Depends on how long I plan on running the mix and under what conditions and the kind of oil I have on hand. Usually, If I'm going to mix, I'll add 1 quart of syn. to the Dino to beef it up a bit. Last spring I ran 4 qts of Exxon 5w20 & 1 quart of M1 0w20 for 4k in the wifes' van.
As I mentioned a billion times before....A quart of RL. I have mixed it with Havoline Dino, Motorcraft, MobilDC, Mobil 1, Castrol DC. I have recently done 2 runs on Mobil 1/Redline at 5K and 5.5 K miles (just sent in the last one).
I now have TropArtic/RL in there and am anxious to see the results. After this run, I might go to one without the RedLine. That will be mentally hard to do bc I believe the results show that RL mix does a good job. I was fortunate to buy out the 25 quart supply of Advance's RL at an average of $3.50 a quart.
1 qt - 24 oz of synthetic
3 qt - 8 oz of dino
Then dump the 8 ounces synthetic into the 24 ounces of dino remaining -- shake well & viola.... an instant syn-blend quart for top-offs.
Obviously, this requires you to purchase six quarts. It gives you a real nice 33% syn-blend.
If you only wish to purchase five quarts & use full quarts for your blend, you can choose from any combination of 20-40-60-80% blend
[ April 24, 2006, 12:12 PM: Message edited by: Triple_Se7en ]
I haven't done this for several years now, *but*: back in the "bad ol' days" before I found BITOG, did it for a while in the Neon. I was changing oil at 3K, racking up about 750-900 miles a week at the time. Remember, this was pre-BITOG. I used 3 to 3 1/2 qts conventional, i to 1 1/2 qt "synthetic". Yes, "synthetic". I didn't know any different at the time, & thought synthetic meant synthetic. I'll give you three guesses as to what brand it was, & the first two don't count. (Hint: what brand convinced a judge, who knew zip about motor oil, that Group III oil should be called synthetic?)
It worked OK, but probably no better than the same brand's "synthetic" blend did. I did no OA back then, & so have nothing to compare it to.
If I were to do it now, I'd use something known to be a real PAO or Group V synthetic, and probably use 2 qts synthetic to 3 qts dino. JMO.
Another "pre-BiTOG" mix....
At the time, I called it my D.I.Y. Durablend.
3qts. Valvoline All-Climate 10W30
1qt. Valvoline Synthetic 10W30 (pre-Synpower)
...then Valvoline came out w/Maxlife. I've used it almost exclusively ever since.
Just made my blend this weekend.
1995 Honda Accord EX 4cyl VTEC
3 quarts Havoline 5W30
2 quarts Mobil 1 5W30
Will run it 5k miles, just like I just ran 5 quarts of Havoline 5W30. Topped off with 3/4 quart of M1.