Whoopsy:The farmer:I do hope you don’t have a manual gearbox....
I keep checking for a 3rd pedal all morning
Maybe you got a "one off" version?
RC (Germany) - Rennteam Editor Lamborghini Huracan Performante (2019), Mercedes E63 S AMG Edition 1 (2018), Mercedes C63 S AMG Cab (2019), Range Rover Evoque Si4 Black Edition (2019)
Whoopsy:The rear springs off my GT2RS. They took a real beating for sure 3 days at the Ring and one full day at my track. Right now 2800km on the clock.
The one on the left, the separator has gone cleanly into the spring coating.
I had a talk with one of the mechanics at Manthey yesterday, they said they consume so much of their water tanks, after 6 laps even their 14 liter setup is finished. I never thought it consumed that much. He couldn't really say what the difference in power is when the water is depleted, but he said it is substantial. Do you notice the same?
1969 Mercedes-Benz 300SEL 6.3 / 2008 Porsche 911 GT3 RS (sold) / 2011 Mercedes-Benz C63 AMG Performance / 2014 BMW-Alpina D3 biturbo Touring / 2018 Porsche 911 GT3 Clubsport
Porker:
I had a talk with one of the mechanics at Manthey yesterday, they said they consume so much of their water tanks, after 6 laps even their 14 liter setup is finished. I never thought it consumed that much. He couldn't really say what the difference in power is when the water is depleted, but he said it is substantial. Do you notice the same?
It depends how hot the post turbo/intercooler intake temperature gets maximum power is usually there up to about 50DegC the program has tables which will gradually reduce the boost and the timing and increase the fuelling per each incremental intake temperature increase this will keep the exhaust gas temperatures within spec and will keep the intake temps from going too high.
Have a look at the tables below these are for my 997 Mezger motor which was running VTG turbos at the time you can see how at 50.25DegC IAT it starts to reduce boost from 2000rpm upwards so at 5000 rpm boost is at 0.979980 of its programmed optimum so if that should be 1.5bar it would now be 1.47bar
If the ambient is 30DegC and there is no water spray left the intakes could easily rise to 45DegC above ambient ie 75DegC so on these tables at 6000rpm onwards the engine would get 0.914917 of optimal boost which if was on a GT2RS its 1.5bar would be reduced to 1.37bar.
Timing and feulling will have similar tables with of course everything interacting. The engine could lose 150+hp if the temps can't be controlled that would still mean 550hp which is a lot of horsepower and heat to manage.
997 GT2 2014 3.9 Mezger, 800PS @ 1.2 bar
2018 McLaren 720S
993 Turbo, 2006 built 3.8, 577PS/797NM, 1440kg DIN sold to a worthy enthusiast.
Really interesting, thanks Toby.
Would the need for such water injection be negated if they fitted properly expensive intercoolers (genre Secan, etc...?)
1969 Mercedes-Benz 300SEL 6.3 / 2008 Porsche 911 GT3 RS (sold) / 2011 Mercedes-Benz C63 AMG Performance / 2014 BMW-Alpina D3 biturbo Touring / 2018 Porsche 911 GT3 Clubsport
Porker:Really interesting, thanks Toby.
Would the need for such water injection be negated if they fitted properly expensive intercoolers (genre Secan, etc...?)
As far as I heard, the GT2 RS was supposed to be put on the market with 650 hp only. Then came the 720S...
The GT2 RS engine is basically the 991.2 Turbo S engine, so you can imagine where the issues lie.
They had to make a track proof engine with 700 hp out of this.
The water injection was apparently the only way to achieve the power they needed without compromising performance, reliability and...trara...EU emissions.
RC (Germany) - Rennteam Editor Lamborghini Huracan Performante (2019), Mercedes E63 S AMG Edition 1 (2018), Mercedes C63 S AMG Cab (2019), Range Rover Evoque Si4 Black Edition (2019)
Porker:Really interesting, thanks Toby.
Would the need for such water injection be negated if they fitted properly expensive intercoolers (genre Secan, etc...?)
The Secan coolers would definitely help massively and in conjunction with the water sprayer, even better but it is difficult to control the heat from VTGs because of the combo of high boost and high turbine back pressure.
