I have done a search and not found too much on the topic. What is needed to lower my Z one inch in front and back?

 

The Eibach pro kit will get you a 1 - 1.5" drop. You could also cut the stock coils - use a saw, not a torch.

I may have a set for sale soon - I'd don't care for mine....

 

I had thought of cutting a coil, but how would you lower the front to match? Also, where can you find the Eibach pro kit?

 

Cut the fronts the same way as the rears - they're just harder to get out.

There are plenty of Eibach springs on E-bay.

 

I dont think i have springs in the front, just struts? i have a 91 z28.

 

you have springs in the front. people on here wouldnt say to cut something that isnt there.

 

TY! Also, i heard it was not good to cut your spring one coil. Is it better to get a spring kit such as the Eibach pro kit? If so, why?

TY again!

 

The springs are there - look behind the strut and you'll see them. Our cars aren't like newer cars, that have the coil over the strut....

There are two main problems with cutting - people do it wrong (torch) and ruin the springs, or they cut off too much. One coil may or may not be too much, depending on the spring. I'm sure there are plenty here that can give you pointers on doing it yourself.

The benefit to the Eibach (or other similar springs) is that they are ready to "drop in". They are the right height - out of the box. Most of the aftermarket springs are a heavier spring, which means better handling (but also a stiffer ride). The only real downside is that you have to buy them, where cutting them is "free".

I bought my springs, because mine were old and I didn't want to mess with cutting them - the choice is yours to make.

Good Luck

 

So what is the best tool to use to cut the springs with? I know not a torch! What type of saw?

 

Uhhh a hacksaw?

 

That's what I thought, but was not sure..ty

 

Best way I've found to trim springs is to use a metal cutting blade in a 7 1/4" circular (Skill) saw. You'll only need about 30 seconds to cut right through each spring! Start by removing 1/2 coil from each spring. Let it settle for several hundred miles to see if your new ride height suits you. You can always trim some more if the drop is not enough. Years ago I used the "hacksaw method" only to quickly learn there is a better way. Let us know if you need more help or information.

 

Ok I have a question.. Do you cut from the top or the bottom of the spring? It's top, right?

 

Good question. On the front springs, cut from the bottom. Prior to removing the springs, note how the ends are oriented in the lower control arms. After trimming the springs, install them with the new (shortened) end covering one, but not both, "inspection" holes as were the original springs. The TOP of the front springs is flattened to to seat properly. Do not trim the top of the front springs. On the rear springs, the bottom of the spring is a "pigtail" so only the top can be cut. Retain the insulators on top of the springs with zipties or tape.

 

So, how much should be cut to lower an inch? I was guessing one full coil?

 

sawzall will work the best i'de imagine...........I read where in a camaro tips and tricks book it was recommended to cut only 1/2 of a coil when lowering.

 

So, how much will 1/2 a coil drop the car?

 

I am not sure......I will try and locate my book to see if they gave that info .

 

Well i think I will do this to my car too. The darn thing already doesnt sit level, so I may have to get used ones. And I'll have to go read up on how to remove them..

 

Front

Cut the front so that it is 1/2 inch shorter than it was.

Cut the bottom as the top is usually flat and seats in the coil bucket. The bottom needs to be feed into the lower contol arm in the orginal fashion.

The ratio of the spring height to the ride height is about 2 to 1.

I do not know how much of a coil this is. I would use a side cutter on an air tool for the best cut.

Keep measuring the spring by placing it on the floof and measuring the inside to a strait edge across the top.

Realign car as now it will be toe out due to the lower control arms becoming more parallel to the ground and getting longer.

Rear

Cut the rear so that it is 1 in shorter. Use the same procedure. Cut the top of the spring since it is a variable rate and the small oils locate the spring on the rear end. If you cut the bottom you may loose your spring.

 

One coil on the TA/Z28/ws6… front springs (BZX and similar codes) is about 3” drop in ride height. As the spring rate gets softer (say base V8 firebird/RS…) then the amount of drop from cutting one coil drops. Looking at a set of late RS F41 springs (BXW) one coil looks like it would drop the ride height about 1.5-2”.

