Hollow or Solid Sway Bar

[JRouche]

I use a hollow bar up front and at the rear. Straight bar with splined ends, and solid arms.

These.... http://www.1speedway.com/standard_swaybars.htm

A few benefits and some drawbacks.

The benefits.....

One being able to tune it without much extra cost. Changing the rate can be done to a small degree by changing the location of the mounting holes on the arms. Same with some solid or hollow aftermarket bars but maybe with a lil more control.

The arms come undrilled. So you can place the holes anywhere on the arm as long as you take into concerderation the links and their angles. You dont want a sever angle on the links. Longer links will afford more fore and aft locations on the arm while still keeping the links closer to 90* of the arms. If the packaging of the suspension only allows you to have very short links then the placement of the mounting holes on the arms becomes very limited.

But the low cost of tuning with a straight bar really comes from the low cost of the torsion bars. They are 90 bucks. And really, they are the standard if bought from speedway. You will see their bars relabeled under other dealers names. They make some good bars.

So to change rates its just a matter of determining if you need more or less. And thats a crap shoot for the most part, until you drive the car. With any ones bars. Unless you are building an exact car that the testers used to show performance most of us are just shooting in the wind.

But I imagine many guys are just looking for a bar that they can buy and it will fit. As busy as most suspensions are there really isn't alot of room to put a sway bar in, specially if one wasnt there to begin with.

And that leads me to the downfalls of the straight torsion bar sway bar. Packaging.

I thought I had a bear of a time finding room and making the mounts for my rear bar. But it fit and I didnt have any clearance issues in the end.

But hang on now. To put a straight bar in the front was almost not doable. Now I know why stock or aftermarket bars look like limp spaghetti, all bent around in many variations. You have to wind around ALOT of other components. It was a nightmare. But I got her in with a decent 3/8", oh, ok, more like a 1/4" clearance from ALL of the other cars structures. Full travel and Im not hitting. Took some and work. But the straight hollow 1-1/4" bar fits.

But anyway. Back to zbadone's post. Hollow or solid.

I really dont see a reason for using a solid bar UNLESS its for packaging. A solid bar of the same diameter will give you more spring rate. And yes, it will come with more weight, but unless you are racing and looking at ALL of your weights then thats a moot point.

BUT!! only if packaging wont allow you to fit a fatter hollow bar in place of a heavier slimmer solid bar of the same rate. If you have the clearance for a larger diameter hollow bar then you should use it.

Its about effieciency. A hollow bar is more efficient if sizing is not an issue. If sizing is taken into the consideration, for say a very tight packing on the front end then the efficiency scale is narrowed some. The weight for spring rate might be pushed aside some for the packaging needs.

But to be honest, those fitments are far and few. Usually the spring rate compared to the physical weight is gonna be the deciding factor. And a hollow bar has an edge over a solid bar if packaging is taken out of the equation.

Why, well, like some of the other guys have said. The core of a bar of spring doesnt do much for any of the spring rate. Its just dead weight.

So why does a bar thats a solid 1-1/4" have more rate than a hollow bar of the same diameter with a 1/4" wall have more spring rate? Because the 3/4" core does still have some rate to it. It would be like having a 3/4" solid bar inside of the hollow 1-1/4" hollow bar. But the last say 1/2" of that core doesnt have much rate to it. It diminishes very quickly. The center section of the solid 1-1/4" bar, the half an inch solid section doesnt have much spring rate at all. Its just along for the ride.

But a slim 1" solid bar will be very close, maybe 50lbs (lower) of spring rate, to a larger hollow bar that has an outside diameter of 1-1/4" and a wall thickness of .095" (around 3/32",, pretty thin). But the hollow bar will be alot lighter still. And still have more spring rate.

So???? Hollow bar YES!! If you can fit one in. Sooooo much lighter than a solid bar for a given spring rate. IMO anyway, and Im just regurgitating what I have read and learned. I dont have any engineering knowledge. JR

[wmhjr]

So lighter wheels and reduced roll resistance only help a drag car??? As Norm said the physics are the same. I guess why the F1 guys use steel wheels and steel bolt no lightweight titanium stuff.

