FIGS

iTrader: (11)

I resolved the ride issues with BC racing coilovers. 14K/10K spring rates and 30-way adjustable damping. Install is simple, took me 4 hours taking pics etc.
I sell then for MAP which is $1100 shipped in the US.

The main issue is that the stock suspension compensates for soft springs with overdamping. This means the fluid is overrestricted from flowing through the valving and why small bumps become a big problem. High end coilsovers decouple the damping paths between high freq and low freq as well as compression and rebound. The high freq path should be a quick dump path that allows instantanious damping. The low freq damping should be progressive to account for force changes at different speeds.

So far 10K miles on the BC's and still loving them. Its really a radical transformation of the handling of the vehicle and worth every penny.

http://figsengineering.com/suspension.htm


Fig

Splat

iTrader: (3)

you paid to have coilovers installed

darkdream

I think he meant for the actual coilovers themselves with installation.

lobuxracer

iTrader: (2)

How did you arrive at those rates, and at what ride height is this rate best? Since roll couple typically increases as the ride height drops, stiffer springs are needed to counteract the increased roll couple's leverage. So, I'm wondering how you arrived at these rates...

I agree the high speed compression damping is way overcooked. The low speed works very well though, at least from my brief track time in two different Fs.

FIGS

iTrader: (11)

I took an educated guess based on the weight distribution of the vehicle and cross referenced it with several other vehicles with similar weight distributions then added a bit of margin for a stiffer front end. The front is lowered 1" and the rear about 5/8".

When I received the first set from BC with these spring rates I was pretty happy and decided that after 1000 miles of road testing, this should be a suitable application for this vehicle.

I looked at mostly larger sedans in the BC application group to leverage previous model testing. I knew that with a stiffer spring rate up front, the tendancy to dive in on a corner would be mitigated, one of my largest complains with the F on tight radius corners. In stock form it was almost a delay in the steering input from the time the body rolls to when the outer wheel actually digs in and kicks around the corner. Now I have flickable steering and a well planted rear end that is predicatable. 4 wheel drifting is flat and controlled and the car is poised for acceleration out of exit. Like I said, its a drastic change in personality, yet at low speed it seems better behaved on small road cracks and manhole covers. The suspension does not conduct into the chassis like it did previously and every crack may still be felt, but to the degree expected.

With these spring rates there is good damping range and at 25 clicks out, things are down right soft. I wanted to find a spring rate the made the damping range usable...after all you dont want to sit at 1 click out...similarly you also do not want to be at 29 clicks out. There is nice critical mass in the center from 5 clicks to 25, the suspension acts accordingly without getting too tight or too sloppy.

Another reference point is that my wife has more opportunities to take a drink out of a water bottle without getting it on her lap

primecut

iTrader: (1)

I guess the ride is really harsh, but it all depends on what you are comparing it to. The F's ride is plush compared to my 350z, and the S2k probably rides like a go-cart in comparison, right? ha ha.

FMA08ISF

Reliability and fuel economy could be the reason why British Police Choose The Lexus IS-F - Web Exclusive

Humberside Police in north-east England have taken delivery of a Lexus IS-F in order to make life more difficult for those looking to travel to the region to commit crime.Specially trained officers spent 12 months evaluating a number of high performance vehicles. They are set to replace their current fleet of Subaru Impreza STI, which have proved highly successful in enabling the Roads Crime Section to target organized criminals in the area. Following a stringent evaluation process, the decision was taken to purchase the Lexus IS-F after the vehicle proved to be exceptionally capable of remaining stable in high-speed policing operations, despite carrying $50,000-worth of on-board computers and communications equipment.
Sergeant Mike Peck of the Humberside Police Roads Crime Section said: "The purchase of the vehicle wasn't an easy decision and involved research and advice from the force fleet manager, financial managers and a vehicle dynamics expert. The Lexus was tested during a 12-month period along with similar vehicles and proved itself to be ideally suited in providing a dynamic and safe high-performance chassis, along with an electronically stable platform for the computer equipment.
"In the past, this equipment has placed huge demands on vehicles but the Lexus IS-F easily met our requirements. The final product provides a formidable package and is undoubtedly one of the most advanced police vehicles in the world. In turn, this will enable our officers to deal with the criminals who use the roads for serious organized crime."
The Lexus IS-F has a performance tuned 5.0-litre V8 engine capable of reaching 62mph in 4.8 seconds and a top speed electronically limited to 168mph.
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