K&n
08-23-07, 06:35 PM
#3
Moderator
Air or Oil?
Investigate fully on air filter. I am not saying it is bad, but there are consequences.
Salim
Investigate fully on air filter. I am not saying it is bad, but there are consequences.
Salim
08-23-07, 06:48 PM
#4
I used to put them on everything, but having the car out of commission while the filter dried was a pain. I know you could get an extra paper one to pop in while it dries, but again a pain. I found I would not clean it as often since it was such a hassle.
The factory filers are cheap enough and fit perfect. IMO
Speaking from experience.
08-23-07, 10:53 PM
#7
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08-24-07, 06:41 AM
#8
Super Moderator
My advice is that if you are going to use the K&N air filter, speaking from experience, wash off the oil and then just reoil lightly the front side facing the air flow in order to avoid the MAF sensor becoming coated with oil and causing a P0171 error.
08-24-07, 09:15 AM
#9
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Join Date: Apr 2007
Location: TX
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I have a Fram Airhog filter that I was planning on using. It is another reusable, oil coated filter. Can I assume I might have this problem also? Anybody use an Airhog?
08-24-07, 11:09 AM
#10
Super Moderator
To give you another idea of the fact that the MAF can get dirty, as you know I don't use an air filter (something I don't recommend), but every week before I run at the track, I carefully clean off the red diode and two wires, and I can tell you the red diode is caked in exhaust and whatever other contaminants haunt the lovely air of Mexico City.
Most MAF/air filter oil issues I have heard of down here crop up in the warmer months of the year.
08-25-07, 06:18 AM
#12
Super Moderator
08-25-07, 08:52 AM
#14
Super Moderator
Good question. 
Gas mileage...power...even emissions.
Gas mileage. The gasoline sold here by Pemex, even Premium 92 octane, is not conducive to burning. After a few years of using an air filter, I realized after taking it off one day (a K&N by the way) my MPG was no longer in the 10 to 12 mpg range on a daily commute, but started to hit the 12 to 14 range,mbut gradually teetered up to where it is now in the 15 to 16 mpg range. I have known in my time in Mexico City a few other RX300 owners and all reported under 15 mpg. To burn better, the gas needs as much air (really oxygen) as it can get, and having bad gas and 23% less oxygen than at sea level (probably more given the pollution) doesn't help.
Emissions I used to get a higher hydrocarbon (unburnt gas) or HC count when my RX300 was stock, at idle, over 100 on some occasions (which is not good for Mexico City) when I tested it down at an exhaust shop back in 2004 that I now frequent a lot. No precats, a high flow cat, Torquemaster plugs, some larger piping, etc., and now I get down into the teens on HC counts, that will pass you in California, and now 50 HC passes you (it is voluntary for me here) in Mexico City, is used to be 100 HC before July 1st of this year.
Power: I can't give a precise measurement in hp, but the intake modifications in my RX are a SIGNIFICANT factor in 1/4 mile times, especially the lower air intake. Now, there was a brief period of time back in mid-2004 when I had a stock RX300 and nothing more than a K&N filter, and I never got into the 18 second range, always stuck between 19.2 and 19.6 as I mentioned on my website. Of course, it took some modifications to get to the 17.931 record I have today. However, a few experiments I did at the track with and without the K&N air filter revealed a .1 second difference (about a car length) improvement without the filter. I recently tested this concept on a Mazda CX7, and that revealed a .15 second result, but that was using a stock, not a K&N air filter.
Now, yeah there is a risk. Something enters the air path could choke the engine or scratch the cylinder walls, perhaps choke the IACV valve... I use Restore oil additive for cylinder walls, about a week before changing out my oil. As with the other things, never had an issue. About the only goofy incident that happened to me was back in Dec. 2005 when I blew an ignition coil a few hours after using an excess amount of carb cleaner cleaning out my intake.
I would just call it kind of a strange and unique situation. Not too long ago I was talking to someone in Bolivia who had an RX300 down there (a lot of them come out of Brazil or from the U.S.) and they also mentioned to me thay had to stop using an air filter as the gas costs were killing him.
Gas mileage...power...even emissions.
Gas mileage. The gasoline sold here by Pemex, even Premium 92 octane, is not conducive to burning. After a few years of using an air filter, I realized after taking it off one day (a K&N by the way) my MPG was no longer in the 10 to 12 mpg range on a daily commute, but started to hit the 12 to 14 range,mbut gradually teetered up to where it is now in the 15 to 16 mpg range. I have known in my time in Mexico City a few other RX300 owners and all reported under 15 mpg. To burn better, the gas needs as much air (really oxygen) as it can get, and having bad gas and 23% less oxygen than at sea level (probably more given the pollution) doesn't help.
Emissions I used to get a higher hydrocarbon (unburnt gas) or HC count when my RX300 was stock, at idle, over 100 on some occasions (which is not good for Mexico City) when I tested it down at an exhaust shop back in 2004 that I now frequent a lot. No precats, a high flow cat, Torquemaster plugs, some larger piping, etc., and now I get down into the teens on HC counts, that will pass you in California, and now 50 HC passes you (it is voluntary for me here) in Mexico City, is used to be 100 HC before July 1st of this year.
Power: I can't give a precise measurement in hp, but the intake modifications in my RX are a SIGNIFICANT factor in 1/4 mile times, especially the lower air intake. Now, there was a brief period of time back in mid-2004 when I had a stock RX300 and nothing more than a K&N filter, and I never got into the 18 second range, always stuck between 19.2 and 19.6 as I mentioned on my website. Of course, it took some modifications to get to the 17.931 record I have today. However, a few experiments I did at the track with and without the K&N air filter revealed a .1 second difference (about a car length) improvement without the filter. I recently tested this concept on a Mazda CX7, and that revealed a .15 second result, but that was using a stock, not a K&N air filter.
Now, yeah there is a risk. Something enters the air path could choke the engine or scratch the cylinder walls, perhaps choke the IACV valve... I use Restore oil additive for cylinder walls, about a week before changing out my oil. As with the other things, never had an issue. About the only goofy incident that happened to me was back in Dec. 2005 when I blew an ignition coil a few hours after using an excess amount of carb cleaner cleaning out my intake.
I would just call it kind of a strange and unique situation. Not too long ago I was talking to someone in Bolivia who had an RX300 down there (a lot of them come out of Brazil or from the U.S.) and they also mentioned to me thay had to stop using an air filter as the gas costs were killing him.