DC5 suspension...

[balleur]

I have an 04' RSX type S and was wondering what would be a good suspension set-up for daily driving and weekend road racing, im looking into getting a full coilover set-up and was considering gettin the function form set-up any input from drivers w/ experience will be greatly appreciated, thanks

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[Johnny Mac]

Originally Posted by balleur

I have an 04' RSX type S and was wondering what would be a good suspension set-up for daily driving and weekend road racing, im looking into getting a full coilover set-up and was considering gettin the function form set-up any input from drivers w/ experience will be greatly appreciated, thanks

I hate to tell you this, but the DC5 suspension (struts) isn't such a great design for racing. However, some teams (Real Time, King Motorsports, and a plethora of Grand Am teams) and some individuals have gotten the best from a flawed design by running lots of static front camber and higher spring rates and ARB rates in the rear to get the car to rotate on the track.

My advice to you is to call Scott Zellner at King Motorsports and ask him what he recommends.

[pos_cd5]

Originally Posted by Johnny Mac

I hate to tell you this, but the DC5 suspension (struts) isn't such a great design for racing. .

this is news to me. please elaborate.

[Targa250R]

So what "road racing" organization is this car competing with? What class?

Originally Posted by pos_cd5

this is news to me. please elaborate.

MacPherson struts are inherently bad for tarmac due to their awful camber curve. Honda took a bad design and made it even worse by attaching the steering arms up high on the strut on the RSX, which caused dynamic toe problems.

With that said, in a production car nothing is ideal, so you have to work around it. As mentioned, running a lot of static front camber and using extreme spring rates so that the suspension doesn't move much are the "solutions." Unfortunately, a car set up in this way does not lend itself very well to daily driving.

[mlrmotorsports]

Originally Posted by balleur

I have an 04' RSX type S and was wondering what would be a good suspension set-up for daily driving and weekend road racing, im looking into getting a full coilover set-up and was considering gettin the function form set-up any input from drivers w/ experience will be greatly appreciated, thanks

I agree call Scott he really knows his stuff! This is actually comon knowledge that is why most teams went to the TSX since it is a double wishbone vs. mcphearson (sp?)

[slammed_93_hatch]

Originally Posted by mlrmotorsports

This is actually comon knowledge that is why most teams went to the TSX since it is a double wishbone vs. mcphearson (sp?)

Not completely true, sure it was an added bonus but there are other reasons. The tsx will soon have a competitor for the top acura car.

If you have ever looked or dealt with a TSX then you know the rear suspension isn't without issues either.


I looked at one of the old davis cars this past weekend, and they were running exactly what davis had on the cars.

Front Springs looked to be 700 or 800 lbs couldn't really tell. In the rear they were running 4100 lbs springs with a speedway eng bar, i couldn't tell the thickness though.

[PIC Performance]

Originally Posted by slammed_93_hatch

In the rear they were running 4100 lbs springs with a speedway eng bar, i couldn't tell the thickness though.

that has got to be a typo......

[slammed_93_hatch]

Originally Posted by PIC Performance

that has got to be a typo......

Nope saw it clear as day Eibach ERS springs.

No one else believed me either, so they all went and looked.

5 inch 2.25 inch diameter and 4100lbs springs.

Real time got to just about those rates IIRC before they changed mounting points.

[PIC Performance]

hoooooly moooooly.

5" length and 4100lbs/in, how much travel did they have between each coil before binding??

[slammed_93_hatch]

Originally Posted by PIC Performance

hoooooly moooooly.

5" length and 4100lbs/in, how much travel did they have between each coil before binding??

I didn't touch the car cause no one was around just looked. And didn't have anything to messure. but i would say around .5 inch or so.

IMO the rear suspension with those rates, and that rear bar. There isn't much compression travel at the rear.

I had seen the RTR RSX's running 3200lbs 3 years ago i think.

Another RSX this past weekend was running springs between 3000 and 3500

[Targa250R]

Originally Posted by PIC Performance

that has got to be a typo......

Keep in mind that the motion ratio of the rear suspension on the early Global Compact Platform was really odd. It's nothing like the trailing-arm/wishbone/multilink rear we're used to seeing in Civics/Integras/etc. It's also an incredibly bad suspension design, so minimizing its movement as much as possible is ideal. Any suspension will work when you don't let it . . .

Spring rate alone doesn't tell you much. Wheel rate is a much more useful calculation.

[vinuneuro]

Is BMW's front suspension very different from this?

[Todd00]

Yep, most all of the competition RSX's run a rear springrate well over 2500lbs. Motion ratio is ~ 0.5:1, but if you allow the rear suspension to travel a great deal you'll get shock binding issues. So most folks just run them stiff as hell for those 2 reasons.

Also, camber is always near 0 in the rear. FWIW I believe the Spoon RSX (DC5 Integra) was running almost 6 degrees of static camber in the front.

