What would be the best pro tour rear suspension?

[williecutlass]

I have 86 Cutlass that I am starting to Pro Tour. I have bought a different frame to start on. I was going to convert the rear over to a Torq arm with a watts link. Just wonder what you guys thought of that.

[cornfedbill]

You cannot go wrong with that set-up as long as it is dialed-in correctly.

Are you planning to buy a kit or build it yourself? Will you be using the stock lower control arm mounting locations?

[williecutlass]

I am planning on doing it all myself. I don't know if I will use the stock lower mounts. I 'm not sure how well they will work.

[Bryce]

I like my 3-link with watts

[cornfedbill]

I am planning on doing it all myself. I don't know if I will use the stock lower mounts. I 'm not sure how well they will work.

Do you have any way to lay it out and run some calculations? The load should not be more than the stock set-up depending on where you tie into the rear axle. You could change to links with spherical rod ends to eliminate the rubber bushings. Just don't use solid bushings that will restrict movement and cause binding.

This sounds like an interesting endeavor. I will be interested to see photos of your progress.

A three link like Bryce has is also a good option. It may cause more cutting on the floorpan than the torque tube, but can be lighter and can perform real well when set up right.

[Rod]

What would be the best pro tour rear suspension?

thats the age old question that keeps driving this site! if you ask 10 guys you get 10 differant answers, I have driven 4links, 3links, leaf spring, truck arm and Independent rear suspension cars and have liked them all each has its own attitude, and its all about the fine tuning on each, at an event last year, I was just as fast on the track driving a 4link car as I was driving a leaf springed car during a driving demo

[bret]

Ultimately...there are better suspension designs than the GM factory 4 link. In reality...that design will outperform MOST drivers, even in a competitive autocross or road course environment. If you are looking for the most bang for your buck [like most of us]...start with some revised front suspension geometry, better tires, better steering box, good shocks, improved seats and steering wheel, and some good front brakes. After you've optimized all those areas, THEN start thinking about revising the rear suspension. As Rodney said, all the various suspension designs feel a bit different...but none of them are THE clear winner. If they were, there would be no question.
As usual...just my opinion.

[williecutlass]

I do plan on 13" front brakes, rack and pinion, after market front control arms, air ride, different front spindles,19x9.5 with a 255-35-19 front 19x11 with 295-35-19 rear wheel tire combo.
I have already replaced the side frame rails with 2x4 rec. tubing and was going to start modding my rear part of the frame.

[MonzaRacer]

Honestly for the cash, the factory style triangulated 4 link with johnny joints and air ride and double or triple adjustable shock would do pretty much anything you want, second choice would be use lower mounted control arms, a third upper link in two parallel uppers and a Fays2 Watts link.
I just dont understand the infatuation with torque arms. That is the one piece of garbage I am TRYING to eliminate from my Monza as it takes up so much real estate AND over stresses the tranny.
Anyway. Try not to let a credit card design your suspension, keep it simple and straight forward.

[MrQuick]

Torque arms are great for ease of installation and packaging.

Other than staying and modifying your 4 link going to a center third link would be very easy. With the proper legnth upper link you will loose some back seat area.

[exwestracer]

Lee, a torque arm probably gives the best compromise between acceleration and braking torque reaction, while still maintaining good rotational freedom for the axle (if designed properly). I'll agree that the factory piece in your Monza is probably junk, designed to be the lowest cost to produce... And they don't stress the trans at all when mounted to a frame crossmember.

As Bret stated, any typical rear suspension design will probably be better than the driver in 90% of situations. Any suspension needs to be correctly engineered and installed, but for a beginning builder, the torque arm eliminates a lot of "figuring out" from the process, with no real down side in performance.

