Not a thing, I completely agree with you. If any weight does shift one way or another, I believe it will be completely insignificant. Thats what Im trying to prove.

If thats the case, why does corner balancing make such an improvement ??

We aren't talking about corner balancing, we are talking about modifying static weight distribution.

Static weight and crossweight are two seperate measurments. To corner balance, you first get the static weight distribution where you want it, then you proceed with cornerbalancing.

Per the articles below: "The only way to change the static weight distribution percentages is to physically move weight around in the car. Jacking weight will not alter the left side or the rear percentages. "

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

http://books.google.com/books?id=BJU...num=5#PPA62,M1

EXACTLY!! This is basic physics, if even that. The only thing one would have to worry about when changing rake is applying increased pressure to the rear suspension components, but its no different than lowering the car with springs....just in the rear, though. If you have, per say, a camber kit, rear camber arms, toe bolts, etc. or a variation of these according to your drop, then everything is FINE.

There is no way doing this spring mod could change handling or weight distribution any more than getting springs or coilovers. If there are any changes, they would be insignificant.

i agree that any changes would be very hard to notice, but the roll couple is altered when the roll center is altered.

Quick question guys, does this springmount mod work for guys with true coilovers?

Thanks

When a car is up on corner scales and you lift the front or lower the rear you do add weight to the rear of the car, all you have to do is watch the scales. The other part about using you adjustable arms to chance caster, most people don't have arms that allow this. Most front arms only allow camber adjustment.

to the person asking about the spring mount mod when using true coilovers, just think about it. Would this work if your springs are no longer in this location.

His comment is a great example of how many people actually know what is going on , let alone what these mods actually do to the handling there cars.

I asked this question originally and to be honest after reading everything I am afraid to do it!!!

Honestly the cars sit pretty even from the factory when gassed up. There is no reason to do it.

But there is also no reason (proven anyway) not to do it. I would do it for a 1/4" BUT thats all i would cut. I try to stay away from doing "half-azzed" mods such as this. but to tell you truth i may do as the seat is easily replaceable, and very cheap.

My s-techs are great but could use a 1/4" butt drop.

I still think the spring mount mod affects the balance of the car somewhat but realized that my SLOPPY HANDLING was contributed by something other than the spring mount mod....I would like to apologize for this

just today i realised my problem on my car....I have had chitty handling for the past 40k miles and have thrown 3 sets of struts at my car as well as 4 sets of springs hotchkis sways and upper tubular A-arms with adjustable camber.....

EVERY time i thought i fixed my problem the sloppy handling came back.....

when i finally got hotchkis sways i thought my problems were gone, but all this did was put more pressure on the already blown bushings and work for a minute and then further damage the bushings until i was right back where i left off with sloppy handling once again....first i bought KYB struts which was a mistake cause they were weaker than factory....then i got tokico blues but they weren't up to the UNKNOWN task that they were compensating for bad bushings and a sway bar that was almost barely working cause of the bushings....enter the d-spec and it is drivable now.....but the bushings are so bad now that the one that connects to the chassis SEEMS to the eye to be fine but once you tear apart the suspension it has seperated......

To sum things up.

My lower control arm has 2 bad bushings.....the bushing that the strut attaches to is cracked on the bottom and sagging (WHY couldn't the nissan tech see that?????)

also the main bushing on the inner part of the lower control arm that connects to the chassis is separated and basically is in the same condition as a blown motor mount......but it is still in place.....i can literally twist the lower control arm left and right with little effort as if i was grabbing the end of a pipe and twisting it. The same exact problem on both sides of the car.

So HOW you may ask would this affect handling????? well the swaybar is connected directly to the lower control arm by an endlink, and the swaybar is NOT working because of this....and even if it is it is TOO LATE.....I need to replace these bushings in order to fix my problem.....

by the way...I pulled the d-specs and tested them and the are strong as hell on the stiffest setting.....i had them set to full stiff to overcompensate the front swaybar not operating correctly.....

this problem showed up at 50kmiles and now i have 100k miles....

if you have weird swaybar problems or are confusing it with struts being blown just remember that in order for the sways to work....the bushings on the lower control arms need to be in good condition or replaced with something better in order for the swaybars to work correctly...

I believe my rear control arm bushings are just fine...and i replaced my endlinks 9 months ago.....GLAD i don't have to purchase a full blown coil over kit now only to be disappointed.....

I just swapped back in my tanabe gf210 springs and had it aligned today and told the tech what happened just so that he knows....

i plan on getting whiteline linear springs and swapping them in since they lowered the Z EXACTLY the same as the tanabe's i have now.

WHEW!

i didn't read your novel, and maybe you thought of this. i would be willing to bet that your sloppy handling by doing the spring mount mod was caused by a rear toe change due to the rear ride height change.

in my experiences with these cars, rear toe plays a huge roll in response--moreso than i have noticed in other cars.

I had it aligned the next day after the spring mount mod.

guess your going to have to read my entire response before your post...sorry.

your post was full of incoherent rambling. did you fix your problem?

how was it related to cutting your springmount? what is your rear toe set at? please answer in an understandable/to the point response.

So how soon can we expect the results of your "Math". Even though the Z(like any other car) has its own design problems, a Nissan engineer would not take this long to do your math. Point is, they knew what they were doing when they worked on the design. And if you prove with your "math" that this is one of the design problems, that would be great.

danimaldaisy,
Good find on the lower control arm bushings. I also think you need to get some adjustable endlinks though. Unless you are running the settings that keep the stock endlinks perpendicular to the ground you will experience binding and odd behavior IMO.

What the hell are u talking about??

We were not discussing a "design problem" with the Z here, we were discussing the effects, if any, of doing the spring mount mod which is basically just cutting or shaving down the upper spring seat by 1/4 to 1/2 an inch.

This discussion has nothing to do with any "design flaw" from Nissan. This mod is purely cosmetic and we are studying the possible effects it may have on the overall handling/ride/weight distribution, etc.

Anyone had a shot of their car with this mod on stock suspensions?

The other thing I'd like to point out is that there are a number of members who switch to same size wheel/tire combos for track days instead of the factory staggered setup. Wouldn't this have the same theorized effect of transferring weight as cutting the rear spring mount?

YES , that will also do almost the same thing.