tongpoh

Hi all,

I received my 2004 LS430 3 days ago, i plan to upgrade the suspension or springs for better cornering, i will used it for daily driving, i just want to reduce body roll when cornering, so lower springs and coilover, which one to go? I heard many LS430 owners using Tanabe NF210, anyone tried Swift sport springs before?

CircuitMS

iTrader: (51)

If you can get some, Swaybars would do more for quelling bodyroll and keeping a civil ride.

If you really want to up the handling and have height control then coilovers would be best over just springs.

ThaWatcha

i would fork out the extra cash for coilovers, you wont be disappointed

tochoks22

bc racing coilovers thats what i have I love them, may be a little harsh some times but i have them on a stiffer setting. Teins may be more comfortable but more expensive.

motohide

Well the long answer is that both standard coil spring/shock and coil over adjustable sets, change the spring rate and damping rate of the suspension. The stroke range also changes depending on the system.

A great handling car needs not be 'harsh' or 'uncomfortable' The reason many systems end up harsh is not only in the stiffness of the spring and shocks but also more attributable to the balance of stiffness of coils, damping rates on bound and rebound stroke, and stroke range.

The LS430 is fairly short stroked car even in OEM form, and wheel travel for the car is significantly shorter by design than most European cars. While reasons are many, most Japanese cars do have short stroke suspension designs due to the fact that Japanese and American roads normally are fairly level and even and paved with asphalt. Europe still has much of the roads paved in stones and boulders, necessitating the use of longer travel suspensions.

As such in OEM form there are still ample stroke on the LS430, for normal use. It is when we lower our cars, the stroke range significantly decreases as upper arms hit the end of stroke, fenders start to hit tires when turned, etc... It is primarily this issue, why most lowered LS430's ride harsh... It's not due to excessively high spring or dampers on most occasions, it is simply the suspension hitting bump stops on shocks or wheels lifting off pavement in high stroke situations. Body abruptly stops sinking to absorb the shock gently, and/or body lifts beyond the suspension range.

By use of well designed double tapped coil over, one can lower the car more effectively by making use of every millimeter of stroke, with absorber cartridge placed in complete stroke range of the car at a specific ride height, and also being able to select a damping rate and spring rate to correctly absorb much of the car's normal rang of motions in particular use.

By changing only the springs to a shorter one, one must stay pretty close to OEM setting because stroke of the shocks change as we alter the height of the car. This applies to non-double tapped coil-overs where only height can be adjusted and not the position of the shocks.

So when selecting the proper rates and design, decide on how you use your car, and how high your want to set your ride height. A well executed suspension is one that should ride comfortably for you and provide the desired stance and appearance, while not disturbing the handling of the car or improving it.

THere are limits on the LS430, but ill effects can be offset and prevented for the most part as long as you keep these factors in mind and carefully calculate and choose your suspension design.

Remember, its all done as a whole, and not part by part. Each spring rate goes with a particular need and mated to a specific specification of shocks and design.

motohide

here, the LS430 is equipped with Tanabe Sustec 5 Pro with custom spring rate selection of 10kg/mm front and 8kg/mm rear, the 3 way damper set at Medium Rear and Hard Front. The front suspension is spot-on for LA roads, the rear still lacking a bit of stroke. This rear suspension issue at this ride height is inevitable since the suspension design itself on the LS is very limited on stroke at this height, and it leaves very little upper stroke motions to suck up deep bumps with a load in the rear of the car. Something most Japanese sedans suffer simply due to rear suspension design of short arms and wheel well clearance, chosen in favor to provide passenger space and trunk/equipment/gas tank space. Not a design flaw mind you, the OEM height works fine!! LOL! Just that japan has smooth roads and very limited space to park cars and drive around narrow streets and tight garages.

The harder 12kg/mm-10kg/mm spring rate that comes standard with this coil-over system is perfect for Japanese roads where asphalt is glass smooth. I wanted a bit softer feel in the initial impact of the suspension on road while still effectively limiting the travel before bump stops of the very low ride height.

The stroke at this height is very limited and with 2 passengers in the back seat, the ride still does become a bit hard for abrupt bumps. However the car is very controlled and tolerable with comfort with 2 passengers. I like to have street-able suspension designs with usable ride height for Southern California streets.

This combination seems to me the best for saving the front lip spoiler from damage, while still not being too high for the body kit to lose the aggressive appearance. My choice of coil over setup was based on this height and designed around it with a mind that I do occasionally take it to the raceways as pace cars at times too. The ride height choice does force the rear stroke to be a bit short for total comfort on streets with a full load, but for the most part, it does very well as a comfortable commuter as well.

