Does anyone know if the height or spring rate (or any other aspect) of the stock springs on the 350Z have changed over the years? I've just been noticing that my 2004 Z (with stock springs) appears to ride a little higher than some newer Zs with stock springs. I may just be imagining it, though, so I wanted to check with all of you. I did some quick searching but couldn't turn much up on this subject.

 

i just put in megan coilovers last friday on my 2006 350 z with 900 miles

i have the factory front and rear suspension that came out and has only 900 miles on them

if you want them let me know

 

spring rates revised on '04.5 models.

 

Okay, thanks for the info. I have a 2004.5 model, so if what you're saying is true then I may as well just use those. I'm putting the stock springs back in since I'm tired of my car being so low. I like the handling of the RSR springs, but I just don't want any drop on this car. (It's pretty low as is from the factory.)

I was just wondering why it appeared that so many stock Zs look so low when I see them driving around. Perhaps the car runs a little lower while driving than when sitting parked? I could see that being the case on the freeway where wind resistance could push the car a bit lower, but around town it doesn't seem like height would be affected.

 

Differances are more complicated then just spring rates.

2004.5 brought about a running change known as the "revised" suspension. Changes include new shocks with a lot less compression dampning and more rebound control. While front spring rates remained unchanged at 314LBS rear spring rates were increased 25% from 342LBS to 427LBS. Front sway bar stiffeness was also increased 17% courtesty in thicker wall's the the bar's hollow construction with no increase in mean diameter. To the best of my knowledge rear bar strength has never changed. So how a 04 car rides differently from newer Z, has far more to do with the revised shocks then the rear spring rate and front bar change. These changes have not changed oem ride height, unless the FSM show's a change that I am not aware of.

 

Going from the 345lbs front RSR springs back to the oem 314lbs springs won't be a postive move, though I do understand your desire to raise the car up. Unfortunately, the aftermarket isn't geared towards offering any solution for those that want to keep their car's at oem ride heights, among spring manufactures. Some coilover option's do exist that can do oem ride height, though I would only consider those products that can do so with full height adjustment, getting to oem height with a lot of preload isn't a good idea. Thing is, not all full height adjustable coilovers are worth having.

 

That's been exactly my debate for quite some time now. I keep flopping back and forth as to whether I should keep the RSRs and just deal with scraping on things and other annoyances (such as not being able to use the parking garages in my town), or go back to the stock springs.

I currently have the Koni yellow shocks with my RSR springs, and I figure if I do go back to the stock springs I'd at least keep the Konis. I'd also keep my Hotchkis swaybars to give me a little adjustment. But like you said, I'm not a big fan of the stock spring rates. I'd almost be willing to pay the exorbitant prices for a set of nice adjustable coilovers if they could (properly) be run at stock ride height.

Bah... it's a frustrating position to be in. It's unfortunate that no good suspension manufacturers really take into account the utility of the car as a daily driver. It really is plenty low as it is (aside from the somewhat large rear wheel well gap), so some more aggressive spring rates at the stock ride height would seem to be a great upgrade for a lot of folks out there (like me) who can't really afford to lower this already low car.

And thanks for the detailed info on the 2004.5 revised suspension. I knew that the suspension had been updated, but I had never seen how exactly they changed it. My car was built in December 2003 and I purchased it in January 2004, so I *think* it's a 2004.5 model. I'm not terribly positive how I'd find out for sure, though...

 

I'm in the same dilemma, I want to improve handling but not lower the car any further than stock height if I can. Mine is an 03 touring.

I'm considering the RSR titanium springs for their relatively mild drop. (0.6" from what I read)

Any issues with RSR drop? 0.6" is pretty mild isn't it?

Cheers,
B

 

The RSR Ti2000 springs are exactly what I have. They are indeed one of the most conservative drops you'll get, but that .6" is actually still pretty low. If I have a passenger in the car with me, I have a hard time clearing most speed bumps. They do handle great, though, if you match them with the Koni shocks. That's why I'm so torn on swapping back to stock. At the track, I'd understeer with the stock suspension, but these RSRs are much more balanced. I'd hate to give that balance up, but I also dislike scraping so much.

