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Registered User
Join Date: Mar 2002
Posts: 3,563
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Are you guys exercising the typical cool-down procedure on your turbo's, even if you haven't driven the car hard?
My understanding is that you should let the engine idle for ~2 minutes after a hard run (e.g: frequent max boost bursts), but if you haven't been driving the car hard at all (i.e: no boost), is it safe to just shut off immediately? Is this a bad thing?
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition ![]() |
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Me like track days
Join Date: Sep 2003
Location: Kirkland, WA
Posts: 10,205
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I let mine idle for a few minutes after any drive - the heat is just unbelievable, even after a modest run....
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- Craig 3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ - "930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe Movie: 930 on the dyno Last edited by Craig 930 RS; 12-04-2006 at 11:13 AM.. |
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resident samsquamch
Join Date: Oct 2005
Location: Cooterville, Cackalacky
Posts: 6,815
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I usually let mine cool down, too. Cool down for me is probably closer to 1.5 minutes. I use it as an opportunity to look underneath the engine, while it's running, to check for leaks and what not. My car sees mostly short bursts and I usually have an opportunity to drive it like a little old lady (low RPMs, no boost, 1st or 2nd gear) before I park it for the cool down period.
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-jeff back in the saddle: '95 993 - just another black C2 *SOLD*: '87 930 GP White - heroin would have been a cheaper addiction... "Ladies and Gentlemen, from Boston Massachusetts, we are Morphine, at your service..." - Mark Sandman (RIP ![]() |
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Registered User
Join Date: Mar 2005
Location: Taxachusetts
Posts: 159
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You should always do a cool down. The length of time depends on how hard you drove the car. After races, I would idle for 7-8 mins.
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- Colin GTC Motorsports, PCA Club Racing National Scrutineer '92 Euro Cup #96ZNS498058 (PCA GTC1 #19) Past '91 C2 Turbo (PCA D Class #38), '04 Cayenne S, '74 914-6 3.2 (236rwhp), '02 986S M030, '71 914-4 2.1, '76 914-4 2.0 |
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Registered User
Join Date: Mar 2002
Posts: 3,563
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Thanks... yeh, I'd have to say I take it easy the last 3-5 minutes before reaching final destination, then let it idle down a further minute and shut off.
I did that with my KKK for years and had no issues. Now that I have a GT BB turbo, perhaps I need to be a bit more cautious, since it hasn't got water cooling hooked up ![]()
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition ![]() |
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Registered User
Join Date: Jun 2006
Location: Ballston Spa, NY
Posts: 528
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Quote:
Local garrett Dealer here ![]() All turbochargers should be "timed" no matter what the driving condition is for maximum longevity. If one is in a hurry and doesn't want to wait in the car, a good turbo timer module should be wired in for use to prevent coking(burnt oil residue buildup) which will eventually restrict oil flow. The HKS type I and II units are very good, reasonably priced(~$100-$120), and have an auto time function that determines the proper time down setting based on the car's recent driving situation(oxygen sensors referrenced). Takes the "how long" guesswork out of the equation ![]()
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Adam Hennessy |
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Registered User
Join Date: Mar 2002
Posts: 3,563
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Thanks for the feedback BoxxerSix.
I do have a Greddy unit lying around, which I probably should have installed soon. That'll save me from sitting in my car in 90+ degree heat waiting for the cool-down process to finish ![]()
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition ![]() |
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OFF THE BOOST PIPE NOW...
Join Date: Oct 2003
Location: Mount Pleasant, South Carolina
Posts: 8,657
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There's something about walking away from my car with it running with a timer to cool down the turbo while I'm not there I don't like.
I can just see it bursting into flames while I go into the house and start watching TV... Last edited by A930Rocket; 12-05-2006 at 05:29 PM.. |
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Me like track days
Join Date: Sep 2003
Location: Kirkland, WA
Posts: 10,205
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When I pull back into the driveway, I just use the cool down time to pick up leaves, get the mail, check the oil level, or even to see the jackass neighbor leaf blowing his leaves into the road.....
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- Craig 3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ - "930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe Movie: 930 on the dyno |
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Registered User
Join Date: Mar 2002
Posts: 3,563
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What happens when you get home at some unGODly hour in the morning? Wouldn't make you too popular with the neighbors eh?
