Koni / Bilstein Shock Help

[Banjo79]

Surely you have those spring rates wrong. Think it's 9/9 for the comforts. If not, definately can't wait for the review!

 

[HollySSV]

Yeah sure did, I didn’t know I owned a Lexus IS200. Just edited the post

 

[[paradox]]

Surely you have those spring rates wrong. Think it's 9/9 for the comforts. If not, definately can't wait for the review!

the comforts replaced the greens (and across others), and 10kg front back was what i was advised, given also i have a sedan not wagon.

 

[Banjo79]

Yeah, 10/10 is standard, got that one wrong. Just curious, do the comforts come with those good looking MCA strut top/tower mounts and camber washers and how are they going in general?
Also, anyone getting MCA who has a wagon, you might like them/fitter to put access holes in the "polystyrene like" boot surround. They probably won't want to, as its hard to get neat and the tie down points need to be unscrewed and floor side panels removed. I did mine myself with a drill, but its rough and butchered as the polystyrene doesn't drill even remotely neat. Can't help think a hot rod pushed through might give me something that resembles a round hole. If its not large enough, you have to feel for the hex head with the tool, like I do, can't see it. Also if you were to cut about 3mm off the rear adjustment hex tools, you could leave them in without them touching the boot floor when closed. Would have been icing on the cake if those 2 jobs were done for me.

 

[RevNev]

Josh at MCA said the Pro Comfort kit is more suited to daily driving, with 10kg Front, 10kg rear springs.

A 10kg spring is about 550lb and King front on the top are 220lb rear 500lb. That's massively stiff in the front, (track stuff) and the car will understeer like a pig with that front to rear spring rate bias. Unless the 10kg spring means something else, King's on the soft end are 120lb front and 300lb rear. King's are stiffer than stock springs so how's a linear spring more than double the rate (stiffness) ride like a stock car, they're dreaming!

 

[Skylarking]

I always thought spring rates were measured in kg/cm or lb/in and they were either linear (constant) rate or variable rate. For variable rate springs, the manufacture often provided graph to reflect the load against deflection, that was the case in the late 90 when I was playing with suspension)

So if someone mentioned a 10kg spring to me, I’d think that was the weight of the spring itself

Why is it that manufacturers now seem to want to dumb things down and the buying public just swallows such tripe

If someone mentioned 500 lbs, I’d think they were just being a little lax in not using the correct lb/in term as no car spring can weight in at 500 lbs

 

[Banjo79]

A 10kg spring is about 550lb and King front on the top are 220lb rear 500lb. That's massively stiff in the front, (track stuff) and the car will understeer like a pig with that front to rear spring rate bias. Unless the 10kg spring means something else, King's on the soft end are 120lb front and 300lb rear. King's are stiffer than stock springs so how's a linear spring more than double the rate (stiffness) ride like a stock car, they're dreaming!

I was certainly skeptical with having the same rate front and rear, but when I had a look at older Commies and other makes, the spring rates are all over the place, so it gave me confidence that thought has gone into it. Plus I was triple assured by the man himself, that they're the optimum starting point. I could not talk him into a +1kg bias to the rear of my wagon, done preferrably with a 10kg front, unless I had a constant load in the boot .I can only comment on the Prosports with 11/11kg and with delivered damper settings, but under most driving conditions, steering is neutral. A definate improvent over stock understeer. Add about 3 clicks of damping to the rear, or subtract 3 from the front and its mild oversteer and vice versa. Its actually been good to tailor the front and rear specifcally for the wearing tryes. Getting two new front tyres tomorrow, so will probably have another fidle to get things right.
Re. Procomforts on 10kg linear springs, with it being less than 10% reduction in spring rate (and most likely damping) from mine, I have no idea how they could be anywhere near stock comfort levels, or B8's with anything progressive. The damping is wonderfully plush, but you still know you have the car on steroid springs. Paradox, how do yours compare to oem/non-oem suspension?

 

[RevNev]

I always thought spring rates were measured in kg/cm or lb/in

Like tyre pressures expressed in psi, spring rates are most commonly expressed in lb/in even Eibach coil over springs. It's pretty "oddball" for an aftermarket suspension specialist expressing spring rates in kg's although it's common for car manufacturers to do so.

