Printable Version of Topic
Click here to view this topic in its original format
914World.com _ 914World Garage _ Can we have a chat about rear sway bars please?
Posted by: Tdskip Mar 11 2018, 10:03 AM
So I scored a 19mm front bar, wondering now about rear bars. This is for a fast road, touring event, ‘74 with a 3.2 build.
I like cars that are tidy in their handling but would prefer not to leave the road backwards...
Also looking to confirm that I can always address the real sway bar later because it’s bolt on that does not require any welding work?
Take me to school here please!
Posted by: Steve Mar 11 2018, 10:25 AM
I run a rear for the street, but I disconnect it when I autocross.
Tight autocross turns it will cause one of the front wheels to lift.
There are sway bar reinforcement plates that are supposed to be welded in the rear trunk. I don’t know if these plates are required for all years. I did not install them on my 75.
Some people say don’t run one unless you have a limited slip trans. I ran mine way before I got a LSD.
Posted by: Montreal914 Mar 11 2018, 10:26 AM
Front and rear sway bars were factory installed in the front and rear on 73 2.0. 74 and on were an option. You may or may not have the brackets installed on your car depending if your car originally came equipped with them.
If the car didn't, you will need to weld in brackets in the front and back. A few options are available for the front if you do a search.
Once these are installed, then the sway bars are bolt on/off.
I have a 19mm SB in the front, stock in the back. Stock front suspension, 140lbs springs in the back. My car is has a 2056-4 and is lowed a little. Direzza tires 195/55-15 on 2.0 Fuchs 5.5".
I like it but I'm no expert, others will chime in. 
Posted by: Tdskip Mar 11 2018, 10:30 AM
Thank you for the fast responses and ideas/considerations.
What/where am I looking to see if the car has the factory rear mounts already?
Posted by: Tdskip Mar 11 2018, 10:31 AM
This?
Attached image(s)
Posted by: gereed75 Mar 11 2018, 10:37 AM
There are a couple of reinforcement plates that are welded into the trunk floor on the factory rear sway installation. There are a number of threads that show the details
Beyond that, it is generally felt that the rear bar is not necessary and maybe detrimental to a good handling fast street/track car.
My personal experience (six with 2.4S, 205 street tires, 19 mm front bar, 140# rear springs) is that on track the car is pretty neutral with dynamics more dependent on tire limits and throttle than front rear roll stiffness.
Don’t overthink it. Go with the conventional wisdom (good front bar, no rear, medium weight rear springs) and have fun. Oh yea, don’t lift - rear trailing arm suspension/trailing throttle oversteer dynamics still apply!!
Posted by: Steve Mar 11 2018, 10:38 AM
This?
Yes and reinforcement plates in the trunk
Posted by: SirAndy Mar 11 2018, 10:41 AM
I like them, a lot of people don't. I run a stock rear bar on my car.
Posted by: Tdskip Mar 11 2018, 10:46 AM
Thanks gentlemen. I have a reasonable amount of welding to do on this car anyway, and I'm wondering if I should put the mail it's in reinforcements in while the engine is out just to be on the safe side. What do you think?
Posted by: Steve Mar 11 2018, 10:56 AM
This?
Yes and reinforcement plates in the trunk
Not for sale, they are flat and easy to make your own.
Posted by: ClayPerrine Mar 11 2018, 12:20 PM
On both Betty's 4 and my conversion 6, we run both front and rear bars. Betty's is totally neutral through all corners. Mine has some understeer, but that is because I don't have big enough tires on the front.
I would suggest start with the factory sway bar setup, both front and rear. Then adjust from there.
Posted by: Edward Blume Mar 11 2018, 01:08 PM
I like them, a lot of people don't. I run a stock rear bar on my car.
I always ran a rear bar on my /4 AX car. Never had lift on the front. Rear bar boxes the front, front boxes the rear. I also had a weld in bar tying the longs.
With a 3.2 ???? who knows, you have other variables.
Posted by: Tdskip Mar 11 2018, 03:30 PM
This is a picture taken from underneath the car looking up, I'm assuming the brackets if they were installed by the factory would be visible here, right?
Posted by: Montreal914 Mar 11 2018, 03:54 PM
Actually here:
Google is your friend 
And this would be the right side reinforcement plate in the trunk:
Posted by: Larmo63 Mar 11 2018, 04:03 PM
You can look at my car next time you see it. I have factory mounts as my car is an early '73 appearance group 914S model. 
I welded the pickups on the consoles and firewall for adjustable struts too. I like having the rear sway bar, what's not to like?
Posted by: Tdskip Mar 11 2018, 05:13 PM
You can look at my car next time you see it. I have factory mounts as my car is an early '73 appearance group 914S model.
