Elephant QuickChange Blade Style Sway Bars

[aldente295]

Has anyone installed these? Comparisons with stock or other performance sways?

Swaybars are next on the suspension upgrade list....


Al

[wildcat077]

I went with a full Tarret package consisting of camber plates and front and rear adjustable swaybars and my car could not be happier.

The adjustability is great and so is the quality of Ira's products !

Cheers
Phil

[911pcars]

Originally Posted by aldente295

Has anyone installed these? Comparisons with stock or other performance sways?

Swaybars are next on the suspension upgrade list....

Al

Blade-type adjustable sway bars are pretty trick. Most often found on track cars. Do you need to quickly/conveniently fine-tune the anti-roll rate, on the fly or in the garage? If so, these might the answer. YMMV.

Sherwood

[Mahler9th]

Very, very few Porsche track cars I have seen during the past 30 years have used bladed sway bars. DIY cars, pro race cars, factory cars, cars on budgets, cars without budgets, a pretty broad range.

As some may recall, years ago Automotion (the original) offered a bladed set up as an alternative to Weltmeisters, factory bars and the scant few other commercial products available (if any). I am pretty sure these parts were designed and built by E.R.P. (no not Elephant company). The offering did not last long as Automotion was sold not too long after that. I don't think the parts sold well.

If I recall correctly, Craig Watkins designed and launched the SRP bars, and Ira (et al?), designed and launched the Tarrett bars. Both great products that have seemed to meet the market needs for the vast majority of Porsche racing applications where these products are available.

Now for the latest in water-cooled racing set ups... different story. But I don't think Elephant has any meaningful experience with high level amateur or pro racing water-cooled racing. If I were campaigning a later water-cooled car, I would try to access a consultant or consultants with pro experience.

[Flieger]

A blade style is harder for the novice to adjust correctly because the stiffness is very nonlinear with the orientation of the blade. With changing lever arm length like with Taretts you have a very linear relationship between how much you change the lever arm (by moving the bolt closer or further from the bar axis) to how much you change the stiffness. With a blade type the bar is supposed to deflect only minimally and the one blade controls the stiffness. The problem is that the blade is in bending and unless the blade is at 0 degrees or 90 degrees the moment of area of the beam (blade) takes a lot more number crunching to find, and it is the moment of area which controls how much roll stiffness you are adding. I will put it this way: I am a mechanical engineer and I would not want to find that moment of area (even though I could); I wouldn't even want to write a computer program to find it - too much work! When I upgrade my sway bars I will go with the classic adjustable lever type.

[Trog]

I installed them a while ago and am very happy with them.

My Elephant Racing Suspension Upgrade

I did have to lock-tight and wire the fixed-end hex-bolt as they were loosening up. Other than that, easy to install, easy to adjust, and so far they have been smooth and silent. My previous Tarrat down-link Heim joints had started clunking.

[Flieger]

All heim joints will wear out. It is just a matter of mileage/use.

[DG624]

Max, when changing suspension parts I lose my way. How much is enough and how do I test to find out?
How will more torsion bar stiffness affect handling? More rear bar reduces rear lean but promotes more rear sliding...
How will more rear sway bar stiffness affect handling? Similar rear stiffness but only on cornering not on bumps...

How much is the critical question and how can we determine the best compromise between street and track? Is there a general rule for sway bar stiffness as compared with torsion bar or spring stiffness? Should a car with stiff TBs not add much sway bar stiffness?

[Flieger]

The thing that changes the handling balance is not the absolute stiffness (assuming a reasonably smooth road) but rather the distribution of roll stiffness between the front and rear. More precisely, it is the lateral weight transfer that causes the track to loose cornering power. More lateral weight transfer at the front means understeer. More at the back means oversteer. Your total weight transfer will be essentially the same no matter if your car is stiff or if it is Cup Car stiff (body roll will cause a shift in cg to the outside of the turn that will increase the weight transfer if you make the car really soft). So it is all about how you proportion that between front and rear.

In a pure turning situation (no pitch, no bumps) sway bars essentially do the same thing as the torsion bars in that they both add elastic roll stiffness. Therefore, you don't need either or both on all cars, as the other thing to consider is the roll center height at each end, as this adds geometric roll resistance and reduces the roll couple that the elastic elements need to react. (In the more extreme cases, such as a swing axle on a formula vee, you might see no traditional rear springs at all; only a "Z bar" or "heave spring" that is the opposite of a sway bar and works only when both wheels move the same direction. The roll center height at the rear is plenty high enough for a car with such a low cg that there is no need for any elastic roll resistance.) There would then only be one anti-roll bar at most: an adjustable one at the front.

