DC2R Handling Improvement

[Saget]

Hey Guys just looking for some advice. I am looking at improving the handling of a DC2R which is stock suspension wise. Can any one tell me is there any value in upgrading the following parts:

1. Cusco - Strut Brace - Type Ti (Front and Rear)
2. Cusco - Sway Bars (Front and Rear)
3. Cusco - Lower Arm Bar - Version I (Front & Rear)
4. Carbing - Rear Tie Bar

Do Luck - Rear Cross Bar (Is the same as rear sway?)

Taken from Nengun.com

As this car is a daily driver to and from work over some ordinary roads I am reluctant to install coilovers as I have read on this forum and heard from others they are can be extremely hard/stiff, skip over bumps/potholes and generally uncomfortable to live with. More suitable for weekend and track.cars.

[EKVTIR-T]

If your happy with the stock suspension then just leave it.
Try strut bar's,rear sway and some good tyre's or upgrade to 16inch wheel's.
You should feel the difference.

[bennjamin]

none of the above mods will improve your cars handling.

Look at perhaps some nice coilovers or good spring/shock combo that will lower your cars centre of gravity and stiffen it up abit.
Then get some good road tyres then a full front n rear alignment :)

[JohnL]

none of the above mods will improve your cars handling.

You're suggesting that upgraded ARBs wont improve handling?

You're suggesting that tower braces wont improve handling?

I suggest you are wrong on both counts.

[m0nty ITR]

1. Cusco - Strut Brace - Type Ti (Front and Rear)
2. Cusco - Sway Bars (Front and Rear)


Do Luck - Rear Cross Bar (Is the same as rear sway?)



Forget bolted strut braces. If you can afford it choose a welded item like a Carbing or 5Zigen.

The rear cross bar is a bar that ties the rear of the car to the rear struts diagonally. It increases structural rigidity in the rear of the car and will induce a little more oversteer than you'd be accustomed too.

I'll get Chi to post pics because he has albums of em. :p

[EK Civic R]

Not all coilovers are give a really harsh ride, but there are a few brands around that are made for street use.
They lower the car, give you better handling and so forth...
But which ever kit you get it will be stiffer than stock..

Not sure what the tein ss are like, but D2 and Spoon coilovers seem to be quite soft, much smoother than tein flex by far

[55EXX]

the rear sway bar will lean the cars roll resistance balance towards oversteer and decrease body roll. that would be my first point of call. oversteer is alot more fun and alive. then a good wheel and tyre combo. 16's with some wide, hard side wall, sticky rubber. then go the braces.

what are you afraid of? lowering it? or making it hard ride? to me street setup suspension is big sway bars and softer spring/shock combos. that way you still have a smooth ride without the associated bad body roll. my old ek had kings and kyb shocks, smooth as, whiteline 24mm front 22mm rear sways and the ride was smooth, had no bodyroll and handled exceptionally well. sways add a almost progressive spring rate to your car. one can move up or down slightly fine for potholes etc big ones anyone feels so dont hit them. but its when the cars body is rolling when one wheel drop and the other side goes up. 2 opposite directions. this is where the sway holds them together.

[JohnL]

Forget bolted strut braces. If you can afford it choose a welded item like a Carbing or 5Zigen.


Monty,
Did you not read my reply to your similar statement in another thread? In case you missed it I'll paste it below. If you did read it, do you disagree? If so can you please explain why you disagree?

=======

Tower braces only work in compression and tension, they don't and can't stiffen the chassis in any vertical manner (beyond to the most insignificant degree). They simply don't have the beam strength or tri-angulation required to contribute any significant vertical stiffness at the towers, to do so they would need to be substantial 'girders' or tri-angulated structures, and none of them are.

Imagine that you place one end of the tower brace tube securely in a vice, then lean on the other end, what will happen? The bar will flex along it's length, more so the closer to the end held in the vice. If we assume any significant vertical chassis flexure at the towers as a result of bump loading or weight transfer, then the forces involved will be far greater than the force we can apply to the bar when we 'lean' on it. A tower brace can't resist such a force.

