How to ELIMINATE Understeer - 101
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Joined: Jun 2001
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From: Virginia Beach, Va.
How to ELIMINATE Understeer - 101
Well, what can I say...I thought I had seen it all, that was until...SNAP!!
I was at VIR, North Course, chasing or being chased. I was working on catching up to a nicely decked out 964 Cup car while CONSTANTLY letting Manny pass by, when it happened:
<img src="http://boards.rennlist.com/upload/snappedswaybar.jpg" alt=" - " />
Yup, that's part of my swaybar I'm holding!! <img border="0" title="" alt="[Eek!]" src="eek.gif" />
I was finishing up turn 2 when I heard and FEALT a POP...but nothing dramatic happened, although the steering felt a bit sloppy.
Of course, I dropped my pursuit and "tip-toed" around the track, my arm permanently out the window for a passing signal and went into the pits.
My girlfriend knew something was wrong as I NEVER pull in early (no jokes here). <img border="0" title="" alt="[Wink]" src="wink.gif" />
I was fairly confident something had happened to the swaybar...and I was right...it snapped right off, just before one of the bends.
What caused this??
...overagressive driving??
...improper installation??
...previous incident started fracture??
I vote for the last one, as a swaybar should NOT break under load and I did in fact install it correctly...how tough is that anyway? <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />
Needless to say, my understeer issue was solved for the rest of the weekend...wasn't too bad in the rain!
Well, all is good and kudos goes out to Performance Products/Weltmeister who offered to replace the 25.4mm HOLLOW "Cup" swaybar due to Weltmeister's 30month warranty...unbeknownst to me.
They would NOT however, exchange it for one of their 22mm units that I want to try, I do have a bit of understeer on sharp or off-camber turns. They can only replace with an EXACT unit.
SO, the offer is out there, anyone who wants a BRAND NEW 25.4mm HOLLOW (equivalent stiffness of an RS 24MM bar but 1/3 the weight) in trade for a decent 22MM setup...it's YOURS! <img border="0" alt="[bigbye]" title="" src="graemlins/xyxwave.gif" />
I was at VIR, North Course, chasing or being chased. I was working on catching up to a nicely decked out 964 Cup car while CONSTANTLY letting Manny pass by, when it happened:
<img src="http://boards.rennlist.com/upload/snappedswaybar.jpg" alt=" - " />
Yup, that's part of my swaybar I'm holding!! <img border="0" title="" alt="[Eek!]" src="eek.gif" />
I was finishing up turn 2 when I heard and FEALT a POP...but nothing dramatic happened, although the steering felt a bit sloppy.
Of course, I dropped my pursuit and "tip-toed" around the track, my arm permanently out the window for a passing signal and went into the pits.
My girlfriend knew something was wrong as I NEVER pull in early (no jokes here). <img border="0" title="" alt="[Wink]" src="wink.gif" />
I was fairly confident something had happened to the swaybar...and I was right...it snapped right off, just before one of the bends.
What caused this??
...overagressive driving??
...improper installation??
...previous incident started fracture??
I vote for the last one, as a swaybar should NOT break under load and I did in fact install it correctly...how tough is that anyway? <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />
Needless to say, my understeer issue was solved for the rest of the weekend...wasn't too bad in the rain!
Well, all is good and kudos goes out to Performance Products/Weltmeister who offered to replace the 25.4mm HOLLOW "Cup" swaybar due to Weltmeister's 30month warranty...unbeknownst to me.
They would NOT however, exchange it for one of their 22mm units that I want to try, I do have a bit of understeer on sharp or off-camber turns. They can only replace with an EXACT unit.
SO, the offer is out there, anyone who wants a BRAND NEW 25.4mm HOLLOW (equivalent stiffness of an RS 24MM bar but 1/3 the weight) in trade for a decent 22MM setup...it's YOURS! <img border="0" alt="[bigbye]" title="" src="graemlins/xyxwave.gif" />
Burning Brakes
Joined: Jun 2001
Posts: 1,003
Likes: 2
From: Texas
Jeff, I heard a pop coming from my suspension at the end of a PCA autocross this past weekend. I was already done with my last run and making a U turn in the parking lot when I heard it. I was releasing the clutch at that time, so I thought perhaps it was the clutch popping back. Based on your incident, I definitely need to go over my swar bars as I have a feeling one of them may have popped loose.
Thread Starter
Race Car
Joined: Jun 2001
Posts: 3,706
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From: Virginia Beach, Va.
Yup, just a note to ALL of you guys running autocrosses, track events and racing...CHECK YOUR SUSPENSION FITTINGS EACH AND EVERY TIME!! 
This was just a plain old BREAK, everything was adjusted and installed correctly, no nuts/bolts loose...just a freak incident.
John, I believe I read the PM that you sent in reply...neat stuff, plan on trying it out sometime...just didn't have the time when I posted the "UGLY Mug" pic above. <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />
...plus, someone had mentioned they wanted to see a face with a name someday. Now that you're all in horror, I'll go back to just posting pics of boring car parts, etc.
This was just a plain old BREAK, everything was adjusted and installed correctly, no nuts/bolts loose...just a freak incident.
John, I believe I read the PM that you sent in reply...neat stuff, plan on trying it out sometime...just didn't have the time when I posted the "UGLY Mug" pic above. <img border="0" alt="[hiha]" title="" src="graemlins/roflmao.gif" />
...plus, someone had mentioned they wanted to see a face with a name someday. Now that you're all in horror, I'll go back to just posting pics of boring car parts, etc.