I welded the pickups on the consoles and firewall for adjustable struts too. I like having the rear sway bar, what's not to like?
Thanks for the offer, will do.
And to answer your other question - snap oversteer!
Posted by: Tdskip Mar 11 2018, 10:24 PM
I checked and I don’t have them...
Does the reinforcement at the top simply weld inplace to strengthen the metal on the top side of the mount or are longer mounting bolts used to tie the top and bottom pieces together?
Posted by: bbrock Mar 12 2018, 08:41 AM
This?
Yes and reinforcement plates in the trunk
Not for sale, they are flat and easy to make your own.
Any chance you could post the dimensions of this? I need to replace mine after repairing a rusted trunk pan but must have tossed the pattern I cut into the scrap pile by mistake.
Posted by: Tdskip Mar 12 2018, 09:00 AM
If these are correct it appears that the top reinforcement plates are simply welded in place to stiffen that metal? 
Posted by: bbrock Mar 12 2018, 09:02 AM
If these are correct it appears that the top reinforcement plates are simply welded in place to stiffen that metal?
Yep.
Posted by: dr914@autoatlanta.com Mar 12 2018, 09:04 AM
I would not use any rear sway bar with a 19mm front. The sixes are already tail happy and a rear bar would only accentuate that.
So I scored a 19mm front bar, wondering now about rear bars. This is for a fast road, touring event, ‘74 with a 3.2 build.
I like cars that are tidy in their handling but would prefer not to leave the road backwards...
Also looking to confirm that I can always address the real sway bar later because it’s bolt on that does not require any welding work?
Take me to school here please!
Posted by: Dave_Darling Mar 12 2018, 03:15 PM
It also depends on what else you've done to the suspension. Remember, the suspension is a system, and is usually best approached as a system.
For instance, stiffer rear springs can give you rear roll rate instead of a rear sway bar. Likewise, larger front torsion bars can give you front roll rate instead of a larger front sway bar.
Tire sizes, alignment, and even driving style also play into things.
--DD
Posted by: Tdskip Mar 12 2018, 03:25 PM
Thanks for the discussion and thoughts.
Looks like the safest bet right now is to install the brackets so they're there if I ever want to install a bar but leave a rear bar off for now and just drive her and see how she feels , yes?
Posted by: colingreene Mar 12 2018, 03:33 PM
i have a 20mm front bar 19mm torsion bars up front
140 pound rear springs and a stock sway bar. the rear sway bar makes the car more predictable for me on the street and easier to power over steer.
Posted by: jmitro Mar 12 2018, 04:54 PM
It also depends on what else you've done to the suspension. Remember, the suspension is a system, and is usually best approached as a system.
For instance, stiffer rear springs can give you rear roll rate instead of a rear sway bar. Likewise, larger front torsion bars can give you front roll rate instead of a larger front sway bar.
Tire sizes, alignment, and even driving style also play into things.
--DD
+1.
Posted by: gothspeed Mar 12 2018, 05:57 PM
I like them, a lot of people don't. I run a stock rear bar on my car.
You can look at my car next time you see it. I have factory mounts as my car is an early '73 appearance group 914S model.
I welded the pickups on the consoles and firewall for adjustable struts too. I like having the rear sway bar, what's not to like?
Posted by: infraredcalvin Mar 12 2018, 09:15 PM
It also depends on what else you've done to the suspension. Remember, the suspension is a system, and is usually best approached as a system.
For instance, stiffer rear springs can give you rear roll rate instead of a rear sway bar. Likewise, larger front torsion bars can give you front roll rate instead of a larger front sway bar.
Tire sizes, alignment, and even driving style also play into things.
--DD
Best advice thus far...
Posted by: rhodyguy Mar 13 2018, 10:51 AM
OEM F&R bars, stock torsion bars, Koni red ext adj F&R, 100# springs on adj perches. Elephant poly-bronze upfront. Dreamy on the road. Predictable.
Posted by: mbseto Mar 13 2018, 12:25 PM
Can you tell if you're lifting a wheel while driving, or do you need someone outside the car watching?
Posted by: stugray Mar 13 2018, 03:05 PM
I run no rear bar on my racecar but I have 225# springs in the rear
Posted by: jmitro Mar 13 2018, 05:22 PM
Can you tell if you're lifting a wheel while driving, or do you need someone outside the car watching?
I have super slo-mo video of my BMW M3 lifting a front wheel back when i was racing. I could not tell from inside the car
Powered by Invision Power Board (http://www.invisionboard.com)
© Invision Power Services (http://www.invisionpower.com)