Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Go Back   Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum > General > Motorsports and Skilled Driving

Motorsports and Skilled Driving Discussion for Organized Racing and motorsports and tips and techniques at becoming a better driver.


Reply
 
Thread Tools Display Modes
Old 03-21-2003, 08:50 AM   #1
sykikchimp
WOW addicted
 
sykikchimp's Avatar
 
Join Date: Dec 2001
Location: the moon
Age: 42
Posts: 6,518
Trader Rating: (0)
sykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura about
Feedback Score: 0 reviews
Send a message via AIM to sykikchimp
Suspension Geometry...

Ok.. So I got All this fancy suspension stuff.. bars, and pillowballs, and adjustable arms OH MY!..

I've got is setup pretty well, this is what I got:
JIC FLT-A2's
JIC Adjustable RUCA
Pillowball Tension Rods
Moog Tie rod ends
Cusco Tension Rod
Do-luck Front ladder bar
Greg dupree subframe sapcers
OEM Sway bars
Cusco OS Front STB (CF)
Cusco Rear OS STB w/ Triangle Bar

I'm not sure how far the car has been lowered from stock.. I didn't take before and after measurements.

Alignment specs are:
Front:
-2 camber
0 toe
+8 caster

Rear:
-1 camber
.13 toe (this is more than likely from lowering the car with the OEM toe control rods
0 caster



My problem (which I have yet to fully diagnose) Seems to be that I am hitting the Rear bump stops on really tight slow corners. Like an Auto-x. Not hard, but it's there. Height of the car was adjusted with nothing but the strut mounting points, spring perch hieght has not been touched. At full droop the springs can be rotated on the perch with a little force.

It appears I have about 2" (maybe a touch more) suspension travel in the back, and probably 3-4 in the front.

I'm also having to run the front struts a good bit harder than the fronts.. out of 16 clicks front and rear.. they are at 11 front, 2 rear.


Any ideas on how to make the setup a little more balanced?
__________________
sykikchimp is offline   Reply With Quote
Sponsored Links
Old 03-21-2003, 09:46 AM   #2
uiuc240
Nissanaholic!
 
uiuc240's Avatar
 
Join Date: Apr 2002
Location: Naperville, IL
Age: 43
Posts: 2,093
Trader Rating: (0)
uiuc240 is an unknown quantity at this point
Feedback Score: 0 reviews
Send a message via AIM to uiuc240
How low is it?

Measure from the ground to the middle of the fender (top of arch) on all four corners. After that, I (or maybe someone with stock suspension) can measure for reference.

You might just have the thing too low to be effective.

Eric
__________________
2002 Mazda Protege5
1989 S13 w/SR20DET (sold)
uiuc240 is offline   Reply With Quote
Old 03-21-2003, 10:01 AM   #3
Dousan_PG
Post Whore!
 
Dousan_PG's Avatar
 
Join Date: May 2002
Location: Orange County, California
Age: 43
Posts: 16,640
Trader Rating: (23)
Dousan_PG is close to perfectionDousan_PG is close to perfectionDousan_PG is close to perfectionDousan_PG is close to perfectionDousan_PG is close to perfectionDousan_PG is close to perfectionDousan_PG is close to perfectionDousan_PG is close to perfectionDousan_PG is close to perfectionDousan_PG is close to perfectionDousan_PG is close to perfection
Feedback Score: 23 reviews
damn i typed a big reply and the computer took a crap. grr

ok um..
i have exactly the same setup (minus the moog) and i have never hit the bumpstops like you are. my car is lowered same too

my only thoughts
when you lower the car w/ the shock perch. you have to hold the spring perch to make sure it rotates at same the shock does. if not, the spring perch will be actally moving up when the shock is moving down. i did that once and the car's response was completely different.

that's all i can think of.
__________________
Aaron
Pink GodziRa
www.geocities.com/pink_godzira
Dousan_PG is offline   Reply With Quote
Old 03-21-2003, 10:37 AM   #4
sykikchimp
WOW addicted
 
sykikchimp's Avatar
 
Join Date: Dec 2001
Location: the moon
Age: 42
Posts: 6,518
Trader Rating: (0)
sykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura about
Feedback Score: 0 reviews
Send a message via AIM to sykikchimp
eric - I'll get that this afternoon..

dousan - I made sure not to do that.. If I had done that, then the spring would be preloaded, and I wouldn't be able to rotate the spring on the perch. I actually unbolt the bottom of the strut from the upright, and then adjust height, tighten it back down, then bolt it back to the upright.
__________________
sykikchimp is offline   Reply With Quote
Old 03-21-2003, 04:51 PM   #5
Halz
BANNED
 
Halz's Avatar
 
Join Date: Apr 2002
Location: bay area
Age: 39
Posts: 214
Trader Rating: (0)
Halz is an unknown quantity at this point
Feedback Score: 0 reviews
Here are some height measurements I took from a stock '93 base hatch

LF: 15.5" (39.37cm) from the center of the axle to the top of the wheel-well cutout 9" off the ground (flat spot just next to the side skirt )
RF: 16" (40.64cm) 8.5" off the ground
LR: 15" (38.1cm) 8.5" off the ground
RR: 15.25" (38.735cm) 8.5" off the ground

Measuring from the ground to the top of the wheel-well cutout doesn't take into account the profile of his tires.

