tiranglated 4 link solid rear

[5foot2]

So I'm in the planning stages of a 77 280z. Power is going to be a BBC in the 468cid range with a goal of 450 HP (aluminum heads, intake, water pump, etc will help with the weight). I'm not sure if I'll use a 4L60E or a T56. In the rear I'm not sure if I'll go with an r230 and new shafts/CV joints or a solid axle (9" ford or 8 3/4 mopar).

 

I don't want to run huge tires in back (8"-9", no fender flares), and the car will see far more street time than strip time. If I go the solid axle route, a traditional 4 link seem overkill since it's primary use will be on the street. While I was searching the interweb for chassis stuff I ran across some street rods that used the trianglated 4 link setup. It looks like a nice way to go for a car as small as the Z.

 

Anyone here know about the pros/cons of this type of 4 link? Anyone seens this type of setup on a Z? The one thing I'm worried about is if the Z is to narrow to go this route, but I've not measured anything yet.

 

FYI: The car will have boxed frame rails from the front subframe to the rear with the solid axle, or subframe connectors with the r230 setup. The motor/trans will be plate mounted and I also plan on doing a 4 point bar inside.

[5foot2]

I meant to post this link of this 4 link: http://www.progressiveautomotive.com/triangul.htm

[Pop N Wood]

Not to be an elitist, but sounds to me like you want a 60-70's Chevelle or Nova, not a Z. Would be a much easier starting point than a 280. For example, you are going to have a hard time "boxing" the frame rails on a Z.

 

I don't know the answer to your question about the 4 link.

[johnc]

Triangulated 4 links have bind problems under compression. The old GM 4 link and the current SN95 Mustang chassis are notorious for this problem. It leads to snap oversteer in hard cornering or very bumpy corners because the rear spring rate goes infinite when the angled upper control arms bind and stop all suspension compression.

 

The OEM manufactureres get around this problem by specifying soft rubber bushings in the upper control arm mounts. The suspension example posted appears to use solid upper control arm mounts.

 

Some reference information:

 

http://www.globalwest.net/Mustang_rear_control_arms.htm

http://www.grmotorsports.com/mustanggt.html

http://www.chevyhiperformance.com/techarticles/148_0309_guide/

http://www.carcraft.com/techarticles/116_0302_john/

[5foot2]

I guess if I follow your logic pop-n, everyone else here really wants a vette. Maybe you should read this page: http://hybridz.org/nuke/index.php. Pete Paraska's post pretty much covers it.

 

By boxed frame rails, I was talking about welding in a solid retangular peice of steel tubing from the front subframe to the rear of the car, not "boxing" in the current framing.

[5foot2]

Johnc, thanks for the links. The Currie arms look nice.

[Pop N Wood]

Guess I should be more careful. Didn't mean to offend. But you seemed to be looking for a little more info than just the 4 link setup.

 

Quite a few people have done what you want to do. Look back through some old posts and you will find plenty of info. I do suggest you do a search on stub axles to help you with your rear end question.

 

You might also find quite a number of posts about the whole Z vs. Vette vs. heavy-subframe-solid-rear-axle topic. Some other things you might want to research include unibody vs. subframe vehicles, the handling and streetablity of a well built Z suspension, IRS vs. a solid rear axles, building for HP vs torque (such a low HP BBC with that many cubes will have tremendous torque, especially with narrow tires), the advantages and disadvantages of a big block vs. small block conversion, etc. etc.

 

But it is your car. To each his own. Just offering one man's opinion to help you get what it is you want.

[Michael]

5foot2, The mount locations and bellhousing pattern for the Mark IV BBC are the same as for the Gen I SBC. This makes it possible, in many cases, to swap in the one for the other. As a BBC-Z owner whose car is a perennial garage queen, I would recommend that you build a fairly conventional small-block-powered car first, then worry about structural reinforcement, then worry about rear-end upgrades, and only then consider switching to a big block. Unless, of course, you have extensive experience building big blocks, in which case the cautionary advice is probably misplaced.

 

The consensus on this board is that an R200 differential and stock 280Z rear end components will reliable handle power levels in the 400-hp range, and possibly higher. Variables include tire stickiness, 60'-times, transmission types, etc. Halfshafts are the most common failure item - several vendors on this board offer CV-jointed alternatives, which are often combined with brake upgrades. There are many bolt-in alternatives which would improve rear-end grip and durability, before having to resort to complete suspension surgery.

 

My own car has rather elaborate structural modifications, a 461 cubic inch BBC set 6" further back than the JTR SBC-location (the ultimate limitation is the distributor running into the windshield), a Doug Nash 5-speed gearbox, but completely stock suspension and brakes. Why? Because I plan to phase-in the suspension mods gradually, as the car matures and my needs evolve. The structural reinforcements are insurance for future growth. Bolt-in items can easily be added later. This, I think, justifies postponing the decision to switch from an independent rear suspension to a 4-link.

[Pop N Wood]

Guess I could learn a few things about tact from Micheal.