“I’m a believer” in anti sway bars

[Itchief]

After driving about 5600 miles on the two lane roads in southern West Virginia I installed a VPM rear sway bar and I am very happy with with the results.

The car always handled well but adding the anti sway bar has made a huge difference in the way the car drives and handles. I plan to install the FFR front sway bar before the weather breaks this spring to see if it will make any difference in the way the car handles

Rick

[lance corsi]

Front sway bars generally make a more noticeable difference in handling than rear bars. Just my experience. It's definitely something to help tune the ride, along with adjustable shocks.

[Mike N]

Rick. The rear bar added roll stiffness to the back of the car. This means that during hard cornering it is now much more likely that the rear will break loose first. I would be extra careful until you install the front bar and re balance the car.

[CraigS]

Ck w/ Forte also on the front bar. He has them in different thicknesses. I recommend the 7/8 to go w/ your rear bar.

[BEAR-AvHistory]

Not a fan of bars for the street cars unless it has some weird handling issue that needs to be fixed. That said if you just have to have bars be sure to get the front on first. Its very easy to induce oversteer wanted & unwanted in these cars. A rear bar by itself will only add to this issue by increasing the tendency to oversteer.

[Jeff Kleiner]

With the factory 500/350 solid axle spring combination the roadster naturally understeers unless you induce oversteer with the throttle. Stiffening the rear with a bar or more spring will free it up; stiffening the front without a corresponding change to the rear will cause it to push even worse. Personally I can't stand a car that pushes...

Jeff

[Itchief]

I wanted to thank everyone for their suggestions and comments

After reading all the comments pro and con concerning sway bars I was surprised at how much better the car handles after adding the rear sway bar and yes the rear end does break loose more with the sway bar installed but most of that is cause by my foot on the throttle pushing through the turn. I will have to be very careful even after installing the front sway bar

Some information about the car setup may help the discussion

I am running a big block 390 with 550 lb 9 in springs up front and 250 lb 9 in springs in the rear

Measuring the spring compression and converting that to weight (redneck scale) my car weights about 2700 lbs with a full tank of fuel , 1700 lbs front and 1000 lbs rear that works out to about a 60/40 front/rear weight ratio

Rick

[Jeff Kleiner]

...I am running a big block 390 with 550 lb 9 in springs up front and 250 lb 9 in springs in the rear...

That setup has understeer written all over it and as you found out a rear bar can definitely help tame the push!

Jeff

[CraigS]

I know the 390 is kind of heavy but I have a hard time thinking it moves the weight that much. The typical FFR is about 52% rear heavy.

[BEAR-AvHistory]

WOW....can see why it is understeering, 60/40 is right up there in FWD class weight distribution. So you did have a something weird to fix

[Mike N]

The 550/250 spring rates are one reason why the car is working better with the rear bar. I believe the FFR standard spring rates for a solid axle car are 500/350. You have a 300 lb difference between front and rear rates where the standard FFR only has a 150 lb difference. With your rear bar you have very likely brought the roll stiffness back closer to the FFR designed rates.

[MPTech]

Have you scaled it?
60/40 sounds front heavy to me (even for a BBF). A friend in our club has a 460 and it weighs close to 2700 (if I remember correctly), but I thought he was a lot closer to 50/50.

[Itchief]

I was able to get in another 75 miles today which gives me about 150 miles with the rear sway bar and the more I drive the car the more I like the way it handles I think that I am getting close to having a very good set up

I think that I will go ahead with installing the front sway bar and see if it improves the way the car handles, I doubt it will help as much as the rear sway bar

Thanks again for all the support

Rick

[CraigS]

The 550/250 spring rates are one reason why the car is working better with the rear bar. I believe the FFR standard spring rates for a solid axle car are 500/350. You have a 300 lb difference between front and rear rates where the standard FFR only has a 150 lb difference. With your rear bar you have very likely brought the roll stiffness back closer to the FFR designed rates.

Agreed, but I personally don't care for the 350 rear springs as they make for a pretty stiff ride. The 250 springs plus bar is much nicer IMHO. Since the VPM bar adjusts from 60-225# it is really nice for dialing in the balance you want.

