Succesful Steps In Building a A-Body Suspension

[1nkred1ble]

Just make sure you talk to the coilover vendor about drop spindles. Not saying you should or shouldn't use them, just don't assume it doesn't matter. Some factor a drop into the spring itself. So talk to them about it, see what they recommend. Each component you pick can/will have an effect on the others in the system.

I don't think you need drop spindles to fit larger brakes, all it does is move the centerline of the wheel mounting point up 2" vs. stock. Again, talk to the brake guys and suspension guys about what you're looking for, they'll be able to tell you the best way to go.

I got the spindles thru DSE when I got the Baer brakes, don't have p/n or price specs.

If i dont go with the spindle route then how would i be able to throw the big brake system on there??
Is this when a "hub" comes into play???



sorry guys i know its frustrating to hear all these dumb questions

[BobB66SS]

If i dont go with the spindle route then how would i be able to throw the big brake system on there??
Is this when a "hub" comes into play???

No sweat, we've all been there. It sounds like either you're misinterpreting the definition of drop spindle or I missed something about what's on the car now. Let's back up. The part that bolts between the UCA and LCA and that the brakes mount to is the knuckle. The shaft that the bearings and wheel mounting hub slide onto is the spindle. Where that shaft is located on the knuckle is what defines whether it's a stock spindle or a drop spindle. A "2 inch drop spindle" is a knuckle that has the spindle located 2 inches higher than normal; by raising the centerline of the wheel 2", you effectively drop the rest of the car that same distance. Thus the term "drop spindle". Either style will accept a big brake package. Again, talk to the brake supplier of your choice; chances are they'll have both a stock height spindle and drop spindle as options.

If you decide to buy the spindle from a different source than the brakes, you will have to make sure the brakes will fit that spindle. That's why it's easier to get them all from one vendor.

You'll go thru the same thing again when you buy wheels and tires. That/those vendors will need to know your brake and suspension package to make sure the get the size and backspace right to clear the caliper, rotors, sway bar, etc. All of the good ones will know what questions they'll need answers to.

[1nkred1ble]

No sweat, we've all been there. It sounds like either you're misinterpreting the definition of drop spindle or I missed something about what's on the car now. Let's back up. The part that bolts between the UCA and LCA and that the brakes mount to is the knuckle. The shaft that the bearings and wheel mounting hub slide onto is the spindle. Where that shaft is located on the knuckle is what defines whether it's a stock spindle or a drop spindle. A "2 inch drop spindle" is a knuckle that has the spindle located 2 inches higher than normal; by raising the centerline of the wheel 2", you effectively drop the rest of the car that same distance. Thus the term "drop spindle". Either style will accept a big brake package. Again, talk to the brake supplier of your choice; chances are they'll have both a stock height spindle and drop spindle as options.

If you decide to buy the spindle from a different source than the brakes, you will have to make sure the brakes will fit that spindle. That's why it's easier to get them all from one vendor.

You'll go thru the same thing again when you buy wheels and tires. That/those vendors will need to know your brake and suspension package to make sure the get the size and backspace right to clear the caliper, rotors, sway bar, etc. All of the good ones will know what questions they'll need answers to.

Thank you, you just did a woorrllldddddddd of clearing things up for me. I guess I was a little bit confused by youre previous post, when you mentioned your coilover drop spindle setup. I thought you said that you WOULD NOT go with 2 inch drop spindles when using coilovers becuase it would mess up the geometry of your ride.

But now i understand that it is possible to use the drop sinples aslong as i get my spring rate where it needs to be from the manufacturer ( DSE)

Secondly, I currently have the stock 307 SBC in the car that im trying to get started, if im able to accomplish this i dont have to worry about dumping all sort of money in the 454 (that im planning on stroking out to a 496) i have in the garage that needs to be worked up. i.e Instead of spending 2 3 grand on the bb right now i can spend it on the suspension like i am planning to.
My question is with the coilover setup + the 2 inch drop spindle's would it give me enough defecit ( want a real low front end) to order bbc chevy springs on the coilovers because eventually i do plan on going with the bigger motor?
this is the stance i am shooting for.

[Roadbuster]

I have a stance similar to that:


My front crossmember is 3 inches from the ground (between the front tires)

There are several issues with running like this on an A-body.

The driveline angles are one issue that needs to be addressed. You will have to raise the back of the transmission and change the length of the upper rear control arms. If you don't you will have vibrations at highway speeds. This can mean major surgery to the main tunnel to get the clearance. I have adjustable arms which help but I still need to raise the trans. See this thread and this one.

Another is header clearance. Long tubes will more than likely be too low. Shorties will clear or certain brands of long tubes (Doug's for a Pontiac give more clearance) will clear as well. Mine hang down far lower than I would like. Working one issue at a time.

