As posted on another forum sans spelling errors: So I drove a 09 civic for about a week and would like to get my 4 door (94 ex sentra) to match in feel (firm but not like riding on some 300# springs and was responsive). There are some size differences: 400lbs lighter, 10" shorter wheel base, different suspension geometry and arrangement, and 4" narrower (probably can make this up with some wider wheels). The stock honda anti sway bars are about the same as the SE-R bars, the spring rates are 170/200 whereas the XE are 112/92 (SE-R are 123/112), and the chassis on the civic is a bit more stiff. If I was to match the springs (via ground controls), anti sway bars, and get some csk's do you think I could get the same feel? I don't know the weight distribution but I am willing to be they are similar. Also thinking about using a bit of poly foam to make the chassis a bit more rigid with low weight penalty. Well after squishing a few numbers the spring rates would be, I think, 145/170 when taking in account for the 400lbs of car weight difference. I know the suspension is set up different (not coil over shock/strut design in the rear and not sure on the front) but I think if I get the basic's about the same as the civic it will be a comparable feel. The car is only a dd and will stay dd status, so only reason for wanting a setup change is for a more fun ride to and from work. Input is wanted and welcome, thanks!

You can't compare Honda and Nissan spring rates. They have different leverage ratios. You have a Nissan, its a B13. A stiffer frame will help a lot. The entire back half of the B13 is noodely. Honestly, you should not be looking at Honda's for your tuning starting points with Nissans. They are that different.

I want my B14 to be as comfy as my 65 Chyrsler Newport was,but it ain't gonna happen.You're comparing apples to oranges.Since 1994,your car has been busy flexing itself like an empty beer can,losing a huge amount of it's original rigidity.There are too many factors involved to even begin to approximate the ride of a brand new car,Civic or Sentra.I know where you're coming from,but it is what it is.

I didn't notice he wants it to feel like a 09. Sorry man. Thats just laugable.

When I say feel I am referring to the stiffness of the springs and responsiveness. I do understand that the leverage ratios are not the same but did not think that factor would effect my desired result so much. I also know there is almost no way I will make it feel like an 09; trying to make a 15yr old car feel like a brand new car is dumb and also, it is not my goal. To expand on the comment that I made: I liked the stiffness of the car (springs/shocks/antisway bars, chassis) and though it was appropriate for a daily driver that has a sporty ride; thus I would like my suspension to feel similarly. I was also not aware the b13's rear end is loose, and am now wondering what could be done to tighten it up. Probably a rear strut tower brace (4 point) that bolts into the trunk floor and some bolstering for the rear subframe/control arm bracket.

So has anybody ridden in a new civic? I did enjoy the ride and am aware my car will not feel like a new car (not my goal) but I would like the same firmness feel as the honda. Sooooooo could someone with experience recommend a spring rate that would be comparable in feel (referring to firmness only)? Thanks again!

Frame is flexing between the wheels and also in the trunk. It's just not that great a frame. Stiffness of springs is directly related to stiffness of the frame. You can't expect to have a similiar stiffness of one when the other is so different. Basically you want a sporty but not to stiff ride. BEST way to get that on a nissan is to not loose any suspension travel and to use Koni's. In the front you can start with a coilover setup and cut the perch off, weld a new perch on, get a 10 inch (or longer if you go with a soft spring) and start tuning. In the rear you need at least a 200 lb spring. It's been a while but I think you would be OK with a 225# is in the back. Might want to search some of my old post about B13's and Koni's or CSK.

I was planning on shoring up the chassis with a front and rear triangulated upper strut tower brace, lower contorl arm connectors, and filling the pillars and rocker panels with poly foam. I think that would adequately stiffen up the chassis so the suspension can do what is is supposed to do. I will also get the bonus of the car being faaaaaar more predictable. I don't plan on swapping up to poly bushings except for the anti sway bar mounts, everything else will get new rubber bushings if they are needed. Also I plan on going with csk's and welding the pearches on for ground control sleeves. Would a 200# spring in the rear (with something around 190# in the front I am assuming) make for a good dd suspension? I have no plans of bringing this thing on the track (may end up there even though I don't plan on it though :) I have read thru the suspension stuff alot and many questions have been answered already. I have been wondering about the shock travel though...do they only have 3" of travel when they are in the car or is it 3" hitting the top to bottoming out inside the shock? I am assuming it is the latter because if it was the former then somone would have made upper mounts that allow the shock to travel higher than intended by Nissan. Thanks again for all the help guys!

