……
Corvair DiagramCorvair Photo
Corvair Center
home forum corvairs calendar links Corvair Podcast
California Corvairs
Clarks Corvair
Clarks Corvair
“CORSA"



Chevy Corvair License Plate
Chevy Corvair Chrome Wheel
Corvair Center Forum :  Corvair Center Phorum - presented by CORSA The fastest message board... ever.
Corvair Center 
Current Page: 2 of 4
Re: Improving EM Handling
Posted by: DreamRyder1963 ()
Date: April 22, 2013 07:08PM

That pic definitly helps. I assume that on a corvair, the bar would be mounted lower. Possibly just under and forward of the diff.

Joseph Bates
1963 Corvair 700 sedan
1964 Corvair Monza Rat
2012 Mazda3 i Sport sedan
Corryton, TN
[www.dracoautodesigns.com]

Options: ReplyQuote
Re: Improving EM Handling
Posted by: mwr ()
Date: April 22, 2013 07:18PM

The Z bar doesn't do the same thing as a sway bar, the main thing it does is prevent the rear suspension from jacking. It would be way down the list of things to do for getting a street car rear suspension in shape. In fact, I'd look at pretty much every other thing you were thinking about first.

Options: ReplyQuote
Re: Improving EM Handling
Posted by: MattNall ()
Date: April 22, 2013 07:25PM

Looks dangerous to me! I built mine with one body pivot and one end pivot on the A-arm...

Worked as an anti -sway..... but was too low for my car...

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: Improving EM Handling
Posted by: Pacerace ()
Date: April 22, 2013 07:30PM

Seems to me like it would act the exact opposite of an anti-sway bar. I could be wrong but it seems it would increase the roll in the rear end? But I would imagine the roll would be better than jacking, and can be reduced with a front anti-roll bar.

________________________________________________________

Chandler
Powder Springs, GA.



1965 Corvair Monza 110/4sp Coupe

Options: ReplyQuote
Re: Improving EM Handling
Posted by: mwr ()
Date: April 22, 2013 07:50PM

Yes, the opposite of a sway bar. It shouldn't have any effect on roll since it is basically allowing each side of the suspension do what it wants to do already, compress on loaded side and do the opposite on the other. Probably the best way to think about it is that it doesn't allow the unweighted side to stay stuck in the down position (jack), it helps pull it back up into neutral position. The only time it has any effect on stiffness is when both side are under compression, which would be putting a twisting force on the bar.

Options: ReplyQuote
Re: Improving EM Handling
Posted by: MattNall ()
Date: April 22, 2013 08:07PM

Reminds me of this EM Ax'r... guy said it worked well!

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Attachments:
Options: ReplyQuote
Re: Improving EM Handling
Posted by: ensys ()
Date: April 22, 2013 08:13PM

First; mia culpa on the '64 setup. I had forgotten that it took the same approach as Porsche's camber compensator which is, it is important to note, aptly named. The only function of this approach is, as noted previously, is to reduce the rear roll stiffness (which is the opposite of the function of a sway or anti-roll bar)

As implemented by Porsche (and I assume, by GM), the compensator was accompanied by a markedly softer spring rate (to reduce roll stiffness) and only acted in one direction to carry the static load, thus maintaining ride height and hence camber, that the softer springs could not. This was effective to a certain degree, but did not counteract the tendency to jack when conditions pressed hard enough.

The Zbar's sole function is to counteract jacking, not to carry weight, so that when the inside wheel drops, its weight forces the outside wheel up. Mr.Pacerace has grasped the principle almost correctly with the exception that it does not increase nor decrease roll stiffness.

The Zbar is very effective and has been in use by racers since the '70s. The only issue for street cars is that correct mounting is difficult (the chassis anchor points must be quite rigid, and in most situations, it is best mounted below the gearbox, confounding maintenance and occasional removal), particularly if maintaining a basically stock configuration is important.

The foto provided shows it as correctly mounted. Mr.Nall, the mounting you describe is not just wrong, its downright scary, no offence intended.

Mr.Skirmants' product is not a Zbar, it is a virtual Zbar because it is a transverse spring that mimics the effect of an actual Zbar. He did not invent it, but he did bring an effective version to market.

Additional note: Because the idea is to reduce roll stiffness, the rear shocks should be as soft as possible.

Keep 'em flying...

S.J.Szabo

From America's
Automobile Heartland



Edited 1 time(s). Last edit at 04/22/2013 08:18PM by ensys.

Options: ReplyQuote
Re: Improving EM Handling
Posted by: MattNall ()
Date: April 22, 2013 08:46PM

ensys Wrote:
-------------------------------------------------------
> Mr.Nall, the mounting you describe is not just
> wrong, its downright scary, no offence intended.
=============================================================

You never drove the car... don't condemn it... It worked great , but was too low with my race wheels... on the street worked great! I had a Fiberglass bodied street buggy that had neutral handling....not easy to do!

And the car with a conventional U-bar ran up front with the Big Pigs at Flagstaff in 2001.. took 2nd in Specialty Class with Harlan Coburn and we were only beat by Warren LeVeque in "LeVair".. with a tired 145 ci / pg..

