coupe sport suspension on sedan
#31
09-23-2005 | 04:09 PM
#32
09-23-2005 | 06:01 PM
Originally Posted by Jeff92se
Questions:
If one runs the Z springs/shocks, does it affect the camber too much?
If one runs the Z springs/shocks, does it affect the camber too much?
If one is considering changing the springs/shocks/wheels in a G sedan anyway, is there any benefit in looking for a sedan with the sport package?
#34
09-26-2005 | 12:18 PM
Originally Posted by Jeff92se
Questions:
1. If one runs the Z springs/shocks, does it affect the camber too much?
If one is considering changing the springs/shocks/wheels in a G sedan anyway, is there any benefit in looking for a sedan with the sport package?
Thanks
1. If one runs the Z springs/shocks, does it affect the camber too much?
If one is considering changing the springs/shocks/wheels in a G sedan anyway, is there any benefit in looking for a sedan with the sport package?
Thanks
Oem max alignment specs you need to see
Front camber
Sedan -.83
Coupe -1.25
350Z -1.33
Rear camber
Sedan -1.08
Coupe -1.75
350Z -2.08
#35
09-26-2005 | 01:34 PM
Originally Posted by DaveB
$300 A-arms will fix front camber and $50 camber bolts and some drilling will get the rear camber close enough.
Not for the 03/04. The Sport package is wheels, springs, and struts. If you're looking at 05s, then yes because the Sport package includes an VLSD.
Not for the 03/04. The Sport package is wheels, springs, and struts. If you're looking at 05s, then yes because the Sport package includes an VLSD.
#36
09-26-2005 | 01:38 PM
Originally Posted by DaveB
I got my Coupe springs for $40 shipped and did the install myself. Like others have noted, I noticed better handling with my G on Coupe springs and Sport struts. I also find the ride to be better.
I've driven a G sedan with the 350Z set up and noticed the ride was choppy, very busy, and the suspension bottoms out on choppy surfaces. The reason I went with the Coupe springs is for the following reasons.
1) The Coupe springs are designed for a car with the same weight and basically the same weight distribution. The 350Z springs/struts are designed for a 200lb lighter car. It does make a difference.
2) Dropping a G sedan 1+" puts the camber out of spec. The front camber is not adjustable and the rear camber is only slightly adjustable. The only way to really put the front camber back into spec the right way is with $300+ camber arms. The 350Z springs make for some serious negative rear camber. Even the Coupe springs introduce more camber though the tires seem like they can handle it. The 350Z springs on the otherhand will require different camber bolts, along with some drilling, to get rear camber close to, but not completely into spec. Running more negative camber can improve lateral G's, but it will hurt straightline stability and on-center feel.
3) The G sedan's suspension geometry wasn't designed for a 1+" drop. Operating the suspension far outside of it's intended design can introduce nasty things like bump steer, snap oversteer, caster issues, dartyness, lack of feel on initial turn-in, etc.
4) The G sedan needs shortened struts to compensate for lost wheel travel. The 350Z struts are shortened, but they're very firm.
5) Though visually pleasing, lowering doesn't automatically mean better handling. Ask any suspension tuner and he'll preach this to you. You can typically lower a suspension .2-.6" and get some good results. Anymore than that and things start to get compromised for the reasons listed above. $3,000 coilover setups are great not because you can drop the car 2.5", but because you can adjust the suspension and tune the ride height and dampening. Most race tuners only do a .5" -.7" drop with coilovers. You don't see them doing 1.0-2.0 drops on true performance cars. Wheel travel means everything. If you really want to improve the handling of the G sedan, get swaybars, 17X8 light weight rims, ultra sticky rubber, and Koni Yellow struts and maybe Coupe springs.
Take a look at how much the factory tuners lower thier cars over the standard models. It's usually .25-.35" along with stiffer springs, firmer struts, wider rims, better rubber, and sometimes different roll bars at one or both ends.