200 is a standard rear rate. 190 is way to soft in the front. Honestly, I think you have a bad plan. I would stick with stock spings and upgraded struts or go with some shortened Koni's and some Eibach Lowering springs and some Koni bump stops. Your plan is just not a good one unless you have lots of time and money to experiment. If you do then a Weld On front perch. Leave the rear hat on. Install GC sleeves. Figure out how soft you can go in the rear by getting the longest spring possible that does not coil bind in the back but is still soft enough. Then go about 50lbs heavier in the front.

Hmmmmmmm, what do you think about adding rigidity to the chassis? I also now propose to weld in a plate between the trunk and the passenger compartment. Thanks for the input on spring rates, I will probably folow your thumb rule. I am definately going to get the csk's and the gc sleeves.

I didn't notice he wants it to feel like a 09. Sorry man. Thats just laugable.
Respectfully I am not so sure about that sir. Depends on how far you take it.

Extreme Chassis Foaming:

http://www.sr20-forum.com/suspension/11917-foam-filling-chassis.html

Full '93 Classic Restoration:

http://www.sr20forum.com/members-rides/245943-93-classic-restoration.html

Upgraded Suspension:

1) B14 Wheels, 205/50/15 Fuzion ZR1 tires
2) Hyperco Gen II springs
3) KYB AGX struts
4) Koni Bumpstops
5) Progress rear sway bar (OEM front sway bar)
6) Bolt In Bars 3-point RSTB http://www.sr20-forum.com/group-buys/15248-group-buy-3-point-triangulated-rstb.html to replace the AT 2-point RSTB.
7) Cusco FSTB
8) Superpro caster bushings
9) Progress Lower Control Arm Brace - Thanks Brokeser!
10) Stephens Fender Braces: fender braces - SR20 Forum (http://www.sr20forum.com/group-buys/189747-fender-braces.html)
11) Foamseal the A-B-C pillars, roof perimeter channel, front rails, side rails. Which is covered in another thread here: http://www.sr20-forum.com/suspension/11917-foam-filling-chassis.html.
12) IKEA Brace welded in

That should make the vehicle about as stiff as possible without a cage, or seam welding the chassis. Which should quell NVH, and more importantly, by creating a super-stiff chassis, effectively force the suspension to do it's job. Which is why I include chassis bracing and stiffeners in with the suspension. Your chassis is effectively part of your suspension.

(Edited...snipped out non-related information.....)

Upgraded Interior, misc., etc...:

1) QuietCar (http://www.quietcoat.com/) sound deadener applied liberally to the doors, floorpan, wheel wells, back window shelf, entire trunk, and the IKEA braced panel behind the seats.
2) etc..etc...etc....
I followed in the footsteps of some really, really, suspension savvy guys. This dude named Mike Kojima and another guru named....Steve I think. ;)

They both foamed their cars. A "Z" and a S13 (S14?). Loved the results.

I merely followed their lead. With determination and a vengeance. Even took things farther than they had. Including Quietcar sound deadener, and every single bolt-or-weld-on brace available. Not to mention using both 8 lb foam (U.S. Composites) in the side rails, cross rail under the seats, and the front rails. I used 2 lb Handifoam in the A-B-C-pillars and the entire channel around the roof perimeter. See thread(s) above for extensive details, procedures, manufacturer links, product links, previous foaming articles and threads links, and one bazillion step-by-step pictures. :D

Recently a 3-point FSTB became commercially available. There's a link and full information on it in The Suspension Thread. Yeah, you guessed it. I'm going to buy one and replace my 2-point Cusco.

Because my chassis is not stiff enough. LOL.

I also know there is almost no way I will make it feel like an 09; trying to make a 15yr old car feel like a brand new car is dumb and also, it is not my goal.

I was also not aware the b13's rear end is loose, and am now wondering what could be done to tighten it up. Probably a rear strut tower brace (4 point) that bolts into the trunk floor and some bolstering for the rear subframe/control arm bracket.
Try this:

http://www.sr20-forum.com/suspension/11917-foam-filling-chassis.html

I'd put my chassis stiffness up against any 2009 compact vehicle. Any of them. I would LOVE to have my Classic rigidity tested right next to a brand new Nissan, Honda, or Toyota.

I was planning on shoring up the chassis with a front and rear triangulated upper strut tower brace, lower contorl arm connectors, and filling the pillars and rocker panels with poly foam. I think that would adequately stiffen up the chassis so the suspension can do what is is supposed to do. I will also get the bonus of the car being faaaaaar more predictable.
My Classic is *probably* the stiffest B13 chassis, sans in car bracing, on this forum. If not planet earth.

