[FormulaRedline]

Does anyone know why the coilover suspension disappeared from the Pfadt website? Does anyone know of any other companies manufacturing C7 coilovers?

I feel like replacing the leafs is going to be a must on a competitively tracked car. Not that the leafs don't work, but rather for the ride height, corner balance, and spring rate adjustability. I wonder what issue Pfadt ran into that caused them to pull the item?

 

[weaponX]

I know they're still going to make them, but might not be full production yet. I also have coil overs from another well known mfgr. Are you looking for 2 or 3 way adj? Feel free to email me.

 

[mjw930]

My concern with coil overs with the frame architecture is transferring the load to the top of the frame rail vs. the bottom where the leafs distribute the load. I would need to see and fully understand how the weight is distributed into the frame before I would consider them.

I'm not saying the aftermarket won't engineer a proper solution, I just need to understand them better before I would risk my $60000 car to them.


Sent from my iPad using Corvette Stingray Forum

 

[greggshere]

The car was designed by GM to be a race car built for the track, but street ready. Since the entire car was completely redesigned down to every part and detail, wouldn't the designers have used coil overs if they felt those were the best suspension for the design? Not trying to poo poo on the vendor or coil overs, just trying to understand why GM would not have used them if they are better for the car. Does the Z06 have them?

 

[FormulaRedline]

Gregg, it's a cost of production issue. Adjustable coilovers offer the ability to dial in the suspension beyond anything you would need on a street car (remember this is the racing sub forum). GM wouldn't be able to sell enough volume at a high enough premium to make it profitable, even as an option.

 

[mjw930]

Gregg, it's a cost of production issue. Adjustable coilovers offer the ability to dial in the suspension beyond anything you would need on a street car (remember this is the racing sub forum). GM wouldn't be able to sell enough volume at a high enough premium to make it profitable, even as an option.

Agreed, I think that's a major reason and I feel I need to correct Gregg's assumptions. The C7 was not designed as a race car built for the track but street ready, it's a street car designed to be track ready. Lots of haters around regarding the mono-leaf spring but aside from the lack quick adjustability it has a number of benefits, not the least of which is weight and CG. They do provide a corner balance capability with the parts most use to simply lower the car and with simple modifications to that part you can get both corner weight and height adjustments.

I guess I just don't see the need unless you are building a stripped out track tool. In that case I could possibly see the benefit IF it's properly engineered. I would love to see how they managed it on the frame for the C7.R.

 

[FormulaRedline]

They do provide a corner balance capability with the parts most use to simply lower the car and with simple modifications to that part you can get both corner weight and height adjustments.

I guess I just don't see the need unless you are building a stripped out track tool. In that case I could possibly see the benefit IF it's properly engineered. I would love to see how they managed it on the frame for the C7.R.

Mark, can you tell me more about the corner balancing you are talking about or provide a link in the right direction? I will look into this as well, thanks!

However, I assume this involves swapping parts, and also therefore has discreet settings? The coilovers will allow you to do very precise and continuous ride height adjustments, all without taking the car off the rack/scales. Furthermore, the coilovers also offer an easy way to change spring rates, arguably the thing that is going to most directly impact the handling balance of the car. Finally, the coilovers would make each corner independent instead of the "almost" independent characteristics of the leaf springs.

Obviously not necessary for everyone, but that's why this thread is in this sub forum! Good question on the C7.R, I'll have to go hunting for pictures.

 

[mjw930]

Mark, can you tell me more about the corner balancing you are talking about or provide a link in the right direction? I will look into this as well, thanks!

However, I assume this involves swapping parts, and also therefore has discreet settings? The coilovers will allow you to do very precise and continuous ride height adjustments, all without taking the car off the rack/scales. Furthermore, the coilovers also offer an easy way to change spring rates, arguably the thing that is going to most directly impact the handling balance of the car. Finally, the coilovers would make each corner independent instead of the "almost" independent characteristics of the leaf springs.

Obviously not necessary for everyone, but that's why this thread is in this sub forum! Good question on the C7.R, I'll have to go hunting for pictures.

At the end of each leaf there is a pad on a screw that provides about 1" of travel. That's the pad that engages the lower A arm so moving it up or down changes the ride height on that corner alone. No need to swap out any parts. As for independence, the composite spring (the engineers hate it when you call it a leaf spring) is captured to the lower frame on both sides outboard of the center-line so each side acts completely independent of the other.

In this picture you can see the spring and the adjustment pad

The biggest negative, and reason to go with coil overs is the lack of rate adjustment, something that's as easy as changing springs on a coil over.

 

[FormulaRedline]

At the end of each leaf there is a pad on a screw that provides about 1" of travel. That's the pad that engages the lower A arm so moving it up or down changes the ride height on that corner alone. No need to swap out any parts. As for independence, the composite spring (the engineers hate it when you call it a leaf spring) is captured to the lower frame on both sides outboard of the center-line so each side acts completely independent of the other.

In this picture you can see the spring and the adjustment pad


The biggest negative, and reason to go with coil overs is the lack of rate adjustment, something that's as easy as changing springs on a coil over.

Mark, that picture is perfect, thanks! Is it easy to swap those screws out? Or does the "composite spring" need to be unloaded in some way first (if so, how)?

My understanding was that the mounts mostly captured the composite spring, but at the limits of cornering (i.e. every corner on a race track) there were some dependent effects. Admittedly, however, my understanding is not very robust.

 

[mjw930]

Mark, that picture is perfect, thanks! Is it easy to swap those screws out? Or does the "composite spring" need to be unloaded in some way first (if so, how)?

My understanding was that the mounts mostly captured the composite spring, but at the limits of cornering (i.e. every corner on a race track) there were some dependent effects. Admittedly, however, my understanding is not very robust.

I believe the spring is pretty close to being off weighted when on a lift but I've read where a bottle jack on the spring will push it up enough to allow the "puck" removal. Someone who's done it would be better to answer this question.

It's quite possible that at full corner loading there's some abhorrent behavior but I believe a lot of it is anecdotal and colored by people's pre-concieved notions. For many Coil Overs are considered a requirement though many can't expand on why other than "it's better". The proof is in lap times. Only a side by side comparison or well documented lap times by an individual in a before and after manner would really shed light on just how much it may change performance.

I tend to believe that if it was that much of an improvement they would be part of the Z07 package but that assumes the Corvette team had enough latitude to go that far.

 

[FormulaRedline]

Wow, great article here with details on the suspension:
2014 Chevrolet Corvette Stingray Z51 Suspension Walkaround on Edmunds.com

It also goes into some of the benefits of the leaf springs and their specific setup on this car (e.g. super low weight, and it would seem you can corner balance with the stock setup) as well as their drawbacks (no support for higher spring rates yet, enough cross talk that the base C7 doesn't even run a rear sway bar).