Originally Posted By: EPHIOS
Right now I have been using regular conventional, Pennzoil YB and Castrol GTX. I have enough GTX for 4 more oil changes, after that I am planning to switch to synthetic. I have a 2004 Hyundai Elantra with 48K. Which fully synthetic 5w-30 motor oil do you guys suggest? Plus, will I notice any performance gain (like smoothness, higher MPG and ect.)? Thanks!
I would say if your engine responds the same, to a swap over to synthetic like all of the engines I have done it in, you will notice it runs smoother. You get used to it though pretty quick and it is not something as noticeable after 3-4 days or so. The very 1st OC using synthetic in an engine, any time I have done it, it is noticeably smoother.
Just swapping the engine over to synthetic may yield small MPG gains but to really see noticeable MPG savings you need to swap the entire drivetrain over to synthetic. A FWD 4cyl may not see as much of a gain as say a 4WD pickup. If you just swap the oil you may see a .2-.5 MPG gain as a rough guess. I did a full swap on an 04 HEMI Ram( ie; engine, t-case, tranny, F&R diff's )to synthetics and saw just a hair under 2 MPG highway gain.
As to brands. Well, that is up to you as to how much you want to spend. If money is no object and you want the best then Royal Purple, Redline or Schaffers would be my 3 recommendations run on an extended OCI of 10-15K. I am not sure what your warranty situation is though with a 2004 Hyundai( don't they have that 10/100,000 warranty? )so these oil's and an extended OCI schedule may not be right for you? IF you just want a really good synthetic for more reasonable costs, that you will change sooner, then I would look at PP, Synpower, QS HP( or whatever the new name of the month is - Ultimate Durability? )and Kendall GT1. All 4 of those are availabe for right around $5 a qt and are very good.