lowering e36

[sik_bmw 0]

wanting to lower my bmw e36 so that the guards sit just above the wheel at the front and that the back is at a relative height so that the car sits flat on the ground, not angled downwards or upwards etc. I heard jamex super lows will do the trick but to do this will i need shorter shochs or can i put them in with the factory ones? any help would be great, cheers Sives

[Miller 0]

No you wouldnt need shortened shocks. But i wouldnt touch Jamex. I have had them in my e36 and yea sure they were low, but they handeled like sh*t and sagged so much that as soon as you had 5 people in the car, the car sat on bump stops at the back. If i were you i would go for a set of H&R springs. It may sit a little higher in the back than jamex, but it is alot nicer ride and doesnt sag. Hope this helps. lol

[Nobimmer 694]

Super lows probly need shock shortening.$112 inclusive at Autolign.

[Miller 0]

Na you definatly dont need shortened shocks for superlow jamex's or H&R's. I had them both in my car and they were nice and captive.

[sammaw 0]

I had super low kings in my 328 coupe. To be honest i would not do it. BMW mechanic told me either buy new springs or a new diff. Ended up with some progresive springs which handle far better than the superlows.but if you really want it low and want a set of kings PM me maybe we can work something out

[318isCoupe 0]

I've got OE Motorsport springs in my coupe.. look under the rides section.

Low enough in the back for me, but the front needs to come down 25mm or so.

[Turning_Point 0]

No you wouldnt need shortened shocks. But i wouldnt touch Jamex. I have had them in my e36 and yea sure they were low, but they handeled like sh*t and sagged so much that as soon as you had 5 people in the car, the car sat on bump stops at the back. If i were you i would go for a set of H&R springs. It may sit a little higher in the back than jamex, but it is alot nicer ride and doesnt sag. Hope this helps. lol

no offense man, but i find that incredibly hard to believe.

with 5 people in my car theres still travel in the suspension in the rear. and ive got ...red (so i assume jamex) springs...which maybe super lows..not sure. but basically..they were cut when i brought the car ( wasnt aware of this )...so i decided to cut it some more (wait as people give me the evils ) (its basically half the original size of the super low) and its on standard shocks too.

but if you want a good height at the front..jamex super lows (i assume) at the front is good as for what u want.

[318isCoupe 0]

What would you suggest for the front of my Coupe to bring it down to a similar wheel-tucking height as the back?

[Turning_Point 0]

if your talking to me...

(cant have a bma that doesnt tuck, unless its a m series one...thats my personal opinion ) anyways..like my above post, mines cut in the rear...and if you dont mind a tiny bit of bumpyness ..and im not understating that ...then crank out the angle grinder..its really not as bad as people perceive.

otherwise if you want to go legit, get some super lows, look like uve already got some in there...and get your shocks shortned, as it seems the shock travel, play a big part into how much the springs compress.. but to be honest super lows...arent "super" low at all haha.

[318isCoupe 0]

if your talking to me...

(cant have a bma that doesnt tuck, unless its a m series one...thats my personal opinion ) anyways..like my above post, mines cut in the rear...and if you dont mind a tiny bit of bumpyness ..and im not understating that ...then crank out the angle grinder..its really not as bad as people perceive.

otherwise if you want to go legit, get some super lows, look like uve already got some in there...and get your shocks shortned, as it seems the shock travel, play a big part into how much the springs compress.. but to be honest super lows...arent "super" low at all haha.

It's actually just got the OE Motorsport suspension all around

Will leave the factory springs in the back for now, as it sits pretty low..

So maybe a set of superlow's in the front? or what's the deal on getting the factory springs compressed?

[Turning_Point 0]

haha oh yeah thats pretty good suspension then i assume, dont want to fiddle with that too much.

yeah super lows would go alright..and good thing you mentioned that, i knew i forgot to mention something.

compressing springs in a mechanical sense, is as bad as cutting springs as the heat tempering destroys the spring's spring rate properties and so forth (gypsys at spring compressing places will tell you its perfectly fine and nothing changes...but how could shorter springs have the same spring rate as opposed to when it was original..go figure), its only advantage as it retains the shape of the spring (pretty useful for rear springs since their a weird shape)

you can get your springs compressed at snells springs in penrose (best place as they will do any amount of compressing).. for already lowered springs id only compress about 50-60mm any more, and you'll get cronic saggage. costs about 130$ a pair, and you'll have to leave them overnight

[kerrynzl 3]

It's actually just got the OE Motorsport suspension all around

Will leave the factory springs in the back for now, as it sits pretty low..

