rear end sways when hitting bumps? - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Garber · 01-11-2012, 03:54 PM

i cant tell if this im just getting more paranoid or what.

i installed kybs and lowering springs on my 96 s14 like a week ago. i dont know if i noticed it now because my suspension is stiffer or what but now when i hit bumps or variations in the road, the rear end kicks back and forth.
it seems like it is getting worse, but it could just be my imagination.

i jacked the back end up, and there is no play in the wheels or suspension. all the bolts appear to be tight. all of my rear bushings have been replaced with solid ones, so i doubt it is that.

is it possible my alignment got that bad that it would do this?

shiftdrift · 01-11-2012, 03:56 PM

do you have RUCA on the car and re-set the camber? sounds like your toe is out. that causes what you're saying and i've ran into it on cars before that are lowered.

Garber · 01-11-2012, 04:14 PM

stock rucas. i just didnt realize alignment could cause this.

my sister road in it today and said it felt like there was only one wheel in the back lol.

[email protected] · 01-11-2012, 04:23 PM

mine does it as well. im about 98% sure that its my blown rear shocks haha. are yours new or you bought them used?

Garber · 01-11-2012, 09:47 PM

i had them on my old car and they were awesome. they dont feel blown now

R3cK · 01-12-2012, 12:28 AM

had the same thing on my bmw, problem was the bad subframebushes. you still got the old one in?

shiftdrift · 01-12-2012, 09:52 AM

It's most likely alignment.

codyace · 01-13-2012, 04:55 PM

Quote:

Originally Posted by shiftdrift

do you have RUCA on the car and re-set the camber? sounds like your toe is out. that causes what you're saying and i've ran into it on cars before that are lowered.

Quote:

Originally Posted by shiftdrift

It's most likely alignment.

Winner Winner, chicken dinner!

Edwin562 · 01-12-2012, 10:08 AM

Most likely rears shocks are blown. Same thing happened to me before I changed to Coilovers. I had tokico blues with tein springs.

yetijeff · 01-12-2012, 01:33 PM

Lol I just posted a similar topic similar problem I do remember that when I initially installed my coilovers I also installed rucas and I had the same problem but all the time. I ended up installing all new adjustable arms in the rear and got an alignment and it fixed the problem

shiftdrift · 01-13-2012, 05:30 PM

Quote:

Originally Posted by codyace

Winner Winner, chicken dinner!

Send me it next day air!

Garber · 02-14-2012, 02:57 PM

alignment seems to have cleared it up 90%

codyace · 02-14-2012, 03:10 PM

What's the last 10%

Croustibat · 02-15-2012, 08:19 AM

The last 10% is caused by lowering, and there is no cheap cure.

These rear ends are made to toe in dynamically on compression and droop.

By lowering the car say 1", it means the car will toe OUT on droop for say 1/2" of suspension travel, and only then will toe in. Drop the car 3", and the suspension will never toe in on droop (which ricers dont care as they just dont have suspension travel because they fit rock hard springs)

It means the lower you go, the crappiest it will drive. BTW, what do you think your suspension does when braking ? Yup, you guessed it. Goes on droop.

You could counter that by adding more static toe in. But then there is tyre wear, and the car might be twitchy on acceleration and not flat roads.

There are only 2 solutions :
1/relocate toe arm pickup point on the knuckle or
2/relocate toe arm pickup on subframe.

Neither is easy.

There IS one known and working solution. Stock suspension height and suspension arm angles. If you want a lowered car that fit, you need sot keep suspension arm angles unchanged, so if you fit 2inch shorter coilovers, raise you subframe as much, basically. See the "roll center correction" thread for more info.

Nicelyphe · 02-15-2012, 08:37 AM

Buy coilovers = problem solved. Worked for me anyways! Car used to skip in the front and rear all over when I was running old stock struts.

