Originally Posted By: ekpolk
Originally Posted By: zoomzoom
Originally Posted By: ekpolk
Originally Posted By: Epic_
Are you guys driving cars with punched out Briggs & Stratton engines making 12hp? Out of all the oils I have used (M1, RP, GC, Amsoil, GTX and others) in all the difference vehicles I service (Toyota MR2 Turbo, Toyota MR2 [non turbo], Toyota Camry V6, 2.4 Nissan Frontier, 1.8 Nissan Sentra, Lexus IS300, Chevy suburban, 1.5 Mazda Protege) I have *never* felt any difference in performance or mileage.
Even my weak piece of [censored] Mazda.. probably 70whp.. feels completely normal with GC in the sump and has returned consistent 35mpg city mileage with occasional spikes to 37mpg.
I think it's all in your heads. Your butt dynos aren't that sensitive
In a lot of cases, the contrast may be so slight as to be undetectable by mere human butt dynos. On the other hand, I tried an experimental fill of GC (as others have mentioned, slightly above 12 cSt), followed by a fill of PP 0w-20, only 8.4 cSt. This generated a noticeable subjective difference in the engine, but most notably, I could immediately see a jump in the mpgs as measured by the computer. I had one mostly I-10 trip on the fresh PP on which the measured mileage spiked to 39 mpgs, whereas with the much thicker GC, I was generally unable to slog out of the mid-low 30s. I guess I'll have to start again logging every-fill mpg info so I can state these things with more precision.
I don't doubt that some drivers subjective observations are a result of subconscious suggestion. ON the other hand, I'm fully convinced that many others, particularly those experienced with cars and their behavior, can feel sluggishness from too thick an oil (or the lack thereof upon a move to a thinner product).
Don't put to much faith in computer calculated mpg...do it the old fashion way..gallons in / miles driven
I pretty much agree. I got lazy after a couple months with the TCH since I was finding that the the ECU mileage was consistently closer to calculated than I expected. Unlike the Prius, the Camry does not have the infuriating elastic bladder in the fuel tank, so it's very easy to consistently fill right to the cap (so long as the pump has a "loose" click-off). I was typically seeing the ECU mileage reading as from one mpg low, to maybe two mpg high.
I think I'm going to start doing manual calculations again, however, so that I can better answer questions like this one.
Edmund's did some fuel sipper testing and found that on baord computer mileage readings are junk:
Not surprisingly, the onboard fuel economy gauges also differed from reality. While the others ranged from 1 mpg better than reality to 3 mpg worse, the Toyota Prius was woefully inaccurate. On the back-road route, the Prius' computer claimed it was getting 6.8 mpg (14 percent) better than it actually was, while the city yielded a 5.4-mpg (11 percent) over-report. This sort of shenanigan could mean a higher customer satisfaction score from owners who think they're getting better mileage than they actually are. This is a shame given the Prius' actual fuel economy dominance.
