After reading last night that semi synthetic oil is actually just a mineral oil which has been cooked in a special pot I have decided to finally try synthetic. Not that I am a fast guy.. more into longevity, a clean engine, and fuel efficiency (and I am not going to tell you how good these things are because you will ridicule me too. Enviro-Tab - GP Forums Cars, Bikes & Motorsport)

Being that I am sold on Amsoil for my motorcycles ntm wishing to recognise Mr Albert Amatusio's contribution to the world of "Synth" I will be sticking with that brand. I live in a very moderate climate and whereas pierce has suggested 10W30 the dealer is pushing me towards 10W40.. saying more zinc better for your turbo. Is this just sales talk? Thanks for your thoughts.

 

with a full synthetic, you could use a 5w30, but I'm not sure I'd use 10w40. the 2nd number is the effective weight of the oil at operating temperatures, which tend to be 220-240F (oil usually runs a little hotter than the coolant). I've been using Mobil 1 10w30 for years without any issues.

zinc is bad for catalytic converters and all modern car oils have much less of it than they had in the past

re: motorcycles, I'd as soon use Golden Spectro than amsoil. my bike uses 20w50

 

Just the man I wanted to talk to. Pierce why don't you use the 5W30? Is it to to with the ambient air temperatures up on the left coast. What lattitude? I may actually look at the Mobil 1. I am not quite as loyal as I was after contacting them about clunky gear changes when the Kawasaki got hot. A sense of we are too important to be talking about this to little people.

 

yeah, we hardly never get below-freezing weather here on the central coast (Santa Cruz to be specific. mild weather R us...).

my 1992 740T owners manual says 10W30 is suitable for -4F to 104F regular operating temperature range. 5W30 is rated for deep subzero to 68F, however modern full synth 5W30 is rather better than that. The owners manual recommends 15W40 for severe driving conditions such as high speed driving, mountain roads with hard engine deceleration, etc, but it must not be used below 5F.

 

Pierce congratulations on your America's Cup win.

I came across the word "groggy" in an oil viscosity discussion somewhere. This rang bells in terms of my car's starting. It just has to turn one more revolution that I would like before it fires up.. one more than it used to if I am not deceived. This would be why I would like to go a little thinner. Thinking 10W30 as per your thought or even 5W30.

I noted many comparisons between Amsoil and Mobil 1 in the various forums before discovering a youtube clip in which the "A-Team" out performed the "Mobsters" in 5 supposedly defining parameters.. not that you really want to hear that. I do prefer to bat for the small guys if I have the opportunity however and that clip certainly did nothing to harm their case.

Part of my interest in your location was a wayward and stroppy American girlfriend who has recently switched from the starboard coast to your side.. now 126 miles north of you in Santa Rosa.

 

I use 5-30 or 10-30 Full Syn... 5k miles intervals. 40 is too heavy--I have actually notices an RPM drop with 10-40 oil.

 

Very interesting Lev.. a continuation on the "groggy" theme. I take it that because you are referring to the second number you are talking hot running high revs rather than spinning it up from cold. For what it is worth my car feels like it has dropped 400kg of lead weights after I swapped the Fram air filter for a Mann. Thanks to pierce for this advice in respect of the Mann oil filter which I extrapolated to the air filter. I simply could not believe that such a vast incremental increase in power was possible by going back to the manufacturers recommendations.