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Lowering Springs misconception

37K views 59 replies 26 participants last post by  xmjsilverx 
#1 · (Edited)
I believe it's time to just flat out explain why lowering springs do not improve your handling. It infact should worsen it. The rate of your stock springs and your stock shocks were made to work with each other. The fact is that the stock shocks were not designed to handle the increased rate of an aftermarket spring. This also causes more wear and tear on the stock shocks. The wheels on the car will oscillate in a manner that will actually reduce wheel contact with the ground. The more the springs are compressed the larger the oscillations will be, thus meaning the harder you push your car, the worse it will handle.

What, you want proof? Okay, here it is. This following is an excerpt from the book Training WRX 2nd Edition by Nick Warne. These are track times provided by Whiteline's Project REX I and II. NOT QUARTER MILE. Car was required to do atleast a minimum of 4 laps, more if the driver felt he could do it faster. Professional driver running with Falken GrB's 205/50/16 tires with moderate tread.

Vehicle: MY99 WRX sedan

Session 1
Conditions: Steady light rain
Suspension: Stock
Seconds: 0.00 (base)

Session 6
Conditions: Light rain, standing water
Suspension: Stock w/ KCA319 Anti-lift kit
Seconds: -0.79 (.79 seconds faster)

Session 8
Conditions: Light rain, track drying
Suspension: Stock w/ same ALK and aftermarket lowered heavy duty springs
Seconds: -0.23

Let's recap. If the ALK provides a gain of 0.79 seconds, that means the lowering springs made the car atleast a half second slower. Keep in mind this is also while track conditions were improving.

... I'm sure someone will ask later, so I'll just say it now. Larger rear sway bar alone provided a full second faster track time.


It's plain and simple, if you want it for cosmetic reasons, there is nothing wrong with a set of springs. It's cheap and accomplishes your goal of eliminating that crazy front wheel gap. Most people probably never push their car hard enough under daily driving to feel the effects of it. Just be mindful that your shocks will probably go sooner than with stock springs.

To lower a car properly, you need to either match up the spring with a set of shocks, or do a full blown set of coilovers.

Also check out this write up. They did an excellent job. http://forums.nasioc.com/forums/showthread.php?t=1030221
 
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#28 ·
Struts are a wear item- the oe springs will wear out the oe struts. Depnding how and where you drive will determine how long they last. Adding a stiffer spring will accelerate that wear- the STi springs are stiffer. They also lower lsightly over the WRX springs ~ 10mm- so that adds a little to the wear equation.

Having said that- the STi oe springs are very, very similar to the WRX pinks springs in both spring rates and lowering. I think these will work fine w/ the oe struts, strut life won't be as long as w/ oe springs, but you will reduce roll and dial out some undesteer as well.

Stiffer springs will stiffen the ride, as will firmer dampers- that's one of the tradeoffs of going to a higher performing suspension. How much stiffer is subjective, I find the oe WRX setup very wallowly- others find it find pretty firm as is :)
 
#29 ·
#31 ·
Big Sky said:
There will be a product on the market soon that will reverse the negative geometry effect of lowering- it simply provides a spacer to lengthen the lower ball joint so the lower arm goes less parallel. It will also provide a spacer for the tie rod so bump steer doesn't then become an issue.

This will allow you to have your cake and eat it too :)
So any word on when these certain products will be available, and by who? Suspension geometry is a very interesting buy a challenge for me. Mostly because I learned about static physics in college (building physics stuff). I have an 06 and I want to put H-techs on my stock struts. I think that I should be ok with H-techs on stock shocks, but with this special kit you mention above my suspension geometry may be better off.

What do you think Big Sky?
 
#32 ·
I think you'll be fine w/ the H techs. The kit is being pre-sold on nasioc by Turn In Concepts- includes a balljoint spacer and a tie rod end spacer- it's pricey at ~ $400. If your a competive driver (and this a allowable modification) it would be worth the $. For a daily driver, probably better places to spend the $400.
 
