Modified A body Chassis

[clu269]

Here is a customer car we are working on currently.

Where are you located?

[Nothingface5384]

3 link is better at everything compared to a 4 link Eve. With all spherical ends..
With except of 4 link being stronger for drag

For best overall rear suspension torque arm hands down 3 link of still rated over tri 4
More Road race 3 link
More drag tri 4link

[clu269]

Thanks for your input. Does anyone make a torque arm setup that will weld in or that I can modify to work

[raustinss]

I'm pretty sure Chris Alston does

[BMR Sales]

Thanks for your input. Does anyone make a torque arm setup that will weld in or that I can modify to work

You can make anything fit with enough elbow grease! Not sure why you would want a Torque Arm in an A-Body though

[clu269]

You can make anything fit with enough elbow grease! Not sure why you would want a Torque Arm in an A-Body though

I get it. there are so many deafferenting opinions. I am looking for guidance and help in choosing the best option.

[raustinss]

The best aka easiest .. stick with the stock chassis , reinforce it with one of the 3-4 companies that make kits . Then use one of a bunch of companies suspension using the stock style triangulated 4 link . Again it might not be "the best " but you can pull a hair over a g on a skid pad with the right set up in these a bodies

- - - Updated - - -

Or go nuts and use a dobbertinperformance corvette IRS kit

[BMR Sales]

I get it. there are so many deafferenting opinions. I am looking for guidance and help in choosing the best option.

What I was getting at is that in an A-Body, you already have a 4 Link set-up that can be upgraded. a Torque Arm would defeat the purpose of the 4 link and bind everything in a ball!

A Body 4 Link



F Body Torque Arm

[clu269]

The best aka easiest .. stick with the stock chassis , reinforce it with one of the 3-4 companies that make kits . Then use one of a bunch of companies suspension using the stock style triangulated 4 link . Again it might not be "the best " but you can pull a hair over a g on a skid pad with the right set up in these a bodies

- - - Updated - - -

Or go nuts and use a dobbertinperformance corvette IRS kit

I already have the following for my frame.
AFX 1" drop spindles
SPC upper and lower control arms
Speed tech chicane kit
ride tech coil overs
6 piston baer 6P brakes
HPI frame stiffing kit.
I will be narrowing the rear and the frame kit id modified to connect to the rear lower control are cross tube to tie everything together.
If I can compete with the triangulated setup that is a plus. I just want to get the most out of the stock frame since I have the access to lasers, water jet and press brakes to fab anything I design on solidworks.

[jetmech442]

I already have the following for my frame.
AFX 1" drop spindles
SPC upper and lower control arms
Speed tech chicane kit
ride tech coil overs
6 piston baer 6P brakes
HPI frame stiffing kit.
I will be narrowing the rear and the frame kit id modified to connect to the rear lower control are cross tube to tie everything together.
If I can compete with the triangulated setup that is a plus. I just want to get the most out of the stock frame since I have the access to lasers, water jet and press brakes to fab anything I design on solidworks.

I had two major issues with the triangulated 4, which were resolved by the 3 link. The most important at the time was lateral movement of the axle because my tires would rub. As I got serious with the front suspension/brakes, I then noticed that I could never get the car to settle into a corner in time because the rear would oscillate several times until it damped out. It causes uncertainty in corners because the front will have planted happily, but the rear will still be moving mid corner, changing the loading on the tires. this cannot be fixed with solid(or poly bushings) in the uppers. The uppers need to have compliant bushings in order for the axle to roll without binding. The lowers shouldn't be solid for the same reason and in design shouldn't be accepting lateral load anyways-so this issue is inherent to the design of the Tri4. this doesn't really matter in a drag cause, you know, straight lines.

The other major issue is that Rear Roll center and Anti squat are directly coupled. Lowering rear roll center for a more balanced roll axis directly moves your Anti squat lower. In A bodies that have been lowered, the the upper arms angle down and increase antisquat. But this puts the roll center point into the trunk(with my edelbrock antisquat relocation bars, the roll center was actually near the torsion bar for the trunk lid. I've found the car is very stable and predictable when the roll center is about an inch above the axle centerline. Ina 4 link car that would mean the upper arms are angled upward(towards the front) and antisquat is, i don't really know at that point..zero? I'm not good enough to know, but I know I don't want whatever it is lol).

