Renault Power Unit Hardware & Software

[sosic2121]

https://youtu.be/2qtMT85B6vY
I don't know if this has been committed on before, but there is a very interesting sound. I assume it's when waste gates are fully open...

Almost certainly wastegates. Noise occurs at all the right times where extra power would be useful - middle of 3rd gear accelerating out of a corner then 4th and 5th beginning of 6th not in 7th or 8th.

Anyone able to post the speed range - middle of 3rd (say 10k rpm) through to 10k in 6th?

Exactly. Only on the back straight you can hear it in 7th gear.

[henry]

https://youtu.be/2qtMT85B6vY
I don't know if this has been committed on before, but there is a very interesting sound. I assume it's when waste gates are fully open...

Almost certainly wastegates. Noise occurs at all the right times where extra power would be useful - middle of 3rd gear accelerating out of a corner then 4th and 5th beginning of 6th not in 7th or 8th.

Anyone able to post the speed range - middle of 3rd (say 10k rpm) through to 10k in 6th?

From @hollus gearing thread 2017, based on 10400 lower rpm



So around 150kph (traction limit) to 230kph is the range.

[gruntguru]

Thanks Henry. So exactly what you would expect for electric supercharger mode.

[godlameroso]

The secrecy behind the power units this year has been the most frustrating part of F1. Renault Spec C was used for one race, and there's obviously a lot of things that need to get sorted out. Playing detective I have to wonder why Renault has not elected to use a spec C, and why they've been so conservative developing their power unit this year. It's obvious that next year's power unit is based on spec C, we also know that it takes a different installation.

I'm not saying it will or won't be, but rather I wonder if it means an architecture change? Both McLaren and Red Bull have Renault engines, they also both have experience with the Honda engine in it's split turbo guise. I'm sure the Renault engineers have talked with both of their customers, maybe a healthy flow of information guarantees them engine parity, who knows when it comes to internal politics.

There are obviously benefits and drawbacks to both power unit layouts, I wonder if by the end of the power unit regulations, all 4 manufacturers will have converged on the layout.

[Ground Effect]

The secrecy behind the power units this year has been the most frustrating part of F1. Renault Spec C was used for one race, and there's obviously a lot of things that need to get sorted out. Playing detective I have to wonder why Renault has not elected to use a spec C, and why they've been so conservative developing their power unit this year. It's obvious that next year's power unit is based on spec C, we also know that it takes a different installation.

I'm not saying it will or won't be, but rather I wonder if it means an architecture change? Both McLaren and Red Bull have Renault engines, they also both have experience with the Honda engine in it's split turbo guise. I'm sure the Renault engineers have talked with both of their customers, maybe a healthy flow of information guarantees them engine parity, who knows when it comes to internal politics.

There are obviously benefits and drawbacks to both power unit layouts, I wonder if by the end of the power unit regulations, all 4 manufacturers will have converged on the layout.

According to Renault, being in a close fight with Haas for 4th place meant they couldn't risk using C Spec due to it's reliability concerns. But I'm sure they're at least happy to collect data via Red Bull.
Regarding Renault's conservative approach to the PU developments, I've said this before, and it's mere speculation on my part, but I think it's a bit deliberate. Renault are not only behind on the PU compared to Mercedes and Ferrari, but they're also considerably behind on the chassis side to the top 3 as well, as evident by their delta to Red Bull. I think they're in no real rush because of this and would like to have all areas in sync when they plan to fully challenge the top 3. They'll never get recognition from Red Bull, even if they win more races and challenge seriously for the title, it'll will be down to the car, as Red Bull will claim. So for them, I suspect their happy to bide their time with the PU, while they try and catch up on the chassis side. But like I side, I'm only speculating.

[godlameroso]

Renault has mentioned several times that they're fairly confident they'll be far more competitive next year with regards to the power unit. I'm guessing they devoted more resources to the 2019 power unit which is using spec c as a baseline.

[Ground Effect]

Renault has mentioned several times that they're fairly confident they'll be far more competitive next year with regards to the power unit. I'm guessing they devoted more resources to the 2019 power unit which is using spec c as a baseline.

Yes, Cyril touted the gains of the B Spec as being bigger than their current deficit. Remi further said they would make good gains with the C Spec and hope to catch Mercedes and Ferrari completely by 2019. The problem is, all this was said prior to the release of their B Spec, as well the release of their rivals 2nd iteration of their engines. Once all the dust had settled with the releases, Renault expressed surprise by the gains of Ferrari especially. Which gives the impression that they had underestimated the task ahead and overestimated their own developments. The question now is, are they still confident about 2019, or will they still be playing catch up, while still having a significant deficit?