#33 ·
I recently purchased, from my dealership and installed myself, STi Pink Springs (made by Eibach for Prodrive, endorsed by STi). The bottom line is handling is improved, the car is slightly lower AND the dealership confirmed that becuse its an STi part, my stock struts are still covered under warranty. This appears to be the lowest risk option for new WRX owners under warranty looking for tighter handling.
 
#34 ·
BizTerp said:
I recently purchased, from my dealership and installed myself, STi Pink Springs (made by Eibach for Prodrive, endorsed by STi). The bottom line is handling is improved, the car is slightly lower AND the dealership confirmed that becuse its an STi part, my stock struts are still covered under warranty. This appears to be the lowest risk option for new WRX owners under warranty looking for tighter handling.
You may feel that your handling has improved, but I assure you it hasn't. That was the point of the whole thread and the debate.
 
#36 ·
This doesn't make any sence to me. My 06 used to push bad in the corners espeacaily when trying to power through. But after I lowered it with just springs it now is more responsive and makes the steering more percise also the pushing in the front is almost totaly gone. And it doesn't lift in the front when your launching and that means the power you were losing lifting the front of the car is now translated into forward motion.maybe the tests done on the older body style would have differnt results on the newer body styles. I hope I'm not totaly wrong did anybody else notice a difference when they lowered there car?
 
#37 ·
you changed the spring weight.... that improved the way the car handled.... i i disagree with what is being said here.... if you lower a car and make the right changes to it camber ect you lowered the center of gravety.... with stiffer springs and anit roll bars you kkep the weight of the car spread out ove the car evenly when cornering hard makeing all 4 tires work.... this is coming from many years of racing.... there is a reason that racing classes set a min ride hight....
 
#38 ·
There is more to lowering the car than then lower the center of gravity- lowering the cog is "good". With our cars as you lower the cog does also lower BUT (and this is a pretty big but) the roll center migrates downaward as well and gets further from the cog. The further you lower the further they get apart (the roll center lowers faster than the cog). That distance between the two is the roll couple- the longer the roll couple the more easily the car will roll. Increasing roll stiffness (through springs and sway bars) combats some of this effect. Your also degrading the camber curve- this can be combatted w/ more static neg camber, but there are disadvantages w/ too much neg camber- namely increased braking distances and tire wear.

Many "race" cars are low as they are allowed to move the suspension pickup points, also double wishbone designs are much more tolerant to lowering than MaC Pherson's are.

Nobody's saying don't lower- just be aware that it's not all gravy and you can lower to the point of degrading performance.
 
#40 ·
if you mean "tune" as in changing the roll centers via suspension geomtery (lengthening ball joints/moving pickup points/etc)- then yes a lowered car would be quicker around said track

if you mean a set of crappy lowering springs that "slams" the car vs a set of well designed springs that lower minimally (or even none at all) = then you'll see a different result :)
 
#46 ·
Big Sky there are two ways to look at this.... look at it this way there's the engenairs way to look at and there's a mechnics way too look at it.... in big race opps the engenairs give there data to the michincs they look it over try some things then based on how the DRIVER feels in the car they make adjustments.... you lean way too much on what engenairs say and too little on what you feel in the car....
 
#50 ·
I have prodrive lowering springs on KYB GR2 struts, and I love them, they have noticeably improved my handling over stock springs and OEM struts. But, I followed the golden rule of lowering springs.. As whitelines own sites says, and I quote..

"Our springs WILL make your car handle better if matched with appropriate shocks"

This is the only thing one need consider when looking at springs IMHO... the rest just reads like a commercial for coilovers and whitelines 'other' suspension parts for which they are more well known and established. Especially sway bars.. and imagine that, better time with just their ALK, and that nice little blurb about a second gain from JUST a sway bar. $$$$ Cha-Ching!

Everyone is selling something, and I rarely trust 'studies' conducted by manufacturers that then suggest their 'other' solutions as 'better' alternatives.

Just my 2 cents.. match your springs with your struts, and you'll be fine.
 
