How Good Is The Stock Suspension?

[tscott9330]

Alright, I am at that point is the project when I start deciding what to keep and what to trash. I am curious as to everyone opinion on how good the stock suspension and stearing is? (i.e. Front A arms and such) I would also like to lower the 78 just a bit, Just enough to let the aftermarket wheels and tires to fill the wells.

I am on a budget so I would like to keep as much as possible but I also dont want a car that handles like a old cadilac. What are some good upgrades to the suspension that would not brake the bank, but give me a good return on my money?

Also, What is a good way to plant the power at the back wheels? I know how to do it on a solid axle car, but this IRS is a bit perplexing to me.


Tom

 

[AKRAY4PLAY]

VB&P Performance Plus suspension kit. like buying a new C5 with curvey fenders. best $2000 i ever spent. it replaces everything under your car except the spindles, trailing arms, rear diff, power steering ram and half shafts. no modifications except a couple holes drilled in the rear crossmember, just a real nice bolt-on kit. you will be able to adjust spring rate and ride height independantly as well as drop some serious poundage from the car. the new rear camber rods keep the back tires verticle, this aids big time in traction and tire life. keeping the old parts and not cutting the frame help keep resale value high, easy restoration. this is the kit you want, but maybe not the price tag you had in mind. it is worth it! Brian

 

[tscott9330]

Ok, I appreciate the suggestion, but that is a bit rich for my blood. Any other cheaper ideas would be greatly appreciated.

Tom

 

[AKRAY4PLAY]

Tom,
i read in another post you already have a composite rear spring, so go for the VB&P front kit and some rear camber rods. check these out. http://www.vbandp.com/detail.aspx?ID=525
http://www.vbandp.com/detail.aspx?ID=526
these two things should get you what you want. Brian

 

[lone73]

Suspension upgrades

I understand Van Steel is developing a coil-over setup for the front. I think they will be significantly cheaper than $2K. That's what I would go with if it were me.
good luck with it.
.
.

 

[Twin_Turbo]

Okay, someone explain and convince me what the VB&P suspension does to improve the stock suspension? Does it fix problems that the stock suspension have???

I'lll wait for the responses and then I'll gladly give a rundown on what's wrong with the stock suspension and how the VB&P stuff does not fix any of it

B.T.W. Have you driven a C5 and cmpared it to the VB&P setup???

 

[tscott9330]

Ok, turbo I'll bite. I have never even driven a corvette so I am curious as to how it would compare to the suspension of a more moder car, like maybe my 99 mustang GT. If the stock suspension is comparable to my dialy driver then i may leave it stock until I decide I want to get some more cash together. But if the stock suspension rides like a cadillac then I will get some new suspensoin goodies.

Any good feedback here would be appreciated. Maybe a few testimonials from people who have used the stock supension and then upgraded.

And I would like to hear where the stock supension needs improvemnt

Tom

 

[Bob Chadwick]

The ride on the car is no where like a Cadillac. Is it comparable to a C5, not likely. Is it fun to drive, he77 yes.

 

[Last Ride]

Ok, turbo I'll bite. I have never even driven a corvette so I am curious as to how it would compare to the suspension of a more moder car, like maybe my 99 mustang GT. If the stock suspension is comparable to my dialy driver then i may leave it stock until I decide I want to get some more cash together. But if the stock suspension rides like a cadillac then I will get some new suspensoin goodies.

Any good feedback here would be appreciated. Maybe a few testimonials from people who have used the stock supension and then upgraded.

And I would like to hear where the stock supension needs improvemnt

Tom

My wife had a 2000 Mustang. It was only the 6-banger, but my '78 with it's tired stock setup would run circles around that car all day. You have to drive it more, it takes more effort, but it's not an old Cadillac! I would save up the $$$ and try for a ture solution (like the Guldstrand 5-bar kit for the rear). The stock suspension is decent enough for the underpowered stock '78. It's not even that bad for the 1995 LT1 I have in the car now! Of course, the 1991 ZR1 suspension sitting in the garage will be MUCH nicer ...

 

[AKRAY4PLAY]

Okay, someone explain and convince me what the VB&P suspension does to improve the stock suspension? Does it fix problems that the stock suspension have???