For a 911 you get the front to rear ride frequency ratio right and your pitch and heave stiffnesses where you want it, then you get the roll stiffness you want with anti roll bars (preferrably adjustable). I don't encounter too many bumps that hit both wheels at once, so to me there isn't any real reason that "big sways, soft torsion bars" should have a better ride than the opposite if you are assuming the same roll stiffnesses. On the contrary, the big sways will transfer weight faster at the instant of a bump on one wheel, meaning that handling, if not ride, will be worse with the big sway bars. I also don't like the pitch to be more pronounced than roll. As a result, I would ideally spec the rear springs a bit stiff and use only a front anti roll bar to tune handling. This gives more ground clearance out back and reduces weight a bit. It also helps get the rear ride frequency up (since lightened 911s typically end up even more rear heavy than stock) which provides a more level ride. With torsion bars, however, you can't always get as stiff as you'd like. Hence coil-overs.

I can't give you good rules of thumb for an amateur. For that I would tell you to talk to racers in your area or else suspension shops like Elephant or Rebel. I can tell you that stiff torsion bars means less sway bar, if you want to hold roll angle constant.

Pros calculate what the elastic weight transfer and geometric weight transfer is for each wheel based on the roll center heights, spring and sway bar stiffnesses, cg height, track widths, etc. And this ignores dampers which are responsible for a lot of the transient behavior on turn entry. The pros will then look at their tire data and determine what the optimal distribution of that weight transfer is to give the best balance. Most of this stuff is not what an amateur would have.

For 911 club racers I would say go as stiff as possible on the rear torsion bars, get something that matches in the front, and use an adjustable anti-sway bar at the front to tune the handling by making small changes throughout a session until you find what you like.

Remember, too that stiffer rear means less weight on the inside tire, which means more inside wheel spin and more need for a limited slip differential.

[911pcars]

Originally Posted by Mahler9th

Very, very few Porsche track cars I have seen during the past 30 years have used bladed sway bars. DIY cars, pro race cars, factory cars, cars on budgets, cars without budgets, a pretty broad range.

As some may recall, years ago Automotion (the original) offered a bladed set up as an alternative to Weltmeisters, factory bars and the scant few other commercial products available (if any). I am pretty sure these parts were designed and built by E.R.P. (no not Elephant company). The offering did not last long as Automotion was sold not too long after that. I don't think the parts sold well.

If I recall correctly, Craig Watkins designed and launched the SRP bars, and Ira (et al?), designed and launched the Tarrett bars. Both great products that have seemed to meet the market needs for the vast majority of Porsche racing applications where these products are available.

Now for the latest in water-cooled racing set ups... different story. But I don't think Elephant has any meaningful experience with high level amateur or pro racing water-cooled racing. If I were campaigning a later water-cooled car, I would try to access a consultant or consultants with pro experience.

I'll let Max respond to your questions, but there's plentiful information in reference books (Puhn, How To Make Your Car Handle and others) and specific setups for the gamut of Porsches in this and other Porsche forums.

One doesn't necessarily have to plot the mathematical torsional stiffness between full soft and full hard on a blade-type sway bar (as long as full hard is too hard). Between the two extremes, the control system usually has fixed detents for however many mid-settings they want for reference rather than an infinite hard-to-soft cable adjuster like a vintage bike derailleur.

During testing, perform a best-guess/past history/follow the crowd estimate of the front/rear roll rates, then adjust according to lap times and desired handling. Mid-sway bar settings are for fine-tuning. Unless your last name is Alonso, Hamilton, etc., many teams put the controls out of reach to make the driver's job less complicated. Testing and practice should arrive at the best setting, just like adjusting ride height, camber, toe, etc.

How many times do car enthusiasts adjust the sway bar settings on their street-based cars? Typically once - when installing. Most don't even know the difference between under and oversteer. Others might even consider this product bling or "nice-to-have" unless there's a purpose to have that capability. I've seen blade-type sway bars on a Honda Element. There you go.

As for ER, I don't think there are many layers between the person who answers the phone and the person who provides engineering and tech. support for the products they sell. Try that with other parts suppliers. If a team is at some threshold competition level, they'll most likely consult with "the Man" if at all possible. I doubt many F1 teams deal with Tire Rack instead of directly with Pirelli. And another reason my friends don't ask me.

