Has anyone swapped out their Q stock springs? I'm thinking I'd like to find something that will be 3/4" - 1" lower, somewhat stiffer but not harsh.
Seems I recall someone saying alignment is negatively impacted with any change in ride height.
Springs for the Q
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Mayhem_J30
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Q45tech
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- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Nope the Eibachs will lower the front about an inch and the rear 0.8" .....the negative camber will go 0.8 degrees more negative all around .....the rear might have enough to get back to the -1.0 degree spec.
Severe inside tire wear will be the result.....only the Michelin Pilots can survive for long with the resultant neagtive 1.5 degree front and they must be flipped every 8-10k to equalize.
Other than the look, lowering will only provide a 1-2% improvement since the new lowered CG is only 3-4% lower times the correction factor of the track width.
I have lived with a set for the last 52,000 miles.
The front/rear springs must be secured [top and bottom] with tie wraps as on a severe rebound they will rattle in the perch.I am think of going back to stock when the current shocks wear out by Xmas [rear 60k].......yes the tokicios and oem [front 40k] last about half as long with the lowered springs!
Severe inside tire wear will be the result.....only the Michelin Pilots can survive for long with the resultant neagtive 1.5 degree front and they must be flipped every 8-10k to equalize.
Other than the look, lowering will only provide a 1-2% improvement since the new lowered CG is only 3-4% lower times the correction factor of the track width.
I have lived with a set for the last 52,000 miles.
The front/rear springs must be secured [top and bottom] with tie wraps as on a severe rebound they will rattle in the perch.I am think of going back to stock when the current shocks wear out by Xmas [rear 60k].......yes the tokicios and oem [front 40k] last about half as long with the lowered springs!
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
There is static loaded negative camber at the correct body height and there is the EXTRA NEGATIVE camber curve created by the suspension as the body moves up and down from the normal position.......to help hold the tire near perpendicular under load as the sidewall deforms under the cornering load
X X X X X X.........normal ride height X...........Eibach lowered height X XX
The problem with lowering a car is that the upward rebound [back to normal] actually makes the camber less negative at 1" up then takes 2" up to go back towards the more negative curve.
A static -1.5 goes to -0.8, then back to -1.5, then to -2.0, then 3.0 instead of a smooth 0.8, -1.5,-2.0,-3.0,-3.7.
This oddity can make a 1-2" sway [0.2-0.4 G] feel funny in the first part of transition.
Many companies make aftermarket relocation kits for suspension points on lowered cars [but not Nissan].http://www.auto-ware.com/setup/cam_curv ... amber.html
When you lower a Q the rear mounting point angle of the upper link drops, raising the front of upper link relative to the rear........you can fix the STATIC CAMBER with adjustable upper links but do nothing about the abnormal camber curve....except learn to drive with it.
When you brake the front drops so the more negative camber you have on front tires, the Eibach springs help reduce the amount of drop so apples to apples while you may run around with an EXTRA 0.8 degrees under medium braking the TOTAL negative camber may not exceed oem since the springs allow less compression......but in a max mimum stop, the springs will still allow the camber to exceed oem......spring help but extra camber hurts....as you have an extra 1100 pounds shifted forward or about 1750 pounds per front tire.
This is why going to a higher load rating [from 1521 to 1610 or 1640] helps braking a few feet.
Other than looks the lowering springs don't help much and in the aggregate ........the cost - tire replacement and or adjustable upper links.
EXCESS Camber adversely effects braking and acceleration but -1.0 to -0.7 is just right for most single ply sidewall tires depending on inflation......dual ply sidewalls can get by with a little less -0.7 to -0.5 degrees.
X X X X X X.........normal ride height X...........Eibach lowered height X XX
The problem with lowering a car is that the upward rebound [back to normal] actually makes the camber less negative at 1" up then takes 2" up to go back towards the more negative curve.
A static -1.5 goes to -0.8, then back to -1.5, then to -2.0, then 3.0 instead of a smooth 0.8, -1.5,-2.0,-3.0,-3.7.
This oddity can make a 1-2" sway [0.2-0.4 G] feel funny in the first part of transition.