Last is that by lowering the car you raise the rear roll center. This is the opposite of what needs to be done. This is a product of the factory suspension. To correct this you need to change the rear suspension mount points or add a watts link or panhard rod. Still doing my homework here.

Jon

[1nkred1ble]

I have a stance similar to that:


My front crossmember is 3 inches from the ground (between the front tires)

There are several issues with running like this on an A-body.

The driveline angles are one issue that needs to be addressed. You will have to raise the back of the transmission and change the length of the upper rear control arms. If you don't you will have vibrations at highway speeds. This can mean major surgery to the main tunnel to get the clearance. I have adjustable arms which help but I still need to raise the trans. See this thread and this one.

Another is header clearance. Long tubes will more than likely be too low. Shorties will clear or certain brands of long tubes (Doug's for a Pontiac give more clearance) will clear as well. Mine hang down far lower than I would like. Working one issue at a time.

Last is that by lowering the car you raise the rear roll center. This is the opposite of what needs to be done. This is a product of the factory suspension. To correct this you need to change the rear suspension mount points or add a watts link or panhard rod. Still doing my homework here.

Jon

This is the most discouraging bit of information ive received so far. I can barely tie my shoes, how the heck am i supposed to do all that????? I wish i had a 1/8 of your skill & talent. Thanks for your feedback though, now im off to bakers to get a "suspension parts & lingo to english" dictionary.

[C5 Longroof]

Wow....
After reading this thread front to back, I am just amazed at how cool the people on this forum are...

It is just so damn cool of you guys, especially the more experienced suspension guys, to chime in and take the time to break it all down so that it makes sense to a newer builder...I mean, you guys could just throw out some badd ass multi-worded brake lingo and expect a newbie to follow along, and lose patience and flame him when he asks for clarification or a more "basic laymans" answer...

But you guys don't...You reword it without treating him like a third grader, and that is just soooooooo DAMN COOL...Judging by the specific details in some of your answers, there are a few of you guys who really really know their shiznit and quite honestly might have better things to be doing...But here you are, in a newbies thread, taking the time to make sure this guy ends up with a correct understanding of how the suspension actually works and what to do to get his desired results, instead of him walking away with a spinning, blurry head and some parts list of "you gotta buy these items"...

If it don't get said by anybody else, "Thanks for the great, USABLE information"...

Rick

[1nkred1ble]

Wow....
After reading this thread front to back, I am just amazed at how cool the people on this forum are...

It is just so damn cool of you guys, especially the more experienced suspension guys, to chime in and take the time to break it all down so that it makes sense to a newer builder...I mean, you guys could just throw out some badd ass multi-worded brake lingo and expect a newbie to follow along, and lose patience and flame him when he asks for clarification or a more "basic laymans" answer...

But you guys don't...You reword it without treating him like a third grader, and that is just soooooooo DAMN COOL...Judging by the specific details in some of your answers, there are a few of you guys who really really know their shiznit and quite honestly might have better things to be doing...But here you are, in a newbies thread, taking the time to make sure this guy ends up with a correct understanding of how the suspension actually works and what to do to get his desired results, instead of him walking away with a spinning, blurry head and some parts list of "you gotta buy these items"...

If it don't get said by anybody else, "Thanks for the great, USABLE information"...

Rick

SERIOUSLY GUYS THANK YOU SO MUCH FOR YOUR PATIENCE`& WILLINGNESS TO SHARE YOUR WEALTH OF KNOWLEDGE !!!!!

hwystr i coudent say it better myself. Perfectly noted my friend.

[BobB66SS]

I thought you said that you WOULD NOT go with 2 inch drop spindles when using coilovers becuase it would mess up the geometry of your ride.

My question is with the coilover setup + the 2 inch drop spindle's would it give me enough defecit ( want a real low front end) to order bbc chevy springs on the coilovers because eventually i do plan on going with the bigger motor?
this is the stance i am shooting for.

Sounds like we got our wires crossed. What I intended to say is that if you have to choose between dropped spindles and shorter springs, the best way to drop the front end is to include dropped spindles. That retains more of the proper suspension geometry, will make the car much easier to align, and give it better road manners. You can drop the nose by cutting coils off your stock springs (something I would NOT suggest you do) or by using springs that are produced with fewer coils; while this is less expensive to do, like most things you get what you pay for. That way makes the car much tougher to get into proper alignment, with camber or caster settings that give the car poor handling characteristics.

That said, if you have a budget that doesn't allow for coilovers and you're more interested in stand-still stance than road manners, you can still go with shorter springs, you just have to understand the tradeoffs. Like everything else in this hobby, it's a matter of personal choice vs. the $$$ we have available.

