Rear sway bar, worth it?
11-23-2006, 03:16 PM
#21
Team Owner
Originally Posted by Jim_Harrison
If you were to drive your car in a constant circle, slowly increasing the speed, (Skid Pad) and the rear starts to slide out that is oversteer or the car is loose. If the front slides 1st then that is understeer or tight. A balanced car will have both ends slide at the same time. I drive best if my car has a very slight amount of understeer, then use the throttle to power oversteer the car. Some drivers like a car set up on the loose side, I find this works well with a C-5 Z06 but a C-3 due to poor rear design is becomes unpredictable and very unforgiving.
I am wondering about this stockish 9/16 rear bar I just installed in the rear.....I haven't done the front upgrade yet....to about an inch, instead of that thin thing on there now...
11-23-2006, 03:27 PM
#22
Melting Slicks
Member Since: Dec 2000
Location: Wichita, KS
Posts: 2,041
Likes: 0
Received 0 Likes
on
0 Posts
I will second the statement that C3's are unforgiving when they oversteer ... but crossed up and boiling the tires is sooo much fun!
Jim Harrison runs a C3 in the local autocross events. Having witnessed his powers at pushing a C3 rapidly through an autocross course I'm willing to pay close attention to any advice he is giving on handling.
Jim Harrison runs a C3 in the local autocross events. Having witnessed his powers at pushing a C3 rapidly through an autocross course I'm willing to pay close attention to any advice he is giving on handling.
11-23-2006, 03:30 PM
#23
Racer
Member Since: Aug 2006
Location: Wellington, New Zealand
Posts: 328
Likes: 0
Received 3 Likes
on
3 Posts
I have to agree with most of these posts, with a stiff rear end (big bar) you will go from 'good fun' to a 'spinning top' in a split second, these cars swap ends very quickly and too bigger rear bar will make this even worse.
11-23-2006, 04:34 PM
#24
Le Mans Master
Originally Posted by Jim_Harrison
If you were to drive your car in a constant circle, slowly increasing the speed, (Skid Pad) and the rear starts to slide out that is oversteer or the car is loose. If the front slides 1st then that is understeer or tight. A balanced car will have both ends slide at the same time. I drive best if my car has a very slight amount of understeer, then use the throttle to power oversteer the car. Some drivers like a car set up on the loose side, I find this works well with a C-5 Z06 but a C-3 due to poor rear design is becomes unpredictable and very unforgiving.
11-23-2006, 07:31 PM
#28
Tech Contributor
Member Since: Jun 2004
Location: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Posts: 18,346
Received 767 Likes
on
549 Posts
Originally Posted by Gordonm
I was at VB this winter and asked about this same problem since I went to 18 inch and wide rubber. The yset me up with a 420# rear spring and no rear bar. They told me this should work just as well as the 330# with a rear bar. It seems to be just as stable. No track time with it but on some aggresive driving it seems as good as before.
11-24-2006, 08:12 AM
#29
Racer
Member Since: Jan 2006
Location: Orange massachusettes
Posts: 395
Likes: 0
Received 0 Likes
on
0 Posts
I dont/havn't raced my car on road course or auto x (although I would like to try auto x ) The car is just a street car, that seemed to have WAY to much body roll going into corners. I stated my intentions to VB&P tech ( NOT sales clerk) at least THREE times and questioned use of such large sway bars w/ much heavier than stock spring rate. He assured me this package was MATCHED/BALANCED for street use. I like there products and trusted the tech, after all they must sell hundreds if not thousands of these different kits. Was I told wrong?? I havn't got car back together yet, and wont be able to tell how it handles untill spring time.(No pun intended) Surely, someone else on this forum runs a small block coupe w/ a similiar set up.
Last edited by 72 LT1; 11-24-2006 at 07:39 PM.
11-24-2006, 08:42 AM
#30
Team Owner
My '68 drag car was originaly a big block car and came with the rear sway bar. I removed it a while ago.. If anybody wants it, it can be picked up at my house for free....
