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**Benm109** · 09-20-2004, 04:11 PM

Originally posted by Valyndiir

Hello everyone! I did some searching on the forum but could only find a few bits of information that could give me some insight on the questions I have. I an the owner of an 84� Trans Am and I wanted to do some suspension upgrades to it while I rebuild the front end. I have installed a Moser Ford 9� along with a TCI Streetfighter 700-R4. The rear springs/shocks are Eibach Pro Springs and Monroe Sensitrac shocks.

Sounds like a nice set-up you have. Ohh, and welcome to the boards. Don't forget to check out www.thirdgen.org , too. It's dedicated to 3rd gens and is a great site, too, just like this one

I have read that the stamped lower control arms, panhard bar, torque arm, and upper & lower A-arms are relatively weak.

Yep, you're right. The stock stuff can't really handle high horsepower stuff. Oh, and just so you know, 3rd gens don't have upper A-arms.

I also was curious about sway bar kits.

What are you curious about? Bigger sway bars help with cornering. There are tons of companies that make sway bar kits, so just choose one you like.

What �IS- all this stuff?? I am confused as to what the differences are between all of these products, and brands.

Most of the companies that make suspension parts are identical. I would highly recommend Spohn suspension pieces ( www.spohn.net ). The only parts he sells are parts for 3rd and 4th gen F-bodies and many people have bought from Spohn and been very satisfied.

Yeesh. I know the adjustable lower control arms are sort of useless and can only benefit you if you want to use taller tires or something like that. But what is the difference between boxed and tubular. What are the pros and cons of each?

There are always big arguments about which is better, boxed or tubular. Honestly, I have no clue which is technically better. Tubular has always seemed better to me, but I'm no expert on this.

What is the benefit of going with tubular A-arms and are they worth the money?

I think the only benefit of tubular A-arms is less weight on the front end, just like tubular K-members.

The subframe connectors I know I am going to need because the motor I plan to install will hopefully push 450bhp and hopefully similar torque stats.

Even stock 3rd gens need subframe connectors. Every 3rd gen should have SFCs, and this isn't just me talking. They do so much for our cars. You can even install two sets if you want. I recently got done installing mine.

Right now I am looking to upgrade the suspension to a tight cornering system that will be able to handle a good deal of power and actually keep the tires planted. The tubular panhard bars are supposed to help keep the rear end aligned properly under acceleration.

For a tight cornering suspension, I would get lowering springs, a bigger sway bar, polyurethane bushings,and better struts (basically what you mentioned before) for the front. Lower control arms (LCAs), relocation brackets, panhard bar, bigger sway bar, torque arm, better shocks, and polyurethane bushings for the rear. And (don't forget) for the chassis, a strut tower brace, wonderbar A.K.A. steering brace (this piece ties in the front chassis where the front sway bar mounts to), subframe connectors, and maybe a roll cage.

I have heard a �lot- of good things about LCA relocating brackets in helping reduce wheel hop.

They do help, especially if you lower your car at all.

Is an adjustable torque arm any use on the street?

I don't think any adjustable suspension piece is of any use on the street. But with a car/motor like yours, I'm unsure.

How will it drive in wet conditions with these upgrades? This is a daily driver, but I loved the effects the springs and bushings had on the rear end.

The car should drive just fine in the rain, if not better than stock. Although, driving in the rain in a rear wheel drive car with over 400 HP is hard no matter what suspension you have

.

If you have any more questions, just feel free to ask. I can elaborate on anything I wrote, no problem. I can also explain what all of these suspension pieces are for, too. And, once again, welcome!

**Valyndiir** · 09-22-2004, 02:36 AM

Originally posted by Benm109

Sounds like a nice set-up you have. Ohh, and welcome to the boards. Don't forget to check out www.thirdgen.org , too. It's dedicated to 3rd gens and is a great site, too, just like this one

Thanks!

Yep, you're right. The stock stuff can't really handle high horsepower stuff. Oh, and just so you know, 3rd gens don't have upper A-arms.

That is a bit of a relief seeing how most of them were $299!

What are you curious about? Bigger sway bars help with cornering. There are tons of companies that make sway bar kits, so just choose one you like.

