boggissimo

Can you post up the second half of those geometry settings (track) please?

uxon

Thanks for the info
41N/mm is about 234lb/in and 39N/mm is about 223lb/in. Compared to stock 224/195 lb/in, it's about 4% front and 14% higher spring rates. But if these spring are 3 way progressive, the are numbers that you provided an average of all progressiveness levels? Or are they for the medium level?

Being honest my thinking was that it must be similar situation like with P1 - so I thought that prodrive springs are a bit softer than stock ones. If prodrive springs are a bit stiffer, it means that stock suspension is closer to what you described:

2pot

iTrader: (3)

Those are the max rates.
The WA/A2 are 43N/mm 39N/mm, but linear in their operational range.

uxon

But shouldn't softer springs be better if they 'maximise the mechanical grip'? And the softest from all mentioned are the stock ones.
What if I put a bit softer springs instead of the stock ones (together with softer front bumpstops)?

At the moment I think that I will decide to change the front bumpstops for the prodrive version. Now, the main question is which springs to chose (from the ones that I have available):
- Stock sti v8 (so just regrease struts and put in front prodrive bumpstops);
- Prodrive red (s03 ones), which according to what you said are a bit stiffer;
- Eibach pro kit, which are a bit softer (about 20%F/15%R according to the info that can be found online). Where I live, these springs are the most popular mod to sti suspension, but they are getting different reviews. Some say the ride is more refined on them and the others say the opposite, that they use it only for autocross and they are ok only for flat surfaces.

What do you think, which of these 3 options will give me the best combo with stock sti struts, in a car that rides 90% of time on bumpy, pottholed B-roads? As I mentioned before, I don't want to lose too much of my suspension's performance (i.e. go back to stock wrx setup), I just need a bit of refinement.

Avalyn, thanks for the photos and the measurements
I am really curious if you will be satisfied with your new setup.

2pot

iTrader: (3)

Investigate 'flat-ride'. That's why my front springing is slightly stiffer than the S05 Prodrive.


S05/d5/001 are the 05-07 prodrive sti springs

S03 are a softer, lower, prodrive set-up

uxon

Very interesting yt channel! For sure I will watch some more videos of them. But in that video, the guy says you should have higher frequency in the rear thatn in the front. And you are saying that you prefer stiffer springs in the front. Isn't it in the opposition to his advices?

At the moment my choice is limited to mentioned springs: stock, red prodrive s03s or eibach pro kit. Which would be the best choice according to my needs?

2pot

iTrader: (3)

A 43N/mm 39N/mm spring rate combination are a higher rear ride frequency.

Ride frequency calculation depends on wheelbase, weight distribution, motion ratio etc.

Again, S03 are too low and too soft. S05 are altogether different.

I'd stay with stock springs, use a 20mm rear bar and change the front bump stops.

uxon

You said that Prodrive's (S05) are 41/39 and WA/A2 are 43/39. I assume that first number is about front springs, so front WA/02 are about 5% stiffer than front S05s. Doesn't it mean that front frequency also be higher on WA/A2?

About S03s - so do you think that they are not worth trying, and just better stay with stock springs?

2pot

iTrader: (3)

Yes - flat-ride therefore is biased to a higher speed; everything else being equal.

If you want to run a soft spring, on a bumpy road, you'll need more travel - The S03 is low and soft: no use on a bumpy road.

s05 - progressive - not 41/39 at smooth road ride height
wa/a2 - linear

uxon

What do you think about KW V1 and Eibach Pro Street S coilovers? How do they compare to stock STI suspension in terms of ride quality? Generally opinions about coilovers (at least cheap ones like KW V1, Eibachs, BC BR, Tein SS) are divided. Some say they are much harsher than stock and others say the opposite - that they are firm. KW and Eibach seem to gain best reviews in that price range and I could buy a set of them second hand. Will they do a better job than regreased stockers with changed front bumpers in a daily driver?

plenty

iTrader: (13)

I have run Eibach Pro Street S and KYB dampers/Prodrive springs back to back on the same GDB. The KYB/Prodrive combo was much better for the road.

2pot

iTrader: (3)

uxon - what are your wheel centre to metal arch measurements, front and rear? And how much fuel in the tank when you take the measurements?

uxon

Hey plenty, you have written that you tried red prodrive springs some time ago. Do you rememebr if they were S03 or S05 ones? How do they compare to your current rb320 springs?