Luckily Seth and Mark [solo2r], were in a slower cars... ggg

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Attachments:
Options: ReplyQuote
Re: Improving EM Handling
Posted by: spydergear ()
Date: April 22, 2013 11:53PM

If you think of how the the Skirmantsbow works, it works exactly the same as a Z-bar with several advantages: Mounting, adjustability, ease of removal. The Z-bar on a Corvair would be difficult to mount and would probably require chassis reinforcements and welding. Louie Lira's highly modified Z-bar equipped car used fabricated suspension arms and was a dedicated race car.

If you think about it, the '64 setup could be converted to Z-bar by reversing the leaf so that it is bowed the opposite direction, then fabricating a center bracket, and leaf end shackles. There are problems, of course: The '64 differential housing mount is not strong enough (only two small bolts). Earlier housings would require some sort of fabricated bracket attached to the top of the diff (?). The affect on the motor mounts would have to be considered. The leaf may have the wrong spring rate.

Or, you could start from scratch: Use a 1965 or later differential housing attaching the bracket to the lower strut mounts. Have a multi-leaf spring made. Fabricate the center bracket and end shackles. Drill control arms or adapt '64 arms. Use the springs from a '62 - '63 Spyder.

Anyone care to do the engineering on this idea?

BTW, the '64 setup is not perfect on the street either. It has a tendency to pitch severely in the rear. Soft shocks just aggravate this.

Attachments:
Options: ReplyQuote
Re: Improving EM Handling
Posted by: mwr ()
Date: April 23, 2013 01:06AM

I see no point going to these extremes given that the '64 rear suspension already exists. Though seemingly few people have, there are plenty of opportunities to tweak it with different coil springs or different transverse spring. Steve Goodman reports using adjustable threaded end links to change transverse spring preload.

Also I am not sure what you mean by the spring pad on the '64 diff not being strong enough for what you are suggesting. A proper camber compensator will not load the center mount, and should be free to rock/pivot in the middle (look at the pic), and the original EMPI mount is cantilevered out far enough that if any major load was applied to it it would twist right off.



Edited 1 time(s). Last edit at 04/23/2013 01:07AM by mwr.

Options: ReplyQuote
Re: Improving EM Handling
Posted by: ensys ()
Date: April 23, 2013 01:49PM

Mr.Nall:

I'm afraid you misunderstand. My comments were not a critique; rather, they were in the spirit of fellowship that is this site, a warning, proffered in the same spirit that I'm sure you would warn a fellow who said that mounting his wheels backwards is a great idea for increasing the track of his 'vair ("and boy does it handle!").

I'm glad that your use of the past tense indicates you no longer use the setup you describe, for surely it would not behave symmetrically in use, a condition that very likely would, when you would least wish, result in no small surprise, at the very least.

Should you be so moved in the future to reconsider deploying this device, I urge you to first do some more research or, at the very least, discuss it with someone you trust and who has more than a passing acquaintance with the principles of the Zbar.

Best regards,

Keep 'em flying...

S.J.Szabo

From America's
Automobile Heartland

Options: ReplyQuote
Re: Improving EM Handling
Posted by: DreamRyder1963 ()
Date: April 23, 2013 07:04PM

I did some research while at work tonight, it was a slow night. I noticed that EM corvairs and a '63 Corvette call for the same shocks for the front. By that line of thought, I would think that proformance shocks/coilovers for the front of a corvette should be compatiable with EMs.

Joseph Bates
1963 Corvair 700 sedan
1964 Corvair Monza Rat
2012 Mazda3 i Sport sedan
Corryton, TN
[www.dracoautodesigns.com]

Options: ReplyQuote
Re: Improving EM Handling
Posted by: MattNall ()
Date: April 23, 2013 07:11PM

Vettes have a front engine... we only have 900 lb on the front..

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: Improving EM Handling
Posted by: DreamRyder1963 ()
Date: April 23, 2013 07:19PM

They would still be an upgrade due to their built-in ride height and internal valve adjustablity. The stiffer ones will be good for the rear of our cars.

Joseph Bates
1963 Corvair 700 sedan
1964 Corvair Monza Rat
2012 Mazda3 i Sport sedan
Corryton, TN
[www.dracoautodesigns.com]

Options: ReplyQuote
Re: Improving EM Handling
Posted by: MattNall ()
Date: April 23, 2013 07:44PM

ensys Wrote:
-------------------------------------------------------

> I'm afraid you misunderstand. My comments were not
> a critique; rather, they were in the spirit of
> fellowship that is this site, a warning, proffered
> in the same spirit that I'm sure you would warn a
> fellow who said that mounting his wheels backwards
> is a great idea for increasing the track of his
> 'vair ("and boy does it handle!").
===========================================================


I understand... we have a difference of opinion / experience... you have a picture... I don't!! ggg simple!


And actually reversing stock wheels on early Beetles [swingaxle] was a well proven mod... Early Formula V's did it as well [scca!] But their wheels mounted differently...non- hub-centric. just sayin!

