Anybody ever see this thing, I was checking something under my car today and saw the sway bar, that sucker must be a 1 1/2", it is huge, bigger than the ADDCO bars I put on my 300ZX (1 1/4").
With the addition of my 17" rims and 245/45 Yoko ES100's (which are not broken in) it is like a different car, I feel like I throw it into the turns, the sidewall is so much stiffer. I can take turns 10-15 MPH faster now than I used to be able to. Big difference, but the touring 2nd gen is pretty stiff with those big sway bars and the strut brace bars....
Sway Bar on 97 Q45t
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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
Don't just look at a bar's diameter [you will be fooled] as the right angle arms that twists it are the key. Plus of course all the convolutions........flattened parts, etc.
A same diameter bar with 12" right angle arms will be half as stiff as a 6" right angle one.
Where the bar attaches to the suspension arm [or strut] is the key to how [much] the ratio of bar stiffness to resulting wheel stiffness gets transfered.
A bar that attaches to the mid point of an arm will move only 1/4 as much as the wheel moves.
Most front bars are within 10-25% of each other just as most front springs are within 10-25% of the same wheel rate.
The is a narrow range of stiffness [spring and bar] vs weight that accomplishes a good ride and the 20% stiffer is the limit for the street.
As most same sized cars have the same weight on each front tire within a narrow range 1200 to 900 pounds.A G35 might have 955 vs a Q with 1160 ~~~~ 200 pounds difference means at most 100 pounds /3" = 33 pounds per inch [20%] difference in bar stiffness between the models.
If you look at the 300zx, J30, M45, Q45 all the springs are within 10-15% of the same stiffness.
A same diameter bar with 12" right angle arms will be half as stiff as a 6" right angle one.
Where the bar attaches to the suspension arm [or strut] is the key to how [much] the ratio of bar stiffness to resulting wheel stiffness gets transfered.
A bar that attaches to the mid point of an arm will move only 1/4 as much as the wheel moves.
Most front bars are within 10-25% of each other just as most front springs are within 10-25% of the same wheel rate.
The is a narrow range of stiffness [spring and bar] vs weight that accomplishes a good ride and the 20% stiffer is the limit for the street.
As most same sized cars have the same weight on each front tire within a narrow range 1200 to 900 pounds.A G35 might have 955 vs a Q with 1160 ~~~~ 200 pounds difference means at most 100 pounds /3" = 33 pounds per inch [20%] difference in bar stiffness between the models.
If you look at the 300zx, J30, M45, Q45 all the springs are within 10-15% of the same stiffness.
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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
For safety sake with average divers who have no skills and panic in emergencies [like applying the brakes in a curve-------instead of before the curve], [not accelerating following the apex, etc] the front bars are overly stiff.
Reducing the front bars while adding rear stiffness always results in a more neutral steering car [in dry].
Cars with McPearson struts have no camber gain so they may need to add stiffness to the front bar and add an extra stiff rear bar............but cars like the 90-96Q which has tremendous camber gain can soften the front bar and gain handling pontential [like what was done in the active and t car], the front 29mm bar was reduced [13%] to 28 mm when rear bars were added.Since the springs and bar were roughly the same [13/2=6.5%] more roll 3.3" x 0.065=2/10th of an inch more front roll went unnoticed unfelt! vs the 3/4" reduction in rear roll......with 20 mm rear bar.
Reducing the front bars while adding rear stiffness always results in a more neutral steering car [in dry].
Cars with McPearson struts have no camber gain so they may need to add stiffness to the front bar and add an extra stiff rear bar............but cars like the 90-96Q which has tremendous camber gain can soften the front bar and gain handling pontential [like what was done in the active and t car], the front 29mm bar was reduced [13%] to 28 mm when rear bars were added.Since the springs and bar were roughly the same [13/2=6.5%] more roll 3.3" x 0.065=2/10th of an inch more front roll went unnoticed unfelt! vs the 3/4" reduction in rear roll......with 20 mm rear bar.
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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
Also forgot to mention the angle of the bar arm, obviously a right angle arm will couple more twist to the main bar section.Use trig to calculate the angle [force correction] - or + from the 90 degree point.
Unless the bar is perfectly shaped I__________I, none of the publish formula work. The factory has complex models which they try to follow or they build a bar that fits then measure it and decide upon the diameter, make this model and measure it and iterate the correct or closest value and live with it.
There is a $18,000 program to design complex sway bars but most have in house jury rigged programs that get close, plus dozens of engineers [with years of experience] that can just look at one and guess pretty close..........VP in charge of springs and bars. Who must work with the VP of bushings.
When you look at the 90-95Q rear t bar why did it become 15.9 mm not 15 or or 15.5 or 16 mm vs the 20mm rear active bar?.
15.9mm=0.625" = 5/8"............20mm=0.787"=25/32"..........maybe these were standard hollow pipe stock sizes?
Unless the bar is perfectly shaped I__________I, none of the publish formula work. The factory has complex models which they try to follow or they build a bar that fits then measure it and decide upon the diameter, make this model and measure it and iterate the correct or closest value and live with it.
There is a $18,000 program to design complex sway bars but most have in house jury rigged programs that get close, plus dozens of engineers [with years of experience] that can just look at one and guess pretty close..........VP in charge of springs and bars. Who must work with the VP of bushings.
When you look at the 90-95Q rear t bar why did it become 15.9 mm not 15 or or 15.5 or 16 mm vs the 20mm rear active bar?.
15.9mm=0.625" = 5/8"............20mm=0.787"=25/32"..........maybe these were standard hollow pipe stock sizes?