I'lll wait for the responses and then I'll gladly give a rundown on what's wrong with the stock suspension and how the VB&P stuff does not fix any of it

B.T.W. Have you driven a C5 and cmpared it to the VB&P setup???

YES!
TT, i am curious to your responce and info. it all depends on what VB&P kit/product you are refering to. i'll agree that replacement coil springs or composite mono-mount springs do nothing to improve the handling. but i disagree with the statement of VB&P does nothing to help the C3's.

let's talk rear-end. stock camber rods are JUNK!! they can't hold an alignment setting, any real power applied and they pull into another position and stay leaving you with tipped in rear tires. they also allow camber "swing" through the travel of the rear tires/suspension. by this, i mean with suspension fully unloaded the tire's tops lean out (looking from rear of car) compared to the bottom, and fully compressed the tops lean in compared to the bottom. this "arc" swing in camber upsets the geometry of the car not to mention take valuable rubber off the road. surface area, aka contact patch, provides traction allowing the whole handling thing to come into play. no traction, no handling. VB&P smart struts replace stock and mount differently. they mount so that the strut and half shaft are parallel. this makes the rear tire travel straight up and down and keep maximum tire on the ground. another benefit is the tie-rod style adjuster. they don't get pulled out of alignment. rear sway bar, most cars never had them, most need them! stock single central mount springs actually rock like a tee-der-todder at the differential. VB&P dual mount eliminates this problem. it is like getting a sway bar without having to install one, then add the sway and bam, no more rear body roll.

alright the front. stock sway bar is a wet noodle, to small for a heavy car. upgrade, many manufacturers make bigger ones. stock a-arms, not bad, heavy but not bad. new a-arms are lighter and stronger, i'll get to the lighter thing later. coil springs work and have so since 1850, upgrade time. coils are heavy and not easily adjustable. your stuck with a spring rate and limited ride height adjustments. the spring pressure is transmitted into the frame in a way that tries to twist the frame rails, hence the transverse stabilizer bars running between the upper a-arms under the hood that a very common on auto-cross Vettes. this force increases frame flex slightly, frame flex = poor handling again. VB&P transmitts the forces into the bottom of the frame under the engine cross member, more of a lifting force instead of a lifting and twisting force. the front dual mount works similarly as described about the rear. there are slight improvements in steering geometry, but hardly worth mentioning. after all the other benefits you won't notice the caster and camber refinements.

now the rest of the rant, sorry this so long fellas!! unsprung weight is bad. anytime you can get rid of it, do it!!!! big rim o-ring tires and aluminum wheels help a bunch. so does dropping a couple pounds off the a-arms and springs. improves the responce time of the acting wheel = improves handling!! dropping weight from car, this is great!! the better your surface area of tire to weight ratio, the higher g-forces are attainable, just look to the Mazda RX7 for an example. light and big treads, possibly the best handling production car, still debatable but impressive.

poly bushing kits instead of squishy rubber that rots away and gives that Cadillac feel, i'll leave that one alone. VB&P comes with all poly for every joint.

finally for now, the ability to adjust your suspension to fit your needs!!! VB&P allows the adjustment of ride height, bonus! it allows the adjustment of spring rate, another bonus!! it allows the independant adjustment of either, without affecting the other, huge bonus!!! adjustments can be made to all four tires in less than half and hour with hand tools and no parts to change, SUPER BONUS!!!!

so in conclusion, i sound like an info-mercial on late night TV. SORRY. but i am just a very satisfied customer with a very good product. i know my $.02 is looking more like a Ben Franklin note, sorry but it is my humble opinion, TT i am looking forward to hearing your ideas on the subject, Brian

 

[Twin_Turbo]

I am talking about all the aftermarket stuff, they all do not address the biggest problem of our front suspension. I'm not sure why you go off like a firecracker man but it sure sounds like you have a personal interest in this, other than being a customer.

I am not saying it does nothing for handling either but I am merely questioning your claim of C5 handling with the VB&P setup. IMO thats BS. No way you can get that kind of handling, even if all the suspension components were up to par the frame is too weak to handle it. It is not just a matter of springs and sway bars, there's a whole lot more to suspension dynamics than that and without a good sturdy base (frame) there's no way to get modern sports can handling.