Well, one company will say, "omg we use 1 3/4" carbon steel" and then another will say "OMFG WE USE CHROME MOLY SUPER ADAMANTIUM ULTRA METAL STUFF". I would assume chrome moly is better due to it's higher price and that Spohn and other companies use it. (Maybe they are all just STUPID though and want money!

)

Even stock 3rd gens need subframe connectors. Every 3rd gen should have SFCs, and this isn't just me talking. They do so much for our cars. You can even install two sets if you want. I recently got done installing mine.

These give you a frame, correct? Does this help with anything other than preventing your car from warping under hard acceleration? Are there some that are better designed than others? Spohn was the most informative so I am leaning towards them as theirs will have no adverse affects on my set up.

For a tight cornering suspension, I would get lowering springs, a bigger sway bar, polyurethane bushings, and better struts (basically what you mentioned before) for the front. Lower control arms (LCAs), relocation brackets, panhard bar, bigger sway bar, torque arm, better shocks, and polyurethane bushings for the rear. And (don't forget) for the chassis, a strut tower brace, wonderbar A.K.A. steering brace (this piece ties in the front chassis where the front sway bar mounts to), subframe connectors, and maybe a roll cage.

Yes I have seen the wonderbars, but I didn't really consider them. Are they worth it?

I have not searched for a strut tower brace. Didn't look like Spohn had any though...

Also, struts are the shocks in the front� right?? (cough) noclue (cough)

What else do I need to rebuild the front suspension? Ball joints, inner and outer tie rods? Etc...?

Here is what I am up to at this moment. All from Spohn, all chrome moly if they offered it, and OMG they are all red too!!!

Sub-Frame Connectors

Tubular Steering Brace

Spohn Sway Bars Set - Solid 4140 Chrome Moly

Adj. Torque Arm - Trans. Mounted [all they had was adjustable!!]

Panhard Bar - Tubular with Poly Bushings

Lower Control Arm Relocation Brackets - Moser Rear

Lower Control Arms - Tubular with Poly Bushings

Subtotal
*Subtotal: $1,345.00

The strut tower brace I haven't looked for yet, and Global West offers lower A-arms for $199 I believe.

I better be able to spank lamborghinis on the track with this stuff!

**Benm109** · 09-22-2004, 09:15 AM

These give you a frame, correct? Does this help with anything other than preventing your car from warping under hard acceleration? Are there some that are better designed than others? Spohn was the most informative so I am leaning towards them as theirs will have no adverse affects on my set up.

Yes, kind of. Subframe connectors tie in the front and rear subframe of the car (since it's a unibody car), which kinda simulates a full frame car. They help eliminate squeaks, rattles, sagging doors and misaligned T-tops (sometimes), dash rattles, etc. Just to let you know, though, some people feel no difference after getting them, while some people feel a world of difference. But you should definetely get them, though.

There are two basics designs of SFCs, and two different materials used. The two different materials are tubular steel and boxed steel (as I said before, I have no idea which is stronger, but I promise that either will do just fine). The two basic designs are like this: 1. One design connects fron where the tranny crossmember is to the rear subframe (right behind where the LCAs bolt in). 2. The other design connects the front floorboards (I think) to the LCA mounts. Most SFCs are design #2. You can also choose between bolt-in and weld-in SFCs. I personally chose bolt-in because I didn't feel like paying someone to install them and I am a D.I.Y.er and I'm cheap. But, if I were you, I would get some weld-in SFCs, for the strength.

Yes I have seen the wonderbars, but I didn't really consider them. Are they worth it?

Wonderbars, A.K.A. steering braces, help tie in the front of the car. It bolts in under the radiator and also helps with cracking and stress fatigue of the steering system. Steering braces came from the factory on 85-90 IROC-Zs, I believe, but the aftermarket ones are stronger, anyway. I would recommend getting one.

I have not searched for a strut tower brace. Didn't look like Spohn had any though...

