Suggestions on oil for 1987 Porsche 930 Turbo..

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Please chime in.. I'm trying to narrow my search prior to my next oil change. Vehicle information: 1987 3.3 liter, K26 turbo, air cooled. Billet cams. 85k on the bottom end of the motor. 15k on freshened heads and turbo. Currently running old stock 15-50 Mobil 1 synthetic Oil filter: OEM or Mahle Oils that I am considering.. Various brands of V-twin oil. New stock mobil 1, 15W-50 Castrol Edge, 10W-30 Other suggestions and reasons why are very much appreciated.
 
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I think Doug Hillary is the person you need to talk to. He is a member on this board.
 
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I would go with the M1 15W-50 for the summer and 5W-40 Euro if you run it in the winter. it should offer better protection than the 10W30 IMHO. it sounds like a nice 911.
 
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Hi, Red930 - A hearty WELCOME to BITOG I have recently been to Zuffenhausen and the Nurburgring and I'll relate some relevant data here for your use The factory Approval List still applies to your engine (>MY84) series - on the List around 65% of the lubricants are 5W-40 viscosity, the balance are 0W-40 - only one SAE50 lubricant is listed M1 5W-50 The largest Factory Delership in Stuttgart ("Porsche Zentrum" - opposite the Musuem & Factory entrance) uses a 10W=40 semi synthetic lubricant in older engine families. Here in Brisbane they use a 15W-40 HDEO M1 15W-50 is popular in older air cooled engines amongst Owners, some privateer racers and in some fleets racing older aircooled engined cars. So is Castrol's Syntec RS 10W-60! One owner of a 959 I spoke with (he also has the latest Carrera 4 - on M1 0W-40) uses M1 15W-50 in it The Factory's Museum uses 10W-40 or 20W-50 in their very valuable old vehicles (956 etc) - heated to 80C before load/revs are applied of course If your car was mine I would use M1 TDT 5W-40 (a conforming Factory stipulated viscosity) or its "relation" Delvac 1 ESP 5W-40 as first choice, Delvac 1300 15W-40 (HDEO) would be the second choice! Best wishes
 
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Red930

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Please give me your opinions on why you choose Mobil 1 versus the newly introduced Castrol Edge. Castrol Edge is a group IV full synthetic and it conforms to the SH, SJ and ACEA standards as well and most others standards. It also claims to beat Mobil in wear testing. Do you not like it because it's not available in the viscosity that I should be running? Is 10W-30 too thin? Thank you for the great replies thus far, Red930
 
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I just feel Mobil 1`s a better constructed oil,but that`s just my opinion. Mobil 1`s silver cap 15W50 is supposed to be a grp IV/V oil while Castrol`s syns are grp III. I`d run GTX over Edge if I were given the choice of Castrol`s lineup.
 
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Hi, Red930 - You need a ACEA A3/B3 lubricant with a minimum of a 3.5cp (preferably around 4cp) HTHS viscosity An SAE30 lubricant has not been recommended by Porsche via TISBs since MY99
 
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My Porsche mechanic builds customer Club Cars and races them head-to-head. I've even been around Watkins Glenn with him driving at a Porsche Club Event. In that realm, Mobil 1 Red Cap is highly shunned, in favour of Syntec 5w-50. I'll go outside that and say Syntec 20w-50 might be a good summer oil and in winter, maybe a 5w-40 with heavy diesel specs like Rotella or one of the Mobil 1 Hi-Miles 10w oils.
 
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Hi, AJ - You are already aware that the Castrol 0W-30 lubricant you show is entirely unsuitable for any air cooled Porsche engine family let alone a turbocharged one It is only Porsche Approved for VW derived Porsche installed engines only!
 
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The oils I would choose, depending on availability & price Redline if the car sees the track, anything from 5w40 up to 15w50 depending on oil temps Mobil 1 10w40 high mileage or 5w40 TDT (non-ESP, for higher zinc content) Mobil 1 15w50 for higher oil temps if you don't want to shell out the $$$ for Redline
 
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And as Doug mentioned, do not run a 30wt oil in that car, especially a GF4 30wt like Castrol Edge. If you must run a 30wt, then use something thicker like German Castrol or M1 10w30 high mileage
 
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I meant to write a bit further on the subject, my mechanic actually uses VR-1 20w-50 in his cars now. Doug, can you be more specific about which engines German Syntec is Approved for, since it meets Porsche's general spec anyway.
 
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Hi, AJ - Castrol's Syntec range is Approved & Listed according to its viscosity. No SAE30 versions are Approved for engines that have a Porsche heritage. Castrol's lubricants in this area include Edge 0W-40 (2), 5W-40 (1) and Syntec 5W-40 amongst others My current List may have been updated but I doubt it! Porsche's vehicles that have a VW derived engine family installed (example Cayenne V6) have a seperate Approvals List - this is structured according to the current applicable VW List. This Porsche List includes four 5W-30 Castrol products. Some lubricants from the "other" List can be used in the VW derived engines according to Marketplace availability and these include two Syntec 5W-40 versions. My List in this area may have been superceded Most Porsche Approved lubricants have an Approval expiry date - this is now a three year window. Some minor reformulations can occur in the window and some will "fall off" the availabilty List - some may be added too of course Monograde SAE30 HDEOs were used in Porsche engines as a FF for many years during the 1950s-1970s - maybe longer. I used a 20W-20 HDEO CAT 3 Approved lubricant in the Porsches I was involved with in Scandinavia during the Northern winters. Synthetics were used as the FF from 1992 onwards - firstly in a 10W-30 viscosity and this was superceded (after 12 months) by 5W-40 and then 0W-40. This viscosity (M1 0W-40) has been the FF now for almost a decade The Factory Museum uses 20W-50 mineral lubricanst in some of its Classic race cars. This lubricanst is always warmed to 80C at very low revs (under 1800) before any load/revs are applied. Somes cars get 10W-40 and 15W-40 IME older dry sump aircooled engines in "nornal" use are best to use a 15W-40 HDEO (according to the prevailing ambient) (or a monograde SAE30 HDEO)- these lubricants cool components better than a SAE50 and are easier on the oil pumps and less prone to foaming etc
 
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