It is ridiculous, and over engineered. Every single trick in the The Suspension Thread. It is silent, no rattles, hums, or squeeks. It absorbs formerly car-and-teeth-rattling road imperfections with a muted thump. The chassis deflection is at about zero.

http://www.sr20-forum.com/suspension/11917-foam-filling-chassis.html

Hmmmmmmm, what do you think about adding rigidity to the chassis? I also now propose to weld in a plate between the trunk and the passenger compartment. Thanks for the input on spring rates, I will probably folow your thumb rule. I am definately going to get the csk's and the gc sleeves.
I know, for a fact, that you can decrease the NVH, and increase the rigidity of the B13 platform to modern standards, without a cage or roll bar.

It depends on how much money and time you want to spend, and how far you are willing to take things. I spent a bunch and took it to the extreme.

My car amazes me every time I drive it. It is light years more comfortable, composed, quiet, rattle and squeek free, and stuck to the pavement than it was before the restoration.

Yeah, I foamed my S13. It makes a nice difference. It made it better then my 2001 Passat in some ways. S13 had Swaybars, Koni's, Stock Springs, Heim Joints, etc. Nothing radical. I guess I have zero faith that a B13 is going to reach a 09 Civic level of ridgity and ride quality. To me the idea of chasing another cars feel is the wrong way to go. He is researching that cars spring rates and trying to duplicate them. It's just bass ackwards. A B13 is a B13. Can you make it better? Sure. You sound like you went all out and I have no doubt that your car feels great. But, using your car as a example he is on the wrong track. He needs to ignore the Honda spring rate idea and simply use what is known to work on the B13.

Edit: Even with my Foaming on the S13, I know it did not have the chassis ridgity of the Passat. I had foam and strut bars. It was better but it was not as good as my G35 (for example). Not by a long shot.

Thanks for all the info guys! I am thinking we can call this thread done now ;) So my final plans: get some steel and start fabbing up some bracing for the b13, get a lot of foam, weld in the ikea brace, csk's, try to get some seat time in another b13 with various spring rates to see what is reasonable and what is too far and pick something in the middle, and se-r anti sway bars with poly mounts and make some adjustable end llinks. And I will not be looking for 2009 rigidity but hope to keep up with a few :P Thanks again for all the input and help!

Yeah, I foamed my S13. It makes a nice difference. It made it better then my 2001 Passat in some ways. S13 had Swaybars, Koni's, Stock Springs, Heim Joints, etc. Nothing radical. I guess I have zero faith that a B13 is going to reach a 09 Civic level of ridgity and ride quality.
Rigidity, you may be right. I can say my B13 is a night and day difference vs. stock. It's not even in the same universe anymore. Is it as stiff as a 09 Civic? I don't know, however I am damn happy with my results.

The improvement is staggering. :)

To me the idea of chasing another cars feel is the wrong way to go.
Agreed. I wanted OEM-plus. A '93 SE-R that is better in every way than what I drove off the lot brand new. I was not trying to replicate the feel of anything else. A better, tighter, stiffer, less noisy '93 SE-R was my goal.

He is researching that cars spring rates and trying to duplicate them. It's just bass ackwards. A B13 is a B13. Can you make it better? Sure. You sound like you went all out and I have no doubt that your car feels great. But, using your car as a example he is on the wrong track. He needs to ignore the Honda spring rate idea and simply use what is known to work on the B13.
I never even attempted to discuss the spring rates issue. I figured folks with more expertise and knowledge would answer those questions.

Agreed on the Honda vs. Nissan spring rates. I read all kinds of "seemingly odd" spring rates on other platforms vs. what we use on B13/14's. They do not seem to correlate in the slightest.

Edit: Even with my Foaming on the S13, I know it did not have the chassis ridgity of the Passat. I had foam and strut bars. It was better but it was not as good as my G35 (for example). Not by a long shot.
I don't doubt you for a minute. However, I *think* I took things quite a bit farther than you or Mike. The over-zealous, committed, determined student, sir. ;)

"As good as a 2009 Civic"? I am not sure. Hard to determine. I have no idea how to test my results.

A vast, overwhelming, astonishing improvement over stock?

Absolutely. :biggthump

Shawn, I have no doubt your car is a HUGE improvement over stock. It sounds like he is on a better path now as well. He should read your threads. Great place to start.

Shawn, I have no doubt your car is a HUGE improvement over stock. It sounds like he is on a better path now as well. He should read your threads. Great place to start.
On that note, one more thread for Astroboy:

http://www.sr20forum.com/driveline-transmission/170794-b13-b14-b15-suspension-information.html

Astroboy, you may have missed the inside joke. 98sr20ve is the "Steve" to which I refer in a post above. He's one of the guys with real expertise that I was hoping would discuss spring rates with you. I quote Steve extensively in The Suspension Thread that I just linked for you.

I am a mere student of our suspensions. :tongue: