After some sprited driving/driving hard you are suposed to leave the engine running for a few minutes to settle/cool before you turn the engine off either via the key or turbo timer (if equipted). Now I know this from being a member on here

So how will a person that owns either a UK Turbo, WRX or STi from a dealer. They won't tell him to do such a thing. So what damage can be done in not doing so - turning engine off striaght away after 'sprited driving'?

 

The turbo might fry

 

I think i read some of the oil stays around the turbo too long and goes sludgy

 

split pipes as they cool can be a problem

 

It says in the manual to let it idle for a minute before switching off.

As you switch of the engine the oil pump stops so the same 'bit' of oil stays in the turbo bearing so gets heated up excessively. At best this means the oil overheats and doesn't lubricate the bearing properly for those few moments while the turbo still spins; at worst the oil cokes (burns) forming carbon deposits that cause wear and can block the oil ways. If you idle the engine for a while the turbo cools and slows down to its idle speed and temperature, so the effect is reduced.

 

And from the sticker on the driver's door that tells you to do this?




Dealers won't tell you to warm a car up before extending it usually too. The number of people I've heard of that have been allowed to take a test drive and floor it within a few minutes of setting off is daft

If you don't let the car cool down after hard driving, the oil can't dissipate tremendous heat that has built up within the turbo, it just fries. IIRC this process leaves deposits/sludge that buggers your turbo sooner rather than later!

Ns04

 

Much less relevant with water cooled turbos as the water thermo-syphons and cools the turbo after switch off.

Simon

 

Thanks for the info guys. Much appriciated

 

It is better to drive normally for a few miles afterwards if thats practical. Allows the whole car to cool down, brakes, engine, turbo while being fully lubricated and water cooled.

No hot spots or heat soak.

Brake calipers get hot so the part of the disk inside the caliper cools down much slower than the rest of the disk on a parked car and can lead to warping.

If not, run the engine for a bit (3 mins ?)

 

People who care about the mechanical side of their car would know this already, by researching before purchasing a vehicle.....

At the end of the day, its 'sales people' selling these cars, not mechanical engineers.

 

Ive managed to get my turbo timer to count down for 4 and a half minutes when ive taken the key out. You can get in the house have a cup of tea and make a sandwich by the time the thing switches off!

 

If you just drive around at normal local traffic speeds at low revs before you reach your destination, you will never need to let the engine idle.

The "warm up" advice on here is a bit ott too. Unless you insist of using sludge for engine oil like 15w40, 15w-50, 20w50 or 10w60. As they are all rather thick when cold/cool for the UK climate, especially in winter.

 

yer mate i got a wrx wagon with no turbo timer and i always leave it to cool down for at least a minuite depending on how hard ive drove it.

 

To be honest, i think its good practice to just let the engine idle for 30secs or soo regardless of how hard you drive it. At the end of the day being OTT is better than not caring at all... and im willing to sacrifice 30secs of my life even after a gentle drive (usually taken up by me sorting myself out before i get out anyways... last thing i always do is turn the car off as im outside the car and just about to lock.

If you have really kicked its ring, then i leave mine for about 2-4mins to idle... i want a Turbo Timer, but have been told i need a new alarm first? like a clifford... am i correct in thinking this? (MY05 STi)

 

I think you only need new alarm if you want to walk away with it still running,which is going to save you a short time only. Turbo timers just allow the job to be done automatically. imho anyway

 

Anything approaching 4 mins is overkill IMHO. Mines left no more than around 20 seconds , not at all if I haven't been driving hard.

 

I would leave mine for between one and two minutes after every journey, hard or not.......

 

 

i know someone who had an MR2 turbo with a turbo timer, but rearly used the turbo timer, even after hard runs Result - turbo fried & died!

 

i have a timer built into the alarm on mine, i use it now and again, but the bit on here about driving steady for a mile or 2 before you know you need to stop is the rule i usually go down......

 

I did this with my old Sccob, do it now with my 330d & will do it again when the new Scoob is on the drive

TX.

 

By running the car 'down' (gentle driving before stopping) i find this a far better practice than leaving a car idling which is an excesses use of fuel,noise annoyance etc.

 

I live on a slight hill and whenever possible just knock my car out of gear and coast at 30mph for a good 3/4 of a mile , therefor low revs and cool air passes through and not had a problem yet

Although its not always poss to do that so after a hard drive i tend to leave it running for a minate or so

Dave

 

That's what I generally do. Coming back from night shift at 6am, the last thing neighbours want to hear is a loud car idling for minutes on end. Being on a slight hill, I knock the car into neutral down to my house and switch off right away. Waste of time and money letting the car idle for minutes on end.

 

too true mate if you can coast then its deff the best , least annoying (for the neighbour ) and easiest way to do it if you can

Dave

 

Doesn't waste time as you just turn off as the last thing you do. So, look in mirror do hair, look in glovebox for lost somethingorother, pick up paperwork off front seat, get suit jacket from back seat & put it on, release kids from back & remove child seat, empty shopping from boot etc etc. Get the picture?

TX.

 

Yes, generally put the disclock on, 10 seconds max, then switch off

 

Turbo Timers are a complete waste of money. Money is better wasted on a gaugeof some description on the simple basis that you have sommat pretty to look at for your money

 

Of course idling while coasting also means the oil pressure drops and reduces the flow around the hot engine, better to leave it in gear and keep the revs ~3k on light/no throttle.

Remember, the engines are not chocolate, but sensible cooldown after a thrash is worth while.

 

Got mine up to 5 minutes 5 seconds on the way back from japfest today, max it counts to is 10 minutes