Imagine the front of the chassis to be like this, l___l, with the lower cross member being the 'cross member', and each vertical member being the unbraced towers. If we place another member across the top (tower brace) then we make the structure a rectangle and brace one tower to the other tower (in compression and tension) which makes the towers more laterally rigid than without the brace, but it's still not going to resist vertical loadings very well because a vertical loading will cause the rectangle to become a parallelogram. No tower brace is going to be vertically rigid enough to resist the rectangle becoming a paralleogram under vertical load, unless it had a similar sort of beam strength as the existing lower cross member, which no tower braces are even remotely close to.

A single bolt attachment looks as if it's an 'articulation', but in reality it isn't since the forces don't act in a manner that will cause it to articulate, or rather, they will but some slight articulation at this point is unavoidable whether the bolt acts like a hinge or the bar flexes. If the bolt is properly tight then the bar will flex slightly in any case.

It makes no significant difference whether or not the bar itself is welded or bolted to the brackets that attach to the tower tops, nor whether the bar attaches to each bracket with one or two bolts. It is important that the bar tube itself be rigid in compression and tension (compressive rigidity requiring significantly large OD and / or wall thickness in the tube), and that the brackets that attach the tube itself to the towers be robust and very rigid.

It is also important that the tube be absolutely straight, any bends seriously compromise both the compressive and tensile rigidity of the tube. If a bend is unavoidable in order to clear components, then the bar OD and wall stiffness needs to be substantially greater than with a straight tube. There are a number of braces that have bends in the bar, but the OD of the bar isn't great enough to minimise compressive and tensile flexure in the bar.

There are a number of tower braces on the market that have rather fimsy attachment brackets, they are made from material that is too thin and otherwise not well designed to carry loads from the bar through the bracket without the bracket flexing. If the brackets flex then it doesn't matter how rigid the bar is, the tower brace as a whole is only as good as it's least rigid components. The brackets should be made from steel plate at least 4mm thick, and designed (i.e. braced) to transfer loads from the tube into as much of the bracket's 'base plate' as possible, not just to a localised area in the base plate.

Bracing to the firewall is a good thing, but won't make up for the main tube or brackets being too flexible. If the entire tower brace isn't rigid enough then it won't have much affect on chassis stiffness and thus on handling. I suspect this is why there are a lot of people who have fitted tower braces but claim they do little to nothing for handling, i.e. they have flimsy braces not rigid braces. My home made tower braces are very rigid (in compression and tension, and in the brackets), and they definitely do make a significant difference.

[JohnL]

the rear sway bar will lean the cars roll resistance balance towards oversteer and decrease body roll. that would be my first point of call. oversteer is alot more fun and alive. then a good wheel and tyre combo. 16's with some wide, hard side wall, sticky rubber. then go the braces. to me street setup suspension is big sway bars and softer spring/shock combos. that way you still have a smooth ride without the associated bad body roll. my old ek had kings and kyb shocks, smooth as, whiteline 24mm front 22mm rear sways and the ride was smooth, had no bodyroll and handled exceptionally well.

I'd mostly agree with 55EXX, his approach to setting up a road car suspension is very sensible, as are his ideas on appropriate tyres. I think I'd place a bit more emphasis on the importance of somewhat higher damper rates, and to somewhat higher spring rates, but it does depend on the spring rates fitted as stock (at least some Hondas have very soft stock springs, e.g. the CB7 Accord). A lot of cars have overly soft dampers because stiffer dampers can create more harshness than stiffer springs (all else being equal).

For improved road handling etc, some cars really could do with a reasonable spring rate increase, others tend to suffer from the dampers being too soft, and many from both springs and dampers being too soft. Nearly all cars could do with better quality dampers such as Koni or Bilstein, whether this be a relatively softer damper like the Koni 'red' (still stiffer than most stock dampers) or a stiffer damper like the Koni 'yellow'.

The stock dampers on most cars are not all that good, regardless of rate. It's not all about raw damper stiffness (some stiffer dampers aren't all that good), but about stiffness in different conditions, such as when controlling body roll or when resisting large inputs created by larger bumps (both these conditions require different damper characteristics in these different conditions, and good dampers can accomodate both, less good dampers won't do this as well).


sways add a almost progressive spring rate to your car. one can move up or down slightly fine for potholes etc big ones anyone feels so dont hit them.