[mikeinatlanta]

Suspension science is fascinating. In an effort to keep weight to a minimum, I have heavy springs and a higher roll center. Very debatable but definitely the lightest combo so giving it a try. If I could ever finish the car we would learn how well it works. I have left room for bars if needed.

[NAZ]

What is your handling goal? What is your definition of "better" in regards to handling? What is your measure of goodness that indicates better or worse?

It's fun to make changes and see what happens and it's a learning experience. To get the most out of this experimentation you should first establish a well defined goal and a plan on how to accomplish that goal and a way too measure progress. Better handling is not a goal unless you can define what better handling is. That's why you will get different opinions and suggestions on your work as we all have our own idea of what "better" is.

And I would also suggest you spend the winter months reading up on suspension design and adjustments. Since you're working with springs now pay close attention to terms like motion ratio and spring frequency before you invest in another anti-roll bar (sway bar). While I don't know the motion ratio of your suspension the spring rate split F&R seems very extreme so you may want to focus on frequency and learn how that affects handling. You might even come away with a different POV on sway bars.

Good luck and have fun.

[Jeff Kleiner]

What is your handling goal? What is your definition of "better" in regards to handling? What is your measure of goodness that indicates better or worse?

It's fun to make changes and see what happens and it's a learning experience. To get the most out of this experimentation you should first establish a well defined goal and a plan on how to accomplish that goal and a way too measure progress. Better handling is not a goal unless you can define what better handling is. That's why you will get different opinions and suggestions on your work as we all have our own idea of what "better" is.

And I would also suggest you spend the winter months reading up on suspension design and adjustments. Since you're working with springs now pay close attention to terms like motion ratio and spring frequency before you invest in another anti-roll bar (sway bar). While I don't know the motion ratio of your suspension the spring rate split F&R seems very extreme so you may want to focus on frequency and learn how that affects handling. You might even come away with a different POV on sway bars.

Good luck and have fun.

Agreed! Although they play together don't confuse spring rate with wheel rate. Wheel rate is what is critical but how you archieve that is a function of the control arm dimenstion, the spring's distance from the arm's pivot and the spring mounting angle. Here is the calculator that I use:

Spring/wheel rate calculator

As you can see if you plug in some different numbers changing D1, D2 or the angle all affect actual wheel rate. For example the front of a non-pin drive front arm on our roadsters will result in:

D1 ~ 9.0"
D2 ~ 13.5"
Spring angle ~ 75 degrees

A 500# spring gives a wheel rate of approximately 157 pounds
A 750# spring gives a wheel rate of approximately 235 pounds

Change that spring angle to 45 degrees and look at what happens to wheel rate. Now change it to 90 degrees and see what the result is. These variables are why we see what seems like quite a difference between front and rear (or straight axle vs. IRS) with our cars while in reality after going through the calculations in the end the differences are not that large.

BTW, for anyone who is curious I run 750# front and 500# rear with a 3 link.

Jeff

[NAZ]

Thanks Jeff, but I couldn't get you link to work. I've never come across an online calculator so before I bought a wiz-bang suspension program to make all these calculations easier I wrote several spreadsheets worth of formulas to help me. If folks are interested in making their own spreadsheet calculator (the suspension software is rather expensive) Eibach has a good explanation of how to calculate several suspension parameters. Let's see if this link works: http://eibach.com/us/p-101-suspension-worksheet.html

[cgundermann]

Agreed! Although they play together don't confuse spring rate with wheel rate. Wheel rate is what is critical but how you archieve that is a function of the control arm dimenstion, the spring's distance from the arm's pivot and the spring mounting angle. Here is the calculator that I use:

Spring/wheel rate calculator

As you can see if you plug in some different numbers changing D1, D2 or the angle all affect actual wheel rate. For example the front of a non-pin drive front arm on our roadsters will result in:

D1 ~ 9.0"
D2 ~ 13.5"
Spring angle ~ 75 degrees

A 500# spring gives a wheel rate of approximately 157 pounds
A 750# spring gives a wheel rate of approximately 235 pounds

Change that spring angle to 45 degrees and look at what happens to wheel rate. Now change it to 90 degrees and see what the result is. These variables are why we see what seems like quite a difference between front and rear (or straight axle vs. IRS) with our cars while in reality after going through the calculations in the end the differences are not that large.

