Bilstein conversion

[teK--]

OK I am planning stage 2 of my suspension mods (even though I'm still gathering the parts for Stage 1 which is yet to go in ).

After spending a long time reading almost every relevant thread imaginable on many forums, I have a few questions re my non-Bilstein spec 2.5i!

The plan is to fit Eibach Pro springs which are approx 25-30mm drop on both ends, matched with Bilstein B8 Sprint dampers. The B8 are a shortened body design especially suited for fitment of lowered springs (The B6 "Sport" aftermarket model and also the OEM Bilsteins which are fitted to the 3.0R-B are not intended for lowering. The latter are also known as the Bilstein "HD" in the USA).

I have read when fitting the 3.0R-B/HD dampers into cars that are not factory-equipped with Bilsteins, will require B-spec front strut mounts (the plate at the top of the strut assembly with the studs that are visible in your engine bay).

Q: Will I still need new strut tops if I am fitting the B8 Sprints??? Are there any other parts I may need?

Also has anyone else done the same or similar conversion and can offer any tips?

Other parts that will also be going in as part of Stage 2:
- AVO heavy duty swaybar endlinks on front and rear
- Whiteline roll centre adjuster

Parts that will already have been installed as part of Stage 1:
- Whiteline 20mm adjustable rear swaybar
- AVO heavy duty rear swaybar mount brackets
- Whiteline Anti-lift/Caster adjust kit
- Whiteline front control arm front bushes

As for coilovers again I have read this topic to death and as I am after a long term, durable solution I opted not to fit Coilovers. A quality set to last as long as I want without needing rebuilding (100,000Kms+) either does not exist or is vastly cost prohibitive and would then be overkill for my intended use of the car. (Spirited daily driver with the very occasional track stint).

[julzzychan]

um...very hard to mod for non Bs. maybe u ask the 2.5i NA in the forums? any luck with that?

[Gunna]

Hey Tek,

I thought that all the main reputable spring makers like H&R, Tein and Eibach all tested and designed their springs for the OEM Subaru Bilstein shocks.

Thats why its so hard to find good springs to fit standard Subaru shocks.

Whats your sourse and cost for the B6 Billies? I dont see Subaru Liberty on the Bilstein shocks after market product list.

As someone who also has a non-bilstein equiped Lib I will be interested to hear how your strut/spring upgrade goes.

Keep us posted.

[teK--]

Hi Gunna,

The spring makers might intend for their spring rates to closely match the damping rates that can be adjusted into the OEM dampers, but the fact is that as soon as you lower the OEM dampers they become pre-loaded and are under stress before any suspension compression occurs. The easiest way to look at this is that their duty cycle becomes much higher and so the wear rate is higher.

As for fitment of lower and/or firmer springs onto the stock non-Billie dampers, you can do this as long as your mileage isn't over about 50,000Kms or so, which is when they are reasonably worn even on standard springs. The reason is that the new springs will accelerate the wear rate much much faster. Furthermore, before the dampers die you will have to be content with a ride that is not properly dampened and will be similar to a pogo stick or the car feeling floaty during long sweeping corners or climbs/decents. The dampers just are not up to the task of controlling the sports springs.

Out of the brands you referred to I believe TEIN specify the hardest spring rates as well. H&R and Eibach Pro series are more a touring type of sports spring rather than something intended more for the track or perfect roads.

I am sourcing the B8 Sprints (Short body. The B6 Sport are long body and for standard height springs) for $1400.00 set of front/rear through a mate who has access to wholesale pricing. Based on my research so far, I will also need to buy B-spec (same as JDM spec) front strut tops which are about $140.00 for the pair on Japanparts.com. I hope there are no other surprises especially if they are not realised until the day I have to put everything together!

I have also read that fitment of the new strut tops will raise the front suspension approx 5mm which increases the height difference between front and rear. What some of the LegacyGT guys have done is purchase aftermarket spacers made out of Polyethylene sheet plastic, which fit onto the top of the rear strut assembly combined with longer studs. This of course raises the back by 5mm to neutralise the height balance of the car.

Ideally this is what I would do as I am more interested in maintaining the proper height balance and caster angles of the car, moreso than having a car that looks slammed and is equal height front/rear. This is just leading to more and more and more costs that are blowing my budget out!

Worse case scenario I may have to resort to fitting KONI Yellow dampers instead, which will avoid the need to get new strut tops, and also cause no change to the front/rear height balance of the car. Even though in my previous car I have had KONI inserts fitted and they were fantastic for 6 years which is when I sold the car, I just really don't want to have to go the cut and shut method on my Liberty and would much rather the whole new Strut assembly that the Billies provide (more rigid).

Long story short I will update this thread as my project progresses