Hotchkis Sway Bar
#1
Jim51
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Hotchkis Sway Bar
Is this new?
just noticed mention on suspension forum. From the Hotchkis website:
Features:
Front Sway Bar:
Lightweight, durable and adjustable 1-5/16” (33mm) hollow
110% stiffer than the stock sway bar with a rate of 970 lbs/in
150% stiffer than the stock sway bar with a rate of 1150 lbs/in
195% stiffer than the stock sway bar with a rate of 1370 lbs/in
Seems like just the ticket for BS.
just noticed mention on suspension forum. From the Hotchkis website:
Features:
Front Sway Bar:
Lightweight, durable and adjustable 1-5/16” (33mm) hollow
110% stiffer than the stock sway bar with a rate of 970 lbs/in
150% stiffer than the stock sway bar with a rate of 1150 lbs/in
195% stiffer than the stock sway bar with a rate of 1370 lbs/in
Seems like just the ticket for BS.
#2
No respecter of malarkey
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deleted my previous comment
someone told me they rigged a custom test rig using this bar and the numbers were close
strictly from a theoretical calculation they don't seem to make sense, but that's all I've ever had to base any numbers on. I've never seen any hard data collection done except on the splined-type speedway sway bars
someone told me they rigged a custom test rig using this bar and the numbers were close
strictly from a theoretical calculation they don't seem to make sense, but that's all I've ever had to base any numbers on. I've never seen any hard data collection done except on the splined-type speedway sway bars
#3
Jim51
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I went back and ran the numbers myself, and can match the rates quoted using some reasonable assumptions on tube thickness. However, I only just this moment finally figured out the % increase relative to stock. I was thinking the low setting was 110% of the stock stiffness, but it is actually 210% of the stock stiffness ("110% stiffer"). Now the math finally makes sense. Now I believe this bar is probably too stiff for BS.
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I'll look forward to the article.
I don't have my measurements in front of me, but when I drill the extra hole in the OE FSB, it should move the endlink points forward by roughly a 1/2"-3/4". Any idea how much % stiffer the bar becomes (over the stock setting)? Is this question perhaps answered as well in the SportsCar article?
I don't have my measurements in front of me, but when I drill the extra hole in the OE FSB, it should move the endlink points forward by roughly a 1/2"-3/4". Any idea how much % stiffer the bar becomes (over the stock setting)? Is this question perhaps answered as well in the SportsCar article?
#7
05-08 SCCA BS Natl Champ
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I'll look forward to the article.
I don't have my measurements in front of me, but when I drill the extra hole in the OE FSB, it should move the endlink points forward by roughly a 1/2"-3/4". Any idea how much % stiffer the bar becomes (over the stock setting)? Is this question perhaps answered as well in the SportsCar article?
I don't have my measurements in front of me, but when I drill the extra hole in the OE FSB, it should move the endlink points forward by roughly a 1/2"-3/4". Any idea how much % stiffer the bar becomes (over the stock setting)? Is this question perhaps answered as well in the SportsCar article?
#8
No respecter of malarkey
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I've used the same spacing on my bars from several years back, and again it doesn't theoretically calculate out to an 85% adjustment range
OE hole is 7.375" from the main bar centerline, that means the forward most hole would be at 6.875" and the rearmost hole at 8.0"
Just look at the ratio of a 1.125" adjustment range relative to the length of the arm, it's nowhere near 85%
Based on theoretical calculations, an 85% adjustment range relative to a nominal endlink hole position 7.375" would be outside the angular reach of the OE endlink. I have plenty of tested rate data on splined speedway bars and it matches the calculations well.
http://www.intercomp-racing.com/Prod...TESTER_778.cfm
if you read my earlier post, I'm trying to understand why the two aren't lining up (no pun intended)
Last edited by TeamRX8; 01-31-2008 at 02:40 PM.
#9
05-08 SCCA BS Natl Champ
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I think you misunderstood what I was trying to say
I've used the same spacing on my bars from several years back, and again it doesn't theoretically calculate out to an 85% adjustment range
OE hole is 7.375" from the main bar centerline, that means the forward most hole would be at 6.875" and the rearmost hole at 8.0"
Just look at the ratio of a 1.125" adjustment range relative to the length of the arm, it's nowhere near 85%
Based on theoretical calculations, an 85% adjustment range relative to a nominal endlink hole position 7.375" would be outside the angular reach of the OE endlink. I have plenty of tested rate data on splined speedway bars and it matches the calculations well.
http://www.intercomp-racing.com/Prod...TESTER_778.cfm
if you read my earlier post, I'm trying to understand why the two aren't lining up (no pun intended)
I've used the same spacing on my bars from several years back, and again it doesn't theoretically calculate out to an 85% adjustment range
OE hole is 7.375" from the main bar centerline, that means the forward most hole would be at 6.875" and the rearmost hole at 8.0"
Just look at the ratio of a 1.125" adjustment range relative to the length of the arm, it's nowhere near 85%
Based on theoretical calculations, an 85% adjustment range relative to a nominal endlink hole position 7.375" would be outside the angular reach of the OE endlink. I have plenty of tested rate data on splined speedway bars and it matches the calculations well.
http://www.intercomp-racing.com/Prod...TESTER_778.cfm
if you read my earlier post, I'm trying to understand why the two aren't lining up (no pun intended)
#11
Jim51
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The soft setting is 110% stiifer than (or 2.1 times) the stock rate, and the stiffest is 195% stiffer than (or 2.95 times) the stock rate. Nominal is 150% stiffer than (or 2.5 times) the stock rate.
