Observations after removing the hydrocarbon filter
- Thread starter LV4R
- Start date
chayos00
New member
I'm with the same agreement as you! I believe it's due to the large surface area of the filter it allows much more air to be brought in versus if we had a smaller filter just allowed just enough air in.
MikesToy
Banned
I think it only applies to the V8's. I think i gained 1hp. LOL
martini
New member
After having my filter out for over a month I've seen a maybe a 1 MPG increase. I always go to the same gas station, and drive extremely close to identical routes each week which keep the variables down. I've been tracking my MPG for about 6 months now, all MPG tracking has been done by hand too. Also no increase in noise either inside or outside even with the heat/AC and radio off.
Last edited:
wetwilly17
New member
not too long ago i purchased an 05 sport edition and i'm glad i found this site. i was looking for some free 'mods' for my engine and found this thread. i will be removing my hydrocarbon filter tomorrow. i don't think it will give noticeable power but i figure why not...i may gain a horsepower or two...
anyways, i see a lot of people on here wondering and claiming that you can get better gas mileage from removing it. i see confusion all the time about intake products and mods that will supposedly give you better gas mileage.
we can all agree that the hydrocarbon filter is restrictive to some degree (maybe insignificant but maybe not). we can all agree that because of the restriction there is a pressure drop across the filter. any pressure drops in the intake system means less air molecules into the combustion chamber during the intake stroke which means less power. so most people figure that by reducing the pressure drop in an intake (such as by removing the hydrocarbon filter) that you would in turn gain fuel economy (maybe an insignificant amount or maybe significant).
this idea is completely wrong. remember, the engine power and the amount of fuel that is combusted is regulated by the throttle / butterfly valve. the throttle intentionally creates a pressure drop. so any reduction in pressure drop through the intake system caused by removing the hydrocarbon filter would mean that your right foot would simply be slightly less on the gas pedal for any particular speed. the free-er flowing the intake, the more closed the throttle will be. there is no impact to gas mileage.
anyways, i see a lot of people on here wondering and claiming that you can get better gas mileage from removing it. i see confusion all the time about intake products and mods that will supposedly give you better gas mileage.
we can all agree that the hydrocarbon filter is restrictive to some degree (maybe insignificant but maybe not). we can all agree that because of the restriction there is a pressure drop across the filter. any pressure drops in the intake system means less air molecules into the combustion chamber during the intake stroke which means less power. so most people figure that by reducing the pressure drop in an intake (such as by removing the hydrocarbon filter) that you would in turn gain fuel economy (maybe an insignificant amount or maybe significant).
this idea is completely wrong. remember, the engine power and the amount of fuel that is combusted is regulated by the throttle / butterfly valve. the throttle intentionally creates a pressure drop. so any reduction in pressure drop through the intake system caused by removing the hydrocarbon filter would mean that your right foot would simply be slightly less on the gas pedal for any particular speed. the free-er flowing the intake, the more closed the throttle will be. there is no impact to gas mileage.
Actually, the fuel is regulated by the PCM within a closed loop (feedback) system consisting of the throttle position, O2 sensors, engine load, air temp, etc. (after warm up)
But putting more air into the engine doesn't equate to better mileage...In fact, it should be the opposite. To keep the proper air/fuel ratio the PCM will add more fuel if it senses more oxygen via the closed loop feedback. More air could equate to more power though.
I've heard that the internal combustion engine is nothing more than an air pump. So, by 'freeing up the airflow', it doesn't have to work as hard to move the air in (or out...free flowing exhaust)...thereby allowing the engine to work more 'efficiently'. I believe that's where the 'improved' mileage would come from with everything else being equal.
But putting more air into the engine doesn't equate to better mileage...In fact, it should be the opposite. To keep the proper air/fuel ratio the PCM will add more fuel if it senses more oxygen via the closed loop feedback. More air could equate to more power though.