Garber · 04-04-2012, 02:36 PM

i aligned the rear in my garage using string. the problem is gone but my steering wheel isnt straight anymore. oh well.

future · 04-04-2012, 03:35 PM

Mine was doing this before i pulled the engine. But im putting coils and s14--->s13 bushings in so hopefully itll stop

Garber · 04-07-2012, 09:19 AM

Quote:

Originally Posted by future

Mine was doing this before i pulled the engine. But im putting coils and s14--->s13 bushings in so hopefully itll stop

it was the rear toe in doing it

future · 04-07-2012, 09:41 AM

Nice. Good to know i just needed a alignment after i biught all these parts to fix it lol

zerodameaon · 04-09-2012, 11:41 PM

Sub frame bushings are shot. That does a lot more then people give credit to. Not saying the other reasons don't make up the majority but don't overlook those 4 attachment points. That's a $50 fix if you just get collars.

Garber · 04-10-2012, 03:08 PM

Quote:

Originally Posted by zerodameaon

Sub frame bushings are shot. That does a lot more then people give credit to. Not saying the other reasons don't make up the majority but don't overlook those 4 attachment points. That's a $50 fix if you just get collars.

no. it was the alignment.

Quote:

Originally Posted by shiftdrift

It's most likely alignment.

Quote:

Originally Posted by Garber

alignment seems to have cleared it up 90%

Quote:

Originally Posted by Garber

i aligned the rear in my garage using string. the problem is gone but my steering wheel isnt straight anymore. oh well.

Quote:

Originally Posted by Garber

it was the rear toe in doing it

zerodameaon · 04-12-2012, 12:01 AM

Like I said majority other reasons but the bushings do play a role in that sway.

01-11-2012, 03:54 PM	#1
Garber Zilvia Junkie Join Date: Mar 2010 Location: Lancaster PA Age: 32 Posts: 398 Trader Rating: (2) Feedback Score: 2 reviews	rear end sways when hitting bumps? i cant tell if this im just getting more paranoid or what. i installed kybs and lowering springs on my 96 s14 like a week ago. i dont know if i noticed it now because my suspension is stiffer or what but now when i hit bumps or variations in the road, the rear end kicks back and forth. it seems like it is getting worse, but it could just be my imagination. i jacked the back end up, and there is no play in the wheels or suspension. all the bolts appear to be tight. all of my rear bushings have been replaced with solid ones, so i doubt it is that. is it possible my alignment got that bad that it would do this?

01-11-2012, 03:56 PM	#2
shiftdrift Nissanaholic! Join Date: Nov 2009 Location: indiana Age: 31 Posts: 2,242 Trader Rating: (42) Feedback Score: 42 reviews	do you have RUCA on the car and re-set the camber? sounds like your toe is out. that causes what you're saying and i've ran into it on cars before that are lowered. __________________ SW Fab

01-12-2012, 09:52 AM	#7
shiftdrift Nissanaholic! Join Date: Nov 2009 Location: indiana Age: 31 Posts: 2,242 Trader Rating: (42) Feedback Score: 42 reviews	It's most likely alignment. __________________ SW Fab

02-14-2012, 03:10 PM	#13
codyace Post Whore! Join Date: Dec 2004 Location: Poconos, PA Age: 36 Posts: 8,030 Trader Rating: (58) Feedback Score: 58 reviews	What's the last 10% __________________ *Want Air Conditioning in your SR20 Swapped car? Check out www.sr20acbrackets.com for more information! Quest Alternator Conversions for SR20!* Check my Group Buy! Tired of lousy internal gates? Go external wastegate with one of my manifolds, Check out my group buy

04-04-2012, 02:36 PM	#16
Garber Zilvia Junkie Join Date: Mar 2010 Location: Lancaster PA Age: 32 Posts: 398 Trader Rating: (2) Feedback Score: 2 reviews	i aligned the rear in my garage using string. the problem is gone but my steering wheel isnt straight anymore. oh well. __________________ hardpark.net

01-11-2012, 04:14 PM	#3
Garber Zilvia Junkie Join Date: Mar 2010 Location: Lancaster PA Age: 32 Posts: 398 Trader Rating: (2) Feedback Score: 2 reviews	stock rucas. i just didnt realize alignment could cause this. my sister road in it today and said it felt like there was only one wheel in the back lol.