I have seen pics of the GT2RS intercoolers and they are not like the normal 991 items they have proper ali end tanks and will have a decent DIN core also the track version (with that same 991.2 engine) has much bigger units located in the back bumper but again they are not Secan quality but then there is no way Porsche are going to spend 8000 odd Euros on intercoolers unless of course they have races to win !
It is interesting that at the last vmax airfield event in 33DegC heat the 720Ss were only trapping at 202mph whereas in cooler temps they have been as fast as 212mph, they use water cooled intercoolers with a radiator at the front cooling the water which is then fed to the intercoolers at the back but at vmax one has to sit idling waiting for the run and the intake temps usually start at 25degC above ambient (from my 997 data) so 58DegC to start and they likely don't recover as the water system is not as efficient as a good air/air. We reckon (when compared to other cars on the day) the 720s were running about 630hp so they lost 110hp in those conditions.
997 GT2 2014 3.9 Mezger, 800PS @ 1.2 bar
2018 McLaren 720S
993 Turbo, 2006 built 3.8, 577PS/797NM, 1440kg DIN sold to a worthy enthusiast.
Jul 10, 2019 4:52:59 PM
Whoopsy:lukestern:GT3 RS wheels seems wrong on a GT2 RS
epic spec btw!
They share the exact same wheels, so in a way Porsche short changed the spec sheet lol.
It's pretty much loaded to the max without going PTS. (PTS green cars are for old people)
Don’t you be rude just cause you are a couple of years younger.....
TB993tt:I have seen pics of the GT2RS intercoolers and they are not like the normal 991 items they have proper ali end tanks and will have a decent DIN core also the track version (with that same 991.2 engine) has much bigger units located in the back bumper but again they are not Secan quality but then there is no way Porsche are going to spend 8000 odd Euros on intercoolers unless of course they have races to win !
Those Secan chillers are standard on the GTS
2017 991.2 Carrera 4 GTS | GT Silver Metallic - The GT3 Killah!
2013 Audi S3 | Glacier White
Jul 10, 2019 6:21:08 PM
RC:Porker:Really interesting, thanks Toby.
Would the need for such water injection be negated if they fitted properly expensive intercoolers (genre Secan, etc...?)
As far as I heard, the GT2 RS was supposed to be put on the market with 650 hp only. Then came the 720S...
The GT2 RS engine is basically the 991.2 Turbo S engine, so you can imagine where the issues lie.
They had to make a track proof engine with 700 hp out of this.
The water injection was apparently the only way to achieve the power they needed without compromising performance, reliability and...trara...EU emissions.
The water for the 2RS is spray on coolers to maintain acceptable temperature. It has nothing to do with emission. Let’s wait for a bit of a time before calling the engine bulletproof. For now, these cars are on sale or collecting dust in garage because the owner thinks that was rare
GT Lover, Porsche fan
991.2 GT3 manual, 991 GT3 2014(sold)
Cayenne GTS 2014
Porker:Whoopsy:The rear springs off my GT2RS. They took a real beating for sure 3 days at the Ring and one full day at my track. Right now 2800km on the clock.
The one on the left, the separator has gone cleanly into the spring coating.
I had a talk with one of the mechanics at Manthey yesterday, they said they consume so much of their water tanks, after 6 laps even their 14 liter setup is finished. I never thought it consumed that much. He couldn't really say what the difference in power is when the water is depleted, but he said it is substantial. Do you notice the same?
We never went dry that day in June on my track, we used up pretty much the whole Manthey tank worth of water in 29 degree ambient on a sunny day. 40 laps, split between me and 3 pro racers, just under 200km track miles.
I had my tank level sensor dead since delivery so it was constantly showing low water level. But when I finally got the car back to the shop and the foreman pulled the factory tank out, it was still almost full, so I know for sure we drained the whole 15 litres on track.
The Ring has more wide open throttle sections than my track so I guess it demands more water injection also.
Whoopsy:Gnil:Why did you dismount the springs ? Are you changing them ?
I got brand new springs from Porsche replaced under warranty. These are the worn down ones.
