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TimCaruso26

Should i get it lowered?

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I will soon be replacing the struts on the car and i was wondering if lowering it 1.5 inches or so would be beneficial. What do you think?

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If you have to ask, then the benefits are probably of no use to you.

To name just a few...

Cons: Reduces drivability on rough roads, reduces ride comfort, increases amount of roll (unless if better sway-bars are installed as well).

Pros: Sharper cornering, looks (opinionated), Lower center of gravity, quicker weight transition for turn in/slalom.

Really though, try a search next time. this has been covered a million times (not just for 2002s, even a basic search will help). In my honest opinion, if you have to ask, than there is no real compelling reason to stray from stock. Consider your driving style and what you are trying to achieve. I personally love a car that handles extremely well, and will eventually go an inch lower, but the ability to speed over bumps and rough roads without worrying of bottoming out means that any lower would actually make the car slower. I love stiff roll bars and just a minimum of lowering, with good struts and slightly firmer springs. Hard to beat for a street driven car.

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also changing struts doesn't lower the vehicle; changing springs does.

keeping that in mind, you must match your struts to your springs. No point having well dampened struts on soft springs; over-dampened cars are terrible to drive, as much so as under-dampened cars.

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Koni struts will lower your car 1.5 inches

Good point. I stand corrected.

I forgot the strut length determines ride heigh on the 02's. moving between cars too much lately at work that I forgot whats under my own baby xD

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Koni struts will lower your car 1.5 inches

Never heard of this and how does installing a higher rate lowering spring increase roll?

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how does installing a higher rate lowering spring increase roll?

The way that the suspension geometry is set up on the 2002 is in such a way that lowering actually raises the roll center relative to the cars height, therefore increasing roll. Lowering is not the same thing as lowering AND increasing spring rate. If you lower by means of increased rate springs, then chances are the spring rate will compensate for the increase in roll, but you will have a harsher ride also.

Also there is a noticeable increase in bump steer on a lowered 02, unless if corrected.

Some decent reading for those new to suspension setup.

http://www.bmw2002.com/documents/bmw-suspension.pdf

An excellent read for those who have a fair understanding of physics and engineering and who want to learn a TON about all kinds of suspension setup...

http://www.amazon.com/New-Directions-Suspension-Design-Making/dp/0837601509

Generally speaking, factories such as BMW usually get the suspension "right" from the factory. The only way to improve on it is to take out the understeer and softness that is left in place by the factory in order to compensate for amateur drivers. A couple of degrees of camber and a set of roll bars can completely transform a car from an understeering box of mush into a tail wagging happy drifter. You just better be ready for it when that rear end breaks loose.

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I will soon be replacing the struts on the car and i was wondering if lowering it 1.5 inches or so would be beneficial. What do you think?

yes?

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Koni struts will lower your car 1.5 inches

Never heard of this and how does installing a higher rate lowering spring increase roll?

Imagine a car with super soft springs. You hit a bump in the road with your left side tires. The springs compress easily, so the wheel and trailing arm rise a lot, but the corner of the car only rises a little. So very little body roll is incurred.

Now swap to super stiff springs. You hit a bump in the road with your left side tires. The spring barely compresses, so when the wheel and trailing arm rise to get over the bump, the corner of the car goes up nearly the same amount. This results in more body roll.

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Koni struts will lower your car 1.5 inches

Never heard of this and how does installing a higher rate lowering spring increase roll?

Imagine a car with super soft springs. You hit a bump in the road with your left side tires. The springs compress easily, so the wheel and trailing arm rise a lot, but the corner of the car only rises a little. So very little body roll is incurred.

Now swap to super stiff springs. You hit a bump in the road with your left side tires. The spring barely compresses, so when the wheel and trailing arm rise to get over the bump, the corner of the car goes up nearly the same amount. This results in more body roll.

What you said is correct... Sort of. Body roll is measured between the body and the wheels, not to the ground. In the example you mentioned, the softly sprung car actually exhibits more roll than the latter. You feel more roll in the second car.

We need to simplify here. Are we discussing cornering ability or straight line comfort? It is easy enough to set up a car that absorbs a bump as you mentioned but that corners flat. The key is in spring to anti roll bar ratio.

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Koni struts will lower your car 1.5 inches

tell us more....

perhaps you mean a shorter insert w/ a shorter strut housing?.like a coilover set up?

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Rocan: Thanks for the suspension book tip. I just bought Race Car Vehicle Dynamics (Milliken & Milliken, 1995) but have not started reading it yet. Have you read this and if so, how does the Colin Campbell (1981) book compare? If Colin's book covers additional aspects I will look into that as well.

I have long been interested in the old DTM E30's that had adjustable roll center height on the rear subframe. Perhaps some day I will build that into my car, but only when I know enough to know what I am doing!

Jake Larsen's Tour of the DTM Suspension

http://www.s14.net/jakesdtmtours/suspension.html

See the Trailing Arm Assemblies section, in particular slide 52:

http://www.s14.net/jakesdtmtours/image-html/sus52.html

Tim: To answer your question we need to know you purpose in lowering. Looks? Off-road capability? Spirited mountain driving? High performance driving on a closed circuit?

Fred '73tii & '69GT3 (both track-only)

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Millikens book is next on my list, so i cant compare them...

interesting stuff on adjustable roll center height. I absolutely agree with you; we need to know WHY you want to lower it in order to give you the pros and cons.

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If you have to ask, then the benefits are probably of no use to you.

To name just a few...

Cons: Reduces drivability on rough roads, reduces ride comfort, increases amount of roll (unless if better sway-bars are installed as well).

Pros: Sharper cornering, looks (opinionated), Lower center of gravity, quicker weight transition for turn in/slalom.

Really though, try a search next time. this has been covered a million times (not just for 2002s, even a basic search will help). In my honest opinion, if you have to ask, than there is no real compelling reason to stray from stock. Consider your driving style and what you are trying to achieve. I personally love a car that handles extremely well, and will eventually go an inch lower, but the ability to speed over bumps and rough roads without worrying of bottoming out means that any lower would actually make the car slower. I love stiff roll bars and just a minimum of lowering, with good struts and slightly firmer springs. Hard to beat for a street driven car.

Hmmm ------ if lowering a car makes it lean more, then why don't we make racecars as tall as possible.

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Unless you want it to behave exactly as it did off the dealer lot, just do it. You won't regret it. H&R or Eibach springs. NO "stage 2" stuff. The numbers don't matter to you, we can see that. Do an uprated HD strut/shock, and the above springs. Its a tried and true combo.

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