But, if you are looking to make a decent HPDE car, get a good coilover setup that addresses a few of these issues (note: Megan is not a good coilover). Look for a front tierod attachment that has been altered to fix the angle, and look for rear shocks that have good quality poly bushings in them, because this is where the bind is.

For springrates, I'd start out with 500ft /1000rear with a big swaybar. You can daily drive this setup and it will be decent for an HPDE/autox. Key is keeping the rear spring twice that of the front. Race teams do it more than 4x the front.

For camber I'd do ~ 2.2 static front and .5 rear.

[Chris.]

Originally Posted by slammed_93_hatch

I looked at one of the old davis cars this past weekend, and they were running exactly what davis had on the cars.

davis acura? if so, thats where i bought my rsx from

btw when i was watching the race a couple weeks back on the speed channel, they said that the advantage to running the rsx as opposed to the tsx was its shorter wheel base.

[pos_cd5]

Originally Posted by Todd00

(note: Megan is not a good coilover). .

why?

[ruckus-kai]

any brands you would recommend? for a setup

[Too_Fast4u]

This might sound to some as newbie question, but just out of curiosity, is it possible to change from MacPherson struts to Double Wishbone on the DC5??

If so, what is required? Can anyone fill me in a bit more about the issue?

[1200 Hobos]

You'd have to re-engineer the design pretty much. Anything is possible I guess. I much rather start off with a better car istead of trying to re-design something unless you must have a DC5, then spend away. A DC2 has the double wish bone already and it's a lot lighter.

4100lb rear springs? Yikes, they pretty much bitch slapped that rear suspension and told it to stay where it is or else. That's not moving anywhere. Great thread btw, I had no idea those TSXs varied their front to rear spring rates by 4x as much! You also see the rear raised up quite high on those, yet another trick to get it to rotate.

Just to warn you, 1000lb rear springs are going to be quite a ride as a daily driver. I had 400lb and 500lb springs on the rear daily for awhile and those weren't comfortable at all. Nice on the track though.

[TunerN00b]

Originally Posted by 1200 Hobos

Just to warn you, 1000lb rear springs are going to be quite a ride as a daily driver. I had 400lb and 500lb springs on the rear daily for awhile and those weren't comfortable at all. Nice on the track though.

Keep the motion ratio in mind making such statements.

The MR of 0.5:1 makes that 1,000 lbs/in spring a 250 lbs/in wheel rate, which is only marginally stiffer than the 400 lbs/in rear spring (220 wheel rate) I run on my daily driven DC2.

250 lbs/in of wheel rate sound perfectly streetable to me.

This is why it is useless to just compare spring rates between different cars. We should compare the wheel rates between similarly weighted cars to get any meaningful comparison, as identical wheel rates with a large static weight difference mean radically different suspension natural frequencies...

[SiRCivic03]

This is quite a well informed thread. I had figured out the motion ratio/ spring rate issue for my suspension re-design on my EP3 from reading what was out there about realtime and the problems of the mac-strut front suspension front and bad motion ratio rear on the car. Ended up going 550lbs front and 1100 rear w/ revalved koni's, (-3.5 front camber, -.75 rear. Increased castor with swaped camber plates and offset bushings in DC5-R aluminum control arms) Again I'm not going to be a competitive car by any means just trying to have fun on the track and local autocross (after all i have a k20a3 so...yea not going anywhere fast)

For the couple of guys that asked questions about coilovers i would stay away from almost any prebuilt setup. That being said if you really don't have the need to go custom ground control/koni set up Buddy Club Racing Spec gets the ratios a little better then most for the DC5 with 10k/mm front 16k/mm rear but who knows the quality of the springs and shocks are a little suspect. Good luck.

[1200 Hobos]

Do you daily drive your EP set-up the way it is with the 1100ft/lb springs in the back? Is it bearable?

[6spdKEG]

in for info on this thread too. My 08 Civic si needs coilovers. Looking at custom ASTs or going with, dare I say, the underated Tein Monoflex which is an inverted strut front and can run up 12K front springs and 14K rears no problem. I would probably challenge them in the rear to run 16K though as the dude with the EP is stating above and run the given 10K springs front.

Currently running OEM suspension on drop springs with plenty of body roll with a 22mm RSBm 245 Dunlop star specs, -2.9 camber front and -2.6 rear (b/c of 245 tire clearance) OEM bushings everywhere.. . I do well, car turns in nicely but as usual for a FWD, it pushes at the limit. Placed 16th out of 97 drivers at my last AutoX in Arizona the other weekend. not bad for a car with no power mods or aft shocks and a driver with only 12 AutoXs and 8 HPDE days under his belt. Hopefully coilovers will allow me to be more smooth and I can move up the ranks even more.