Spreader bar questions
05-31-2017, 09:57 AM
#23
Drifting
I am not going to speak for everyone, but I will speak for myself. I installed a big block in my 76, along with big block springs, and a big block swaybar. The front felt good, but it felt as if it was dipping in the corners which ever way I was leaning. Well a few months later someone here on the forum was selling a spreader bar and I bought it. I installed it as suggested and I do not have the dipping anymore, and honestly a few less squeaks. I do know physically when the car is sitting on the ground, I cannot turn the bar by hand, but if I just take a little weight off, I can turn the bar by hand.
Oh, and then I woke up from my nap
Oh, and then I woke up from my nap
05-31-2017, 11:20 AM
#25
Racer
my experience with the spreader bar was different then the majority here. i have install 1 11/4" up front and 7/8 rear stabilizer bar,upper lower A frame bushing,Bilstein shocks,and got rid of the terrible struct set-up then i installed VBP spreader bar almost centered on A-frame because i have no fan,shroud,a/c compressor so i welded brackets so bar is only 1/4" from pulleys to get as close to center as possible. i don`t have to much experience drag racing on track but all the time on street. i have 700R4 and 2600 stall with 525 dyno. hp 408" built by the best,so i power brake but that does not work to well the car starts rolling forward around 2200.the problem was prior to the spreader bar installation the car would lift front left wheel and veer off to the right uncontrollable . now car stays straight from 0 to 140mph then starts to lift in front.the correct installation of the spreader bar works wonders for safety.thank you "skull" for your advise ,other then machine work i do everything myself so i take advise.
Last edited by Captain bob; 05-31-2017 at 11:34 AM.
05-31-2017, 12:44 PM
#26
Le Mans Master
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No I am suggesting that what you perceive as making a difference is simply a reduction in rattle / noises / firmness in the frame, and not a handling improvement.
It is simply based on the bar doesn't effect any major changes to the alignment stability on the street and therefor effect the handling.
Never said it didn't do anything at all, but claims of improved handling while cornering / response on turn in etc, etc, on the street it is nothing more than the extra confidence you may have and driving a corner faster than you would normally. This alone gives you a extra rush that makes you feel good.
Now driving on a road course with super sticky tires at the limit of the tires, you will have a better chance at holding the alignment in the corners with a bar vs without one.
eg at my local track I get a max of ~ 1.15 g's in some corners. Not a chance I would attempt this on any street road. So for me its hard to get the WOW factor on the street.
The best benefit of the bar is the reduce body flexing / rattles / noises this doesn't give you confidence when your car rattles. With the bar installed and the noises reduced it just feels better to the ears and mind.
The blind test would show what our mind imagines and what is real. I would bet most wouldn't tell the difference in other than noise alone. And on a smooth road would never tell the difference with or without one.
It is still worth installing because the benefit vs cost is great. I have never heard anyone be disappointed installing one. If it makes you feel better about your car, its worth it.
It is simply based on the bar doesn't effect any major changes to the alignment stability on the street and therefor effect the handling.
Never said it didn't do anything at all, but claims of improved handling while cornering / response on turn in etc, etc, on the street it is nothing more than the extra confidence you may have and driving a corner faster than you would normally. This alone gives you a extra rush that makes you feel good.
Now driving on a road course with super sticky tires at the limit of the tires, you will have a better chance at holding the alignment in the corners with a bar vs without one.
eg at my local track I get a max of ~ 1.15 g's in some corners. Not a chance I would attempt this on any street road. So for me its hard to get the WOW factor on the street.
The best benefit of the bar is the reduce body flexing / rattles / noises this doesn't give you confidence when your car rattles. With the bar installed and the noises reduced it just feels better to the ears and mind.
The blind test would show what our mind imagines and what is real. I would bet most wouldn't tell the difference in other than noise alone. And on a smooth road would never tell the difference with or without one.
It is still worth installing because the benefit vs cost is great. I have never heard anyone be disappointed installing one. If it makes you feel better about your car, its worth it.
05-31-2017, 01:02 PM
#27
Drifting
Member Since: Oct 2001
Location: Halifax, Nova Scotia, Canada
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I've been driving the same Corvette for 47 years. I've drag raced strip and street, as well as "other" aggressive driving.
I believe I have a good "feel" for my car.
I recently installed a spreader bar and within the first mile, I could definitely feel the improvement. Basically an overall improved firmness in the feel. One of the most noticeable changes I've made, and no, it's not just in my head.
I believe I have a good "feel" for my car.
I recently installed a spreader bar and within the first mile, I could definitely feel the improvement. Basically an overall improved firmness in the feel. One of the most noticeable changes I've made, and no, it's not just in my head.
