n2trbl

Okay I searched and searched but I can't quite find my answer (again) I was looking for a good rule of thumb on cool down periods. I know this question is really worn out but one guy says 30 seconds to 1 1/2 mins is enough under normal driving conditions and another said he lets his idle for 9mins! Also I've heard you can easily cool you turbos buy driving under no-boost conditions. How is this done? What speed (generally) does boost kick in. And what speed (generally) does the second turbo kick in. I'm new to turbo cars (you have to start somewhere) and don't want to make the mistakes I hear all too often (that go along with 3rd gen specific 7's). Any help and suggestions would be greatly appreciated. Thank you for your time.

FormerPorscheGuy

Do a search under turbo timers.

FormerPorscheGuy

Here, I did one for you.

https://www.rx7club.com/forum/search...der=descending

n2trbl

I did search under the keywords "turbo timer" that's where I got all the conflicting answers. Thanks though I'm still looking through all the threads.

Mahjik

iTrader: (1)

There is no "cut and dry" answer, that's why you haven't found it in your searching. You'll have to look at all the threads and make up your own mind what you think needs to be done for your car.

turbojeff

iTrader: (30)

I'll give you a cut and dry answer.

Don't run the car under boost for the last part of the drive. That means just cruise for the last mile or so, this is the best cool down you can give the car.

If you were racing or tracking the car then you will need to let it idle for longer, preferrably with the fans on. A FD sitting idling for the most part will warm up without the fans. I can't see letting it idle for more than 5 min in any case.

The guy that lets his car idle for 9min doesn't really have an idea what is going on with the car. People come up with all sorts of weird rituals that technically don't make any sense.

Jeff
That's my take on it.

n2trbl

mahjik I know what you're saying. I was hoping one of the more educated people on this site would lend their opinions . I wasn't expecting to get a solid answer I was just hoping for some ballpark figure. 9 mins is over kill. I new to turbo cars and even I know that is way too long for any type of car. I thank you guys for your imput.

paw140

Letting your car idle for more and 30 seconds to a minute is stupid and a waste of gas, in my opinion, unless you ran your car REALLY hard before you stopped. For normal driving, just don't drive it hard for the last few minutes and shut down the engine when you park. I have never seen any proof that turbo timers help at all, and you probably won't find any; I think they are just a 'cool' gadget that people like to install.

I have owned 3 turbo cars, all of which did not have a turbo timer. My FD is at 91K miles, and my other two cars were at about 118K and 130K on the original turbos, and never had any problems.

BoostCrzy

you want the oil in the turbo to be flowing thru after running hard.....this will keep it from coking the bearings and killing the turbo......best thing to do is let it idle for a minute after normal driving and 3-5 after really hard driving....turbos get extremely hot and retain heat because of their location....you want the turbo to be as cool as possible after running hard....this has nothing to do with engine temps....the turbo will always be hotter than the engine....its just a matter of getting it as cool as possible....let it idle all you want....itll never be too much...just make sure it was enough!....(you can pop your hood also to help)....

n2trbl

paw140 & boostcrzy: Thank you guys for you help. (and the rest who posted before them just the same) With all the answers I've been getting about turbo timers I've decided not to waste my money on one. I didn't even consider the alarm. I just couldn't ever walk away from my car and leave it running. Poping the hood is a good idea! I can't believe I never thought of that. I feel alot less worried about overheating me car. I guess I got worried after all the horror stories I hear about people losing the motor due to lack of cooling. I love this site. Thanks everyone!

Toadman

Don't waste your money on a cutesy little turbo-timer. It's just dash clutter anyhoo. FD turbos are water-cooled, so two minutes before your destination, chill out, kick in the fans(or parking lights if you don't have the fan mod), crank up the tunes and stay off boost as the oil cools and idle for 30 secs when you park.

ZeroBanger

Rule #1: Research this site and learn alot.
Rule #2: Disregard 95 pct of what you read.

Most everyone has great intentions, but the fact is there are no real answers for alot of the questions.

For example, my car has the OEM turbo's, I bought the car last march, my turbo's are the OEM with 155K, the engine lasted until 110K. Now with that said the previous owner never idled his car after he parked. He had NO idea he should.

Now with that said, I dont boost the last 2 mintues, and I wait bout 30 seconds after I park (with the fan on high).

Nice day.

