Can you guys think of any disadvantage to removing the swaybar if the suspension is already pretty stiff? They dont really offer that much "twisting" rigidity do they?

Why would you want to remove it? It's there to prevent body roll. If you remove it you'll certainly get more of that..

not necessarily true. many teams have experimented with very high spring rates and removing the swaybar.

I'm doing it. Of course, I'm doing it because I'm ghetto, not because I'm innovative. :)

Why would you want to remove it? It's there to prevent body roll. If you remove it you'll certainly get more of that..

Well, Im certainly not a suspension expert. But i am running relatively high spring rates already (400/290) and the front sway bar has given issues with the fujitsubo header for the VE. So i just wondered if it is really doing that much for me. With the rates i have, the car really shouldnt roll either way. Im just curious as to peoples opinions/experiences with this.

nathan

Back when I had a classic, I was running the suspension techniques (with tokico/prokit shocks/springs) bars and I removed the front one for a while, can't remember why, but the car was very very tail happy. I came into a 15mph exit ramp that I knew well at around 30 mph, and spun the car 1 1/2 times before I even knew what was happening. Needless to say I put the bar back on as soon as I could. I'd say take it off, then drive around an empty lot to get a feel for the new handling.

Sway bars do more than reduce body roll. They increase rate of weight transfer when yawing. Take both sway bars off and see how slowly the car takes a set when turning.

Transfer rate can be manipulated by altering spring rate of the bars; increasing front rate relative to rear increases understeer while increasing rear bar rate increases oversteer (as webninja discovered). This is the justification of adjustable sway bars; weight transfer rate is easily changed to allow tuning for conditions. Wet conditions are better handled with more front bias and less total roll resistance to slow transfer. Dry conditions with sticky tires want rear bias and fast transfer rate.

As spring rate goes up, sway bar rates usually go down as the weight transfer is handled by the stiffer spring. Lighter bars reduce connectedness of two sides, suspension control gets better when there's asymmetrical suspension deflection.

Sway bars do more than reduce body roll. They increase rate of weight transfer when yawing. Take both sway bars off and see how slowly the car takes a set when turning.

Transfer rate can be manipulated by altering spring rate of the bars; increasing front rate relative to rear increases understeer while increasing rear bar rate increases oversteer (as webninja discovered). This is the justification of adjustable sway bars; weight transfer rate is easily changed to allow tuning for conditions. Wet conditions are better handled with more front bias and less total roll resistance to slow transfer. Dry conditions with sticky tires want rear bias and fast transfer rate.

As spring rate goes up, sway bar rates usually go down as the weight transfer is handled by the stiffer spring. Lighter bars reduce connectedness of two sides, suspension control gets better when there's asymmetrical suspension deflection.

assymmetrical suspension deflection meaning each side of the car handles its own suspension geometry?

So are you saying that handling will improve with super high spring rates and no sway bar? All of this engineer talk has me confused. Like Billy Maddison said, T-t-t-Today Junior!

Frank

Yes, it's the same thing that Naji is doing with his race car. He removed the front sway bar and compensated by running 600+ spring rates in the front. From what I've gathered it is best to loose the sway bar and increase spring rate. But since most of us have street cars with no cages and don't want a super stiff spring, we compansate by adding a sway bar. Am I making any sense?

I removed my front swaybar for a month. I lost a whole bunch of transitional response, just as Bruce said. It was horrible, especially for autocrossing. I put my ST bar back on and I am back to being happy. I still don't have the lightning fast response I want, but it's good enough, and way better than the three-step turning process of the stock setup:

1. Turn wheel.
2. Wait for doorhandles to scrape.
3. Turn.

When I first put my GC/AGX setup on, I hit a lot of slalom cones because I had to turn so early before. That was funny.

EDIT: For sissy slow reaction stuff like Sunday drives and roadcourse racing, I'm sure it would be okay to remove the front bar. ;)

Bruce is spot on.

Total load transfer is not affected. Just the rate, or speed of the transfer. Body roll, in and of itself, is not the issue, at least not from a performance standpoint assuming springs may be replaced with higher rates.

For autocross I would never consider removing the front swaybar because that would slow down the transient response so necessary in autocross. For the race track I am planning on heavy springs and lighter bars for the reasons Bruce mentioned. I want the bars to tune the suspension but want to minimize the effect of one side of the suspension on the other side.

But, body roll IS an issue because of the horrible big camber and caster changes that the suspension goes thru when your body rolls a ton. Stiff springs can fix this, and sway bars can fix this, but as said before, for race cars the stiff springs are a better way to go if you can stand the ride. Otherwise, some balanced compromise between springs and sway bars is the usual route.

Many moons ago, one of the hot rod magazines wanted to illustrate the two approaches to suspension tuning (big springs, small sway bars vs small spings, big sway bars). According to theory, you want each side of the car total independent from the other so the asymmetrical stuff won't affect the opposite side. Otherwise, what's the point of IRS?

