dragonfly2k3

Ok, i did a quick search and didnt find much that was well organized or intelligent.
The point of this thread is to have informative information that someone can back up with understandable reason or other proof. I dont want any "My cousin had this and came into the trailor park at 90 and didnt slide." None of that ****.

Now, what I want to know is, What works?

Strut tower bars: Upper or lower, what styles work, what styles are bling, how do they work etc.

B/C Pillar Bars: What style works, Do any work?

Sway bars: We know these work, but how thick is too thick? Lets talk about how and why they work as well.

Suspension bushings: What bushings are best to be poly, any that should be left stock?

Camber Kits: Who makes the best ones? Any better than others? Issues with holding setting?

Suspension Geometry: Lets try to get a lamens terms definition of different geometry, What does each setting do, etc.


I am going to keep my opinion out of this. I think I know a couple of thinks; but i dont want people who think they know in here. I noticed there is not a very good faq in the suspension forum, so lets try to keep this together and get lots of good info for later. Ill edit this and add into to appropriate sections as it is verified.

dragonfly2k3

up and up.

PatrickGSR94

iTrader: (1)

Strut tower bars, or in most Hondas, shock tower bars: they don't do a damn thing on a street car. Really, a street car will not see the driving conditions of a track where they will make somewhat of a difference. But the ones that work best are the ones that are more solid... like the stock front upper bar on GS-R's and ITR's for example. Oh, and there's really no such thing as a lower shock tower bar, since there's really no place to tie the bottom of the shock towers together, and you certainly can't tie the bottoms of the shocks themselves together.

We all know the 22mm ITR rear sway bar works great, as does the 23mm JDM ITR bar if you want to spend some more. But I think much larger than that starts to get into the overkill range. Remember, the bigger/stiffer the bar, the closer you're getting to a solid beam axle (like old early 80's Civics, 90's Chevy Cavaliers, almost all Chrysler minivans, etc.). The stiffer the sway bar, the more you limit the suspension on each side to be able to move independently. This can adversely affect ride quality if you're driving over uneven roads where the left and right tires are moving up and down at different rates.

B/C Pillar bars may help chassis rigidity a TINY bit, but are HIGHLY unsafe if you ever carry passengers in the rear seat. For the price of some of these "monkey bars" and "X-braces" and all this crap, you could just get a cage welded in behind the seats, which will do 100x more for chassis rigidity than bolt-in bars ever will, at a comparable price even.

Poly bushings are pretty much just junk, period. I have them on my 22mm ITR sway bar, but they are greasable and not really a load-bearing bushing like the ones in the LCA's or trailing arms are. But I had poly shifter bushings and those things literally disintegrated. I put new OEM rubber bushings back in and it felt tons better. Bottom line - for a street car, stay with OEM rubber or aftermarket hard rubber like from Mugen or HardRace. Delrin bushings are another possibility, but I don't know too much about them nor have I seen or read about anyone with extensive experience with them on the street or track. For a track car, spherical is the way to go to eliminate ALL slop, but the trade-off is a relatively short life span. I would highly recommend AGAINST spherical bushings on the street. Probably the most important bushing to NOT use polyurethane on is the RTA bushings. Those will bind up badly with poly and will adversely affect handling.

Camber kits - skip 'em, unless it's on a track car where you want to ADD more negative camber than the suspension geometry already allows, for better handling. When you lower a car, both toe and camber change. Toe is what eats tires for breakfast, and a simple 4-wheel alignment can fix that right up. With regular tire rotation, you should have not have a problem with tire wear because of negative camber. And your car will handle better.

For suspension geometry and terms like camber, toe, caster, etc. there are good resources out there like on tirerack.com that can explain those. Basically negative camber aids handling around corners. Toe affects straight line stability, and caster can affect both straight line stability and cornering, since positive caster actually makes the outside tire's camber go more negative as it turns.

VTECIntegra9

bump for the time patrick took writing that.

PatrickGSR94

iTrader: (1)

haha yeah I had to hit Edit several times to insert other sentences or move stuff around.

dragonfly2k3

truth, theres alot of info there. i was hoping for this to be more active, but pat put in alot of time.

alphalanos

He pretty much explained it. Ill just say Tires and Alignment.

Targa250R

In for later. Someone bump this to remind me. I have a lot on my mind.

PatrickGSR94

iTrader: (1)

so what were you gonna say?

sg

patrick great writeup!

xd69

iTrader: (1)

Bump to see what else is going to be said...

SuperBADEK

Bump for great write up

johnlear

My personal experience with my DD CB7 accord is quite contrary to this. Both my front and rear tower braces made a very noticable difference to steering and handling response as well as a subjective feeling of improved chassis 'integrity' (for want of a better description, i.e. the chassis just feels stiffer, and better), though not much if any noticable difference to handling balance (i.e. didn't change understeer / oversteer characteristics). I'd recommend them highly.

