Raising the car = better handling???

[quang]

Hi everyone,
So i recently went to the suspension shop (won't name it) to get a wheel alignment.
upon have a discussion with the mechanic, he was saying that given my setup (buddyclub N+ coilovers, adjustable rear camber upper arms, adjustable camber & caster front upper arms, relatively new bushes, lowered to 2-2.5 finger gap "1inch" above the tyre) if i were to raise the car would ride and handle better, not to mention it would probably solve my scrubbing issues.

i'll say now i have a very basic understanding of suspension setups but general knowledge would say lowering the car, lowers centre of gravity hence less potential for bending moments and weight transfer, keeping the car flatter allowing for more grip and therefore better handling.

The reasoning the mechanic gave me was something along these lines, (sorry i can't recall everything he was saying and trying to search on the net isn't coming up with what he was talking about):
Essentially given the setup i had, by lowering the car i had affected the SRI/A? (steering something inclination/angle). These angles cross each other and the centre of gravity lies in line and above with the crossover point, I had moved the crossover point away from the centre of gravity.
For ideal handling, the closer the crossover point is to the centre of gravity the better the car behaves, this is achieved by changing the SRI/A. Ideally you want the centre of gravity below the crossover point, but this is practically impossible for manufactured cars. Even F1 cars can't achieve this but get close.
Through raising my car, i would be bringing the crossover point closer to my centre of gravity, and allow the suspension to travel properly and hence overall increase the performance of the cars handling.
Not to mention gain back additional adjustability for camber and toe as it currently can't go any further for some reason. The front camber can't move any more from -0.5 and the rear toe can't go any less that 1.5mm toe in (3mm overall).

Sorry for the massive post but does this make any sense to anyone?


Thanks

[trism]

Yes this is correct.

Centre of gravity is all well and good, but do some research on roll centres, as well as things like suspension and steering arm angle, drive shaft angles.

There is a lot more to good handling than just lowering a car.

[senna]

Yes, listen to your mechanic, he knows what he is on about!

By lowering the car too much the suspension is working on the limits of what it was designed to do, so your bushes and ball joints are close to being bound up.

You have to remember that suspension arms work in an arc, so when they move up and down, the hubs are also moving in and out and the rack ends are also pushing the steering angle in and out. This is where bump steer occurs.

Centre of gravity is another important thing, but as you've learnt already there are many more things to consider about suspension than just looks.

[quang]

ok, so my question is, my car is still 1 inch above the tyre, realistically only about 1-2cm lower than stock and IMO not vey low.
I realise since changing to coilover it may have a different geometry to the stock suspension but wouldn't a coilover be designed lower the car and hence not have such a negative impact on the handling of the car?
If i were to raise the car the amount the mechanic was recommending i would be raising it higher than stock height.
Also, what about some of the ozhonda members race cars? they are all low, i do realise they may have some extra components for adjustability.

[e240]

I reckon 1" is fine.

Some race cars tend to run roll centre ball joints which compensate the roll centre for lowered cars.
http://www.ozhonda.com/forum/showthr...ntre-Adjusters

Some explanation
http://www.suspensionparts.info/showthread.php?t=27475

[munkaii]

Roll center location relative to cg dictates the extent of body roll acting on the vehicle (in a simple sense). Lateral cornering forces are applied at the cg location, resulting in a bending moment acting around the roll center location. The magnitude of this bending moment dictates the amount of body roll and lateral load transfer. You want to minimize this as much as possible.

On the dc5 (hopefully this is the car you have as I haven't read thoroughly), lowering the vehicle lowers the cg location, however given the dc5 geometry, it also lowers the roll centre location. Going too low increases the distance between roll center and centre of gravity.

This is why after market manufacturers have designed so called "roll center adjusters". What these serve to do is to lower the suspension pickup point of the lower control arms, thus raising the roll center position and closing the gap between rc and cg.

So in regards to raising your car, raising your car will raise cg but also raise the roll center. What you want to find is the balance between low cg and higher rc.

[munkaii]

Cars running lower generally have roll center adjusters or offset ball joints etc to assist with steering geometry and body roll characteristics.

[senna]

ok, so my question is, my car is still 1 inch above the tyre, realistically only about 1-2cm lower than stock and IMO not vey low.
I realise since changing to coilover it may have a different geometry to the stock suspension but wouldn't a coilover be designed lower the car and hence not have such a negative impact on the handling of the car?
If i were to raise the car the amount the mechanic was recommending i would be raising it higher than stock height.
Also, what about some of the ozhonda members race cars? they are all low, i do realise they may have some extra components for adjustability.

What we are talking about here is really about maximising the potential of your set-up. This does require additional components like roll centre adjusters, extended tie rod ends with shorter rack ends etc.

The drop on your car isn't extreme, i don't think your current set-up will be terrible, but i'm not sure why you can;t get more than -.5 camber on the front...

[munkaii]

Whoops thought I was posting on clubitr. Concept is pretty much the same though.

[quang]

Hmmm, thanks for all the info guys!!
Senna, for the fornt camber, it seems to change with every place i go to. Some can get slightly more camber but it seems to max out at -1deg. which i think is wrong, I have SPC caster and camber adjustable upper arms where the camber is supposed to be adjustable by up to 2.5 deg.

So for the people with a basic setup similar to mine. Are there any basic rules of thumb for car ride height settings for civic's in particular?
Given standard arms and the like, would there be an optimal height to make best use of the standard geometry?

[quang]

all good, been doing some reading and slowly figuring things out. thanks for pointing me in the right direction guys!

However, has anyone heard of essentially the geometry "locking" so no more adjustment could be made. The story i keep hearing is that the front can't be adjusted anymore.
Can anyone confirm the points where the front camber adjustment is? It's on one of the lower control arms or steering arms isn't it or in that area, sorry may have the wrong terminology?

[lilthug]

good information here


good read from that links e240 provided