This is getting long,and I don't want to take up space on your thread if its not helpful, so I"ll just say that a watts or panhad bar can overcome the issues above -Almost-. I ran the watts for about a year with the Tri4. It completely eliminates the side to side movement, and lets you choose the rear roll center. Yes, I had two rear roll centers. 1 Physical(watts) and 1 virtual(Tri4 upper arms). the Watts wins right up until the uppers go into bind-then things get unpleasant. the settings to get into bind are not where I would normally run it, and if you keep the rear reaally stiff and damped, the axle won't move up and down enough to matter...but I wanted freedom to explore a wide variety of setups and the ability to quickly alter antisquat as well, so that led me to the 3 link. hope this helps, let me know if you have any questions.

[raustinss]

If you already have all of this make me an offer for my abc performance mini tub kit then replace the stock components with an engineered rear set up. Unless your dead set on wanting the absolute best stuff out there . At the end of the day a properly designed rear 4 link will give you damn near everything you want . I believe this has all turned into a giant pissing match ... aka the difference between a 500 whp engine vs a 650 whp. End of the day you're going to get everything you want and can actually use with 500 whp but , yes we all want to say we have 650 whp if you follow me

[clu269]

I had two major issues with the triangulated 4, which were resolved by the 3 link. The most important at the time was lateral movement of the axle because my tires would rub. As I got serious with the front suspension/brakes, I then noticed that I could never get the car to settle into a corner in time because the rear would oscillate several times until it damped out. It causes uncertainty in corners because the front will have planted happily, but the rear will still be moving mid corner, changing the loading on the tires. this cannot be fixed with solid(or poly bushings) in the uppers. The uppers need to have compliant bushings in order for the axle to roll without binding. The lowers shouldn't be solid for the same reason and in design shouldn't be accepting lateral load anyways-so this issue is inherent to the design of the Tri4. this doesn't really matter in a drag cause, you know, straight lines.

The other major issue is that Rear Roll center and Anti squat are directly coupled. Lowering rear roll center for a more balanced roll axis directly moves your Anti squat lower. In A bodies that have been lowered, the the upper arms angle down and increase antisquat. But this puts the roll center point into the trunk(with my edelbrock antisquat relocation bars, the roll center was actually near the torsion bar for the trunk lid. I've found the car is very stable and predictable when the roll center is about an inch above the axle centerline. Ina 4 link car that would mean the upper arms are angled upward(towards the front) and antisquat is, i don't really know at that point..zero? I'm not good enough to know, but I know I don't want whatever it is lol).

This is getting long,and I don't want to take up space on your thread if its not helpful, so I"ll just say that a watts or panhad bar can overcome the issues above -Almost-. I ran the watts for about a year with the Tri4. It completely eliminates the side to side movement, and lets you choose the rear roll center. Yes, I had two rear roll centers. 1 Physical(watts) and 1 virtual(Tri4 upper arms). the Watts wins right up until the uppers go into bind-then things get unpleasant. the settings to get into bind are not where I would normally run it, and if you keep the rear reaally stiff and damped, the axle won't move up and down enough to matter...but I wanted freedom to explore a wide variety of setups and the ability to quickly alter antisquat as well, so that led me to the 3 link. hope this helps, let me know if you have any questions.

This is excellent and make me want to move to the 3 link. I will be working on the Chassis in the next month and send you photos to critique as I go. You have spent the time guiding me to an outcome that took you possible years to come to. That is valuable and extremely unselfish.
Thanks for you honesty and forthcoming.

[clu269]

PM me on the mini tub kit. That maybe valuable I will research it since I have yet to look into this. I had planed on modifying my stock tubes.
There was certainly no intent for a pissing match. I am only looking to inquire knowledge.
Thanks for the offer on tubes.

[clu269]

I have finally made some progress. I have mocked up the ride height and got the frame kit installed. Frame rails are tacked and ready to install. the lower control arms will be mounted in the rear frame rails.

[raustinss]

Nice work

[Mark@lateral-dynamics]

Interesting rear frame rails! Did you have those cut special, or does someone offer them for sale? We have a 65 El Camino that is going under the knife, probably not terribly soon but this is the main thing we are after too - much larger rear tires (well, front too.).

[clu269]

Interesting rear frame rails! Did you have those cut special, or does someone offer them for sale? We have a 65 El Camino that is going under the knife, probably not terribly soon but this is the main thing we are after too - much larger rear tires (well, front too.).

I actually made a template and traced them out on 11ga plate. i cut them out with a cutoff wheel and lasered out 11ga x 1.75 plate to achieve the 2" width. i would be willing to trace out the rails if you would like.

[chevelletiger]

Nice fab work!!

[clu269]

Nice fab work!!

Thanks I hope to have the chassis mocked up and sitting complete this winter. It take longer than expected when you continue to rethink the build lol.

[Mark@lateral-dynamics]

i would be willing to trace out the rails if you would like.

Hey, I'll take you up on that! Love the project, keep us updated!