DCFryARGHHH

i'm about to pick up a 05 dc5 type-s, and i've been reading a bit about the suspension setup, and how it's not the best design by honda. if anything, some people has said it's the worst by honda.

i've had a 95 civic before, pretty basic suspension setup while keeping it a daily driven street car
-koni yellows
-ground control 450f/500r
-asr subframe brace
-22mm itr rear sway
-itr 5 lug brakes
-hawk hp+ pads up front
-oem pads in the rear
-kragen rotors all around
-stainless steel brake lines
-roll cage, miracle x-bar, front strut bar

i've driven on the track a couple times, not for all out racing, but more for the driving experience and competitive driving, HPDE's only

with the DC5, i understand the front is the macpherson style with the tie rod connected straight to the shock, when you lower the car past a certain point, the tie rod angle is so extreme, you lose the steering feel and handling just goes out the window. the only solution is to get aftermarket coilovers that have the tie rod mounting point lower than factory, to compensate for it.

as for the rear, the stroke of the shock is so short, i've seen some companies using 3200-4000lb spring rates in the rear!! my question is, why is the spring rate in the rear so much higher, it's almost 4x higher than the fronts in all situations

TunerN00b

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DCFryARGHHH &raquo;</TD></TR><TR><TD CLASS="quote">as for the rear, the stroke of the shock is so short, i've seen some companies using 3200-4000lb spring rates in the rear!! my question is, why is the spring rate in the rear so much higher, it's almost 4x higher than the fronts in all situations</TD></TR></TABLE>

Motion ratio.

If you ran identical rate springs front and rear in the DC5, you'd have a significantly stiffer front than rear. Not sure on exact numbers (maybe someone else can post them), but the rear motion ratio is significantly worse than the front.

Thats why you can't compare spring rates between chassis. The spring rate is meaningless. The rate at the tire, which takes the motion ratio into account, is what actually matters.

Stinkycheezmonky

To answer your question very simply, you CANNOT have a competitive suspension on a DC5 that's at all streetable. Because of those ridiculously high rates needed, it'll handle and feel like crap on the street.

DCFryARGHHH

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stinkycheezmonky &raquo;</TD></TR><TR><TD CLASS="quote">To answer your question very simply, you CANNOT have a competitive suspension on a DC5 that's at all streetable. Because of those ridiculously high rates needed, it'll handle and feel like crap on the street.</TD></TR></TABLE>

thats what i'm thinking, i was thinking of running spring rates in the rear 2x or 2.5x more than the front, so i could get the car to rotate a little better, as far as on the street, i'm pretty used to stiff suspension

Stinkycheezmonky

1. You don't need rotation on the street.
2. You might be used to "stiff" suspension, but seriously, "race" or "competitive" suspension is not fun on the street. In addition to all the not-fun you'll be having, you'll also be blowing out shocks. Hooray.

NTCustoms

agree with what was said above. also, inverted tie rod ends and tie rod brackets have been used to correct the steering arm angle.

Rtype16

Motion ratio of the front suspension is .947

Motion ratio of the rear suspension is .605

So say you want to run a 600lbs spring in the front on the RSX I have seen from 600-1000 in the front. The rear spring for the 600lbs would be around 1800lbs. and this doenst even take into account the unsprung weight.

But dont ask me about the RSX as I know nothing

Todd00

Don't forget the other problems:

front: lowered too much = bad roll center

rear: shock/bushing binding

Stinkycheezmonky

Gee, really makes you wonder why ANYONE in their right mind would want to start with one of these?

NTCustoms

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stinkycheezmonky &raquo;</TD></TR><TR><TD CLASS="quote">Gee, really makes you wonder why ANYONE in their right mind would want to start with one of these? </TD></TR></TABLE>

heyyyy....

Lo-Buck EF

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stinkycheezmonky &raquo;</TD></TR><TR><TD CLASS="quote">Gee, really makes you wonder why ANYONE in their right mind would want to start with one of these? </TD></TR></TABLE>
ignorance is bliss

JamesL

As stated above, it is virtually impossible(or unfeasible) to have a competitive roadracing suspension setup on this chassis, while maintaining any hint of streetability.

That being said, it doesn't sound like the threadstarter needs a competitive setup. If you want to continue to do HPDEs and track days with your car, you can still have tons of fun. And you can have plenty of leeway in tuning your suspension for increased performance.

This chassis is not the easiest to tune. But it can be setup to be much easier to drive and much more competitive than many make it out to be... But there are things that need fixing, unlike previous generations.

