Spring rates / coilovers / shocks

[Chris Corolla S]

O.K. a few more questions here.

I am narrowing in on my set-up (Tokico HPs, Ground Control coilovers) and I'm wondering how a non-adjustable shock will perform with coil-overs. Will running the springs at stock height be to tall for the struts? Will it be to bouncy when fully lowered? Will changing the ride height alot reduce the life of the struts?

If I go for custom spring rates, shaun sugested 3kg/mm would be nice and stiff but still good for street, but I have noticed that often the spring rates are different for front and back. Is this only for track or what? is 3kg/mm good?

[boroEF]

sorry, i miscalculated my spring rates. they are 5.6kg/mm front and 5.7kg/mm rear...and my car doesnt ride harsh(mind u, i am on 60 profile 14inch tires).

anyhow....since ur car is heavier than mine, i'd say 5kg/mm is a safe rate to try out. it's going to be more firm than stock, but wont be bouncy or harsh at all.

with regards to using coil overs set at stock ride height on non adjustable shocks.....it's all good, i wont be too tall for the shocks. those non adjustables can even be used at stock ride height with no problems-i actually think that they were designed for stock height.

will lowering the car reduce the life of the shocks? yes, it will...unless of course u get short stroke shocks...which are designed for shorter springs.

like i said before, check out H&R OE sport springs. 0.5inch drop and 15-30% stiffer than stock. i think that's something that u are looking for. these combined with say...tokico blues will last u at the very least 5 years easily.

[Chris Corolla S]

My car is heavier? Mine weighs 2,400 lbs man how much is yours?

As I said in the other thread acording to H&R's website I can only get the springs with 1.3 drop in front and 1.25 in rear from them.

I am riding on 195/60 R14s so no difference there.

[boroEF]

oops. i appologize for accusing ur car of being a porker.....
my car is 2500lbs

anyhow......5.xxkg/mm would be great for ur car thennnn! that with tokico blues...mmm

[Chris Corolla S]

So should I go with slightly softer in front? I usually see on Grand Turismo (I know ) that a slammed track car will be set at like 8kg/mm in front and 9kg/mm in back, but that's for a RWD.

Is it better to go softer in front to get more turn in and stiffer in rear to help step out the back? Like maybe just 5kg/mm in front and 5.5kg/mm in back or some shit. Or should I just get the same for both?

Oh, and don't worry about thinking my car is heavy. For the ZZE110, The manual S is the lightest of all the models, followed by the CE and then the LE, which in Auto trim does weigh significantly more than your car. But yeah, my version of the S is like "stripped down"
The '03 S's are just as heavy as the LEs with the CE manual being the lightest. That's why I think my car is just as fast or faster than an '03 because even though they have 5 more HP, it comes in at a higher RPM and they weigh like 200lbs more...blah
Anyway, about those rates and what not yeah...

[boroEF]

softer front would help, but the problem is that a 5kgmm front spring rate is already plenty soft. if you are concerned about swinging out the ass and reducing the understeer characteristics that your car has, invest in a thicker rear sway bar...that will change the yaw characteristics of the car's handling....

if sway bar will cost u too much money, try out 5kgmm front and 7kgmm rear, u wont be dissapointed

but my current 5.5 front and 5.7 or so rear with 14mil rear bar handles very neutral. i can get the rear end to rotate mid corner simply by lifting off the gas.... if i trail brake i can get the rear end to step out a tad. i think these rates are good enough unless you will be running some very sticky tires.

[Chris Corolla S]

Heh, I don't want no 7kg/mm on the rear....

I do want to get a thicker rear sway of course 9maybe front too). I will have to have it made or S/O from TRD Japan though. The other alternantive is getting a universal app. endlink/bushing set for my stock sway(s) from Energy Suspension which is looking good to me as far as price goes....
I wish I could find out how think my stock sways are... I need one of those caliper measuring doohickys....
So you kinda skipped my rate question... Do you think 5 in front and 5.5 out back would be good for me or are you saying 5 is to soft now?

I want to find out my stock rates to, that would help, know any sites for such info?

EDIT: is that 14mil your stock rear anti-sway bar?

[boroEF]

Originally posted by Chris Corolla S
Heh, I don't want no 7kg/mm on the rear....

I do want to get a thicker rear sway of course 9maybe front too). I will have to have it made or S/O from TRD Japan though. The other alternantive is getting a universal app. endlink/bushing set for my stock sway(s) from Energy Suspension which is looking good to me as far as price goes....
I wish I could find out how think my stock sways are... I need one of those caliper measuring doohickys....
So you kinda skipped my rate question... Do you think 5 in front and 5.5 out back would be good for me or are you saying 5 is to soft now?

I want to find out my stock rates to, that would help, know any sites for such info?

