2026 Aston Martin Aramco Formula One Team

[edu2703]

[vas_04614]

Andy cowell saying issues need to resolved in press conference, so may not be strong enough at beginning of season engine wise!!

[Badger]

From what I've read, 16:1 at ambient would turn to 17.?:1 at 200C. From there to get to 18.3:1 isn't as much a stretch.

The engine doesn't run at 200C, more like 120C.

Typical temperatures:
- Aluminum pistons: 200–350 °C (crown hotter)
- Cylinder heads (Al): 180–250 °C

Blocks: usually lower

Only in very limited parts of the engine do you see such temperatures. Remember that thermal expansion is a function of all the material, not just some of it. The average temperature is more important than the peaks. Where most of the expansion can take place (where most of the “length” sits) in the con rod and block, the temperatures are significantly lower on average.

[Badger]

Andy cowell saying issues need to resolved in press conference, so may not be strong enough at beginning of season engine wise!!

Quote?

[AR3-GP]

Why is the bottom part blurred?

[TyreSlip]

Andy cowell saying issues need to resolved in press conference, so may not be strong enough at beginning of season engine wise!!

Quote?

I can attest that Andy Cowell said that during the conference. Everyone was vague about the power unit and spoke in terms of platitudes.

[diffuser]

The engine doesn't run at 200C, more like 120C.

Typical temperatures:
- Aluminum pistons: 200–350 °C (crown hotter)
- Cylinder heads (Al): 180–250 °C

Blocks: usually lower

Only in very limited parts of the engine do you see such temperatures. Remember that thermal expansion is a function of all the material, not just some of it. The average temperature is more important than the peaks. Where most of the expansion can take place (where most of the “length” sits) in the con rod and block, the temperatures are significantly lower on average.

1. Typical F1 piston material F1 pistons are not pure aluminum. They are usually:
- Forged aluminum alloy
- Commonly Al–Si (high silicon) or Al–Cu–Mg
- Designed for:
   - Very high temperatures
   - Minimal thermal growth
   - Tight piston-to-bore clearances

Typical coefficient of linear thermal expansion (α)
Depending on alloy and silicon content:
Alloy type	        α (×10⁻⁶ /°C)
-----------------------------------------------
Forged Al-Cu-Mg	        22–23
High-Si Al (12–18% Si)	17–20
Hypereutectic (>18% Si)	15–17

F1 pistons are usually in the 17–19 ×10⁻⁶ /°C range.

Units explained
- The ×10⁻⁶ /°C means the values are in microstrain per degree Celsius
- So:
   - 1 ×10⁻⁶ /°C = 1 µm per meter per °C

Example (aluminum)
Typical forged aluminum alloy:
                𝛼≈18×10⁻⁶  /°𝐶

This means:
- For every 1 °C rise, aluminum grows by:
  - 18 µm per meter
  - 0.018 mm per meter

Practical engine example
If an aluminum piston section is 30 mm tall and heats by 280 °C:
                ΔL=30×18×10⁻⁶ ×280≈0.15 mm

That’s why piston crown growth has a measurable effect on compression ratio.

2. Assumed operating temperatures
Typical F1 piston conditions:
- Cold reference: 20 °C
- Crown temperature: 280–320 °C
- Skirt temperature: 150–220 °C
I’ll calculate for 300 °C crown temperature, which is realistic.
            ΔT=300−20=280°C

3. Linear expansion calculation (piston diameter)
Using α = 18 × 10⁻⁶ /°C:
                    Δ𝐷
                    ---   =  𝛼Δ𝑇
                    𝐷0
             =18×10⁻⁶×280=0.00504
Expected expansion of an F1 aluminum piston at 300 °C
Linear expansion:
- ≈ 0.50% growth
- ≈ 5.0 mm per meter
- ≈ 0.005 mm per mm

Example (typical F1 piston)
For an 80.0 mm bore piston:
                                         ΔD=80×0.00504≈0.40 mm

So the piston crown diameter increases by roughly:
0.35–0.45 mm (depending on alloy and exact temperature)

To estimate the compression ratio (CR) increase from piston thermal expansion, we have to translate piston growth into reduced clearance volume.