BTW, for anyone who is curious I run 750# front and 500# rear with a 3 link.

Jeff

And you don’t run any sway bars Jeff?

Chris

[GoDadGo]

While don't know if my car will be, loose or tight, but the VPN rear bar set up could be one heck of a suspension tuning equalizer once I know what I've got.
This thread I find to be extremely interesting since my set up yields a 50/50 front to rear ratio because my driveline is a bit further forward than for you Ford Fellows.
The fact that I added a 3/4" sway bar up front with custom mounts makes the VPM 3/4" rear sway bar something that looks very promising since the rates are adjustable.
Add in the fact that you could preload the right rear for Drag Strip Clutch Dumping Launches would be a big plus for this guy who's not a big fan the twisty race tracks.

[Itchief]

The one thing that I have learned while building this car is that there is always more to learn and to keep an open mind because other points of view may result in a better outcome

It looks like I need to spend some time this winter trying to get a better understanding of the cars suspension so I can better understand what I am trying to accomplish

My goal is to have a car that rides and handles very well and is a pleasure to drive, not so stiff that it is bone jarring or so soft that you cannot feel the road.

I will never race the car but I enjoy driving the two lane roads in the hills of southern West Virginia my favorite ride is from Fayetteville to Gauley Bridge to Ansted and back to Fayetteville. The road is cut into the side of the New River gorge with a lot of very sharp turns and a couple of 800 foot elevation changes and is a blast to drive

I am very close to having the suspension the way I would like it. The car launches very straight,handles very well in the turns but the front of the car wants to lean when I push through a sharp turn

Thanks for all the information and suggestions

Rick

[Joee]

And you don’t run any sway bars Jeff?

Chris

No he doesn't and neither do I my comment to the seat of your pants tuners, you are rolling the dice safety wise. I have been working on improving my cars drive ability for 5 years now, I make little changes and see how they play out in AutoX times. I also have a younger Co-driver at Pocono events to gauge true improvements. I reluctantly admit he bettered my raw time by a second this past season.

First your car needs to be balanced (scaled) after you decide on a spring rate. I currently run 700 front 400 ds and 350 ps rear FFR Konis. I have found these to be a good trade off for ride comfort, stiffer springs and stickier tires will yield faster times but, I dont like my teeth banging on the interstate bumps. The biggest improvement to our times and cars behavior was the addition of Gordon's control arms. My car is very neutral in 50+ mph slaloms and big sweepers. Now I have wiped out big time at a few events but it was in a controlled environment. I used to drive spirited and was lucky. Now I know what my car can and will do at speed and there is never a need to get there on public roads. These cars can be tuned to exceed most of our abilities and can handle at very high speed. Out of the box without using true tuning methods (Thanks to Mark Dougherty the Traveling builder and Gordon Levy for helping) you guys may be playing with fire.

[cgundermann]

No he doesn't and neither do I my comment to the seat of your pants tuners, you are rolling the dice safety wise. I have been working on improving my cars drive ability for 5 years now, I make little changes and see how they play out in AutoX times. I also have a younger Co-driver at Pocono events to gauge true improvements. I reluctantly admit he bettered my raw time by a second this past season.

First your car needs to be balanced (scaled) after you decide on a spring rate. I currently run 700 front 400 ds and 350 ps rear FFR Konis. I have found these to be a good trade off for ride comfort, stiffer springs and stickier tires will yield faster times but, I dont like my teeth banging on the interstate bumps. The biggest improvement to our times and cars behavior was the addition of Gordon's control arms. My car is very neutral in 50+ mph slaloms and big sweepers. Now I have wiped out big time at a few events but it was in a controlled environment. I used to drive spirited and was lucky. Now I know what my car can and will do at speed and there is never a need to get there on public roads. These cars can be tuned to exceed most of our abilities and can handle at very high speed. Out of the box without using true tuning methods (Thanks to Mark D Traveling builder) you guys may be playing with fire.