No, that's not what I said. What I DID say is that you can't assume that because it does or does not help with a drag car then it will or will not improve an autox car. The physics are DIFFERENT! And the location of weight, the distribution of weight and the EFFECTS of that weight result in very different characteristics between the two disciplines. At a very (and I mean VERY high level) there are similarities. Higher HP/weight ratio is better (assuming you maintain traction). Beyond that, the METHODS you choose to optimize performance are incredibly different. I honestly can't imagine anybody with any experience whatsoever not getting that.

I'll agree there are different optimal chassis settings for strictly straight line vs corners. But again some is theory. As I said general drag theory get rid of the front sway bar for weight and to let the front end lift for weight transfer-my car ran identical times. Open headers/no exhaust system should go faster than adding an 80 lb system-my car ran identical 1/8 mile times.

Yes there are some differences -drag cars generally do better with a taller sidewal to absorb some of the shock and not blow the tires away. Why many of the street/strip LS guys I know hook better with a taller sticky DOT even a 275/60/15 than a 275/50/17.

There are "some" differences? You're kidding, right? Serious question - have you ever built a road race car or worked on one? I don't mean that as an insult - a real question. My drag cars were frankly worthless to drive as just a normal street car much less an autox car. My best cars would launch on rails and were very consistent, but wallowed around corners like Barney the purple elephant drunk on bourbon. It's not theory - it's science. You can even look at the FAST guys to see what they do with chassis stuff just to go faster within their class. Amazing.

I'll It is generally a little easier to quantitate strictly weight changes on a drag car
.

Nope. Only for quantifying weight differences as they impact STRAIGHT LINE PERFORMANCE. Show me a NASCAR or SCCA team that uses 1/4 mile times to make changes to their cars. Just one.

I still go back to my original contention if you put the majority of In an autoX or open road course the longer time and course has more variables in driver(take a different line in a turn, brake at a different point etc etc) that can change lap time. vs adding 50 lbs. Most 11-13 second drag cars 100lbs is generally .1 seconds/1mph. I would bet on an autoX car that would be tough to measure.

folks here on a road or autoX course. Pull 8lbs, shoot I'd bet even 40 lbs, off the nose it would be hard to quantitate back to back run differences. I woud bet though lighter wheels with road race slicks they would go faster than heavy wheels and DOTs.

I don't disagree that most drivers here may not be consistent enough to be able to quantify weight changes reliably. But THAT'S NOT THE POINT. The point isn't what the driver can do, it's what the CAR can do - that helps the driver. If you're building a car, build it right considering the boundaries of your purpose and your budget. Don't just ignore obvious performance enhancements because you're not sure you will see the benefits of each individual part - remember the collective. This whole thread is ridiculous. There is certainly merit to the discussion of whether tubular can meet the same performance characteristics of solid. But assuming it can from the particular application point of view (ie, handling the relationship between chassis and lower control arms) then the only question is how much a difference, and how much is the cost. And, if you're already going to replace the bar anyway, there is simply no logical discussion whatsoever.

BTW, how about you find me that drag racing Busa with extended rear swingarm that's road racing? That would be a great video

[Skip Fix]

Most of us probably wouldn't notice, and haven't picked all the low-hanging fruit anyway. Exactly! And I'd bet juggling tire pressures might pick you up as much time.

Yes I've worked on road race and autocross cars. My TA was autocrossed for 15 years-stock and CP(cam change at that time was not allowed in ESP where it would have fit).SCCA member for 20 years.

And yes the physics is different. My point on the weight is on a drag car the driver variable is not as much as a road/autoX. So there is a direct correlation between weight and times generally. As I said before go do a run, then pull out 8 lbs but brake slightly different spot was the lap time different because of the weight or because of the different braking is what I am saying. And yes I know the NASCAR boys don't use a 1/4 mile to tell if their weight reduction made them go faster. But since even at the same weight juggling wedge, stagger(yes I've been around circle track guys too-got a late model car sitting in the garage) all can make bigger impacts in their lap times than an 8 lb weight change(a little more than 1 gal in the tank)-my entire point in this discussion and that IS on a scienced out professional combination-different lap times same weight different chassis settings. Since unless you fill up during laps, race at the exact same gas tank fill you can make an 8lbs weight change during a race! How many guys exactly fill up their tank to autoX-especially if they drive to the event?

