What temp is too hot to shut down?
06-30-2018, 12:48 PM
#1
Pro
Thread Starter
What temp is too hot to shut down?
I know it's best to let oil circulate before shut down but what oil temperature is considered too hot? My car never really is run hard enough to get over 225deg. I usually like to cool it off as I get closer to home and shut it down, most times, under 200. Is this too conservative?
06-30-2018, 01:30 PM
#2
RL Community Team
Rennlist Member
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2009 C2S 125K miles
Good question!
I let the temp "stabilize" so if i'm running hard and know I going to park, I purposely go easy and let it cool.... staying in a higher gear with lower revs speeds the cool down (looking at oil temp of course... only thing we have). I am amazed at how fast this can happen... I don't have a center radiator and the cool down can happen in just a few minutes, even in hot weather.
A year or so after I purchased my Datsun 2080ZXyzlmnoq Turbo, I received a letter from Datson about letting my oil cool before shut down... this was to prevent "coking" or the cooking of oil in the turbocharger. I don't remember what exactly the procedure was but it was let the car run for a few minutes at idle after running the car hard... or something like that. But the car had a another problem: vapor lock. If you shut down a hot engine, the gas would boil in the injectors and the car would not start. The dealer dealt with it by permanently turning on the this fan that had two vents that blew directly on to the injectors to prevent this. The fan was only supposed to come on in extreme conditions but they set it to run for a few minutes after every shut down regardless. So.... from this experience, I realized that it may never be a good idea to shut an engine down hot. True? I dunno.
Peace
Bruce in Philly
Good question!
I let the temp "stabilize" so if i'm running hard and know I going to park, I purposely go easy and let it cool.... staying in a higher gear with lower revs speeds the cool down (looking at oil temp of course... only thing we have). I am amazed at how fast this can happen... I don't have a center radiator and the cool down can happen in just a few minutes, even in hot weather.
A year or so after I purchased my Datsun 2080ZXyzlmnoq Turbo, I received a letter from Datson about letting my oil cool before shut down... this was to prevent "coking" or the cooking of oil in the turbocharger. I don't remember what exactly the procedure was but it was let the car run for a few minutes at idle after running the car hard... or something like that. But the car had a another problem: vapor lock. If you shut down a hot engine, the gas would boil in the injectors and the car would not start. The dealer dealt with it by permanently turning on the this fan that had two vents that blew directly on to the injectors to prevent this. The fan was only supposed to come on in extreme conditions but they set it to run for a few minutes after every shut down regardless. So.... from this experience, I realized that it may never be a good idea to shut an engine down hot. True? I dunno.
Peace
Bruce in Philly
06-30-2018, 01:53 PM
#3
bruce
i have right hand drive cars directly from japan
almost all cars has a shut off timer on all skylines
that tells you something with the turbo as you mention
give them a minute before shutting down
when you have a good rev run, just easy on the right right foot when you are going home
i remember my track and field coach told me not to just stop completely after a 100 meter dash
make sense
cheers
06-30-2018, 02:26 PM
#4
With a turbo running tens of thousands of rpm, I don't like the idea of removing the oil supply until the turbo spools down.
Look up turbo timer ... keeps the motor running at idle for a specified time after shut down to prevent coking. I suspect they are still available.
I used these in the 80s and 90s on Lotus turbos. Didn't install one on the Supra TT. Gave that to Pam for a while. Got it back with two seized turbos. My fault ... failed to mention spool down. It's a real thing and a problem.
I was worried about the "in traffic automatic motor shut off" when we bought Pam's new car. The people at the AMG factory insisted that new bearing and oil technology removed these concerns. I was also told that the AMG turbo spins to 100Krpm. As you may imagine, I remain skeptical. I generally hit the auto shut off over ride button at start up!!! We cool that car off as we approach the last few mikes of any trip.
In fact, I always cool any car down for a couple miles before shutting down. Learned this from 2 stroke engines in the 60s ... snowmobiles, motorcycles, chain saws, etc.
As a side topic ... I saw oil temps earlier this week at near 275 as we climbed up to 9000 feet over the Sierras. Saw near 250 more times than I can count over the two day drive. Always waited to 225 for shut down.
A note on this (and a previous) trip ... a car with a third radiator held 210 the entire time. Want to guess what I'm thinking for a mod?
Look up turbo timer ... keeps the motor running at idle for a specified time after shut down to prevent coking. I suspect they are still available.
I used these in the 80s and 90s on Lotus turbos. Didn't install one on the Supra TT. Gave that to Pam for a while. Got it back with two seized turbos. My fault ... failed to mention spool down. It's a real thing and a problem.
I was worried about the "in traffic automatic motor shut off" when we bought Pam's new car. The people at the AMG factory insisted that new bearing and oil technology removed these concerns. I was also told that the AMG turbo spins to 100Krpm. As you may imagine, I remain skeptical. I generally hit the auto shut off over ride button at start up!!! We cool that car off as we approach the last few mikes of any trip.
In fact, I always cool any car down for a couple miles before shutting down. Learned this from 2 stroke engines in the 60s ... snowmobiles, motorcycles, chain saws, etc.
As a side topic ... I saw oil temps earlier this week at near 275 as we climbed up to 9000 feet over the Sierras. Saw near 250 more times than I can count over the two day drive. Always waited to 225 for shut down.
