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[240] Show us your Panhard mount relocations

DrZiplok

Member
Joined
Nov 25, 2015
Ok, long shot. Thanks to the folks that commented in my previous thread about RR wheel lifting plus far too much internet self-study time, I think we need to raise the body-side Panhard bar mount point. A lot.

This looks messy. Like it will involve cutting up the existing mount, fabricating things, relocating fuel lines, etc. I would love to learn from others' mistakes.

Have you done this? Did you regret it? What would you do differently? Or was it f'ing awesome? I'd love to know...
 
Ok, long shot. Thanks to the folks that commented in my previous thread about RR wheel lifting plus far too much internet self-study time, I think we need to raise the body-side Panhard bar mount point. A lot.

This looks messy. Like it will involve cutting up the existing mount, fabricating things, relocating fuel lines, etc. I would love to learn from others' mistakes.

Have you done this? Did you regret it? What would you do differently? Or was it f'ing awesome? I'd love to know...

you might be able to just drill another hole 1" up and maybe clearance the mount...but it really depends on (this is what I have been reading as well, so take it with a grain of salt) the type of driving and how big or small of a track youre on.
 
I can't envision what it looks like back there right off the top of my head, but couldn't you raise the mounting point on the rear axle and achieve the same goal of lifting the rear roll center? That would also minimize lateral axle movement by bringing the panhard bar closer to parallel with the ground. Problem with this might be unintended consequences of moving the roll axis.

Is this the budget race car with the Randy Pobst vid and the TruTrac complaint?
 
shoestring said:
Is this the budget race car with the Randy Pobst vid and the TruTrac complaint?

It is.

cwdodson88 said:
Why move it up?

As it stands, it contributes to jacking the RH rear wheel off the ground in RH corners. With the RH wheel in the air, there is a distinct lack of acceleration on corner exit, which inhibits our otherwise absolute domination of the crapcan racing series we compete in.

shoestring said:
I can't envision what it looks like back there right off the top of my head, but couldn't you raise the mounting point on the rear axle and achieve the same goal of lifting the rear roll center? That would also minimize lateral axle movement by bringing the panhard bar closer to parallel with the ground. Problem with this might be unintended consequences of moving the roll axis.

To get the arm back to the same angle, you'd want to lower the mount on the axle end, but now the arm is at a different height relative to the contact patch, so you still end up with different geometry. Also and less important, we'd have to repeat this for our spare axles, which we change slightly more often than our chassis.

overkiller said:
If you're thinking about cutting stuff up I'd go watts link personally.

Is this a thing you've done or seen done (if so, I'd love to see some pictures)? Because really if I was thinking about cutting stuff up without a plan I'd be putting an E46 subframe in the back and going IRS... 8)

RvolvoR said:
you might be able to just drill another hole 1" up and maybe clearance the mount...but it really depends on (this is what I have been reading as well, so take it with a grain of salt) the type of driving and how big or small of a track youre on.

Not circle track. Road racing. I've read all those things, and they're only marginally helpful because we turn both left and right. 1" won't be anything like enough to get back to the original geometry (assuming that was more or less good) given how far we have dumped the rear.

s11lfbQ.png


Still interested in your experiences / suggestions...
 
The reason I asked why, is that its been getting more and more "I read this on the internet" but the person asking the question has no idea why they are wanting to make a change or modify something... With rear axle hiking in one corner vs the other, I don't really feel like moving the roll center up or down is going to change that effect that much. How is the panhard bar currently set? Angled? Chassis side high?

How is the suspension currently limited under droop? When you lift the car and let the axle dangle, does it dangle even? Higher on the chassis mount side or axle mount side?

Going to a watts link could solve this, moving to a watts link with the pivot on the chassis and arms on the axle seemed to work well in a similar regard with my 122, but I was focused on roll center>center of gravity vs roll center>contact patch. The only downfall was space constraints, so usually its easier to place the pivot on the axle.

I would take a look at turnology, they did a few wiriteups on the key differences and the cause:effect of them.

Also, RPM Net did a tech article explaining the typical handling characteristics of a few different panhard locations.
 