Again a wider tire different tread compounds do have different rolling resistance and can impact times if you over do it. Again something easily quantitated on a drag car and theory IS used in going around corners. A taller tire or one out of the wheel well can affect aerodynamics esp on formula cars. As Norm stated most of our cars unless they are tubbed or a tube frame that will not be as much a factor. Most class racing have specs for tire sizes.

Also Norm I would bet most of those cars winning jackets have enough lap times to dial in the car for it's class and current chassis setup and the variable in lap times is driver.

Since weather can significantly impact HP on the same engine even on the same day we'll leave that out of the discussion for lap time comparisons.

And yes my car when switched to drag only no front bar, loose convertor etc etc wasn't much for cornering. But actually even the drag times improved putting my tighter Guldstrand/Bilstein road race shocks back on it So much for 90/10s and rapid weight transfer being the ticket! Now a 22lb front sway bar and road race shocks are on it and same improved times.We get back into theory vs track results. Why did a drag car get faster with tight shocks and not get slower adding a 22 lb weight out on the nose that also slows front end travel? Only difference now from it's CP suspension days are front and rear springs.

And no weight distribution being balance helps both type cars. More weight off the front and balanced toward the rear helps drag traction also.

[silver69camaro]

"BUT, every manufacturer will bump the OD up 1/8" or so to compensate for the lack of inner material." I would bet though most folks brains are assuming that the hollow since it is "bigger" by 1/8 would act like a bigger solid bar. So they buy a bar that is bigger but get comparible stiffness to the smaller solid bar. So did the car handle better or they get the placebo effect from "bigger is better"?

I give up!

[Skip Fix]

Matt I'll agree if a hollow bar gives me the same feel and track performance as the solid I'll use it to shed a few pounds. I'll agree a knowledgeable guy will buy it for all the same reasons listed here.Most of the guys here would probably fall in that category.

I'm just saying that your average Joe car guy buys for "bigger is better". Why lots of motors are over cammed,over carbed etc etc.A common concept we all see. It also relates to their suspension choices. Did they buy the slightly bigger hollow bar that as was said has the same stiffness as the smaller solid bar to save the weight to go faster because they are lighter and not the rigidity/flex or do they buy it because it is listed as bigger and that is what they though they needed to go with that Victor intake with an 850 DP on a 350 with a 250@ 0.050 cam with 2" headers to drive on the street and wonder why his power brakes don't work.

[JRouche]

I'm just saying that your average Joe car guy buys for "bigger is better". Why lots of motors are over cammed,over carbed etc etc.A common concept we all see. It also relates to their suspension choices. Did they buy the slightly bigger hollow bar that as was said has the same stiffness as the smaller solid bar to save the weight to go faster because they are lighter and not the rigidity/flex or do they buy it because it is listed as bigger

I have to agree with you somewhat with this. And I have to blame the aftermarket dealers and manufactures.

A guy wanting to improve his car re: the suspension, and more to the point, the sway bar, anti-roll bar or what ever the term is used is relying on the dealer or manufacture to supply some info on the bar. THEY DONT!! They give sizing specs and thats all. I dont EVER see spring rates associated with aftermarket bars.

So hell, whats a guy to do but guess or take the dealers opinion. And all the dealer has to offer is the size of the bar. Well what the heck does that mean. Nothing at all. It just means the dealer is saying the bar is "this" large and will increase the performance. HOGWASH!!!

All they are saying is its a larger bar and should give you more roll control. So YEAH, why wouldnt a guy think a larger bar is in his best interest. Even if he (and the dealer) doesnt know exactly what the amount of spring rate for that bar is.

So yeah, the dealers and manufactures make sure to put a certain spring rate for the suspension springs we buy. But hell no. No way to nail down a certain spring rate for a roll bar.

