Suspension question 2004/Stock suspension

I need some info about stock 2004 sti stock suspension. Now that the roads here have frozen up and are shitty I have noticed that when going over horizontal cracks that are evenly spaced I get allot of pogoing and bouncing that just drive me nuts. It seems the suspension is getting overwhelmed and was wondering if there is anything I can change that would allow the suspension to cope with high speed bump control. My next mod will be coil overs if this will only exacerbate this condition I may have to go a different rout. Any and all suggestions are welcome.
 

IGOTASTi

System Operator
Staff member
Mine did the exact same thing as yours did.
 

HolyCrapItsFast

Drinks beer!
I can say, for bumps or imperfections in the road, that coilovers will not help at all with that. If anything you need to soften the suspension. Any mod you do will usually be geared toward handling and for HPDE where road surfaces are almost perfect. For street driving nothing beats the stock suspension with a good set of sway bars. If you have to lower it and are using it on the street mostly then I would suggest stock STi struts with lowering springs.

The first thing you can do though is to get a four wheel alignment and also look into changing your tires more than anything. They have decent performance touring tires with softer compounds that are ideal for daily street driving yet are still good for the occasional auto cross.
 
I was thinking about a dual rate spring and adjustable coil overs I just don't have the info I need to make an informed decision. I am now very happy with the power due to the Guy above (and he isnt even done with the tune). I understand that there will be some sacrifice with comfort but there will be an increase in performance and control, I just want to make the right decision the first time and not have to worry about doing it over. Good point Holy I will be adding tires to the list of possible changes. Any one have info on tire PSI changes and how it reacts with the center diff? Lets say 28 psi in the front and 34 in the rear will this cause wear on the center diff (don't worry I have 31 psi all around)

Would tearing apart the struts and regreasing them help? the rear do have the all time loved clunk.
 
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Grinder34

Track Monkey
I haven't been on the stock suspension in years, but i do remember a fair bit of discussion about factory "bobble head."

Coilovers are the most expensive way to fix any problem, but they can fix almost every problem.

Sways dont help with anything in a straight line. But with a coilovers you can control and easily/cheaply change spring rate and damping settings. With 2+ way shocks you can have even more control over all behavior...but you can also screw up the behavior just as easily. Sometimes the fewer "knobs" the better.
 

IGOTASTi

System Operator
Staff member
Try running 32 in the front, and 30 in the rear. That seems to help a little.

Also when I was on stock suspension I got the white line sway bars, and end links, and that seems to really help. The sways really changed it. I also went to a custom coil over setup for my STi, and it rides like a dream, but wasn't cheap.
 

Spamby

Meat Product Toy
For what it's worth, I noticed a large improvement over the stock struts/springs vs. my coilovers. Though, my coilovers aren't the typical small spring, high pound rated type. The springs are progressive and they have a softer spring rate... I think 300-400 range. The shocks seem to do a lot better job of controlling the car over less than perfect roads. These seem to be geared more towards a street driver more so than track car.
This is a GR and may be different than the GD and still yet is my observation and may not be typical of others.

Lower psi in the front can cause more of an understeer situation and make steering slow and a bit squirmy. Higher in the front vs. rear will help the car oversteer a bit and help steering response.

Dunno what the limit would be but i would think the C-Diff can handle some variations. Though 6 pounds f/r difference may simply just cause some adverse handling. Unless you have some special requirements i would keep the differences a bit closer.

Nothing really to grease on the strut other than the little bump stop.
 

IGOTASTi

System Operator
Staff member
Grinder in the turns my sways really helped my stock suspension, but once I went to my Feal coilovers my STi changed to a different machine. Mine was also custom built for me.
 

Grinder34

Track Monkey
Grinder in the turns my sways really helped my stock suspension, but once I went to my Feal coilovers my STi changed to a different machine. Mine was also custom built for me.


Agreed.

But the original question seems to be more geared towards straight-line highway type situations. I could be reading it wrong, but i got the impression he wasnt asking about cornering, but rather about comfort over high speed bumps.