Again, it is a very carefully selected list of parts that all work together though to achieve it...

tongpoh

today i order a set of swift sport springs, will install it when it arrived. Any good absorber recommend than stock ?

motohide

Again, this is a matter of what the rate of the springs are, to match the appropriate shocks. I am assuming the Swift branded springs to be some small percentage stiffer than OEM springs with slightly reduced height setting, therefore a slightly stiffer dampers that is compatible with OEM mounting and possibly reduced stroke position is in order. However, most OEM based shocks do not change stroke position as it is assuming that the unit is to be mounted to a OEM spring set as replacement. I would therefore recommend slightly stiffer absorbers such as Bilstein Japan OEM replacement or Tokico which is basically a re-valved cartridge type absorber for OEM application with slightly higher gas charge rate. Bilstein and Koni do offer drasitically heavier rebound rates and does help on the handling side, but tendencies to bottom out are slightly more frequent as it takes longer for the car to rebound to full suspension length. Tokico should be very comparable to OEM with slightly stiffer compression side, adding to help control the slightly lower stance.

Since the modification by use of Swift is not drastic in both rates and height settings, it should not be a huge issue concerning ride and handling from original...with new fresh shocks of any OEM replacement variety, it should improve greatly if your old shocks were of high mileage units in need of replacement

tongpoh

about bilstein, which models suit for 2004 LS430?

motohide

For the LS430, Bilstein OEM style is only available in Japan, however comparable OEM replacements with characters similar to it and slightly more in-between the Bilstein and Tokoco are the KYB GR2 at about $650 per set of four.

They are mild gas charged shocks with about 5% increased dampening on compression and 10% on rebound, which should provide a good alternative for OEM based lowering springs of 10-20% increased stiffness and slightly reduced spring length (ride height), this generally no more than 1.5" drop to be usable. The piston stroke is still the OEM length so you cannot use springs that are drastically lower, but should suffice well for Swift road springs I would imagine.

Possibly the best offering in the USA, for such application. On the very good side of things, KYB is the OEM manufacturer for all Toyota cars, including most TRD applications so fitment should be very precise and reliable for the long run as well.

KYB Part# 341392 Front and 341393 Rear

(I am hoping Tokico will cater more to the aftermarket crowd for LS430 applications but at this time still a bit soft on both demand and interest it seems.)

tongpoh

how is kyb gr2 compare to oem sport absorber?

TJW98LS

iTrader: (1)

You're ride height is perfect for me. My LS430 is my daily, so I couldn't slam it like some people on the forums do.

motohide

GR2 Shock absorber is OEM replacement, so its very comparable to OEM.
By nature the GR2 is slightly stiffer to cover models of both sport package (Japan only) and regular LS430 rates of valving.
However, if your existing shocks are older than 25,000 miles, you will definitely feel it being stiffer, not because the GR2 is that much different, but the existing used OEM ones are old and lost some of its effectiveness.

tongpoh

Finally, today i replaced my stock springs with swift, lower not much but still very comfort, boat effect gone. If you dont want to install coilover, swift springs is a good choice for little upgrade, body roll is improve but not much, i think i will wait for a stiff aftermarket absorber.

motohide

Just a mental note for any suspension design:

The body roll amount is controlled by spring rates of the main coil and stabilizers, while body roll rate (speed) is controlled with dampers (shock absorbers) for the most part.

So the "amount" of body roll when in static state cornering is mainly dependent on the spring rates and stiffness of the stabilizers (or we call it in the USA, anti-sway bars or sway bars).

The speed at which the body roll occurs (how long it will take for the body to lean that far over to one side or another) is dependent on the shock absorbers.

Furthermore, the shock absorbers have two important characters, compression rate, and rebound rate. Compression rate is the effectiveness of the shocks in the same direction as the springs, and usually are gas charged (assisted) on this side to help the springs.

The other direction, the rebound side, of the shock damping rate is just as important however, as this controls the rate at which the springs push the car back over after the springs have been compressed with load. When this rate is too much, the car will sink on rough roads or vigorous maneuvers, reducing the effectiveness of the spring. When this is too low, the car will feel very unstable on the unloaded side, causing the loaded side of the car to get unpredictable with differing loads being put on the outside (loaded side).

All great handling cars strike a balance of all these rates to come up with a car that is predictable, stable, and responsive.

This is also why most all race cars have coil springs and not air springs (bags), as air springs are not constant, and vary greatly with temperatures and other factors, even though it can be used to make a very smooth comfortable ride by isolation of the road, and can be made to vary the spring rate simply by adjustment of the air pressure within, but the balance that is required for race conditions are never met with variables.