So they sell it as bigger is better. Thats so stupid. Ummm, thats why I went with a straight bar. I know what my spring rates are, anyone else with a one piece bar know the spring rate of yer bar??? I have yet to see any published spring rates for a one piece roll bar. And I have looked. Not found yet. They always SELL by size. Just looking to make some money is what I see. JR

[wmhjr]

I'm just saying that your average Joe car guy buys for "bigger is better". Why lots of motors are over cammed,over carbed etc etc.A common concept we all see. It also relates to their suspension choices. Did they buy the slightly bigger hollow bar that as was said has the same stiffness as the smaller solid bar to save the weight to go faster because they are lighter and not the rigidity/flex or do they buy it because it is listed as bigger and that is what they though they needed to go with that Victor intake with an 850 DP on a 350 with a 250@ 0.050 cam with 2" headers to drive on the street and wonder why his power brakes don't work.

So what? The point you've been seeminly trying to make is that the tubular bar is a waste of money because of your 1/4 mile "test" (which again, I personally think provides no value - JMHO). So you're also saying the bigger cam, the 850DP, etc are also wastes of time and money?

I guess we're on two different viewpoints here. I agree completely that uneducated people buy stuff that won't help them or will actually hurt them because they haven't done their homework. OTOH, that doesn't make the part "dumb" or "useless". My .660 lift roller cam sure isn't "too big" for my motor. It would be on a 8.5:1 1975 stock motor. Not on mine.

I'll say it again and maybe it'll start to stick. The OP was asking a question and trying to do his homework. On its own merits, a tubular sway bar may not make a measurable difference. As part of a "total build" it may be the right part. It all depends on all the OTHER things you're doing. A cake is not measured by one ingredient. Its quality is measured by the combination of ALL ingredients and processes.

[Norm Peterson]

And yes the physics is different

The physics is not different; it's the details of how you apply it that are. There's a difference.

How many guys exactly fill up their tank to autoX-especially if they drive to the event?

Quite a few autocrossers will run with the minimum amount of fuel that does not result in loss of fuel pickup. I've found out where less than minimum was in the Malibu, and I've heard when others have tried to save a little too much fuel weight . . . and this is at the regional level, no less.

Also Norm I would bet most of those cars winning jackets have enough lap times to dial in the car for it's class and current chassis setup and the variable in lap times is driver.

Autocross at that level is three shots to learn the course, starting from square one where all anyone has is a few course walks. So I suspect that the variable is more about how well a given driver can learn a given course. You still can't be leaving any 0.040's on the table.

And yes my car when switched to drag only no front bar, loose convertor etc etc wasn't much for cornering. But actually even the drag times improved putting my tighter Guldstrand/Bilstein road race shocks back on it So much for 90/10s and rapid weight transfer being the ticket! Now a 22lb front sway bar and road race shocks are on it and same improved times.We get back into theory vs track results. Why did a drag car get faster with tight shocks and not get slower adding a 22 lb weight out on the nose that also slows front end travel? Only difference now from it's CP suspension days are front and rear springs.

Perhaps there is such things as optimum damping and optimum balance between bump and rebound even for drag racing . . .

As far as the front sta-bar vs rate of nose rise goes, the bigger reason for removing a front bar almost certainly has more to do with shifting the roll couple rearward than it does on allowing more or quicker nose rise. When the roll stiffness is mostly out back, engine torque reaction is mainly reacted in a fashion that re-plants the RR tire instead of also trying to load the RF. And more equal tire loading means greater total forward bite even with a posi, a locker, or even a spool (they just keep the wheel with less forward bite from falling off into purely sliding grip until the other side also does).

That the LF will rise more/more rapidly is the unavoidable consequence of allowing more total chassis roll rather than something actively sought for primary benefit.

Chassis torsional stiffness matters, with a torsionally stiff chassis being beneficial (your CP build may be mitigating the presence of a front bar more than a stocker or a purpose-built dragstrip chassis would).

