Aftermarket air filters

LibertyCRD · **Posted:** Tue Feb 28, 2006 10:46 am

A diesel engine draws in more air than a comparable gasoline engine because of the turbo charger among other things. Therefore aftermarket filters such as the K&N are an even worse idea for diesels than they are for gas engines. Would you guys say this is generally a true statement? Or are there actually some higher flowing filters on the market that are diesel safe??

omniphil · **Posted:** Tue Feb 28, 2006 11:11 am

LibertyCRD wrote:

A diesel engine draws in more air than a comparable gasoline engine because of the turbo charger among other things. Therefore aftermarket filters such as the K&N are an even worse idea for diesels than they are for gas engines. Would you guys say this is generally a true statement? Or are there actually some higher flowing filters on the market that are diesel safe??

In my experience, when using a k&n style filter on a turbo engine (gas) gains are ususually minimal to none because the turbo provides the need airflow. Non Turbo engines generally benifit more from better flowing air filters.

The same goes for changing the entire intake like with a cold air intake system that replaces the factory stuff with a nice smooth higher flowing pipe. Gains on turbo motors are alot less than non turbo motors.

The other piece of the puzzle is the engine rpm. high flow air filters/intakes make their power at higher rpms when the restriction on air flow is multiplied. This is why you see high revving honda motors get gains up near 10hp with a air intake system, but if you look at the power curve on a dyno chart, lower in the rpm range the power is usually none.

With a diesel the rpms are very low most of the time, probably another reason why the k&n air filters dont all that much. (speculation)

And like most k&n stlye filters, dirt into the motor is increased. Which if you change the oil every 3000 miles isn't all that bad. It just dosent seem worth it on a low reving turbo engine with very high oil change interval to gain maybe 1-2hp.

I had purchased a mopar performance air filter for our Liberty V6, we actually picked up 1mpg with it. But with the new 2006 CRD we're using the stock paper filter. You just need to change it often to keep it fresh.

My mopar performance filter is for sale if anyone wants it

oldnavy · **Posted:** Tue Feb 28, 2006 11:31 am

Go to this site for ISO 5011 Duramax air filter testing the way mfg's have there OEM filters tested and designed. It's a real eye opener.

If that is not enough for you do an oil test before and after installing a K&N filter, that will put the fear of god in you for sure when you see the amount of dirt in the oil jump 400 to 500 times what would be considered a normal limit. I have seen some of those on VW diesels, talk about guys ripping out K&N's and installing OEM fast. However people every day fall for the sale hype.

retmil46 · **Posted:** Tue Feb 28, 2006 1:35 pm

Speaking of which, does anyone know of a website/company that will let you order AC Delco air filters on line?

AC Delco website simply gave me a list of local retailers, all Advance Auto. When I called the local Advance stores, they said they would order the oil filters, but for air filters I had to order them from the AC Delco website! :roll:

When i told them that the AC Delco website said to order them thru Advance Auto, the response i got was "We don't order the air filters in this area" CLICK (sound of Advance hanging up phone on me)! :evil:

Simple mod you can try to see if more airflow helps this engine any - remove the inlet hose to the air filter housing. The stock air intake sucks in air from just behind the grille, and picks up anything that gets sucked into the grille. At 8000 miles, the floor of the air filter housing was covered with pine needles, bugs, and dirt. You could also see where it had been sucking in water during a hard rain. Half the filter surface area wasn't just dirty, but BLACK with caked dirt and whatever. The air intake takes a snake path from the grille to the inlet hose, and where it goes past the headlight, it narrows down to the point that you can't even stick your hand into it.

RTStabler51 · **Posted:** Tue Feb 28, 2006 2:48 pm

oldnavy wrote:

Go to this site for ISO 5011 Duramax air filter testing the way mfg's have there OEM filters tested and designed. It's a real eye opener.

If that is not enough for you do an oil test before and after installing a K&N filter, that will put the fear of god in you for sure when you see the amount of dirt in the oil jump 400 to 500 times what would be considered a normal limit. I have seen some of those on VW diesels, talk about guys ripping out K&N's and installing OEM fast. However people every day fall for the sale hype.

