C5 Corvette Suspension Geometry

[BBShark]

I am interested in using C5 control arms, front and rear, on a project car. I would like to find the stock control arm pick up (attachment) points for the C5. Specifically interested in anti-dive angle for the front but could use any info. I do have the stock settings for caster and camber.

[Marcus SC&C]

Unless you`re building a lightweight front mid engine,rear transaxle sports car the C5 geometry will be less than ideal anyway. C5s have super mild camber gain and almost no anti-dive which is fine for a,well balanced lightweight car but less than ideal for the cars we deal with in the PT world. Also bear in mind that GM engineers designed those aluminum arms to be as light as possible and still be strong enough for a light weight sports car with minimal weight transfer under heavy braking etc. Weight was such an overriding concern in the C5 program that the original spindles failed in track testing and had to be beefed up. Also consider that aluminum has a finite fatigue life and that it`s usable lifespan is dramatically reduced if it`s pushed beyond it`s design specs. I`m just sayin. Mark SC&C

[Lowend]

...not to mention that the C5 front upper a-arms are really poorly designed with their pressed in rubber bushings and the 2 mini-cross shafts (for lack of a better way to describe them).
Inherently unstable in stock layout.

https://static1.pt-content.com/images/pt/2008/08/front_upperarm-1.jpg


Works really well in the C5, but I would not design a car around it.

[WS6]

How is it any more unstable than if it had a full cross shaft running through? Or is there more to it than just the minishafts?

[79T/Aman]

two separate mounting points move independently and are not as stable as a cross shaft

[Lowend]

It's not just that...
The "cross stubs" are mounted by being pressed through the rubber bushing from one side to another. This means that the bushing is inherently soft and must be flexible enough to do this.

A few years back I was working with a vendor to develop a del-a-lum bushing for use in a World Challenge C5-R. We could not come up with a good solution for this without using a spherical bearing in the upper a-arm.

Man I miss that car
https://static1.pt-content.com/images/noimg.gif

[WS6]

I see. Thanks for the clarifications.

[BBShark]

Unless you`re building a lightweight front mid engine,rear transaxle sports car the C5 geometry will be less than ideal anyway. C5s have super mild camber gain and almost no anti-dive which is fine for a,well balanced lightweight car but less than ideal for the cars we deal with in the PT world. Also bear in mind that GM engineers designed those aluminum arms to be as light as possible and still be strong enough for a light weight sports car with minimal weight transfer under heavy braking etc. Weight was such an overriding concern in the C5 program that the original spindles failed in track testing and had to be beefed up. Also consider that aluminum has a finite fatigue life and that it`s usable lifespan is dramatically reduced if it`s pushed beyond it`s design specs. I`m just sayin. Mark SC&C

I am considering building a lightweight car for track days. Probably a C3 Corvette body. This would be a stripped car probably about 2800lbs. The suspension components for a C5 and C6 have been around for more than 10 years now and I am unaware of failures of these components due to fatigue. Any information on the C5/6 geometry would be greatly appreciated.

[Marcus SC&C]

There certainly shouldn`t be any problem with fatigue failures on a car lighter than a C5 or C6. Fatigue related failures occur over time and parts like the lower A arms have only been used in non stock applications for a few years. I`m not saying any of them will fail but I`m wary of it because of the reasons stated. Mark SC&C

[JEFFTATE]

Hmmm , Interesting .
So what would work better ?
Global West ?
Detroit Speed ?
SPC ?

[Lowend]

It's really application specific.
In a perfect world you would design a tube frame and chassis and than build the body around it... but the world ain't perfect.

Honestly with a few aftermarket parts the C3 Corvette platform is quite good

[Bjkadron]

I know this is an old thread but I'm also interested if anybody has any info...

I'm building a full tube frame and moving back the engine so My duster wont have a lot of weight on the front(I'm shooting for somewhere around 48/52 f/r ). and I'm lightening it so it will be about 2600-2800# total. So maybe corvette suspension will be right for me? if it is That would save me the time that it would take to design a new system.

thoughts anyone?

[silver69camaro]

It's funny how this thread is bad-mouthing C5/C6 parts. Here's what I think:

1. C6 parts are strong...very strong. I dare anybody here to try and break them. The weight of these pieces go great lengths in helping our cars perform better...and ride nicer.
2. Upper cross shaft movement is extremely minimal in everything except all-out racing applications. NOBODY here will be able to stress these to their limits. NOBODY.
3. The geometry can be easily modified for more anti-dive (not a whole lot is needed), radical camber gain, and still have a fraction of the roll center migration of any modified F-body suspension.