Most of the main points have been covered, but I will reiterate some I feel are of great importance:

* Steering arm angle. Get this as close to parallel with the ground as you can. Inverted tie rod ends can be used. A fellow over on clubrsx.com has designed a steering arm bracket that raises the mounting point of the inner rod as well. I can tell you first hand it is a very nice piece.

* Front caster angle. The more you can get, the better. Look into Kmac camber/caster plates, and consider a set of caster-offset spherical bearings for the front LCAs(Special Project Motorsports). Or if your pockets are deep, Tracy Sports/M&M Honda make LCAs with the spherical bearings already pressed in. I have heard numbers such as 7-11mm of increased offset. What that translates into in degrees of positive caster, I do not know. But expect to pay around $1500 for a pair.

* Revalved rear shock absorbers. Koni makes great units... but with the spring rate needed in the rear, they are simply not up to the task.

* Stiff rear swaybar. What is the best unit? It is beyond me. NTCustoms and I were just chatting today about a friend he knows who has found many of the aftermarket swaybars for the DC5 to be almost erroneous in design. How much truth there is in this statement I do not know.

* Front roll center. Due to the different design of the front and rear suspesion on this chassis, lowering the car evenly will unevenly bias the front and rear roll centers. J's Racing makes a nice looking unit, an offset ball joint which raises the position of the front steering hub in relation to front LCA, theoretically correcting the roll center to a more appropriate level. What is the correct level? I have no clue, and I doubt there are many who do. I have not actually used the J's piece... and the location of the vehicle's roll center (and the corresponding correction required, if any) will almost certainly differ from vehicle to vehicle, depending on setup. The J's Roll Center Adjuster is more of a "best guess" correction. But from what Ive heard and read, it is better than nothing.

* Front camber angle. More negative camber! As much as you can get! Well... not really... But with the Mcpherson strut front, the dynamic camber gain via compression of the suspension is almost negligible. And the amount of negative camber attainable is limited... Even when using adjustable camber plates. There are ways around this, such as using 1 or 2 eccentric crash bolts in the strut housing to illicit more camber. Or swapping the front LCAs for the DC5R units. But regardless, you will need a good deal... especially if you are running R-compound tires. Shoot for being able to attain at least 3 degress of negative camber. This should allow you some room for tuning your setup to your liking.

* Weight Reduction. This can be said for any car. The lighter it is, the faster you are going to go. But the DC5 is heavy for a Honda. Especially one marketed as a "sporty" car. It weighs in the 2700s stock, which is almost a travesty. The K20 and nicely geared 6speed make up for some of this... but the handling and braking performance suffer. If you can trim a few hundred pounds off the car, great! If you can trim 500 lbs off the car, fantastic!. The last time I had my car (an EM2, same chassis, different body) on the scales, it came in at 2500. It will be getting realigned and cornerweighted next week, and should be around 2400. Not bad, but hardly competition worthy. If you are serious about weight reduction, here are some things to consider:

* Ditch the stock seats for some(or 1) aftermarket fixed back seat. Most weight in around 15-20 lbs... vs the 60 lb stockers.
* Replace the roof skin with one from a lower model without a sunroof. I am not sure as to the availability of the sunroof on the DC5 chassis, but I believe the Canadian Base level DC5 comes without one. The DC5R also. You could fabricate a sunroof plug if that suits you, but I imagine youd shell out just as much.
* Carbon fiber trunk/hood. Not the most weight savings, but they are worth some. And they remove weight on the top of the vehicle, exactly where you don't want it.
* Interior panels/pieces. Remove what you don't need. If you can live without sound deadening, remove that too. Ditch the passenger side airbag, and consider an aftermarket steering wheel. Also consider the potential danger in streeting a car like this.
* Remove AC if the climate you are in warrants it. I live in Texas, so that is a definite no go.
* Reduce as much rotational and unsprung weight as you can.


* Driver modification. Hey... this one always needs work. The DC5 might not be the pinnacle of Honda's engineering, but it is far from a lemon. It fits within most "weekend warriors" needs... and then some. Don't get your hopes dashed because the car won't be able to keep up with an 2000lb EK hatch with a Kswap around the track. That is just the nature of the business. If you are actually looking to competitively campaign a car, you should look elsewhere.

... that being said, in regards to driving the car, I have found that it loves anything and everything you can do to rotate the rear. This means learning how to effectively trailbrake into corners, how to left foot brake in situations that require weight transfer off the rear, how to breathe the throttle to allow the rear some room to move, etc... It means spending some quality time with your car, going to driving schools, going to track days/HPDEs, and actually learning the ins and outs of it. Being able to effectively and quickly pilot any car requires time... the DC5 just requires a bit more.

