Aftermarket air filters revisited

[Arizona Vipers]

Just looked through some old threads, mixed opinions on the K&N. Has anyone dyno'd it back to back several times vs the stock filter?
The reason I'm asking is we are getting 19hp and 12tq more without the filter in. This is back to back, several runs with an extremely experienced tuner.

[serpent]

I run the greenfilter: https://greenfilter.com/store/7149

I believe sneaky snakes runs this for his 9L Extreme as well.

[Arizona Vipers]

I run the greenfilter: https://greenfilter.com/store/7149

I believe sneaky snakes runs this for his 9L Extreme as well.

Thanks! has anyone done back to back dyno on it? Do you have to oil it?

[Jack B]

On my car when it was stock, removing the filter caused it to go into limp mode

[Simms]

On my car when it was stock, removing the filter caused it to go into limp mode

I've heard this with numerous owners.

[Dan Cragin]

The Gen 4-5 airbox and filter are very good. The production filter has very deep pleats and much more surface area than a K&N. We never saw a power increase.
I did a before and after test on Jerry Mahl's 2008 Viper (owner of K&N) with the complete FIPK system back in the day and it made the same power as stock.

On the Gen 1-2 Vipers we see a 10hp gain with K&N over stock.

[Meteoro]

limp mode on mine too without the filter

[cashcorn]

I replaced my stock air filter with a K&N panel filter in the original air box. No problems & looks so much better not to see the white oem filter hanging down while blocking air from coming in..

[Arizona Vipers]

The Gen 4-5 airbox and filter are very good. The production filter has very deep pleats and much more surface area than a K&N. We never saw a power increase.
I did a before and after test on Jerry Mahl's 2008 Viper (owner of K&N) with the complete FIPK system back in the day and it made the same power as stock.

On the Gen 1-2 Vipers we see a 10hp gain with K&N over stock.

Great info, thanks!

[Steve M]

How much longer are you going to be on the dyno? Long enough to get your hands on one so you can get us some solid data on OEM vs. K&N (or similar) vs. no air filter?

It could be that the 9L is just more sensitive to the changes because it requires more air in.

[Arizona Vipers]

How much longer are you going to be on the dyno? Long enough to get your hands on one so you can get us some solid data on OEM vs. K&N (or similar) vs. no air filter?

It could be that the 9L is just more sensitive to the changes because it requires more air in.

Yeah this 100%

[ViperGeorge]

I've wondered whether over time the oil from filters like K&N make its way on to sensors like AIT sensors or MAP/MAF. If it does then performance may degrade over time as oil builds up.

[Steve M]

I've wondered whether over time the oil from filters like K&N make its way on to sensors like AIT sensors or MAP/MAF. If it does then performance may degrade over time as oil builds up.

I think you have to assume it will, and just make cleaning the MAF sensors a regular part of your maintenance if you run an oiled filter. Obviously it depends on how heavily it is oiled, and since that involves a human at some point, that makes it a little more difficult to tell.

For the Gen 4/5 cars, you'd only have to worry about the combined MAF/IAT sensors (one in each intake tube). The IAT sensor probably wouldn't matter nearly as much as the little wires that make the MAF sensors work. If those get coated in a light film of oil, it'll cause potential issues with your fueling.

The MAP sensor is tucked in the back passenger side corner of the intake manifold. That thing already gets pelted with any excess oil from the PCV system, so a little more from an oiled air filter probably won't matter.

[ViperGeorge]

I think you have to assume it will, and just make cleaning the MAF sensors a regular part of your maintenance if you run an oiled filter. Obviously it depends on how heavily it is oiled, and since that involves a human at some point, that makes it a little more difficult to tell.

For the Gen 4/5 cars, you'd only have to worry about the combined MAF/IAT sensors (one in each intake tube). The IAT sensor probably wouldn't matter nearly as much as the little wires that make the MAF sensors work. If those get coated in a light film of oil, it'll cause potential issues with your fueling.

The MAP sensor is tucked in the back passenger side corner of the intake manifold. That thing already gets pelted with any excess oil from the PCV system, so a little more from an oiled air filter probably won't matter.