To that end, you'll need to address the strut/spring combo. Yes, coilovers will be the ultimate solution, but there are probably cheaper ways of solving the problem. He says his next mod will be coilovers already, so...do it! Coilovers are a very good next step.

Remember, with coilovers YOU are responsible for setting up the car. Its very possible to over-damp or under-damp the springs by fiddling with knobs too much. But its a good learning experience to tweak it every morning until you get it where you like it...but you may not fix the problem over night.
 

Spamby

Meat Product Toy
Grinder,

Swaybars actually can asist a car in a straight line. How they act on a corner car with load shift, they also act in the same way in a staright line. Even in a straight line, the car does pitch from side to side, thus loading and unloading each side, over road imperfections. Stouter bars and mounting tabs adjustable will preload the suspension a bit and help the cars pitching over undulations on the road surface. A small degree and especially when compared to cornering, they still yet help stabilize the suspension a bit in a straight line.
 

Grinder34

Track Monkey
in a stright line sway bars should have minimal effect. It's true, under accelereation the motor torques causing slightly higher loads from side to side, but i think it's negligible compared to spring and dampers. But the only thing swaybars do it attach left and right sides, so under *most* straight line conditions there would be almost no contribution between 0mm swaybar and a 99mm swaybar. That's assuming the highway is symmetrical and bumps on the left happen on the right, but i think thats a good highway assumption.
 
Just want to get your guys thoughts on these http://www.racinglab.com/megan-racing-spec-rs-coilover-010.html. I am now on a suspension modding quest... Holy will do his magic (which he has done outstanding!) hopefully his tune will sedate the speed freak in me for a little and give me time to make my car turn and burn.

And god damn it Grinder I need a PHD in physics to read some of your posts (outstanding information). :tard: I probably shouldnt be drinking and reading.

Some more information- My car will not have any track time it is strictly a DD/spirited driving, I will be happy with 300-350 hp (for a little bit) but handling is my top priority right now. My plan as of now it pp stock exhaust manifolds, crossover pipe and up pipe. I'm going full bore on the handling side of things though I just want to make sure not to fuck it up the first time.
 

Grinder34

Track Monkey
Do you know how to read a shock dyno?

So honestly, its one of those things like engine mods: If you're the first person to do it, you wanna get into the nitty-gritty, but if you're not a trail blazer, you can follow in the steps of satisfied customers. Coil-overs can provide excellent ride quality on the highway, excellent cornering etc... But you should do your research on the damping and adjustments offered on various setups. Picking the springs is pretty easy, but each coilover has pretty unique adjustment qualities when it comes to damping.

And i 100% agree with some above comments. In addition to coilovers, you'll seriously want some swaybars (and probably endlinks) as those alone can really increase the cornering potential and feel of the STI.

Not to open a whole new can of worms, but im also convinced that the OEM bushings are ALL too soft and a total bushing upgrade would lead to a world of difference in cornering and instantaneous response.
 

Batmobile_Engage

Squirrel Meat Aficionado.
Staff member
What size wheel and tire are you running? At one time I had 18x8 225/40-18's on there and now I'm
running a 17x8 235/45-17. The extra rubber seems to suppress a lot of bump noise and vibration even
more than I expected.

Also, I like the idea someone posted earlier about running stock struts with lowering springs. I had Apexi
coilovers on the car when I bought it. They were getting to be in bad shape, didn't handle like I expected
and were just plain rough on anything but perfect roads. Since I didn't have the stock struts around, I
replaced the coilovers with a set of Tokico D-spec (6-way adjustable on rebound-damping) gas shocks
and RCE Yellow (street and track) lowering springs -25mm front -20mm rear. I also have whiteline adjustable
sway bars, ends links, bushings, etc. etc. installed.

For an even smoother ride with roughly the same performance, I'd use this setup with the RCE Black
(regular guy) lowering springs.

I really like the way the car handles AND feels now. I like being able to adjust the damping rebound which
allows me to change the car's attitude in turns, for example, tighten up the rear end more on a short auto-x
course to induce more oversteer.

