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      11-06-2018, 03:10 PM   #1
dre99gsx
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BC Racing BR track setup review

Mini review on my 2 year old BR coilovers.

Installed them 2 years ago, and have put about 8000 miles on them, and:

- 73 HPDE sessions (13 events), mostly intermediate/advanced groups.
- roughly 25 hours of track time

I'm running stiffer springs than the standard (9k (504lb) front, 12k (672lb) rear. When purchasing these, BC mentioned 12k is the maximum I should go without needing valving change on the rears. Also, keep in mind I have about 100lb more in front due to the 2J engine. I also run these at almost full stiff setting front and back (29clicks out of 31-ish).

I run wide sticky street R-comps, including stiffer 27mm front bar, and have consistently improved my lap times almost every session as I learn and progress.

The adjustable camber plates make camber adjustments super easy. Installation super easy. I do have to lift the rear end to reach the rear shock adjustment just inside the wheel well gap. No biggie...

From all the reviews I read, these were cheapo Chinese units which should "never see track time". No one really provided anything to back up that claim, so I bit the bullet and tried them out.

I've run some competitive lap times with this platform and tire selection, at the local tracks, and spent considerable amount of time fine tuning the shock adjustments to end up with a neutral feeling car. I really have awesome feeling of control throughout a corner with these units. These also handle rumple strips/curbing well without feeling twitchy or jumpy.

They have not leaked, nor fallen apart, nor made any noise. I'm surprised myself. Fact, I even called BC to see if they had anything higher end for the nonM Z4 (which they don't), and were also impressed, strangely.

How do they perform? This is mostly subjective, but I do feel as if the suspension reacts slightly slowly during quick transitions. On corner turn-in while trailbraking, I'll feel the car roll slightly for a fraction of a second, before feeling it "catch", almost as if the shocks need a bit more compression.

I don't know how much better a GC, JRZ or Ohlins will feel, or if it will provide me anymore confidence or better lap times. I almost wonder if gonig to $500 units will feel just as good. What do I know. But, for the money and thus far reliability, I have to say these units have performed well beyond my expectations.

I do wish there were competitive drivers using these with data to back up their performance, but those are few and far between (seems like you only see them in drift series). Most competitors jump right for the top shelf units.

Interested to hear any other feedback on these units from those who track their Z4s!
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      11-07-2018, 03:10 AM   #2
Westersund
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I run these on my Z3 Coupe track car and I'm very happy with them so far, if I don't remember incorrectly I run 8 Kg spring all around. But my car is significantly lighter than yours. What's the reasoning behind so hard springs in the rear?
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      11-07-2018, 03:25 AM   #3
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If you feel you need more compression then it's time to move onto something else

Seems like you have enough experience to take advantage of a high end coilover. Many people buy an expensive coilover and have zero knowledge why it's good.

The biggest difference I've felt from kw to Jrz was how one click in compression significantly changes the behavior of the car. Therefore i had unlimited adjustability to make the car behave like I want it to, while with kw it takes about 3-4 clicks to rly feel anything imo.
Also kw kicks over bumps. Jrz absorves it. So more contact to the track -> more grip -> more confidence -> faster laptimes.
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      11-07-2018, 07:20 AM   #4
dre99gsx
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Harder springs in the back is only because the springs sit further in between the control arm and chassis, they aren't one piece coilover. The effective rate is essentially the same as the front by having 100lb difference.

Thanks for the input AriuSen - I am considering moving up to JRZ and "trying it".
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