Rear springs don’t drop as fast when cut, and spring rate goes up MUCH faster. By the time you lower the rear by just cutting stock springs the rear spring rate becomes much too high and you end up with a bumpy, oversteering ride. I’d suggest cutting half a coil and getting rid of the top spring isolator (worth about a 1” drop)

 

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Do they make a spring kit for our cars that will drop the car about 1 1.5 inches? If so, what companies make such kits for our cars?

 

They eibach pro kit springs are advertised as a 1" drop in their dealer catalog, but I don't know what car they measured them off of (ex, early 3rd gens had a really tall ride height from the factory, probably 2” taller then the later IROC/GTA’s, and some of the RS’s out there sagged real low very quickly).

Personally, I feel that the eibach pro kit springs sit a little high, but in a practical location for most people that are worried about dropping the car too much.

 

WTF RTFC, do you just make your **** up? I understand that you've had some luck with this on your car, but as far as I can tell it was probably a bunch of dumb luck and trial and error.

Frequency depends on spring rate and load. The length of the coil has nothing to do with it (well past the fact that a longer coil with the same diameter will have a lower spring rate and a lower frequency). Open a physics book and look into spring rate/spring constant and harmonics.

FWIW, the higher the suspension frequency the more dampening you need to acceptably control the unsprung weight and the less comfortable the ride will be (forget the jarring of the stiffer suspension, the human body is only happy moving in a specific frequency range, make it too low/slow and it tends to get “seasick” make it too high and you feel like your brains will rattle apart). As part of this conversation, basically, increasing spring rate is there to do 2 things 1) hold the car up at a ride height that will maintain acceptable suspension geometry, and 2) once 1 is accomplished you often need to add more spring rate to control the unsprung weight. Past that it’s all about suspension geometry, antisquat/antidive…

The ratio of free height to compressed height for one spring has nothing to do with what will happen with another spring. That ratio depends on number of free coils vs spring rate. Two springs can have exactly the same ride height and spring rate and be completely different, one could use a thinner wire with a shorter overall length (less coils) or with a thicker wire and longer overall length. Cutting the same amount out of each one of those springs will have a drastically different effect on rate. Ride height is largely dependant on the free height vs the spring rate vs the load when installed

And before you even think about giving the “well, they’re in the same general range,” I’ll stop you. There were at least 14different front coil springs (and I think 6 or 7 rear springs) used from the factory, not only where there specific “this is roughly the spring for this suspension” but there were usually 2-3 springs used for each suspension based on options and what the car ended up weighing as it rolled down the assembly line. For example, a mid/late WS6 car could have come with 3 different front springs, 2 different rear springs (3 if you count the similar Z28 suspension package, generally the chevy’s came with a softer rear spring rate for the same front) and 2 different F/R sway bars in at least 3 different combinations, and the actual spring design was dramatically different. For example, a typical WS6 spring had 4.333 free coils, a typical earlier TA spring had 4.667 free coils (and a 2 in taller ride height but the same wheel rate), and an F41 camaro suspension had 6.333 free coils. The lighter cars, especially the base model camaros had even longer (free height) springs, and in most cases they sat at the same compressed height.

FWIW, I tend to like front springs in the 900lb/in range and rear springs just short of 200lb/in on lowered V8 car with softer sway bars then most use (I don’t like the heavy WS6 bars unless you change the location of the roll center of the rear suspension downward, which almost no one has done or is willing to put the work into to do)

 

So, to get my car down 1 to 1 1/2 inches, cut 1/2 of a coil off the back and then just remove the front top spring isolator? Will cutting the springs and removing the top coil isolator cause my car to handle better or worse, or the same? And what is the best way to get the front spring out? I have removed the rear coils out when replacing my rear end, but I have never messed with the front coils.

Once again, Thank you all for your help!

