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Swar bar tech/theory


chris r

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I have been pondering this for a while. My shuttle is very under steery- Yes I need to improve my driving style. It has no rear sway bar from factory. I am planning on putting a stock one out of another Ef in it which from what I have read will help with understeer?

 

With the links from swaybar to the lower control arm do the links have to be vertical at rest or can they be at a angle with no issues?

 

I have done a terrible ms paint pic. The black is the subframe and LCAs and orange is my proposed links. red is sway bar. (the sway bar will be horizontal of course and not like the picture)

 

I am thinking there could be some binding if the distances change throughout the suspension movement? 

 

Who can school me on sway bar theory?

 

sway%20bar_zps7co3sfil.png

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Ideally you would want them to be vertical and aligned with the end of the bar (or as close as possible) in the plane that have you drawn them. Rear sway bar will make a massive difference to how the car turns in. I went from nothing to a 19mm bar on my Integra, already had a 22mm bar upfront, and it was a dramatic improvement.

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My Drawing is excessive on the angles but it was more to demonstrate what I have found. I do think it will bind up. 

 

Thanks for the articles

 

The links will be at a angle because the convenient holes in the LCA do not line up with the sway bars I have come across. Shuttles never had a rear sway bar from factory so I am trying to find something that will work.

 

I will get some photos of what I am working with

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Modern FWD cars are set up to under steer. putting a rear sway bar on will help a bit it won't fix what is in effect a safety net.

Basically the car under steers so you lift of the gas shifting the weight of the car to the front wheels allowing the car to get round the corner, not to mention the butt clench that trains the driver to slow down.

The biggest bang for buck will be lower and stronger springs followed by a more aggressive wheel alignment, the difference in turn in is astounding.

To really combat under steer, reduce ride height, increase spring weight, fit urethane bushes, adjustable top plates and a strut brace.

Wheel alignment for fast road work, between 0.5 and 1.5 deg negative chamber and a couple deg extra caster to reduce the tram lining using heavier springs will aggravate.

REDUCE UNSPRUNG WEIGHT so what you do actually gives you a real benefit. I know fitting a smaller wheel and tire with some side wall seems counter intuitive in this world of bigger is better and low profile tires but when it comes to wheel weight it works.

I know race cars have low profile tires and huge negative chamber but if you actually had to drive one for a week in the real world on real roads you would want to give it back the first day.

 

FWD corner technique is.

Slow in fast out.

Slow the car down before the corner, turn in a little later than what fells comfortable, hit the gas and let the power pull you out.

Good on you for wanting your Shuttle to behave badly, there's to many rules and to many haters.

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Thanks for everything, My honda is 4wd Yes they made them.

link is german but shows it http://www.hondaoldies.de/Korbmacher-Archiv/Technik/rt4wd.htm

 

I have lowered uprated springs and shocks replaced all bushes. Alignment will be done when its back together. I have done all the bushes. and have front/rear strut bars Wheels are fairly light weight and 195 tires aren't too excessively big? 

 

Lots of it will come down to my driving style and lack of skill. I know a sway bar in the back will not magically make it heaps better- I was more aiming to do some learning and if it makes a difference its good. What I found was it didn't want to turn in at all and would just plow on straight ahead.

 

Here is a old video of my horrible driving. The first turn you can kind of see it. It is higher in the front now than in the vid

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I went from no rear bar to maybe a 20 or 24mm one.

Made a massive difference. Too much for my liking and I went to around a 19mm.

On a fwd Nissan.

My technique was/is, come in to a corner real hot, and wide as possible. Brake hard as you start to turn then let off. Stab the brakes a bit when it starts to understeer for some weight transfer which gets you pointing the right way then apply as much power as you can without wheelspin.

Works well on mt messenger...

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honda call it real time real time 4wd I am aware its not 'proper' 4wd Mine is the intrac so has no viscous coupler in the drive shaft. Dont know if it has one in the doff or not. Will have to pull it apart one day and find out. Its the diff towards the bottom of that link.

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Modern FWD cars are set up to under steer. putting a rear sway bar on will help a bit it won't fix what is in effect a safety net.

A number of friends who run track or road sprint cars rave about fitting larger rear sway bars on their FWD's.

I personally run the largest factory rear swaybar available on my Corolla. But biggest handling upgrade I've done (ignoring decent tyres) is playing with spring rates. Last time out I tried 6kg fronts and 6.2kg rears (vs 8kg/6kg and 6kg/4kg previous days). Could be full throttle on or just before the apex and you'd feel the car still rotating after the apex. No understeer in sight.

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A number of friends who run track or road sprint cars rave about fitting larger rear sway bars on their FWD's.

I personally run the largest factory rear swaybar available on my Corolla. But biggest handling upgrade I've done (ignoring decent tyres) is playing with spring rates. Last time out I tried 6kg fronts and 6.2kg rears (vs 8kg/6kg and 6kg/4kg previous days). Could be full throttle on or just before the apex and you'd feel the car still rotating after the apex. No understeer in sight.

 

This ^    back in the day when i had a fwd starlet.  was a big upgrade in handling adding a rear  bar (they dont have one factory)  

 

try dial in as much grip up front first with camber caster and track.  then may get away with less rear bar so don't  get issues lifting a rear wheel as above

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From the look of that video there is far more going on than just a lack of swaybar. Trying to turn on loose gravel like that is always a mission, so the best way to get rid of understeer is a more generous application of handbrake, then pin it to come out of the turn. (Skids for kids etc) 

 

My list of things to look at before changing the bar would include: 

  1. Front shock condition
  2. Tyre condition
  3. Spring rates 

 

Swaybars are another spring in the suspension system and they work on vertical movement, so your links need to be fairly close to vertical to make them work. See the below pic - the suspension needs to push the bar up and down. You can also mount the bar below and have the links pointing up if there's space. 

 

Sway_bar_illust1.jpg

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Shocks and tires have been changed since video, handbrake slides are gay with this (yes its not true 4wd) but the hand brake still wont lock the rear it just slows everything down. I think the easiest thing to do will be re drill the trailing arms to suit the bars I have.

The video has a severe lack of driver skill too. 

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