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Impressions of my huge rear sway bar

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Old 09-07-2005, 09:36 AM
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norvalwilhelm
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Default Impressions of my huge rear sway bar

I know I am from the C3 section but some of you might find this usefull

As you know I installed a 1 1/4 inch speedway bar on the back to go with my 1 1/4 inch front bar. The front is extremely stiff with a 1/4 inch wall tube. It is alot stiffer then the 1 1\8th in solid bar. For the back I used 3/16 wall tube.
I also used bearing blocks on the front and bushings , but good fitting bushings on the rear and 8 rod ends in total for the 2 bars.

After installing the bar I took the car for a short ride to settle the suspension and then adjust the linkage so there was no preload on the sway bar. I found the bar in this short run extremely stiff. The car felt like it had really stiff springs.

Last night I took it for it's first real run. Carguy4sure and I went 50 miles across country to a show. 25 each way.
As I started cruising at 60 I found the bar seems to smooth out, the ride was not harsh like slow speed in town. I even put the outside wheel close to the rought edge of the road to make that side work and it felt really smooth.
I entered a few corners at about twice the recommended speed and found myself accelerating as the corner became more comfortable and would come out of the corner 15 or 20 mph faster then when I went in. I also lost my buddy Doug.
I also found not once did the car ever feel twitchy. My car is not bad but occasionally you feel that twitch. It seems to be gone. Maybe our twitch is comming from the rearend??
I feel it was a big improvement over last week without the bar. It was worth the roughtly $350 I put into the project.

The reason I went with the huge rear sway bar is because of an article I read from Herb Adams and talking to twin Turbo. 2 very knowledgabel guys.

This was taken this morning from Corvette action, posted by Kid Vette but it is taken from Herb Adams, This is what convinced me a few weeks ago.
Agian I took this from KID Vette/Corvette action/Herb Adams

Here's Herb Adams direct quote, "One reason we recommend larger, more effective stabilizer bars for Corvettes is the bars' ability to control a car's understeer characteristics. Standard Corvettes are produced at the factory with a great deal of understeer built into their suspensions.Anyone who has driven a Corvette hard into a corner has probably experienced understeer. The car "plows" or "pushes" through the corner. Regardless of the term used to describe the condition, the front tires must be pointed more into the turn to keep the car on its line (see diagram A). Oversteer is the opposite effect: the front tires are pointed outward, and the car is said to be "loose" or "hanging out" (as in diagram B). Neutral steer is the middle ground between oversteer and understeer. Both the front and rear tires are running at the same angle to the road. A Corvette set up for neutral steer will be faster in steady state cornering than one which over- or understeers because all four tires are sharing the cornering loads equally. By using the recommended stabilizer bars, your Corvette will become very close to the desired neutral steering attitude.

Factors such as the number of people in the car, road conditions, vehicle speed, and other variables can influence the handling characteristics of your car. Driving technique can compensate for these small changes if the car is close to the neutral state. In some special circumstances a slight degree of oversteer is beneficial. Certain autocross courses, for example, favor a car which oversteers somewhat. In general, though, you will probably be most comfortable in street driving conditions with a car set up to corner with a very slight amount of understeer.
It is necessary to control body roll on cars with independent suspensions because there is little anti-roll effect built in. Stabilizer bars control body roll by requiring the bar to be twisted if the body is to roll. Since larger diameter bars are harder to twist, they are more effective in limiting body roll. Stabilizer bars are used to control body roll because they have little effect on the up and down motions of the suspension. Stiffer springs can also be used to control body roll, but they also decrease the suspension's ability to absorb bumps so the ride quality is poorer.
Some of the reasons it is necessary to control body roll in cornering are for driver and passenger comfort, to limit the effects of roll steer, and to limit the loss of cornering power due to camber change. If a car rolls at too great an angle driving around a corner, like a Renault, the passengers feel like the car will tip over. Since the Corvette suspension has a considerable amount of roll-steer built in, this unwanted steering effect is reduced if body roll is reduced (roll steer is that part of the suspension geometry that causes the wheels to steer toward understeer as the body rolls.) GM always builds this into their cars on the premise that it makes them safe in spite of the driver's abilities. Performance minded drivers don't need much protection for themselves, so they don't need much roll steer.

The camber effects of body roll are caused by the fact that, as the body rolls, the tires roll with it. This causes the camber to increase on the outside tires, which reduces their cornering power, if body roll is minimized, the outside tires can remain perpendicular to the ground and deliver maximum cornering traction. The best way to limit body roll is to install bigger (and therefore stiffer] stabilizer bars. It is also an advantage to connect the stabilizer bars to the control arms with steel joints lo eliminate lost motion.