A note on this (and a previous) trip ... a car with a third radiator held 210 the entire time. Want to guess what I'm thinking for a mod?
06-30-2018, 02:43 PM
#5
Three Wheelin'
I have a MKIV Supra Turbo and have a HKS Type 1 turbo timer. So depending on my driving and boosting, it'll calculate the cool down time before shutting down the engine. On any turbo car, to help preserve the motor and turbos, proper cool down is a must.
The Turbo Timer Type-1 features an Auto mode for the timer function allowing the Turbo Timer to automatically calculate optimum idling time according to the most recent driving pattern. Vehicle speed and RPM can be displayed on the Type-1's LCD monitor and a speed warning level can be set. A two-stage RPM warning can also be set and used as a shift indicator. When a warning level is reached the Type-1's LCD monitor will blink and an audible beep will sound. The HKS Turbo Timer Type-1 also features various measurement functions including 1/4 mile timer, 0-60 timer and a stopwatch function that can be used for lap timing. The Turbo-Timer Type-1 can read in either MPH/SAE or KPH/Metric.
On the 911, I don't refer to the manual with the "drive immediately after startup" nonsense and proceed to drive once the RPM needle drops. Since my community has a strict low speed limit, cool down starts from the gate till the time I park it in the garage. It's an NA so there isn't an actual cool down period but a proper cool down period wouldn't hurt.
The Turbo Timer Type-1 features an Auto mode for the timer function allowing the Turbo Timer to automatically calculate optimum idling time according to the most recent driving pattern. Vehicle speed and RPM can be displayed on the Type-1's LCD monitor and a speed warning level can be set. A two-stage RPM warning can also be set and used as a shift indicator. When a warning level is reached the Type-1's LCD monitor will blink and an audible beep will sound. The HKS Turbo Timer Type-1 also features various measurement functions including 1/4 mile timer, 0-60 timer and a stopwatch function that can be used for lap timing. The Turbo-Timer Type-1 can read in either MPH/SAE or KPH/Metric.
On the 911, I don't refer to the manual with the "drive immediately after startup" nonsense and proceed to drive once the RPM needle drops. Since my community has a strict low speed limit, cool down starts from the gate till the time I park it in the garage. It's an NA so there isn't an actual cool down period but a proper cool down period wouldn't hurt.
06-30-2018, 04:29 PM
#6
RL Community Team
Rennlist Member
Rennlist Member
Peace
Bruce in Philly
06-30-2018, 05:05 PM
#7
FWIW, other (modern) cars I've had heat up pretty much the same regardless of ambient. I remain suspicious of the 997 cooling system, but I've gone down that road many times on this Forum.
I'm debating smiley face to extract air from behind the third radiator if/when I add it. But then I'd feel like a GT3 poser.
I need to spend some time getting smarter.
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06-30-2018, 05:40 PM
#8
Rennlist Member
I have a MKIV Supra Turbo and have a HKS Type 1 turbo timer. So depending on my driving and boosting, it'll calculate the cool down time before shutting down the engine. On any turbo car, to help preserve the motor and turbos, proper cool down is a must.
The Turbo Timer Type-1 features an Auto mode for the timer function allowing the Turbo Timer to automatically calculate optimum idling time according to the most recent driving pattern. Vehicle speed and RPM can be displayed on the Type-1's LCD monitor and a speed warning level can be set. A two-stage RPM warning can also be set and used as a shift indicator. When a warning level is reached the Type-1's LCD monitor will blink and an audible beep will sound. The HKS Turbo Timer Type-1 also features various measurement functions including 1/4 mile timer, 0-60 timer and a stopwatch function that can be used for lap timing. The Turbo-Timer Type-1 can read in either MPH/SAE or KPH/Metric.
On the 911, I don't refer to the manual with the "drive immediately after startup" nonsense and proceed to drive once the RPM needle drops. Since my community has a strict low speed limit, cool down starts from the gate till the time I park it in the garage. It's an NA so there isn't an actual cool down period but a proper cool down period wouldn't hurt.
The Turbo Timer Type-1 features an Auto mode for the timer function allowing the Turbo Timer to automatically calculate optimum idling time according to the most recent driving pattern. Vehicle speed and RPM can be displayed on the Type-1's LCD monitor and a speed warning level can be set. A two-stage RPM warning can also be set and used as a shift indicator. When a warning level is reached the Type-1's LCD monitor will blink and an audible beep will sound. The HKS Turbo Timer Type-1 also features various measurement functions including 1/4 mile timer, 0-60 timer and a stopwatch function that can be used for lap timing. The Turbo-Timer Type-1 can read in either MPH/SAE or KPH/Metric.
On the 911, I don't refer to the manual with the "drive immediately after startup" nonsense and proceed to drive once the RPM needle drops. Since my community has a strict low speed limit, cool down starts from the gate till the time I park it in the garage. It's an NA so there isn't an actual cool down period but a proper cool down period wouldn't hurt.
06-30-2018, 06:14 PM
#9
Three Wheelin'
What's funny is that I have a turbo dakota digital fan controller on my Boxster that I used to track along with a cayenne V6 aux water pump (electric) that would continue to circulate the coolant and keep the fans running, even with the engine off. That way I could run back to back sessions and the 5 minutes between sessions was enough to cool the engine down. Worked like a charm.
