Cadillac’s first-ever major Formula 1 upgrade package has broken cover at the Miami Grand Prix.

It is expected to yield a significant step forward in terms of performance given the car spec used early in the year was signed off well in advance with only minor changes.

A new floor is the centrepiece, but there are changes throughout the car both aerodynamically and mechanically.

The upgrades summary issued by the FIA, which addresses aerodynamic geometry changes but not mechanical developments, lists nine separate upgrades for Cadillac - front wing endplate, front wing flap, mirror stay, forward floorboard, floor body, diffuser, rear suspension, rear corner and exhaust tailpipe bracket (below).

“We’ve got a fairly substantial upgrade package, it’s spread over different areas of the car,” said Lowdon when asked by The Race what the team expected.

“Probably the main area is the floor, but there's also changes on front and rear brake drums, front wing as well and lots of bits spread all over the car. It's a mixture of aero and a bit of weight saving as well.

“It's reasonably sizeable, but of course the problem is we don't know what everyone else is doing, so the only thing that makes any difference is that relative delta.

"But we're reasonably hopeful, it's never ideal when you have a fairly substantial upgrade package and it's a sprint weekend because you don't really have an awful lot of time to analyse it, but there should be enough, and with the slightly longer FP1 session (extended to 90 minutes), it should be, so we're reasonably hopeful.”

Cadillac always planned for a significant upgrade for this event, although the unexpected cancellation of the Bahrain and Saudi Arabian Grands Prix has allowed greater time to prepare in terms of fitting parts to the car and also rig testing.

“We weren't focused on operating two grands prix and we could focus a bit more on things like pre-fitting components, which might sound minor but does make a huge difference when you're at the track,” said Lowdon.

“We were also able to do more work on rig testing on the car, so multi-post rig testing, K&C testing (kinematics and compliance, used to test suspension), all that kind of thing, which you normally just don't have time to do because the cars are going from one event to another."

Since pre-season testing, the Cadillac drivers have reported that the car handles well but simply lacks grip thanks to the downforce deficit. As such, the key gain hoped for with the new package is increasing that downforce.

“The biggest weakness we've had is just pure lack of load, aero-wise,” said Bottas when asked by The Race what impact he wants from the upgrade.

“And the biggest portion of this upgrade is just more load, more downforce, in all speed ranges. So that is still the biggest time gain we're going to have. The weight reduction for sure helps, but it's not as big as the deficit we have, aero-wise."

While an upgrade of this type inevitably means that a significant number of new components must be manufactured, Cadillac does have sufficient parts for both cars.

“It’s tight in some areas, there's lots of bits to this upgrade, it's not like a single thing where you've made five of them and you can point at it, there's quite a lot of changes in various areas, which reflects the fact that this is our fourth-ever Grand Prix," said Lowdon.

“So to bring a fairly substantial upgrade package is really encouraging because what you see at the track is the result of everything that's happening back in our multiple locations elsewhere.

“And it's not just about getting a race team operating, it's about getting the manufacturing working, all the processes and procedures, everything from procurement through to in-house manufacture, all of these systems are all completely brand new.

"We'll be watching the performance of the upgrade with great interest because there's an awful lot that we need to verify that other teams will already be well down the route of doing.”