how many turbos?
09-01-2006, 11:24 AM
#16
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Originally Posted by NOTORIOUS VR
no.. it has nothing to do with what an engine can handle...
It has to do with head design/flow, the number of firing cycles, displacement, efficency of the turbo(s), manifold design/flow, space restrictions, etc, etc, etc, etc... the list goes on...
no.. it has nothing to do with what an engine can handle...
It has to do with head design/flow, the number of firing cycles, displacement, efficency of the turbo(s), manifold design/flow, space restrictions, etc, etc, etc, etc... the list goes on...
Originally Posted by wacKo
so that cant be referred to the turbo handling limit of a single engine? if not can someone explain that a little more?
appreciated:thumbsup:
appreciated:thumbsup:
ill give a thousand points to whoever answers best?
09-01-2006, 03:51 PM
#17
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the "turbo handling" of an engine usually refers to how much boost an engine can take, what NOTORIOUS VR is talking about is what the engine can do with the boost, if you valves are too small then all that "boost" or air can't even enter the cylinders, so it just gets stuck in the intake. The problem is not how much air we can cram into a engine, it's what that engine can do with it, and when it "explodes". If you are trying to make a 1500hp car, who cares about turbo lag, you are not racing at 1500rpm anyway, you will always be in the high reves, so it doesn’t matter. In contrast if you want something that is street able with no (or little) turbo lag, then you don't need to be running 30psi on the street, so you don't need 4 turbos. Why not more then two? because two is enough to have very little lag, yet enough boost to reach the limits of your engine, want more power? just get a better turbo (or two) there is a Talon running like 35 psi on a 4-cylinder engine with 8 injectors, why do you need 35psi X 3 or 4.. you don't. In my option turbo's are just to perfect it's like perpetual power.
can I have 1000 pts? lol
Steve.
can I have 1000 pts? lol
Steve.
09-01-2006, 07:18 PM
#18
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Originally Posted by hacker_720
why do you need 35psi X 3 or 4.. you don't. In my option turbo's are just to perfect it's like perpetual power.
can I have 1000 pts? lol
Steve.
can I have 1000 pts? lol
Steve.
The only time your PR (pressure ratio) is multiplied is when u'r running a compound turbo setup (which is pretty much impossible for a gasoline engine to do). This is what diesel engines run in high performance applications, which run around 130 psi of boost.
Regardless... The # of turbos has less to do with the engine itself then it does with the entire packaging. A 4cyl engine can be made to withstand 1000HP, but in reality to get tho's numbers you'd want to use a single turbo as it's a lot more efficent then a twin setup, not to mention cheaper in the fabrication process and easier to package under the hood.
09-04-2006, 11:28 PM
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Originally Posted by pg29
it is possible to twin charge a gasoline engine. in an SCC article, they showed a mini that had the stock supercharger blowing air into a small turbo, then into the engine, so it is possible.
Twincharging is totally different.
Also the only reason diesels get away with a compound setup is because they don't detonate...
09-05-2006, 11:52 AM
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sorry, notorious vr , you right the tubos don't add to each other, I was just trying to make it simple, but you knew that. And yes those turbo desiels is where it's going, can't wait for that to hit mainstream tuning, makes Gas engeins look like they are made of cardboard.
09-09-2006, 02:06 PM
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Courtesy of Wikipedia:
Parallel Twin-Turbo
Parallel Twin-Turbo refers to a turbocharger configuration in which two identical turbochargers equally split the turbocharging duties. Each turbocharger is driven by one half of the engine's spent exhaust energy. In most applications, the compressed air from both turbos is combined in a common intake manifold, and sent to the individual cylinders. Both turbos function simultaneously, unlike sequential twin-turbos. Commonly each turbocharger is mounted to its own individual exhaust/turbo manifold, however on inline-type engines both turbochargers could be mounted to a single turbo manifold. Parallel twin turbos are usually applied to V-shaped engines where one turbo is assigned to each cylinder bank, providing packaging symmetry, and simplifying plumbing; however, it is not unknown for a parallel set-up to be used on an inline engine. Nissan's RB26DETT is an inline-6 that uses a twin-turbo set-up, the twin-turbo inline-6 in the BMW 335i (E90) coupe also utilizes a parallel twin-turbo set-up.
