96sleeper

iTrader: (4)

I was reading a magazine about european car tuning and it seems like the way that most of their performance cars are designed with three key things, a very stiff chassis, softer springs, and firm shock damping. My friend's M3 seems to be exactly like this, very good handling, firm ride, but still rides good and takes the big bumps easily without throwing you out of the car.
It seems that we go about suspension tuning the wrong way completely. We have to put on stiff springs to get good handling, which is the wrong way to go about it because the ride is too stiff in all road conditions besides smooth pavement (which doesn't exist). I was thinking that with all the braces (FSTB, RSTB, RSB), and with the addition of warpspeed's subframe connectors, that our cars would have a significantly stronger structure. Then with the addition of AGX's or Koni's to either stock springs, or H&R springs, then that would yield the best of both worlds in handling and ride comfort. The other springs really lower so much that there is no suspension travel and the ride over big bumps is too jarring. My car handles very good on smoother roads, but if there is a rut or a bump in a turn it is very dangerous to take fast because the car will fly off the road. I enjoy a firm ride now, but when I get older I would like a better balance between comfort and handling.

NmexMAX

iTrader: (22)

It's all in the physics, the moment you turn your steering wheel, the car leans, and to stop the lean, springs should be stiff, or the shock setting (if applicable) should be stiff. but in order to have all this stiff stuff, the entire chassis should be stiff. So in the end, stiffness is a good thing

Jeff92se

iTrader: (82)

Not it's not.

Nealoc187

iTrader: (23)

Do you want to have good handling on rough /broken pavement or on smooth pavement? Personally I'd rather have it on smooth pavement.

NmexMAX

iTrader: (22)

I was studying my physics book now, so sorry

Jeff92se

iTrader: (82)

You stand corrected.

NmexMAX

iTrader: (22)

Yeah, I hope my teach doesn't say that


But stiffness is a good thing to have when modding susp. Cuz that's what the FSTB, and rear anti-sway bars do......Back to studying though..

iwannabmw

iTrader: (3)

Stiffness IS a good thing

Jeff92se

iTrader: (82)

If stiffness is so great, then why do automotive engineers spent millions in suspension developement? Why not just afix all 4 wheels with no suspension travel at all? That's the stiffest/best right?

Ask him that.

NmexMAX

iTrader: (22)

hehe, Hehe, Huh, he sed stiph! Oh oh bet this threads gonna get locked now

iwannabmw

iTrader: (3)

Uh, Jeff, that wasn't what I was getting at, don't take everything so seriously

Jeff92se

iTrader: (82)

I know what you were referring to. I was trying to get this thread out of the gutter.

iwannabmw

iTrader: (3)

Oh, I thought every thread around here ended up in the gutter

mzmtg

iTrader: (11)

I'd rather have it handle well on rough pavement. As mentioned above, smooth pavement doesnt really exist. Plus, if your car can handle the bumps well, then the smoother parts are nooooo problem.

NightRider

iTrader: (6)

This is exactly what I've been telling folks. Stiffer springs does not necessarily give you better handling. Having these Cattman Coilovers will help you learn that. A lot of people will argue that if you want your car to handle better, then stiffer springs are in order. The only reason you get stiffer springs is to limit suspension travel so that you car doesn't hit the ground when it hits a bump after you lower it. Instead, you can use softer springs and use stiffer struts as well as firm bumpstops to keep from bottoming out. Stiffening up the chassis can make the car more ridgid and predictable, but it doesn't improve handling. The best handling improvement you can make is a confident driver. I now use softer springs with my Coilovers and made up for it by adjusting my RSB to full. Cattman can learn a thing or two about choosing spring rates too. We don't have 50/50 weight distribution.

Jeff92se

iTrader: (82)

Not all true but good points. A stiffer chassis is very desirable. Why? Because it allows you to use softer springs to achieve the same handling + the ride is not has harsh. Also a flexy chassis will introduce unwanted suspension geometry during hard corning. So a stiff chassis is good. It's one of the reasons car makers spend alot of money to stiffen the chassis. It leads to less creaks and groans and allows the maker to use softer suspension settings to achieve the same or better handling.

NightRider

iTrader: (6)

You are exactly right. However that unwanted suspension geometry won't make your car any slower in the turns, it just gives you an unsettling feeling, causing you to back off the throttle a bit. I totally agree and started changing the way I set up my suspension. Remember guys, we don't have 50/50 weight distrubution. More like 70/30. I think that a Maxima with a FSTB, and Sub frame connectors, with 300 lb. springs up front and 175 lb. springs in the rear on a 2.25" drop will give you the best handling and ride quality combination. The use of urethane bumpstops and/or short body struts will eliminate bottoming out. This will be the setup I'm going with next summer.

