oil for 03 SVT Cobra

[Jtgrant]

I am a BMW Master Tech. love this forum. Have a few questions.

I have a 03 Cobra with an upper pulley, tune and supporting mods. The factory spec for this engine is 5w20. I realize that engine oil weight is based off of engine type, builder recommendation, max oil temperature, tolerances, etc.

From my research it seems that CAFE was primarily the reason behind lighter oil. I don't think a 5w20 oil can with stand high oil temps with high rpm and an engine that makes approx 100 more RWHP over factory.

I have been using GC 0w-30 (winter) and 0w40 (summer) in my car. With 4k to 5k intervals, I now that its overkill but I get oil cheap. I was thinking of using BMW 5w-30 next(get it for 4 bucks a quart) I have seen UOAs of BMWs with 15000+ miles on this oil and they look awesome. But completely different engine.

Could I use Mobil1 15w-50? The car has a 170 T-stat and I can monitor all the PCM PIDs, but I currently do not have an oil temp sensor. The car is a DD right now until I can find another DD. Car sees a mix of Higway and City driving with many WOT pulls.

Any advice would be much appreciated.

Edit: I alternate between Lucas UCL and MMO at every fill up and use Chevron Techron every 4-5k miles just before an oil change.

 

[Jason_M]

4.6L engine?

You are correct in that Ford went with 5W20 Syn Blend for primarily CAFE requirements as it offered better fuel economy and did not have any issues with burn off or performance.

5W30 would be fine for this engine, and Full Synthetic would be best. BMW Genuine MO? That is made by Castrol and bottled for BMW. The BMW oil does have different additive packages than other Castrol Synthetics, so you can compare BMW to say Syntec.

Castrol Edge 5W30 would be good choice, PZ Platinum or Ultra would be great as well. You don't need a euro spec like you do in the BMW.

Motorcraft makes 5W-30 Full Synthetic, which is very good product and low priced. I think Wal Mart sells it in quarts.

 

[Chris Meutsch]

A full syn 5w20 will be fine in this engine. It's not an alcohol funny-car. M1 EP, Ultra, or even PP for shorter 5k runs would be fine by me but it's not my Cobra.

 

[tig1]

I believe I have read here that 5-20 keeps oil temps a little lower than than heavier oils.

 

[panthermike]

My girlfriends grandfather owns an 02' Lightning that puts down 500 to the wheels. He's only ran 5w20 Mobil 1 and never had any issues. A 5w30 would work too though.

 

[aquariuscsm]

What about a 5W50 like the Ford GT specs? You have the cold cranking of the 5w20 and the high heat and stress protection of a 50 weight.

 

[aquariuscsm]

On the 5W50 note,does this grade only come in synthetic (pao,ester) or can this wide spread be a dino grp III?

 

[ThirdeYe]

Castrol Edge 5W-30 would be an excellent compromise. It's in the low-end of the 30-grade spectrum so it could be technically considered a thick 20-grade.

 

[mechtech2]

With 100 extra HP, it is smart to consider a heavier oil than the normally recommended 5-20.
But don't go crazy jumping right to a 50. 5-30 or maybe 5-40 .

That 170 Thermostat can allow more ignition advance with your tune and maybe more power, but that is for your dyno pulls and racing.
It is much better for a street car to use a 185-195. Thermal efficiency and gas economy will be better, and possibly engine wear.

 

[racecougar]

To the OP: I have a relatively similar engine setup as you. After the advice I received in this thread , I switched from straight M1 5W30 Truck & SUV over to a 50/50 mix of M1 5W30 Truck & SUV and M1 5W40 TDT (almost 4 qts of each). That raised my hot idle oil pressure from 15 psi to 20-22 psi, which I'm more comfortable with, and has not had a noticeable effect on the oil pressure at max rpm (7000 rpm).

I'd either run a mix of 5W30 and 5W40, or straight 5W40 in your Cobra.

-Rod

 

[racin4ds]

I just filled my 03 Cobra up with PU 5w20 and have about 1200 miles on it so far with no issues. Motor is quiet and runs just fine, I'd really like to be able to see oil temps and actual pressure though... I have a 2.76" upper pulley, Cold air, SCT tune as well. Since it has been a really hot summer and I do plan to make a few passes at the strip this year I am regretting going with such a thin oil, really wishing I would've at least put a 5w30 in her but we will see