I doubt you'll find many drag racers who think in such corner-carving terms as roll stiffness and its distribution or chassis torsional stiffness, but I can't see this situation being anything else.


Norm

[Skip Fix]

"On its own merits, a tubular sway bar may not make a measurable difference. As part of a "total build" it may be the right part."

We agree here! But is IS advertised as being better. Maybe it works as part of a package but is the one piece definitely better than what it is replacing?

The other main point maybe I wasn't making well that JRouche touched on does relate to this discussion and solid over hollow is the advertising by the suspension(or intake or carb folks). They are marketing their bar as "bigger" to the general public that might need a bigger bar and that hollow is as stiff as solid and "will" handle better when it may or may not handle any different. Any independent verification?? Edelbrock swore to me on the phone their Pontiac performer(before the RPM was out) would out perform a "factory"intake even a RAIV or HO. It is advertised as such besides what their tech spouts. On my RAIV heads it KILLED airflow by 10% over an HO intake-wouldn't have made the motor perform better than a factory intake.

Does a plain Baer brake system with the same size rotors work better than a factory single piston with a larger pad surface area? They sure have advertised they do, or a Wilwood smaller rotor smaller pad Dynalite system on a 3600lb car?

Unfortunately in our hobby there are not "peer reviewed" testing as in medical,scientific or engineering fields. The magazines doing them take ad money which often influences results-even most medical lecturers now have to disclose if they do studies for the drug companies and have a conflict of interest in the results. My machinist built a motor for one of the big magazines-somehow once in print many of the components got changed to bigger advertisers products for the build. So I guess I'm just a skeptic when it comes to auto advertising, even if it is actually a better product. Kind of like racing a flow bench or dyno numbers-what does it do at the track is the real deal.

Norm on my car and the sway bar and shocks for drag-drag shocks let the front end lift and transfer weight too quickly. It would hook then drop the front end and unload the rear tires. Slower weight transfer allowed to to stay hooked. Something the Pontiac guru Jim Hand even found on his 11 second wagon,tighter shocks worked better. Also the "new" thing for drag cars is adding a rear "anti roll bar" to help them go straighter. Alot like a sway bar! Also many drag guys have found the rigidity of their chassis can help consistency, not to the extent a roundy round corner carver of course.

"So I suspect that the variable is more about how well a given driver can learn a given course." I agree but still a mistake or change in braking point/accelerating point on the course would change the times more than a 8lb difference in weight on that same car. On a road course where there is less rapid changes in inertia once you are at speed and a longer lap time I would bet that 8 lbs difference would be even less per lap, and the gas used during that lap could sure change 8 lbs, I know one drag pass can do it from rolling across the scales myself regularly.

So do a "double blind study" using a solid vs hollow bar-same end links and bushing durometer hardness and then I can go for it

[Norm Peterson]

Also the "new" thing for drag cars is adding a rear "anti roll bar" to help them go straighter. Alot like a sway bar!

It IS a rear sta-bar ("sway bar"), just sold under a slightly different but entirely accurate name. And it does the same thing, shifting the roll stiffness distribution. If your unmodified car roll stiffness is distributed 80% front/20% rear and you want something like 40%/60% you can either throw away front stiffness (smaller or no bar), add rear stiffness (add big bar), or even do both. I imagine that there are limits to what you can do with just the bars or would even want to, but that's the idea.


I think we have to agree to drop consideration of driver errors from this discussion. Sure, it affects the results more - miss a 2-3 upshift or screw up and early-apex a corner and run out of pavement on track out might be "worth" several hundred or a thousand lbs added to a properly driven car. Or a wreck if you find a wall or a catch fence. But as near as I can tell, . . . . the likelihood of making such errors isn't a function of making any of these small mods. So either the driver is good enough to never make them or is unskilled enough and always does; the errors just can't come in a pattern that favors the outcome of either arrangement over the other.


Norm

[wmhjr]

What you're talking about exists everywhere, and not just in our hobby. My problem with your position on this is that you're targeting tubular sway bars, but I don't see you making the same claims about tires, wheels, frankly every single product on your car. At some point you have to do your homework, talk to people who work with this stuff, and make a decision. If everyone waited until there was "scientific proof" in some sort of "double blind study" - we would frankly have no options to even consider.