05-31-2017, 01:21 PM
#28
Le Mans Master
I am not going to speak for everyone, but I will speak for myself. I installed a big block in my 76, along with big block springs, and a big block swaybar. The front felt good, but it felt as if it was dipping in the corners which ever way I was leaning. Well a few months later someone here on the forum was selling a spreader bar and I bought it. I installed it as suggested and I do not have the dipping anymore, and honestly a few less squeaks. I do know physically when the car is sitting on the ground, I cannot turn the bar by hand, but if I just take a little weight off, I can turn the bar by hand.
Oh, and then I woke up from my nap
Oh, and then I woke up from my nap
This is how I discovered just how much the spreader bar stiffens the front suspension. I set my bar with the weight on the tires since that is where my caster/camber/toe were set. I could then comfortably rotate the bar about the Heim joints while the car was sitting level. Later I jacked my front end up to do something, placing jack stands under the frame (adjacent to the lower control arm mounts). As I was working on the front end, I happened to place my hand on the spreader bar and realized that I could now only twist it with great effort. It was clear that with the weight off of the suspension, the frame was now "twisted" enough that the bar was under great tension.
It seems clear to me that as the front suspension goes from compression to extension, particularly so in tight turns or rapid stops and accelerations such as in autocrossing, the front alignment geometry has to be changing. I think I'll keep it!
Good luck... GUSTO
Last edited by GUSTO14; 05-31-2017 at 01:23 PM. Reason: syntax
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Captain bob (07-10-2017)
05-31-2017, 01:21 PM
#29
Racer
to the orignal poster (Kacyc3)
I have a 74 coupe, sbc, 355 with serpentine brackets and accessories from a 92 carprice, dual electric fans, and VBP spreader bar.
My springs are 550#, cut 1 quarter of a coil to make them fit into the pockets correctly. All the bushings are poly, the steering box is borgeson, Bilstien sport shocks. I still have the old 15x8 torque thrust II's with 245/60r15s. The other mod i did was to mill the upper control arm cross shafts 1/4". This was based on a few old posts by Norvalwilhelm. the reason I did this was to get higher than stock castor (Max 2.5 degrees.) I ended up with 3.1 degrees of castor which works out nicely with the Borgeson box. No squirrlely-whirlly on the highway.
I have a 74 coupe, sbc, 355 with serpentine brackets and accessories from a 92 carprice, dual electric fans, and VBP spreader bar.
My springs are 550#, cut 1 quarter of a coil to make them fit into the pockets correctly. All the bushings are poly, the steering box is borgeson, Bilstien sport shocks. I still have the old 15x8 torque thrust II's with 245/60r15s. The other mod i did was to mill the upper control arm cross shafts 1/4". This was based on a few old posts by Norvalwilhelm. the reason I did this was to get higher than stock castor (Max 2.5 degrees.) I ended up with 3.1 degrees of castor which works out nicely with the Borgeson box. No squirrlely-whirlly on the highway.
05-31-2017, 03:04 PM
#30
Drifting
Thread Starter
to the orignal poster (Kacyc3)
I have a 74 coupe, sbc, 355 with serpentine brackets and accessories from a 92 carprice, dual electric fans, and VBP spreader bar.
My springs are 550#, cut 1 quarter of a coil to make them fit into the pockets correctly. All the bushings are poly, the steering box is borgeson, Bilstien sport shocks. I still have the old 15x8 torque thrust II's with 245/60r15s. The other mod i did was to mill the upper control arm cross shafts 1/4". This was based on a few old posts by Norvalwilhelm. the reason I did this was to get higher than stock castor (Max 2.5 degrees.) I ended up with 3.1 degrees of castor which works out nicely with the Borgeson box. No squirrlely-whirlly on the highway.
I have a 74 coupe, sbc, 355 with serpentine brackets and accessories from a 92 carprice, dual electric fans, and VBP spreader bar.
My springs are 550#, cut 1 quarter of a coil to make them fit into the pockets correctly. All the bushings are poly, the steering box is borgeson, Bilstien sport shocks. I still have the old 15x8 torque thrust II's with 245/60r15s. The other mod i did was to mill the upper control arm cross shafts 1/4". This was based on a few old posts by Norvalwilhelm. the reason I did this was to get higher than stock castor (Max 2.5 degrees.) I ended up with 3.1 degrees of castor which works out nicely with the Borgeson box. No squirrlely-whirlly on the highway.
05-31-2017, 08:42 PM
#31
I was using a setup I wasnt famailar with so not sure I set it up correctly but it showed -3.5* LF and -1.4 RF Camber, 3.0 LF and 4.4 RF Camber, toe .05 LF and .04 RF. The car is stable in flat straight road, crowns and change in pavement lines make it interesting and "darty" or "twitchy".
not sure I read the 3.0 & 4.4 as caster ? you listed camber twice.
But the important part is left vs right. I would try to get similar caster / camber on both sides.