Under warranty because you tracked the car a few times and got 1.7 lateral G's ....... Maybe I should ask for new ones too
964 Carrera 4 -- 997.2 C2S , -20mm -- 991.2 GT3 RS
Jul 11, 2019 6:48:44 AM
the-missile:The water for the 2RS is spray on coolers to maintain acceptable temperature. It has nothing to do with emission. Let’s wait for a bit of a time before calling the engine bulletproof. For now, these cars are on sale or collecting dust in garage because the owner thinks that was rare
I was in Imola over the weekend for the Porsche Suisse Cup, 3 GT2 RS were on the track but I did not ask about water consumption. There are at least quite a few GT2 RS owners using the car on track which is a good sign. However, one had a crash with another car.
Josef:I was in Imola over the weekend for the Porsche Suisse Cup, 3 GT2 RS were on the track but I did not ask about water consumption. There are at least quite a few GT2 RS owners using the car on track which is a good sign. However, one had a crash with another car.
The problem with the GT2 RS on regular tracks is not the water , it' s the break pad wear
964 Carrera 4 -- 997.2 C2S , -20mm -- 991.2 GT3 RS
Jul 11, 2019 10:14:48 AM
the-missile:RC:Porker:Really interesting, thanks Toby.
Would the need for such water injection be negated if they fitted properly expensive intercoolers (genre Secan, etc...?)
As far as I heard, the GT2 RS was supposed to be put on the market with 650 hp only. Then came the 720S...
The GT2 RS engine is basically the 991.2 Turbo S engine, so you can imagine where the issues lie.
They had to make a track proof engine with 700 hp out of this.
The water injection was apparently the only way to achieve the power they needed without compromising performance, reliability and...trara...EU emissions.
The water for the 2RS is spray on coolers to maintain acceptable temperature. It has nothing to do with emission. Let’s wait for a bit of a time before calling the engine bulletproof. For now, these cars are on sale or collecting dust in garage because the owner thinks that was rare
Thermodynamics always have to do with emissions...
RC (Germany) - Rennteam Editor Lamborghini Huracan Performante (2019), Mercedes E63 S AMG Edition 1 (2018), Mercedes C63 S AMG Cab (2019), Range Rover Evoque Si4 Black Edition (2019)
Jul 11, 2019 11:30:45 AM
not when the CPU limit the HP because the cooling system is out of range. the car at 650hp will have less emission than the car at 700hp. Thermodynamics effect here limits the power available for the car and reduce or maintain the emission due to lower HP. except if a sensor is deficient.
Actually, it is when the engine is cold that the emission is the worst due to the compensation of the rich mix fuel/air to heat up the engine...
GT Lover, Porsche fan
991.2 GT3 manual, 991 GT3 2014(sold)
Cayenne GTS 2014
Jul 11, 2019 11:35:11 AM
the-missile:not when the CPU limit the HP because the cooling system is out of range. the car at 650hp will have less emission than the car at 700hp. Thermodynamics effect here limits the power available for the car and reduce or maintain the emission due to lower HP. except if a sensor is deficient.
Actually, it is when the engine is cold that the emission is the worst due to the compensation of the rich mix fuel/air to heat up the engine...
https://digital.lib.uidaho.edu/digital/collection/IR/id/11
A single cylinder, four stroke, gasoline, spark ignition engine was modified to test the effects of water injection in combination with an increased compression ratio in a engine. Three air/fuel ratios (13.7, 14.7 and 15.7), six water/fuel mass ratios (from 0 to .75) and two different compression ratios (6:1 and 7:1) were tested. It was found that water injection in combination with an increased compression ratio can increase torque output (up to 65%), reduce brake specific fuel consumption (up to 39%), lower exhaust temperature (up to 10%), lower BSNO emissions (by up to 78%) and lower BSCO emissions (by up to78%) but may increase BSHC emissions (up to 45%).
RC (Germany) - Rennteam Editor Lamborghini Huracan Performante (2019), Mercedes E63 S AMG Edition 1 (2018), Mercedes C63 S AMG Cab (2019), Range Rover Evoque Si4 Black Edition (2019)
RC:A single cylinder, four stroke, gasoline, spark ignition engine was modified to test the effects of water injection in combination with an increased compression ratio in a engine. Three air/fuel ratios (13.7, 14.7 and 15.7), six water/fuel mass ratios (from 0 to .75) and two different compression ratios (6:1 and 7:1) were tested. It was found that water injection in combination with an increased compression ratio can increase torque output (up to 65%), reduce brake specific fuel consumption (up to 39%), lower exhaust temperature (up to 10%), lower BSNO emissions (by up to 78%) and lower BSCO emissions (by up to78%) but may increase BSHC emissions (up to 45%).
