Turbo Cooldown?

[pauly221]

Hey all- I'm pretty new to turbos, and I was wondering about the recommended cool-down period before you shut off the engine. I forget what Mazda recommends--something around 30-60 seconds of idle. I have a couple questions about this.

First, how necessary is this cool-down? Should I still let the engine idle even if I haven't been accelerating hard or driving at high speeds? Would it be sufficient to just drive the last few minutes of my commute gently with soft acceleration and braking?

Second, is 60 seconds even long enough to let the turbo cool-down? Seems like it would take far longer than that to get it to a reasonably cool temperature. I know there is the risk of coking and such, would the intercooler take care of that problem?

Any thoughts? I'm loving the car so far, just want to make sure I keep it running as long as possible.

-Paul

[ryceboi]

our turbo is both oil and water cooled, so it is unnecessary to idle your car under normal driving. if you are under boost and pushing the car hard, then you should sit and wait anywhere from 1-5 minutes at your discretion of how hard you drove.

[Steiner]

It is very necessary after hard driving because the turbo is superheating the oil and once you turn off your car the oil stops moving and will boil or coke.

[MrTea]

one thing to keep in mind is, i don't know how all you guys drive, but i don't boost into a parking lot. once you are off boost, all it takes is a good 30-60 sec of off boost driving to cool things down where they won't be an issue. in most (90%) cases, it takes that long to get into a parking lot and find a spot, or turn into your housing track and pull into the drive. then only time i've ever had to worry even a bit about cooling it down was on the track when a red flag kept us from doing our cool down lap. and it only sat for 30sec before temps got down.

[pauly221]

If the turbo kicks in, do you always feel the boost? It's easy to feel when I accelerate hard and get pressed into the seat, but I'm not so sure about a more gentle start or while driving at a constant speed, whether it be 25mph or 75mph. Is it possible to get boost without noticing?

[Steiner]

The turbo is always spinning and a small amount of boost pressure might not be noticable

[MrTea]

i'm not sure what that was referring to? but even at idle the turbo is spinning, so it's not like you want it to stop spinning. unless you are pushing the car, oil temps should be dropping, which you can see with a gauge. though it's not the end all reading, but those with boost questions should check out a book called "maximum boost" it answers a lot of questions in regards to owning and tuning a turbo.

[ryceboi]

the answer is in the flow rate. if the flow rate of the turbo at a given time is greater than the flow rate that is entering the cylinders + the wastegate bleed off, then you are creating boost. but otherwise, as long as there is airflow through the turbo, then the wheel is spinning.

a turbo doesnt actually compress air even tho it is called a compressor. what it does is push air into a given volume and the more air molecules you fit into a given volume, the higher the pressure becomes.

[pauly221]

My reason for asking about noticing boost is because the concept of "driving hard" seems a little vague to me. My daily commute certainly doesn't compare with track driving, but depending on how late I oversleep, I can do a fair amount of hard accelerating. :) I try to take it easy as I get close to the office and I don't notice the boost then, but I just wasn't sure if that is enough to let the turbo cool down or if I still need to let the car idle before turning it off.

This forum is great! Thanks for all your help guys!

[Confuc1ous]

I have seen kits they have on other cars that have turbo's where the car itself will remain on even after the passengers have left the car and walked off. Is that some sort of timer associated with the cool down period of the turbo? I wonder if it would have any benefit installed into the MS6?

[MrTea]

yes, that's a "turbo timer" and is used to cool things down so hot oil isn't sitting in the superheated turbo housing. that is also what this thread is about, is it beneficial for the speed6. the answer is, if you want it, put it on, if not, there's no need.

[Progalex]

yes, that's a "turbo timer" and is used to cool things down so hot oil isn't sitting in the superheated turbo housing. that is also what this thread is about, is it beneficial for the speed6. the answer is, if you want it, put it on, if not, there's no need.

I agree.

I simply make sure my last 1-5 min drive time is without any hard accelerations. But I think that if you want to make sure you can alwalys stay an extra 60 seconds inside your car, admiring it, before shutting the engine off.

Also, I quickly opened my hood yesterday after turning the engine off and I could distinctivly hear some mechanical noises happening...? My friend told me it could probably be some sort of oil transfer being done to the turbo.....anybody has a clue of what I'm talking about?

Thanks!

[MrTea]

next time check the TB. the ETB cycles after shutoff, it makes a lot of noise.

[Progalex]

next time check the TB. the ETB cycles after shutoff, it makes a lot of noise.

Sorry I dont know what you mean by that: what does TB and ETB mean?

[MrTea]

TB= throttlebody
ETB=electonic throttlebody
when you turn the key on, the TB will cycle, same thing a few seconds after turning off