were spot on. I didnt have a large enough adjustable wrench to measure the front, so the result might be a little skewed, BUT it is ATLEAST, and most likely 34.

The firebird is, 30 mm front, and either 16mm or 17mm rear. I took each measurement 3 times, and thats what i read.

I have upgraded to 17" wheels and decent falken tires. I am aware that moogs will get stiffer when cut, however, i dont think they will get anywhere close the 5664 spring rate. I think i will pick up a set of 5660's and similar front and back, and lower 1.5", and bolt on a wonder bar. Panhard bar, i wasnt going to get an aftermarket one, just box in the one i have now if its straight. And SFC's are on the list. For shocks, i wil have to wait an see how deep my pockets run at the time. I know its a crucial part, but i need to redo the rest of this suspension as well.

One more question. I have read several times, that body flex and bushings give, will ruin the performance of shock/spring combo. Would you recommend solid strut tower mounts?

Thanks for the input everyone, i will post the results when i get this stuff done.

 

I have the HotPart strut mounts, and they are alot better than the stock replacement stuff. I say get em.

 

OK so after i installed the T56, my car actually feels like its pushing over 400hp. Not having my speedo wired up yet, its hard to tell how fast im goin, and 6th comes up way too quick. WHen that happens, i notice how unstable the car feels. So i will be digging deep in my pockets, past the buttons and pennies, and getting me this suspension soon.

I just wanted to know. How good are the moog 5660's? I hope they arent too soft. I was having a hard time picking between the 5660 and 5662s. Id like to NOT be able to feel every grass blade on the road, but still be stable in a quick turn. So 5660's or 5662?

I know i mentioned earlier in the post that im looking for a "softish" ride, but i need the car to be stable at high speeds as well. The springs will be cut for a 1" drop, and im trying to find the resulting spring rate from a post from BmonteSS from a while back.

I also wanted to know. If its a good idea to get the Iroc style shock/struts instead of the matching strut.shock combo.

Meaning if iroc's took moog 5664 spings, id imagine they have a matching iroc shock/strut combo.

Same for moog, 5660, and 5662.

If i went with the moog 5660's, would it be ok if i added iroc shocks/struts instead of the matching 5660s?

I dont think the ride would be much harsher, but id probably have alot less body roll. right?

 

You are worrying about the wrong thing. Don't bother with the springs yet. What type of shocks do you have? Shocks and struts are what control the chassis roll rates. 5.7 above already mentioned to you to buy GOOD shocks. I would take his advice. Just slappiung stiffer springs in there is not gong to give you driver conrol stability- shocks will.

As for high speed runs, areodnamics comes into play and the front is probably digging and the rear lifting causing the normal unsecure feel of underdampered vehicles. Slight corretions in the wheel make it feel loose, but when you press it it will still plow- its common charateristic in stock suspension vehicles

GOOD shocks, thats it for now.

 

I should have clarified, its not the aerodynamics making it unstable (although i am aware that the front likes to lift), its the occasional change in incline on the highway, or the occasional bump, that makes it feel like the car is out of control.

As for the shocks, thats what i wanted to know. However, i cant afford $700 bilsteins right now. Were the shocks different for different optioned vehicles? I will just go with the "stiffest" i can find then, probably the iroc/convertible option.

 

Putting stiff springs on a car with shot shocks, you'll still have a bouncy (but stiffer, possibly less comfortable) ride. It will 'feel' better because the stiffer springs will risist the energy of the car's inertia more, but it won't control it the way shocks will. People put LCAs, and PHBs, and springs, and all the little components of the suspension on the car and forget that shocks control the springs, not the other way around.

 

If his springs are bad and he only replaces the shocks/struts there is a good chance he could decrease the life of his new shocks especially if they bottom out

 

Im talking about getting stiffer SHOCKS not springs. What would happen if i got EVERYTHING new, but matched a higher option (stiffer shock) with a lower option (softer spring).

 

...OK..... Here's your next question- He's not bottoming out right now with the old shocks, So why on earth would he with GOOD quality valved shocks?
Stick to the situation.

 

Nice to see you back Dean.

Just to third the idea. Spend you money on shocks/struts. If any one thing is going to make the biggest diffrence on performance, it is them.

--John

 

If you got a softer spring set (just don't get V6 springs, lol) and a good set of shocks (such as the nice Bilsteins, or either KONI set and maybe high end Tokicos) you would have a car that would have a fairly nice ride and still be able to play in the corners fairly well. It would be a compromise though. You wouldn't have the same characteristics as a car with stiffer springs, but that's what you seem to be after. You can compesate for the springs with large sway bars. I would get 36mm front bar and a 24 rear and see how that works. I would invest in some nice tires as well. The tire will also determine a lot in the way the car handles and rides. I'm not completly sure I'm right with this, but I don't think I'm far off.