BC Racing Coilover Review
For those interested in suspension upgrades there are numerous options from springs to coilovers for the G37. For those of you who have driven the G37 the suspension is a bit tight as you can feel every bump and crack. In most cases you are looking for a more stanced look with better handling, but you don't want it to be a back breaker and so stiff you can't drive the car as a daily driver. I'm sure you have seen these cars, they are the ones that go down the road and bounce over everything.
|Before going forward I'll take this time to discuss spring rates. A spring’s Spring Rate is the amount of weight required to deflect a spring one inch. The lower the Spring Rate, the softer the spring. The softer the spring, the smoother the ride. As a reference, the Infiniti G37 sport coupe has the following spring rates: 8,500kg front, 8,200kg rear.
When I first purchased the coupe in 2008 there were no dedicated aftermarket products for it, thus, some of us tried using G35 coupe parts. In my case I installed a set of Tein H-tech springs. These springs have a spring rate of 5,800kg front and 4,700kg rear. When compared to the factory spring rates these were much softer and resulted in an ultra-smooth ride. It sucked up bumps and was really comfortable. With that comfort there was a down side: ride height. The overall drop was in the 2.5" range which is really aggressive considering there were no aftermarket parts available to fix the huge alignment issue that came with them. The suspension was also so soft I would scrape
For reference I've had the BC coilovers on my Infiniti G37 coupe since 2011 so I have quite a bit of seat time with them. The kit comes with everything you need except for detailed instructions, which was the first annoyance I've had with the product. From a quality perspective I can't really complain as I've not had any major issues with them from a materials perspective. From a design perspective you can't adjust rear damping without raising the vehicle. The prior "G35" style BC coilover, with the adjustment knob on the top, allowed the use of extenders which allowed you to mount the 30-way adjustment knobs in the trunk. The version I received had the adjustment knob on the side. I understand this change was due to people not wanting to drill a hole to run the extenders. In my opinion there should have been the option. Regardless, moving on....To allow for alignment adjustments Eibach front and rear camber kits were installed.
The BC Coilovers for the G37 sport coupe come with spring rates of 12,000kg front and 10,000kg rear; thus, they are much higher than the factory rates. This is REALLY evident on the road. For cornering and curvy roads the car handles very well, but with some rear hopping in case of rough curves. This is offset by a wide margin due to the harshness of daily driving. Every bump, rut, and hole is felt through the car. Long trips equate to a sore back or posterior. NOT what I was looking for. While the front was harsh most of the issues seemed to come from the rear suspension.
After a year of dealing with the harsh ride I went ahead and purchased a set of 10,000kg front and 8,000kg rear springs and immediately swapped the rears and went through the enjoyment of trying to readjust the ride height. Being softer the vehicle settled too low, as expected. What I ran into is when adjusting for height it would put too much load on the springs which made the vehicle really stiff again. It was the oddest thing and I've had others validate as they ran into the same thing. Thus, I eventually set the ride height slightly lower than I wanted in the rear and it's been that way for the last few years. With the rear 8,000kg springs the ride is much better but it's still harsh....just not harsh enough for me to pay for another suspension. It does much better on curvy roads as the softer springs allows more movement. You can still feel bumps and at times they can be painful, I've just learned to live with it.
To note: I've never had any issues with the struts in my vehicle "clacking" after installation. I have been in other G37's with BC coilovers and have heard the noise and it's a bit annoying. Unfortunately, for those individuals, it seemed the only solution was for them to replace it with something else. I'm glad I've not had to deal with that decision at least.
Conclusion: Overall, if your main goal is to have an adjustable suspension for a vehicle which is primarily a weekend warrior or a track car then the BC coilovers would work fine. If you appreciate an overly stiff ride that is difficult to adjust then they will work fine for you as well. Hindsight being 20/20 I personally would have gone with something else.
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