So maybe a set of superlow's in the front? or what's the deal on getting the factory springs compressed?

When You Refer to "Compressed" , I hope you don't mean "clamping "them down [i've seen this butchery done with wire ties, and also U clamps]

Seeing that you live in Tauranga, I would reccomend getting Smith Engineering on Maleme St to re-set the fronts 25mm lower. The Motorsport Suspension is a pretty damm good package as it is [you just want to change the appearance,by lowering it]

I have a similar spec car that I personally think can out-handle most drivers [our enthusiasm always exceeds our ability]

PM me if you need any suspension help [i'm also in TGA]

[kerrynzl 3]

compressing springs in a mechanical sense, is as bad as cutting springs as the heat tempering destroys the spring's spring rate properties and so forth (gypsys at spring compressing places will tell you its perfectly fine and nothing changes...but how could shorter springs have the same spring rate as opposed to when it was original..go figure), its only advantage as it retains the shape of the spring (pretty useful for rear springs since their a weird shape)

When a spring is re-set it is only heated to approx 400c [while clamped at a different height] the spring rating [eg lb/in] stays the same, so if the load is the same[at the sping] the sag will be the same,but from a different static height [therefore sitting lower]. A shortened spring has the same rating as the original [as long as it isn't cut, eg same length wire]

When you cut a spring it gets stiffer because the load is 'divided' by the length of the wire [a torsion bar/sway bar works the same, the shorter it is the stiffer it is]

[Turning_Point 0]

nice ^^. just gotta get that around my head. you seem very knowledgeable

[kerrynzl 3]

Thanks for that! 3 pedals

One thing that also needs to be taken into consideration is the 'motion ratio' of the suspension [leverage ratio] eg; on a falcon it's 50%, so to lower the front 50mm requires shortening the spring height 25mm

most macpherson struts are approx 90% [because of the angle of the strut]

[Katalyst 0]

how do u find out the motion ratio??

[kerrynzl 3]

With suspension the correct terminology is "Motion Ratio".

With a Mac Strut the ratio is approx 90% depending on the "king-pin Inclination" [another term], the more the Strut leans inwards the lower the%. [similar to laying down the shocks on an early motocross bike]

the easiest way to measure the motion ratio on a Strut is to; measure the lower leg between pivot points. then; measure from the inner pivot to a right angle point on the strut.

Usually rear springs even though they're mounted inboard are 1:1 because they attach directly to the diff [live axles] [Holden Torana's have the springs mounted to the trailing link,so they act the same as a wishbone]

Don't confuse "Spring Stiffness" with "Roll Stiffness",Swaybars control roll stiffness but dont suspend the car. Moving springs inboard on a live axle affects roll stiffness,but not straight line 'spring stiffness' [try cornering fast in a drag-car]

With all these leverage "ratios",all the car cares about is the "wheel rate" which is the spring rate x the motion ratio /squared

eg: with a 50% motion ratio [or 2:1 to make maths easier] to get 100lbs/inch at the wheels requires a 400lbs/inch spring

A falcon with a 1200 lb spring [50% ratio] has the same wheel rate as a Commodore with a 370lb spring [90% ratio]

The wheel rate is 300lbs/inch

easy huh!

[Katalyst 0]

yeah....?

where r my picture books gone

[kerrynzl 3]

With the early motocross bikes, I used as an example to show how even though the attachment point of the shock is unchanged [on the swingarm]the M/ratio can be altered [as you confirmed by the suspension being softer][the same method for a different reason]

Struts are the same. When you add more neg-camber,it is theoretically altering the wheel rate [by a miniscule amount]

When you measure the strut, hold a tape at a 'right-angle' to the strut [on struts with a dog-leg at the bottom,eg: commodores or E36's you have to find an imaginery centerline between the upper & lower pivots] on wishbone lower legs you have to find a centerline from the front & back inner pivots [measure at right angles from this pivot-line]

some people mistakenly measure the ball-joint at the nut [it doesn't pivot from there!]