 

In just the back, try removing the isolator and replacing it with a few inches of heater hose pushed over the end of the spring. That should get you down about 1" without doing anything that's not reversible and it should only take you 10 min or so to try. If that doesn't cut it try 1/4 coil at a time. IMHO, more then half a coil out of the rear springs will leave you with too stiff a rear suspension for most people/cars.

Front springs, jack the car/jackstands under the frame, pull the wheels, put a shop jack under the spring pocket in the control arm with enough pressure to relieve the load on the pivot bolts, pull the pivot bolts and lower the control arm, pull out the spring (with longer stock springs it will still be slightly wedged in the spring pocket, I usually just pry it out with something about the size of a broom handle, there isn’t much force on it at that point. If it makes you nervous loop a piece of chain through some of the lower coils and around the control arm to hold it just in case.

 

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He's just jealous because he doesn't have a V-6

 

Heh… funny… Did you check the dates on some of that? I believe that the only update that any of that has had since ’99 is that I added the one line about the 83 TA being destroyed in Hurricane Isable. For that matter, if I had any problem with those pics or with those cars I wouldn’t have posted pics of them in other threads in the last day or so.



Do you know of a book that has the information that I posted? If you do I’d love to see it since it would save me a lot of time

FWIW, most of the spring information that I have is based on a printout years ago of GM’s own production codes that I got from Low-tech who can get some of this info through his job (damn, Tim I bet that you didn’t even think that I still had that, I got it from Mike when I borrowed the Phun book from him in the early 90’s), and the actual numbers, free height, free coils, wire sizes as well as calculated and measured spring rates is info that I measured and put together myself.

I’m sorry if you’re wrong with both your technical and empirical information. I tried being nice about it the first couple of times that I corrected you on this board and I’m getting tired of dancing around to protect some idiot’s ego.

Man, where exactly did I talk any smack or direct any kind of threat at you? “Obessly overweight?” Heh… I’m 6’4, 291# and I wear a size 58 suit and 36-38 pants. I could stand to loose a few lbs like almost everyone, but it’s not that much…. If you want to take proverbial shots at me I would suggest you come here so I can end it quickly and quit wasting everyone else’s time.

I’m really confused here. Am I supposed to be terrified of you? Cower in the light of your vastly superior intellect? Run from the mountain of empirical data that you’re presenting? Be crushed by your overwhelming ego and charisma?

How about you just post something correct and on topic or crawl back under your rock?

 

OK, enough! This is silly and I have read on this fourm many times, people getting into bench racing/bench fighting Enough! Heck, I just wanted to know of an easy and inexpensive way to lower my Z 1 to 1.5 inches AND if the performance will change? Sorry if I started any fires.

 

Hey Crossfire, you win in the expert game. I'll retract all my posts here and you help him. Its on your hands to give him reliable factual options on how he should spend his hard earned money.

 

RTFC
I wish you would have not deleted your post I know nothing about suspensions and or lowering cars. I know a crap load about engines/trannys/supercharger/turbo's....but nothing about lowering the cars. I do know that there are a lot of different opinions about all matters and I like to hear all theories and ideas regarding such said topics. I really wish you hadn't deleted your post

 

Not your fault, you have nothing to apologize for. As far as that goes, I’m sorry for wasting some of your time and space here, but I was also getting very tired of personal attacks and the resultant pile of email with “can you help me with xxx, I don’t want to post on the board because of…”

Anyway, I think I answered the drop part, as far as performance, as you cut the spring, spring rate goes up, which is why I was telling you that you really shouldn’t cut the rear springs more then you absolutely have to because these cars have a high rear roll center and do not like a stiff rear spring rate, especially at lower speeds. Cutting 1 coil off of the rear springs makes them a good match for roughly 900# front springs. If your rear spring rate gets too high you’ll end up with oversteer, which is fairly unsafe.

As far as what I would recommend… well, as a bunch of us have already said, the eibach pro kit springs will lower the car exactly the amount that you’re asking for with no drama and no hassles.

 

TY!