I will measure it but it seems that I have to think about my suspension sooner than I thought. My front right spring is a bit broken - nearly one (the lowest) full coil has dropped out. So at the moment in the front, left side is half an inch higher than the right side.
Do you think that I could try to cut one coil from the other side and the springs would work fine? Or are they trash now?
What is more interesting, I see that my rear is also not even left and right. In the rear also left side is a bit higher than the right side. The difference between sides is smaller than in front (I would say 15mm in the front and 10 mm in the rear). I checked both rear springs and when the car is lifted they look the same (the number of coils is equal). Is it possible that the source of the difference in the rear is the front right broken spring?

plenty

iTrader: (13)

S05. I've not tried the S03. The S05 red springs are similar in rate to the RB320 items, but the RB320 front is shorter than the S05 to create the front rake which an important part of the RB320 setup. The diameter of the rear RB320 springs is slightly larger than the S05 rears, although they are basically interchangeable.

2pot

iTrader: (3)

Track setting (Rear anti roll bar in 1st hole, nearest the mounting bush on the bar)

Values are read: preferred

Front Camber -1°30’(Maximum negative on adjustment)

Front Toe-in (Total) 0°06’

Front Caster 3°00’ (Referential value)

Rear Camber -1°30’(Standard Subaru)

Rear Toe-in (Total) 0°06’

Thrust angle 0°00’

Markyscoob

The Standard car is a mess. IMHO. The Bump stops are the main problem, as stated, but the damping is really ****, as it needs to cater for the two extremes.

Let's say you are cornering, well in this instance, your inner shocks are going to be off the bump stops and massively over damped, the outers are on the bump stops, guaranteed, and either correctly or most likely under damped.

I went with a Whiteline ARB to start with, then an ALK, then Coil Overs to try and get rid of the undesirable traits of my 06 STi.

Had a good chat to Peter Cambridge, the man really knows his stuff, before I ordered my BC Racing ER series coils in long travel plush high speed damping with 6kg/5kg springs.

I now run 5kg/4kg and may well go for softer springs again when I get them off shortly to go for their 5 year rebuild at Apex. £50 a corner is pretty good going, plus any bits that need changing due corrosion.

Linksfahrer

Found myself reading this story in sympathy For anyone un-satisfied with WRX 01-05 Suspension , I cannot imagine anyone not being so by now on tired out OEM,
So my recomendation would be a set of BC coilovers and setup to Prodrive Tarmac Setting - drop 30mm ride height at Sub-4-you. They literally transformed the cars handling for me, I drive this now very fast on German roads & ring. never felt it bumpy or harsh. Job done for under 1k €

TECHNOPUG

iTrader: (1)

Lifted from my project thread:

Excel Gs with Prodrive (PCA) Blues has been the best of the 3 set-ups I've tried IMO.

The problem with that setup though is that the KYBs are perfectly matched to the springs when they are NEW. As they age, they soften and their performance deteriorates. Noticeable after 30k, shot by 40k.

So not wanting to keep replacing them (although a lot would depend upon mileage) I replaced the KYBs on my Bug with Koni Inserts. Reason being is that they are adjustable, so I can keep tightening them up as they age.

That's the theory. The reality is though that new, on the softest setting, they are too stiff (for my liking) for the springs. So like a fine wine they will get better with age but I don't know how long that will take....they may be better suited to the higher rate "red" springs.

What attracted me to the Meisters was that you can set them softer than stock, so they have a wide range of adjustment - handy with a little one on the way.

However, if you set them in comfort mode, whilst the compression is great, the rebound is too soft. So the springs oscillate and you get an unpleasant wave effect. Playing about with the settings at the moment, turning stiffness one notch at time for a few days whilst driving on familiar roads. Haven't found the sweet spot yet. My concern is that in order to get the rebound just right, it may result in the compression causing too stiff a ride (rebound & compression adjusted jointly).

The other thing that has crossed my mind whilst driving today, is that it may be the springs which are the weak link. I believe that they are 6kg front/5kg rear? I don't know what the spring rates are on the Blues but I'm sure that is the key to their great comfort/performance ratio. I might ask Peter Cambridge but I'm not sure if he'll tell me to be honest.

Markyscoob

My ER set had separate compression and rebound. However, the Factory said they were uneconomic to repair, as the design doesn't lend itself to dismantling with the fixed pipe union going through the lower hub mounting part. So, the UK importer, bless him, did me a cracking deal on replacement.

Numpty that I am, I am now awaiting delivery of a set of BC Racing ZR series dampers. +40mm with their minimum (for warranty) spring of 10/8kg fitted.

So, inverted, remote hose to a gas bottle, separate high and low speed compression damping and, of course, rebound too.

These will live a cosseted life under neoprene covers to keep clean.As to your theory of aging Technopug, I can say the Dash 8 Q400s I used to fly worked like that. A set of new or reconditioned undercarriage legs (10,000hrs) were really difficult to land smoothly on, but one with 8,000hrs was like a magic carpet in comparison!

Currently, the brand new Boeing gear is a lot smoother than old ones.....


I'll have to experiment with the coil overs though. The thing is, the complexity at the top end means I'm more likely to remove the bottoms to change springs under the car.