I've driven a G sedan with the 350Z set up and noticed the ride was choppy, very busy, and the suspension bottoms out on choppy surfaces. The reason I went with the Coupe springs is for the following reasons.
1) The Coupe springs are designed for a car with the same weight and basically the same weight distribution. The 350Z springs/struts are designed for a 200lb lighter car. It does make a difference.
2) Dropping a G sedan 1+" puts the camber out of spec. The front camber is not adjustable and the rear camber is only slightly adjustable. The only way to really put the front camber back into spec the right way is with $300+ camber arms. The 350Z springs make for some serious negative rear camber. Even the Coupe springs introduce more camber though the tires seem like they can handle it. The 350Z springs on the otherhand will require different camber bolts, along with some drilling, to get rear camber close to, but not completely into spec. Running more negative camber can improve lateral G's, but it will hurt straightline stability and on-center feel.
3) The G sedan's suspension geometry wasn't designed for a 1+" drop. Operating the suspension far outside of it's intended design can introduce nasty things like bump steer, snap oversteer, caster issues, dartyness, lack of feel on initial turn-in, etc.
4) The G sedan needs shortened struts to compensate for lost wheel travel. The 350Z struts are shortened, but they're very firm.
5) Though visually pleasing, lowering doesn't automatically mean better handling. Ask any suspension tuner and he'll preach this to you. You can typically lower a suspension .2-.6" and get some good results. Anymore than that and things start to get compromised for the reasons listed above. $3,000 coilover setups are great not because you can drop the car 2.5", but because you can adjust the suspension and tune the ride height and dampening. Most race tuners only do a .5" -.7" drop with coilovers. You don't see them doing 1.0-2.0 drops on true performance cars. Wheel travel means everything. If you really want to improve the handling of the G sedan, get swaybars, 17X8 light weight rims, ultra sticky rubber, and Koni Yellow struts and maybe Coupe springs.
Take a look at how much the factory tuners lower thier cars over the standard models. It's usually .25-.35" along with stiffer springs, firmer struts, wider rims, better rubber, and sometimes different roll bars at one or both ends.
Their are two different oem 350Z suspesion's, unrevised Z suspension certainly do mean bounce and porposing issues. Revised oem Z suspension's are a totally different animal.
1. 350Z roadster's weigh the same as sedan's do and they have the same suspension as Z coupe's using the same revised setup.
2. Oem 350Z springs drop sedan's 1", the resulting alignment spec's while out of sedan specs are close enough to coupe specs so we can avoid the need to call out for aftermarket fixes least we get in the habbit to call out to all coupe owners that their oem specs will soon cause them undue tire wear, which is something we don't do to Z owner's which run even more aggressive alignment specs. Adding aftermarket alignment fixes on a oem Z drop is not called for on a oem Z suspension drop.
3. Suspension geometry is the same from Z to G coupe to G sedan, this is why alignment specs differ from sedan, coupe to Z in relationship to their ride heights. On the same subject line I would not drop a Z more then 1/2" or in otherwords drop a sedan more then 1.5". Sedan's that are properly setup from a watchfull eye on suspension specs, adjustable sway bar settings and carefull attention to what specs you set the alignment to BEFORE the car is pulled off the rack will dictate ultimate behavior at the handling limits.
5. Sensicle, but misapplied to sedan's since we share the same geometry as the Z which run's a 1" lower oem ride height to start with. And I'll point out that most 350Z tuning see's drop's greater then .2-.6", though this does not mean I agree with this. Nismo T2 SCCA springs drop the Z 1", Truechoice coilovers developed by the Unitech race team are recommended to be run with a .8-1" drop, Tein recommends to run the Flex coilover at a .9/.8" drop. In fact, coilovers that will let the sedan drop even just a 1" drop are not easy to come by, only way to get that is with full length adjustment.
From experience, Koni's at a 1" sedan drop only have 1.5" of bump travel in the front, even with 40% greater front spring rates that 1.5" of bump travel does not prevent kissing the bump stop's in the front on less them smooth corners, and that is with shorter oem 350Z bump stops that have been halved.
