lift bar vs trac bar

what is the difference in the two? which if preferable for racing, and which is better for street?  

If I understand your question correctly - and there's a fair chance I don't, the difference is in their function.  A trac bar locates the rear end in the car laterally (side to side) and is also known as a panhard bar. Essentially what it does is to keep the rear springs or trailing arms from flexing from side to side during cornering.  It is also a close cousin to a watts linkage which performs the same function without some of the trac bars disadvantages.  The reason that I mention the watts linkage is that they are installed on current vintage Crown Victorias and may be available cheaply from a wreck.  If if is adjustable it can also be used to change the rear roll center.  I racing circles it is most commonly heard of in stock car racing and is the lower (rearward) adjustment hole in the back window on the right side.  I'm sure other types of racing except drag racing use them you just don't here about them so much.  As to your question about whether they are for the street or racing they are for anything where you would get hard cornering forces which includes most types of racing except drag racing and land speed record type racing.  

A lift bar is a traction device designed to reduce wheel-hop  and keep the pinion angle constant due to spring wrap-up during hard acceleration, also a close cousin to traction bars or slapper bars.  If you don't have a leaf spring rear suspension I'm not sure if they are applicable.  see:

http://www.mustangii.net/ssmfaq.asp

Again the answer to your question about racing or the street they are applicable drag racing for the most part although I can see an advantage to road racing if you have a leaf spring suspension.  Most stock car suspensions except for so-called street stock or bomber classes don't have any need for them as they don't use leaf spring suspensions.  Likewise with sports cars and road racing cars.

sorry, i should have stated that better. I meant a traction bar. they sell a lift bar and a traction bar. they look basically the same, so whats the difference?  

http://www.calvertracing.com/

Tremendous benefits can be realized when the CALTRACS traction bar system is installed on a leaf spring suspended automobile. CALTRACS traction bars were developed to achieve specific goals to improve high power traction while staying within hard set NHRA parameters.

Each of the two assemblies needed is comprised of three basic components:

1. 
   

   Front Pivot

   
   
2. 
   

   Force Transfer Link

   
   
3. 
   

   Rear Mount

The combination of these components changes the pushing point on the car by redirecting the turning action (spring wrap-up) of the rear axle through the Force Transfer Link into the Front Pivot. The Front Pivot Spring Stop Bolt resists this turning motion and also controls the bending of the leaf spring at its thinnest section. The push into the Front Pivot helps the cars weight shift towards the rear of the car because of a new directed angle of force toward the front of the vehicle. (The "Instant Center" moves farther forward). This is where the system emulates a Four link system. The pinion angle is also maintained. (See illustration)

1. The Front Pivot

Two steel plates sandwich the leaf spring sides. Two attach points in the plates provide the user with a selection in which the forward Force Transfer Link rod end can be located. A machined aluminum spring eye bushing and steel insert supports the front of the spring while allowing the plates to pivot. A spring stop bolt controls and restricts spring wrap-up. Spacers are provided for different vehicle applications that control clearances in the front spring eye pocket.

2. Force Transfer Link This is a length of chromolly tubing with CNC machined threaded inserts TIG welded into each end. The front Insert is machined with right hand Threads and a HEX outer shape for Simple wrench adjustment of the Installed assembly. The rear insert is Left hand threaded. Opposite thread Styles at each end provide the means to easily lengthen or shorten the link for desired pre-load adjustment.

3. Rear Mount

A welded ¼" steel assembly replaces the original vehicles spring perch and incorporates the mounting provisions for the rear rod end of the Force Transfer Link.

I'll take a crack at this.....

First off, we're talking about a leaf spring car here, right?  If so....

I've used "traction bars" on leaf spring cars many times.  They are often referred to as a "slapper bar" becuase the tip of the arm "slaps" into the front spring eye when the axle is loaded up heavily- a hard launch.  A leaf spring tries to twist under heavy loads into the shape of an "S" as the pinion tries to point upwards (opposite direction of tire rotation).  This is bad bad bad for traction as massive wheel hop usually ensues as the rear end alternately twists up and releases.  The slapper bar puts a limit on this twisting (adjusted by the gap betewen the front snubber and the spring eye- usually about 1") and uses any remaining force left over to shove the axle straight into the ground.  For a cheap bolt-on that's been around since the 60s (maybe earlier??) it ain't bad, if properly adjusted.  Note, the traction bar does NOTHING to push the car forward- it ONLY limits axle wrap-up.  The forward-pushing force of the axle is still carried entirely by the front half of the leaf spring.

The Traction Bar is a different can of snakes.  Designs vary, so it's hard to cover every possible version, but suffice it to say, they are designed to prevent axle wrap-up (either completely, or with some "give") similar to a traction bar BUT the key difference is that they ALSO carry the force of the axle pushing forward as well.  They actually become a locating link in the suspension system.  A more sophisticated device.