Given
- Cold (ambient) compression ratio: 16.0 : 1
- Piston material: forged Al-Si (typical F1)
- Crown temperature: ~300 °C
- Reference temperature: 20 °C

Key relationship
Compression ratio:
                              𝐶𝑅=u]𝑉𝑑+𝑉𝑐[/u]
                                    𝑉𝑐

Where:
- 𝑉𝑑 = displacement volume
- 𝑉𝑐 = clearance volume (TDC)
	​
From this:
        𝑉𝑐=   𝑉𝑑   
             𝐶𝑅−1
At 16:1:
        𝑉𝑐= 𝑉𝑑 
            15

Piston crown growth (axial)
Typical axial CTE ≈ linear CTE
Using:
- 𝛼=18×10⁻⁶/°C
- ΔT=280°C
- Effective crown height ≈ 30 mm (realistic F1 piston)
                                                      Δh=hαΔT
Δh=30×18×10⁻⁶×280≈0.15 mm

Convert height growth to volume change
Assume:
- Bore ≈ 80 mm
- Bore area:
A=π(40)2 ≈ 5027 mm2 

Volume reduction:
ΔVc=AΔh≈5027×0.15≈754 mm3

Effect on compression ratio
Original clearance volume:

𝑉𝑐= 𝑉𝑑 
      15
For an 80 mm bore, ~40 mm stroke cylinder:

Vd​≈201,000 mm3⇒Vc​≈13,400 mm3

New clearance volume:
Vc′​=13,400−754=12,646 mm3

New compression ratio:
CR′=Vd​+Vc′​​≈16.9:1
         Vc′​

[Tommy Cookers]

IIRC
F1 pistons must be one of two FIA-specified 'iron alloys'

[Badger]

Typical temperatures:
- Aluminum pistons: 200–350 °C (crown hotter)
- Cylinder heads (Al): 180–250 °C

Blocks: usually lower

Only in very limited parts of the engine do you see such temperatures. Remember that thermal expansion is a function of all the material, not just some of it. The average temperature is more important than the peaks. Where most of the expansion can take place (where most of the “length” sits) in the con rod and block, the temperatures are significantly lower on average.

1. Typical F1 piston material F1 pistons are not pure aluminum. They are usually:
- Forged aluminum alloy
- Commonly Al–Si (high silicon) or Al–Cu–Mg
- Designed for:
   - Very high temperatures
   - Minimal thermal growth
   - Tight piston-to-bore clearances

Typical coefficient of linear thermal expansion (α)
Depending on alloy and silicon content:
Alloy type	        α (×10⁻⁶ /°C)
-----------------------------------------------
Forged Al-Cu-Mg	        22–23
High-Si Al (12–18% Si)	17–20
Hypereutectic (>18% Si)	15–17

F1 pistons are usually in the 17–19 ×10⁻⁶ /°C range.

Units explained
- The ×10⁻⁶ /°C means the values are in microstrain per degree Celsius
- So:
   - 1 ×10⁻⁶ /°C = 1 µm per meter per °C

Example (aluminum)
Typical forged aluminum alloy:
                𝛼≈18×10⁻⁶  /°𝐶

This means:
- For every 1 °C rise, aluminum grows by:
  - 18 µm per meter
  - 0.018 mm per meter

Practical engine example
If an aluminum piston section is 30 mm tall and heats by 280 °C:
                ΔL=30×18×10⁻⁶ ×280≈0.15 mm

That’s why piston crown growth has a measurable effect on compression ratio.