If a car, such as a Corvette, is equipped with both a front stabilizer bar and a rear stabilizer bar it is possible to control the amount of understeer and oversteer. When a larger rear stabilizer bar is used, the car will move toward the oversteer side of handling. If a large enough rear bar is used, the car will oversteer."
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Old 09-07-2005, 02:28 PM
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bcwaller
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Interesting. Thanks for the update, Norval, as I like to follow your modifications. Have you compared the feel when going into driveways or across speed bumps at an anle. I've often noticed that taller cars (and SUVs) with large bars seem to really rock due to the bar when angling across something. But I'm not sure the the effect would be nearly the same with a low Corvette

From what I've seen, there are two philosophies for handling. One that uses stiff springs and mild bars, and the other that uses mild springs and big bars. I know you are obviously a big fan of the soft springs, so this makes sense that you would be follwing the big bar route.
Old 09-07-2005, 04:08 PM
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norvalwilhelm
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I find crossing a bump at an angle is really rough. At low speeds the car seems alot harsher but once at speed it really smooths out.
yes I like the soft springs and heavy bars. I do value ride quality. I also feel the harsh springs don't follow the road as well. The tire bounces over the bumps rather then follow the contour.
Old 09-07-2005, 05:57 PM
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65 Hardnoks
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Wasn't understeer built into the suspension to allow for more acceleration through and out of a corner? It seems to me that neutral steer would be good for coasting around a corner but the car would break loose if the throttle was pressed.

I took the bar off the back of my C2 because it always broke loose when I mashed the throttle around a corner. Now it just digs in and goes.
My J30t Infiniti is has understeer as well but it digs right in if you mash the gas through a corner.
Old 09-07-2005, 07:33 PM
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Originally Posted by norvalwilhelm
I know I am from the C3 section but some of you might find this usefull

As you know I installed a 1 1/4 inch speedway bar on the back to go with my 1 1/4 inch front bar. The front is extremely stiff with a 1/4 inch wall tube. It is alot stiffer then the 1 1\8th in solid bar. For the back I used 3/16 wall tube.
I also used bearing blocks on the front and bushings , but good fitting bushings on the rear and 8 rod ends in total for the 2 bars.

After installing the bar I took the car for a short ride to settle the suspension and then adjust the linkage so there was no preload on the sway bar. I found the bar in this short run extremely stiff. The car felt like it had really stiff springs.

Last night I took it for it's first real run. Carguy4sure and I went 50 miles across country to a show. 25 each way.
As I started cruising at 60 I found the bar seems to smooth out, the ride was not harsh like slow speed in town. I even put the outside wheel close to the rought edge of the road to make that side work and it felt really smooth.
I entered a few corners at about twice the recommended speed and found myself accelerating as the corner became more comfortable and would come out of the corner 15 or 20 mph faster then when I went in. I also lost my buddy Doug.
I also found not once did the car ever feel twitchy. My car is not bad but occasionally you feel that twitch. It seems to be gone. Maybe our twitch is comming from the rearend??
I feel it was a big improvement over last week without the bar. It was worth the roughtly $350 I put into the project.

The reason I went with the huge rear sway bar is because of an article I read from Herb Adams and talking to twin Turbo. 2 very knowledgabel guys.

This was taken this morning from Corvette action, posted by Kid Vette but it is taken from Herb Adams, This is what convinced me a few weeks ago.
Agian I took this from KID Vette/Corvette action/Herb Adams

Here's Herb Adams direct quote, "One reason we recommend larger, more effective stabilizer bars for Corvettes is the bars' ability to control a car's understeer characteristics. Standard Corvettes are produced at the factory with a great deal of understeer built into their suspensions.Anyone who has driven a Corvette hard into a corner has probably experienced understeer. The car "plows" or "pushes" through the corner. Regardless of the term used to describe the condition, the front tires must be pointed more into the turn to keep the car on its line (see diagram A). Oversteer is the opposite effect: the front tires are pointed outward, and the car is said to be "loose" or "hanging out" (as in diagram B). Neutral steer is the middle ground between oversteer and understeer. Both the front and rear tires are running at the same angle to the road. A Corvette set up for neutral steer will be faster in steady state cornering than one which over- or understeers because all four tires are sharing the cornering loads equally. By using the recommended stabilizer bars, your Corvette will become very close to the desired neutral steering attitude.

