bitkahuna

iTrader: (20)

OK guys, I've done searches but can't find an explanation as to what makes coilovers better than separate springs/shocks except for the adjustment factor.

Anyone care to educate me? Much appreciated.

rominl

iTrader: (4)

well, if you think about it, you can get a good set of springs and shocks, but if you talk about true performance, it's the combination of the spring rate and also the stiffness of the shocks. putting a stiff shocks with soft springs are bad, but stiff shocks with very hard springs might not be a good thing as well. you need a good combination of both.

now with that in mind, would you get a good performance setup with the a certain brand of springs with another brand of shocks? it's possible, but imho it's not as likely.

the thing about coilover is, it's all from one company, they have their own r&d doing all the research about what spring rate with what stiffness of shocks, etc.... that's why when you get the coilover, say my tein HA, it's stiff, and it's good for track. and above all, you can adjust height when keeping the performance range of the setup, that's soemthing you can never get from springs/shock setup

bitkahuna

iTrader: (20)

Thanks rominl - very informative. Some more dumb coilover questions so bear with me.

I believe a coilover is actually two interleaved springs wrapped around a shock, is that right?

Also, you have the Tein HA which is a very popular coilover - did you have a (non-stock) spring/shock combo in there before you went to the Teins? If so, how did it compare?

Is a coilover in general lighter than a spring/shock combo?

Any other advantages to coilovers?

Is it true that there's separate stiffness AND lowering settings on coilovers?

Finally, you have the HA's, but have you even been in a GS with the Tein CS coilovers? I know they're softer, but I was wondering where their stiffness is, say in comparison to a typical after market spring/shock combo.

rominl

iTrader: (4)

no problem man, anything to help

well i don't exactly know the two interleaved springs. on my coilover, right about the spring mount, there is one very short springs, and then the main springs. is that what you looking for? i am sure for the flex it's a totally setup though

yup i have the HA. too bad i went directly to coilover and didn't get any springs/shocks beforehand. one thing you can do is to talk to jawnthen about it coz' he had springs/shocks before and now having the HA. what i can tell you is my experience with my gs4 and my acura tl-s. the tl-s i changed the springs and stay with stock shocks and it was some improvement already. when i got my gs4 the ride was absolutely way worse than my tl-s so i got the HA very soon afterwards. BAM right after intall the HA already outperform the setup on my tl-s already by a mile. so it's that good. i sat in jawnthen's car before (when he had the springs/shocks and trd sways), i think my HA setup without the trd sways at that time was able to perform about the same already

not sure about the weight though, very good question. i never able to weigh it myself... but if you compare my HA setup with the stock springs/shocks, yes, the tein setup seems to be a bit lighter

yes, at least for tein HA there are totally separate settings on stiffness and height. i have 16 clicks for my stiffness and it's done at the top of the strut tower (access from engine bay and trunk). for height i take off my wheel and do it along the shocks (you can see my DIY). from what i can tell, staying with the same stiffness clicks but adjust the height have SLIGHTLY effect on the overall stiffness (if i lower the car more it's stiffer), and i heard that's corrected in the flex system

no i have never set in a car with CS before, but from all the people with the CS setup that the ride could be exactly the same as the stock setup

D-MAN63

Bit, I used to have the H&R w/ bilstein shocks combo and it worked fine for me, but the only reason I went with TEINS is because I wanted a slightly more aggressive drop. With HA's on 0/0 it is definately (for me) softer than the H&R's. I have them at 8/6 and it is slightly harsher than my spring and shock combo. If I had to do it all over again, I would go straight to coilovers no doubt about it!

bitkahuna

iTrader: (20)

DIESEL - thanks... maybe I'll get some at some point... they definitely sound like the right way to go.