Todd00

I agree with everything that you said, except for the DC5 being heavy. ~2700lbs, in stock form, is definitely lightweight (anymore) for a Honda/Acura. The 94-01 GSR was 2667, so the DC5 added less than 50 lbs.

Not a bad tradeoff for a K-series motor.

The DC5 can easily be around 2500lbs while keeping most creature comforts (I have the weights in the RSX FAQ). If a car is a daily driver, it's just silly to compromise with removing interior panels and such.

Stinkycheezmonky

This whole damn thread is silly.

JamesL

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stinkycheezmonky &raquo;</TD></TR><TR><TD CLASS="quote">This whole damn thread is silly. </TD></TR></TABLE>

At least the threadstarter asked a somewhat intelligible question.

We aren't debating how to "slam his ride"... but the DC5 chassis does have features/shortcomings that make tuning it a bit different from other Hondas.

Stinkycheezmonky

I'm sure he (and others with RSXs) appreciates your help, but HE was the one with the desire for a "streetable competitive suspension". To me, that makes it silly from Post 1. I don't understand why people think such a thing exists. You're absolutely right that he DOES NOT need that, but it's what he was asking for.

SkankyEJ7

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stinkycheezmonky &raquo;</TD></TR><TR><TD CLASS="quote">Gee, really makes you wonder why ANYONE in their right mind would want to start with one of these? </TD></TR></TABLE>




<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JamesL &raquo;</TD></TR><TR><TD CLASS="quote">As stated above, it is virtually impossible(or unfeasible) to have a competitive roadracing suspension setup on this chassis, while maintaining any hint of streetability.
</TD></TR></TABLE>

Wasn't Realtime racing running like 4000lbs spring in the rear, from what I've seen in different setup you need at least double the springrate in the rear as compared to the front.

JameSL did a made a very good post.
ALso JameSL do you which swaybar he was refering too?

JamesL

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stinkycheezmonky &raquo;</TD></TR><TR><TD CLASS="quote">I'm sure he (and others with RSXs) appreciates your help, but HE was the one with the desire for a "streetable competitive suspension". To me, that makes it silly from Post 1. I don't understand why people think such a thing exists. You're absolutely right that he DOES NOT need that, but it's what he was asking for.</TD></TR></TABLE>

I follow you.

I believe most people have this image in the back of their heads of them being able to tear up the track on the weekends, but still drive their car on the street when need be. That is why I was hoping to point out to the threadstarter that a suspension setup geared towards making the car suitable for track days/HPDEs/etc is probably exactly what he is looking for... not the elusive "streetable, but race winning, competition" setup. Because, you are right, they simply don't exist.

JamesL

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SkankyEJ7 &raquo;</TD></TR><TR><TD CLASS="quote">
Wasn't Realtime racing running like 4000lbs spring in the rear, from what I've seen in different setup you need at least double the springrate in the rear as compared to the front.

JameSL did a made a very good post.
ALso JameSL do you which swaybar he was refering too?</TD></TR></TABLE>

I do not know the specifics of RealTime's setup, but it wouldn't surprise me

In regards to swaybars, we specifically discussed the Comptech bar and the ASR 32mm hollow bar. But, as I mentioned above, I do not know how much truth there are in these claims. Both of those companies are fairly well renowned. Makes you wonder... what company does make a good swaybar for the DC5?

Stinkycheezmonky

I know the Realtime cars have been through some pretty extensive development over the years, and the ridiculously high rates in the rear are no longer being used (to my knowledge). However, that did require some kind of re-engineering of either the suspension itself or their approach to how the rear suspension behaves.

Todd00

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Stinkycheezmonky &raquo;</TD></TR><TR><TD CLASS="quote">I know the Realtime cars have been through some pretty extensive development over the years, and the ridiculously high rates in the rear are no longer being used (to my knowledge). However, that did require some kind of re-engineering of either the suspension itself or their approach to how the rear suspension behaves.</TD></TR></TABLE>

Originally the Realtime cars did run ~4000lb rear springs when using the stock rear geometry/pickup points. You really want a 1:4 ratio. A 1:2 ratio is 'tolerable' if you want to build an autox car/daily driver. This is why I like the Tein S-Tech springs for a daily driver. They are ~250lbs front and ~500lbs rear.

In the last year when Comptech 're-engineered' the rear suspension, they stepped back to more moderate rates like they ran on the DC2's.

And to answer the original question...it is very difficult to build a track car for a daily driver that you can live with. The DC5/EP3/EM2 makes this even more complicated due to the suspension layout.