Which suspension best for Sedan: Si Coupe Suspension or HFP?

[mikeymike]

I have a 2006 DX-G sedan (5MT), and I found that the back end was really loose and the steering was imprecise. I have read that this is a common obsevation for the sedan. (Note that my other car is a Subaru Impreza, so I don't know if I've been spoiled by it).

What really disturbs me is that sometimes when I go over bumps, the back end kind-of bounces around; the back end will "skip" sideways about an inch when going over sewars (and some other bumps), sometime even when I am driving straight (this is really scary...). I remember that my old pickup truck did this as well.

So, in order to fix some of this uncontrolability, I swapped-out the stock sway bars with Si Sway Bars front and rear (taken from a Si coupe), using instructions from this forum (thanks guys). This really tightened up the handling, but the back end still "skips" sideways when going over sewars (and some other bumps). I'm not sure if it still does this because I have the stock soft rear shocks, or it is because I still have the stock 195/65/R15 Dunlop tires.

I think it may be the suspension, so I am thinking of upgrading it all. I would like to keep the same ride height (I live where there are a lot of rougher roads & potholes), but I am open to a modest drop and I would consider the 1inch drop of the HFP.

What would the best upgrade package for under $1000? I was thinking of the HFP upgrade or buying stock Si coupe struts/shocks/springs.

Thanks (and sorry for being so wordy).
-Mike

[taffysi]

I believe SI Ryan has his stock SI suspension for sale..and at a very very great price..I believe he's on this forum as well.. here's the link.. http://www.fgcoupe.com/forum/showthread.php?t=2077

[honda93]

Originally Posted by mikeymike

...but the back end still "skips" sideways when going over sewars (and some other bumps). I'm not sure if it still does this because I have the stock soft rear shocks, or it is because I still have the stock 195/65/R15 Dunlop tires.

-Mike

I'd say the 17mm Si rear bar is the culprit... Reinstall the 10mm bar that came with the car and also try an alignment where the rear tires are set with approximately 1/16" ~ 1/8" total toe-in. This should dial enough tail-happiness out to make the car more stable.

Anthony "Mario" Crea
NNJR-SCCA

[mikeymike]

Originally Posted by honda93

I'd say the 17mm Si rear bar is the culprit... Reinstall the 10mm bar that came with the car and also try an alignment where the rear tires are set with approximately 1/16" ~ 1/8" total toe-in. This should dial enough tail-happiness out to make the car more stable.

I also happen to have LX Coupe (10,000 miles) and HFP (new) rear shocks available for sale for nothing more than shipping to your location... They are stiffer without being overly stiff and would recompensate for the removal of the bigger 17mm Si rear bar, yet won't add to the skittering over harsh roads because they absorb impacts and control spring oscillations, unlike a sway bar which is a wierd looking spring, thus adding spring rate to that end of the car...

Let me know about the shocks and if you decide to make other changes.

scca8@yahoo.com

NOTE: Edited because I realized he has a Sedan, not a Coupe!

Anthony "Mario" Crea
NNJR-SCCA

It seemed that the problem was worse before I put on the larger Si rear sway bar, but if anything, it is probably the same. I am a little hesitant to remove the Si rear sway bar because it really tightened up the back end on normal roads and decreased the floatyness on the highway.

I'm just wondering about if the stock shocks just cannot handle the increased spring rate of the Si sway bar. Another question, would the HFP shocks (which are 1" shorter than stock), still work properly with the stock springs?

Your thoughts?

[honda93]

Originally Posted by mikeymike

I'm just wondering about if the stock shocks just cannot handle the increased spring rate of the Si sway bar. Another question, would the HFP shocks (which are 1" shorter than stock), still work properly with the stock springs?

Your thoughts?

1. If there is ANY shock on the market that cannot handle a sway bar increase, it should be pulled from use and redesigned. Sway bars simply do NOT add that much spring rate to overpower a shock.

2. The HFP SPRINGS are 1" shorter. NOT THE SHOCKS!... I've got them and the OEM LX Coupe rear shocks side-by-side on a shelf in my garage. No physical difference, just the internal valving is different.

Ultimately, it should be noted that ALL the new Civics have been bestowed with stiffer shocks and springs throughout the range for 2006+ compared with any previous Civic generations (relatively speaking, of course). Many people on this board complain about that, at which point I remind them that Kia and Hyundai still set their cars up soft for the subcompact segment.