I've heard that the internal combustion engine is nothing more than an air pump. So, by 'freeing up the airflow', it doesn't have to work as hard to move the air in (or out...free flowing exhaust)...thereby allowing the engine to work more 'efficiently'. I believe that's where the 'improved' mileage would come from with everything else being equal.
SolRayz
New member
Well I pulled mine last weekend and I'm showing about 2-3 mpg more than before, whether my meter/indicator is telling the truth or not, is another story. After the next fill up I plan on doing some calculations.
btw at highway speed (60mph) I was hitting 23-34 mpg?!?!! Is this even possible?
btw at highway speed (60mph) I was hitting 23-34 mpg?!?!! Is this even possible?
MikesToy
Banned
I hit 31mpg @ 105mph. w00t! :reddance:
OrdnanceMarine
New member
I suspect this conclusion is the most correct. The throttle is what (by design) governs restriction of air to gasoline engines. Until you get to the point that the throttle is no longer the bottleneck (maybe as low as 30% throttle at low RPMs where the engine can't digest much air) everything else on the induction system doesn't come in to play. We have modern fueling systems that can maintain a given air/fuel ratio under all conditions to thank for this. It's only when you need more power than the engine can provide at a given RPM and airflow which either results in the ECU enriching the mixture (many engines drop the air/fuel ratio from the standard ~14.7:1 to something in the ~13:1 or even richer at high loads for best power and reduced knock at the expense of fuel efficiency) or shifting the transmission and increasing the RPM, that a flow restriction such as the filter negatively affects MPG.
I may pull this filter tomorrow just to see what I get on longer trips to see what real world results I see.
OrdnanceMarine
New member
After doing this I can't notice any difference in power and I have yet to see any change in fuel economy even closely tracking it via my ScanGaugeII on the same highway at the same speeds under the same conditions.
bigwebb83
New member
I kind of figured this might be the case. I'm guessing that others who think they reallized some gain (many of which were extreme at 2-3 mpg) were paying more attention than normal to the onboard readout and thus were driving easier than normal. As stated before, the intake really isn't a bottle neck and even if you can get more/colder air into the combustion chamber the computer will still look for the target a/f ratio and hit it by adding MORE fuel.
Trem720
New member
So last week I had my oil changed and air filter checked, and was told I needed a new air filter. I decided to put a drop in K &N filter in rather than the OEM paper filter. I was told that by removing the HCF filter, I would gain a little more flow as well. So I went ahead and did this, and since then, my gas mileage (according to the onboard computer) has gone WAY down. I would consistently get 17-18 around town and 22-23 on the highway (with 32.8"tires and a 3" lift). Now the on-board comp is reading 12.5-12.9. No matter how aggressive I drove before that, I never saw my computer below 16.8. What do you guys recommend? Should I try resetting the ECU? I can't imagine how removing the HCF and adding a new K &N would cause this.
Thanks.
Thanks.
RoarFunner
New member
Often times, K&N filters are way over-oiled. This can cause an oily film to build up on the MAF sensor which can affect its readings, causing it to miscalculate AF ratio. In some cases, the damage to the MAF is permanent (or the damage caused by careless cleaning). Now, this may not be your issue at all, but it's something to look at.
Also consider if you may have used fuel from a different brand or station than usual.
If all else fails, you could throw a paper filter back in and see if it really makes a difference.
shuly
New member
I would agree with this....if the oil builds up on the sensor it can cause this. Removing the HCF filter will make oil build up easier too. Get some MAF cleaner from your local auto parts store. It is really easy...just don't directly touch the wires. They are protected by a plastic housing so it isn't too big a deal...just be aware of it.
When I switched to the K&N filter (still have the HCF in place) my mpg went up by about 0.3-.4mpg...not much but every little bit helps with a trail rig.
Trem720
New member
Thanks. I would assume that you disconnect the MAF sensor and remove it from the throttle body before cleaning? Also, what is the best method for cleaning, Q-tips? What should I be avoiding and what should I be cleaning on the sensor? Sorry for the bombardment of questions, but I have yet to mess around with a MAF yet.