Should our MAP sensors be periodically removed and cleaned even without having an oiled filter? Is that easy to do? Should we have spares just in case?

[Steve M]

Should our MAP sensors be periodically removed and cleaned even without having an oiled filter? Is that easy to do? Should we have spares just in case?

Removing the MAP sensor from the intake manifold is really easy to do. If I'm remembering correctly, it is held in place with a single screw.

I swapped my original one over from my Gen 4 intake manifold to the Gen 5 intake manifold when I did that swap many years ago. It looked perfect. I've not touched it since.

I wouldn't worry about it. I'm not 100% sure, but I'd guess it is a shared part with many, many other Chrysler products, so it should be easy to source in the unlikely event you'd ever need one.

[Arizona Vipers]

I've decided to keep using the stock filter. Even if an oiled one added 5hp, it's just not worth it having to oil etc. And then wonder if you oiled it propertly... Buttom line, more flow= more debris getting into motor anyway...

[ViperGeorge]

I've decided to keep using the stock filter. Even if an oiled one added 5hp, it's just not worth it having to oil etc. And then wonder if you oiled it propertly... Buttom line, more flow= more debris getting into motor anyway...

I think that is a smart choice. I remember speaking to an engineer at SRT about filters. He said "Don't you think that if we could have add 10 or so virtually free HP by changing the air filter we would have done that? The stock air filter is very, very efficient."

[Arizona Vipers]

I think that is a smart choice. I remember speaking to an engineer at SRT about filters. He said "Don't you think that if we could have add 10 or so virtually free HP by changing the air filter we would have done that? The stock air filter is very, very efficient."

Yep... I got all excited seeing that 19hp 12tq laying on the table. LOL! Was 804whp and 728wtq vs 785hp 716tq
If I was a drag racer I'd take it out that's a no brainer. But not for hours on the track.... Maybe next time I'm 1/10th behind 1st place I'll take it out. lmao

[Whiskey]

Yep... I got all excited seeing that 19hp 12tq laying on the table. LOL! Was 804whp and 728wtq vs 785hp 716tq
If I was a drag racer I'd take it out that's a no brainer. But not for hours on the track.... Maybe next time I'm 1/10th behind 1st place I'll take it out. lmao

804rwhp NA is positively bonkers. How huge is that cam lol? I'm sure with a well designed intake setup it can have your 19rwhp and filtering too. PM me and I will give you some ideas to try. I can't bank roll the idea but if you can bring it to market I'm sure you would sell a few of them.

[ViperGeorge]

I have wrapped insulation around my IAT sensors and I use DSE's airbox heat shield. I also insulated the bottom of the airbox. My headers are Swain coated. The reason I say this is that the ECM pulls timing as IATs and coolant temps rise. I read somewhere that it starts pulling timing when IATs exceed something like 80 degrees. Given this we are all losing power as the engine heats up or the air it takes in heats up.

If someone could develop a way of better controlling IATs we would gain power when the engine is warm. There was a company I saw that built water cooling jackets/coils for the intake. Maybe something like that or some better way of insulating the IAT sensors would make more sense than a different air filter. Jack did have a device that fooled the ECM to think IATs were cooler than they really were but he discovered a knock problem and pulled the plug so to speak.

This looks interesting but maybe complicated to install on a Viper.

https://www.designengineering.com/air-intake/

[Arizona Vipers]

I have wrapped insulation around my IAT sensors and I use DSE's airbox heat shield. I also insulated the bottom of the airbox. My headers are Swain coated. The reason I say this is that the ECM pulls timing as IATs and coolant temps rise. I read somewhere that it starts pulling timing when IATs exceed something like 80 degrees. Given this we are all losing power as the engine heats up or the air it takes in heats up.

If someone could develop a way of better controlling IATs we would gain power when the engine is warm. There was a company I saw that built water cooling jackets/coils for the intake. Maybe something like that or some better way of insulating the IAT sensors would make more sense than a different air filter. Jack did have a device that fooled the ECM to think IATs were cooler than they really were but he discovered a knock problem and pulled the plug so to speak.