An ARB doesn't provide a 'progressive' rate, but does modify the 'spring rate' in some conditions but not in others. At a single wheel in bump or rebound, a stiffer ARB adds it's stiffness to that of the coil spring, so the single wheel rate is increased when one wheel hits say a pothole. In double wheel bump or rebound (say hitting a dip / bump that spans the full road width) the ARB has no affect on rate at either wheel.


but its when the cars body is rolling when one wheel drop and the other side goes up. 2 opposite directions. this is where the sway holds them together.

The ARB doesn't "hold them together". It adds stiffness to the spring rate when in roll, thus increasing roll stiffness to the end of the car at which it's fitted. Increasing roll stiffness at one end of the car increases weight transfer at that end of the car while simultaneously reducing weight transfer by an equal amount at the other end of the car (despite nothing having been done to that end of the car). If you fit say a stiffer rear ARB you increase rear weight transfer and decrease front weight transfer, thus decreasing understeer, possibly to the point of having oversteer.

The beauty of ARBs is that they increase roll stiffness (as fitting stiffer springs would do), but allow the use of softer springs, which tends to allow the wheel to better follow the road contours for better grip on less than perfectly smooth surfaces.

[Saget]

Thanks alot for the explanation and feedback!

The Cusco sway bars are listed as 164% front and 151% rear. Seeing as the DC2R's stock sway bars are 24mm front and 22mm rear the end result would be:

39mm front
33mm rear

Would this be too extreme for street use?

There are M&M, Mugen, Spoon, Carbing, Cusco, Whiteline Tower/Strut bars, how do i know how much if any improvement these offer, in stiffness, over the stock front strut bar and which would be the best rear strut bar to get?

So is there no value with the Cusco lower arm bar and carbing rear tie bar?

[fatboyz39]

For street and semi track, LEAVE YOUR stock swaybars. There big enough.

I would brace up the whole car and make it stiffer. You already got front stock chassis brace, add a strut brace if allows. Front lower bar is a good mod. Rear strut bar, c pillar bar. Then after go for some nice coilovers, i would recommend tein flex. damper and height adjustable, with top pillow tops.

Then after a FULL bush kit, i.e change your old bushing to some new harder ones. Noltec/energy and etc sells these. Then after front and rear camber kits.

[55EXX]

At a single wheel in bump or rebound, a stiffer ARB adds it's stiffness to that of the coil spring, so the single wheel rate is increased when one wheel hits say a pothole. In double wheel bump or rebound (say hitting a dip / bump that spans the full road width) the ARB has no affect on rate at either wheel.
thanks thats what i wanted to say. that the wheels over uniform bumps is still smooth. yeah the progressive rate thing was a crap way of putting it.


The ARB doesn't "hold them together". It adds stiffness to the spring rate when in roll, thus increasing roll stiffness to the end of the car at which it's fitted
my way of terming roll resistance in layman terms. the bar want to hold the wheels in the same position vertically so when one goes up the other wants to too etc when they want to go other directions the bar adds spring rate to the outside wheel and takes it from the inside so in laymans terms stops the inside dropping and the rear going up therefore in laymans term holds them together.

john L i have in the suspension thread a Q about spring/shock matching and i ask what is the advantage of stiffer springs if i have adjustable dampers sways etc.

[G_Vtec]

i find that the stock sway bars are strong enough for the DC2R.

I would recommend adjustable shocks & springs combos, front & rear camber kit, rear strut and new bushes front and back. These options will improve the car's handling dramatically. At least it did very well for me :)

[55EXX]

how big is the dc2r sways

[beeza]

22 or 23mm I'm pretty sure.Can someone verify :)

[fatboyz39]

rears are 22mm. Fronts are 24mm

[T-onedc2]

DC2R AUDM Sways
Front - 24mm
Rear - 22mm

I agree completely with JohnL on everything, he's spot on.

I have ITR setup on my DC2 and I gotta say after putting the Spoon rear strut brace on ride quality and rear predictability has improved markedly.