RON430

bit - I can agree and disagree with some of what has been said here but fundamentally, whoever sets the component up will shoot for their goal (either set individually or in committee). The stock Lexus suspension is what Lexus thinks is appropriate (not trying to justify it, just saying they have engineered their approach). The coil overs do have a shock specific spring with adjustable height and maybe shock dampening adjustability, and maybe adjustable for both jounce and rebound. They will still work as intended by the supplier and it might be what you want, it might not. A whole lot of this site is about modding and we mod for different reasons, looks, ride/handling, speed, etc. When the coilover mfr designs a shock he gets to pick a spring to go with it but is it going on a car with stock or upgraded sways? Is it going on a car with 55 series 16s or 35 series 19s? Does the car have the stock chassis or have braces been added? All of this adds up to the ultimate result and I wouldn't say that just going coilovers is superior to non adjustable shocks and springs. But there is the adjustability in ride height and possible shock valving. I am a huge fan of bilstein but their coil overs for the GS are only available in adjustable ride height, not shock valving. This doesn't really bother me as I seem to always like what bilstein comes up with for valving but I can certainly understand the value of having adjustability. For me, the TRD sways, bilstein sport shocks, stock springs and stock 16s give a very smooth and very controlled ride. Might be interested in a little drop but that is for looks only, and the first time I bash a parking stop or hit on a speed bump and I would probably screw things back up. Just wanted to say that you can hit the balance you want either way. The coilovers might be less costly with adjustability and they might not, for example if you don't like the spring rates or the adjustability range provided on the shocks. In the early days of Trans Am we had such ill handling cars that we just went stiff with everything. Eventually we found out that if you have 1200 lb springs on the corners, your sway bars don't work because the body never sways. So, we started loosening spring rates up to keep tires in contact with the road and started figuring out how sway bars, and Watts linkages, and shocks all work together. And that was a lot easier on a race car because you could always look at lap times to see how you were improving because that was the whole point of the exercise. On a street car, the street changes (boy does it change) and our moods change, and our goals change (sometimes you want to tear it up, sometimes you just want to do an A to B in as much serenity as you can get). I still think coilovers are intriguing and definitely worth a look but I am also aware of some of the problems that guys have with vibrations and uneven tire wear with mods that inevitably include dropping. I can't say that I have seen any of these problems on either of the two GS's that I have now so I am not quite so sold on the benefit of the increase in "looks" relative to the potentia side effects from dropping. That certainly wasn't meant to be a flame because I am a big fan of modding but there are some things going on that I just can't explain. For example, the guys who swear that the TRD sways give a harsh ride. I believe them, but it is the sways in combination with something else because with the stock springs and bilstein sports, there is no noticeable degradation in ride that comes with a dead flat cornering stance. But then the suspension is a total system, not just individual components. Long winded two cents.

bitkahuna

iTrader: (20)

Thanks for the feedback Ron. It's helpful and has good perspective.

A suspension is certainly more than springs and shocks or coilovers.

I don't know anyone in Atlanta who has coilovers, so it's hard to know what they would be like.

DoubleWhoosh

Well, here's some other information that might help (or maybe cause more confusion! )

The term coilover refers to the physical placement of a spring around a shock absorber. Older cars for the most part didn't have what is referred to as a "strut". Most had some coil springs on a-arms and/or leaf springs or some combination thereof. The shock absorber was usually separate and connected some suspension arm or axle to the body or usually the frame somewhere.

Newer vehicles (in the effort to save time, money and weight), use what is usually referred to as a McPherson strut assembly, which contains the whole shock and spring in one assembly. Many times this is also an integral part of the suspension, rather than just a separate component that controls height or damping.

In the technical shock world, any shock with a spring on or around it is referred to as a coilover (simply by definition of the word itself).

Now, most aftermarket replacement springs use the existing shock or strut, or a replacement shock that is designed to be a direct replacement. This is fine, especially so if you can find a shock that is matched in damping to the spring that you are using. As mentioned above, there are so many variables with other suspension components, tires, plus user preferences and intended use, that it is pretty hard to cover them all.

This is the beauty of so much stuff on the market, that one can choose what is best for their application. Especially so nowdays with the resource of the internet, where you can exchange information and experiences to help guide you in the right direction.

Now, most race cars, both road and drag have what they refer to as a coilover setup, which has a spring around a shock, but with the added twist of a threaded or adjustable spring seat. This is used sometimes to adjust vehicle height, but also to change spring rate. On a race car, optimum suspension settings are very critical, and this allows the user to make fine adjustments for corner weight, shock absorption, plus usually damping adjustments as well. This is where the more common "coilover" term comes from.