If you read carefully my position from the beginning, it's quite clear. There are things I used in my build that I KNOW work. Some of that was tested on a dyno, and I also had the advantage of up front data from engine builders, etc who have proven concepts and combinations. Some things were more a leap of faith based on perceived expertise and experience from people like Marcus at SC&C, Frank at Prodigy and others. So far, am I confident that my choices are the absolute "best" combination? Heck no - I have no idea. Am I confident that they are "good" solutions that have been proven to work? Heck yeah!

Just because you cannot measure the difference one part makes by itself does NOT mean it is OR is not a "better product". And again - I absolutely do NOT agree that testing on a drag strip necessarily correlates to anything on a road course. Not going to change my mind there. Been down TOO many passes to start believing that.

Back to the topic at hand. The OP didn't just go out and buy something based on some magazine add. The OP asked a question here - far from just believing marketing hype. There is certainly some question as to the performance of tubular vs solid. People here who seem to know what they're talking about weighed in. I wish some others had also done so. I would also agree that tubular or solid, a straight splined bar would allow for the best calibration and testing. I should also be up front that I'm not a Jim Hand disciple. He's another guy - not a god. There are things that many people including myself don't necessarily agree with. His book is good. And outdated. If I want to measure changes for a drag car, I'll do test and tunes at a strip. If I want to measure changes for a road car, I think I actually need to turn the wheel in at least one direction

[wmhjr]

I think we have to agree to drop consideration of driver errors from this discussion. Sure, it affects the results more - miss a 2-3 upshift or screw up and early-apex a corner and run out of pavement on track out might be "worth" several hundred or a thousand lbs added to a properly driven car. Or a wreck if you find a wall or a catch fence. But as near as I can tell, . . . . the likelihood of making such errors isn't a function of making any of these small mods. So either the driver is good enough to never make them or unskilled enough and always does; the errors just can't come in a pattern that favors the outcome of one arrangement over the other.

Norm

So Norm, would you also agree with the following as to why driver errors or variation should be removed?

It's just like target shooting. In bullseye pistol shooting I've got a .45 that has been bench tested and proven to shoot 1.5" groups at 50 yards. Now, I KNOW I can't shoot 1.5" groups. The biggest improvements in my scores will be the result of better technique. BUT - since it's all about consistency and predictability, having a TOOL that performs at a higher level reduces variation (and therefore the probability of error) just a little bit more, giving me a greater chance of an optimal result. If I'm shooting like crap, that 1.5" pistol capability won't be able to be measured during a match. BUT - if I happen to shoot really well, my chances are better. BTW, I still don't shoot well enough.

Road cars are the same way. A crappy, overweight and inexperienced driver can do a terrible job even in a top notch prepared race car. But without considering budget, every little advantage you build in increases your potential just a little bit more.

Make sense?

[Skip Fix]

"I don't see you making the same claims about tires, wheels, frankly every single product on your car. At some point you have to do your homework, talk to people who work with this stuff, and make a decision."

I did make the same claim if you looked at my post about more carb, more cam. Why I and lots of racers have shelf full of carbs, cams, headers, mufflers,springs, shocks, convertors, rear gears, tires that have been tried for my conversation. Nitto drag DOTs sure don't stick like M/T just at the top of the list I recently swapped out. I DO buy and personally try lots of products and freely will tell what helped or hurt my combination. My current pump gas motor in my TA got over 20 pulls. 3 carbs, 2 intakes, three different rocker ratios,timing settings. I've had Guldstrand, Herb Adams, Global West parts on the TA back when you could pick it from Adams place in Monterrey. Heck I autocrossed a 1" rear Adams bar with a stock front bar and did fairly well but LOTS of parts in my garage,attic,storage spaces,on multiple cars(my kids high school driver 81 TA was built from spare parts) etc. that were actually tried.


