Addco VS QA1 Sway Bar
Thread Starter
Instructor
Joined: Aug 2017
Posts: 216
Likes: 10
From: MD
Addco VS QA1 Sway Bar
I couldn't find a thread compares between say bars. A few months ago just changed a complete set of Borgeson Power Steering Conversion, I did see some improvement but I am looking for more, I am planning to add a front Sway bar and a rear one if it's necessary the plan is to add a better quality ride. my questions is.
1. which is better QA1 part number QA1 52820- or Addco part number 760.
2. Do I need to change the rear sway bar dose it add any improvements?.
My car set
for the front
QA1 shocks
Borgeson Power Steering Conversion.
just rebuilt the control arms
for the rear
Bilstein HD shocks.
lowered the rear leaf by 1 or 2 leaves + 2 new 8" bolts and bushings.
It's a weekend car I will not track it.
1. which is better QA1 part number QA1 52820- or Addco part number 760.
2. Do I need to change the rear sway bar dose it add any improvements?.
My car set
for the front
QA1 shocks
Borgeson Power Steering Conversion.
just rebuilt the control arms
for the rear
Bilstein HD shocks.
lowered the rear leaf by 1 or 2 leaves + 2 new 8" bolts and bushings.
It's a weekend car I will not track it.
Race Director
Joined: Mar 2017
Posts: 11,890
Likes: 4,472
From: Virginia
What year is your car, and do you really not have a front sway bar at all?
The Addco bar is basically a stock replacement from an 80-82 C3 (1 1/8" solid steel, which is what is stock in my 80).
The QA-1 bar is lighter, but you'll have to do the math to see if it is stiffer (1 1/4" OD, 3/16" wall thickness, hollow).
The stiff front bar in the 80-82, combined with the soft rear end (especially in 81-82 with the low-rate composite spring that was chosen) adds to understeer. So you may want to balance whatever you choose with a stiffer rear spring and/or rear sway bar. Did you remove leaves from your existing spring? Are you sure it isn't an FE7 gymkhana spring?
The Addco bar is basically a stock replacement from an 80-82 C3 (1 1/8" solid steel, which is what is stock in my 80).
The QA-1 bar is lighter, but you'll have to do the math to see if it is stiffer (1 1/4" OD, 3/16" wall thickness, hollow).
The stiff front bar in the 80-82, combined with the soft rear end (especially in 81-82 with the low-rate composite spring that was chosen) adds to understeer. So you may want to balance whatever you choose with a stiffer rear spring and/or rear sway bar. Did you remove leaves from your existing spring? Are you sure it isn't an FE7 gymkhana spring?
Race Director
Joined: Mar 2017
Posts: 11,890
Likes: 4,472
From: Virginia
The stock 1977 bar is solid, 7/8" diameter.
https://www.gmheritagecenter.com/doc...t-Corvette.pdf
Using this handy sway bar calculator:
http://www.gtsparkplugs.com/Sway-Bar-Calculator.html
I didn't measure my swaybar, so I'm guessing the width at 45", arm length at 8".
Edit: I did measure my swaybar. Width 33", arm length 5". The dimensions of all should be the same, so the relative torsional stiffness numbers should be relative.
EDIT: Updated with new measurements for the correct bar dimensions.
Stock 7/8" Bar: 775 lb/in
Stock 1" Bar: 1321 lb/in
Addco 1 1/8" Bar: 2116 lb/in (should be the same as the stock 80-82 1 1/8" bar)
QA-1 1 1/4" Bar: 2451 lb/in (Hollow, 1.25 - 0.375 = 7/8" ID, so your stock bar would fit exactly inside)
Solid 1 1/4" Bar: 3226 lb/in (Theoretical, I don't know of anyone who makes this)
These numbers are all relative, not absolute, so normalizing for your stock bar (divide all numbers by the 775 from the 7/8" bar). These numbers did NOT change, but I added a few.
7/8" Bar: 1.00
1" Bar: 1.70
Addco: 2.73
QA-1: 3.16
1.25" Solid: 4.16
So the QA-1 is slightly stiffer than the Addco bar (or the stock bar in my 80, for example), but is much lighter. Both aftermarket bars are about three time stiffer than what is on your car now.
I hope that helps!
https://www.gmheritagecenter.com/doc...t-Corvette.pdf
Using this handy sway bar calculator:
http://www.gtsparkplugs.com/Sway-Bar-Calculator.html
Edit: I did measure my swaybar. Width 33", arm length 5". The dimensions of all should be the same, so the relative torsional stiffness numbers should be relative.
EDIT: Updated with new measurements for the correct bar dimensions.
Stock 7/8" Bar: 775 lb/in
Stock 1" Bar: 1321 lb/in
Addco 1 1/8" Bar: 2116 lb/in (should be the same as the stock 80-82 1 1/8" bar)
QA-1 1 1/4" Bar: 2451 lb/in (Hollow, 1.25 - 0.375 = 7/8" ID, so your stock bar would fit exactly inside)
Solid 1 1/4" Bar: 3226 lb/in (Theoretical, I don't know of anyone who makes this)
These numbers are all relative, not absolute, so normalizing for your stock bar (divide all numbers by the 775 from the 7/8" bar). These numbers did NOT change, but I added a few.
7/8" Bar: 1.00
1" Bar: 1.70
Addco: 2.73
QA-1: 3.16
1.25" Solid: 4.16
So the QA-1 is slightly stiffer than the Addco bar (or the stock bar in my 80, for example), but is much lighter. Both aftermarket bars are about three time stiffer than what is on your car now.
I hope that helps!
Last edited by Bikespace; Oct 3, 2021 at 01:56 PM. Reason: Measured Bar.
QA1 will be my choice I am hopping to see some improvement in driving.
