Steering, Suspension, & Brakes

tips, technology, tools and techniques related to non-driveline mechanical components

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roverman
Art Gertz
Winchester, CA.
(3149 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

2 bar with diagonal bar, coilover rear supension
Posted by: roverman
Date: January 08, 2014 04:05PM

I bought a car with this, and it's dumb ! Longitudal bars are front pivot only and diagonal bar binds on rear end housing. My thought is to use diagonal bar as a panhard. I could go watts, but that's more work. Car is approx 3,400 lbs, with approx. 700-800hp, up front. Suggestions ? Thanks, roverman.


Moderator
Curtis Jacobson
Portland Oregon
(4495 posts)

Registered:
10/12/2007 02:16AM

Main British Car:
71 MGBGT, Buick 215

authors avatar
Re: 2 bar with diagonal bar, coilover rear supension
Posted by: Moderator
Date: January 08, 2014 05:32PM

hmmm...

photo?


DiDueColpi
Fred Key
West coast - Canada
(1308 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: 2 bar with diagonal bar, coilover rear supension
Posted by: DiDueColpi
Date: January 08, 2014 07:02PM

So what you have Art, is a giant anti sway bar?


roverman
Art Gertz
Winchester, CA.
(3149 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: 2 bar with diagonal bar, coilover rear supension
Posted by: roverman
Date: January 08, 2014 07:26PM

Fred, Unwillingly-yes. Putting diagonal into bending moment, not my first pick, for anti-rol/lol. Set-up looks similar to most race car/4 bar w. diagonal systems, w/o. upper bars. Advantage of a "watts" vs. Panhard or "pickle fork" ? Cheers, roverman.


DiDueColpi
Fred Key
West coast - Canada
(1308 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: 2 bar with diagonal bar, coilover rear supension
Posted by: DiDueColpi
Date: January 08, 2014 07:54PM

What are the actual plans for the car?
Ie, street, road race, 1/4 mile etc.
And how much fabrication do you want to deal with?


mgb260
Jim Nichols
Sequim,WA
(2120 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 2 bar with diagonal bar, coilover rear supension
Posted by: mgb260
Date: January 09, 2014 02:13AM

I kind of like the Johnny joints instead of rod ends or heims. You could do upper A frame like used in the Dax De Dion setup. Kind of like the old street rod split wishbone design but, upper links, opposite of more common triangulated 4 bar.

[www.4wheelparts.com]



Edited 2 time(s). Last edit at 01/09/2014 02:19AM by mgb260.


roverman
Art Gertz
Winchester, CA.
(3149 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: 2 bar with diagonal bar, coilover rear supension
Posted by: roverman
Date: January 09, 2014 11:48AM

Application is approx. 1% drags, 2+% corner burning, with balance street duty. Adjustable instant center, at rear is required. I can squeez a 12" x 28" tire, in the back. 6" travel in back is adequate.Front torsion bar suspension, will need to go. Mustang II crossmember with coilovers, is the plan. Driven 1k miles/yr. ? 540" will be "somewhat" thirsty ? I'm wanting minimum mods with maximum returns, who doesn't ? Thanks all, roverman.



Edited 1 time(s). Last edit at 01/09/2014 12:19PM by roverman.



DiDueColpi
Fred Key
West coast - Canada
(1308 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

authors avatar
Re: 2 bar with diagonal bar, coilover rear supension
Posted by: DiDueColpi
Date: January 10, 2014 01:55AM

I was going to suggest a somewhat pedestrian leaf spring set up for you Art.
It's fiscally responsible, labor sensitive and a low intensity modification.
With a full length track (panhard) bar. It's simple, cheap and surprisingly tuneable.
But then you added "adjustable instant center" so that pretty much means back halving the car.
With a live axle, that requires a four link or better of some sort.
Lots of options out there. Triangulated, diagonal link, modified three link, etc, etc, etc.
Brand name and no name kits for everything.
Let your wallet guide you on this one.
Loose wallet = fast. Tight wallet, generally = ditch.
Cheers
Fred


roverman
Art Gertz
Winchester, CA.
(3149 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: 2 bar with diagonal bar, coilover rear supension
Posted by: roverman
Date: January 10, 2014 11:06AM

Just "maybe", making front pivot centers, height adjustable, will make I.C. adjustable? My college days, are just a fog to me now. Cheers, roverman.


Norm Peterson
Norm Peterson
Eastern Time Zone
(1 posts)

Registered:
01/27/2014 06:10PM

Main British Car:
Mk I Sprite / Mustang GT None yet / 4.6L

authors avatar
Re: 2 bar with diagonal bar, coilover rear supension
Posted by: Norm Peterson
Date: January 27, 2014 06:41PM

From the sounds of it, you have a truck arm suspension, so named for the 1960's pickup trucks that featured it.

If that is the case, it's essentially the same as what's under the NASCAR cup cars. Hotrods To Hell sells a commercial version for hotrods and such. Tech for coping with this should be available, I know it's come up for discussion over at protouring.com before. Or google "Muttstang".

Yes, it wants to bind up, but this can be minimized by careful design. Basically, the two arms MUST be torsionally flexible, so that they will twist, which reduces how effectively 3" or whatever axle tubes become a rear stabilizer bar. Channel section or I-beam shapes are OK. But round, square, or rectangular closed section tubes are not.

Another detail is the chassis end bushings - there needs to be a little compliance there since you have two pivot points trying to act as one, with neither one being at the virtual intersection of the arms where the whole business really wants to rotate about in roll.

Well done up, it's actually a better arrangement than it appears to be from an 'articulation' point of view. Stable, with no surprises, as most anybody who has driven most any NASCAR driving experience will attest. Considering the fact that you're driving somebody else's car that you've never been in before at speeds well over 100 mph with real concrete walls nearby, they'd have to be pretty confident that this arrangement would be easy for most anybody to drive. At least in 3400-ish lb cars it is. In something half a ton lighter, I'm guessing perhaps not as nice.


Norm


roverman
Art Gertz
Winchester, CA.
(3149 posts)

Registered:
04/24/2009 11:02AM

Main British Car:
74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L

Re: 2 bar with diagonal bar, coilover rear supension
Posted by: roverman
Date: January 27, 2014 07:14PM

Similar to truck arm/ladder bar,(1 each side). One way would point the front pivots of bars,inward, similar to GM truck arms/nascar. Tie the fore/aft loads to existing subframe connectors. Tune the lateral bite, with adjustable panhard bar. Deleting oem K member, torsion bars, stamped a-arms, spindles and brakes. Replacing with current tech. upgrades, with approx. 200 lbs less weight. Onward, roverman.


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