The biggest problem is the camber curve through the suspension travel, stock the camber gains positibe and this is bad. That's for old tire technology to eliminate the problem of tires running off rims by too large sideways force (neg camber on the insid cornering wheel, the one that goes into bump, gives a larger contact patch)
This is just ancient (50s) technology and it needs to be altered. What ways are there to improve this? A shorter upper arm, a loer upper arm mount or a taller spindle are the possibilities. Does the VB&P or any other suspension upgrade tackle this? NO, only the extended balljoints like those from coleman are a solution (well, more like a bandaid)

There are other problems with the front suspension like the kingpin angle could use a tad more angle, the caster could be a little more (I think the VB&P arms are available with a larger offset on the upper amrs for a few more degrees of camber?), slotted amrs with inserts would be a nice solutiuon.

Then there's the anti dive geometry, I myself would like a little more anti dive so that means moving the rear upper arm mount upwards a little

toe control is dependant on the steering linkage, this is also relatd to the bump steer problem (yes, we have terrible bump steer) so that would give the need for a new centerlink with the tie rod mounts a little further inboard and higher mounted tie rod ball ends (on the outside)

Then there's the VB&P transverse spring, does it fix any of thse problems? NO, I am not saying it's not a nice kit but it does not fix these problems. Also, the spring isstill jsut that a spring and even with he dual mounts it will pass harmonics from side to side since thats what springs do. With the dual mount a some will be cancelled out but there's always harmonics that have a frequency that is not caught by the 2 mounts. A single mount system stops next to no harmonics.

Then there's the sway bar and the spring load, these are just not the answer. A lot of people run a lot of sway bar and heavy springs, what this does is limit the suspension travel, thereby masking all of the problems mentioned above. The best way to make a car handle is to use the softest spring possible, the softest sway bar possible (since sway bar take the independence out of the system) and work around the problems as much as you can with the geometry. If you don't want body roll, just weld the suspension in place at the desired ride height, you won't get any roll at all. will it be comfortable, hell no.

Also, you can install the stiffest springs and sway to overcome problems with geomety but you will run head first into the next poblem, frame flex. Out frames are not torsionally strong at all, they warp like mad, especially the lower arms mounts and the steering box mount frame section. This means that heavier springs will put more strain on the frame, making the chance of cracking or damage to welds much larger.

So, what can be done about body roll to be able to run a softer sway and springs?? Body roll depends on 2 things, center of gravity and roll center. the roll center depends on the instantaneous center of the front susp, the vehicle centerline (on circle track this is offset) and the tire contact patch centerline. A higher roll center gives less body roll, as does a lower CG. So, when we alter the geomrty we can move the CI from outboard (it's there in the stock suspension, that's bad, that's what gives the pos. camber gain) to inboard, giving neg. camber curve and a new pos. for the roll center. The roll center will be above ground in theis place, where it was below or very close to it in stock form. So, we have done a lot of good things, AND we can run softer springs, a softwer sway and have a nice responsive suspension.
Then there's the mentioning of the springs, springs are not completely unsprung, they are partially unsprung most of the time around 50% but it depends on the pos. on the lower arm. The arms are not completely unsprung either, the upper is but the lower isn't

But what the hell are the arms going to accomplish in unsprung weight (are the VB&P arms lighter than stock? Last time I held a set I thought they were heavier) Even if they are lighter and only partially unsprung, theres a heavy hub, a heavy brake rotor and all kinds of other heavy components. The easiest way to lower the unsprung weight is to bolt on alu monoblock type calipers and 2 piece rotors with alu hats (coleman has them, can be custom drilled in any mounting pattern and available with any offset). The VB&P arms are a lot stronger than stock, therefore eliminating flexing, which is always a good thing.

So, now we go to the back. Is camber control the biggest problem in the back? No, not if the C clips are in good shape. The camber curve can indeed be a bit better and that's where the revised bracket and strut rods come in.
You actually want "camber swing"or camber gain, if the inside wheels gains neg. camber and the outside wheel pos. the contact patch to the road stays the largest since the body rolls. The only reason you would not want any camber gain is if theere was abolsutely 0 body roll but there never is, the amount of camber you want to gain is directly related to the amount of body roll.
That's a nice product although I see a problem with long term use and those heim joints. They do not hold up like normal ball joints and the only thing I would be comfortable with would be teflon linered steel joints.