11-24-2006, 05:38 PM
#31
Melting Slicks
I changed my spring to a 315 pound composit for a better ride and found it leaned too much in turns. I had a sway bar sitting around and with it, the lean is much less but still rides nice. A pushed it to see if any strange handling showed up and it seems ok. On the down side, the rear will squat under hard acceleration and its harder to brake the tires loose. I did have some fun with a ricer that followed me up a long hiway ramp. I just kept building speed on the turn untill he lost it and almost hit the guard rail.
11-25-2006, 02:26 AM
#34
CFOT Attention Whore
Originally Posted by turtlevette
NO its not worth it.
at least that's my initial opinion. like others have said, it's a tuning thing. i bought one years ago for my '81 when i autocrossed alot. i found that it made the rear very tail happy, so i just disconnected it. especially if you upgrade to a lower profile tire with less sidewall flex. because of the inherent design shortcomings of the c3 chassis, i'd suggest you get the front as tight as you can live with (depending on your style) and leave the rear until your happy with the front. once you get the front sorted out, then move to the rear. the car carries so little dynamic "weight" in the rear, that a driver would be better with soft rear for comfort and tight front for handling.
11-25-2006, 06:20 PM
#36
Racer
Member Since: May 2006
Location: Fort Myers, Fl / St. Paul, Mn
Posts: 264
Likes: 0
Received 0 Likes
on
0 Posts
Great thread and for me, well timed. My 72 SB coupe has some noticeable over-steer when taking a corner too fast. I've been contemplating removing the rear bar but have concerns about having a 1-1/8" front bar. Too big with no rear bar? Removing the rear seems like the thing to do for a street and freeway only driver. Don't want to be weaving in and out of traffic on the freeway and have the rear trying to take the lead.
I'm also going to replace the KYB rear shocks with something stiffer - it rides great except the rear seems to bob up and down compared to the front. VB&P mono on both ends.
I'm also going to replace the KYB rear shocks with something stiffer - it rides great except the rear seems to bob up and down compared to the front. VB&P mono on both ends.
11-26-2006, 10:31 PM
#37
CFOT Attention Whore
72 LT1, i don't know. what do you not like about the way your car handles? from what you described, and from my personal experience, i expect your car oversteers a bit. as such, and this is just a guess, your rear bar may be a tad too large.
see, the problem this thread doesn't address but has been brought up time and time again on this forum, is the spagetti-like stiffness of the c3 frame. in your instance, you use the frame as a spring. unlike in later model cars with much stiffer frames, our cars transmit so much dynamic force through the frame, we compensate by adding stiffer springs, swaybars and shocks.
i can tell you, literally, from personal experience that despite what i've done to try to tune the suspension on my '81, the handling still falls short of the c5. on top of that, the compromise in driver comfort hardly makes it worth it.
if you really want to drive these cars fast, you have to figure out a way to stiffen the frame.
see, the problem this thread doesn't address but has been brought up time and time again on this forum, is the spagetti-like stiffness of the c3 frame. in your instance, you use the frame as a spring. unlike in later model cars with much stiffer frames, our cars transmit so much dynamic force through the frame, we compensate by adding stiffer springs, swaybars and shocks.
i can tell you, literally, from personal experience that despite what i've done to try to tune the suspension on my '81, the handling still falls short of the c5. on top of that, the compromise in driver comfort hardly makes it worth it.
if you really want to drive these cars fast, you have to figure out a way to stiffen the frame.
11-26-2006, 11:37 PM
#38
Race Director
Originally Posted by GrandSportC3
My '68 drag car was originaly a big block car and came with the rear sway bar. I removed it a while ago.. If anybody wants it, it can be picked up at my house for free....
.....redvetracr
11-27-2006, 11:27 AM
#39
Le Mans Master
Originally Posted by big_G
If you upgrade to a rear bar, you should also up the front bar size. My preferences are 1-1/8 inch front, 5/8 inch for the rear. 
11-27-2006, 11:44 AM
#40
Originally Posted by turtlevette
On the highway in an emergency situation the car is going to swap ends when you swerve to avoid an object. No doubt about it. Leading to a crash. There is a reason the factory builds understeer into almost all passenger vehicles. It's much much safer.