Those who are in the "know" of suspension design understand the C5/C6 design is hard to beat. Right up there with the most exotic Euro cars.

[BBShark]

It's funny how this thread is bad-mouthing C5/C6 parts. Here's what I think:

1. C6 parts are strong...very strong. I dare anybody here to try and break them. The weight of these pieces go great lengths in helping our cars perform better...and ride nicer.
2. Upper cross shaft movement is extremely minimal in everything except all-out racing applications. NOBODY here will be able to stress these to their limits. NOBODY.
3. The geometry can be easily modified for more anti-dive (not a whole lot is needed), radical camber gain, and still have a fraction of the roll center migration of any modified F-body suspension.

Those who are in the "know" of suspension design understand the C5/C6 design is hard to beat. Right up there with the most exotic Euro cars.

I'm glad to hear you say this!

I don't know how this thread turned into the (real or imaginary) inherent weakness of C5/6 suspension components. I asked this question in August looking for the pickup points for a C5/6 suspension. Since then I've been able to locate that information.

[SDMAN]

It's funny how this thread is bad-mouthing C5/C6 parts. Here's what I think:

1. C6 parts are strong...very strong. I dare anybody here to try and break them. The weight of these pieces go great lengths in helping our cars perform better...and ride nicer.
2. Upper cross shaft movement is extremely minimal in everything except all-out racing applications. NOBODY here will be able to stress these to their limits. NOBODY.
3. The geometry can be easily modified for more anti-dive (not a whole lot is needed), radical camber gain, and still have a fraction of the roll center migration of any modified F-body suspension.

Those who are in the "know" of suspension design understand the C5/C6 design is hard to beat. Right up there with the most exotic Euro cars.
-----------------------------------------------------------------
Agree 100%. The C5/C6 suspensions are light, strong and have world class geometry. And thats why I had my A/M Max-G frame made with the C5 parts.

[parsonsj]

I'm with Matt. Those parts have impressive amounts of engineering and failure mode analysis behind them.

The only drawback I see is the inability to service the upper balljoint. If the ball joint fails, you have to buy a new upper control arm/upper bj/upright assembly.

The other weak point is the wheel bearing inserts, but the aftermarket has stepped to make durable long lasting bearings. See Steve Rupp's Defender edition thread for more information on that.

jp

[silver69camaro]

The only drawback I see is the inability to service the upper balljoint. If the ball joint fails, you have to buy a new upper control arm/upper bj/upright assembly.



Agreed. Also, in order to remove the hub, you need to disconnect the LBJ. Oops!

BBShark, I have that info. It's not the geometry we use at AME, but the stock pivot points. PM me if you'd like the info.

[WS6]

vansteel makes hubs for the C5/6 that have tapered bearings and are serviceable for anyone wanting a better hub than stock. Their prices are pretty good as well.

Also, there's a J-tool that's specifically designed to pop the ball joints apart and not damage anything. I use it all the time when doing work on C5s. Never an issue putting it back together or taking it apart.

[JMarsa]

vansteel makes hubs for the C5/6 that have tapered bearings and are serviceable for anyone wanting a better hub than stock. Their prices are pretty good as well.

Also, there's a J-tool that's specifically designed to pop the ball joints apart and not damage anything. I use it all the time when doing work on C5s. Never an issue putting it back together or taking it apart.


So your debunking the myth that the spindles are not rebuildable?

--JMarsa

[LateNight72]

If anyone gets bored.

http://www.mae.wmich.edu/faculty/hathaway/classes/ME465/lecture/Lecture%2008-LongWtTrans-Anti%20pJZ.ppt

[Lowend]

Don't get me wrong - I'm not saying that the C5/6 stuff is bad; but if I'm starting from scratch there is certainly better stuff for a racecar.
I've raced C5's they are unbelievable for out of the box cars. BUT they are out of the box cars; designed to live for 200K miles and keep grandpa happy with their noise isolation ect. If I'm building an open track car, I'm not looking for those compromises.

[Bjkadron]

I agree that the corvette has some compromises... But does anyone know of a fairly cheap computer program to analyze geometry? because it might be easier on the budget to copy a good suspension than spend a bunch on a program and then build that design. But from scratch is fine with me if anyone knows of a cheap program.

[BBShark]

Don't get me wrong - I'm not saying that the C5/6 stuff is bad; but if I'm starting from scratch there is certainly better stuff for a racecar.
I've raced C5's they are unbelievable for out of the box cars. BUT they are out of the box cars; designed to live for 200K miles and keep grandpa happy with their noise isolation ect. If I'm building an open track car, I'm not looking for those compromises.