Agreed, strongly. Tower braces MUST be RIGID in order to make any worthwhile difference. 'Rigid' includes not just the bracing bar itself, but also the brackets that attach the bar to the tower tops (flex is flex, your car can't tell where it's coming from). There are a lot of rubbish tower braces out there, and they give tower braces a bad name. My tower braces are home made, and very stiff, I can certainly feel the difference when I've temporarily taken them off for whatever reason.

I have to disagree. IMO the ARB stiffness cannot have any affect that makes the rear suspension behave more like a beam axle, no more than stiffer springs can do. In fact less so than stiffer springs because a stiffer spring is stiffer in both single and double wheel bump, whereas a stiffer ARB is only stiffer in single wheel bump (and in roll of course).

Keep in mind that the ARB is only a cross linked torsion spring, and has no affect on geometry at all. The real difference between an independant and non independant suspension is geometric (leaving out live rear axles that also have undesirable weight and torque reaction issues). Even if your premise were correct, beam axles are quite a good rear suspension system for FWD cars, many BMC Mini (i.e. the original Mini) racers ditched their stock IRS and substituted a beam axle...

However, I think we might need to differentiate between a proper beam axle located by radius rods etc and a 'trailing compound crank' axle where the axle is a sort of elongated 'U' shape' with a twistable beam connecting the two arms of the 'U' at the front of the 'U'. This type of axle is really a variation on a 'trailing arm' suspension that is geometrically very similar to the original Mini OE rear suspension and also to the front suspension of old VW Beetles. The flexibility of the 'beam' section of the 'U' allows independant movement of each wheel, as well as contributing some degree of roll stiffness (in addition to any ARB that may be fitted). The main reason these axles are used is because they are cheap (and rather nasty compared to better systems).

The reason a 'trailing compound crank' axle is geometrically similar to pure trailing arm suspensions (Mini rear / Beetle front etc) is that as the suspension moves vertically there is zero camber change, so, any angle of body roll results in the same degree of camber change at the rear wheels (e.g. 2° body roll would = 2° pos camber at the OR and 2° neg camber at the IR, which is bad in both cases).

Also the geometric roll centre is located at ground level (like with trailing arms), which makes it impossible to have the front GRC lower than the rear GRC (which is desirable) unless the front GRC is below ground level (which is undesireable).

Agreed, a stiffer ARB will increase ride harshness, but less so than an equivalent increase in roll stiffness achieved with stiffer springs.

I have a home made 'X' type brace fitted directly behind the back of the rear seat, that further improved what the rear tower brace did for handling dynamics (that large aperture between the trunk and passenger compartments does nothing good for chassis stiffness, and needs to be properly triangulated for better chassis stiffness). The nice thing about this particular 'X' brace is that it takes up almost zero trunk space, though it does mean I can't carry long loads into the passenger compartment (small price to pay for what it does).

Note that because of the open nature of the rear end of the chassis, hatch style bodies are inherantly less rigid than sedan bodies (all else being equal), and most hatches should benefit quite a bit from stiffening up the rear of the chassis. This would include rear tower braces and well designed 'X' style braces, and very much rear roll over cages, but some of the other braces on the market are not very effective (e.g. those bars that 're-inforce' the back end of the boot lip etc).

Whatever you do, you don't only need to improve lateral chassis stiffness (as a good tower brace does), but also to triangulate the 'back of the box' (which is more or less open on hatches).




Modified by johnlear at 12:56 AM 9/18/2008

PatrickGSR94

iTrader: (1)

Once again, normal street driving doesn't really see conditions where shock tower braces make much of a difference. Unless you're SuPer BaULiN around interstate on-ramps and such.


Modified by PatrickGSR94 at 7:44 AM 9/18/2008

johnlear

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PatrickGSR94 &raquo;</TD></TR><TR><TD CLASS="quote">Once again, normal street driving doesn't really see conditions where shock tower braces make much of a difference. Unless you're SuPer BaULiN around interstate on-ramps and such. </TD></TR></TABLE>

Patrick,
It depends on your definition of "normal street driving". My wife would never feel a difference from tower braces because her driving style is very sedate, and she just isn't switched on to handling nuances (I doubt she'd notice any handling change if I fitted say a much stiffer rear ARB, but would notice the stiffer ride). My driving style is a lot less sedate (without being anti-socially or dangerously fast), and I do feel a worthwhile difference with tower braces.

Also, some car chassis are be inherantly stiffer between the towers than others, so some cars will benefit more from tower braces than others will.