I ran a KN on my Gen II Lightning with a K&N and my filtertration was great. The last oil sample I did said it was the cleanest 5.4 they had seen that month.

tired_old_dave · **Joined:** Wed Feb 22, 2006 3:45 pm **Posts:** 79

I only registered her to thank jdrecard and retmil46. I have now posted many more times than I wanted to. If lost kj'ers visit edmunds please tell me here and I will enjoy only reading your posts. My tranny delay appears to have been a "spurrious event"
Post 3277 at edmunds liberty diesel is my aero install for which I thank retmil46 and would like it critiqued.
Posts 4142 & 4143 reflect my cheap attempt at cool air after farmdiesel or somebody said only mods would be air in and exhaust out. I did see the flat amsoil donaldson filter at the dallas rv show but don't like the idea of not cleaning with soap like an aem.

LibertyCRD · **Posted:** Tue Feb 28, 2006 9:26 pm

retmil46 wrote:

Simple mod you can try to see if more airflow helps this engine any - remove the inlet hose to the air filter housing. The stock air intake sucks in air from just behind the grille, and picks up anything that gets sucked into the grille. At 8000 miles, the floor of the air filter housing was covered with pine needles, bugs, and dirt. You could also see where it had been sucking in water during a hard rain. Half the filter surface area wasn't just dirty, but BLACK with caked dirt and whatever. The air intake takes a snake path from the grille to the inlet hose, and where it goes past the headlight, it narrows down to the point that you can't even stick your hand into it.

I've been running mine like this for quite some time. I seemed to pick up 1 mpg, so I did the same thing to my wife's 3.7L. I don't see how it would hurt anything.

oldnavy · **Posted:** Wed Mar 01, 2006 11:16 am

RTStabler51 wrote:

I ran a KN on my Gen II Lightning with a K&N and my filtertration was great. The last oil sample I did said it was the cleanest 5.4 they had seen that month.

I can only tell you what I have seen on about 1/2 dozen turbodiesels, not NA gassers. It may be more to do with the max influx of air by a turbo, all I can say is I saw the lab reports and it was shocking. And as you can see the testing done on the diesel Duramax was bruttle to the K&N filter.

Also guys the reason the comparrison is done with AC Delco filters in the ISO testing of the Duramax is that is OEM filter brand name for GM, and they are saying stick with OEM filters, whether Ford brand for Fords, MOPAR brand for Jeep, or VW brand for VW on your vehicle. He is not saying the AC filter is the best filter made for all vehicles, just for GM. The auto mfg sets the max standard for the amount of filtering for the engine, then the filter mfg makes it to that standard. An aftermarket filter such as Fram or Wix may not want to spend the extra $1 to have the same quality of filtering for that auto and also the same filter may be used across several vehicle mfgssuch as Ford, GM and Chrysler where standards for mfg good be different for the different engines

RTStabler51 · **Posted:** Wed Mar 01, 2006 11:57 am

oldnavy wrote:

RTStabler51 wrote:

I ran a KN on my Gen II Lightning with a K&N and my filtertration was great. The last oil sample I did said it was the cleanest 5.4 they had seen that month.

I can only tell you what I have seen on about 1/2 dozen turbodiesels, not NA gassers. It may be more to do with the max influx of air by a turbo, all I can say is I saw the lab reports and it was shocking. And as you can see the testing done on the diesel Duramax was bruttle to the K&N filter.

Then Gen II Lightning is a Supercharged 5.4L, FWIW....

oldnavy · **Posted:** Wed Mar 01, 2006 1:27 pm

RTStabler51 wrote:

Then Gen II Lightning is a Supercharged 5.4L, FWIW....

Not worth anything to me, I'm not a Ford guy.

If you are happy with product and vehicle then truck on, I am just telling you what I know and have seen.

tired_old_dave · **Joined:** Wed Feb 22, 2006 3:45 pm **Posts:** 79

One last comment. Sometime when everything is hot, put your hand in front of your naked air box and you will feel hot air from the fan being sucked into the airbox. I think something is needed to prevent that airflow if what people say is correct about shrouding cold air filters.

oldnavy · **Posted:** Wed Mar 01, 2006 1:55 pm

tired_old_dave wrote:

One last comment. Sometime when everything is hot, put your hand in front of your naked air box and you will feel hot air from the fan being sucked into the airbox. I think something is needed to prevent that airflow if what people say is correct about shrouding cold air filters.