Which is better?  Man, I've run slapper bars on lots of cars and I don't really have much bad to say about them.  Suspension works pretty much like stock under normal driving conditions but has some "bite" to it when you launch hard against sticky tires.  I've heard of guys runnings 8s on slapper bars, although I've never come anywhere close to that.  Traction bars are a relative unknown to me, especially since leaf spring performance cars haven't existed in almost 30 years.  However, I'm building up a 1990 Chevy 454SS pickup right now with leaf springs and a set of Competition Engineering Slide-a-Link bars (traction bars) are on the shopping list this time around!

ok, so a lift bar does alot of nothin compared to traction bars. sounds great. I also had an old racer tell me about a suspension system he set up. Basically you took your leaf spring, jacked the rear end up untill it bowed the other way, then some how held it in basically that form. then when you lauched it had more snap and would fling the car slightly forward and up. anyone know what he meant?  

ok, so a lift bar does alot of nothin compared to traction bars. sounds great. I also had an old racer tell me about a suspension system he set up. Basically you took your leaf spring, jacked the rear end up untill it bowed the other way, then some how held it in basically that form. then when you lauched it had more snap and would fling the car slightly forward and up. anyone know what he meant?

He de-ark the spring. I is mostly use to lower a car. Hemi Dart Springs are popular for Novas, you get them in a Mopar parts book.

Traction Bar-Usually bolts on to a suspension to aid the leaf spring to lift the car buy making a solid bar from the rear axel mount to the front of the leaf. Keeps leaf spring from wraping up.

Lift bar-Usually welds on directly to the rear end, works like the bottom of a ladder bar, and bolts to the floor of the car to help lift the front end up. Usually longer than traction bars to get more leverage to do the same job. You usually have to make these bars out of 2x3 square tubing.

Ladder bar-Usually welds on the rear end and mounts on top and bottom of a rear end and meets at a point were it bolts on to a car. Leaf spring floaters must be used to prevent spring bind. Usually shorter than lift bars but longer than traction bars to do the same job.

South Side Machine sold lift bars, but I don't know if they are still in busness.

I tend to discount marketing hype from the manufacturers when wanting the facts about stuff.  Too much of it tends to remind me of that Oxy-Clean guy, lol.

So I usually talk to the guys that actually run it.  For straight line racing both types show an improvement in traction.  But no one I've talked to has any data for traction changes in a turn, for better or worse.  Since I prefer handlers that is a concern of mine.

One thing that you haven't mention that does help both types of handling is leaf spring clamps.  If you look at your current spring pack you will see a few clamps near the tips of indiviual spring leafs.  What you do is buy some more and clamp each leaf segment forward of the axle.  Nice thing about this method is threefold.  It's cheap, it's tuneable ( more segments clamped means a stiffer front segment) and it works.  You also do not have funky handling issues you might have with the other styles that may engage one side only in a spirited turn. 

Steve

I tend to discount marketing hype from the manufacturers when wanting the facts about stuff.  Too much of it tends to remind me of that Oxy-Clean guy, lol.

Who are you talking to and what are you talking about?

Hemi Dart Springs are popular for Novas, you get them in a Mopar parts book.

Traction Bar-Usually bolts on to a suspension to aid the leaf spring to lift the car buy making a solid bar from the rear axel mount to the front of the leaf. Keeps leaf spring from wraping up.

Lift bar-Usually welds on directly to the rear end, works like the bottom of a ladder bar, and bolts to the floor of the car to help lift the front end up. Usually longer than traction bars to get more leverage to do the same job. You usually have to make these bars out of 2x3 square tubing.

Ladder bar-Usually welds on the rear end and mounts on top and bottom of a rear end and meets at a point were it bolts on to a car. Leaf spring floaters must be used to prevent spring bind. Usually shorter than lift bars but longer than traction bars to do the same job.

I have used all mentioned and currently have:

Hemi Dart Springs on my 69 Camaro now, they are my favorite.

Lift Bars on my V8 Vega and tubbed V8 LUV truck

Traction Bars with J bolts on my 68 Camaro

Ladder bars are on another 69 and 68 Camaro (I have 2 69 and 2 68 Camaros, along with 4 Vegas, 2 Luv Trucks, 70 Camaro and 78 Camaro)

Cal Tracs on my buddies Camaro.

I'm talking about the cut and paste someone done from the Cal-Tracs website.

Steve

Does that mean Cal-Tracks aren't good?? I always thought they were.

Phil

No, it means I have no information regarding their performance in any racing aspect other than straight line racing.

I do not know how they perform in corners, especially in spirited use.  They may work great, have no effect or they could be twitchy as all get out, I don't know.  However, anything that changes the spring rate based on axle wrap up would make me concerned without more information.

Steve