Kahren

iTrader: (13)

i would be more worried about eh car overheating sittign tehre idling unattended then havign teh turbos go bad faster. even if u ahve the habbit to beat teh crap out of your car tehn imiately park it and shut it off.
hell thats prolly bad for a NA car . like was stated previously drive like a grandma for last couple of miles aor 3 to 5 mis and u will be fine. idling the car only builds up lots of carbon that u will loose teh engine to if one of those pieces flakes off and gets stuck in your apex seal

skunks

when you turbo time, you should have your fans manually turned on high! Personnaly I always turbo time about 2 mins-10 mins depending on how hard i just ran the turbos, if you cruise with fans on for about 1-2 mins before you shut the car off, just shut it off and pop your hood to cool it down a bit (unless you got a scoot hood... This actually might not be such a good idea though since recent test with my brother's car shows that it turns out its not exactly that good at venting all that heat... Yes, yes it does have those huge vents but they are not as good as one would think at venting)

The only time I personnaly don't turbo time or pop my hood to cool down after a hard run is when I'm running from the cops; After I do, I just shut it off, throw a cover on my car and run away. (Only had to do this 2X so far, once was today at around noon hehe shhhhh)

n2trbl

Thanks guys. I can't believe more replies are still coming in. I thought this subject was totally worn out by now. Just goes to show what kind of people are on this site (that's a good comment) I decided not to get one at least so far. I know this may be stupid (I feel stupid asking) but I hear alot of guys talking about running their fans? Do they kick automatically? I've never had them on. Toadman said something about using the parking lights if I didn't have the fan mod? My fd is stock still since I just got it a few weeks ago so I don't have any mods. Please don't make fun of me too much. Go easy on the newbie Thank you guys for all your help and comments.

spurvo

my $0.02 (long ***, mostly noob response):

So the other day I hooked a thermocouple to the turbo housings. I drove around under non boost condition, wherein the boost gauge reads under 8 inches of vacuum most or all the time as you drive. Turbos spool up depending on throttle position versus load. Low RPM with large throttle input equals high boost (and eventual boom. Stop it!) whereas higher RPM (like 4500) with light throttle input (just giving a little gas) will give less boost, maybe no boost at all (stays under 0 psi), but still accelerates. Anyways...

After loafing it, I saw the turbo temp was around 450C (REALLY, I mean celsius!). This was with the engine temperature at the thermostatic minimum, or 177F. So as was stated above, the engine temp (in this case, read from the stock position (under the oil filter) with a linearized gauge) does not equal the turbo temp, not even close in fact. Further, I noticed that shutting down after a 45 second idle with the turbo at this temp gave lots of nice gurgling right from the top of the engine as the coolant boiled. I figure the oil was toasting nicely too... On top of this, I monitored the engine temp versus turbo temp after shutoff. The engine temp started climbing, went to 210F or so (can you say heat soak? I knew you could..), while of course the turbo temp dropped (no more exhaust flowing).

So I did this again, but this time let the car idle for a "while". I noticed that after about 1.5 minutes, the engine temp gauge started to rise (duh!). I look over at the turbo temp, expecting 500C. Nope. 390 C and dropping fast. By the time the engine had reached 205F, the turbo was at 350C. Then I turned the fans on to low (LOVE the fan mod. Fan mod RULES!!!), brought the engine temp back down to 177F. As soon as the T-stat closed, the turbo temp stopped dropping, and actually started to rise again. Ohhh....

I deduced from this that the super heated coolant from the turbos mixes poorly with the engine coolant in the absence of a large heat sink available (i.e. radiator cut off by T-stat). So this led me to try the following. Park the car with the engine running, let it idle until the engine temp starts to rise. Turn on the fans at 200F or so, and let it drop to the 177F. Let it idle some more (here many of you will say WASTE of TIME! Maybe... but read on) until the temp reaches 200, and kick on the fans again. I typically do this for three cycles. When I'm finished, a 500 C turbo temp (a little spirited driving) is at 305-325C, engine temp is at 177F. I shutoff and watch the temp gauge to see heat soak. It moves to a WHOPPING 189F. Ahhh... where's that gurgling?

Note: keeping the fan on AFTER shutoff does NOTHING!!!!! heat soak is from the hottest part of the engine, which is the exhaust/turbo assembly. With engine shutoff, coolant no longer circulates (a little convectional flow maybe, but certainly not enough to cool the engine!) through the water pump to turbo housing and back to water pump and out to radiator if the T-stat is open (which it is at 189F). Running the fans after shutoff for ten minutes as per the traditional fan mod may just be abetting the heat death of the universe... but I see no difference with it on versus off, though the battery and SMIC get hotter, then cooler as the radiator reaches ambient (about 5 minutes of fan operation).

So that's my bullshit. An intelligent turbo timer would cycle the fans, not allowing the engine temp over 205F to limit thermal expansion and contraction (and therefore prolong weak O-ring life), and monitor the turbo housing temp, and shut off once the turbo is at a specified temp and the engine is at 177F. Usually this is a 5 minute process. Lucky me with a garage, I pop the hood and leave it open, too. And put on a DP. And a Fluidyne radiator. And an aluminum AST. And all coolant hoses replaced. Yadda yadda..

Thank you for reading this far. Your bullshit meter may be pegged, for which I apologise. I should go do something productive now....