Last edited:
Watts:
6919205.jpg


6919207.jpg


Group A 242:
9401834.jpg


Other side, from Anthony Hyde's page:
PK8axlesusp.jpg


http://people.physics.anu.edu.au/~amh110/group_a_volvo_specs.htm
(also note his link to my pbase gallery :lol:
Photos - Pirate site showing a wide variety of nicked GpA pics (how about thanking the contributors))

https://240grupp-a.se/

Another shot of a rear axle, parallel panhard:
then_un1.jpg

From here: https://240grupp-a.se/bengt-thenander/

Another grpA 242 rear axle (full droop, hence not parallel w/axle/ground):
88.jpg

From here: http://240grupp-a.se/sa-byggdes-en-grupp-a-volvo/


More fun pictures to look at:
https://pbase.com/towerymt/240_racing&page=all

Just buy this and dominate:
https://racecarsdirect.com/Advert/Details/86960/volvo-242-turbo-group-a

Not much help...looks like they leave the chassis side alone and move the axle side down.
 
Not circle track. Road racing. I've read all those things, and they're only marginally helpful because we turn both left and right. 1" won't be anything like enough to get back to the original geometry (assuming that was more or less good) given how far we have dumped the rear.

I'm not talking roundy-round. I suggest you read this to study what the effects of moving the panhard around do:

http://lateral-g.net/forums/showthread.php4?t=42568

Also, a few of us have done this style mount (stole pic from hackster), but none of us have tested it yet:
20180813_202512_zpsiqwoonus.jpg
 
If it were me, I would drop the axle side. Ive always wanted to release a bolt on axle bracket to relocate the panhard bar lower, just not enough time to get to it yet.
 
You could also move either of the mounting points inboard to reduce the leverage the panhard has on the RH side of the axle. Alternatively, if you move the body side mount down and/or move the axle side mount up so that the panhard bar is inclined from driver's side to passenger's side, won't that pull down on the RH side of the axle in RH turns? Someone correct me if I'm wrong.
 
You could also move either of the mounting points inboard to reduce the leverage the panhard has on the RH side of the axle. Alternatively, if you move the body side mount down and/or move the axle side mount up so that the panhard bar is inclined from driver's side to passenger's side, won't that pull down on the RH side of the axle in RH turns? Someone correct me if I'm wrong.

Moving the mounting points inboard is bad juju as it will just exacerbate the side to side movement of the axle on articulation.
 
Not much help...looks like they leave the chassis side alone and move the axle side down.

Most likely because Group A cars weren't allowed to move suspension mounting points. If you've got the freedom to move them (which I assume you have in 'crapcan' racing) then do whatever is the most practical.
 
Moving the mounting points inboard is bad juju as it will just exacerbate the side to side movement of the axle on articulation.

but instead of loading R>L tire unequally moving the bar axle mounting location toward the center equalizes the loading between the two tires. It doesnt seem like it would be exacerbating side to side movement of the axle unless its seeing full compression then full droop, that would go through the entire lateral range of the bar. But L high R low articulation would be "free-er" to move about since the locating point is centered.

http://rbmn.free.fr/PL_barre_US.html
 
moving the mounting inwards does make the panhard bar have less jacking forces on the axle but it will create more side to side movement.

Its all a balancing act.

740s use a shorter panhard bar than the 240s and they have a wider axle.
 
Not much help...looks like they leave the chassis side alone and move the axle side down.

On the contrary, that's a ton of help - and thanks, I have been looking for GpA pictures of this part and failing. If it worked for GpA, it ought to work for us.

RvolvoR said:
a few of us have done this style mount (stole pic from hackster), but none of us have tested it yet:

Will definitely be interested to hear about your results, and many thanks for that link - not one I had surfaced and plenty of pertinent material to digest.

blkaplan said:
Ive always wanted to release a bolt on axle bracket to relocate the panhard bar lower

Noted. If you need an excuse to get to it, you know where we are. 8)
 
Its also better to drop the axle side vs the body side because it will help lower the Roll center of the rear.
 
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