Factors such as the number of people in the car, road conditions, vehicle speed, and other variables can influence the handling characteristics of your car. Driving technique can compensate for these small changes if the car is close to the neutral state. In some special circumstances a slight degree of oversteer is beneficial. Certain autocross courses, for example, favor a car which oversteers somewhat. In general, though, you will probably be most comfortable in street driving conditions with a car set up to corner with a very slight amount of understeer.
It is necessary to control body roll on cars with independent suspensions because there is little anti-roll effect built in. Stabilizer bars control body roll by requiring the bar to be twisted if the body is to roll. Since larger diameter bars are harder to twist, they are more effective in limiting body roll. Stabilizer bars are used to control body roll because they have little effect on the up and down motions of the suspension. Stiffer springs can also be used to control body roll, but they also decrease the suspension's ability to absorb bumps so the ride quality is poorer.
Some of the reasons it is necessary to control body roll in cornering are for driver and passenger comfort, to limit the effects of roll steer, and to limit the loss of cornering power due to camber change. If a car rolls at too great an angle driving around a corner, like a Renault, the passengers feel like the car will tip over. Since the Corvette suspension has a considerable amount of roll-steer built in, this unwanted steering effect is reduced if body roll is reduced (roll steer is that part of the suspension geometry that causes the wheels to steer toward understeer as the body rolls.) GM always builds this into their cars on the premise that it makes them safe in spite of the driver's abilities. Performance minded drivers don't need much protection for themselves, so they don't need much roll steer.

The camber effects of body roll are caused by the fact that, as the body rolls, the tires roll with it. This causes the camber to increase on the outside tires, which reduces their cornering power, if body roll is minimized, the outside tires can remain perpendicular to the ground and deliver maximum cornering traction. The best way to limit body roll is to install bigger (and therefore stiffer] stabilizer bars. It is also an advantage to connect the stabilizer bars to the control arms with steel joints lo eliminate lost motion.

If a car, such as a Corvette, is equipped with both a front stabilizer bar and a rear stabilizer bar it is possible to control the amount of understeer and oversteer. When a larger rear stabilizer bar is used, the car will move toward the oversteer side of handling. If a large enough rear bar is used, the car will oversteer."
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Big bocks need rear bars. Small blocks don't. But if you insist and have a small block and want a rear bar, upsize your front bar. It's all about balance. Don't confuse people.
Old 09-07-2005, 08:22 PM
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norvalwilhelm
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Originally Posted by 65 Hardnoks
Wasn't understeer built into the suspension to allow for more acceleration through and out of a corner? It seems to me that neutral steer would be good for coasting around a corner but the car would break loose if the throttle was pressed.

I took the bar off the back of my C2 because it always broke loose when I mashed the throttle around a corner. Now it just digs in and goes.
My J30t Infiniti is has understeer as well but it digs right in if you mash the gas through a corner.
Yes understeer was built into the cars, it is safer for the general public but I like to push things. I was actually having a problem with cornering and braking with the rear end comming around. I also run into oversteer a few times.
I have true independent rear end with coilovers on each corner.
The heavy sway bar was an experiment to see how it would work. I only tested it for 50 miles but every corner I can to including the hard lefts and rights I took at a much higher speed then I felt comfortable with and every time part way through the corner I started increasing the speed. The car felt that stable. Theory is fine but real world seat of the pants testing is better.
I have never driven harder in the corners and had the car feel so good. The problem is to make the corners more chanllenging the speeds are getting too high so if I got into trouble it would be all over. 70 and 80 mph is beginning to feel slow and that is becomming too fast.
I am also experiencing carb slosh on the really hard corners. The motor coughs for a second while under maximum side loading.
From the limited seat of the pants testing last night over 50 miles of secondary roads I feel the large 1 1/4 inch bar was a big improvement for me.
Results may vary with individuals
Old 09-07-2005, 08:26 PM
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norvalwilhelm
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Originally Posted by MikeM
Big bocks need rear bars. Small blocks don't. But if you insist and have a small block and want a rear bar, upsize your front bar. It's all about balance. Don't confuse people.
I don't follow this??? Am I confussing people by posting my results???? What worked better for me??? To me there is no question about the improvement of the rear 1 1/4 inch bar in conjunction with a 1 1/4 inch front bar. Hopefully the two bars are working together. I do have soft springs but an increased spindle length of 1 1/2 inches to raise the roll center.
Again it worked for me, the twitchyness is gone, at least the limiting testing I did.
I also have a Jeep Cherokee box ready to install, That is a major winter project.
Old 09-07-2005, 08:29 PM
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norvalwilhelm
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Originally Posted by 65 Hardnoks
Wasn't understeer built into the suspension to allow for more acceleration through and out of a corner? It seems to me that neutral steer would be good for coasting around a corner but the car would break loose if the throttle was pressed.