In my case I'd said I went with drop spindles a few years ago at the same time I added the Baer brakes. When I added the coilovers a couple years later, the combo of softer coilover springs + 2" drop spindles REALLY dropped the nose of the car. I said in retrospect I may have been able to get away without the drop spindles given how far up I had to adjust the coilovers if I had to choose one over the other. My intent there was to say that you had options to get the stance you wanted, again depending on what matters to you and what $$ you had. Everything costs money, so if it's stance only that you're after, there's a number of ways to get there as noted above. If you want the best shot at good handling, I'd use drop spindles as part of your plan.

I can't say if you can get that low of a stance with a SB motor and BB springs; the coilover vendors are better prepared to answer that one.

As Roadbuster mentioned, try to keep all of your systems in mind when you drop a car that far. You can't get tunnel vision on one system; they all have an effect on other stuff. I like the stance of my car and knew header clearance was going to be an issue. My Hooker header collectors are less than 3" off the ground, and that's after I removed the flanges and used stainless band clamps to make the connection to the rest of the exhaust. That's too low for where/how I drive it. I may have to go to shorty headers at some point, but that also robs power output. And to change headers on my car, the motor has to come back out. Like I said, a change you make one place can have big effects other places.

There will always be some sort of compromise when picking systems out: lower ride height looks cooler and can handle better but can have ground clearance issues; shorter tire aspect ratio (sidewall height) helps handling but can rattle your fillings loose. There's no perfect list of components, they call come with a tradeoff somewhere.

Take your time, decide what matters to you most about the car for the $$ you have to spend, talk to as many people/vendors as you can, and in the end you'll come out fine.

[HWYSTR]

I went through this whole delima myself several years ago, mainly with deciding which route to go on my A-body's suspension. Couple things I want to point out.

First, it's very easy to get carried away, and lose sight of the final config. So, decide once, and see it through.

My 'opinion' on coil overs. It was once explained to me that a coil spring is like a big lever, and the larger the diameter spring, the more linear the rate of the spring. Due to the curb weight of these cars, it only is amplified, not like in a 2500 or so pound race car, in which coil overs work best. There's a ratio in which weight and diameter coil spring is optimum, if you can imagine. So, it is thought by many that the traditional coil spring that came on these cars will track much better than a coil over. My suggestion would be to stick with the traditional coil spring. Global West has many years experience in testing spring rates, and I believe they can advise a 'consumer hobbist' very well, not to mention a max-effort corner burner.

Control arms, front, after much looking around, from dealing with ATS, and the fact that Global West designed the control arms around the ATS spindles, AND since ATS developed their' spindles for improved suspension geometry, I believe the Global West upper and lower control arms with ATS spindles is about as good as it gets, within a reasonable cost. This as all know allows the use of C5/6 brakes, another bonus.

Rear control arms, since the front GWs were selected, makes the rear selection easy in my opinion, GW again, and the spherical bushings/del-a-lum setup is second to none when it comes to articulation.

Lowering. The front driveline angles won't change when you lower the front, only the back will, and that can be corrected easily with the adjustable uppers. If the Instant Center or Roll Center is a concern, you could add the Metco Instance Center Mod brackets or similar. (I believe GW has addressed the RC issue, call them). If you really need to, you could lift the rear of the trans to improve driveline angles, and the amount you can would be dependant on the trans and body bushings used. As a reference, on my A-body, TH-400, 12-bolt, lowered with the GW and ATS 'stuff', I have no driveline vibration at any speed, even above 150mph (high driveshaft RPMs).

Roadbuster - Sweet ride! LOVE IT!! As for the Doug's being tighter to the body, yes they are, but I have still ground the heck out of mine on the daily driver! I cringe every time too! (Guess going air-borne will do that!). On the McLeod bellhousing, on the 'bird, I trimmed the entire lower lip off to avoid any 'contact', which by the way destroys the bellhousing to block alingment. To a point that you have to replace it. Check over on PY and see how I trimmed it, even cut off the extra starter bulge. And yes, it will still protect you in the event of a clutch/flywheel/etc failure. No, it won't pass SFI, or a strict drag track tech. What's your engine specs on that?

-Mike

http://www.youtube.com/watch?v=R2Od_KQq1ms

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[MrQuick]

If i dont go with the spindle route then how would i be able to throw the big brake system on there??
Is this when a "hub" comes into play???

sorry guys i know its frustrating to hear all these dumb questions

I'd go with the ATS spindle option and sell the Bell's. Bolt on C5-C6 compatible brakes.

Don't even worry about it. All these guys are more than willing to help as long as you can keep up.


vince