So lets get back to the original question then-even on a well tuned car NO other changes, same driver, same good line around the track,tires, bushing hardness etc etc --will a 1 1/4 hollow bar give faster lap times or noticeable better handling than a 1 1/8 solid bar(since it was mentioned that generally they increase on a 2.5 mile road course or typical moderate length autoX course for the majority of cars and drivers? And we know that because it was actually done and compared how many times?

It seems you guys are not just implying but saying it will make a difference on the clocks and the seat of the pants. That is my skeptical nature in this discussion as I've swapped enough parts and enough track time to doubt that more than 1% of us would feel or measure that improvement even if the bars actually have the exact same rate(something still not shown comparing one bar to a different one). But then who would have guessed a fresh better tranny and a new looser convertor would have picked my drag car up almost 0.7 seconds!

"It IS a rear sta-bar ("sway bar"), just sold under a slightly different but entirely accurate name. And it does the same thing, shifting the roll stiffness distribution." You and I know that but the drag guys say its different

[JRouche]

Road cars are the same way. A crappy, overweight and inexperienced driver can do a terrible job even in a top notch prepared race car.

Come on now. Just cause a guy is fat and overweight. Im 5'8" and 160 so, not fat. But give the fat dude a chance. Oh, and my rule. NO FAT chicks. LOL

No, no!!! I know that was just a typo right? You were thinking of the car and started writing about the driver. I get it. Im just trying to humor up the post a lil You WERE talking about the overweight car right, not the driver? LOL Never know.

My take? I think all of you guys have some solid points and are knowledgeable when it comes to cars. Sometimes the waters can get muddied up a lil though with differing ways of talking about similar points of view. In the end you folks might actually get to the same point but on different roads.

Kinda cool. I like to get all the opinions from several folks. Pick out the bits and pieces that are common and a guy like myself, or the OP can get a good understanding of whats involved.

Its good chatter and thanks for sharing your opinions. We all learned something. I did anyway. JR

[Norm Peterson]

So lets get back to the original question then-even on a well tuned car NO other changes, same driver, same good line around the track,tires, bushing hardness etc etc --will a 1 1/4 hollow bar give faster lap times or noticeable better handling than a 1 1/8 solid bar(since it was mentioned that generally they increase on a 2.5 mile road course or typical moderate length autoX course for the majority of cars and drivers? And we know that because it was actually done and compared how many times?

It seems you guys are not just implying but saying it will make a difference on the clocks and the seat of the pants. That is my skeptical nature in this discussion as I've swapped enough parts and enough track time to doubt that more than 1% of us would feel or measure that improvement even if the bars actually have the exact same rate(something still not shown comparing one bar to a different one).

The advantage is really there, or at least is potentially there. Whether a given driver takes full advantage of it on any particular run or lap is a separate question.

But then who would have guessed a fresh better tranny and a new looser convertor would have picked my drag car up almost 0.7 seconds!

Depending on what was in there before (OE or mild street/strip?), it's not hard to guess that there would have been improvement. If you know enough about the two torque converters involved and the engine's torque curve, you can estimate the effect on rear wheel torque and hence acceleration. Do this for every mph of speed increase enough times and you'll have an estimated effect on ET (and mph).

"It IS a rear sta-bar ("sway bar"), just sold under a slightly different but entirely accurate name. And it does the same thing, shifting the roll stiffness distribution." You and I know that but the drag guys say its different

Yeah, it's kind of hard to get lots of folks with the straight line mentality to see any connection between what they're tweaking to go straight better and what some of the rest of us do to turn corners better. I've met exactly one drag racer who understood this particular topic well enough to realize why you don't need a rear antiroll bar with ladder bars.


Norm

[Norm Peterson]

So Norm, would you also agree with the following as to why driver errors or variation should be removed?

Make sense?

I think so. At a level corresponding to banging away at tin cans and bottles, mechanical excellence hardly matters. Every round is either a hit or a miss - if anybody is even bothering to "keep score". Consistently closer groups doesn't even figure in, since missing by 1/4" might as well be by a foot or more.