Burning Brakes
Joined: Jun 2001
Posts: 1,003
Likes: 2
From: Texas
Whew! The sway bars are fine, so I have no idea what the noise was. Probably the clutch pedal.
Jeff: I copied your suspension setup (965 H&R's with Bilstein HD's), and threw on a strut bar and front camber plates. It's been a KILLER setup for autocrossing. The understeer is noticeably reduced, and I can do things with the car that I couldn't before.
Jeff: I copied your suspension setup (965 H&R's with Bilstein HD's), and threw on a strut bar and front camber plates. It's been a KILLER setup for autocrossing. The understeer is noticeably reduced, and I can do things with the car that I couldn't before.
Addict
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Joined: Nov 2001
Posts: 1,097
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From: Maryland
Drew,
Disconnect your front bar for autocrossing and you'll be more amazed---virtually no understeer
I usually to lazy to disconnect and run it with the front bar and end up cussing at myself mid way through the run because I'm trying to transfer weight with the throttle to reduce the understeer, BUT , the times I have disconnected it, I was a happy boy!
Disconnect your front bar for autocrossing and you'll be more amazed---virtually no understeer
I usually to lazy to disconnect and run it with the front bar and end up cussing at myself mid way through the run because I'm trying to transfer weight with the throttle to reduce the understeer, BUT , the times I have disconnected it, I was a happy boy!
Driver Carries No Cash
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Joined: Nov 2001
Posts: 1,441
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From: Tampa, Florida
</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by Manny Alban:
<strong>Drew,
Disconnect your front bar for autocrossing and you'll be more amazed---virtually no understeer
</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I've heard this suggestion before, but I find myself scratching my head thinking WTF?
Could one you gurus please explain the mechanics/physics of this little trick for the terminally slow. I have visions of horrible body roll with the front bar disconnected.
Do you disconnect the sway bar from the drop links on one or both ends?
Thanks!
<strong>Drew,
Disconnect your front bar for autocrossing and you'll be more amazed---virtually no understeer
</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">I've heard this suggestion before, but I find myself scratching my head thinking WTF?
Could one you gurus please explain the mechanics/physics of this little trick for the terminally slow. I have visions of horrible body roll with the front bar disconnected.
Do you disconnect the sway bar from the drop links on one or both ends?
Thanks!
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Specialist
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Joined: Jun 2001
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From: springfield, MO USA
Jeff, I vaugely recall that you had some trials & tribulations in installing this bar. Some deal with using hose clamps or something? Am I not recalling correctly? Mabey your modifications / installation was NOT correct? Honestly, I believe your going agricultural probably may have had something to do with it.
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Race Car
Joined: Jun 2001
Posts: 3,706
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From: Virginia Beach, Va.
Terry, you only need to disconnect one drop link and that leaves the swaybar inoperable. Tie the droplink back with tie wraps, etc.
As for WHY this works...the 911 tends to understeer anyway, and several of us have upgraded to stiffer front swaybars...if you eliminate the STIFF function of said swaybar, the weight in your front end will transfer rapidly under steering load, and you still have the rear swaybar, so now you will have an OVERSTEER situation which can be reduced by either dialing a lower setting (if you have an adjustable rear) or removing a link from it!
Trust me, I had an interesting time dealing with OVERSTEER the rest of the weekend, but being that the remainder of the weekend was in the rain, it made it kinda fun. <img border="0" alt="[jumper]" title="" src="graemlins/jumper.gif" />
Horst, I tend to believe so as well...it's quite obvious that's what encouraged the fracture. <img border="0" alt="[grrrrrrr]" title="" src="graemlins/cussing.gif" />
As for WHY this works...the 911 tends to understeer anyway, and several of us have upgraded to stiffer front swaybars...if you eliminate the STIFF function of said swaybar, the weight in your front end will transfer rapidly under steering load, and you still have the rear swaybar, so now you will have an OVERSTEER situation which can be reduced by either dialing a lower setting (if you have an adjustable rear) or removing a link from it!
Trust me, I had an interesting time dealing with OVERSTEER the rest of the weekend, but being that the remainder of the weekend was in the rain, it made it kinda fun. <img border="0" alt="[jumper]" title="" src="graemlins/jumper.gif" />
Horst, I tend to believe so as well...it's quite obvious that's what encouraged the fracture. <img border="0" alt="[grrrrrrr]" title="" src="graemlins/cussing.gif" />
Advanced
Joined: Jan 2003
Posts: 79
Likes: 0
From: Colorado
Jeff,
I have wondered about the swaybar sizes that I have seen discussed. You want to move from a 24 mm bar (=24.5 hollow) to a 22 mm bar. That should reduce understeer somewhat. Are you trying to reduce understeer?
Strabo
I have wondered about the swaybar sizes that I have seen discussed. You want to move from a 24 mm bar (=24.5 hollow) to a 22 mm bar. That should reduce understeer somewhat. Are you trying to reduce understeer?
Strabo
Thread Starter
Race Car
Joined: Jun 2001
Posts: 3,706
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From: Virginia Beach, Va.
Yup, trying to reduce understeer at the track...otherwise it's a VERY fun setup.
For the person who is a "spirited" driver at the track and on the road, this swaybar works out great...but if you want to put in some killer lap times, the Hoosiers tend to understeer you a bit on the sharper turns...hence the desire to try out a 22mm setup.
For the person who is a "spirited" driver at the track and on the road, this swaybar works out great...but if you want to put in some killer lap times, the Hoosiers tend to understeer you a bit on the sharper turns...hence the desire to try out a 22mm setup.