Jeff92se

iTrader: (82)

Uh yes it will. The reason you back off is yes, becuase it's unsettling. It's unsettling becuase the tires are now going every which way. So even if you don't back off, the car will not corner as well as an indentical car w/ a stiffer chassis.

wdave

The reason for having heavy springs in the rear on a rwd car is to get it to rotate in a turn - you can get a feel almost like rwd. Track fwd cars are commonly set up with the rear springs 50% or more stiffer than the front to dodge the dreaded understeer. For example, a Motorola cup (now grand am)Integra might have 500lb front springs, no front swaybar and 750 - 1200 lb rear springs and a rear swaybar. While this is extreme for the street the proportions are illuminating.
What the Max really needs in addition to more chassis stiffness is some caster for directional stability and some negative front camber for cornering.
The European philosophy of shock tuning is to have rebound damping as much as 4x the compression damping - something the Japanese still havent caught on to. This gives good control of the springs and body motion without the harsh ride.

NightRider

iTrader: (6)

Hey you know your stuff!! You are exactly on point with the concept of European tuning. I've actually been studying this for some time now, because I've been trying to get the best streetable performance setup. I've looked to BMW and Porsche as inspiration. The reason that I said that the stiffer suspension won't make the car turn faster is because the Maxima is an optimum handling car to begin with. I push my car to the limits everyday, even when I first got it. The Maxima used to outhandle many other automobiles and had excellent traking as well. The exessive flex and body roll does cause you to get scared, but you can still safely push the car further than expected. By eliminating flex, the driver feels as if he/she has more control, therefore pushes the car harder.

rob van dam

iTrader: (4)

that suspension set up sounds like it would work..BUTTTTTTT!!!!!....THE CAR WOULDN'T BE LOWERED AND WE WOULD STILL HAVE THE HORRIBLE WHEEL GAP......!

Jeff92se

iTrader: (82)

Nope. The stock maxima suspension is FAR from optimium. Way too much understeer dialed in from the factory.
A stiffer chassis makes for less unpredictable suspension geometry when the car is cornered hard. It's not just "felt", it's real. Just think of your car as a stick with 4 wheels. Then think of the angles the wheels will be at if you twist that "stick".

wdave

Body roll is not really a handling problem except in quick transients - the old Renauld Cup racers looked and felt kike they needed rollers on the door handles but stuck like glue in the turns. Low lateral stiffness is actually good for cornering stick - just feels terrible. The way a swaybar really works is that it takes grip away from the end of the car it's on to improve overall balance.
Chassis stiffness is a major issue in both handling and ride. The chassis must be stiff to let the suspension work as designed. A stiff chassis will also allow the suspension to be tuned for more comfort without unwanted wheel motion.
Lowering a car will generally improve handling by lowering the center of gravity. The trade -offs are that the springs have to get stiffer to keep the car off the bump stops and the lowering can put the suspension in a poor part of the camber gain and bump steer curves.

BUT!!! If a car's suspension design is lousy to start with, the best way to improve it is to limit motion! The 4/5 gen Maxes are severely compromised in design. Aside from being woefully nose heavy the actual McPherson Strut/Beam axle arrangement stinks. Struts have very little if any camber gain on roll - once the lower control arm passes horizontal with the outer end moving up (outside - working hardest - tires) the gamber gain is actually negative - UNDERSTEER, and lowering actually makes this worse.
The rear is a whole different ballgame. The twist beam axle itself isn't so bad - Rabbits used it very well. The Max, however, has that Rube Goldberg transverse link (to save trunk space). The unsprung weight is pretty low. Unfortunately, both available rear swaybar designs, while helping handling tremendously, increase unsprung weight, a compromise again. The transverse link has way too much rubber give. Although it needs some give for the peculiar motion of its' intersecting arcs, a well designed bushing kit would be a major blessing. Nobody, surprisingly, has offered one yet - and probably won't as the most common attitude toward rear suspension on fwd cars is that it's just there to keep the gas tank from dragging.
Proper shocks would really help - stiff in rebound, soft in compression (the opposite of KYB GR2 or Gas Adjust). GAB makes such a shock - double adjustable, among others - but none for the Max. Tokiko Blues are close in valving but don't seem to last. We suffer from the wrong image - there's no speed equipment for Camry, Taurus etc. either!

CFster

A good example is the British American Racing Formula 1 car last season. They had unpredictable handling and couldn't understand why. It turned out that under braking the nose of the car was flexing and completely changed the suspension geometry - not to mention aerodynamics. They knew they had a problem but couldn't do anything - it would have required a completely redesigned chassis.