Spohn doesn't make any, I don't think, but Edelbrock makes one that is perfect for carb. and TBI (like me) engines. It's probably the best STB since it forms a triangle. The STBs for the TPI cars are just one or two bars that run from one strut tower to the other. You can get the Edelbrock piece at Summit, Jegs, or even some auto parts stores (they have to order it, but it only takes a day for them to ship, instead of Summit or Jegs taking a week).

Also, struts are the shocks in the front� right?? (cough) noclue (cough)

Yeah, pretty much. Struts in the front, shocks in the rear.

What else do I need to rebuild the front suspension? Ball joints, inner and outer tie rods? Etc...?

I can give you a list of what is usually replaced in a front suspension rebuild. I'll have to search for all the stuff. I'll post that a little later.

All of the stuff you posted from Spohn looks good. If you get the Spohn stuff, tubular A-arms, STB, and rebuild the front suspension, your car should definetely be a great handling car. Good luck!

**Injuneer** · 09-22-2004, 10:44 AM

Some random thoughts, hopefully picking up some of the points discussed above.

Determine exactly how you want to use your car.... fantastic corner carver, 1/4-mile king, boulevard cruiser with a good mix of the two. That will determine the path to suspension upgrades.

For example, "lowering" will be compatible with the "corner carver" approach, but could prove detrimental to the 1/4-mile performance. Decide which one is more important.

Carbon steel vs. chrome moly - Generally, both parts will be the same strength. Although chrome moly is stronger in terms of ultimate strength, the manufacturer will generally use a thinner tube wall. That means the carbon steel part and the chrome moly part have the same strength. The advantage now becomes weight savings. The chrome moly is thinner and weighs less. You don't need chrome moly and the weight savings on an LCA. It doesn't weigh that much to begin with. On a roll cage, where you might save 60-80#, its a good idea, IF you can afford it.

Tubular vs. box-section - everyone wants to say "so and so is stronger".... its not as simple as that. which one is "stronger" depends on how the part is loaded, and the actual dimensions of the tube or box. You can't simply say a box is stronger or a tube is stronger, unless you know the kinds of loads it is going to be subjected to. If it takes an torsion load, the answer (and the dimensions) are going to be different than if it takes a simple compression load. Now we're not all "engineers", and even those of us who are aren't about to sit down and design the ideal member section for our specific application. We can let the experts like Steve Spohn design the parts, see what works and copy it. In the case of LCA's, I've seen Spohn's standard carbon steel tubular LCA push a 3,500# 4th Gen to 8.60@160MPH, so I'm pretty sure they will work on my lowly 800HP setup. In general, from the parts I have actually owned or examined, the box-section arms seemed a lot heavier than the equivalent tubular one. My first LCA's were a box-section from Just Suspension. I replaced them with Sphon tubular adjustables for additional tire clearance and less weight.

Adjustable vs. non-adjustable - If you are looking at a high HP application, there are certain parts that should be "adjustable". The torque arm maintains the rear axle assembly's orientation to the drive shaft and trans... something called "pinion angle". You need to increase the pinion angle as HP goes up. In severe cases, you want one pinion angle for the track, and another for the street. Anb adjustable torque arm makes a lot of sense. On the other hand, an adjustable LCA has limited value. As you mentioned, it allows you to position the axle assembly "front-to-back" in the wheel opening.... something that is helpful in fitting 28" slicks into a 4th Gen wheel well, for example (not too sure how tight the 3rd Gen's are). Finally, the panhard rod. The adjustable feature isn't going to cost you too much. That feature allows you to center the body "side-to-side" over the rear axle assembly. Helpful if your car was not built to tight tolerances by the factory, or you are changing the ride height.

Poly ends vs. rod ends - You didn't really ask this question, but eventually, you will need to make a decision on which you want. Poly reduces the "flex" and displacement of the connection. It keeps parts in alignment better. If you have a 1/4-mile car, it helps. With an all-out corner carver, poly can hurt. It can limit the suspension's ability to remain free-moving when the body starts to "roll".... it puts the element, like an LCA in "bind" and can hurt handling. The solution is to use a softer rubber bushing on the body end of the LCA and a harder poly bushing on the axle end. Good for cornering, not as good for straight line performance. Another alternative is to use a "spherical rod end". This is a solid, ball bearing "eye" that the bolt passes through. This eliminate ALL flex, while providing unhindered "rotation".... no suspension bind. But a rod end it expensive (for a good one like Sphon uses), it increases harshness and noise a lot, and it can wear out because of the dusty environment. Rod-ends are good for cornering, and for drag racing, but terrible for a "cruiser".

