I have never had a vehicle with a Turbo engine. I began reading up one them to be ahead of the curve when I purchase the NX.

It seems as though it is recommended to let the car idle for 20-30 seconds before turning it off, in order to let the Turbo Engine cool down. Does anyone know if this is also true for the NX? Seems kind of odd to have to sit there and let it idle before getting out every time.

Sorry if any of my wording is wrong, I have never heard of this before today.

-Dennis

 

i dont think the NX needs to have a "cool down" period

unless your car is heavily tuned and you were pushing it really hard, those are the only instances where i see the need to let your car idle. as a factory tuned, daily driving, NON racing car, just drive it like any normal car

you can install a turbo timer into your car where after you turn off your ignition and leave, your car keeps running for like 30 seconds and turns off itself

 

On my wife's Mini Cooper S (which has a Turbo), there's a built-in timer system that keeps the fan and water pump system running to cool down the Turbo after the car ignition is off.

I don't know if there's such a system pre-installed on the NX, though I'm guessing the NX's Turbo system won't be running as hot... so there might not be a need for one.

 

This article goes in depth on the NX Turbo Engine. I dont see anything at all about a wait period after driving, but do see a lot about inter-coolers and cooling functions etc.

http://www.torquenews.com/1083/2015-...portant-decade

 

I've been driving a 3.0L Turbo engine in my Volvo for almost 5yrs and from what I have learned you don't have to let it idle/cool down. This is the case for oil-cooled turbo engines but my Volvo engine is water-intercooled which is the same for the NX...most modern turbo engines now use water-intercooler. I no longer idle my car and so far no issues have occurred with my engine nor anything has changed with regard to engine noise. You do however hear the turbo spooling or winding down forma few secs after engine shut off which is quite normal.

 

For oil cooled turbos, they deffinately need to be cooled down (duration depending on how hard the turbo was pushed). For those types of turbos, if you do not let the turbo cool before shutting down the car, the oil can coke (yes I meant to type coke) onto the surface, causing cracking and premature turbo shaft failure. So to avoid turbo coking, you need to let the oil cool down and drip out of the turbo housing.

For water cooled turbos, as what has been said above, you do not need to cool them down since there is no risk of oil coking.

For those that have never had a turbo motor, this is a good and must read and is everything you should know about turbo applications. https://www.turbobygarrett.com/turbobygarrett/faq

 

general rule of thumb - aftermarket turbos need the cooldown, while factory ones do not, as they have this in their ecu, and fans will keep working if needed even after you exit the car.

 

I was reading through the owner's manual and found this info on p168. It recommends idle cool down as follows

Normal city driving: ~20 seconds
High speed driving (constant speed above 50mph (80km/h): ~1 minute
High speed driving (constant speed above 62mph (100km/h): ~2 minute
Steep hill driving or continuous driving above 62mph (100km/h): ~3 minute

 

Wow! When I was doing my research....all the test write-ups, threads, & videos never mentioned the cool down....this is a BIG negative!
Thanks Wagnerian!

 

Why is it a big negative? Is 3 mins that important to your life?

 

It just seems odd to have to sit in your car for three minutes so the car can cool down, especially with the technology in the car. I got the NX F Sport a week ago and have not sat and waited for cool down.

 

Wow....my life must be so boring compared to you people who can't spend 3 minutes to wait. You do realize it will take you 1 minute to reach back behind your seat to pull your bag out (if you take one to work), and then another minute to shut everything off and put your sunshade into the window for the day. Or idk...listen to 1 song on the radio and then turn the car off.

Also, what do you mean, "especially with the tech in cars now"? How does your tech have anything to do with the MECHANICAL need to cool a component down?

People's need to rush anymore....yikes

 

The cool down instructions could just be a precaution on the part of Toyota/Lexus engineers. A majority of drivers probably don't look too closely at the owners manual and would never see the instructions. Unless it's covered at delivery, most will not be aware of it.

It certainly can't hurt though, IMO

 

^^^I believe that to be the case. In fact, on my delivery, my sales rep and others at the dealer not once mentioned a cool down process for the NX which leads me to believe it's not as critical as it sounds.

The driving I've been doing so far with the NX has been light such that the boost is low, typically in the negative to +2000 psi (max is 15,000). As such, I wait a few seconds in these conditions before shutdown.

After the break-in period, I'll have a little more fun hitting higher boost levels, but even at that, what I will do is drive the car easily (as I am now) the last few minutes prior to shutdown to minimize my idle time to a few seconds and not minutes.

However I'd love to hear from a Lexus Master Tech. TSopranoMB any feedback?

 

The entire discussion involves the bearings in the Turbo. When the engine shuts down the oil pump stops and there is no oil pressure. Engine bearings don't care because they are stopped but the turbo is still winding down. Remember that while an engine runs between 1000 - 6000+ RPM the turbo is going 10x that fast at times. No oil pressure + 40,000 RPM is obviously trouble. Synthetic Oil helps but letting the engine idle for a minute to bring the turbo down to a lower speed is key to a happy blower. (insert punchline here!)