That's probably why they routed the intake out in front of the radiator, trying to pull cooler air to offset the only place they could put the air box under the hood without going to a lot of extra expense.

How about a Ram Air setup on the hood, that would help with getting cooler air into the engine.

greiswig · **Posted:** Wed Mar 01, 2006 2:01 pm

...well, hopefully. I've been talking to a vendor near me who is VERY aware of the filtration issues that K&N has in independent testing, but knows well that the CRD could use less restriction on both intake and exhaust. He is currently working on a deal with a manufacturer who makes a filter that should flow 30-50% more than stock, but which does not lose the filtration capability of an OEM paper filter. He's been prodding around under the hood of my truck a bit, and I suspect that he'll be making a new box for it, too.

He is an exceptionally careful, thorough guy, so I look forward to what he comes up with. It might pay in the long run to save your $$ for a while as he designs this, and just replace your filter with a paper one if needed.

Best,

omniphil · **Posted:** Wed Mar 01, 2006 2:17 pm

greiswig wrote:

...well, hopefully. I've been talking to a vendor near me who is VERY aware of the filtration issues that K&N has in independent testing, but knows well that the CRD could use less restriction on both intake and exhaust. He is currently working on a deal with a manufacturer who makes a filter that should flow 30-50% more than stock, but which does not lose the filtration capability of an OEM paper filter. He's been prodding around under the hood of my truck a bit, and I suspect that he'll be making a new box for it, too.

He is an exceptionally careful, thorough guy, so I look forward to what he comes up with. It might pay in the long run to save your $$ for a while as he designs this, and just replace your filter with a paper one if needed.

Best,

Keep in ming that just because an air filter flows more air that has no bearing on weather or not the engine will make any more power. especially when talking about a turbo charged motor. The turbo sits in the way and will negate most of any gains of a high flow air filter.

My suggestion for the folks that have access to a dyno is this. (something I did on my car to verify any HP claims) Run the Jeep on a dyno with the stock setup. then remove the entire aixbox assembly and intake tube. Run it again, if you see any difference then you can start to put pieces back and see where the restriction is. If you see no gains then nothing you do to the airbox/filter will help at all. This will cost you about $50-75 or so and will provide the needed info.

Most people assume the stock airbox/intake is restrictive, and it may very well be, but remember, if you add more airflow than the motor can use its not going to do anything.

My guess is because of the very low rpm range of this motor that you will see no gains what so ever.. But I am wrong alot

Our club has a dyno day coming up in April I think, I will certainly run this test on the jeep if anyone wants...

greiswig · **Posted:** Wed Mar 01, 2006 3:11 pm

omniphil wrote:

Keep in ming that just because an air filter flows more air that has no bearing on weather or not the engine will make any more power. especially when talking about a turbo charged motor. The turbo sits in the way and will negate most of any gains of a high flow air filter.

My suggestion for the folks that have access to a dyno is this. (something I did on my car to verify any HP claims) Run the Jeep on a dyno with the stock setup. then remove the entire aixbox assembly and intake tube. Run it again, if you see any difference then you can start to put pieces back and see where the restriction is. If you see no gains then nothing you do to the airbox/filter will help at all. This will cost you about $50-75 or so and will provide the needed info.

Most people assume the stock airbox/intake is restrictive, and it may very well be, but remember, if you add more airflow than the motor can use its not going to do anything.

My guess is because of the very low rpm range of this motor that you will see no gains what so ever.. But I am wrong alot

Our club has a dyno day coming up in April I think, I will certainly run this test on the jeep if anyone wants...

I think that there are some potential benefits for a turbocharged engine, particularly if the vendor is treating the system as a whole, including the exhaust. If nothing else, a higher flow air filter will have greater longevity before clogging to the point of impact on performance. If the same vendor is going to try to ensure that cool air alone is brought in, that also should be good. While not as large a difference as the intercooler may make, it can't hurt.

I'd definitely be interested in hearing the results of any dyno test you do!

oldnavy · **Posted:** Wed Mar 01, 2006 3:50 pm

The K&N and OEM air filter's were tested on some TDI's about 4 years ago at a shop that had Dyno and the testing was done before and after installing a K&N on several VW TDI's, 1.8T, and a 2.0 non turbo and a another non turbo V6 gasser that I don't remember the brand. The TDI's and 1.8T (turbo 1.8L gas) only gained about .5% hp increase over a 3 run average, and the NA gassers had about 15 or 20% average increase if I remember correctly.

