fly_s2k

iTrader: (1)

I am looking to get my LS460 lowered about 1.5" all around and am inquiring about coilovers, specifically BC racing. I've tried searching the issue, but I wasn't able to find an answer and the discussions revolved around guys using air bags.

My question is that the std spring rates that ship on those coilovers are like 12kgmm/8kgmm. Compared to what Tanabe lists for their lowering spring rates, that's a significant increase in stiffness. I want the ride to be close to OEM. Does anyone have direct feedback on this? Sounds like the coilovers would be very stiff even with the damper settings adjusted. This is the first time I'm looking to equip a non-sports car with coilovers, so the philosophy perplexes me a bit.

I know someone mentioned having BC swap the spring rates out for something closer to OEM rates, but I wonder how that would affect the performance of the shock and/or ride quality. I am NOT looking to make this car a canyon carver or track car, so I do not want the stiffness.

I am contemplating to just get the Tanabe lowering springs, but I worry about the reliability of the OEM shocks with the drop. Plus I'm not fond of the raked look from the front being dropped from than the rear if I could help it.

Devh

I do not have a set up with the LS but I have experience in setting up coilover systems as well as tuning and corner balancing.

I take it that you just want to lower for looks. Fortunately your goals of lowering the car 1.5 inches it would be conservative enough not to ruin the handling. I would go with lowering springs over coilovers for this kind of application because the spring rate for lowering springs tend to be on the soft side. The only drawback is the increased premature wear of the stock strut and the possibility of hitting the bump stops. This set up should last you at least 60k miles and the replacement struts are cheap.
Going with Coilvoers is a mixed bag because of the increase in the dampening force which you cannot dial out with cheaper coilovers like the BC. The adjustment **** is a joke and it will give you disproportionate dampening depending on where you tune it. These coilovers are technically non adjustable unless they are double adjustable like the high end variety.
Also BC quality is not the greatest for some other makes. What ever you do, stay with a twin tube design rather then a monotube for this kind of application.

Devh

I forgot one more thing that is important. When you lower the car then you will most certainly increase the camber. How will go about fixing this issue because you will probably run out of adjustment. I would do a search for camber adjustment bolts.

fly_s2k

iTrader: (1)

Yea, that's what I was afraid of too. I was hoping that my skepticism wouldn't be validated. Thanks for the feedback.

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Devh

It would be nice if TRD would make a replacement strut as they do for some of their other vehicles. I would imagine they would go with a one inch drop however the spring and dampening would be tested on a shock dyno . I bet it would give you a BMW ride without a sacrifice in comfort. BC and the cheaper Taiwan/China coilovers are so generic they actually just weld on the mounting hardware to existing designs. There is no real world application and can be down right dangerous with a poor set up. The only other manufacture I would trust for a street setup is TEIN because they actually test their products on the application and tune for them.

fly_s2k

iTrader: (1)

I was hoping that Koni would mfg some shocks for this application as well. I've ran their street and race shocks with great results on the track. But seems as if good options are extremely limited.

kene

iTrader: (2)

Based on my experience with BC racing, when I ordered my coilovers for my gs300 I ordered 14kg/mm-front and 12kg/mm-rear set at full stiff all around (stock spring settings are 10kg/mm-front, and 8kg/mm-rear on the dampers BC provides). The ride was great for handling on turns and such, but with every dip in the road there was a strong "jacking down" of the car at full stiff settings (strong rebound settings). So much so that it literally would began to give me a sharp pain in my lower back (my fault for setting full stiff). I did not mind as it became super easy to swing the tail end of the car around in a very controlled manner.

But it seemed that this level of handling on the street only lasted for about 3 weeks to a month, then the firmness of the dampers gradually became softer and softer(without changing from full stiff) until my car began to get loose on the bumps....its as if something (internal seals, or break down of oil?) wasn't holding up the pressure in the rebound portion of the damper stroke. And the rebound pressure was not as strong as before.

On cold nights the damper would get firmer at the start of the run, but after being ran hard would start to loosen up. Now that I think about it, it may have been the viscosity of the oil in cold vs hot.

Either way I attribute 2 things to my desire for more with the BC racing coilovers.

1) Whether I ordered a 12kg/mm coilover for the rear or the stock 8kg/mm coilover for the rear. The dampers I received in bioth cases were valved the same, but with different spring rates. Which in the case of suspension, one specific damper settings cannot work optimally with every spring rate. Hence why I want to revalve my spare dampers to match my preferred spring rate.

This may relate to you because changing to softer springs may provide an overdamped or critically damped(or even worse) system. If you are going to go with an oem spring rate, you may want to keep a shock damper revalve as an option if things don't work out.


2) Do not use the 2 highest clicks on the stiff settings. I learned about this from BC racing of florida(via phone) after the fact. They recommend for longevity of your coilovers to not use the 2 highest clicks. So in reality, for longevity there are 30 levels of adjustment, not 32.

This relates to you in the fact that if you get super soft springs, there is a possibility you may want to compensate for the softness and make them stiffer. Just know that the top 2 clicks you may want to stay away from.

BC racing is an ok option and value for what you get. Because I did not stick with the original BC stock settings, I am now having to make up for it through doing the custom work and research myself.

If I had to do it again, I would have kept the lowering springs that came with car, and got some bilstein HD's... period. Although the benefit of this is I am forced to dive deep into suspension calculations and theory with the goal of re-making my BC's something in close proximity with ohlins or Penske. But this takes a lot of time and research, which can be better spent elsewhere. Truth be told I am still on the border line about shelving BC and buying bilstein's and lowering springs.


Hope this helps.

Devh

Koni makes a good reliable strut, it's too bad that they only make them for performance applications. The company I think that makes a great street application is Bilstein. Many of the aftermarket factory branded options like TRD will use Bilstein. I have test driven a Miata with the factory option on their touring package and it was balanced.

is150

iTrader: (10)

Unfortunately there is not enough adjust-ability for the front with the coilovers offered for the LS460 . With my megan coilovers I have the front set as high as possible and still have 0 wheel gap ( winter mode, Still not an issue for me because I have Platinum Vip cup kit so I can air up an additional 3 inches). There is enough adjust-ability with the rear for a 1.5 inch drop but not the front. I am going to try swapping swift 9 inch springs in next spring to see if I can get a little bit more height out of the front.
If you do decide to go with coilovers you will lose some of the ride quality but its not anything Id consider harsh. I still have some of the "float" that the stock suspension offers. I found the biggest difference to ride quality was when I put my 22 inch wheels on. Ride became significantly stiffer and louder.

fly_s2k

iTrader: (1)

Thanks for your input. So with the megans, even at the tallest setting youre at zero wheel gap in the front? Was this with your 22" wheels? Would you estimate how much of a drop that translates to? Although subjective, would you be able to quantify how much stiffer the ride was, ie. 50% stiffer?

is150

iTrader: (10)

With my stock 18's and tires the fender are in line with the top of the tire. My 22's actually are a slightly smaller diameter so there was actually more wheel gap but it didn't look like it due to the 22's having a more aggressive offset and push the wheels out.
Coilovers with stock wheels is about 15-25% more stiff (shocks set at 16). With the 22's on 40-50% stiffer (shocks set at 16). Obviously this is all relative. I was worried that the coilovers would ruin the stock ride, but to me they didn't.
I have pictures on instagram, username is LS_150.

is150

iTrader: (10)

Check out post #14 of this thread
https://www.clublexus.com/forums/ls4...them-pics.html