caymandive

iTrader: (2)

I'm sticking with the stock air filter. You really can't go wrong.

Lexmex

I am aware of that, but so far no ill effects.

lobuxracer

iTrader: (2)

Your valve guides don't like it much. They take the brunt of the wear. Since the guides wear faster, you also leakdown faster. Just my experience running open stacks on my street bike for a few years.

Gernby

iTrader: (1)

I could certainly see that being a problem with NO filtration (large debris), but we are talking about a pretty slight reduction in filtration. I feel guilty about saying it, but I'm not particularly concerned about this car going 150K miles, since it is a lease. I know my last car was still making very impressive dyno numbers at 70K when I traded it, and it had an oiled cotton filter almost the whole time.

caymandive

iTrader: (2)

Wow, who else is modding their leased IS350? One of the main reasons I don't lease is the modding and of course mileage penalty's.

Gernby

iTrader: (1)

It should probably be a new thread (if not already), but I don't see any difference between modding a leased car or a purchased car. I restore the car back to stock as much as I can before trading up anyway, and sell the parts separately. Not only does it usually increase the value of the car, but I get some value back from the parts. I'm even planning to put my stock cats back on. Regarding mileage, I'm almost 20% under what I've paid for (I keep a spreadsheet). I may even buy this car at the end of the lease if the resale value is above the residual. Honestly, I don't see how leasing a car is much different from buying a house with a balloon payment.

caymandive

iTrader: (2)

So when you return the car at the end of lease what do they say when they see welded cats back on the car? Just curious. Also how do you see an increase in the value of the car? Sorry I'm just not very familiar with leasing.

Koz

I'd like to see where a K&N is 7% less efficient then a stock filter.

I've used K&N filter in many different vehicles for many years and never had a problem with re-oiling. It's a matter of reading directions.

Hint - Dab filter with a paper towel to remove excess oil.

Koz

lobuxracer

iTrader: (2)

Here you go. Unbiased test results indicate cotton gauze filters do not filter as efficiently as paper filters. They also flow better, which would seem intuitively obvious.

Might want to look at this too. Again, someone believed K&N and thought they could save the company $30k a month in paper filters. It didn't turn out so well.

caymandive

iTrader: (2)

Very good find! Definitely makes sense. More flow the less filtration.

Gernby

iTrader: (1)

In my experience, modded cars don't have good resale value, so I try to make them stock again. This only helps with a leased car because the owner of the lease (in my case, Lexus) would penalize me for the mods. In the case that my car is worth more than the residual, then I would buy it from Lexus, then sell it.

Regarding the welds, I really doubt anyone would notice, but I would just say the original cats went bad, and were replaced.

Gernby

iTrader: (1)

From the link lobuxracer posted, I'm not a bit surprised by Bob's results. However, I think more relavent results would be how the filters perform (flow and filtration) after 10K miles instead of just the 1st 500 miles. It is common knowledge that new filters don't filter as well as dirty filters, but the difference in filter media could change the filtration characteristics as they clog up. Due to allergies, I've made it a common practice to let my 3M home A/C filters get REALLY clogged before changing them. I realize that I'm spending extra dollars on electricity, but I enjoy the cleaner air.

lobuxracer

iTrader: (2)

But if we wait until we've accumulated 10k miles, we've exposed the system to elevated silicates for quite some time, and now you want me to believe this partially clogged filter flows better than a clean paper filter?

I think there's a kind of constant going on here. Quality of filtration and airflow are inversely related. You just have to decide where your personal pain point is. Personally, I don't run K&N in anything with a hotwire MAF. Despite K&N's claims, oil migrates. Even in a vacuum system, oil migration is a huge expensive problem to solve.

A MAF exposed to oil will collect more dirt than one that is not. MAF transfer function is based on clean air, not oily air, or oil and dirt contamination on the sensor. I know it will degrade over time and lose efficiency in the entire system since the MAF is the primary source of data for the fuel system.

I've run K&N filters on a lot of engines for different reasons. At first because I bought the marketing hype and thought it would make more power on my bike. It didn't. It ruined driveability for sure. Later, I thought it would be economical since I could just re-oil the same filter instead of coughing up money for new paper filters. Then I started doing cylinder head work and saw what poor filtration does to valve stems and guides. And I saw dirt build up on the MAFs in my car and others that required cleaning with solvents. This has never happened with a paper filter IME. So, I don't buy their stuff anymore. You can't have your cake and eat it too.

Gernby

iTrader: (1)

I'm not suggesting that WE should all test our own filters after 10K miles of use, I'm just saying that would be valuable information. I'm sure the different filter medias have different flow / filtration characteristics over time. I wouldn't be very surprised if a cotton or foam media would filter AND flow better than a paper media after 1K miles.

Regarding filtration and flow being inversely related, I agree that would be true on equally well designed filters with different medias, but it certainly can't be a "rule". A poorly designed filter of any type could easily have terrible filtration AND flow. Likewise, I believe that a paper filter with LOTS of pleats (surface area) could flow very well.

Koz

1% is nowhere near 7%.

This is the opinion of one of the most respected resident experts on bobistheoilguy (Terry Dyson).

http://theoildrop.server101.com/foru...rue#Post486504

Koz