2. Assumed operating temperatures
Typical F1 piston conditions:
- Cold reference: 20 °C
- Crown temperature: 280–320 °C
- Skirt temperature: 150–220 °C
I’ll calculate for 300 °C crown temperature, which is realistic.
            ΔT=300−20=280°C

3. Linear expansion calculation (piston diameter)
Using α = 18 × 10⁻⁶ /°C:
                    Δ𝐷
                    ---   =  𝛼Δ𝑇
                    𝐷0
             =18×10⁻⁶×280=0.00504
Expected expansion of an F1 aluminum piston at 300 °C
Linear expansion:
- ≈ 0.50% growth
- ≈ 5.0 mm per meter
- ≈ 0.005 mm per mm

Example (typical F1 piston)
For an 80.0 mm bore piston:
                                         ΔD=80×0.00504≈0.40 mm

So the piston crown diameter increases by roughly:
0.35–0.45 mm (depending on alloy and exact temperature)

To estimate the compression ratio (CR) increase from piston thermal expansion, we have to translate piston growth into reduced clearance volume.

Given
- Cold (ambient) compression ratio: 16.0 : 1
- Piston material: forged Al-Si (typical F1)
- Crown temperature: ~300 °C
- Reference temperature: 20 °C

Key relationship
Compression ratio:
                              𝐶𝑅=u]𝑉𝑑+𝑉𝑐[/u]
                                    𝑉𝑐

Where:
- 𝑉𝑑 = displacement volume
- 𝑉𝑐 = clearance volume (TDC)
	​
From this:
        𝑉𝑐=   𝑉𝑑   
             𝐶𝑅−1
At 16:1:
        𝑉𝑐= 𝑉𝑑 
            15

Piston crown growth (axial)
Typical axial CTE ≈ linear CTE
Using:
- 𝛼=18×10−6/°C
- ΔT=280°C
- Effective crown height ≈ 30 mm (realistic F1 piston)
                                                      Δh=hαΔT
Δh=30×18×10−6×280≈0.15 mm

Convert height growth to volume change
Assume:
- Bore ≈ 80 mm
- Bore area:
A=π(40)2 ≈ 5027 mm2

Volume reduction:
ΔVc=AΔh≈5027×0.15≈754 mm3

Effect on compression ratio
Original clearance volume:

𝑉𝑐= 𝑉𝑑 
      15
For an 80 mm bore, ~40 mm stroke cylinder:

Vd​≈201,000 mm3⇒Vc​≈13,400 mm3

New clearance volume:
Vc′​=13,400−754=12,646 mm3

New compression ratio:
CR′=Vd​+Vc′​​≈16.9:1
         Vc′​

I hope that was AI or you just wasted a lot of time. The piston must be made from an iron based alloy. And the con rod can't be aluminium either. Iron based alloys and titanium have less thermal expansion.

Also, you are still using this 280 C number for the entire length of the piston. The average temperature from the top of the head to the skirt is going to be much lower than that.

But yes, with the correct thermal expansion ratios, the correct measurements, and the correct temperatures for each part, you are going to see a meaningful increase in the CR. It's just not enough to get to 18:1 with the materials allowed.

[diffuser]

Not all lost .... The iron alloys specified in the rules include:
- AMS 6487
- 15 CDV6
- 42CrMo4
- X38CrMoV5-3

15CDV6 has a α (×10⁻⁶ /°C) of 11.5–12.5 about 35% lower than aluminum. Also 15CDV6 transfers heat 6 times slower than aluminum, therefore, it will run hotter than aluminum. So where an aluminum piston would run around 300C, a 15CDV6 would be near 360C.

| Material           | Hot CR for 16.0:1 cold CR |
| ------------------ | ------------------------- |
| Aluminum piston    | ~16.9–17.0                |
| 15CDV6 iron piston | ~16.6–16.7                |

It's still something.The regs also have the same restrictions on material for Crankshafts and rods. They do allow titanium for rods.

Cylinder heads and main static structure:
- Aluminum or iron‑based alloys.

Cylinder Head Specific Requirements:
- Only one cylinder head per bank is permitted.
- Each head must be made from a single piece of material (exceptions only for defined inserts).


Pretty much leaves you with monkeying around with aluminum head geometry to increase compression.

[BassVirolla]

Typical temperatures:
- Aluminum pistons: 200–350 °C (crown hotter)
- Cylinder heads (Al): 180–250 °C

Blocks: usually lower

Only in very limited parts of the engine do you see such temperatures. Remember that thermal expansion is a function of all the material, not just some of it. The average temperature is more important than the peaks. Where most of the expansion can take place (where most of the “length” sits) in the con rod and block, the temperatures are significantly lower on average.