Thanks Joee, I have always tuned my Mustangs and upgraded to either Steeda or Maximim Motorsports thicker anti-sway bars. Found it interesting that FFR Cobras didn’t come with them for many, many years. I don’t have your tuning or racing experience and been following the different opinions on using them. It’s almost like the power steering and power brake debates. I have an older MK4 and just getting ready to graduate, so I don’t have many miles on her to gather an opinion. Right now, I don’t plan on adding them, unless something is readily apparent and agree with your stance - that for nothing more than spirited road driving, you would not notice sway bars if installed. I don’t plan on flogging mine near her limits.

Thanks for your perspective,

Chris

[RoadRacer]

I'll just throw in that although most hate push, it's lovely and safe for that first year in the seat of a new fast car!

My GTD40 was setup to push and saved my *** a few times as I learned the car. As I got faster, more miles and track time I changed spring and sway bar rates and dialed towards a (much faster) loose setup - way more fun, but I'm so glad I had worked up to it..

60,000 miles in that car, was wearing it like a second skin by then

[BEAR-AvHistory]

That's not surprising. Most manufacturers even those touting 50/50 weight distributions dial in some push to keep the customers safe

[Joee]

Right now, I don’t plan on adding them, unless something is readily apparent and agree with your stance - that for nothing more than spirited road driving, you would not notice sway bars if installed. I don’t plan on flogging mine near her limits.

Thanks for your perspective,
Chris

If you have a noticeable problem; then something in the assembly and setup of the suspension is wrong and sway bars aren't going to help. The biggest change to make for an FFR is having a full rod end and spherical bearing control arms. The poly ones if not thoroughly greased can act unpredictable. Also after 20k+ hard miles in different outdoor conditions some of the rear 3 link bushing can deform. These cars are great most don't take advantage of tire selection, pressure and road surface temps. I worked on that 3 yrs ago. The fix; re-balancing air pressure front to rear. Most run lower rear pressure for hole shot traction but in reality it contributes to push understeer. With tires hot on an 75+ deg surface I run 22psi front and 23 rear. ** Cold tires with too much pressure on cool Road surface (less than 50 deg) = Zero traction even with the best bars shocks whatever **

[cgundermann]

If you have a noticeable problem; then something in the assembly and setup of the suspension is wrong and sway bars aren't going to help. The biggest change to make for an FFR is having a full rod end and spherical bearing control arms. The poly ones if not thoroughly greased can act unpredictable. Also after 20k+ hard miles in different outdoor conditions some of the rear 3 link bushing can deform. These cars are great most don't take advantage of tire selection, pressure and road surface temps. I worked on that 3 yrs ago. The fix; re-balancing air pressure front to rear. Most run lower rear pressure for hole shot traction but in reality it contributes to push understeer. With tires hot on an 75+ deg surface I run 22psi front and 23 rear. ** Cold tires with too much pressure on cool Road surface (less than 50 deg) = Zero traction even with the best bars shocks whatever **

Thank you sir; great info!

Chris

[cgundermann]

That's not surprising. Most manufacturers even those touting 50/50 weight distributions dial in some push to keep the customers safe

YES, I have read that sooo many times. Keeps people honest...

Chris

[GoDadGo]

Measuring the spring compression and converting that to weight (redneck scale) my car weights about 2700 lbs with a full tank of fuel , 1700 lbs front and 1000 lbs rear that works out to about a 60/40 front/rear weight ratio

Rick

Rick,

Here Is An Easy "Swamp Land Method" For Figuring Out Your Front To Rear Ratio That Works Great:
If you don't have access to a fancy scaling system then you can get you a pretty good front to rear figures that will shock most shops with scaling tools.
I did it prior bringing my car to the alignment shop & place painters tape on each frame rail, which I then marked at 1" increments, with the centerline done in red.
Then I took my two floor jacks and lifted the car from both sides starting at the center point and thats when I was shocked to find I was close to a 50/50 front to rear bias.
I played with the jacks a few times moving them forward and aft and came back to the centerline marks each time.
Like you I've got a heavy engine since it is all iron, my transmission is a pig that tips the scales at about 180 "All In" and I'm running a Moser Dana 44 style 3 link rear.
The jack and painter tape method isn't high tech, but it will work as long as you get the car high enough so that all of the wheels are off the ground an inch two.
Just rember that when you use the Scales of Justice to figure this out to be careful, make sure the car stays level and watch your jacks to make sure they don't slip.
You just need some time, patience, a calculator if you don't feel like doing the math by hand, plus having a wife or pal to man the other jack is a plus too.