#37
09-26-2005 | 02:07 PM
Originally Posted by DaveB
Yes, the struts will die a quick death. Even the firmer Sport struts will die quick. The reason is the 350Z springs have a stiffer spring rate. Struts/shocks are dampners and are designed to dampen a particular spring rate. The 350Z springs will basically overwork the struts and kill them quickly. More importantly, the reduced height of the 350Z spring will put the G sedan struts far outside their intended operating range therefore killing the struts even quicker.
There is no way around this. A lowered ride almost always means a stiffer ride. The spring rates and dampening rates have to be higher to keep the car and suspension from bottoming out. Progressive rate springs like Eibachs offer a soft feel initially because their upper coil rates are softer, however when a fairly big bump is encountered, the spring compresses and the higher rate coils come into action and firms up the ride. This offers a decent compromise in real world driving, though most performance drivers prefer the consistent feel of linear rate springs.
There is no way around this. A lowered ride almost always means a stiffer ride. The spring rates and dampening rates have to be higher to keep the car and suspension from bottoming out. Progressive rate springs like Eibachs offer a soft feel initially because their upper coil rates are softer, however when a fairly big bump is encountered, the spring compresses and the higher rate coils come into action and firms up the ride. This offers a decent compromise in real world driving, though most performance drivers prefer the consistent feel of linear rate springs.
Eibach prokit's were developed on a non sport sedan's softer shocks, they were not aware that the sport suspension existed. Progressive springs compromise at the limit behavior especially if wide variation's in initial and peak rates are employed. Definately for those with comfort as a priority vs maintaining or enhancing the drive experience.
Once again oem spring rates as follows
2003-2005 G35 sedan with sport
314/342
2003-2005 oem sedan non sport
283/308
All G coupe production if delivered on oem 17's or 18's
314/342
All 2005 coupe's if delivered on oem 19's
314/427
2003-2004 350Z
314/342
2004+ 350Z
314/427
All 350Z roadster production
314/427
#38
09-26-2005 | 03:52 PM
Gsedan35-That's a very useful and interesting read. Much thanks. A couple questions though.
1) I've read lots of guys say that thier 350Z springs were causing inner tire wear issues and feathering on the fronts. The wider the tire, the more significant the problem. What's your take? Wouldn't adjustable A-arms fix this problem.
2) Nissan realized that alignment specs on the 350Z were to aggressive and caused quick wear and feathering. I'm uncertain of the fix, but I know some 350Z owners and even G coupe owners have had this problem. Sounds to me like a camber problem. How would Nissan fix this without A-arms?
3) You say the suspension geometry across the G and Z is the same therefore installing 350Z springs isn't a big deal. What about the G35X and it's .5 higher ride height? I find it hard to believe the same overall geometry can be applied to three different settings that have a range over 1.5". What about FX? It has the same suspension too.
I'm not trying to disagree with you at all. You've definitely done your homework and used the stuff on your own car. I would love to know that running the 350Z setup on my G wouldn't cause any problems.
Another question
As you know, I have the Coupe springs/Sport struts. The rear of my car with no load sits really low. I barely have a .5" gap between the tire and wheel well. The rear drop from the Coupe springs was .8". From the pictures I've seen, my Coupe springs ride as low in the back as the 350Z springs. Would I be able to get away with running just Z springs in the front?
#40
09-28-2005 | 01:37 PM
Originally Posted by DaveB
Gsedan35-That's a very useful and interesting read. Much thanks. A couple questions though.
1) I've read lots of guys say that thier 350Z springs were causing inner tire wear issues and feathering on the fronts. The wider the tire, the more significant the problem. What's your take? Wouldn't adjustable A-arms fix this problem.
2) Nissan realized that alignment specs on the 350Z were to aggressive and caused quick wear and feathering. I'm uncertain of the fix, but I know some 350Z owners and even G coupe owners have had this problem. Sounds to me like a camber problem. How would Nissan fix this without A-arms?