[SHIFTY]

for my car (which is basicly a dedicated track car now) i have done several things on the handling side of things..

front fender braces (j's racing)
Buddy club race spec coilovers
Rigid Rear Strut Brace (made by carbing)
C-piller bar (j's racing)

i am yet 2 replace the front strut brace but i will soon with a 3 point one which looks like it will stiffen up the front nicely...

also i have stripped the rear of my car and it only weights 1170kg with me in it and a full tank of fuel, and im around 70kg :P)

Cheers Dave

[JohnL]

The Cusco sway bars are listed as 164% front and 151% rear. Seeing as the DC2R's stock sway bars are 24mm front and 22mm rear the end result would be:
39mm front
33mm rear
Would this be too extreme for street use?

A 22mm rear bar is pretty substantial already, I wouldn’t think you need (or really want) to fit a stiffer one for road use. A 33mm rear ARB would be massively stiff. To give you some idea of how bar OD affects rate, the stock rear ARB on CB7 Accords is 14mm, a 17mm bar is approximately 2X as stiff as stock, a 19mm bar is 2.7X as stiff as stock, a 33mm bar will be… well I’d have to crunch the numbers, but it’s going to be mega stiff compared to stock (these numbers only pertain to a change in bar OD with no other change in the physical shape of the ARB, which does have an affect on rate).

Of course if the Cusco rear ARB is a hollow (as opposed to solid) bar, then the stiffness increase over the stock 22mm bar would be less than suggested by the numbers above for the solid Accord ARBs above, but it’s still going to be a mighty stiff ARB. Looking at the Cusco listed stiffness increase over stock rates, I’d lay strong odds on their rear ARB being a hollow unit, if it were a solid bar there would be no way it could only be 150% stiffer than stock.

If you want to reduce understeer, then increasing the front ARB rate more than the rear ARB rate will have the opposite affect, i.e. increase understeer. A stiffer front ARB will also reduce roll more, and the steering / handling is likely to be more responsive, but the roll stiffness balance will favour increased steady state understeer, and increased directional stability.

If you were fit both the Cusco front and rear ARBs, then according to their listed front / rear stiffness increases over stock, you would be getting more front roll stiffness increase than rear roll stiffness increase, which theoretically will worsen understeer, but improve steering response.

I suspect that with such a stiff Cusco rear ARB, that for road use the car would become directionally unstable and subject to oversteer in corners, so Cusco make their front ARB even stiffer to re-introduce some understeer for directional stability etc. If I’m correct then to me it suggests the rear ARB is actually too stiff. Perhaps Cusco is trying (for marketing reasons?) to have the biggest available bars on the market simply due to the common perception that ‘bigger is better’, but then trying to keep the handling balance reasonably safe for less than expert drivers??? I’m just speculating.


There are M&M, Mugen, Spoon, Carbing, Cusco, Whiteline Tower/Strut bars, how do i know how much if any improvement these offer, in stiffness, over the stock front strut bar and which would be the best rear strut bar to get?
So is there no value with the Cusco lower arm bar and carbing rear tie bar?

I'd be surprised if the stock Type R front tower brace were not OK (if Honda bothers to design one for the Type R, I’m reasonably sure it would be properly engineered), but I've never actually seen one (got a pic?). A rear tower brace is definitely a good thing to fit if it doesn't already have one, especially if it's a hatch type body which tend to be even less rigid in the rear body than sedans.

I don't know the Cusco 'lower arm bar', or their 'rear tie bar', but if the 'tie bar' triangulates the rear strut towers to a more rigid part of the chassis then it would be good, as long as it does this properly. Pics would help.

[55EXX]

DC2R AUDM Sways
Front - 24mm
Rear - 22mm

they are plenty big enough!

[SHIFTY]

i got a rigid rear strut tower brace.. is stiffer then the any other one as it is one piece (have 2 eather remove side panels or cut them 2 let the strut fit.. it is a tight fit 2 get on, which can only means its stiff :P

http://i142.photobucket.com/albums/r95/DCR_88/rearrr.jpg

[beeza]

Awesome man! Got a closer shot at all?

[SHIFTY]

http://img253.imageshack.us/img253/1971/cimg0835tq4.jpg

there ya go mate

[55EXX]

would be good to weld some bars onto that to make it a triangulated stucture with the c pillar bar

[beeza]

Very Nice! ^^ and that is a great idea!
I have seen a couple of bars in that position bent which can only mean it's needed.