Anthony "Mario" Crea
NNJR-SCCA

[mikeymike]

Hi All,

I have decided to go with a full Si suspension on my sedan. Another member has sold me their used Si suspension, so I'll install it when it arrives in two weeks.
So, what I'll end up with is a DX-G sedan with Si coupe struts, shocks, springs, and front/rear sway bars (the whole shebang!).

I'll let you all know my impressions (installation, handling, etc).

Until then,
-Mike

[Garrison]

I would like to know how it handles as well. I think I am headed the same route.

[mikeymike]

I finally got down to installing the Si coupe suspension on my DX-G sedan (along with the Si sway bars that I did before). I haven't done the alignment yet (I have an appointment tomorrow).

So far the car feels much more solid, planted and playful. A bit bumpier at slow speeds, but hey, If I wanted sloppy and mushy, I would've bought a Corolla. The car is much more controlled and better handling, especially at higher speeds.

I've got winter tires on now but the handling is still 100x better than the stock suspension and stock 3-season tires. I can't wait until I put my 17" rims/summer tires in April/May.

I'll give a bit more feedback when the roads in Ottawa clear up (we've had a bit of snow and ice the past couple of days), and when the alignment is done tomorrow. I plan to keep the alignment at the spec in the owner manual (at least for now).

Cheers,
-Mike

[Sleepy]

So the SI suspension will fit the lower models? (I have an EX coupe) I am thinking of exchanging out the EX suspension up to the SI set up and wasn't sure if all the parts will fit into my EX.

Any input would be great...

[fa1]

Yep all suspension fits between all 8th gens.

[mikeymike]

Originally Posted by Sleepy

So the SI suspension will fit the lower models? (I have an EX coupe) I am thinking of exchanging out the EX suspension up to the SI set up and wasn't sure if all the parts will fit into my EX.

Any input would be great...

All parts fit pertfectly into all sedan and coupes, and install without too much trouble. The only thing that I would highly recommend is that if you are doing it yourself, get a spring compressor for the rear springs (or spend hours monkeying around compressing them with a hydraulic jack like I did...)

The other thing is that you will need an alignment job after doing this. After I put in the new suspension, the alignment was out by quite a bit. The alignment might have been out by a little bit before the installation, but after it was out by a lot.

Good luck, and enjoy a much stiffer ride!

[Sleepy]

Originally Posted by mikeymike

All parts fit pertfectly into all sedan and coupes, and install without too much trouble. The only thing that I would highly recommend is that if you are doing it yourself, get a spring compressor for the rear springs (or spend hours monkeying around compressing them with a hydraulic jack like I did...)

The other thing is that you will need an alignment job after doing this. After I put in the new suspension, the alignment was out by quite a bit. The alignment might have been out by a little bit before the installation, but after it was out by a lot.

Good luck, and enjoy a much stiffer ride!

thanks for the info, I have a buddy who will be installing them, I just needed to know if the exchange was doable.

[samuel02]

Hi Mikeymike ... I own a Civic EX Sedan 2006 and i am experiencing the same problem as you ... Bouncing rear end left to right on bump and beleive me it is really SCARY ... Will have the shock change at the dealer .. my car is brand new ...

[mikeymike]

Originally Posted by samuel02

Hi Mikeymike ... I own a Civic EX Sedan 2006 and i am experiencing the same problem as you ... Bouncing rear end left to right on bump and beleive me it is really SCARY ... Will have the shock change at the dealer .. my car is brand new ...

You'll have to let us know how that goes. I suspect that the wimpy rear shocks are to blame. I wasn't sure if my original shocks were defective or they are just not good enough (by design). I swapped the entire suspension, so I guess I'll never know...

-Mike

[samuel02]

Guy's ....

Now we are talking ... never felt better ... just got back from the Honda dealer and they change my back left Shock. Now the car is handling like it never did ... Wow what a damage Shock can do ... Now it's really going good and strait over bumps like it never did.... Happy new Year and have a nice day

[No. 7]

Originally Posted by fa1

Yep all suspension fits between all 8th gens.

hey buddy, could you advice if the Si 2 Dr HFP suspension could fit JDM civic 2L (155bhp)? Or is there a HFP suspension for Si 4Dr. I am from Singapore and strangely there is not a single HFP suspension being offer by the dealer here. would like to order it from the states. Thanks.

[gibbletz]

Originally Posted by No. 7

hey buddy, could you advice if the Si 2 Dr HFP suspension could fit JDM civic 2L (155bhp)? Or is there a HFP suspension for Si 4Dr. I am from Singapore and strangely there is not a single HFP suspension being offer by the dealer here. would like to order it from the states. Thanks.

You guys get the Type-R.