[M2LJ]

All I know is from firsthand experience, I had a 1996 VW Passat VR6 with a Neuspeed P-flow and a K&N air filter on it; and whereas I did "feel" better acceleration and get better gas mileage from the car compared to my wife's nearly identical 95 VW Passat VR6, my car also threw CELs all the time where her's did not! I had to replace the MAF sensor several times (which sits right behind the K&N).

I would have to be a total idiot to run a K&N air filter on my LJ down here in dusty central Texas! All you have to do is look at the filter to realize it doesn't stop small particles from passing through it! The stock airbox and filters I use stop a lot of crap from getting into my engine, and the 4.0 I6 is pretty much bulletproof if you take care of it. Why screw up a good thing for a little temporary gain on an engine that was designed more for torque that acceleration?!?

[Slithering_Joe]

Originally Posted by M2LJ

All I know is from firsthand experience, I had a 1996 VW Passat VR6 with a Neuspeed P-flow and a K&N air filter on it; and whereas I did "feel" better acceleration and get better gas mileage from the car compared to my wife's nearly identical 95 VW Passat VR6...

How does a K&N Filter help with better gas mileage?

[Jerry Bransford]

Originally Posted by M2LJ

All I know is from firsthand experience, I had a 1996 VW Passat VR6 with a Neuspeed P-flow and a K&N air filter on it; and whereas I did "feel" better acceleration and get better gas mileage from the car compared to my wife's nearly identical 95 VW Passat VR6, my car also threw CELs all the time where her's did not!

What you may have failed to notice on many of these K&N threads is this... they CAN help SOME vehicles with performance and fuel economy. Those a K&N can help are those that have restrictive air intakes that were purposely designed to be restrictive for any number of reasons. The Mustang 5.0L is one engine that "wakes up" on the street after installing a free-er flowing air intake. Your VW had a restrictive air intake system from the factory so I don't doubt you felt improvement on your VW.

However, this is a Jeep forum... not a VW forum.

The Jeep TJ was SPECIFICALLY designed to have a completely free breathing air intake. It is not restrictive in the least and this is right from Jeep engineering, not hearsay. So in the TJ's case, a free-er breathing air intake isn't going to help in the least. Since it's not restrictive, making it less restrictive won't help. What a K&N WILL do however is let a lot more dirt and dust into the engine. And to me, that is unacceptable. And since Jeeps are typically driven in dusty offroad environments, a K&N air filter is the very very LAST air filter I would run.

[Deacon]

Any suggestions on another conical or cylindrical filter--in other words one that can be run in the cowl--that will provide a proper level of filtration?

[Robert J. yates]

Originally Posted by TDmaster

So, were you born a cynic, or has only just recently come naturally to you? Yes I read the page, let me be more concise...cai is dyno tested to add horsepower and torque not to mention improved mpg. This is fact not fiction! It is one of the few cost effective simple bolt-ons the average joe can perform. My point is, mopar performance would not sell you something that does not meet it's claims! Where else, praytell, can you spend a two or three c-notes and in about an hour have added 6 to 15 HP and 25 ftlb of torque? That's money well spent in my book.

PT Barnum was right!

[Slithering_Joe]

The most restrictive part of a Jeep TJ, Mustang 5.0L or any other engine is the throttle body. Not sure how a free-flowing intake can help with fuel mileage.

[Bigbob]

Originally Posted by Slithering_Joe

The most restrictive part of a Jeep TJ, Mustang 5.0L or any other engine is the throttle body. Not sure how a free-flowing intake can help with fuel mileage.

Probably can't. Even a bigger throttle body probably won't work. Cold air works. Not much, but in my case 1-2 mpg improvement.

[Unlimited04]

Originally Posted by Slithering_Joe

The most restrictive part of a Jeep TJ, Mustang 5.0L or any other engine is the throttle body. Not sure how a free-flowing intake can help with fuel mileage.

actually on the TJ, at WOT, i believe its the exhaust ports in the head. for the TJ's 0331 head casting, the exhaust port shape was changed to make them more restrictive. they did this to cause the Cat's to heat up quicker for emissions purposes. now any time other than WOT, you're completely right, thats the purpose of the TB - to meter the air coming in

a bigger TB does help a little bit with throttle response , mostly 1/2 to WOT transition when merging and such. I highly doubt theres much HP improvement (2% at 4500rpms maybe?), definitely no mileage improvement....i've been running one for ~2 yrs.

[Slithering_Joe]

You guys are thinking too much. I'm talking about how a high flow filter effects fuel efficiency when there is a partially opened throttle body that restricts the air already during most of your "economic driving."

[M2LJ]

Originally Posted by Jerry Bransford

What you may have failed to notice on many of these K&N threads is this... they CAN help SOME vehicles with performance and fuel economy. Those a K&N can help are those that have restrictive air intakes that were purposely designed to be restrictive for any number of reasons. The Mustang 5.0L is one engine that "wakes up" on the street after installing a free-er flowing air intake. Your VW had a restrictive air intake system from the factory so I don't doubt you felt improvement on your VW.

However, this is a Jeep forum... not a VW forum.

The Jeep TJ was SPECIFICALLY designed to have a completely free breathing air intake. It is not restrictive in the least and this is right from Jeep engineering, not hearsay. So in the TJ's case, a free-er breathing air intake isn't going to help in the least. Since it's not restrictive, making it less restrictive won't help. What a K&N WILL do however is let a lot more dirt and dust into the engine. And to me, that is unacceptable. And since Jeeps are typically driven in dusty offroad environments, a K&N air filter is the very very LAST air filter I would run.

Wow Jerry, your technical expertise has no bounds, does it?

What YOU apparently failed to notice was that was entirely my whole point! The K&K was beneficial on my VW (and yes, I know this isn't a VW forum, thanks for pointing that out ) and most of us realize that it provides no benefits for the 4.0L I6.

But thanks again for repeating the same comment for the umpteenth time, I think we all know by now that the K&N will suck in a lot of dirt and dust into the engine, you've repeated that comment so many times that it should be your signature block. Seriously, do you just like to post the same thing over and over again?!?

[Deacon]

You made a post that extolled the virtues of CAI setups and claimed them as beneficial. To come back after the fact and say duh you obviously weren't saying they're useful on Jeeps everyone knows that blah blah blah, well... If we give you the benefit of the doubt, must assume that you're just a terrible communicator. Otherwise, it's nearly trollish.

[Ridin' Around]

Originally Posted by Firekite

Any suggestions on another conical or cylindrical filter--in other words one that can be run in the cowl--that will provide a proper level of filtration?

Amsoil's EAAU with a pre-filter on it.

[Jerry Bransford]

Originally Posted by M2LJ

Seriously, do you just like to post the same thing over and over again?!?

It never occurred to you that the same questions keep getting asked over and over again?

[TDmaster]

Originally Posted by Slithering_Joe

The most restrictive part of a Jeep TJ, Mustang 5.0L or any other engine is the throttle body. Not sure how a free-flowing intake can help with fuel mileage.

Exactly! Seems that everyone here convinced me that CAI is worthless, so instead, I went with the SDS (Supercharger Drive System) from RIPPMODS...picked up over 100 whp on my 3.8L JK

[Deacon]

Originally Posted by Ridin' Around

Amsoil's EAAU with a pre-filter on it.

Nice. Any idea which one fits? :P