Steve

[Vette1972]

The one thing that I have learned while building this car is that there is always more to learn and to keep an open mind because other points of view may result in a better outcome

It looks like I need to spend some time this winter trying to get a better understanding of the cars suspension so I can better understand what I am trying to accomplish

My goal is to have a car that rides and handles very well and is a pleasure to drive, not so stiff that it is bone jarring or so soft that you cannot feel the road.

I will never race the car but I enjoy driving the two lane roads in the hills of southern West Virginia my favorite ride is from Fayetteville to Gauley Bridge to Ansted and back to Fayetteville. The road is cut into the side of the New River gorge with a lot of very sharp turns and a couple of 800 foot elevation changes and is a blast to drive

I am very close to having the suspension the way I would like it. The car launches very straight,handles very well in the turns but the front of the car wants to lean when I push through a sharp turn

Thanks for all the information and suggestions

Rick

Rick,

We drive the Vette and the Harley on the same road. We call that the "Magic Loop". Perfect for performance vehicles. Fun ride!

Len

[Joee]

Rick,

Here Is An Easy "Swamp Land Method" For Figuring Out Your Front To Rear Ratio That Works Great:
If you don't have access to a fancy scaling system then an easy can get you a pretty good front to rear figures that will shock most shops with scaling tools.
I did it prior bringing my car to the alignment shop by placing a piece of painters tape on each frame rail, which I marked at 1" increments, with the centerline done in red.
Then I took my two floor jacks and lifted the car from both sides starting at the center point and thats when I was shocked to find I was close to a 50/50 front to rear bias.
I played with the jacks a few times moving them forward and aft and came back to the centerline marks each time.
Like you I've got a heavy engine since it is all iron, my transmission is a pig that tips the scales at about 180 "All In" and I'm running a Moser Dana 44 style 3 link rear.
The jack and painter tape method isn't high tech, but it will work as long as you get the car high enough so that all of the wheels are off the ground an inch two.
Just rember that when you use the Scales of Justice to figure this out to be careful, make sure the car stays level and watch your jacks to make sure they don't slip.
You just need some time, patience, a calculator if you don't feel like doing the math by hand, plus having a wife or pal to man the other jack is a plus too.

Steve

The important number is not front to back as much as cross weight LF and RR compared to RF and LR. Working with these weights helps to eliminate any imbalance of a coil over being disproportionately jacked up relative to the others. Here is where I am at with 200lbs of ballast in driver seat and 1/2 tank of gas.

Front d/s 592 p/s 573
24% 23.2%
Ride height 4" 4"


Rear 702 605
28.4% 24.5%
Ride height 4.25 4.5

Total 1294lb + 1178lbs = 2472lbs

Cross weight: F d/s to R p/s 1197lbs
F p/s to R d/s 1275lbs
Total 2472 lbs

[cgundermann]

The important number is not front to back as much as cross weight LF and RR compared to RF and LR. Working with these weights helps to eliminate any imbalance of a coil over being disproportionately jacked up relative to the others. Here is where I am at with 200lbs of ballast in driver seat and 1/2 tank of gas.

Front d/s 592 p/s 573
24% 23.2%
Ride height 4" 4"


Rear 702 605
28.4% 24.5%
Ride height 4.25 4.5

Total 1294lb + 1178lbs = 2472lbs

Cross weight: F d/s to R p/s 1197lbs
F p/s to R d/s 1275lbs
Total 2472 lbs

Watched your videos Joe, man is your car is flat & neutral through the twisties! Nice driving...

Chris

[Joee]

Here is a shot making a turn in at about 40 mph at Pocono Infield AutoX

[cgundermann]

Great pic!

[GoDadGo]

Joee,

Are you running 275's up front with 315's out back?
I'm just wondering because that car of yours looks like it could also be used to flatten out asphalt since it appears to be Sporting Steam Rollers on all 4 Corners.