[MonzaRacer]

Ray have you ever seen the torque arm on a Monza? forerunner to the third gen F body and still took aftermarket to keep it remotely useful as the stock crap was pure junk with power. Also under a smaller car it takes up useful room to fit things like , oh say exhaust. After trying to like it, trying to use them I decided to run my yellow Monza with swing arm suspension and then decided after going PT style I will make a bolt in 3or4 link upper mount to do away with it completely and the panhard bar and use a watts link. Why, because its gonna handle better ,take up less critical room and for me, the tuning of it will be so much better than a torque arm. Just cause it can go down road doesnt make it any better. It just makes it functional in SOME cases.
Kind of like 4 link versus ladder bars. Had them both, not BIG fan of ladders as they do go straight ok, tuning and handling, not so good, Took Jegster SS bars to make me rethink trying them again, but again undercar real estate on my car is limited so passing on that.
Kind of like the guy who got on here and bashed Hbody front end design YET I see big name companies selling Mustang II crap as performance. YET thousands buy them and design parts around them, oh and he cut up a car to build a new frame/suspension. Seemed like a waste but then it is his car so he can do what ever. Me I will make minor modifications to make what I have work better. Didnt seem to hurt IMSA Monza's. As the 4 or 5 I have seen had no mods made to the mounting points in front.
Again I may just be jaded, seen too many things made complicated, hard and just plain not built right, too supposedly make it better.

[williecutlass]

All in all I just want to get the best bang for the buck right of the bat. I don't want to put this new frame together and two years latter tear it all out for something that works better. I've done that before. Cost more money in the long run.

[williecutlass]

Just wanted this to go as good as my last build. Here are a couple pics. O yah if anyone has see it around Iowa let me know, had to sell it awhile back. Kind of lost track of it.
70080

[T.K.]

i'm not a fan of the torque arm,but if thats what you want its hard to do it yourself cheaper and as painless as the bmr kit. of course i dont know if they have a kit for the cutlass.

i still think the best bang for the buck is a triangulated four bar and coil overs. no need for a watts or pan hard, saving time and money. you would have to really drive that to feel any of its limitations. honestly you will likely be limited by your non-floating rear before the suspension. id get a full float before i spent more on the pt suspension

[williecutlass]

I am plaining on building a 9 inch. Would you say 4 link is better than a torq arm?

[Rod]

I am plaining on building a 9 inch. Would you say 4 link is better than a torq arm?


:hand:

the answer is whats best for you, I would look at pakaging issues, for example, a DSE 4 link comes thru the floor do you want to cut up your car, ridetech four link fits without cutting but you have to weld on the rear axle, the torque arm is larger and requires extra bracing on the frame and some welding on the frame for a watts or panhard, so whats best for you?

[williecutlass]

Welding and fab. work will not be to much of an issue. I spent 6 months welding up semi trailers and have just spent the last 5 1/2 years as a cnc machinist. I just want to get the PT performance from the get go. Don't want to have to change thing after a few years.

[BMR Sales]

WOW..... not sure where to start. So many good bits of advice and opionions here. We do have alot of Torque Arm experience with 82-02 F-Bodies which is why we came up with a Torque arm to replace the 67-81 F-Body - 68-74 X-Body leaf spring suspensions. We make parts for over 18 different platforms now and we could have easily put together a 4-link or 3 link with a panhard bar, but we decided on a Torque Arm/Watts link for the leaf spring cars.

Now the elephant in the room is do we make or plan to make a Torque Arm for the 64-72 A-Body & 78-88 G-Body cars???? The verdict is still out, but the reason we have not committed to developing a system is will it VASTLY improve the performance of those cars?

I think that although you can experience some binding with the suspension in your car it is a proven performer with the right aftermarket components in place which obviously we manufacture.

[williecutlass]

The torque arm setup seam to work well on the gnx's. Just thought with a little upgrade like the watts link would make it better.

[T-CHRGD]

The torque arm setup seam to work well on the gnx's. Just thought with a little upgrade like the watts link would make it better.

That is the exact set-up I'm planning for my next project car. A modified GNX suspension - rear cover, torque arm, and modified cross brace, but without the panhard bar, and with a watts link.

