wolffttu

"mostly to keep the spring seated correctly (hence, spring mount) by a 1/4" to 1/2" is NOT going to make an effect on ride quality, WILL NOT change spring rates (due to no shift being made in static weight distribution, therefore no added/lost compression/extension on the springs)."

actually you will be shifting your corner weight distribution; changing ride height at any corner or corners will change the cross-weight percentage. no static weight will not change unless you have ballasts or start moving components (battery) etc. - not by much but the “weight distribution” at a stand still will be effected- good or bad ? Who knows, you would have to do some R and D to actually see the effects of corner weight distribution from cutting the spring mounts. but none the less you hit it 100% on the spot; the spring mount is to keep the spring seated CORRECTLY.

" What if no springs offered on the market lower the tail to the consumer's desired height, and they don’t want coilovers? How is it "hacking" the car? your shaving 1/2" off of a rubber mount "

no argument on that. if he wants to modify the car in an unsafe improper manner do it by all means. why not do it right and get some mounts custom made, instead of reducing the integrity of a rear spring mounts that are engineered to be a specific thickness and density.

“One of the most important aspects of racing is having a good handling balance. Setting static weight distribution and adjusting cross-weight percentage is one way to assure good handling. Taking the time and making the effort always pay dividends.” - grass roots motorsports

If you don’t care about handling or getting max performance from your car cut the mounts if you want it to ride better do some R and D and see what works best.

http://grassrootsmotorsports.com/art...orner-weights/ -

If you really want to get a good idea about springs, struts, ride height and effects to ride quality do more research before you cut the mounts; make an educated decision.

cheshirecat79

iTrader: (9)

Have you actually seen the rear spring mount on this car? Have you seen it cut? Have you seen how it actually mounts after the cut? Do you have any clue what you're talking about in relation to this car, this modification, or the point of the modification itself?

I'd hate to see how the car's handling is thrown all to hell if you have groceries in the back, or (god forbid) a passenger sitting next to you. NOOOOOOOOOO.

Again, this isn't a mod for people who care about corner balance. Those people will modify their suspension using proper parts. The points you are arguing are just ridiculous.

wolffttu

thankyou for proving my point further- i deal with race cars; i'm giving you a perspective from a racing standpoint. Enthusiasts may or may not care about corner balance. to the member who started this thread you got your answers if all you care about is looks go for it. if you want improved handling do it the right way.

cheshirecat79

iTrader: (9)

Yeah, I also sometimes forget that this website is based around an entry-level sports car made by Nissan.

wolffttu

there are plenty of nissan circuits out there using the 350z as a base platform.

Gsedan35

iTrader: (10)

For the right reason's and under the right circumstances, the spring mount mod is a great cost effective way to outsmart a aftermarket that still isn't up to speed for this platform. The most drop the mod will do, is .8" and that's when take the time to use a dremel with a sanding drum get covered with this awfull rubber powder that get's on everything within 6ft of where your working. Otherwise the typical drop is .5" or less.

So both you guys have points.

No we don't want to do the mod to drop more then 1.2"

In the here and now of this thread, this mod drops the rear only. I would not want to drop the rear only on a otherwise oem setup. No one has asked the op what year of Z he has. He's either on 342lbs rear springs or 427lbs. Take a look at the following master list of aftermarket springs for the Z, look at rear spring rate and rear drop amounts.

Eibach 350Z Pro-Kit progressive springs 1”/1”
Spring rates in LBS initial/final front 296/384 initial/final rear 316/421

Eibach 350Z sportline progressive springs 1.2"/1.2"
F: 239/400 R: 257/435

RSR 350Z linear springs .6”/.6”
Spring rates in LBS 345/417

Hotchkis 350Z Linear springs .6”/.8”
Spring rates in lbs 340/330

Cobb Tuning 350Z Linear springs .75"/.9" drop
Spring rates F345/R438


Tein S-tech 350Z springs .7“.6“ (fronts are slightly progressive, rears are linear)
Spring rates in LBS 386/402 (estimated front intial rate is 327lbs)

Tein H-tech 350z linear springs .3”/.2”
Spring rates in LBS 358/375

Progress Technology progressive springs 1.0”/1.0”
Spring rates in LBS 425/385 (final rates only, softer intial front progressive rate unknown)

Tokico D-spec 350Z shock & spring package DSK512 linear springs Drop 1"/1.5"
Spring rates in LBS 375/375

Tanabe GF210 Series 350Z progressive springs 1”/1.2”
Spring rates in LBS 336/375 (only peak rates are published, softer initial progressive rates unknown)

