The only reason to stick with "the same" oil is if it's the best available oil in the first place.
A quality synthetic oil (Amsoil, Redline, Castrol Syntec 0W30 - aka GC, Mobil 1 EP - not standard M1, or Valvoline Synpower) is ALWAYS a better choice than conventional oil - especially in an engine like the F20/22.

Otherwise - sticking with the "same oil" simply because it's the one you've been using is one of the worst reasons I can think of.

I have no idea where ideas like that come from - I do however know they are not based in fact or logic. It's not unlike performance appraisals of an oil by the way the car "feels" after the installation of the oil - an absolutely worthless assessment.

Your car may not have any ISSUES at 100k+, but you could have used any oil and said the same thing. How about having a leak-down and compression test done, and then report the results. Those tests would help demonstrate how well or poorly Castrol GTX has performed with respect to wear. Another reasonable measure would be to have your cams and cam bearings inspected. "No Issues" means nothing with respect to the relative wear inside your engine.

To the OP: there is no problem switching to a quality synthetic oil - no matter how many miles are on the car.

 

Avoid frequent switching between one oil type and/or brand to another.
The reason for this is every manufacturer uses proprietary chemistry in their oils - and while every manufacturer will typically claim their products are "compatible" with other oils (conventional or synthetic), detergent packages from one oil to another may have minor interactions that may not be beneficial and actually shorten the life of an oil - especially if you consistently change from one oil to another. It's nearly impossible for all manufacturers to test their oils against every other oil available.

When I change from one oil to another, I typically follow that swap with what I call a quick change, in that I run the initial change only half a change interval before I change it again. This ensures that all the old oil is out of the system and minimizes any possible interaction.

As stated before, there's no problem with changing from one oil to another - however, don't make it a continuous process throughout the life of the car.

 

you can switch from synth. to conv. oil as often as you want. It wont hurt anything. If your car starts to have problems its not because of the oil. conventional oils are known to have better lubrication traits but break down quick. synthetic oils are known to last a long time but the lubrication traits dont. the choice is yours really. If you get it changed at a honda dealership it wont matter if its a AP1 or AP2 they are using honda conventional oil.

 

I have no problem switching brands as long as the switch involves a complete drain and refill. For the reasons you mentioned, ad packs are propritary and maybe not compatible between brands. Switch to whatever you like as often as you like but also agree that at some point everyone should be able to make up their mind and stick with their favorite lube whatever it may be.

 

The key is to do some reasonable, logical and scientifically-based research ahead of time and determine what oil is best for the application.
I specifically use Amsoil ATM 10W30 because it is the best 10W30 currently on the market.
Too many people treat oil like wine, as if there's an influence in "taste". Trust me - the S2000 is a machine (without taste) that's built to exacting clearances and designed to run a 10W30 motor oil... I choose to use the best oil that falls in that category - simple as that. When a better 10W30 comes along, I'll switch.

Switching oil brands and/or types all the time in order to save a few bucks here or $10 there is like tripping over dollars to pick up pennies and is counterproductive - find a top quality synthetic oil in the right viscosity range and then stick with it until another oil comes along that is verifiably, significantly better.
I named a few brands that I would use (in order of preference based on several factors) and would only change if cost or quality drastically shifted, and then I would re-evaluate before I chose the replacement oil.

Long of the short is that you should not stick with an oil simply because that's what you've been running... but also don't constantly change oil types or brands unless you have a logical reason to do so. Pick a logical quality (proven) choice and stick with it until you can make a logical argument to change to another brand/type.

 

Yes on one point... and definitely NO on the other.

Yes, in that conventional oils do break down faster than QUALITY synthetic oils.
NO, in that a quality synthetic oil provides better wear protection than conventional oils - especially in high shear/high temperature conditions - ie. AP1 at 9000+ RPM under load.

 

Reading all of these posts about not mixing oils kind of concerns me. I had about 3 qts of mobil1 but I heard it wasn't a true synthetic... So I bought 2 qts of mobil1 ep and mixed them together because I didn't want to throw out the other mobil1.. Hopfully it's ok to mix those 2... No problems yet. Next oil change, I will be using straight amsoil 10w30.

 

You'll be fine - just don't run the oil for an extended drain interval. Change it out at around 3000 miles or so and you'll have no problems.

 

all oil r compatible with each other.. jus that its not good to be frequently switching between different brands of oil.

synthetic is always good... way better than reguler oil.

 

i agree with slipstream, his opinion is why i switched to amsoil, i still burn through oil, but it seems to hold up great, plus ap1's are known to do that, you will be just fine, stick to a syn, that stands by its product