10/8 is way too stiff for a road car. I'll start with the 6/5 and may try 8/6 too. With the weather, I might not get too much chance till next summer..

2pot

iTrader: (3)

Does the zr damping curve cover 6/5?
Weren't you were contemplating going less than 5/4?

Markyscoob

No. Bear in mind these are sold as for Track use... BC wouldn't put less than 10/8 in for warranty (what there is) to be valid. Their inverted units all carry track use and short warranty, as they are far less weatherproof. I stripped them on arrival, put more grease in and around and then used Neoprene boots and copious amounts of ACF-50 on the bottoms. I'm impressed with the quality, and they even have a boss to refit the ABS sensor bracket- unlike the old ones where it was missing.

The Damping curve is an interesting topic really. With the rebound having 30 clicks from rock hard to very loose, and 15 clicks of low speed and 12 clicks of high speed compression, you'd think it's quite tunable.

Having said that, the factory setting is 15 out on Rebound, and full out on all compression settings. I may find they are too rigid like that but you never know.

The car is not a daily driver anyway. I'm starting with 6/5 and then will go to 8/6 when the winter tyres come off. The 5/4 set were longer 2 1/2" jobs rather than BC springs.

I've fitted one, loosely, so it'll be a couple of weeks before the car touches back down from it's axle stands....

uxon

I have bought a set of second hand WR1 takeoffs which seem to be exactly a setup that you reccomended me (sti upside down struts with front prodrive bump stops and red S05 prodrive springs). The whole set has a little of rust here and there but it cost me less than a price for new springs.
Yesterday I unmounted springs from struts, it was real pain in *** on front struts to compress springs enough. After that checked by hand how do shocks behave. They all seem to damp similarly when pressing and depressing them, but I noticed one thing. After fully compressing them and letting them go, they start decompressing fastly (hard to notice difference in speed between each of them), but when they reach 1/2 or 2/3 from max bump, two of the shocks (one front and one rear) start rebounding much slower than another damper from thei pair. (like their internal gas spring is a bit weaker in one of the shocks from a pair)
I wonder if it's ok for used struts to have such difference, or is it something that is eliminating them for road use?

Markyscoob

Sounds like one of them is past it's best. But that's what happens with second hand stuff.

If I were you, I'd get the STI ones off, strip the lot and look for matched pair of dampers side to side, be it the STI ones or WR1. Then fit the shorter Bump stops and springs and rebuild with copious amounts of grease.

If you are feeling particularly flush, you could get the springs and lowers powder coated for a reasonable sum. I've a feeling any old crap wit hshorter front bump stops will feel better!

SmurfyBhoy

Just got these KYB for my Bug STI

Plan is to add PCA WR1 springs

New top mounts then fit,

I see the internal bump stops come with springs too

These wont be compatible with the KYB tho will they ?

Just to add Comfort wise even the knocking stock setup if far better than the BC coils on my weekend toy,

If I get the Bug riding correctly those BC's will be in the bin

uxon

I don't know if I fully understood you (what you mean by 'get the STI ones off'? get another set of sti dampers?), but in general it was my plan to get these WR1 struts into pieces, sand blast and powder coat springs and strut bodies, and fulfill them with fresh grease. I just wonder if the symptoms that I describe mean that dampers are near end of their life (so no point in servicing them) or is it normal for any used damper (let's say in 1/3 of their life or so)?
2pot, you seem to have most experience and knowledge about suspensions, what do you think?

2pot

iTrader: (3)

The bump stops, with the pca springs, must be fitted. They replace the front internal, 60mm, rock hard bump stops, with 50mm, soft-nose, bump stops.

2pot

iTrader: (3)

Don't use second hand dampers.
Bump stops are also wear items. Vehicles that use the bump stops, as part of the suspension rate, have a service frequency.
You must change the internal front bump stops, when using the S05/d5/001 springs.

plenty

iTrader: (13)

The WR1 was fitted with the softer S03 springs.

uxon

I have finally managed to disassemble them. After that it showed up that rear struts seem to work identically and front ones work nearly identically. So I plan to put them to my car.
I have some questions about the process, which I have put into a new thread: https://www.scoobynet.com/general-te...l#post11981686

uxon

I have done couple of miles on my refreshed prodrive suspension and general impressions are very good. They are very close to what I was looking for. The car runs very similiar to what it was on STI set, but without the drastic harshness. It's not a comfortable suspension, it feels sporty, rigid, just it's not that harsh. It's much firmer than wrx suspension and a tiny bit softer than stock sti suspension.
The only downside now is how the car feels on initial turn in. On stock sti suspension turn-in felt sharper, the car was immediately stopping on the outside bump stop - and I miss this feeling Now after turning the wheel firstly I feel body move for a fraction of a second and then I feel car turning.
I am wondering If putting larger arbs (22mm front and rear) could give me this feeling again without sacrifying comfort?