BC Racing DR Series Coilover Review
 

Hello everyone - I just stopped in today to my tuner to swap out my coilovers to the new DR Series coilover from BC to find out that I believe these were the first set in the country for our car. Figured since I use the car for plenty of daily driving, autocross, and some HPDE I could do a write-up just in case anyone else was considering them. I am coming from KW V3 coilovers, which were fantastic for the street but as my tires got bigger and stickier they were just not quite stiff enough.

I ended up doing some research and found BC's new DR series coilover, which is similar to the BR series but features a digressive dampening curve. The dampening on this shock is supposed to enhance handling for more technical tracks and therefore would be beneficial for something like autocross. Add to that the custom spring rates and shock valving that BC offers, pillowball top mounts, and rebuilding to your liking and it was a no brainer for me. I am also limited by the autocross class I compete in (A street prepared) - I need to maintain the OEM rear separate spring/shock setup. I ended up ordering the DR's with Swift Springs 18K front 14K rear.

Some pics from the initial unboxing/install at R/T Tuning in Montegomeryville, PA...

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Upon initial impression the shocks looked like they were quality pieces. There were no issues with installation, and I also had purchased the rear extenders which were a nice addition for easy dampening adjustment (pics to come later). After the install I had an alignment and corner balance done. Alignment specs are Front: camber -2.8 toe 0 Rear: camber -1.8 toe 0.08

My biggest fear with driving my car nearly every day it's not snowing is that the ride would suffer dramatically with the extremely stiff springs. I drove home from R/T Tuning in PA with a sigh of relief as even on the PA Turnpike (which is an absolute NIGHTMARE for potholes/dips/bumps/etc) the ride wasn't nearly as bad as I thought. Over nasty bumps I of course felt the difference in stiffness some more, but I'm talking bumps/holes I should have probably avoided regardless of suspension! Hah I am very happy so far with the feel of the BC's and ease of adjustment. I have my first autocross event of the season tomorrow morning and will report back with how it felt on smoother pavement at Metlife Stadium parking lot. My next event is 2 weeks later at a bit rougher surface at Bader Field in Atlantic City. Can't wait to test them out!! :happydance:

Looks good man. I ran the some BC coil overs on my STI a few years back and they were insanely rough, even on the softest setting so i'm glad to hear with the Swift springs they worked out.

Got to test out the coils a bit at North New Jersey SCCA Autocross on Saturday. WOW they corner super flat! I was afraid not having pushed them yet that the car was going to handle a bit funky until I got the dampening dialed in. Ended up going with 22/30 on the front coils and 15/30 on the rear. Got only a slight bit of understeer, but it was also a very cold day for the R888's. Here is a video from the event:



Also, after dialing back the dampening and driving a few days to work on them they honestly aren't all that uncomfortable for the much higher spring rates. I'm still very surprised and extremely happy with them... especially for the money.

Ran a super cold event in South Jersey this weekend. Dialed in the dampers to where I wanted them to be and they worked flawlessly. Didn't get too much under/oversteer and the car went where I wanted it to go. Felt a lot more responsive and was definitely able to pick up some speed on the slaloms which I think I had lost before due to the car rolling and the rear end sliding out a bit towards the end. Ended up 3rd overall raw time out of 80 drivers. The number one and two spots were a turbo s2k and supercharged miata on slicks that were brought in on trailers so I can't feel all too bad! Here is the video from the event...

Glad to see a review
 

Glad to see a review on these vs the kW as I am currently interested in either one. I will not go as firm as you and just stay stock spec 10k f / 8k r which already sounds very firm to me. I don't want a harsh track car as my dd so even those rates have me worried. I hear the KW are great for street and track so that makes me very tempted plus they can go all the way up to .6 drop which is good for me as I do not actually want to lower my z just want the ability to tweak damper rates. Still stuck between the BR, DR, and KW. The BC coil over are starting to sound like a very good product for the price and it's surprising to hear you switched from the KW to them (usually everyone wants the KW) only thing I'm not liking about the BC is according to them min drop is between 1-1.5 inches which is more than I want for street (been lowered on other cars and it just doesn't make sense for the area I live).

One thing I can not find anywhere after searching is what is the V3 spring rate? I have no way to compare them to the BC because KW has no published rate that I can find.

The KW spring rates are progressive so they don't publish them. I've asked and they refuse to even give a range.

Honestly I would go with the DR with maybe a 14/12k spring rates. The digressive damping and swift springs would lead to a stiff, but still rather forgiving ride. The 18/14k I went with doesn't feel nearly as bad as I thought it would. Hell... a lot of the competitive autocross Z guys went much higher than I went even (some 22-24k front). I'm very happy with them after the few weeks i've been driving and couple of events I've done.

Thanks for the review, I'm thinking of going with these with a 14k/12k spring rate, but now you have me considering going a little stiffer like what you have.


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Wow that sounds high
 

I think I'll just stick with their spec of 10k/8k as I want it to be 90-95% street ready and only 5-10% track.

What do you think the min drop you could get from them is?

Also having the kW and these do you feel the damping on these is just as good as kW and more important the compressions and rebounds are matched to each other well since they are not independently adjustable.

I honestly didn't adjust rebound on my KW. It was difficult to get to and I didn't know how the car would respond so I left it alone. Essentially I just treated them as a single adjustable coil then. The damping is pretty good though. For the spring rates/valving I'm running I thought it'd be a lot rougher, but it still soaks up smaller bumps/uneven pavement well. Big stuff is rougher, but thats only over things that I would tend to avoid regardless of which suspension I was on.

Cool thanks for the info. The kW are progressive and I was told the BC dr are progressive springs as well but the images look like a straight linear spring. Are they progressive or linear?

They are linear, which was another reason I went with them (especially with the Swift spring upgrade, which provides a more consistent spring rate as more and more load is put on the spring). Seen testing between springs that came with a set of coils (not BC but another brand) vs swift, and things were relatively consistent until you really put a lot of force on the spring. That's where the swift spring kept its consistent rate and the other spring did not.

Cool that is one of the other reasons I was looking at them is to stay with a linear spring for more predictable handling. Do you know if their stock springs that are rated at 10k / 8k are also made by swift or do you only get the swift springs with the upcharge? I may have to ask BC about that. Looking at the rates they may not be so bad vs Oem after all. From what I have found is the Oem are 7.5k front and 8.1k rear. So a bit firmer in the front but the same in the rear. Usually a firm rear spring can cause a pretty harsh ride as there is now weight in the back to keep it down, just have to think on if I want that much of a firmer rate in the front. Always read how harsh the Nismo is in testing and getting comments like its a track car etc and its rates are only 8.6f and 9.3r so makes me nervous.

They're not made by swift, its a separate upgrade. I believe $300? Worth it though to me. I'd say go a bit stiffer. Harshness with the Nismo may be due to more mismatched damping/spring rates than the stock 370Z has. It sounds crazy, but it's not always matched up well. That's why its nice to have custom valving for your spring rates you choose. Helps take away some of the rough ride if the spring/shock combo works well together.