Steve

[Jeff Kleiner]

Here's one showing things a bit different than Joe's. It's a high speed right hand sweeper (I'd just come from where those cones are on the left). Hard on it turning right as can be seen by looking at how the LR tire is loaded under but actually showing some left countersteer on the front wheels. I had just changed rear springs in an effort to free up the back end and this photo showed me that it was just a bit loose like I was feeling...which was exactly what I was trying for!



Oh, yes, as Joe said no bars on my car either, just more spring rate and negative camber along with positive caster.

Jeff

RHsweeper.JPG

[Joee]

Joee,

Are you running 275's up front with 315's out back?
I'm just wondering because that car of yours looks like it could also be used to flatten out asphalt since it appears to be Sporting Steam Rollers on all 4 Corners.

Steve

295 A6's all around. This season I am going to try adding 315's to rear and keep 295's up front.

Full credit for my progress goes to my great friend and mentor Wade Chamberlin (RIP). He managed to run FTD at most events hes was in, that includes battling it out with shifter carts for FTD. He eventually ran 1000lb springs and 13" bias ply slicks all around. And no sway bars.

[GoDadGo]

Joee,

I'm looking at your best ET (12.14 @113) and video so I can't wait to get my engine back in and the car.

Your Car Making A Nice, Nice Pass:
https://youtu.be/OZUh5BcWWDg

My Last Drive Before Springing A Leak:
https://youtu.be/PCngiKoopkA

I'm hoping to get deep into the 11's with MPH between 120-125 MPH. (6,000 RPM In 4th)
Looking at your specs, I do think it will be possible.
Shown below are my driveline specs:

1. 383 Small Block Dart 9.7-1 Pump Gas Friendly Compression Ratio!
2. Eagle Internally Balanced Rotating Assembly With 6" H-Beam Rods With Floating Forged Flat Tops.
3. Dart Iron Eagle 215 CC Heads with 2.05 Intake & 1.60 Exhaust Valves.
4. Harland Sharp Roller Rockers & Other Go Fast Goodies.
5. Comp Cam Extreme Energy 288 Hydraulic Roller Tappet Cam
6. Edelbrock AVS 800 Feeding A Weiand 7530 Team G Single Plane Manifold.
7. Schoenfeld IMCA Modified Headers & They Really, Really Fit, But Stuff Had To Move A Bit!
8. New Old Stock Corvette ZF 6-Speed Transmission With Hydraulic Clutch. (.75 5th & .50 6th Gear Over Drives)
9. Standard Front End Set Up With Mustang Brakes & Forte’s .75” Sway Bar.
10. Standard 3 Link Moser TSD 500 Rear With 3.73 Gears & Explorer Brakes.
11. The wheelbase has been shortened by .875" to better center the rear wheels within the wheel arches and improve pinion angle adjustment.

Merry Christmas To All & Remember To Keep Christ In Christmas!

Steve

[Jeff Kleiner]

295 A6's all around. This season I am going to try adding 315's to rear and keep 295's up front.

Full credit for my progress goes to my great friend and mentor Wade Chamberlin (RIP). He managed to run FTD at most events hes was in, that includes battling it out with shifter carts for FTD. He eventually ran 1000lb springs and 13" bias ply slicks all around. And no sway bars.

Just thinking about (and missing) Wade this morning Joe. We had lots of talks and I got valuable coaching from him also. I reckon all of us who knew him will always miss him...

Dad,
Your goal should be easily attainable; my little ol' home built Trick Flow topped EFI 302 went 12.2s @ 118 with virtually no traction in 1st and much of 2nd (as indicated by the MPH vs ET). Your end should be well in excess of 100 HP over me

Merry Christmas guys!

Jeff

[Joee]

Jeff, me too especially when I am tweeking with one of his upgrade ideas and naturally the Pocono events, such a big loss.

Steve I agree with Jeff as far as your times. The challenge with our cars is getting most NHRA tracks that let you run that is the first step. To run you need fire jacket, arm restraints, new belts. Without a cage we aren't supposed to break 11. Tell tech you are a 12 sec car at about 110. Then run a few moderate runs, then hammer your last one or two bc they will prob tell you you are done in the high 10 low 11 sec line.