1. Typical F1 piston material F1 pistons are not pure aluminum. They are usually:
- Forged aluminum alloy
- Commonly Al–Si (high silicon) or Al–Cu–Mg
- Designed for:
   - Very high temperatures
   - Minimal thermal growth
   - Tight piston-to-bore clearances

Typical coefficient of linear thermal expansion (α)
Depending on alloy and silicon content:
Alloy type	        α (×10⁻⁶ /°C)
-----------------------------------------------
Forged Al-Cu-Mg	        22–23
High-Si Al (12–18% Si)	17–20
Hypereutectic (>18% Si)	15–17

F1 pistons are usually in the 17–19 ×10⁻⁶ /°C range.

Units explained
- The ×10⁻⁶ /°C means the values are in microstrain per degree Celsius
- So:
   - 1 ×10⁻⁶ /°C = 1 µm per meter per °C

Example (aluminum)
Typical forged aluminum alloy:
                𝛼≈18×10⁻⁶  /°𝐶

This means:
- For every 1 °C rise, aluminum grows by:
  - 18 µm per meter
  - 0.018 mm per meter

Practical engine example
If an aluminum piston section is 30 mm tall and heats by 280 °C:
                ΔL=30×18×10⁻⁶ ×280≈0.15 mm

That’s why piston crown growth has a measurable effect on compression ratio.

2. Assumed operating temperatures
Typical F1 piston conditions:
- Cold reference: 20 °C
- Crown temperature: 280–320 °C
- Skirt temperature: 150–220 °C
I’ll calculate for 300 °C crown temperature, which is realistic.
            ΔT=300−20=280°C

3. Linear expansion calculation (piston diameter)
Using α = 18 × 10⁻⁶ /°C:
                    Δ𝐷
                    ---   =  𝛼Δ𝑇
                    𝐷0
             =18×10⁻⁶×280=0.00504
Expected expansion of an F1 aluminum piston at 300 °C
Linear expansion:
- ≈ 0.50% growth
- ≈ 5.0 mm per meter
- ≈ 0.005 mm per mm

Example (typical F1 piston)
For an 80.0 mm bore piston:
                                         ΔD=80×0.00504≈0.40 mm

So the piston crown diameter increases by roughly:
0.35–0.45 mm (depending on alloy and exact temperature)

To estimate the compression ratio (CR) increase from piston thermal expansion, we have to translate piston growth into reduced clearance volume.

Given
- Cold (ambient) compression ratio: 16.0 : 1
- Piston material: forged Al-Si (typical F1)
- Crown temperature: ~300 °C
- Reference temperature: 20 °C

Key relationship
Compression ratio:
                              𝐶𝑅=u]𝑉𝑑+𝑉𝑐[/u]
                                    𝑉𝑐

Where:
- 𝑉𝑑 = displacement volume
- 𝑉𝑐 = clearance volume (TDC)
	​
From this:
        𝑉𝑐=   𝑉𝑑   
             𝐶𝑅−1
At 16:1:
        𝑉𝑐= 𝑉𝑑 
            15

Piston crown growth (axial)
Typical axial CTE ≈ linear CTE
Using:
- 𝛼=18×10⁻⁶/°C
- ΔT=280°C
- Effective crown height ≈ 30 mm (realistic F1 piston)
                                                      Δh=hαΔT
Δh=30×18×10⁻⁶×280≈0.15 mm

Convert height growth to volume change
Assume:
- Bore ≈ 80 mm
- Bore area:
A=π(40)2 ≈ 5027 mm2 

Volume reduction:
ΔVc=AΔh≈5027×0.15≈754 mm3

Effect on compression ratio
Original clearance volume:

𝑉𝑐= 𝑉𝑑 
      15
For an 80 mm bore, ~40 mm stroke cylinder:

Vd​≈201,000 mm3⇒Vc​≈13,400 mm3

New clearance volume:
Vc′​=13,400−754=12,646 mm3

New compression ratio:
CR′=Vd​+Vc′​​≈16.9:1
         Vc′​

Very, very good job.