At a more serious level, the better tool starts to have influence on the results. There's got to be a bit of "picking yourself up by the bootstraps" going on unless you're also receiving instruction and guidance. Maybe even if you are.


Norm

[Skip Fix]

The advantage is really there, or at least is potentially there. Whether a given driver takes full advantage of it on any particular run or lap is a separate question.

Norm I can see in theory less weight is better for any performance car and definitely agree with it(assuming weight reduction in the right places) and try to do it!

But given a 3600 lb solid sway bar car will it go slower than a 3592 lb car with the hollow bar, a 0.002% difference in weight? And we will be able to measure it in lap times on a 2.5 mile road course? Again dropping the discussion the bars are identical rates. I'd just bet you even most professional drivers would have enough lap variablity(tank level, tire stick,track temp etc etc) on a car without the bar change to not be able to measure that much weight change improvement with the bar change. Look at the NASCAR boys lap times when at road courses, or national autoX times- I'd bet the same car same course has more variation than what even the engineering formulas would predict in perfectly identical runs is all I'm saying.

How many of you guys here that do track time have lap times the same to the 0.01 second for all laps that day?

[wmhjr]

You keep missing the point.

It's not just the difference in weight of the two bars. It's that, PLUS the differences in other parts. A pound here, a half pound there.

You're also missing another very important point. Yes, there is clearly more variability in driver performance. So what? The perfect car with the perfect drive would in theory yield the best performance. Doesn't exist (Sorry Brian, et al...) Introducing driver variability in this discussion is a worthless activity. No value whatsoever. Just because the driver isn't good enough to always take advantage of it, doesn't mean it isn't an advantage.

By your logic, ANY change that isn't doesn't result in significant improvements should be disregarded. That would result in a pretty crappy car. I seriously doubt that replacing a well performing solid bar with a tubular lighter bar by itself will result in any measurable change.

Like I said - probably not worth pulling a good performing sway bar and replacing it on a mainly street car just for weight savings. But the really good cars are filled with well thought out details everywhere, and try to take advantage in every area. I was helping a friend at the track yesterday (drags) and that's mainly the difference between very consistent good cars, and those that were not as good. Attention to detail. Focus on the little things. The SUM of the parts and the design. You also need to recognize that not everyone is a consistent racer and that they may not have the ability to have shelves of parts. That also means that sometimes you need to find some really strong resources. There are a few here who are sponsors, and my experience thus far has been very positive. Marcus for example encouraged me to NOT replace sway bars until I had a chance to drive the car with the other suspension changes we implemented. It's a credit to some of our sponsors that they give what I consider good, experienced advice rather than just trying to sell every part they carry.

BTW, my car has a tubular Hellwig front bar. I needed a new bar. Since I needed one, getting a the Hellwig bar was a good choice.

[MrQuick]

I know a bunch of guys that spend thousands just to loose 15lbs. But good discussion.

[Skip Fix]

"I have a 79 Z-28 with Hotchkis springs/Bilsteins and Nitto 555's. I have a 1 1/8" factory sway bar on it now. I am looking at either the hollow Hotchkis sway bar 1 3/8" or the Addco solid sway bar
1 3/8". Losing the weight would be nice, but would there be much difference in the cornering capabilities between the two bars? Any advice would be great."

We ARE talking about the difference between a hollow vs solid. I get it's part of the whole package, total weight loss with other light weight components- I'm not that dense to figure that. But the question and most of the discussion from the start is swapping a bigger hollow bar going to perform better than a solid bar? The engineering theory that most is the outer portion so the hollow can be effective-part of the debate but we'll ignore that for this. And the advertising pushes that and the lighter weight WILL be better just from the sway bar and you go faster. Then just doing a sway bar swap and saving 8 lbs should be able to be verified on the track. Tell us-using a scienced out car(assuming his has all the other bells and whistles or using a pro car, pro driver, already a good solid front bar for it's set up) and swapping a hollow bar for a solid bar will it make a change in lap times or a seat of the pants feel?

Simple question-not debating a 100 lbs lighter will make a difference for all that light weight stuff also added on-just bar A vs bar B.