They pitted Dick Guldstrand and Herb Adams against each other using identical Formula Firebirds. Guldstrand is of the big spring persuasion while Adams preached big sway bar. After the dust settled, Adams' softly sprung, big sway bar Firebird was slightly faster around the track than Guldstrand's rock-hard riding Formula. Other than suspension, both cars were identical. This didn't really prove that Adams method was better, just that his method, much more suitable for the street, was no worse on the track than Guldstrand's typical race set up. The track was bumpy enough that the soft springs of Adams car kept the tires planted while Guldstrand's car did some skating. To ***, for a street car use as soft a spring as possible to give a good ride while staying off the bump stops and control roll and weight transfer with sway bars. Yes, this flies in the face of ideal design, but the world isn't ideal at all.

The MacPherson strut as used on the Sentra indeed has some issues regarding camber change. For a race car, super-stiff springs (>500 lb/in) needed to stay away from the bad portion of the camber curve makes sense though this will handicap the car on bumpy tracks. For a street car without a cage, it's pointless and ill-advised to run these spring rates.

Many moons ago, one of the hot rod magazines wanted to illustrate the two approaches to suspension tuning (big springs, small sway bars vs small spings, big sway bars). According to theory, you want each side of the car total independent from the other so the asymmetrical stuff won't affect the opposite side. Otherwise, what's the point of IRS?

They pitted Dick Guldstrand and Herb Adams against each other using identical Formula Firebirds. Guldstrand is of the big spring persuasion while Adams preached big sway bar. After the dust settled, Adams' softly sprung, big sway bar Firebird was slightly faster around the track than Guldstrand's rock-hard riding Formula. Other than suspension, both cars were identical. This didn't really prove that Adams method was better, just that his method, much more suitable for the street, was no worse on the track than Guldstrand's typical race set up. The track was bumpy enough that the soft springs of Adams car kept the tires planted while Guldstrand's car did some skating. To ***, for a street car use as soft a spring as possible to give a good ride while staying off the bump stops and control roll and weight transfer with sway bars. Yes, this flies in the face of ideal design, but the world isn't ideal at all.

The MacPherson strut as used on the Sentra indeed has some issues regarding camber change. For a race car, super-stiff springs (>500 lb/in) needed to stay away from the bad portion of the camber curve makes sense though this will handicap the car on bumpy tracks. For a street car without a cage, it's pointless and ill-advised to run these spring rates.

Man, that sucks for me. I just got some super stiff springs.

nathan

Anyone know how much the 600lb front springs go for? and where to get them cheap?

If you put 600lb springs on a B13 won't the chassis then be the suspension instead of the suspension being the suspension?

A caged Sentra is stiff enough to handle those big guns. Otherwise, you're right.

not necessarily true. many teams have experimented with very high spring rates and removing the swaybar.

I'm doing it. Of course, I'm doing it because I'm ghetto, not because I'm innovative. :)

This is true. But the sway bar is there to give more flexibility in suspension comfort. You can go with much stiffer springs and shocks/struts and remove the sway bar and still have very limited body roll but you'd bruise your kidney's trying to drive around in a car setup like that. If it's just for the track it's not a bad idea but unless I was planning on doing a major suspension change I'd leave it on.

Just thinking out loud here, but when the car goes into a turn, the swaybar is pushed up by the suspension traveling up into the wheel well, and this limits bodyroll since it is pushing up on the other side's suspension, forcing it to travel as well, and at the same time, this is causing the car to squat, lowering it's center of gravity as well, further reducing roll. So I can see softer springs and a stiff swaybar as being great for street driving, as it will allow the car to handle well on corners but maintain a liveable ride, assuming the strut valving is well matched to the spring rates, but also good on the track since the car is going to really hug. Now having super stiff springs and a soft swaybar, or no swaybar, even though the springs aren't going to compress that much, the car is still going to have more bodyroll due to the inside wanting to lift, also since the suspension isn't going to compress as much the center of gravity will stay higher, which isn't going to help cornering either. Needless to say it would suck on the street as well.

Plus softer springs work better than stiffer unless the road in question is really smoooooooth.

If you want to run w/o a front sway bar, then you need to run 600+ stiff springs. Anything less will not cut it. 600+ springs are a PITA on the streets though. This being the case, you need to run softer springs with a front bar to reduce roll.

On my race car I run 650 front and 550 rear w/o a front sway bar. In the rear I run 1 & 1/8 inch Progess bar set to full stiff. Even with this set-up the car is neutral to loose. The previous set-up was 500 front and 450 rear with a B13 front bar and a 22 mm N-tech rear fixed bar. The new set-up helped us shave 1.5 seconds off our time at Buttonwillow vs. the old set-up.

On my street car I run 300 front and 250 rear. These springs are too soft to run w/o a front swaybar. To compensate I am using a front B13 28 mm bar and rear fixed 22 mm N-tech bar. I set the AGXs to 3 front and 5 rear. The car is a blast to drive on the street and the ride is not punishing, but stiffer than stock.

Edit: I am posting under Jude's handle