That is in cylinder water injection completely different to water spraying over outside of intercooler cores a la GT2RS which is there solely to reduce IAT
--
997 GT2 2014 3.9 Mezger, 800PS @ 1.2 bar
2018 McLaren 720S
993 Turbo, 2006 built 3.8, 577PS/797NM, 1440kg DIN sold to a worthy enthusiast.
TB993tt:RC:A single cylinder, four stroke, gasoline, spark ignition engine was modified to test the effects of water injection in combination with an increased compression ratio in a engine. Three air/fuel ratios (13.7, 14.7 and 15.7), six water/fuel mass ratios (from 0 to .75) and two different compression ratios (6:1 and 7:1) were tested. It was found that water injection in combination with an increased compression ratio can increase torque output (up to 65%), reduce brake specific fuel consumption (up to 39%), lower exhaust temperature (up to 10%), lower BSNO emissions (by up to 78%) and lower BSCO emissions (by up to78%) but may increase BSHC emissions (up to 45%).
That is in cylinder water injection completely different to water spraying over outside of intercooler cores a la GT2RS which is there solely to reduce IAT
--
997 GT2 2014 3.9 Mezger, 800PS @ 1.2 bar
2018 McLaren 720S
993 Turbo, 2006 built 3.8, 577PS/797NM, 1440kg DIN sold to a worthy enthusiast.
I was referring to thermodynamics/cooling, there is (unfortunately) no scientific work regarding water spraying, at least not one I am aware of.
Water spraying prevents or suppresses detonation, very similar to water injection but with a different approach (intercoolers).
Everything involving thermodynamics/cooling also involves emissions in a way or another.
Air temperatures (intake) are very important to the power output but also affect emissions. Power increases -> emissions increase (indirectly).
The secret is to find a perfect balance of power increase, emissions and reliability. And of course how much water is needed. Now if someone could invent some sort of dry ice cooling system...
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RC (Germany) - Rennteam Editor Lamborghini Huracan Performante (2019), Mercedes E63 S AMG Edition 1 (2018), Mercedes C63 S AMG Cab (2019), Range Rover Evoque Si4 Black Edition (2019)
Jul 11, 2019 12:38:08 PM
RC:the-missile:not when the CPU limit the HP because the cooling system is out of range. the car at 650hp will have less emission than the car at 700hp. Thermodynamics effect here limits the power available for the car and reduce or maintain the emission due to lower HP. except if a sensor is deficient.
Actually, it is when the engine is cold that the emission is the worst due to the compensation of the rich mix fuel/air to heat up the engine...
https://digital.lib.uidaho.edu/digital/collection/IR/id/11
A single cylinder, four stroke, gasoline, spark ignition engine was modified to test the effects of water injection in combination with an increased compression ratio in a engine. Three air/fuel ratios (13.7, 14.7 and 15.7), six water/fuel mass ratios (from 0 to .75) and two different compression ratios (6:1 and 7:1) were tested. It was found that water injection in combination with an increased compression ratio can increase torque output (up to 65%), reduce brake specific fuel consumption (up to 39%), lower exhaust temperature (up to 10%), lower BSNO emissions (by up to 78%) and lower BSCO emissions (by up to78%) but may increase BSHC emissions (up to 45%).
Christian, you are mixing water sprayed to the coolers as the GT2RS and injection of water into the cylinders as done by BWM...completely different stuff with completely different results...
Porsche Technology used for the GT2RS is not related to emission, only related to maintain engine temperature at acceptable value in order to maintain safe 700hp otherwise the system downgrades itself.
what you quoted is High Tech mix of Air/Fuel/Water-Vapor which change the mix and the efficiency of the engine. zero criteria in common with the 2RS.
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GT Lover, Porsche fan
991.2 GT3 manual, 991 GT3 2014(sold)
Cayenne GTS 2014