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: Improving EM Handling
Posted by: Naderater ()
Date: April 24, 2013 12:10AM

Joseph, I set up my '63 coupe to replicate the description in a Road and Track test of a '64 Fitch Sprint. Fitch improved handling "by increasing roll resistance at the rear and decreasing it at the front so a higher percentage of weight transfer takes place at the front, a cheracteristic of understeer. This is accomplished in the Sprint by leaving the factory springs and shocks in place at the front of the car but removing the anti-sway bar to reduce the roll resistance. At the rear, the suspension is decambered and the roll resistance is increased by using heavier coil springs and specially made adjustable shock absorbers." My car came with a '64 dif and transverse spring and original (heavier) '63 coils. It looked like an old Beetle with all that rear spring. I cut a coil front and rear and used longer transverse spring bolts to restore the ride height to about 1 to 1.5° negative camber. There was no front anti-sway bar to remove. I used KYB KG5780 rear shocks (Chevy Epress 1500 van) as these seemed to have good damping, nearly original compressed (9.05") and extended (12.99") lengths for controlling wheel tuck, and also an internal extension stop to prevent damage to the shock when limiting tuck. I had to remove the cover with a Dremel and reuse the old rubber and washers. It seems like this would transfer body roll weight to the outside rear, incresing traction. Anyway, I like the result. A word of warning, a Corvair is heavier on the left than the right. So cut the left springs a bit long and check the ride height and camber frequently.

Barry

Options: ReplyQuote
Re: Improving EM Handling
Posted by: spydergear ()
Date: April 24, 2013 01:07AM

I see no point going to these extremes given that the '64 rear suspension already exists. Though seemingly few people have, there are plenty of opportunities to tweak it with different coil springs or different transverse spring. Steve Goodman reports using adjustable threaded end links to change transverse spring preload.

Yes, you could use stiffer springs front and rear. The leaf would no longer be carrying the same percentage of weight so its contribution would be less. Warren LeVeque, on the Doug Roe car, IIRC, used 800 lb springs rear, 600 lb front, no leaf. It still oversteered. Bob Coffin recommended using the leaf with stiffer cut '63 springs as you may be suggesting.

I am saying that there are limitations to the '64 design. I think the Skirmant's Bow may be worth a try. Like the Z-bar, it is more of an active anti-jacking device. If you are going to the trouble of making new transverse leafs for the stock setup, it is not much more work to make the bow (functioning as a Z-bar). Whatever is done, I think it needs to start with engineering (doing the math) and understanding the forces involved otherwise there will be a lot of trial and error.

Also I am not sure what you mean by the spring pad on the '64 diff not being strong enough for what you are suggesting. A proper camber compensator will not load the center mount, and should be free to rock/pivot in the middle (look at the pic), and the original EMPI mount is cantilevered out far enough that if any major load was applied to it it would twist right off.

The spring pad is just that: To locate the leaf and its rubber bushing mount. It is not designed to cope with a force in the opposite direction as the Skirmants Bow would exert. I have a diff case that was cracked through one of the mount pads and into the threads just from using the stock setup. So no, I don't think the stock setup would be strong enough to be the center pivot for the Bow.

Options: ReplyQuote
Re: Improving EM Handling
Posted by: caroseiii ()
Date: April 24, 2013 07:30PM

Joseph, I am using the 63-82 front Corvette Bilsteins on the rear of my 64 leaf spring suspension. The extended length is longer than stock and its gas pressurized, too. I don't recommend it without a leaf spring to limit swing arm travel. It has a generous tuck under. The best thing about the shocks is that the bolt holes are not slots! You can bolt on the shocks with no risk of them slipping out of the 5/16th bolts (which is very disconcerting).

You ought to search for NOS Delco shocks because there is a true design difference after 1962 in that these are harder to open than to close. This means that compression is easy but extension is slower to limit tucking.

I have 65 front suspension installed with a 64 bar and HD 64 springs. The new Clarks' 65-69 shocks for the front are gas pressurized also which is unfortunate because there is almost no movement. Very stiff. I bought cheap NORS oil shocks to evaluate the difference down the road.

Crawford



Edited 2 time(s). Last edit at 04/24/2013 07:34PM by caroseiii.

Options: ReplyQuote
Re: Improving EM Handling
Posted by: MattNall ()
Date: April 24, 2013 07:43PM

Crawford.. you'll like the oil only shocks up front..


And your too long rear shocks..with Holes...can use 1" tube spacers to cure the excessive tuck...

MODERATOR
Sea Mountain, between Charleston Harbor and Coos Bay! SW Oregon Coast
Click HERE for My Website...Click HERE for My TechPages!
...............110-PG.................................................Webered-Turbo

Options: ReplyQuote
Re: Improving EM Handling
Posted by: DreamRyder1963 ()
Date: April 24, 2013 08:38PM

Do you just put the space inbetween the lower shock mount and the lower control arm to negate the extra length?

Options: ReplyQuote
Current Page: 2 of 4


Sorry, only registered users may post in this forum.
This forum powered by Phorum.