..But in this case, with the issue being stroke, with the JIC, the height shouldn't really matter..

Is there a significant amount of 'strut' coming up through the rear camber plates?

How much can the rear wheel drop when you lift the rear of the car off the ground? And how far will the rear wheel move when the wheel is first placed on the ground, and then settles to ride height? Spring rates?

Is it possible that the rear inside tire is picking up off the ground in the turn?
Halz is offline   Reply With Quote
Old 03-22-2003, 10:15 AM   #6
logo20
Zilvia Junkie
 
Join Date: Apr 2002
Location: Houston, TX
Posts: 345
Trader Rating: (0)
logo20 is an unknown quantity at this point
Feedback Score: 0 reviews
my aligment is
front
-1 camber, .05 toe
rear
-2 camber, .07 toe

Is it dificult to adjust the alignment? I wish I had -2 up front and -1 in the rear.
logo20 is offline   Reply With Quote
Old 03-22-2003, 11:39 AM   #7
240racer
Zilvia Junkie
 
240racer's Avatar
 
Join Date: Nov 2001
Location: Minneapolis, MN
Age: 43
Posts: 574
Trader Rating: (0)
240racer is an unknown quantity at this point
Feedback Score: 0 reviews
how much travel is available from the JIC's? You said that you have 3-4" of travel in the front, does this mean that when you set the car down, there is 3-4" left in the travel? This would tell me that you have about 6" of total travel available. Is this the same for both front and rear? Do you know the exact amount of total travel available? If you have the same amount of travel available front and rear, then you should adjust the suspension so you have the same amount of sag on all four shocks. Sag is easily adjusted with preload, and that's why you have adjustable preload. Of course you can also adjust sag with spring rate, since a stiffer spring of the same extended length will sag less with the same amount of static load. If you are getting a lot more sag on the rear then the front, and you would like to reduce that, I would use the preload adjusters to do that. It is very hard for spring makers to make springs that are excatly the same length everytime, which is why adjustable spring perches are so nice, we can take into account the difference in free length with them. Also, your front springs are obviously different then your rear springs, so there is no reason I can think of that the spring perches (preload) should be adjusted to the same position.
__________________
Adam
'89 coupe KA24DE+T
14.1 @ 104 MPH

'88 Celica All-Trac turbo
stock, but no more ecu codes!!
240racer is offline   Reply With Quote
Old 03-22-2003, 11:41 AM   #8
240racer
Zilvia Junkie
 
240racer's Avatar
 
Join Date: Nov 2001
Location: Minneapolis, MN
Age: 43
Posts: 574
Trader Rating: (0)
240racer is an unknown quantity at this point
Feedback Score: 0 reviews
one more thing about the front damper adjustment, the rear springs ae softer then the fronts, is that enough to justify the difference in shock stiffness required??
__________________
Adam
'89 coupe KA24DE+T
14.1 @ 104 MPH

'88 Celica All-Trac turbo
stock, but no more ecu codes!!
240racer is offline   Reply With Quote
Old 03-22-2003, 10:21 PM   #9
sykikchimp
WOW addicted
 
sykikchimp's Avatar
 
Join Date: Dec 2001
Location: the moon
Age: 42
Posts: 6,518
Trader Rating: (0)
sykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura aboutsykikchimp has a spectacular aura about
Feedback Score: 0 reviews
Send a message via AIM to sykikchimp
Quote:
Originally posted by 240racer
one more thing about the front damper adjustment, the rear springs ae softer then the fronts, is that enough to justify the difference in shock stiffness required??
I think so.. They car is pretty loose with the rear springs they way they are. I think they car would be dorifto master with higher springs in the back.

Adjusting preload is what I was assuming I would have to do. I could raise the spring perches, and lower the mounting height so I gain stroke without increasing ride height.

I'm gonna put a ziptie on the back piston rod, and see if I really am hitting the bump stops.
__________________
sykikchimp is offline   Reply With Quote
Old 03-24-2003, 06:45 PM   #10
240racer
Zilvia Junkie
 
240racer's Avatar
 
Join Date: Nov 2001
Location: Minneapolis, MN
Age: 43
Posts: 574
Trader Rating: (0)
240racer is an unknown quantity at this point
Feedback Score: 0 reviews
sounds like a good idea, let me know how it goes.
__________________
Adam
'89 coupe KA24DE+T
14.1 @ 104 MPH

'88 Celica All-Trac turbo
stock, but no more ecu codes!!
240racer is offline   Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 11:13 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
vB.Sponsors
Copyright ? 1998 - 2022, Zilvia.net