But if that is the best camber they can do you are in a tuff spot. The car will handle as you say "darty" or "twitchy"
For daily driver camber should be near 0 for best tire life, with the other adjustment done correctly.
There are many posted specs for alignment. There was a post I saw once where someone collected them. Here is the one I see most often
http://tech.corvettecentral.com/2011...ignment-specs/
05-31-2017, 08:45 PM
#32
I would start with 0 camber on both sides and measure what you can get for caster.
If you can get 2.75 positive also on both sides this is a very good starting point.
05-31-2017, 08:53 PM
#33
Great this that I would like to measure with and without one to know the "real effect" of the single bar. Forget about the firm feeling and noises / rattles we all agree we notice this.Anyone know if there is a way to measure this in real time ?
05-31-2017, 09:09 PM
#34
Le Mans Master
First, with the car settled on the ground, remove the bar. Measure from one upper control arm, to the opposite upper control arm. Then lift the car until the tires leave the ground and place jack stands under the frame adjacent to the lower control arm mounting points. Now take the above measurement again.
I suspect that there will be a difference of about a half inch. Of course this can also vary somewhat depending upon the structural integrity of the frame.
Good luck... GUSTO
05-31-2017, 09:33 PM
#35
I would think that all you need to do is take a couple of measurements.
First, with the car settled on the ground, remove the bar. Measure from one upper control arm, to the opposite upper control arm. Then lift the car until the tires leave the ground and place jack stands under the frame adjacent to the lower control arm mounting points. Now take the above measurement again.
I suspect that there will be a difference of about a half inch. Of course this can also vary somewhat depending upon the structural integrity of the frame.
Good luck... GUSTO
First, with the car settled on the ground, remove the bar. Measure from one upper control arm, to the opposite upper control arm. Then lift the car until the tires leave the ground and place jack stands under the frame adjacent to the lower control arm mounting points. Now take the above measurement again.
I suspect that there will be a difference of about a half inch. Of course this can also vary somewhat depending upon the structural integrity of the frame.
Good luck... GUSTO
But this measurement would be interesting to see with different cars. I am sure the results will be surprising.
05-31-2017, 10:03 PM
#36
I would think that all you need to do is take a couple of measurements.
First, with the car settled on the ground, remove the bar. Measure from one upper control arm, to the opposite upper control arm. Then lift the car until the tires leave the ground and place jack stands under the frame adjacent to the lower control arm mounting points. Now take the above measurement again.
I suspect that there will be a difference of about a half inch. Of course this can also vary somewhat depending upon the structural integrity of the frame.
Good luck... GUSTO
First, with the car settled on the ground, remove the bar. Measure from one upper control arm, to the opposite upper control arm. Then lift the car until the tires leave the ground and place jack stands under the frame adjacent to the lower control arm mounting points. Now take the above measurement again.
I suspect that there will be a difference of about a half inch. Of course this can also vary somewhat depending upon the structural integrity of the frame.
Good luck... GUSTO
I measure the distance between the bar brackets.
On the ground still connected it measured 20"
Removed the bar on the ground disconnected 20" No surprise here.
Lifted both front wheels off the ground. bar disconnected. Jacked as you suggested.
20 1/16" so not much change for me.
I then only lifted 1 side of the car to check compression. It was impossible for me to measure a difference with a tape measure.
I would think with real driving forces the effect might be higher.
But it seems there is little flex in my 78 Frame using this test.
Last edited by cagotzmann; 05-31-2017 at 10:05 PM.
06-21-2017, 11:11 PM
#37
Drifting
Thread Starter
Yes the camber was -3.4 LF and -1.4RF, 3.0 LF and 4.4 RF Caster. I have since removed the shims on the LF that sent camber so high, it's still darty and the toe is off as the tires squeal a little and make powder on the fenders.
06-21-2017, 11:34 PM
#38
Sorry been hectic prepping for and completing the head swap on the car.
Yes the camber was -3.4 LF and -1.4RF, 3.0 LF and 4.4 RF Caster. I have since removed the shims on the LF that sent camber so high, it's still darty and the toe is off as the tires squeal a little and make powder on the fenders.
Yes the camber was -3.4 LF and -1.4RF, 3.0 LF and 4.4 RF Caster. I have since removed the shims on the LF that sent camber so high, it's still darty and the toe is off as the tires squeal a little and make powder on the fenders.
Squeal and powder shows its way out. Since the shop alignment didn't get things working it may be worth a DIY Attempt.
06-22-2017, 07:10 PM
#39
Drifting
Thread Starter
07-10-2017, 11:05 AM
#40
Drifting
Thread Starter
I used a level for the length and I know its truer than anything else in my garage and a clinometer ap on my phone. I didnt expect it to be 100% accurate but close enough. The DS shows -2.9* camber with all shims removed. PS showed just over -1*, i gave the car toe out and its less darty but that will change with camber anyway. Guess Im going to have to put it on a frame table.