Sub-frame conectors are valuable. I would not recommend bolt-ons, since they do often bolt through thinner sheet metal, and can "tear" the sheet metal over time. Welding eliminates this problem. Again, both tubular and box-section can work efficiently.

Strut tower brace (STB) - Probably more useful on a 3rd Gen than on a 4th Gen. The 3rd Gen actually uses a true "strut".... the shock is a structural portion of a 3-link mechanism. This is unlike the 4th Gen, where the unequal a-arm suspsension does not rely on the shock for structural strength at all. The loads on the 3rd Gen "strut" top mounting points are more significant than the top mount for the "shock" on the 4th Gens. But there is still the upper a-arm on the 4th Gen (not used in the 3rd Gen "strut" suspension
) that puts lateral loads on the top of the "tower", and can be strengthened with a brace.

Sway bars again are dependant on use. A "cornering" setup wants thicker bars, front and rear. A "drag" car often deletes the front bar and puts a huge bar in the rear to resist body roll on launch. An interesting compromise is to keep your stock sway bars and simply upgrade the bushings and end links to polyurethane..... will make the stock bars respond like a thicker bar.

Hope that covers some of your questions.

**Benm109** · 09-22-2004, 11:46 AM

Thanks for posting that, Injuneer. I was hoping to get some more insight on a couple of issues I brought up. And a second opinion never hurts, either!

**Valyndiir** · 09-23-2004, 12:10 AM

Originally posted by Injuneer

Carbon steel vs. chrome moly - Generally, both parts will be the same strength. Although chrome moly is stronger in terms of ultimate strength, the manufacturer will generally use a thinner tube wall. That means the carbon steel part and the chrome moly part have the same strength. The advantage now becomes weight savings. The chrome moly is thinner and weighs less. You don't need chrome moly and the weight savings on an LCA. It doesn't weigh that much to begin with. On a roll cage, where you might save 60-80#, its a good idea, IF you can afford it.

Should I go with a roll cage for a daily driver?? It seems a bit extreme.

Poly ends vs. rod ends - You didn't really ask this question, but eventually, you will need to make a decision on which you want. Poly reduces the "flex" and displacement of the connection. It keeps parts in alignment better. If you have a 1/4-mile car, it helps. With an all-out corner carver, poly can hurt. It can limit the suspension's ability to remain free-moving when the body starts to "roll".... it puts the element, like an LCA in "bind" and can hurt handling. The solution is to use a softer rubber bushing on the body end of the LCA and a harder poly bushing on the axle end. Good for cornering, not as good for straight line performance. Another alternative is to use a "spherical rod end". This is a solid, ball bearing "eye" that the bolt passes through. This eliminate ALL flex, while providing unhindered "rotation".... no suspension bind. But a rod end it expensive (for a good one like Sphon uses), it increases harshness and noise a lot, and it can wear out because of the dusty environment. Rod-ends are good for cornering, and for drag racing, but terrible for a "cruiser".

Yes, I had not considered it. From what you say rod-ends don't sound like they are going to be very good for my application. The Moser 9" is enough noise for me and the springs are harsh enough. I want something that will last a long time as well. The car will still corner well with poly/poly tubular LCA's right? The stock LCAs I have on there right now are poly/poly and vastly superior to the rubber that was in there. The old bushings may have been just that however, old. Hm, on this note, my stock LCAs with the poly urethane bushings in them seem to squeak a lot. Very annoying! Is it normal for them to squeak? I did not grease them or any of the rear poly bushings for that matter!!... Maybe I should?

Do I have to drop the rear-end to install the LCAs, or do I just jack up the rear and use a pair of jack stands and knock them out? The reason I ask this is because I have never just replaced the LCAs because the LCAs came out when I pulled my POS 10-bolt out to install the Moser.