Any good turbo tech or engineer will tell you that a turbo will always pull the required air or suffer a loss of power. When you unrestricted a turbo on the exhaust side you allow for easier and faster spool up, reducing EGT's and general strain on the engine. The hp increase in not enough to even mention, but the ability of the engine to reach power band quicker helps with pulling loads or general hot roding.

If your filter clogs up enough the turbo will work harder to draw air and down goes economy and power. If the turbo is stronger then the filter, and I have never seen one that wasn't, it will ingest filter. There were several TDI's that sucked the filters into engine when intake was clogged with snow or allowed to become clogged with debris. In my years around diesels I have seen one (Cat or DD don't remember) and heard of others suck intake gaskets trying to get air when the air intake was shut off to diesel generators. The one I saw was because a turbo seal failed allowing the engine to accelerate to max rpm and a piece of aluminum was placed over the intake, causing the turbo to suck out part of the intake gaskets and allowing the engine to self destruct.

valkraider · **Posted:** Thu Mar 02, 2006 2:33 pm

oldnavy wrote:

Any good turbo tech or engineer will tell you that a turbo will always pull the required air or suffer a loss of power. When you unrestricted a turbo on the exhaust side you allow for easier and faster spool up, reducing EGT's and general strain on the engine. The hp increase in not enough to even mention, but the ability of the engine to reach power band quicker helps with pulling loads or general hot roding.

I don't think anyone ever claimed otherwise... But the issue at hand is whether or not any of us, or the CRD, actually operate under those parameters.

In real world use are our turbos suffering from air starvation? How can we measure that?

I think I would personally be inclined to err on the side of more filtration - since I have no problems or issues with the performance of the CRD, even when towing through the mountains or accelerating in traffic. But that is just me....

oldnavy · **Posted:** Thu Mar 02, 2006 8:35 pm

valkraider wrote:

oldnavy wrote:

Any good turbo tech or engineer will tell you that a turbo will always pull the required air or suffer a loss of power. When you unrestricted a turbo on the exhaust side you allow for easier and faster spool up, reducing EGT's and general strain on the engine. The hp increase in not enough to even mention, but the ability of the engine to reach power band quicker helps with pulling loads or general hot roding.

I don't think anyone ever claimed otherwise... But the issue at hand is whether or not any of us, or the CRD, actually operate under those parameters.

In real world use are our turbos suffering from air starvation? How can we measure that?

I think I would personally be inclined to err on the side of more filtration - since I have no problems or issues with the performance of the CRD, even when towing through the mountains or accelerating in traffic. But that is just me....

I doubt the CRD suffers from air starvation, just pull out the air filter and see if there is a difference.

BlackLibertyCRD · **Posted:** Sat Mar 04, 2006 10:10 pm

Today I found out that the Green Air Filter that I removed from my Magnum RT that I turned in for the CRD indeed fits. http://www.greenfilterusa.com/ I put it in to be sure of more air flow for when I added a V-Force Muffler http://www.flopro.com/VForce.htm also today. The Green filter is supposed to filter down to 5 microns seems to be good to me. I don't know how much better the paper filter could be if better than 5 microns.

Reggie · **Posted:** Sun Mar 05, 2006 10:54 am

oldnavy wrote:

valkraider wrote:

oldnavy wrote:

Any good turbo tech or engineer will tell you that a turbo will always pull the required air or suffer a loss of power. When you unrestricted a turbo on the exhaust side you allow for easier and faster spool up, reducing EGT's and general strain on the engine. The hp increase in not enough to even mention, but the ability of the engine to reach power band quicker helps with pulling loads or general hot roding.

I don't think anyone ever claimed otherwise... But the issue at hand is whether or not any of us, or the CRD, actually operate under those parameters.

In real world use are our turbos suffering from air starvation? How can we measure that?

I think I would personally be inclined to err on the side of more filtration - since I have no problems or issues with the performance of the CRD, even when towing through the mountains or accelerating in traffic. But that is just me....

I doubt the CRD suffers from air starvation, just pull out the air filter and see if there is a difference.

In a lot of cases the air filter box and inlet plumbing is the restriction. I'm not saying that's the case with our CRDs but it is something to think about.

Aftermarket air filters

Who is online