Just because. :)

[Nothingface5384]

I never new the G-bodies had torque arm kits..figured they just had the same spin-off offerings as our Abodies
not sure if sperical ends johnny/roto/delsphers bind abodies enough to lift tires, but its been proven with pics that they do on G-bodies
gnxray? is his name
which that beeing said DSE kit and even speedtech use swivvel link rear arms to prevent this
not sure how ridetech does, one of the few kits I dont know much about

I def would go with a fay2 watts vs panhard bar if doing a 3-link

[chevelletiger]

Gbodys bind with johnny joints,roto joints etc.?do you have a link to gnxrays pics?

[Nothingface5384]

Gbodys bind with johnny joints,roto joints etc.?do you have a link to gnxrays pics?
I was wrong on the username
its Boosted6 of GNS performance

He posted this on the v8buick board.
Pretty sure he talked about it or someone else mentioned similar situation on here too

85942

I wanna see a G-body with the curry johnnyjoint bushings in axle ear with dual rotos on upper/rotos and see if this still happens..and ofcourse swaybars with ridetechs posilinks to improve the bars articulation

Kind of curious if this is actually the spherical ends on arms not having enough motion or if said swaybar is causing the arms to bind in return lifting the tire in corner

[alphaenvirmgt]

Rack & pinion for g-body will be a challenge for a track car (i.e., not a drag car). The only vendor that I'm aware of is TRZ and I'm told their unit is for drag racing as the ratio is VERY slow. Would not work for autocrossing or similar event. So, you will be on your own designing, fabrication, and installation. If you are up to that, great! Keep me posted! Sounds exciting. I was looking to go where you are headed but ended up purchasing a Lee 600 box and DSE steering shaft.
Conrad

[83hurstguy]

I was wrong on the username
its Boosted6 of GNS performance

He posted this on the v8buick board.
Pretty sure he talked about it or someone else mentioned similar situation on here too

85942

I wanna see a G-body with the curry johnnyjoint bushings in axle ear with dual rotos on upper/rotos and see if this still happens..and ofcourse swaybars with ridetechs posilinks to improve the bars articulation

Kind of curious if this is actually the spherical ends on arms not having enough motion or if said swaybar is causing the arms to bind in return lifting the tire in corner

I find it interesting that lifting the inside tire is attributed solely to Currectracs or roto-joint style rear arms. I've dealt with stock arms, UMI arms and Currectracs and the swivel joint arms will droop a rear end to any limit. There are no "limits" to rotation of the arms for suspension travel. Detroit Speed arms have rubber bushings, which do not rotate but deflect/twist to allow suspension travel. The swivel link takes care of axial twist only. Rubber does bind at its travel limits by design. My experience has been the UMI and Currectrac arms with a swivel joint on one end and poly on the other. You can put a jack under either side with the springs out and put significant inclination on the rear end with minimal effort.

There are some pretty hardcore autocrossers out there with Currectracs (Norm Peterson has them on his S197 Mustang IIRC), and I haven't seen him complain of lifting inside rear tires on a course.

Typically, wheel lifts are indicative of high roll rates and a stiff chassis (look at the front end of a road racing 911). SicMonte (shown in the picture above) has a roll bar in the car, which would stiffen the back half of the chassis. Scot's (boosted6's) car by comparison has no interior roll bar, and may even have stock rubber body bushings. Chassis flex alone could easily make up the difference shown, along with a difference in rear sway bar stiffness.

Here's a picture from ridetech's site of what looks to be a stock suspension A-body going around a corner. Even the junk stock control arms keeps both tires on the ground!

86008

[SicMonte]

Hey that's me!! My rear suspension currently consists of Curr Trac upper and lower arms, stock rubber housing bushings, Spohn Pro Touring bar, and Ridetech coilovers.

My car seems to always lift up the rear tire....even with the bar adjusted to full soft.