I was certainly skeptical with having the same rate front and rear, but when I had a look at older Commies and other makes, the spring rates are all over the place, so it gave me confidence that thought has gone into it. Plus I was triple assured by the man himself, that they're the optimum starting point.

In a VS Commodore live axle race car with a cast iron (heavy) V8, we'd run 750lb front springs and 350lb rear on coil overs. In a VZ with IRS and alloy V8, we'd run 600lb front and in the stock location 1100lb rear springs. On coil over rear IRS springs, we'd run around 550lb springs. The race car will also run 5 degrees of negative camber at the front and 4mm toe out and on the street, drives like a bone shaking and tram lining animal. A Commodore set up for optimum race track lap times on the street, is virtually undrivable and feels like serious bucket of sh*t!

FE2 is the stiffest VF with 3.7kg front springs and 7.6kg rear. FE3 has the same springs, softer shock valving and stiffer sway bars with the rear bar massively stiff to minimise understeer. King Springs total rate are around 4kg front and 9kg rear, so King's stiffened the rear more to minimise understeer for a road car setup that can't use excessive front camber like you can with a race car setup.

Shocks affect transient suspension movement, so softening the dampening with a stiff front spring will minimise "turn in" understeer but when the shock takes a set mid corner and ceases functioning and the spring is solely maintaining the vehicle "roll axis", the car will understeer mid corner with overly stiff front springs. Turn in and steady state cornering are two different things.

Running the same spring rates front and rear on a VF Commodore isn't a set up made with much intelligence or knowledge of the chassis dynamics of that particular vehicle. Holden and King/Monroe's approach is right for a road car and this 9/9, 10/10 stuff is wrong in my opinion.

 

[Skylarking]

It's pretty "oddball" for an aftermarket suspension specialist expressing spring rates in kg's although it's common for car manufacturers to do so

It does upsets my OCD when rubbish measurements are provided.

As is, car manufacturers want to keep their info proprieatary so probably use meaningless numbers to describe things. Id love to know spring rates, sway bar rates , etc for FE1, FE2 and FE3, something easily measured but not easily found...

As is, a commodore weights in at 1800kgs so calling a spring 3.7 kg is meaningless. A 3.7kg front springs make no sence whatsoever unless it is indeed the spring weight they talk about. But the physical spring weight isn't proportional to spring rate (which depends on wire diameter and winding diameter).

Assuming 50/50 weight distribution front/back and left/right, that would put 450kg of weigh on each spring... So with a 3.7kg springs, there is no way to calculate how far the spring would drop with the static weight of the car on it. You can't work out the ride height, preload, unbound compressed length, etc without the spring rate (and graph if if a variable rate spring)...

Yeah, the spring manufacture knows all these parameters and probably provides them but what is the real point to dumb things down so much that a spring is desribed by weight? So in my mind, 3.7kg is a bullshit measurement when springs are being discussed...

As to the vehicle behaviour w.r.t front and rear spring rates, front and rear sway bar rates and alignment issues and how this relates to vehicle dynamics for track verses road, thats great info. That's what people should focus on. If only more of such was offered and manufacturers stopped abstracting stuff, vehicle owners would know more than just to pull things from catelogs. But its all about the sell and owners manuals dont describe how to adjust rocker clearnances and mire, just not to drink the battery acid

For me, the factory suspension tune is almost perfect though i would have liked the car to sit just a little lower and be a little more compliant via taller sidewalled tyres. At the end of the day, our local roads aren't best suites to skinny sidewalled 20" tyres and stiff high performance track styled suspension tune would already rattle appart the commodore body which was never spqeek proof to begine with

 

[RevNev]

our local roads aren't best suites to skinny sidewalled 20" tyres

20's look good and the steering response is slightly better, but I think a good 245/40 18 on stock SS/SV6 wheels feels the best with a bit of sidewall to soak up the bumps and road irregularities. 20's are pretty harsh and aren't the most comfortable and they're the slowest on a race track. When a low sidewall tyre loses traction on a race track, the car slides suddenly like driving in the wet. All taller sidewall tyre is more like driving in dirt when they break traction with more time to catch it and control the slide. A car that slides suddenly and unpredictably, doesn't give the driver much confidence to push it hard and drive on the edge of traction, hence slower lap times in most cases.