Again, I am not building a racecar. I am building a car for track days where there is no passing, only a group out on the track trying to get their best out of the car. I'm not even sure if there is a vintage racing class that will allow the use of C5/6 suspension (if there is, it's out of my league financially). I also don't have a ton a money to put into a car that might be used 2 or 3 days a year. So, with this in mind, the C5/6 stuff suits my needs perfectly.

My original post was a request to find the pick up points for a C5/6 as a baseline. I was able to find that in the Suspension Analyzer 2.0 software (2001 Corvette) for others looking for this information.

[Steve1968LS2]

I'm with Matt. Those parts have impressive amounts of engineering and failure mode analysis behind them.

The only drawback I see is the inability to service the upper balljoint. If the ball joint fails, you have to buy a new upper control arm/upper bj/upright assembly.

The other weak point is the wheel bearing inserts, but the aftermarket has stepped to make durable long lasting bearings. See Steve Rupp's Defender edition thread for more information on that.

jp

That's no longer the case. Pfadt now offers an imporved lower ball joint and soon they will have an upper. Just need to be pressed in an out.

There are also new wheel bearing options (from same place) that employ a ZR1 type bearing not subject to the same side-loading problems as the C5/C6 versions.

So, C5/C6 control arms have been one our cars for years now. Anyone every heard of a control arm failing?

[Steve1968LS2]

Don't get me wrong - I'm not saying that the C5/6 stuff is bad; but if I'm starting from scratch there is certainly better stuff for a racecar.
I've raced C5's they are unbelievable for out of the box cars. BUT they are out of the box cars; designed to live for 200K miles and keep grandpa happy with their noise isolation ect. If I'm building an open track car, I'm not looking for those compromises.

Those compromises can be addressed. The bushing issue can be fixed with poly or spherical bearings. Camber can be increased, etc.

But even that's not necessary for the 95% of the people that are never going to drive thier cars at 10/10ths.

Is it the best stuff possible? Heck no, but for "off the shelf" stuff it has a lot going for it.

[Steve1968LS2]

So your debunking the myth that the spindles are not rebuildable?

--JMarsa

The uprights have always been rebuildable. The problem was that GM didn't sell the ball joints seperatly. Also, they take a bit more work since they are pressed in.

But now aftermarket parts are available. As a bonus the parts are better than what GM supplied. I thought I heard someone was selling stock replacements as well.

http://www.pfadtracing.com/catalog/product_info.php/products_id/129

[parsonsj]

Yeah, I asked Jordan if there was any plans for C4 bearings (since my uprights use C4 bearings). Nope.

I guess I'll just plan on replacing them annually. :)

jp

[JMarsa]

Thanks for the info guys!

--JMarsa

[Bjkadron]

[quote=I was able to find that in the Suspension Analyzer 2.0 software (2001 Corvette) for others looking for this information.[/quote]

How much does that program cost? And where can I get it?

[JMarsa]

It has a 30 day trial. Performance Trends is the company, just google the software name.

--JMarsa

[LSfan70s]

My original post was a request to find the pick up points for a C5/6 as a baseline. I was able to find that in the Suspension Analyzer 2.0 software (2001 Corvette) for others looking for this information.

Awesome! Thanks!

[Bjkadron]

Thanks for the info!

[LSfan70s]

Thanks for the info!

Were you able to find the trial? I can not find it.

[LSfan70s]

Were you able to find the trial? I can not find it.

Nevermind. I got it (http://performancetrends.com/programs/Suspension_Analyzer%20v20.exe).

[outlaw 03]

Any word on the pick up points? I'm in the process of gathering info/knowledge on to put C5 stuff under my A body.

[Bjkadron]

click on the "it" in the previous post.. It is the link to the software download with the info on it.

[outlaw 03]

click on the "it" in the previous post.. It is the link to the software download with the info on it.
Thanks.. Above it was mentioned that anti-dive would be needed to make this system work in a heavy car. How do I "analyze" it? My original plan was to use the entire C5 cradle but that puts the motor way too far back. So now I plan on building a "clip" to replace from the firewall forward using C5 arms, spindles & Rack (I got a real good deal on it). I have a lot of Fab experience and but not in properly setting up a suspension from scratch any advise would be much appreciated.

[79PonchoUK]

It's funny how this thread is bad-mouthing C5/C6 parts. Here's what I think:

1. C6 parts are strong...very strong. I dare anybody here to try and break them. The weight of these pieces go great lengths in helping our cars perform better...and ride nicer.
2. Upper cross shaft movement is extremely minimal in everything except all-out racing applications. NOBODY here will be able to stress these to their limits. NOBODY.
3. The geometry can be easily modified for more anti-dive (not a whole lot is needed), radical camber gain, and still have a fraction of the roll center migration of any modified F-body suspension.