01-11-2012, 04:23 PM	#4
[email protected] Nissanaholic! Join Date: Jul 2008 Location: Zacatecas, Mx; Paramount, Ca Age: 31 Posts: 1,626 Trader Rating: (32) Feedback Score: 32 reviews	mine does it as well. im about 98% sure that its my blown rear shocks haha. are yours new or you bought them used?

01-11-2012, 09:47 PM	#5
Garber Zilvia Junkie Join Date: Mar 2010 Location: Lancaster PA Age: 32 Posts: 398 Trader Rating: (2) Feedback Score: 2 reviews	i had them on my old car and they were awesome. they dont feel blown now

01-12-2012, 12:28 AM	#6
R3cK Zilvia Member Join Date: Nov 2011 Location: bavaria Posts: 159 Trader Rating: (0) Feedback Score: 0 reviews	had the same thing on my bmw, problem was the bad subframebushes. you still got the old one in?

01-12-2012, 10:08 AM	#9
Edwin562 Post Whore! Join Date: Nov 2009 Location: Whittier (562) Age: 31 Posts: 4,721 Trader Rating: (35) Feedback Score: 35 reviews	Most likely rears shocks are blown. Same thing happened to me before I changed to Coilovers. I had tokico blues with tein springs.

01-12-2012, 01:33 PM	#10
yetijeff Zilvia Addict Join Date: Sep 2010 Location: Corona Ca Age: 31 Posts: 765 Trader Rating: (3) Feedback Score: 3 reviews	Lol I just posted a similar topic similar problem I do remember that when I initially installed my coilovers I also installed rucas and I had the same problem but all the time. I ended up installing all new adjustable arms in the rear and got an alignment and it fixed the problem

02-14-2012, 02:57 PM	#12
Garber Zilvia Junkie Join Date: Mar 2010 Location: Lancaster PA Age: 32 Posts: 398 Trader Rating: (2) Feedback Score: 2 reviews	alignment seems to have cleared it up 90%

02-15-2012, 08:19 AM	#14
Croustibat Nissanaholic! Join Date: Aug 2011 Location: France - Toulouse Age: 41 Posts: 1,851 Trader Rating: (0) Feedback Score: 0 reviews	The last 10% is caused by lowering, and there is no cheap cure. These rear ends are made to toe in dynamically on compression and droop. By lowering the car say 1", it means the car will toe OUT on droop for say 1/2" of suspension travel, and only then will toe in. Drop the car 3", and the suspension will never toe in on droop (which ricers dont care as they just dont have suspension travel because they fit rock hard springs) It means the lower you go, the crappiest it will drive. BTW, what do you think your suspension does when braking ? Yup, you guessed it. Goes on droop. You could counter that by adding more static toe in. But then there is tyre wear, and the car might be twitchy on acceleration and not flat roads. There are only 2 solutions : 1/relocate toe arm pickup point on the knuckle or 2/relocate toe arm pickup on subframe. Neither is easy. There IS one known and working solution. Stock suspension height and suspension arm angles. If you want a lowered car that fit, you need sot keep suspension arm angles unchanged, so if you fit 2inch shorter coilovers, raise you subframe as much, basically. See the "roll center correction" thread for more info.

02-15-2012, 08:37 AM	#15
Nicelyphe Zilvia Addict Join Date: Jan 2010 Location: PA Posts: 918 Trader Rating: (16) Feedback Score: 16 reviews	Buy coilovers = problem solved. Worked for me anyways! Car used to skip in the front and rear all over when I was running old stock struts.

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