Turbo in my 2.0 Jaguar

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I've seen a lot of mid-sized late model (latest models) cars and SUVs like BMW, MB, Volvo, Lexus, Alfa Romeo etc have 2.0 Turbo engines. After all these years I am still confused about Turbos. I noticed in my Jaguar, if I floored the gas pedal, there is a 2 second delay and of she goes like a cat running for it's life. Is the Turbo still in full operational even the car already reaches the highest speed? Are Turbos just a speed booster? Please enlighten me. Thanks fellow members
 
I've seen a lot of mid-sized late model (latest models) cars and SUVs like BMW, MB, Volvo, Lexus, Alfa Romeo etc have 2.0 Turbo engines. After all these years I am still confused about Turbos. I noticed in my Jaguar, if I floored the gas pedal, there is a 2 second delay and of she goes like a cat running for it's life. Is the Turbo still in full operational even the car already reaches the highest speed? Are Turbos just a speed booster? Please enlighten me. Thanks fellow members
It is called turbo lag. Primary performance benefit of turbo is more torque at lower rpms in wider rpm band from smaller displacement.
 
Is the Turbo still in full operational even the car already reaches the highest speed? Are Turbos just a speed booster?
Depends on the application.
Most of the time they are always running some level of boost, so they are spinning. Just depends how much throttle you are giving it.
This is why turbo vehicles need to adhere to a much stricter maintenance schedule. The amount of heat and pressure it creates on the engine is substantially more than on a naturally aspirated motor.
 
That's just turbo lag. But yeah they force air in which allows for more fuel to be injected in and for more to be accomplished in the chamber. There's a reason to use electric turbos, twin scroll, or variable twin scroll or variable geometry turbos instead of the simple single scroll. But as you guessed the simpler the more reliable. Mitsubishis single scroll turbos are known to be some of the most reliable. It's why Honda uses them on their new turbo engines and they're very reliable.
 
I'm no turbo expert, but it is my understanding that a turbocharger is always giving some boost, but it is much more pronounced with higher engine RPM. Higher engine RPM means more exhaust, which drives a turbo. As long as the engine is working hard, the turbo is going to be boosting.

You mention a 2 second delay in boost. That seems unusually long. I thought turbo boost delays are typically <1second, with many being half of that.
 
Another way to think about turbochargers, especially the lag is that they are powered by the exhaust gasses (except the electric ones). Therefore the more throttle you apply, the faster the turbo spins, and the more intake pressure it creates.
There is a little bit of a "catch-up time" from when you hit the gas and the pressure builds in the exhaust, to spin the "compressor".(turbo)
Or, as the Germans call it Kompressor.
 
Thank you guys from OP. While watching a YT video "Do's & Don'ts on Turbo" I read a comment from one who watched the video to floor the gas pedal from time to time in order to lube the Turbo. Is this true? It sounds a little crazy.
 
I've seen a lot of mid-sized late model (latest models) cars and SUVs like BMW, MB, Volvo, Lexus, Alfa Romeo etc have 2.0 Turbo engines. After all these years I am still confused about Turbos. I noticed in my Jaguar, if I floored the gas pedal, there is a 2 second delay and of she goes like a cat running for it's life. Is the Turbo still in full operational even the car already reaches the highest speed? Are Turbos just a speed booster? Please enlighten me. Thanks fellow members
Depends in your speed. At idle the turbos are spinning comparatively slower than when you're moving at say 1500 rpms so there's more delay at idle. Automakers have done a great job at reducing the delay by using smaller turbos.

Turbos provide a lot of torque and an extremely flat torque curve. People drive torque. This gives you that push in the seat up until you reached the maximum allowed by the DME. Wastegates are typically used to regulate the amount of boost delivered by the turbo. Variable vane turbos can be used instead of fixed turbo w/wastegate as it can modulate the speed of the air (I can't remember if the variable vanes are on the exhaust or intake side or both.).

Torque curve of a NA engine (BMW S65). Notice how it slowly develops max torque in the beginning of the rpm range.

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Torque curve of TGDI (B58). Notice how quickly the engine develops max torque (1000 to 1500 rpms).

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Thank you guys from OP. While watching a YT video "Do's & Don'ts on Turbo" I read a comment from one who watched the video to floor the gas pedal from time to time in order to lube the Turbo. Is this true? It sounds a little crazy.
Can't lube any more than what's already being lubed.
 
I noticed in my Jaguar, if I floored the gas pedal, there is a 2 second delay and of she goes like a cat running for it's life. Is the Turbo still in full operational even the car already reaches the highest speed? Are Turbos just a speed booster? Please enlighten me. Thanks fellow members

It's not always in boost; there is vacuum until the turbo spins fast enough to make boost. Most turbos nowadays are properly sized for their application. You might notice just a slight bit of turbo lag but that's also dependent on the RPM you are at when you floor it. Are you sure it's not the transmission shifting as well?

Thank you guys from OP. While watching a YT video "Do's & Don'ts on Turbo" I read a comment from one who watched the video to floor the gas pedal from time to time in order to lube the Turbo. Is this true? It sounds a little crazy.

Nope, the oil pressure is always flowing and dependent on the overall oil pressure of your engine.
 
as always there are VARIABLES!! if you search + learn about turbocharging you can get all the answers. one thing for sure the ECU tuning controls modern turbo charged performance + OE tuning is meant for longevity so manufacturers need not WARRANTY $$$$ more than necessary!! i was amazed at my 2001 jetta 1,8T factory 150 hp + 162 TQ could be easily increased safely almost DOUBLE + DI turbos are even MORE "boostable" due to DI controlling engine knock!! due to the scope of info i will let YOU search + learn!
 
Are you sure it's not the transmission shifting as well?
It's auto shifting OK. It has ZF auto trans plus a Paddle shifter which I am afraid to use because I might messed up the auto trans. I just put it in D and go.
 
I'm no turbo expert, but it is my understanding that a turbocharger is always giving some boost, but it is much more pronounced with higher engine RPM. Higher engine RPM means more exhaust, which drives a turbo. As long as the engine is working hard, the turbo is going to be boosting.

You mention a 2 second delay in boost. That seems unusually long. I thought turbo boost delays are typically

very likely the trans is also downshifting
 
I would think this isn't turbo lag. It has far more to do with the 5 gears that it needs to drop from 8th to 3rd (or second) gear when you "mash the pedal". Any modern electronically controlled transmission with 5 or more gears has this lag as it tries to grab the lowest possible gear for the request you are giving it (100% throttle). Electronic throttle bodies won't just jump to full open until the transmission is in the proper gear for that.
 
I would think this isn't turbo lag. It has far more to do with the 5 gears that it needs to drop from 8th to 3rd (or second) gear when you "mash the pedal". Any modern electronically controlled transmission with 5 or more gears has this lag as it tries to grab the lowest possible gear for the request you are giving it (100% throttle). Electronic throttle bodies won't just jump to full open until the transmission is in the proper gear for that.

Mash the pedal? Where did you grow up? I haven't heard that expression since I moved away from rural South Carolina. It made me smile.
 
read that somewhere in old car and driver or other driving mags. Was a common term in the 80s and 90s.
 
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