Those who are in the "know" of suspension design understand the C5/C6 design is hard to beat. Right up there with the most exotic Euro cars.

Do you consider the transverse leaf a better idea than the traditional coil setups found in most 'exotic' cars?

Considering the advantage of not needing mounting points higher up in the chassis...there must be a notable CofG advantage?? Is the spring lighter than the steel coil equivalent too?

I remember an article over here where a lotus suspension engineer looked at a corvette suspension as part of the article and I believe the remarks were "neat, great design....only problem is that it's expensive". lol

[LSfan70s]

Thanks.. Above it was mentioned that anti-dive would be needed to make this system work in a heavy car. How do I "analyze" it? My original plan was to use the entire C5 cradle but that puts the motor way too far back. So now I plan on building a "clip" to replace from the firewall forward using C5 arms, spindles & Rack (I got a real good deal on it). I have a lot of Fab experience and but not in properly setting up a suspension from scratch any advise would be much appreciated.



This should help clear things up

Instant Centers are where ever two suspension lines cross. Its late so you get a screen shot of the Z6 Z06 chassis unmodified edited in paint after a 16 hour day, no bitching.

#1 is the anti dive (the one I've been really playing with) you can follow the two green lines back to the A frames and see how their pointing. That angle is like the bars on a live axle only they don't move as much as the car squats, remember those 4 points are fixed to the frame they don't travel with the suspension like a solid rear end does

#2 is the anti dive almost the exact opposite of #1 but for the front suspension to keep your front end out of the dirt when you get on the brakes but without needing super huge springs.

https://static1.pt-content.com/images/pt/2010/03/C6_Z06_side_instant_centersJPG-1.jpg

-R^3


That quote gives a good explanation on what we (you, me, all building this kind of thing) are looking for.

I also bought this book that has helped clear things up: Suspension Engineering (http://www.amazon.com/Chassis-Engineering-HP1055-Herb-Adams/dp/1557880557)

Good book :1st:

[silver69camaro]

Do you consider the transverse leaf a better idea than the traditional coil setups found in most 'exotic' cars?

Considering the advantage of not needing mounting points higher up in the chassis...there must be a notable CofG advantage?? Is the spring lighter than the steel coil equivalent too?

I remember an article over here where a lotus suspension engineer looked at a corvette suspension as part of the article and I believe the remarks were "neat, great design....only problem is that it's expensive". lol

I don't really consider it to be a better design, just something different that works within the packaging requirements. The leaf is pretty light, I'd imagine it's probably the same weight as a steel spring, although much less of that weight is unsprung. I think racers swap the leaf for coilovers to make changing spring rates easier.

[outlaw 03]

That quote gives a good explanation on what we (you, me, all building this kind of thing) are looking for.

I also bought this book that has helped clear things up: Suspension Engineering (http://www.amazon.com/Chassis-Engineering-HP1055-Herb-Adams/dp/1557880557)

Good book :1st:

Thanks for the drawing it helps to see pictures. How many degrees of Anti-dive is excessive? I have the Suspension Analyzer 2.0 software. I'm going to start playing with the layout in the picture.

[silver69camaro]

Thanks for the drawing it helps to see pictures. How many degrees of Anti-dive is excessive? I have the Suspension Analyzer 2.0 software. I'm going to start playing with the layout in the picture.

It really depends on your CG height, spring rate, etc. Most suspensions I've set up use anywhere from 2 degrees to about 8, with most being around 6. Too much anti-dive will make the ride harsher than it needs to be, so it's helpful to get it close to optimum.

[Samckitt]

https://static1.pt-content.com/images/pt/2010/03/C6_Z06_side_instant_centersJPG-1.jpg

Anybody have this CADD & willing/able to share it? I assume it is NX CADD data, I have 4 versions of NX & work for the company that makes the software & debating putting a Vette chassis under a Monte SS. This would help EXTREMELY!

[keithq69]

Thanks for posting that picture.
It gives a great relationship between the front and rear suspension.

[Samckitt]

Thanks for posting that picture.
It gives a great relationship between the front and rear suspension.

I copied it from whoever posted it on the first page.

[3R1$C]

Hi there, I am also looking for this CAD. Does anyone have access to it? Happy to pay a small bonus for your time.

[3R1$C]

212594

Reconstructed the angles. Do we have any more information here and the differences to the C5, C7 and C8 chassis? Unfortunately I do not have the other plane.

[3R1$C]

Overlayed the C6 front suspension on the C4 front suspension and found that they are very similar to each other. Almost the same geometry. Any more info on that?

212599