I took the bar off the back of my C2 because it always broke loose when I mashed the throttle around a corner. Now it just digs in and goes.
My J30t Infiniti is has understeer as well but it digs right in if you mash the gas through a corner.
I can't ever just mash the throttle out of a corner. Not if I don't want to totally spin out. A few summers ago it let go in 3rd and I went totally around. Not a nice feeling.
I find I drive into a corner and part way through feeling the corner I then smoothly accelerate picking up about 15-20 mph exiting the corner.
Old 09-08-2005, 02:46 AM
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65 Hardnoks
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If you can't mash the throttle out of a corner like you want then you need to get rid of that rear bar or increase the poundage in the front springs. You could also get a less stiff rear spring ect ect ect.

If you want to mash the throttle coming out of a corner, the front has to be stiffer than the back when you are talking horsepower.

I didn't notice Herb Adams mentioning the horsepower #s or block size when he was talking about needing a rear swaybar.

The big block cars came with rear swaybars because they needed VERY stiff front springs to keep the nose from hitting the pavement because of the engines weight. A rear bar simply balanced the back to the front and effect the proper amount of understeer but not too much. The back was STILL less stiff than the front ( the same as the settup in smallblock cars without a rear bar).
Old 09-08-2005, 07:44 AM
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I can't even mash the throttle in a straight line.
Old 09-08-2005, 09:15 AM
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65 Hardnoks
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John Force has the same problem.

Last edited by 65 Hardnoks; 09-08-2005 at 09:52 AM.
Old 09-08-2005, 05:25 PM
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My experience with sway bars is very similar to Norval's - although my set up is closer to stock but with Koni shocks, 1 1/4" bar up front and 7/8" in the rear. Springs are 330 lb TRW in rear and Grand Touring (can't remember the lbs) on the front ( I think they are 550 lbs? maybe...) poly bushings.

Bottom line? Flat cornering at crazy speed with no tire slip or hop. I have slight oversteer when on the throttle but I like it. Most people that drive my car marvel at it's overall "tightness" - a little harsh at slow speeds on bad roads but at 65-85 mph very smooth and straight.

Adding the rear bar made a HUGE change in handling for the better.
Old 09-08-2005, 08:23 PM
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Originally Posted by pjmonfre
My experience with sway bars is very similar to Norval's - although my set up is closer to stock but with Koni shocks, 1 1/4" bar up front and 7/8" in the rear. Springs are 330 lb TRW in rear and Grand Touring (can't remember the lbs) on the front ( I think they are 550 lbs? maybe...) poly bushings.

Bottom line? Flat cornering at crazy speed with no tire slip or hop. I have slight oversteer when on the throttle but I like it. Most people that drive my car marvel at it's overall "tightness" - a little harsh at slow speeds on bad roads but at 65-85 mph very smooth and straight.

Adding the rear bar made a HUGE change in handling for the better.
Your rear bar is actually more effective then mine because you have the traverse rear spring. I have true coilovers so no movement from one side transfers to the other side except through the sway bar.
With a stock type setup smaller bars work more effectively then with coilovers.
Regardless of what anyone knows I found it worked really well for me in my limited 50 mile run. I will do another run with some fast guys saturday night.
Old 09-08-2005, 10:02 PM
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Originally Posted by norvalwilhelm
I also have a Jeep Cherokee box ready to install, That is a major winter project.
Norval, are doing the Cherokee steering box conversion? Please keep us posted.
Frank.
Old 09-08-2005, 10:24 PM
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Originally Posted by norvalwilhelm
Your rear bar is actually more effective then mine because you have the traverse rear spring. I have true coilovers so no movement from one side transfers to the other side except through the sway bar.
With a stock type setup smaller bars work more effectively then with coilovers.
Regardless of what anyone knows I found it worked really well for me in my limited 50 mile run. I will do another run with some fast guys saturday night.
I forgot about your coil overs! My rear bar might be a bit large but I still like the feel of it. I've put about 2500 miles on the set up with several 100 mile + runs and I really like it. I do need to dial in the shocks a little better but overall I'm pleased - and mine's a vert so I do get that shimmy but it's not bad.
Old 09-09-2005, 07:31 AM
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Originally Posted by 00fxd
Norval, are doing the Cherokee steering box conversion? Please keep us posted.
Frank.
Yes I am doing the cherokee box conversion. I feel it is better then Steroids and 1/2 the price although price had nothing to do with my decision which route to go.
There is a good kit on the market for $675. I have read lots of complaints witht the steroid setup and it runs $1249.

Check it out. This is also for vets.
http://www.corvettesteering.com/55-57%20chevy.htm

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