Sub-frame conectors are valuable. I would not recommend bolt-ons, since they do often bolt through thinner sheet metal, and can "tear" the sheet metal over time. Welding eliminates this problem. Again, both tubular and box-section can work efficiently.

Well, I will be having some exhaust touch-ups after I install these parts so I can have the guys at the shop weld them when I have the exhaust reinforced.

Strut tower brace (STB) - Probably more useful on a 3rd Gen than on a 4th Gen. The 3rd Gen actually uses a true "strut".... the shock is a structural portion of a 3-link mechanism. This is unlike the 4th Gen, where the unequal a-arm suspsension does not rely on the shock for structural strength at all. The loads on the 3rd Gen "strut" top mounting points are more significant than the top mount for the "shock" on the 4th Gens. But there is still the upper a-arm on the 4th Gen (not used in the 3rd Gen "strut" suspension) that puts lateral loads on the top of the "tower", and can be strengthened with a brace.

I am little confused on the benefits of a STB. It reinforces these two points and stiffens the flex caused by hard cornering? This seems like it would have a lot more beneficial effects other than just tightening up cornering.

Sway bars again are dependant on use. A "cornering" setup wants thicker bars, front and rear. A "drag" car often deletes the front bar and puts a huge bar in the rear to resist body roll on launch. An interesting compromise is to keep your stock sway bars and simply upgrade the bushings and end links to polyurethane..... will make the stock bars respond like a thicker bar.

That is a good idea. Sway bar kits are nothing to install, so I will wait on them and see how I like the stock bars with the polyurethane bushings. I must paint them red however!

Another thing, on the swaybar end links, should i tighten those down until the bushings are completely smushed?? I didn't tighten them down all the way because I feared the bushing would squish and tear out.

Hope that covers some of your questions.

Yes, thank you very much!

**beachbum86** · 09-23-2004, 06:23 AM

This was probably the thread that I have read on the board since I have been a member. This was an issue that I was going later on to attack but knew virtually nothing about. You gents have educated me well!!

I do have one quick question because this is about to be an issue that I will face shortly.

For a cornering and handling application, what would be the best tires to use on my stock 15 x 7 wheels? I have junk on there now that was on it when I got the car. They are not going to last to much longer and I want a set of tires that will handle my every so often desire to "drive" my car the way it was designed to be driven.

One more thing to add... The car has the 2.8L TBI V6 and is not that quick, but I still like to give her a little "love" from time to time.

Thanks guys!!

**Dave M** · 09-23-2004, 06:50 AM

Originally posted by beachbum86

This was probably the thread that I have read on the board since I have been a member. This was an issue that I was going later on to attack but knew virtually nothing about. You gents have educated me well!!

I do have one quick question because this is about to be an issue that I will face shortly.

For a cornering and handling application, what would be the best tires to use on my stock 15 x 7 wheels? I have junk on there now that was on it when I got the car. They are not going to last to much longer and I want a set of tires that will handle my every so often desire to "drive" my car the way it was designed to be driven.

One more thing to add... The car has the 2.8L TBI V6 and is not that quick, but I still like to give her a little "love" from time to time.

Thanks guys!!

I'm assuming this is your everyday car and you'll need an all-season tire, correct? Assuming you want to keep the stock 215/65's and not knowing your price range, try this search on tirerack, that way you can find something you like in your price range: http://www.tirerack.com/tires/Compar...e=PAS&x=6&y=12

You can upgrade your rims to 16x8, and choose one of these tires: http://www.tirerack.com/tires/Compar...=PAS&x=13&y=10

And by the way, you 2.8 should be a TPI car, not a TBI. My first car was an 86 2.8 firebird.

**Injuneer** · 09-23-2004, 11:52 AM

Originally posted by Valyndiir

Should I go with a roll cage for a daily driver?? It seems a bit extreme.

You only need a roll "bar" if you race at NHRA tracks (and I'm sure something like SCCA and others - but I don't know their rules), and your car is capable of running quicker than 12.00 seconds in the 1/4-mile (Under 14.00 in a convertible). A "bar" is simply a hoop behind the driver, 2 braces to brace the hoop to the rear of the car, and a single brace on the drivers side to brace the hoop to the front of the car. (NHRA only requires these 5 points) Most people also install the side/front brace on the passenger side, yielding a 6-point design. You can also add diagonal braces from the hoop "legs" to the floor and have an 8-point roll bar.