Tanabe NF210 Series 350Z progressive springs 1.2”/1.2” higher
Spring rates in LBS 314/353

Skunk2 350Z progressive springs 1.3”/1”
Spring rate in LBS 238/381 237/395

Swift 350Z linear springs .8”/.6” drop on 350Z, G35 drop will be higher)
Spring rates in LBS 336/364

Swift 350Z Spec-R progressive springs 1.2”/1”
Spring rates in LBS intial/final Front: 291/392 Rear: 280/448

Vogtland 350z progressive springs 1”/1”
Spring rates in LBS initial/final front 257/354 initial/final rear 285/422

Kg/mm springs 350Z DR21 super sport 15mm drop
Spring rates in lbs initial/final front 246/398 initial/final rear 252/409

Kg/mm DRacing progressive springs 1.2”/1.2”
Spring rates in LBS initial/final front 252/454 initial/final rear 252/482 rear

Whiteline 350Z linear springs (control)
Front: Part # 73219,
Spring rate 365 LBS Drop: .8"-1"
Rear: Part # 73220
Spring rate 445LBS Drop: 1"-1.2"
(sold as 2 front springs and 2 rear springs)
www.whiteline.com.au/store/


Espelir 350Z progressive springs 10mm drop F&R
386/515 (softer initial progressive rates are unknown))

H&R sport progressive springs 350Z 1.3”/1” drop
Spring rates in LBS 370/400 (peak rates only, softer initial rates are unknown)

cheshirecat79

iTrader: (9)

... and I'm sure they use the springmount mod, so this is very applicable to the discussion.

GeauxLadyZ

iTrader: (9)

Well said G, the exact point of the mod.

Exactly, the point at which you may start needing rear arms/toe bolts. The same would apply with springs/coils with a drop of 1.2" or lower. (Actually i think Nissan states .8" is the max, but thats been proven not always true in every case)

GeauxLadyZ

iTrader: (9)

Exactly, the only "adverse" effect, which even that hasnt been proven, but we must assume its true, as common sense tells us it would be.

Which it still would be seated correctly, even after the mod. Your shaving off the end that sits on the body, not the seat end of the mount.

Everything you said was ok until this paragraph. It is perfectly safe to do this mod, and why get some custom made!? They would make it exactly the same as it is after the mod. This in no way would reduce the integrity of the mount, but your welcome to try and prove me wrong. The mount will still be the same density, and still provide more than enough support for the spring.

For all you and i know, Nissan made the mount taller to increase the height of the rear ever so much in a quick, simple, and cost effective manner, without having to touch the springs.

Prob true, but still never proven. Therefore no reason to tout your opinion as being the end-all correct answer. Also take into account corner balancing is still effected just the same with a spring drop of equal length, what i have said from the beginning and am growing tired of repeating.

Thats the point here... we have done research.

Gsedan35

iTrader: (10)

I should have been clear, my thinking isn't alignment driven. It's bump stroke driven. Don't drop past 1.2" on oem based shocks that do not have shortened case and piston rod lengths. Tokico's D-spec shock and spring kit get's away with a 1.5" rear drop in spite of it's 375lbs rate because rear D-spec shocks for the Z fitment are shorter.

beezee

iTrader: (19)

I have an 05 Touring with stock suspension at 23,000 miles with 19" rims
(245/35/19 F and 275/35/19R). Just not happy with the fender gap in the rear. (about .5 higher in the rear). I have read about guys doing this mod together with spring drops to kind of even out. I guess coilovers are best but good ones are expensive. Thanks all you guys for your inputs.

GeauxLadyZ

iTrader: (9)

Ah, ok.

GeauxLadyZ

iTrader: (9)

[QUOTE=beezee;7758869]Its ok, you can still do it with stock, just dont take more than .5" off the mount.

guitman32

iTrader: (15)

His point in listing the spring rates and drops was that if you analyze the relationship between rear drop amount and rear spring rate, the lower the drop, the higher the rear rate.

Gsedan35

iTrader: (10)

You have 427lbs rear springs.

If your plus height in the rear according the factory service manuel, theirs no reason why you cannot do the rear spring mount mod to even out the height.

wolffttu

dampaning rate wont change b/c your not changing springs. just get an alignment after you mod your suspension

beezee

iTrader: (19)

Thanks guys for the technical info. Originally I thought I would have to do it with lowering springs. If it can be done on stock springs and shocks that is good news for me. My main aim is to even out the gaps.
And as cheshirecat79 has said, even though the 1/2" cut exposes a softer surface, that center plastic is more than strong to hold.