While a parallel twin-turbo set-up theoretically has less turbo lag than a single turbocharger set up, because of marginally-reduced combined inertial resistance, and often simplified exhaust plumbing, the fact that both turbos spool at more or less the same time means that there is still a noticeable bit of lag, especially in high-flow turbo/high boost applications. One way to counter this is to use a light pressure set up where the turbos are designed to output less boost but spool earlier, however, this set up sacrifices top end power. Another system would be the use of variable geometry turbochargers, this system changes the angle of the guide vanes depending on the exhaust pressure giving the system excellent power throughout the rev range. Once used mainly in turbocharged diesel engines, Porsche was the first to use it in a mass-production gasoline-powered vehicle in 2006 with the 911 Carrera Turbo (997).
Sequential Twin-Turbo
Sequential Twin-Turbo refers to a set up in which the motor can utilize only one turbocharger for lower engine speeds, and both turbochargers at higher engine speeds. During low to mid engine speeds, when available spent exhaust energy is minimal, only one turbocharger (the primary turbocharger) is active. During this period, all of the engine's exhaust energy is directed to the primary turbocharger only, lowering the boost threshold, and increasing power output at low engine speeds. Towards the end of this cycle, the secondary turbocharger is partially activated (both compressor and turbine flow) in order to pre-spool the secondary turbocharger prior to its full utilization. Once a preset engine speed or boost pressure is attained, valves controlling compressor and turbine flow through the secondary turbocharger are opened completely. At this point the engine is functioning in a full twin-turbocharger form, providing maximum power output. Sequential twin-turbocharger systems provide a way to decrease turbo lag without compromising ultimate boost output and engine power. Examples of cars with a sequential twin-turbo setup include the 1993-2002 Toyota Supra Turbo (JZA8x), the 1992-2002 Mazda RX-7 Turbo (FD3S), and the 1986-1988 Porsche 959. With recent advancements in turbocharger design, sequential twin turbo systems have fallen out of favor because they are seen as unnecessarily costly and complex.
Compound turbocharging
Compound turbocharging is a technique used to achieve extremely high pressure ratios. It is common in racing with diesel engines (For example Tractor pulling) due to their combustion properties that take well to high boost pressures and are not limited by fuel stability like spark ignition engines. Boost pressures of around 7 bar gauge pressure (101 psi) are common and as high as 10 bar (145psi) in some cases. A normal turbocharger has a maximum pressure ratio of around 3 but there are turbochargers in existence specially designed for high boost which have maximum pressure ratios of typically 4-5. In this configuration one turbocharger is used to pressurize the air coming into the inlet of the other, resulting in a multiplication of the pressure ratios. Same goes for exhaust plumbing. For example if both turbochargers are running at pressure ratios of 3.0 and the atmospheric pressure is 1 bar the resulting pressures will be 3 bar absolute pressure at the inlet of the second turbocharger and 9 bar absolute pressure (8 bar gauge) at the inlet manifold of the engine. The pressure ratio in this example becomes 9.
Parallel Twin-Turbo
Parallel Twin-Turbo refers to a turbocharger configuration in which two identical turbochargers equally split the turbocharging duties. Each turbocharger is driven by one half of the engine's spent exhaust energy. In most applications, the compressed air from both turbos is combined in a common intake manifold, and sent to the individual cylinders. Both turbos function simultaneously, unlike sequential twin-turbos. Commonly each turbocharger is mounted to its own individual exhaust/turbo manifold, however on inline-type engines both turbochargers could be mounted to a single turbo manifold. Parallel twin turbos are usually applied to V-shaped engines where one turbo is assigned to each cylinder bank, providing packaging symmetry, and simplifying plumbing; however, it is not unknown for a parallel set-up to be used on an inline engine. Nissan's RB26DETT is an inline-6 that uses a twin-turbo set-up, the twin-turbo inline-6 in the BMW 335i (E90) coupe also utilizes a parallel twin-turbo set-up.