This looks interesting but maybe complicated to install on a Viper.

https://www.designengineering.com/air-intake/

The car also pulls timing at crazy low coolant temps, like 200, so the car is never really making full power.

[Old School]

I have wrapped insulation around my IAT sensors and I use DSE's airbox heat shield. I also insulated the bottom of the airbox. My headers are Swain coated. The reason I say this is that the ECM pulls timing as IATs and coolant temps rise. I read somewhere that it starts pulling timing when IATs exceed something like 80 degrees. Given this we are all losing power as the engine heats up or the air it takes in heats up.

If someone could develop a way of better controlling IATs we would gain power when the engine is warm. There was a company I saw that built water cooling jackets/coils for the intake. Maybe something like that or some better way of insulating the IAT sensors would make more sense than a different air filter. Jack did have a device that fooled the ECM to think IATs were cooler than they really were but he discovered a knock problem and pulled the plug so to speak.

This looks interesting but maybe complicated to install on a Viper.

https://www.designengineering.com/air-intake/

I know the Corvette boys relocate their IAT forward, less susceptible to heat soak.

[ViperGeorge]

I know the Corvette boys relocate their IAT forward, less susceptible to heat soak.

The problem with that or even insulating the hell out of the airbox is that it won't help if ambient air itself is hot. The ECM starts pulling timing at ridiculously low temps, something like 80 degrees. The DEI thing, if one of our great vendors (yo Doug) could adapt it the Viper would also cool the air to below ambient. They claim up to a 50 degree reduction. With a 50 degree reduction in the intake air charge the ECM would likely never be pulling timing due to intake air temps.

[Steve M]

Up to 50° reduction at super low flow rates, maybe.

At flow rates closer to what you'd see with an engine running at WOT, I have my doubts. That's a big change in air temperature for what little time I'd guess the air would actually interact with that portion of the intake on its way into the engine. I'd have to make some assumptions and do some math before I was positive though, and I don't have time at the moment.

What you don't want to do is under-report the air temps coming in to the engine. I think it is pretty well understood that the IAT sensors report accurately, it's just that they get blasted with hot air; that really only happens at low speeds though. Once you get up to speed, the IATs are very close to ambient.

Timing does get pulled starting anywhere over 77°F for IATs. I'd have to go back and check when timing starts getting pulled for elevated coolant temps. Not great for making power, but it does at least keep your engine in one piece.

When drag racing, I zero both of those tables out. It's what keeps my car consistent in the quarter mile regardless of the ambient temps. But I also know that I'm assuming some amount of risk. Those tables are not zeroed out for my street tune, and I'd consider going even more conservative on a road course, especially if it was going to be hot out. That's mostly because I'm running a fair amount more timing across the board over the stock tune, and I'm also on the stock Gen 4 hypereutectic pistons. Hopefully my luck continues to hold - it will be an expensive mistake if that day ever comes.

[Pappy]

I have had a slightly different experience with the IATs. I monitor IAT closely, and like others have said, timing is pulled at fairly low temps - 80 degrees or so is about right. Here in the hot desert, my car will start out fairly close to ambient, and while driving the first time will build to 12-15 degrees above, regardless of speed. The IAT does not decrease with increased speed. After I shut the motor down, the IAT sensor appears to heat soak and when I restart the car, the IATs will be 25+ degrees above ambient and never recover much to a lower ambient to displayed IAT differential. I have seen IATs as much as 40 degrees over ambient! This is without shielding on the air box or IAT sensors. Since the IAT sensor is basically integral to the MAF sensor, it would be difficult to move it upstream into the incoming air, but that would help. I think heat soak of the sensor is causing artificially high readings, and that is a horsepower killer. I realize heat shielding would help some, but I doubt it would do much to prevent heat soak from a hot engine after it is shut down (I do open the hood while the car sits). On a typical hot, but not extreme day, I have run the first early morning session feeling pretty strong. After that, the car is such a slug that I generally just park it.

Pappy