M030 Anti-Roll Bars?
10-05-2003, 09:28 PM
#1
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M030 Anti-Roll Bars?
Evening all.
Just back from an enjoyable afternoon of running my 993, and it's clear that my suspension's in need of "love" (read: money). I'm pretty far along with the decision to go for the Bilstein HDs and the M030 springs, but I'm still a little unsure about how to handle the whole anti-roll bar question. Before putting my question to the board, I'll note that my car is used 95% for street and 5% for track (I satisfy that Jones with the SCCA).
I've read that my stock sways are (F/R) 20mm/17mm, and that the ROW M030 sways are 22mm/20mm. Thus, the increase in front roll stiffnes is 10% and at the rear it's 17.65%. On this basis (and I know I'm oversimplifying here), I'd expect the car to become somewhat more "oversteery" with the ROW M030 sways.
This should be a good thing, since the car does "push" in many circumstances. OTOH, an understeering car can be easier to drive and safer in many unexpected emergencies. The best example of this, and one I encounter from time to time on the crowded highways here in Chicago, is the curving off-ramp with stopped traffic. My concern is that, with more roll stiffness at the rear, the car will be harder to stop in a straight line, particularly in the wet.
Can I get a read from you M030 sway-bar-switchers (!) as to how much "looser" your street-driven 993s became when you switched bars? As well, can you say a little about the change in the car's transient performance after the switch?
BTW, I know the whole suspension question has been flogged pretty hard here, but I'd sure appreciate the group's expertise before making the plunge.
Regards to all.
Just back from an enjoyable afternoon of running my 993, and it's clear that my suspension's in need of "love" (read: money). I'm pretty far along with the decision to go for the Bilstein HDs and the M030 springs, but I'm still a little unsure about how to handle the whole anti-roll bar question. Before putting my question to the board, I'll note that my car is used 95% for street and 5% for track (I satisfy that Jones with the SCCA).
I've read that my stock sways are (F/R) 20mm/17mm, and that the ROW M030 sways are 22mm/20mm. Thus, the increase in front roll stiffnes is 10% and at the rear it's 17.65%. On this basis (and I know I'm oversimplifying here), I'd expect the car to become somewhat more "oversteery" with the ROW M030 sways.
This should be a good thing, since the car does "push" in many circumstances. OTOH, an understeering car can be easier to drive and safer in many unexpected emergencies. The best example of this, and one I encounter from time to time on the crowded highways here in Chicago, is the curving off-ramp with stopped traffic. My concern is that, with more roll stiffness at the rear, the car will be harder to stop in a straight line, particularly in the wet.
Can I get a read from you M030 sway-bar-switchers (!) as to how much "looser" your street-driven 993s became when you switched bars? As well, can you say a little about the change in the car's transient performance after the switch?
BTW, I know the whole suspension question has been flogged pretty hard here, but I'd sure appreciate the group's expertise before making the plunge.
Regards to all.
10-05-2003, 11:25 PM
#2
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The stiffness of the bars is proportional to the 4th power of the diameter. The difference is much more than you think. Divide the new dia by the old dia and raise to the 4th power.
The answer for the change from 20mm to 22mm is 46% stiffer.
The answer for the change from 20mm to 22mm is 46% stiffer.
10-05-2003, 11:26 PM
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Actually combined with the H&R coilover my cabrio is really a joy to drive fast. No concerns really, understeer is almost gone, the car feels very balanced. I really liked the upgrade which included the M030 sways.
Go for it!
Go for it!
10-06-2003, 02:42 AM
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Hi David,
No "looser" at all. In fact, I'd describe it as "closer to neutral" since I can still push the front or wag the back depending on how I drive it (no I don't do this on the street
). Buy them.
In the rain, no difference, but then again, 911s definitely require attention when driving in the rain anyway, even with the 20/17 bars. Hope this helps.
Edward
No "looser" at all. In fact, I'd describe it as "closer to neutral" since I can still push the front or wag the back depending on how I drive it (no I don't do this on the street
). Buy them. In the rain, no difference, but then again, 911s definitely require attention when driving in the rain anyway, even with the 20/17 bars. Hope this helps.
Edward