Oil Viscosity

[phillyb]

Stick with the recommended oil weight for your vehicle. Using too heavy of oil adds stress to the engine, whereas too light of an oil won't stick to the critical parts in your engine and therefore provides no protection. Both of those can cause an increase in engine temperature. If the cap or manual says 5w30, choose 5w30.
After installing aftermarket parts, the recommended oil viscosity may not be enough. In the case of a turbo system being installed on a 1.6L Honda Civic, I would recommend using a 5w40 full synthetic diesel oil. Why diesel oil? Diesel oil is designed to do more than just protect the engine and reduce heat. This type of oil will clean the engine much better than oil not designed for diesel. Most diesel engines today come stock with turbo. If your engine has a turbo, especially aftermarket, switching to this type of oil will improve performance, allow you to get the most out of each horsepower, improve fuel economy, reduce engine wear and wear on the bearings, and keep the engine cleaner. If I was to turbo my car, I would probably use Valvoline's Premium Blue Extreme in a 5w40 viscosity.
As a side note, consider purchasing a turbo timer. This will allow the engine to idle for a set amout of time (1, 2, 5, or 10 minutes) after you "turn off the engine". This allows the oil flow to the turbo to stabilize and will reduce wear and failure of the turbo. The turbo is going to cost a lot, you shouldn't have to buy more than one. Alternatively, let the engine idle for a few minutes before turning off, especially after you've driven the car pretty hard. (If you just ran a quarter mile at full power, before you park the car, you might want to let it run about 5 minutes). Again, this is only relevant to vehicles with turbos. Don't waste your gas or time like that in a naturally aspirated car.

Phil

[nkwasley]

Is synthetic oil better 5W-30? Why or why not? What is the differance?

[donsoil]

Originally Posted by nkwasley

Is synthetic oil better 5W-30? Why or why not? What is the differance?

Greetings !
The term synthetic is being used very loosely these days.
Synthetic oil used to mean chemically engineered oil.
Now that the big oil companies have hydrocracked /isodewaxed their conventional motor oils, the council of better business bureas' National advertizing division has ruled several years ago that synthetic is now just a marketing term when applied to motor oil.
There are 2 types of synthetics on the market today, one is the original chemically engineered synthetic which is a group 4 chemically engineered basestock, and the "NEW" synthetics which are group 3 basestocks that are conventional oil that has been refined one step further in a process called hydrocracking/Isodewaxing.
This process does improve the lubrication quality versus conventional basestocks, and costs a lot less to make than chemically engineered synthetics, unfortunately in many stores they are priced nearly the same as a chemically engineered oil, and if you check the ASTM test results on the oil specification sheets, you will see the difference in performance.
A majority of "Synthetic oils on the market today are group 3 hydrocracked/ isodewaxed petroleum base oil.
If you seek out and find a chemically engineered oil, in most cases it will outperform conventional oil, and the "NEW" synthetics by a wide margin in the areas of wear, viscosity index, volatility, oxidation, cold flow, and shear stability.
Hope this is helpful !
Have a great day !
Don