While a parallel twin-turbo set-up theoretically has less turbo lag than a single turbocharger set up, because of marginally-reduced combined inertial resistance, and often simplified exhaust plumbing, the fact that both turbos spool at more or less the same time means that there is still a noticeable bit of lag, especially in high-flow turbo/high boost applications. One way to counter this is to use a light pressure set up where the turbos are designed to output less boost but spool earlier, however, this set up sacrifices top end power. Another system would be the use of variable geometry turbochargers, this system changes the angle of the guide vanes depending on the exhaust pressure giving the system excellent power throughout the rev range. Once used mainly in turbocharged diesel engines, Porsche was the first to use it in a mass-production gasoline-powered vehicle in 2006 with the 911 Carrera Turbo (997).
Sequential Twin-Turbo
Sequential Twin-Turbo refers to a set up in which the motor can utilize only one turbocharger for lower engine speeds, and both turbochargers at higher engine speeds. During low to mid engine speeds, when available spent exhaust energy is minimal, only one turbocharger (the primary turbocharger) is active. During this period, all of the engine's exhaust energy is directed to the primary turbocharger only, lowering the boost threshold, and increasing power output at low engine speeds. Towards the end of this cycle, the secondary turbocharger is partially activated (both compressor and turbine flow) in order to pre-spool the secondary turbocharger prior to its full utilization. Once a preset engine speed or boost pressure is attained, valves controlling compressor and turbine flow through the secondary turbocharger are opened completely. At this point the engine is functioning in a full twin-turbocharger form, providing maximum power output. Sequential twin-turbocharger systems provide a way to decrease turbo lag without compromising ultimate boost output and engine power. Examples of cars with a sequential twin-turbo setup include the 1993-2002 Toyota Supra Turbo (JZA8x), the 1992-2002 Mazda RX-7 Turbo (FD3S), and the 1986-1988 Porsche 959. With recent advancements in turbocharger design, sequential twin turbo systems have fallen out of favor because they are seen as unnecessarily costly and complex.
Compound turbocharging
Compound turbocharging is a technique used to achieve extremely high pressure ratios. It is common in racing with diesel engines (For example Tractor pulling) due to their combustion properties that take well to high boost pressures and are not limited by fuel stability like spark ignition engines. Boost pressures of around 7 bar gauge pressure (101 psi) are common and as high as 10 bar (145psi) in some cases. A normal turbocharger has a maximum pressure ratio of around 3 but there are turbochargers in existence specially designed for high boost which have maximum pressure ratios of typically 4-5. In this configuration one turbocharger is used to pressurize the air coming into the inlet of the other, resulting in a multiplication of the pressure ratios. Same goes for exhaust plumbing. For example if both turbochargers are running at pressure ratios of 3.0 and the atmospheric pressure is 1 bar the resulting pressures will be 3 bar absolute pressure at the inlet of the second turbocharger and 9 bar absolute pressure (8 bar gauge) at the inlet manifold of the engine. The pressure ratio in this example becomes 9.
09-13-2006, 01:26 PM
#25
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in the end its all about how much you want to spend.
I've seen people with stock sequential, parallel setup and single from small to bigger than you head. All have different powerband which affects driveability.
In the end it's all about what you want out of the car
I've seen people with stock sequential, parallel setup and single from small to bigger than you head. All have different powerband which affects driveability.
In the end it's all about what you want out of the car
09-21-2006, 10:52 PM
#26
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To simplify, a twin turbo is two same sized turbos that spool up the same time for one engine and a sequential turbo is one small turbo that spools up a big turbo. Most people just put one turbo in or convert a car such as a supra from twin turbo to single. Although some people built custom turbo setups using more then twin turbos such as this
Kinda off topic but I wanted to show how many turbos can be used.
Kinda off topic but I wanted to show how many turbos can be used.
09-22-2006, 10:04 AM
#27
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yeh see so thats 2wice as much as a veyron, but the veyron has a 16 litre engine for it to use 4, so this car is either not using most of them, or has all of them turned to next-to-nothing boost?
and yes thats a question..
and yes thats a question..
09-22-2006, 09:42 PM
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There isn't much benefit of having 8 turbos, from what I heard, the car only made 700hp which is a lot in general but not for 8 turbos, really this is more of "it can be done" senerio just to prove it's possible.