Sherwood

[winders]

Originally Posted by Flieger

The thing that changes the handling balance is not the absolute stiffness (assuming a reasonably smooth road) but rather the distribution of roll stiffness between the front and rear. More precisely, it is the lateral weight transfer that causes the track to loose cornering power. More lateral weight transfer at the front means understeer. More at the back means oversteer. Your total weight transfer will be essentially the same no matter if your car is stiff or if it is Cup Car stiff (body roll will cause a shift in cg to the outside of the turn that will increase the weight transfer if you make the car really soft). So it is all about how you proportion that between front and rear.

Let use the proper term here: Roll Couple Distribution

You alter "roll couple distribution" to change the chassis balance oversteer/understeer characteristics.

"Weight transfer" is a really murky term and technically inaccurate. "Load transfer" is much better. The stiffer (in roll) end of the car handles more of the lateral load transfer when turning.

If you stiffen one end of the car, that end will handle more of the load (and the other end will handle less) and will generate less grip. So, if you have a car that is understeering, and you want to reduce or eliminate that, you need to soften the front roll resistance or stiffen the rear roll resistance.

Scott

[Flieger]

tomato, to-mah-toe. how much downforce you makin'?

[aldente295]

Thanks for all the feedback so far.

My assumption was that most people would replace both front and rear with adjustable, but Max you're saying that you really only need to do one end?

So, if I already have fatter torsion bars and sport shocks on both F and R with standard sways, then I could replace the front swaybar with an adjustable sway, and dial it in harder or softer to increase or decrease over/under steer...? (assuming the centre setting on the adjustable sways is roughly equal to 'standard')

I do about 6 track days a year, the rest of the time it's my (and the wife's) DD, so I want something quick and easy to change on race day without affecting driveability the rest of the time.


Al

[Flieger]

Having both adjustable just gives you a wider range of adjustment, probably more than you'd need. If you are going to have 2 sway bars and the extra cost isn't too much of an issue I would go for both adjustable, as the bushings and such on the aftermarket ones are more performance oriented, even if you might not adjust them both. I was just saying that you don't automatically need 2 sway bars or any sway bars at all. If you can get the torsion bars stiff enough then you just need a front adjustable bar to fine tune.

[Schmierung]

Max habt recht.

[mpetry]

I am going to be installing an ER blade type sway bar soon. My car's current (stock) sway bars are not holding me back in any way. What (up) sold me to Elephant's blade bar was the quick adjustability without removing the wheels - AND the blade bar has a unique attachment to the front A-arm that requires no welding or drilling.

I have the Elephant adjustable spring plates on the rear of my car, and they are really slick - far better than the "adjustable" spring plates offered by other 3rd party suppliers. Like all of ER's products, the blade bar looks like a very nice, well engineered part. I will report back after I've had a chance to play with it.

[Flieger]

I hadn't noticed the attachment to the A-arm. Interesting. I certainly wouldn't do it that way, but I guess if the loads are small it will work.

[911pcars]

Originally Posted by Flieger

I hadn't noticed the attachment to the A-arm. Interesting. I certainly wouldn't do it that way, but I guess if the loads are small it will work.

If anything, the ER bar allows faster/easier SB adjustments. Accessibility is one reason why bar adjustment isn't more often performed. If you tried it in a home garage, you know what I mean. The end to adjust must be elevated with the suspension loaded (e.g. on tire ramps) for complete access.

Sherwood

[Flieger]

I can't really comment on the ease of adjustment. Doesn't seem too hard to jack the car up and take a wheel off to slide the bolt or move it to a different hole or turn a blade either way.

I was just saying I wouldn't have put the load through the small diameter tube that is there to take braking force. I would have put it thorough the deep[er] section square tube that the ball joint goes on and which transmits the ride spring force from the torsion bar. I'd want to do some calcs to make sure there was enough friction to hold the shaft collar in place too (mainly from rotating). There are reasons Porsche put the clevis for the factory sway bars where they did.

[911pcars]

Originally Posted by Flieger

I can't really comment on the ease of adjustment. Doesn't seem too hard to jack the car up and take a wheel off to slide the bolt or move it to a different hole or turn a blade either way. .................

Yes. That's pretty easy. Jack the car up and shorten or lengthen the SB arms as desired. However, that's also assuming the corner heights on that end are exactly the same. If corner-balanced, each corner ride height might be slightly different. If you don't want a preloaded bar at rest (weight-jacked), then you'll want to adjust the SB arm angle for the most efficient geometry and one or both drop link lengths to achieve 0 preload. That's performed, of course, with the suspension on that end fully loaded at rest, not unloaded as it would be on jack stands.

:... or turning a blade either way." Yes. That was my point. Adjusting the sway bar by rotating the cable-controlled blade arm is much easier - from the cockpit if desired. The question is, do your driving conditions really necessitate such convenience?

Sherwood