EDIT: is that 14mil your stock rear anti-sway bar?

no, 5kgmm will be fine. it's not soft. definately quite a bit stiffer than stock! i bet stock is around 2kgmm or thereabouts. it's rediculously low....

so 5kgmm front and 5.5 back would be okay..... and as for stock rates, i dont know where u could check it, but there's a method that i read somewhere about how u can calculate it...something about the thickness of the spring and how many coils it has...and the height or something anyhow....14mil is the thickness of my rear sway from OEM....i'd imagine your's is 12-14 if u have one.....give u an idea: EK SiR is 12mil(according to my bro anyway). integra R is 22mil <--- that's sweet

[Chris Corolla S]

Thanks so much for all your help with this suspension stuff Shaun!
Most discussions about springs and shocks in forums are about fender gap and shit. People are so concerned about acheiving "the look", they don't care about spring rates. I see so many people with like 2.5 inch drops on stock shocks. The car bounces every where but at least it hasn't got that fender gap lol. Anyway thanks without you I would have been talking to myself about this stuff.

PEACE
Chris

[Cor_LOW_la]

for a Corolla... 5-7kg/mm front and 4-5kg/mm rear will make you freaking happy...

i'm running TRD Japan setup with 5.5k front and 4k rear..

[Chris Corolla S]

Hey Car-low-la! That throws a monkey wrench in 'cause I was thinking stiffer in rear than front but now you are saying vice versa?!

What's the pros/cons of siffer front vs stiffer rear? I would think that you would want stiffer rear springs to counteract under-steer. But I guess if TRD has stiffer front rates there must be sumtin' to it.

More opinions please!

[Cor_LOW_la]

hehehe... sorry i didn't read...

by the way... don't make it too stiff on the rear .. your car will oversteer like no tomorrow.. and u're screwed when u oversteer on a FF car...

sth. like 5.5k front 5k or 5.5k rear will do... don't let the rear more than the front... don't forget you are running a FF car...

think dude...if stiffer in the rear is really gonna help the corolla's understeer problem ... why wouldn't the companies make them...

for stock i dunno... for TRD USA (Eibach) it's 3.2k front and 3k rear...

[boroEF]

Originally posted by Chris Corolla S
Hey Car-low-la! That throws a monkey wrench in 'cause I was thinking stiffer in rear than front but now you are saying vice versa?!

What's the pros/cons of siffer front vs stiffer rear? I would think that you would want stiffer rear springs to counteract under-steer. But I guess if TRD has stiffer front rates there must be sumtin' to it.

More opinions please!

stiffer front and softer rear=will keep the inherit understeer characteristics of the car but will still improve turn in response and majorly reduce body roll..u will be able to carry a higher speed in corners but ultimately, u will not acheive the neutral balance that u are looking for. possibly in a RWD setup u'd be looking for something like this, but if your goal is to reduce push and make the car handle neutral, i suggest having even front and rear rates, if not having a slightly stiffer rear. may i suggest test driving some cars with this setup and test driving some cars with the other setup that the other person suggested.

but let me tell u, my H&R springs were harder rates in the front than the rear(which is pretty normal for an off the mill aftermarket lowering spring), and i was mightly dissapointed with them.

car low la's car may be a different story since he has ample rear spring rates.... u may go his route and get a stiffer rear bar...but i find that with the OEM sway and 5.7 rear 5.5 front it is very neutral....i lift off the gas and the rear end rotates slightly....

[boroEF]

Originally posted by Cor_LOW_la
hehehe... sorry i didn't read...

by the way... don't make it too stiff on the rear .. your car will oversteer like no tomorrow.. and u're screwed when u oversteer on a FF car...

wrong, u do want stiffer rear rates on an FF car...why? otherwise the car would understeer like no tomorrow...

consider this: getting 8kgmm rear and 6kgmm front an an FF car....so mid corner u start to oversteer....is that a problem? no, because let's remember here; your car is FF....what can u do? simple: give it more gas...the car will naturally pull out of the oversteer and correct it's line..... in this situation u will carry more speed out of the corner.(car pushes less, means u are able to give it more gas without having it push as much to excecute the same racing line)

why do most aftermaket companie's manufacture stiffer front rates than rear? to keep the car understeering....reduce accidents and not have any law suit difficulties with people.

why do you think all automobile manufactures purposely make their cars inheritly understeer on the OEM setup>? to keep it safe, not many drivers know how to control oversteer.... but such a thing is sought after by driving enthusiasts.... i assume chris is a driving enthusiast, he isnt going for the mere looks, he's going for handling.

this is not to say that 7kgmm front and 5kgmm rear is bad rates...it is good, but i firmly stand by my suggestion as i have tried both setups and prefer stiffer rear rates more for the reasons that i have stated...

a stiffer front rate than rear benifit:
quickens turn in response
compensates for the heavier front weight distribution
possibly helps with traction on initial launch
safer

disadvantages:
will still understeer unless a thicker rear sway is used/removal of front sway
will not be able to carry the same speed through a corner as a more neutral/oversteering car would

a stiffer rear rate than front benifit:
reduces push
enables user to acheive a more neutral handling characteristic without having to buy a thicker rear sway
able to retain front sway while still handling neutral

disadvantages:
more dangerous in the wet
oversteer scrubs speed when not used correctly

the stiffer rear rate is a proven suspension setup and is commonly used by the speed vision speed challenge cup FF cars...go to their web sites and check out the specs on those cars. virtually all of them run higher rear rates and thick ass rear sways.....IMO, this setup utilizes the "beauty" of FF: lift off throttle oversteer.....u simply need to control how much gas u give it midcorner and u are able to change how much it is steering without even using the steering wheel.

[boroEF]

i posted something useful for once