[godlameroso]

Renault has mentioned several times that they're fairly confident they'll be far more competitive next year with regards to the power unit. I'm guessing they devoted more resources to the 2019 power unit which is using spec c as a baseline.

Yes, Cyril touted the gains of the B Spec as being bigger than their current deficit. Remi further said they would make good gains with the C Spec and hope to catch Mercedes and Ferrari completely by 2019. The problem is, all this was said prior to the release of their B Spec, as well the release of their rivals 2nd iteration of their engines. Once all the dust had settled with the releases, Renault expressed surprise by the gains of Ferrari especially. Which gives the impression that they had underestimated the task ahead and overestimated their own developments. The question now is, are they still confident about 2019, or will they still be playing catch up, while still having a significant deficit?

Depends how chummy they get with BP/Petrobras. They have the facilities needed to make the necessary power unit gains in fuel.

[TzeiTzei]

Renault has mentioned several times that they're fairly confident they'll be far more competitive next year with regards to the power unit. I'm guessing they devoted more resources to the 2019 power unit which is using spec c as a baseline.

I think they've said that for years now. And never actually delivered.

[lawnmower]

I don't believe Cyril's words

[Jejking]

Interesting comments by Max Verstappen today.

Verstappen said Red Bull knew it would have to take a penalty and revert to the B-spec Renault engine at some point as the C-spec engine cannot run at high altitude, meaning it would struggle in Mexico, where the track is over 2,000 metres above sea level, and Brazil (over 700 metres).

“Our C-spec cannot run in high altitude in Mexico and Brazil, so we always knew since we took the C-spec on that we had to take another B at one point,” Verstappen said.

Source: https://www.crash.net/f1/news/906221/1/ ... h-altitude

Turbos shouldn't struggle as much on higher altitudes, compared to atmospheric engines. There the power output drops significantly (it's measurable), but with a PU as of today that performance penalty isn't really there. So it's reliability. What parts of the engine suffer more at heights? Could it be that because of cooling thinner air makes for less cooling capacity in the same volume? Not knowing how far Red Bull and Renault have torn up the chassis in the races with C, it could give a clue about airflow requirements.

PS: It worries me that "C" was better in qualifying, but 'only' the same or even slightly worse during the race. But it's a building block for 2019, that's Renaults take on it at least.

[Tommy Cookers]

and turbocharger and H rpm would be higher - the rules limit is 125000
maybe it's ok to design more for the other 19 ? tracks

[63l8qrrfy6]

Was discussed last year - higher turbo/mguh RPM and higher post compressor temperatures due to lower compressor efficiency.

[Godius]

Interesting comments by Max Verstappen today.

Verstappen said Red Bull knew it would have to take a penalty and revert to the B-spec Renault engine at some point as the C-spec engine cannot run at high altitude, meaning it would struggle in Mexico, where the track is over 2,000 metres above sea level, and Brazil (over 700 metres).

“Our C-spec cannot run in high altitude in Mexico and Brazil, so we always knew since we took the C-spec on that we had to take another B at one point,” Verstappen said.

Source: https://www.crash.net/f1/news/906221/1/ ... h-altitude

Turbos shouldn't struggle as much on higher altitudes, compared to atmospheric engines. There the power output drops significantly (it's measurable), but with a PU as of today that performance penalty isn't really there. So it's reliability. What parts of the engine suffer more at heights? Could it be that because of cooling thinner air makes for less cooling capacity in the same volume? Not knowing how far Red Bull and Renault have torn up the chassis in the races with C, it could give a clue about airflow requirements.

PS: It worries me that "C" was better in qualifying, but 'only' the same or even slightly worse during the race. But it's a building block for 2019, that's Renaults take on it at least.

It's a chain reaction. The turbo works harder at high altitudes, it generates more power and thus also more heat. But the radiators that do most of the cooling are getting less air mass through them at high altitude.

[gruntguru]

There are two problems.
1. If the turbo is at or close to the 125k rpm limit at sea level, the MAP will be lower at altitude.

2. Even if rpm is OK, the turbo will need to operate at higher rpm, higher pressure ratio and higher inlet volume flow to achieve the same mass flow at altitude. This new operating point may be at a significantly lower efficiency than for sea level.