Many companies make aftermarket relocation kits for suspension points on lowered cars [but not Nissan].http://www.auto-ware.com/setup/cam_curv ... amber.html
When you lower a Q the rear mounting point angle of the upper link drops, raising the front of upper link relative to the rear........you can fix the STATIC CAMBER with adjustable upper links but do nothing about the abnormal camber curve....except learn to drive with it.
When you brake the front drops so the more negative camber you have on front tires, the Eibach springs help reduce the amount of drop so apples to apples while you may run around with an EXTRA 0.8 degrees under medium braking the TOTAL negative camber may not exceed oem since the springs allow less compression......but in a max mimum stop, the springs will still allow the camber to exceed oem......spring help but extra camber hurts....as you have an extra 1100 pounds shifted forward or about 1750 pounds per front tire.
This is why going to a higher load rating [from 1521 to 1610 or 1640] helps braking a few feet.
Other than looks the lowering springs don't help much and in the aggregate ........the cost - tire replacement and or adjustable upper links.
EXCESS Camber adversely effects braking and acceleration but -1.0 to -0.7 is just right for most single ply sidewall tires depending on inflation......dual ply sidewalls can get by with a little less -0.7 to -0.5 degrees.
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Q45tech
- Moderator
- Posts: 14296
- Joined: Tue Apr 30, 2002 3:19 am
- Car: 1990 Q45 342,400 miles 22 years ownership with original engine
1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
The 90-93 Q all have the same springs [166# Front-122 # rear]and shocks except for Active models.
{{{{The actual wheel/tire spring rates are a function of the tires in series with the springs and the friction of the shocks and the angular offsets of the springs ......reduce the published rates by around 10%}}} ..........so 150 and 110 respectively yet the static weigh is 53/47 [depending on gasoline level]
The t car has a additional 15.9 mm rear sway bar and a smaller front 28 mm sway bar.The t rear is 10% stiffer and the front is 6.5% softer if the bushings are tight [this is not true during the first 1-2" of body roll as the bushings are compressed absorbing the bar forces FIRST...........the key to understanding is what are the relative roll stiffnesses front and rear vs the weight ratio front and rear vs the roll instant center [height] front and rear.
in a curve at x speed y G's are created how equally balanced are the loads on the front and rear tires determines the steering wheel angle.
The HICAS on the rear had to do with letting the rear swing out and tucking it in at the appropriate place in the curve: turnin, midpoint of curve and powering out.How many of you brake before the curve starts, downshift, let off the brakes, then accelerate WOT from the midpoint [APEX] out to the end!.................this is the way you are supposed to drive.......even a stock non t Q has sufficient rear toe in compliance under decleration [brakes or engine gears] to correct the going in setup if you down shift to 2nd before the curve......hopefully you don't let the speed drop below 22-25 mph so 1st is engaged at WOT.
The brakes are 4 times stronger in decleration than the engine thru a down shift gear especially second until around 50 mph [3700 rpm] but the engine is smoother than most can modulate the brakes.
{{{{The actual wheel/tire spring rates are a function of the tires in series with the springs and the friction of the shocks and the angular offsets of the springs ......reduce the published rates by around 10%}}} ..........so 150 and 110 respectively yet the static weigh is 53/47 [depending on gasoline level]
The t car has a additional 15.9 mm rear sway bar and a smaller front 28 mm sway bar.The t rear is 10% stiffer and the front is 6.5% softer if the bushings are tight [this is not true during the first 1-2" of body roll as the bushings are compressed absorbing the bar forces FIRST...........the key to understanding is what are the relative roll stiffnesses front and rear vs the weight ratio front and rear vs the roll instant center [height] front and rear.
in a curve at x speed y G's are created how equally balanced are the loads on the front and rear tires determines the steering wheel angle.
The HICAS on the rear had to do with letting the rear swing out and tucking it in at the appropriate place in the curve: turnin, midpoint of curve and powering out.How many of you brake before the curve starts, downshift, let off the brakes, then accelerate WOT from the midpoint [APEX] out to the end!.................this is the way you are supposed to drive.......even a stock non t Q has sufficient rear toe in compliance under decleration [brakes or engine gears] to correct the going in setup if you down shift to 2nd before the curve......hopefully you don't let the speed drop below 22-25 mph so 1st is engaged at WOT.
The brakes are 4 times stronger in decleration than the engine thru a down shift gear especially second until around 50 mph [3700 rpm] but the engine is smoother than most can modulate the brakes.