But still, it is more than probably that there is enough clearance between the piston crown and the cylinder while cold to account for some more mm³ (while I doubt such clearance would be accounted when measuring compression).

By the way, when you put 30mm of crown height you are taking it from the center or from the top of the piston pin?

I continue editing...

0,15mm looks like a lot. Your delta temperature is too big, because the underside of the piston will be nearly at oil temperature.

I would take an intermediate between oil temp (160ºC?) and piston crown (320ºC), getting an average of 240⁰C. Which will give a delta of "just" 220⁰C.

Given the same dilatation coefficient, the very top of the 80mm bore piston would need nearly half a mm of clearance while cold.

At least in street engines, more than 0,1mm is a lot.

[Badger]

Not all lost .... The iron alloys specified in the rules include:
- AMS 6487
- 15 CDV6
- 42CrMo4
- X38CrMoV5-3

15CDV6 has a α (×10⁻⁶ /°C) of 11.5–12.5 about 35% lower than aluminum. Also 15CDV6 transfers heat 6 times slower than aluminum, therefore, it will run hotter than aluminum. So where an aluminum piston would run around 300C, a 15CDV6 would be near 360C.

| Material           | Hot CR for 16.0:1 cold CR |
| ------------------ | ------------------------- |
| Aluminum piston    | ~16.9–17.0                |
| 15CDV6 iron piston | ~16.6–16.7                |

It's still something.The regs also have the same restrictions on material for Crankshafts and rods. They do allow titanium for rods.

Cylinder heads and main static structure:
- Aluminum or iron‑based alloys.

Cylinder Head Specific Requirements:
- Only one cylinder head per bank is permitted.
- Each head must be made from a single piece of material (exceptions only for defined inserts).


Pretty much leaves you with monkeying around with aluminum head geometry to increase compression.

Again, much too high temperature. The expansion is a function of the average temperature across the whole length, not just the highest temperature spot. You'd do better by lowering the temperature and incorporating the con rod and cylinder head in your calculation. Those have more length to expand. I also believe the cylinder head can use aluminium.

The con rod is 120 mm, you can use 30 mm for the piston, and idk what the cylinder head is, at least a few cm. Say the alpha is on average 12 across the whole range, and the average temperature is 120 C.

[AR3-GP]

There is also a reason for the unusual arrangement: "In the discussions with the team, it was emphasized that the packaging should be as short as possible, which is why the arrangement is in two levels. Of course, what you see today is not yet the final specification."

https://www.motorsport-total.com/formel ... n-26012007

[TyreSlip]

There is also a reason for the unusual arrangement: "In the discussions with the team, it was emphasized that the packaging should be as short as possible, which is why the arrangement is in two levels. Of course, what you see today is not yet the final specification."

https://www.motorsport-total.com/formel ... n-26012007

I wished they talked about the battery component during the press conference. This layout is interesting.

[Emag]

There is also a reason for the unusual arrangement: "In the discussions with the team, it was emphasized that the packaging should be as short as possible, which is why the arrangement is in two levels. Of course, what you see today is not yet the final specification."

https://www.motorsport-total.com/formel ... n-26012007

Very interesting. I won't pretend to know what the `best` packaging solution will be aero-wise, but having a shorter unit sounds like a great thing to have in general. Assuming it doesn't come with consequences. Not sure if this has any CoG implications, but the biggest thing that would worry me when you ask for tight packages is reliability.

IIRC, McLaren made similar requirements to Honda when they pulled them back into the sport in 2015. In the end, McLaren got what they wanted. A very tightly packaged and small power unit. However, it was severely underpowered and it also had crippling reliability issues on top of that.
The extra decade of experience Honda has now gives me some confidence we won't have a repeat of that. Whatever compromises they have made, they would have done so with good consideration and I would expect them to have pushed back on some "non-negotiable" requirements for the power unit.

In any case, what they said about knowing they will have some issues with the power unit to start the season, it's not exactly confidence-inspiring. And then again, Alonso somehow ending his career with a problematic Honda engine has a spice of irony in it that sadly befits his career.