#51 ·
indeed one has to match the springs w/ dampers, but the lowering spring still changes the geometry (lowering the cg AND the rc)- this is nothing the strut has any influence over (unless one fabs up different spring perches :))

regardless of damper, the message remains w/ a Mac P setup you can go too low and hurt handling
 
#53 ·
Yes... I see what you mean. This topic has outgrown itself I must say. Basically, the reason I started this thread because there was a big flood of posts concerning lowering springs and the assumption regardless, handling would be improved.

The change in geometery was my biggest concern when I first got into it. My co-worker and I had a big discussion and the solutions were not pretty. A little more involved than most would be willing to go. Mainly why I didn't mention it.

But he is right, there is MUCH to be considered, and much I don't understand myself. If BigSky is willing to work with me, I'd be more than happy to update this thread. ;)
 
#54 ·
I like where you are going with this Vew. Im trying to learn and understand suspension a little better myself. Like the best ways to do it, best combinations, and what affects what. I second Vews motion, lol.
 
#55 ·
Lowering springs aren't "bad" per se, in fact they can improve performance (significantly in some cases), it is important to realize (particularly w/ a MacP setup) that lowering springs can also decrease performance in some cases.

Lowering is "good" because it lowers the center of gravity (cog), where things go haywire is w/ a Mac P strut as you lower you lower the roll center (rc) too- this don't lower proportionally, the more you lower the further the cog distances itself form the rc. The distance between the cog and rc is refered to as the roll couple- think of it as a lever- the shorter the lever the more the car will resist roll, the longer the opposite (refer to the diagram I linked earlier). Ideally you want to keep the lever short as possible, thus the caution of over lowering and the potential for decrease in performance. Obviously spring rates play a role as well, the stiffer the more resitant to roll- so as you lower you want to insure that spring rates go up.

I could go on, but basically if you keep the lowering moderate, increasing the spring rates as well- you will see an increase in performance. Don't keep the lowering moderate and/or increase the spring rates you could very well see a decrease in performance.
 
#56 ·
I could go on, but basically if you keep the lowering moderate, increasing the spring rates as well- you will see an increase in performance. Don't keep the lowering moderate and/or increase the spring rates you could very well see a decrease in performance.
And the "I assure you it has not" post was in regards to a set of SPT Pinks - which lower very mildly and increase the rates noticeably (since they are practically the same as the USDM STi springs) - I thought that was odd ;)

john
 
#58 ·
Ok, I know I am new here but I feel like I have to chime in. I am a mechanic and not an engineer so if there is a suspension engineer here please tell me if I'm wrong. How in the world is a lowering your car an inch or less going to damage your strut? A strut does not need a certain spring rate to work. A strut is designed to control spring oscillation. All the strut is is a cylinder filled with oil and a piston with orfices for the oil to flow through. There are absolutely different rates of dampening but this is going to effect your ride comfort and will not make a strut work with a spring. As long as you don't over compress or over extend your strut, a lowering spring is not going to harm it. Controlling your spring oscillations with an adjustable damper can improve your handling and/or ride comfort but it is not necessary. The arguement over lowering springs having to be stiffer to work is a bit of a misconception. They do make progressive rate springs which means at the beginning compression of the spring the rate will be similar to the stock spring thus a stock feeling ride. As the springs compresses further the spring rate will become stiffer to keep the strut/shock from bottoming out. So if you hit a pothole you are going to feel like this new lowering spring rides rougher than stock but under normal driving it should feel very similar. I am not going to argue much over faster track times because that claim does not mean much when they give you very few details about the suspension setup.
 
#59 ·
That was a very old post. There is more discussion further in the thread talking about some of the details you mention. My understanding has grown a lot since I wrote the OP. The biggest thing I wanted to get across was that just because you slap a set of XYZ lowering springs on your car, doesn't mean you're going to get improvements on handling, if any (which was the general newbie mindset). There's a lot more to it than that. Perhaps it's time to un-sticky this thread. Thanks for the input.
 
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