So what is the biggest problem in the rear... TOE control. Because of the single hinge in the trailing arm setup the toe changes as the susp. goes into bump & rebound, the wheel makes an arch. This toe control is the cause of the oversteering sensation in the back under heavy cornering. The only solution here is a C4 type strut suspension or the guldstrand or greenwood setups 9both have huge similarities in design to the C4 setup), not that the C4 stuff is the be all end all, the early years have a jacking problem because of a low roll center. The stock C3 suspension has this jacking problem too.

Then there's the polybushings. Are they nice? YES, are they nice for all the suspension pivots? I feel they are not. One place is the trailing arm front mount, but rubber is not really desireable there too. A spherical bushing would be best there. But, rubber gives and if poly doesn't and is harder to compress than rubber (which it is) it does give one drawback there. Becuase of the toe control the arm does not hinge axially but also sideways and because the poly is harder this will introduce more stress on the arm and the pivot bolt there.

There's a whole lot more, these are just the main points. This suspension is a 1950s design, adding a bucky spring will not fix all the problems.

 

[lone73]

Front monospring...

Howdy ya'll
How 'bout the short version for the reason of it's existence...

I'm guessing here but I think the front monospring was made available to C3 vettes and considered an upgrade by VB a while back because it was the latest thing on the the later model vettes.
I would say lower unsprung weight would be at least one advantage to it. I think that maybe was mentioned back up there somewhere.

Tom,
As far as a suspension upgrade testimonial, my car wallowed in the turns like an old caddy when I bought it. I put 550# springs, KYB gas shocks and a 3/4" rear sway bar on my car not long after I got it. I'm very happy with the handling, corners almost dead flat.
good luck bud
.

 

[XS650]

You can't make a silk purse out of a sows ear and you can't make a C3 handle like a C5.

What you can do is make a C3 handle a whole bunch better than stock. Any American car of that vintage can be significantly improved with out a lot of effort, and greatly improved with more effort.

The first thing to do is decide what you want to accomplish, how much work or money you want to expend and then make a compromise that gives you the best bang for the buck.

A good start is to get the slop out of the suspension by replacing ball joints, take slop out of the steerring with adjustment and good tie rod ends, replace suspension rubber bushings with polyurethane or better, get some good high performance shocks and select anti-roll (sway) bars to balance the car and reduce lean. Good tires too.

Stiffer anti-roll bars work especially well on older cars because by controlling lean they keep the lousy suspension geometry and bump steer from being as much of a problem.

 

[BeaterShark]

Tom, if you want it to handle, make sure those aftermarket wheels are 17". Going from 15" -> 17" with some real tires will make a bigger handling improvement than anything you could buy for $1000 or less for the suspension.

I don't see anything worth the money for the front suspension, other than sway bars.

Oh yeah, the Steeroids rack and pinion (or any home-brew R&P) seems to get big thumbs up from those that have em.

 

[Twin_Turbo]

The steeroids kit has it's shortcomings too, for instance I don't think bump steer was taken into account in the design stage. It's also a rear steer center take off rack which is really more suited to mcPherson type suspensions. Double a arm suspensions call for front steer ETO racks

 

[tscott9330]

well I appreciate all the opinions, and I'm glad someone chimed in with a comparison to a modern car. I rally had no basis for opinion. the only vehicles I have ever driven are a couple of mustngs and a slew of pick up trucks.

I think i'm gonna rebuild the stock supension with quality poly bushings and replace the front springs and get some new shocks all around. some offeset trailing arms, to allow for some wider rear tires are also in the budget. then once i get her looking like a million bucks, i'll invest in what I need based on how the chassis handles the 400 ci engine

Tom

 

[Ganey]

FE-7 hi perf. sus. is very good

How Good Is The Stock Suspension?


Tom

There is an optional FE-7 hi perf. sus. that is very good.
Some info. from my website http://ganeys.home.sprynet.com/77facts.htm
You need a standard of comparison. A good standard of handling is the Road & Track slalom course.
77 sets new record in 77 with 63.6 mph. "hampered by stock air pressures".
Later matched by a Ferrari 512BB.
For reference, Mario Andretti turned63.4 in a 1999 Corvette.