The shocks have to be set evenly from side to side otherwise stability during accel/decel is horrible. It's very
easy to tweak the shocks right in your driveway though so don't worry. FAR EASIER than adjusting coilovers.
 

Grinder34

Track Monkey
It's very easy to tweak the shocks right in your driveway though so don't worry. FAR EASIER than adjusting coilovers.

How hard were your Apex'i coilovers to adjust? For me its just a knob on top and a knob on bottom. Are your Tokico's even easier?

But right-on :tup: to everything you said.
 

Batmobile_Engage

Squirrel Meat Aficionado.
Staff member
The Apexi's had two large collars so to speak over threading on the shock body. One adjusts
ride height and the other damping. You need a large spanner wrench to turn them. After a
while, the collars seize and the threading gets ruined by corrosion and pitting, especially if you
live in the snow belt and deal with salted roads. I could NOT turn those collars on 2 of 4 coilovers
at one point. I wrapped the area in a penetrating oil soaked rag for days, used a cheater bar on
the spanner wrench....broke the spanner wrench. Heated the area with a freaking torch, cheater
bar, new spanner wrench....no dice. What a headache. So I threw those in the trash.

The Tokico's have an allen wrench hole on top to adjust. You can get a small tool for your key chain
to adjust them without an allen wrench. TiC sells extensions for the rear shocks that pass between the
rear seat so you can adjust them with your fingers. These are okay but personally, I have my rear seat
bolted in at the bottom only and the top corners are somewhat loose so I can fit my hand and an allen
wrench in there. I can tell more easily how many turns I've adjusted them to. They come with a pamphlet
explaining how to tweak them.
 

Spamby

Meat Product Toy
Batmobile-
I am not quite sure about running stock struts with drop springs. It's a cheap way to do it but potentially the springs and struts may not be properly matched causing for oddities in the ride. Although, I hear RCE springs are supposed to be matched to the stock strut.

I think Feal does revalves on stock struts. That might be an option for getting a properly valved strut/spring combo on the cheap.

Septic-
I have heard some good things about Megan and some really bad things. I passed them up because they seem to be very hit and misson their quality.

"Some more information- My car will not have any track time it is strictly a DD/spirited driving, I will be happy with 300-350 hp (for a little bit) but handling is my top priority right now. My plan as of now it pp stock exhaust manifolds, crossover pipe and up pipe. I'm going full bore on the handling side of things though I just want to make sure not to fuck it up the first time."


Since your car is not going to see the track, my advice is to not get so caught up on all of the 11ty billion adjustable thingys and focus more on quality at your price point.
I regard this to be the single biggest and most important upgrade (aside from turbo/tune) that you are going to make to your car. Research, research, research and then stop and research again.
Save your pennies and get something of good quality and longevity.
 

Batmobile_Engage

Squirrel Meat Aficionado.
Staff member
Maybe I should have clarified that. If I was going to run stock sti struts with springs, they'd have very little to no drop.
The Tokico's I have are sized for a spring like the RCE springs I'm running. I bought them because they are good quality
and matched my setup. Not because they were super adjustable. That's just an added bonus. If I wanted all kinds
of crazy adjustments, I would have gone with another coilover and probably not be as happy as I am right now.
 
Thanks for all the great input. Research, research, research. For less expensive route I have found these http://www.rallysportdirect.com/Tein-GSS60-1USS2-Street-Basis-Coilovers just dont like the fact that it they are 10kg springs on all 4. Then there are these for a little more http://www.rallysportdirect.com/Apexi-N1-EXV-Coilover-Kit-Subaru-WRX-2002-2007-STI-2004. I like these due to having 10kg front and 6kg rear (this makes a little more sense to me), I can change ride high with out changing the stroke of the piston and they have some adjust ability.

Does anyone know the spring rate for stock?

I found the bushing thread here on IGOTASTi and I will be using the standard set forth by that guide for bushings http://www.igotasti.com/vBforum/showthread.php?299-Bushings-rubber-vs-polyurethane It just makes so much sense to me

I would like some input - let me hear what you got to say
 
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