Now some aftermarket companies developed shock and spring setups for street cars (or weekend race cars, or stock-type race cars), and tooled shocks with adjustable spring seats, and specific springs. These of course don't work with the stock parts, you simply remove the whole stock assembly and replace it with the new shock and spring setup. This of course is very expensive to tool and produce, as virtually everything has to be made from scratch. In the world of aftermarket parts, this is not too cost effective, as most people are not willing to spend the $1000 to $3000 that these cost. It takes a serious enthusiast to spend this money, but there are added benefits beyond normal springs and shocks...

The stock shocks are a given length, which is fine for stock use. When using lowered springs, of course the car is sitting lower, but that also causes a problem with losing some of the original suspension travel. Other than the body of the car hitting the ground, the tires hitting inside the wheelwells, or the control arms binding up, the only thing controlling how absolutely low a car will go is usually the shock body itself. Toyotas have a tendency to have longer shocks than some other manufacturers, so lowering them more than 1-1.5" is usually the most you can go. Of course this still causes a loss of suspension travel from static ride height until the suspension is bottomed out due to the length of the original shock. This is something you cannot escape no matter what. This is where the aftermarket coilover setups can be much superior...

These are designed with the shock and spring together, and are also intended for use in lowered applications. Why is this important to us? Because they will make the shock SHORTER than the stock shock. This allows the suspension to travel more before bottoming out. This also allows the shock to stay in an optimum portion of its stroke during normal use, which is something that the stock shock doesn't get to do.

There are very few manufacturers that are willing to make a direct replacement shock that is significantly different from the OE unit, probably due to compatibility issues or what not. This is where the coilover setups reign superior, and are also able to ride better at the same or lower heights. It is when the suspension bottoms out on the bump stops when the suspension provides a "bad ride."

Some Koni and Bilstien shocks also have adjustable spring seat shocks, which have grooves milled into the shock body with a c-clip that can be adjusted to change the height of the spring seat. This is basically the same thing as the threaded adjustment seats, just without the infinitely adjustable height adjustment. But once again it all comes down to the length and design of the shock itself.

Todd Matsubara
TM Engineering LLC
www.tmengineering.net

bitkahuna

iTrader: (20)

Awesome information Todd, thank you very much.

Mods: Maybe a good thread to sticky?

RON430

Hey Todd,

I figured bit had gotten all the basics down but one thing you mentioned is kind of curious to me. It is:

"Now, most race cars, both road and drag have what they refer to as a coilover setup, which has a spring around a shock, but with the added twist of a threaded or adjustable spring seat. This is used sometimes to adjust vehicle height, but also to change spring rate. On a race car, optimum suspension settings are very critical, and this allows the user to make fine adjustments for corner weight, shock absorption, plus usually damping adjustments as well. This is where the more common "coilover" term comes from."

In most coilovers I have seen, the upper spring and shock mount are coincident and tie to the suspension. The lower spring perch is threaded around the shock body while the lower shock mount is the other point affixed to the suspension. To adjust ride height, the shock body is threaded into or out of the spring, bringing with it the lower suspension attachment point. But the spring rate isn't affected by this adjustment. How do the units work where they adjust spring rate? Far as I know, the racers still change springs for spring rate. They may be able to make some minor affect by adjusting preload with something but I haven't seen a coilover setup, street or track, that let's you adjust spring rate. Is there something different out there? How does it work?

DoubleWhoosh

Yes, the preload adjustment was what I was actually referring to, but it's mostly in drag racing that it's used. Most commonly it's to make the spring tighter when the car launches, a lot of time to control corner weights. The height is then readjusted with the brackets and mounts on the car.

LS400

A very informative post.

Sticky done.

rominl

iTrader: (4)

oh my god!!!!!! this is one of the most informative posts i have seen here, todd you da man. you said every single details we need to undersrtand abot all these suspension stuff!!!! i am speechless!

GSTRANCE

Bit, I am not sure of the guys name, but he came to one of our meets.I wanna say it was the nov. or dec. meet maybe.He came down from NC I believe.He had the Bilstein PSS coiovers on his GS.And he was running a similar wheel/tire setup as you.He took me for a ride, and given the only thing I could compare the ride to was my Eibachs , but the car rode and handled amazingly.and that was his only suspension mod if I remeber correctly.No braces or bars.I havent heard of many owners of these Biltein coiovers, but they are something I am gonna investigate when the time comes.