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition ![]() |
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Registered User
Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
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It's also pretty unpractical to impossible when taking girls out on a date.
They won't want to sit in the car and wait for that, unless your making out or something... If you drive slowly and shift at lower revs and don't get into the boost at all for the last few minutes of driving and use synthetic oil.. I don't think you'll have a problem turning it off like a regular car. I may be wrong though. |
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Forced Induction Junkie
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Dave '85 930 Factory Special Wishes Flachbau Werk I Zuffenhausen 3.3l/330BHP Engine with Sonderwunsch Cams, FabSpeed Headers, Kokeln IC, Twin Plugged Electromotive Crankfire, Tial Wastegate(0.8 Bar), K27 Hybrid Turbo, Ruf Twin-tip Muffler, Fikse FM-5's 8&10x17, 8:41 R&P |
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Registered User
Join Date: Dec 2002
Location: Long Beach, CA
Posts: 1,128
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With modern oils, especially synthetics, I wonder about the need for a "cool down" after moderate driving. After a highway run, or hard drive, I can see that one minute would be helpful. Has anyone really studied this issue, or are we working from intuition and legends from the early days of turbos?
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Me like track days
Join Date: Sep 2003
Location: Kirkland, WA
Posts: 10,205
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I agree. Driven 'mellowly', a shutoff should be fine.
If anything, airflow around the turbo while moving would help.
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- Craig 3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ - "930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe Movie: 930 on the dyno |
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Registered
Join Date: Aug 2005
Location: Michigan
Posts: 3,337
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Yup, me too. I always take it easy the last few minutes before shut down. Just stay off boost by shifting before your turbo starts to spool.
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Bill |
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Registered User
Join Date: Mar 2002
Posts: 3,563
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Yeah, lately I've just taken it real easy the last 2-3 minutes before final destination, then perhaps let it idle down for a minute extra before shutting off.
I think the key to making turbo's last is religious oil servicing.
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition ![]() |
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Registered
Join Date: Oct 2006
Location: Chas, SC
Posts: 1,088
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Wouldn't letting the car idle for several minutes after taking the last 5-10 min easy (say around 2k in 2nd gear) actually cause the oil temp to go up instead of down???
By no means an expert, just asking.. tim.
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Tim 1986 930 Gone:71,2,4 914's, 70T, 71T(RS),77S |
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Registered User
Join Date: Mar 2002
Posts: 3,563
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Quote:
I do notice in the hotter climates, if I sit stationary in traffic, the oil temps rise quickly and the intercooler begins to heat-soak, greatly impacting on power and response ![]()
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Merv '89 911 Turbo Cab Protomotive MAP ECU, Twin Plugged Heads, GT2-EVO CAMs, 3.3L fully finned P&C's, ARP fasteners, C2T head gaskets, Titanium Retainers, Turbo spec valves, springs & guides, 964 splash valves, GT35R BB turbo, GSF Stainless Headers, Magnaflow Exhaust, Full bay Intercooler, TiAL 46mm w/gate, TiAL 50mm BOV, Apexi AVC-R EBC, SPEC Stage3+ Clutch kit, Crane CDI Ignition ![]() Last edited by WydRyd; 12-06-2006 at 03:32 PM.. |
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Brando
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Your cooling the turbo in the cooldown, not the oil. The oil doesn't matter that much in this case. The turbo housing gets pretty hot and takes time to cool. getting out of the boost for a while would help keep the turbo from glowing, and such, but it's still going to spool.
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Turbo powa! 1977 911s. it's cool |
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Registered User
Join Date: Apr 2005
Posts: 24
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As Quattrorunner has just mentioned, it is the heat from the turbine-housing and turbine wheel that we are trying to cool down. It is also the idle circuit that produces the richest fuel when sitting. Thus cooling down the turbine wheel the quickest vs having you foot on the throttle coming home. 1 minute is good 2 minutes great. After that you risk heat soak.. It's interesting to see who is good at cooling down turbochargers when tearing down the turbochargers during a rebuilt.. Having a blue shaft to the compressor side bearing is NOT good.
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