Oil Change Interval decrease as engine ages?

Just because you read that an aftermarket part is popular does not mean that it is particularly "good"

From what you read online, you'd think that the stock intake is not a "cold air intake"... it is.

Part of it is people buy something and they're excited about it, then later when the novelty wears off, they aren't posting about it.
People claim they "feel" improvement. A new air filter is not going to give you enough of a power increase to "feel"... all it may do is make the intake louder so you THINK it has more power.

K&N, and many other items that are popular, are designed and are good for high performance applications where every bit of power can be the difference between winning and losing. That does not mean that they are the best for long-term durability of your engine.

 

But there is no denying the throttle response improvement is incredible. No dyno run can disprove that.

 

Engine going "BRAAAP" /= improved throttle response

Everyone was claiming the secondary air filter made a difference in throttle response on the 2.7.
Did mine.
My hearing is horrible... deaf in my right ear...
I noticed no difference.
Wife noticed a difference even when I'm not getting on it.

 

I just did my oil change today Mobil 1 and toyota filter, gona stay with this combo every 6k miles for as long as I own this rig.

 

Where are the studies saying performance can increase with a dirty filter?

I noticed in that report that they did say the acceleration performance increased when the filters were clean. To me that says that if you need to use your truck for loads or towing that you'll get better results from not letting your filter be too dirty.

 

In light- and medium-duty applications, the service life is normally defined by accumulated mileage. However, it is very common for over-servicing to occur in these applications due to a lack of understanding of how optimum air filter efficiency is achieved.5,6 The standard recommended service life for an air filter in light- and medium-duty applications, during normal driving conditions, is about 30,000 miles.5–7 It is common, however, for servicing to occur when the filter appears dirty. Engine air filters are designed to actually increase their efficiency by using this initial layer of dust as an added filter layer. Initial filter efficiency is usually approximately 98% but increases to more than 99% by the end of the service life of the filter.7,8 Therefore, changing an air filter before the useful service life is achieved can result in premature engine wear.6,9

Follow the references, that's increased performance trapping dirt. Obviously a clogging filter traps more dirty.

They did show a decrease in performance of, which is to be expected. I'm not saying you won't lose power, but since I don't often exceed 300 rpm I'm not seeing any power loss through a dirty filter. They increased acceleration times 6-11% with grossly clogged filters, too much for someone that wants more power for sure, change that filter but trade some protection.

 

What oil change intervals does everybody use? More specifically, those of you running Mobil 1 synthetics, how long do you stretch it?

Mobil 1 Extended Performance is rated up to 15,000 miles. This seems kind of extreme, but maybe that's just me. What about Mobil 1 Full Synthetic (the regular stuff) or Mobil 1 High Mileage, how many miles would you run on each?

FWIW, I use Purolator Pureone filters.

 

5000 to 7500 miles.

The oil may be good for 25000 or more, but the filtration may not be, and without having an oil sample analyzed, you have no way of knowing.
$25 for used oil analysis?

Not economical.

Oil changes, conventional or synthetic, are one of the most inexpensive things that you can do to your engine that help ensure a long service life.
There are more benefits to a quality synthetic other than extended drain intervals. Extended drain intervals are pushed by the marketing departments to make customers believe that they are getting their money's worth out of the most costly oil.

Mobil-1 claims 15000, Amsoil claims up to 24000, but both say that you should follow manufacturer recommended service intervals while the vehicle is under warranty.