Therefore the adjustments amount to +18%/-16% or about what you would expect.
#13
Jim51
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I'll look forward to the article.
I don't have my measurements in front of me, but when I drill the extra hole in the OE FSB, it should move the endlink points forward by roughly a 1/2"-3/4". Any idea how much % stiffer the bar becomes (over the stock setting)? Is this question perhaps answered as well in the SportsCar article?
I don't have my measurements in front of me, but when I drill the extra hole in the OE FSB, it should move the endlink points forward by roughly a 1/2"-3/4". Any idea how much % stiffer the bar becomes (over the stock setting)? Is this question perhaps answered as well in the SportsCar article?
For 1/2", this would be (7.375/(7.375-.5))^2=115%
For 3/4" it would be (7.375/(7.375-.75))^2=124%
The stiffness of the arm itself has a VERY slight effect on this, not worth worrying about.
#14
Jim51
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FWIW, I estimated the following in terms of relative stiiffness based on available diameters and wall thicknesses:
Stock = 1 (baseline)
Stock redrilled = 1.2
Mazdaspeed =1.2
Whiteline =1.5 (center hole) ~1.2-1.7 estimated range
Racing Beat = 2.1
Progress = 2.6 (center hole) ~2.1-3.1 estimated range
Hotckis =2.5 (center hole), 2.1-2.95 range
Stock = 1 (baseline)
Stock redrilled = 1.2
Mazdaspeed =1.2
Whiteline =1.5 (center hole) ~1.2-1.7 estimated range
Racing Beat = 2.1
Progress = 2.6 (center hole) ~2.1-3.1 estimated range
Hotckis =2.5 (center hole), 2.1-2.95 range
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FWIW, I estimated the following in terms of relative stiiffness based on available diameters and wall thicknesses:
Stock = 1 (baseline)
Stock redrilled = 1.2
Mazdaspeed =1.2
Whiteline =1.5 (center hole) ~1.2-1.7 estimated range
Racing Beat = 2.1
Progress = 2.6 (center hole) ~2.1-3.1 estimated range
Hotckis =2.5 (center hole), 2.1-2.95 range
Stock = 1 (baseline)
Stock redrilled = 1.2
Mazdaspeed =1.2
Whiteline =1.5 (center hole) ~1.2-1.7 estimated range
Racing Beat = 2.1
Progress = 2.6 (center hole) ~2.1-3.1 estimated range
Hotckis =2.5 (center hole), 2.1-2.95 range
![Ylsuper](https://www.rx8club.com/images/smilies/ylsuper.gif)
#18
The Whiteline 27mm solid bar has three adjustments, i.e. two holes per side.
Center to center, we got 1/2" forward on the stock bar, IIRC.
#19
Jim51
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I don't know the exact hole locations for any of the above, but I assumed center was same as stock, and +/- 10% (~3/4") for the adjustments.
What is the spacing on the Whiteline holes? If they straddle the stock hole location then that rate would be about right for the "middle" adjustment (one forward, one back), but the range may be smaller.
What is the spacing on the Whiteline holes? If they straddle the stock hole location then that rate would be about right for the "middle" adjustment (one forward, one back), but the range may be smaller.
#21
Jim51
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Anyone have any info on the Tanabe swaybars? I found some references in a search, but no details or discusion of BS use.
30.5mm, hollow and chrome-moly is all I can find. I can't find any data to support their claim that CrMo is substantially stiffer in torsion (as opposed to stronger/tougher) than other steels, but the diameter seems like it would be in the right range for BS (though not adjustable).
30.5mm, hollow and chrome-moly is all I can find. I can't find any data to support their claim that CrMo is substantially stiffer in torsion (as opposed to stronger/tougher) than other steels, but the diameter seems like it would be in the right range for BS (though not adjustable).
#23
Jim51
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![Smilie](https://www.rx8club.com/images/smilies/smile.gif)
Seriously, I don't plan to make any changes until I get a bit of a feel for the car, but I would like to know what the options are. My thought is that the car will probably be faster with a little more roll stiffness, but I know that discussion has been beat to death.
Looking forward to the first local event in <2 weeks, then into the fray at the Dixie Tour.
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Does anyone have and test and tune data on slalom times with stiffer FSB settings?
I need to get my Maxqdata thing working so I can look at some of these variables better (actually never really have, so anything will be better) this year.
I need to get my Maxqdata thing working so I can look at some of these variables better (actually never really have, so anything will be better) this year.
#25
Jim51
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Found my own answer. Cr-Mo is about 10% stiffer than carbon steel, so I'm guessing the Tanabe bar is about 1.7X the stock bar., similar to the Whiteline on stiffest setting, a little lighter, but no adjustability.