3) You say the suspension geometry across the G and Z is the same therefore installing 350Z springs isn't a big deal. What about the G35X and it's .5 higher ride height? I find it hard to believe the same overall geometry can be applied to three different settings that have a range over 1.5". What about FX? It has the same suspension too.
I'm not trying to disagree with you at all. You've definitely done your homework and used the stuff on your own car. I would love to know that running the 350Z setup on my G wouldn't cause any problems.
Another question
As you know, I have the Coupe springs/Sport struts. The rear of my car with no load sits really low. I barely have a .5" gap between the tire and wheel well. The rear drop from the Coupe springs was .8". From the pictures I've seen, my Coupe springs ride as low in the back as the 350Z springs. Would I be able to get away with running just Z springs in the front?3. Opps, forgot to exclude the AWD X. The X and FX use a different front suspension. All RWD G's and Z's have the same geometries, same hard points and suspension parts, they are enterchangeable. The coupe and Z of course pickup additional bracing that is not related to geometry.
Nothing to stop you from running oem Z springs in the front. The reverse is true as well, nothing would stop you from installing spacers over the rear upper spring seats, vary the thickness to gain the rear height gain you may want, up to 3/8". Energy makes 3/8" thick poly seat's you could use, going thinner will require some cutting and a dremel. I've used 3/32" spacers fashioned from sheet lexan, using 2 per side gave me a 3/16" gain.
#41
09-28-2005 | 01:44 PM
Originally Posted by aimco
Gsedan35-
I am thinking about installing Tokico D spec using the OEM springs in my 2003 G35 sedan. I am looking for a softer and more comfortable ride. What setting on the Tokico D spec do you recommend?
Thanks
I am thinking about installing Tokico D spec using the OEM springs in my 2003 G35 sedan. I am looking for a softer and more comfortable ride. What setting on the Tokico D spec do you recommend?
Thanks
#42
09-28-2005 | 02:55 PM
Joined: Jan 2004
Posts: 21,095
Likes: 47
From: Toronto, GTA north
Originally Posted by Gsedan35
I've heard stories that going too soft with D-specs makes the car feel underdampned. From first hand experience where I helped a member do a install, a sedan on oem coupe springs with the D-specs set to 4(might of been 5 turn's, hmmm) turn's off full soft made the car feel a small amount firmer then the oem sport suspension which is exactly that the owner wanted. In your case I would try 2 turn's off of full soft. Then give the drive the car about a week to test. The worst thing that will happen is having to pull the rear shocks off the car to turn them up on turn or so.
I found 4 turns to be close to OEM & is very comfortable.
JMO, but anything lower is just too underdampened.
I like a slightly firmer set up and normally run at 5 turns.
We're just headed out on a 2000 mile road trip,
I'll likely back off one turn to keep the co-pilot happy.
#45
09-28-2005 | 08:14 PM
Registered User
Joined: Nov 2003
Posts: 30
Likes: 0
Gsedan35
I've changed to the 350z springs about 2 month ago, and recently notice the feathering developing. Since this was my first time doing the work, needless to say I was very skeptic what kind of job I did. So here is my question regarding what you have say.
"1&2. Poor oem dampning (on 2003/2004 cars), wrong toe settings and the platform's high caster settings"
How do I remedy the toe setting and caster seting?
Second question, I think you or someone else have posted before the spring revision for 04.5 350z have the higher rear spring rate, what was the part number/model number to check on the spring to found out whether I have the stiff rear springs.
Thank you very much.
Peter
I've changed to the 350z springs about 2 month ago, and recently notice the feathering developing. Since this was my first time doing the work, needless to say I was very skeptic what kind of job I did. So here is my question regarding what you have say.
"1&2. Poor oem dampning (on 2003/2004 cars), wrong toe settings and the platform's high caster settings"
How do I remedy the toe setting and caster seting?
Second question, I think you or someone else have posted before the spring revision for 04.5 350z have the higher rear spring rate, what was the part number/model number to check on the spring to found out whether I have the stiff rear springs.
Thank you very much.
Peter