A "cage" is something a little more complicated - adds a halo over the drivers head from the hoop to the windshield, braces from the halo to the front floor and a brace across the dash to those braces. Typically called a 10-point or 12-point design. A cage is only required on cars running quicker than 10.00 seconds.

I wouldn't put a bar in a street car. It makes entry to the back seat extremely difficult. The sidebar needs to be climbed over to get into the car, unless you use a "swingout" feature. You or your passengers can hit their heads on the bar in an accident. Padding can help, but there is still a risk.

The car will still corner well with poly/poly tubular LCA's right? The stock LCAs I have on there right now are poly/poly and vastly superior to the rubber that was in there. The old bushings may have been just that however, old.

To the average "daily driver" people like most of us, the poly/poly seems to produce good results by improving and holding the location of the rear suspension components. I believe it is primarily at the extreme limits that the "bind" produced by stiff poly bushings becomes an issue. I think the average Auto-X or road bracing buff will tell you not to use poly/poly, but they are running at extreme conditions that you simply aren't even going to try on the street (well, not very often).

Hm, on this note, my stock LCAs with the poly urethane bushings in them seem to squeak a lot. Very annoying! Is it normal for them to squeak? I did not grease them or any of the rear poly bushings for that matter!!... Maybe I should?

ES has a great white grease for their poly bushings. I did their "master kit"... virtually every bushing in the car, front and rear suspension, tranny mount, TA mount, etc. I used huge quantities of the ES grease on the rotating bushings, and 5 years later there are no squeaks in the car's suspension. A few of them have been upgraded to rod ends, so there's not as much poly as there used to be.

Do I have to drop the rear-end to install the LCAs, or do I just jack up the rear and use a pair of jack stands and knock them out? The reason I ask this is because I have never just replaced the LCAs because the LCAs came out when I pulled my POS 10-bolt out to install the Moser.

Jackstands unded the subframes, support the rear axle with a floor jack, and simply unbolt one LCA at a time.

I am little confused on the benefits of a STB. It reinforces these two points and stiffens the flex caused by hard cornering? This seems like it would have a lot more beneficial effects other than just tightening up cornering.

Not sure of how much "real" improvement there is. I have read, from looking at posts on the Auto-X and road racing boards, that serious racers do not all like the STB on the 4th Gen. They claim that it improves handling up to a point, and then causes an extremely sharp change in handling at the break-away point that makes it more difficult to control the car. I have no idea if this is correct. Think about what the front suspension looks like. The lower part of the suspension is carried on a fairly heavy, rigid K-member, that is bolted across the subframes. The bottom end isn't going to "flex". The top of the suspension on the other hand, is bolted to the "towers" that are really just slightly reinforced portions of the sheet metal inner fenders. An upright on each side. The sheet metal may deform under load. The top of the strut (3rd Gens) is held fairly well "front-to-back" by the fender structure being attaced to the cowl. But there is very little "side-to-side" bracing at the top of the towers. The tops of the towers are going to tilt inward under load. The strut brace holds the top apart, and prevents them from moving in and out toward and away from each other as the loads on the front suspension vary. It will reduce body flex (flex eats up energy and fatigues sheet metal) and prevent the suspension geometry from jumping all over the place. You should feel a more stable steering with the STB. I "think" I did.... but its hard to quantify.

Another thing, on the swaybar end links, should i tighten those down until the bushings are completely smushed?? I didn't tighten them down all the way because I feared the bushing would squish and tear out.

Tighten them to torque spec. The poly can probalby take a little more torque than the plain rubber. I can't remember whether ES includes a torque recommendation with their bushing kit or not. You don't want to just "smush them down" as far as they go. You also don't want to put any lube on them, at least according to ES. Same with the shock bushings... tighten to spec, not "as far as they can go".

Bar, with swingout:

Cage (at least a part of it):

3-point shock tower brace:

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