To be fair, though, I think part of my scraping problem actually lies with my Crawford cats. They are angled downward a tiny bit more than the stock cats, so they make the y-pipe hang a tiny bit lower than it otherwise would. Under my car, about the only thing that ever scrapes is the y-pipe. So I guess if the y-pipe was back in the stock position, it would be slightly less of an issue.

 

I went with the Hotchkis TVS kit and love it. Springs are a conservitive drop as well.

Springs:
Front 9/16" (15mm) Drop
340 lbs/in
Stock 310lbs/in

Rear 3/4" (19mm) Drop
330 lbs/in
Stock 350 lbs/in

Sways:
Specs:
Front: 1 3/8" (35MM) Tubular(Bar Weight 13.5lbs)
4 Position Adjustable
Rear: 15/16"(24mm) Tubular(bar weight 5.5lbs)
3 Position Adjustable

Bar Rates:
Front:
Hole 1 = 1525 lbs/in (22% Stiffer than stock)
Hole 2 = 1845 lbs/in (48% Stiffer than stock)
Hole 3 = 2270 lbs/in (82% Stiffer than stock)
Hole 4 = 2855 lbs/in (129% Stiffer than stock)

Rear:
Hole 1 = 520 lbs/in (80% Stiffer than stock)
Hole 2 = 655 lbs/in (125% Stiffer than stock)
Hole 3 = 840 lbs/in (185% Stiffer than stock)

$399 from intense.

 

My only problem with the Hotchkis is that they made the rear springs *softer* than stock. That's definitely not something I'm after. The car understeers bad enough with the stock springs... I'm not quite sure I'd want the rear to be even softer. However, I really do like that the Hotchkis springs lower the back a tiny bit more than the front, though. I've seen a few Hotchkis installs, and they do level the car out. That's something I haven't seen any other spring do. From a purely cosmetic point of view, I like the Hotchkis springs the best for that reason.

 

Did you ever considered calling Tein and ordering custom springs?

 

Hi Jreiter,

With another passenger on board you have clearing isssues? I often drive with my wife so I'm always going to have an extra passenger!

I dont have the cats, so maybe I won't scrape like you do?

I suppose the alternative is a coilover which adjusts for height, but given that I don't track, might be an overkill. Better save the $$ for other mods.

Cheers,
B

 

The issue of softer rear springs isn't the real issue with your understeer, it's a sign of other issues that have nothing to do with the rear springs. Do a better job of making the front tires contact patches carry more load more evenly across the contact patch is much more important for reducing understeer.

 

Tein doesn't offer that service that I'm aware of. Eibach does, however, I'm not sure how it would work out in practical application. A better more viable option would be to purchase Tom Motorsport coilovers work out different springs for the kit.

 

I'm telling you... it's the fat passenger!

I do agree that the stock Zs are already pretty low. Maybe some of the Zs that you see have OEM like aftermarket side skirts that are closer to the ground?

 

Nah, they are totally stock, for sure. Seems like most Zs around my area are driven by older folks who probably don't have a lot of interest in modifications.

 

Thanks for the suggestion. The idea of evening out the load on the front contact patches does make logical sense, of course, but what are some ways one could do this? Camber adjustments? Swaybar adjustments?

I do run 255 mm tires in the front rather than 245, so that should help a little. I'd run 275s up front if they'd fit a little better, but it's such a close fit that I didn't really want to mess with it. (Not to mention the traction control system issues from the significant tire diameter change.)

However, I thought rear vs front spring rates *was* an important factor in over/understeer tuning. (?) If it's not the real issue on the 350Z, then why do most of the aftermarket suspension kits have significantly stiffer rear springs? (Or did I misunderstand your meaning?)