Theirs nothing wrong with your terminology: Gearing,Leverage,or Motion-Ratio [the fact that you understand physics/maths regarding suspension puts you ahead of most people] with 200 views on this thread so-far ,I could be helping someone out there [therefore I prefer to use the automotive terms,thats all] No offence intended!

[kerrynzl 3]

I crawled under my E36 last night with a ruler [highly accurate]

The lower wishbone is 335mm between pivots [approx]. From the inner pivot to the centerline of the strut [at a right angle] is 300mm [approx]

100% divided by 335 multiplied by 300 = 89.55% [approx 90%]

to calculate the wheel rate with a 250lb would be as follows;

250 x [0.9 x 0.9] = 202.5 lb's at the wheel

to get the same wheel rate from a falcon with a 50% m/ratio we reverse the maths

202 divided by [0.5 x 0.5] = 810lb spring

an XA falcon V8 has a 750 lb spring [no wonder they drive like a barge]

I hope this clears up a questions.

[kerrynzl 3]

Yep sure does, the motion ratio is the dominant factor, actual strut inclination is minor (unless it were a significant angle like 15 degrees or more).

Out of interest I am about to fit modified M3 top mounts to my 328 to give me more caster. The strut is will be more upright as the top mounting point moves outboard.

My pick is this will reduce camber change under braking - is this correct

If you move the tops outboard you'll end up with more [static] negative camber. I believe M3's had offset lower legs/bushes to counteract this [can anyone confirm this?]

All Mac/Struts induce negative camber under compression [it's basic triangulation]

[kerrynzl 3]

The Mac/Strut is a basic triangle , between the upper pivot ,lower inner & outer pivots [two sides of this triangle are fixed length] the lower leg swings on a radiius when the strut shortens ,making the angle more acute ['dynamic' or induced negative]

Because the M3 is lower ,maybe this is to restore the camber back to a sensible ammount for a road car [someone might know] then the camber is dynamic [induced] instead of using static negative camber

Two things happen when more caster is used;

Less neg is required.As the outer wheel gets more negative,and the inner wheel gets more positive when the wheels are turned into a corner [the steering gets very heavy with more caster]

Also more dynamic caster [from altering the top mount in relation to the lower wishbone] creates anti-dive; under braking the Caliper [mounted to the strut] tries to stand the strut upright [negative caster], while compression of the strut tries to lean the strut backwards [positive caster], these two forces try to counter-act each other creating anti-dive! another way to engineer anti-dive is to lower the front pivot points of the lower wishbones

[kerrynzl 3]

One thing that can't be changed is the angle of the Stub axle to the Strut, so any change in the position of the top plate will affect the static angles of the wheel [caster/camber]

when BMW moved the tops out [on the M3] they would've needed to move the bottoms out also to maintain correct camber [hence offset bushes] maybe this was to increase Track Width which helps a car corner faster [i'll need to measure an M3 to confirm this]

9-1/2 degrees caster is about the same as an NZV8 touring car, which is ok with power steering

Too much static negative isn't too good for tyre wear [camber thrust] or straight line stability [tracking over bumps etc] thats why German manufacturers use a lot of caster on road cars

Camber thrust is like 2 cones rolling towards each other [thats why toe-out is used on race-cars with lots of negative]

If you increase the roll-stiffness [sway-bars] ,less static negative is required [for maximum cornering 1/2 degree negative at the tyre footprint is all that is needed at maximum bodyroll/cornerng speed]

[Miller 0]

Sorry but i cant be bothered reading the whole thread again, but have you purchased any springs yet? I might have a set of H&R's you can buy off me. There 60mm front and 35mm rear. Makes the car sit really nice. Just PM me if you are interested. Thanks

[330itis 15]

i cant even be botherd reading this all... but go the JAMEX progressives. goes really low and handles like a dream.

u cant tuck the wheel in the front on any e36 because the front chasy rails will be way to low to the ground. mine sits at 80mm as is.

ALWAYS BE AWARE OF THE LOWEST POINT OF THE CAR.