KW V1s in an e46 quick review

[nitrojunky]

figured i'd post this up as i relied heavily on web reviews in making my decision, so i'll contribute back.

car stats:

e46 330ci (pre-facelift)
manual trans
sports package

relevant mods:

mahle HD FCABs
mahle HD RTABs
TMS RTAB limiter shim things
MPSSs mounted on stock style 68 wheels
yellow stuff pads and some good rotors

while i seriously enjoy driving the car, the shocks on my trusty e46 330ci daily driver were shot after 95kmiles. also, while it was predictable at the limit, i found it allowed way too much body roll for my taste. i'm not a fan of needlessly lowering the car and understand the benefits of having shocks intended for certain springs so i decided to go with some coilovers. after watching some KW V3 morph my friend's 996TT from a scary SOB to something which handled almost as well as my C6Z... and after reading the reviews i could find, i decided to give the KWs a shot. considering the small value of the car, i decided that i didn't need the added adjustability of V2s or V3s and went with the V1s.

install comments:

not incredibly difficult, but not easy. KW instructions are teh suxor. i work very slow and methodically and completed it in about 12 hours. front was quick and easy, rear was a PITA. i took good measurements and applied some math and was able to acquire the desired ride height in a single iteration. i expect most won't do that and will spend several iterations adjusting to the desired height. my biggest complaint: the rear spring perches are such that it either requires someone with incredibly strong hands to move the collars (the tool won't fit) or removal of the springs is required for adjustment. fortunately, i'm the former, but an inordinate amount of time was still spent alternately turning the collars and shaking out my burning forearms. i wish KW would have engineered a way around this.

post install comments:

what can i say; they were exactly what i was looking for. i've owned several very high performance cars including the C6Z (with revalved DRM bilsteins) and am accustomed to a car which can turn very well. while my e46 isn't at the level of my C6Z, it now corners much flatter and predictably. recovery from slides/drifts is drama free, rebound is nice and tight, yet
composure on bumpy pavement while at the limit is excellent. these are significantly stiffer than stock, but i don't find them to be harsh. keep in mind that i like my suspensions stiff and that i don't deal with potholed pavement as do many northerners, therefore opinions may vary on harshness.

ride height:

i chose to set up my car with the stock rake and ~1/2" lower than stock sport suspension. i could have set it up higher than stock if i chose and the specs indicate that one can lower it well below stock. i'm very happy with the fact that i'm not buying camber plates and dealing with changing my suspension geometry in order to get a good spring rate. i got the car aligned post-installed and everything but the rear caster is in spec; i do not believe this is adjustable nor do i believe this is an effect of my mod. caveat: i do have the rivets at the top of my front towers popped to get the front back to -1.0° front camber.

bottom line:

excellent suspension at a reasonable price. pretty stiff, but i'd imagine the target market doesn't drive buicks.

[weedshoes]

Rear caster? :shifty

[nitrojunky]

yep. rear caster. i don't think it's even adjustable on this car, lol. for some of my other cars it is.

http://forums.corvetteforum.com/1570126163-post11.html

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i imagine the rear trailing arms in the e46 would make rear caster adjustment a kinda iffy proposition, heh. though i guess you could shim the RTAB mounts down some. hmm. i'll have to check if the slight lowering is what did it.

[weedshoes]

I think rear caster only applies to cars with rear steering.

You could affect the inclination angle by changing the length of the control arm, but without a steering axis there is no caster.

[nitrojunky]

Z06 has two wishbones (or wishbone like things). it has caster, and it can be adjusted on the Z (or other C5s and C6s); depending on the rear suspension geometry, toe changes as you compress the suspension... therefore caster has an effect. see the linked thread and the pics below; it's adjustable in corvettes. the toe adjustment are the arms which look like they come off a steering rack. i imagine many other cars are the same way.

506201

the shop had a caster spec for the e46. i don't claim to be an expert but i think about things a little; here's my thought process:

i agree that it was weird that it should exist for this car, but it could be that the trailing arm's angle on a slightly lowered car makes for a reduced 'caster' angle. spec was listed as 5.1° and 6.1° and my car was at 5.0°. and thinking about it, it would make sense that lowering the car would reduce the caster angle. regarding steering axis, as the suspension compresses, there is a steering axis about the lower control arm and upper ball joint of the e46 rear suspension; IIRC, it does have an upper ball joint allowing the rear wheel to steer some (2 degrees of freedom as does the RTAB). meanwhile the lower control arm is surprisingly flexible. just took a look at the rear suspension of the e46 (happens to be sitting on up on the lift this evening) and with the springs loaded with the car's weight, the upper rear control arm is almost parallel (but is slightly lower at the wheel side than at the attachment point) while the lower control arm is much lower at the wheel side than at the attachment point. as the suspension is compressed, the lower control arm and the upper control arm will approach parallel at different rates (they're different lengths and start at a different angle with the bottom of the car), but the effect would be pushing out the rear wheel a little while the front of the lower trailing arm stays fixed. because of the geometry, the lower control arm will push out the bottom faster than the upper control arm pushes out the top ('faster' per unit of compression), thereby simultaneously increasing camber and pointing (steering) the wheel toward the middle of the car... a desirable effect when body roll is encountered in a hard turn IMO. my estimations are that as the suspension compresses further, the upper control arm will actually start to pull in the top while the lower control arm continues to push out the bottom and this will continue all the way until the shocks hit their stop. going further with the thought experiment, from the geometry i expect the effect of the bottom control arm >> the effect of the top as far as toe is concerned, therefore toe will actually continue to increase until you hit the stops though the increase per unit of compression reduces as you get close to fully compressed as the lower control arm will be nearing parallel with the bottom of the car.

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based on the above, the caster could be adjusted by shimming down the RTABs' attachment plates, however i need it to go the other way. fortunately, mine are so close to one side of the spec, i don't think it'll be an issue and now that i've thought about it a while, it'd be back in spec if i raise the car 1/2". my caster is 5.0° on both sides (perfectly symmetric to the least measure of the rack); the main issue would be if it weren't symmetric which would suggest bad RTABs or bent control arms having adjusted the ride height different from one side to the other. or maybe something else, but those are the first which come to mind. cool that someone brought it up as i hadn't thought about the caster spec since getting the car aligned. good to close the book on that one and made me research a thing or two on caster.




all that said, the point of the thread is to discuss the V1s. IMO they're an awesome mod for DD and i especially wanted to convey that one can retain the stock ride height of a sports suspension e46 should they choose to since i was unable to locate that detail. also the other main point: one can get the alignment in spec (except for rear caster) without buying expensive plates and lower control arms when lowering a sport suspension e46 0.5".