Should I go synthetic?

[donstevens]

Originally posted by livi


But what about all the small metal parts and dirt that is suspended in the oil posing a threat to the internal engine parts ? Would the accumulation of such debris not be the same with any kind of oil and hence make an important factor for drain intervals ?

This is a valid concern but anthony is right, they will get caught by the filter up to 10000-12000 miles. The pieces that are too small for the filter are relatively inconsequential to wear. We are talking about wear metal in parts per million here. Sure a car that goes 10000 miles on oil might have 30 ppm of iron in the oil where a car that goes 3000 miles may have 10 ppm. Most oil analysis labs don't even flinch at 100ppm so the extra wear from 10 - 30 ppm in the example is not significant relative to the longevity of the engine.

Long drain intervals have been proven safe (as supported by oil analysis data) in thousands of vehicles over millions of miles based on cars with 5 qt sump capacities. Many of these are large V-8s with much piston/cylinder area than our cars have and 1/2 the oil capapcity. Our 10 qt plus oil capacity and realtively small friction areas in the engine arguably allow the oil to disperse even more microscopic metals.

This is another reason for used oil analysis. This will reveal how much additional wear YOU get in YOUR car based on YOUR oil and YOUR driving style/conditions. It absolutely eliminates guess work and speculation.

Don

[sammyg2]

This is a high mileage street engine, right?
Sure, go ahead and throw money down the drain by using synthetic oil. If you're lucky you might even be able to rationalize it with some reason, no matter how irrational or how much of a stretch it is. Lots of others have managed to justify it.

BTW, i run synthetic just because i have a turbocharger, otherwise i would keep my money in my wallet where it belongs.

[island911]

turbocharger! . . .on a high mileage street engine? ....

(Now what was that about "justify & rationalize"?)

[sammyg2]

LOL my engine is no longer a high mileage street engine, it was gone through about 3000 miles ago so now i can rationalize that it is a new engine (not really, that was humor)
And yes, there was quite a bit of rationalization involved in the decision to install a turbo. the easiest argument with myself was hp per $.

I figure a set of SSIs and a good muffler would set me back a grand and get me an increase of somewhere in the 10 hp range after deducting all the exaggerations. That's $100 per hp gained.

My turbo has netted me somewhere between 70 and 100 hp increase (no dyno yet so i leave a lot of room in that range) for around $1200. That's about 9 times more economical and effective than headers. Being a cheap SOB, that made more sense to me

Plus the results of the turbo install are real, obvious, and measureable. Changing to synthetic may or may not have benefits that justify the extra money, if it does they would be very hard to measure.

[911Velocity]

Each to his own but I have used Amsoil racing synthetic on all my vehicles since 1987. Some of them I bought new and others used. I never had any leaks that weren't already there. The syns all now have additives that theoretically prevent this. I change oil filters between 1500 and 3000 miles depending on the vehicle and driving manner. Syn will help save you in the case of catastrophic failure of the cooling system (syn won't coke at temps that fry dino) and I have experienced this on several occasions but not with the Porsche. The miles on all of my vehicles is extremely high with 587K on my Toyota PU but I am sure some of that is due to good engines. In the end it is your choice with lots of advice on both sides of the issue. Good luck.

Best regards,
Gerry