Intake air flow problem?

[johned]

I am pretty big on changing my air filter when it needs to be changed and not a moment before. I install one of those little air flow "Filter Minder" gauges to assist me and augment my psychic powers. All has gone well in all these m any years until the Ranger. My Ranger "system" tells me to re[place a brand new filter if I rev over 3000rpm. If I remove the filter the Minder tells me the filter is half clogged at 3000rpm. I know that is a lie as I am holding the filter in my hand that it sayds is clogged and the minder is NOT psychic. Pulling the hose away from the front end of the intake plumbing and removing the filter I get a reduction in vacium that I can only guess is restriction in the intake hose that leads to the cold air intake out in front of the radiator. Even if I replaced the filter with a low restriction upgrade bolt on I would still have the restriction I think the MAF is creating. ???

Now....bottom line: If I were to resolve this intake air restriction would the fix get me any better MPG or of lesser importance....power.

Thanks all,

John

 

[Bird76Mojo]

On ALL of my trucks, I've never replaced the air filter more often than every few years. I always just check how dirty it is when I slap it, and if it seems bad enough, it gets changed. No problems in all of these years.

 

[Ranger850]

On ALL of my trucks, I've never replaced the air filter more often than every few years. I always just check how dirty it is when I slap it, and if it seems bad enough, it gets changed. No problems in all of these years.

same

 

[johned]

same

I most certainly agree with you both. My experience has been the same as yours in that you perceive NO PROBLEM with a filter that just gets smacked to loosen the dust or blown out with a air nozle. Then I got into dirt bikes and single cylinder dirt bikes. They are sensitive in the extreme to little stuff like a plug with not even too many miles or carbon build up or even a mix that is oh so slightly to lean and the filter became a really LARGE issue. All this trivia was born out on dyno tests and Dirt Bike always had a slew of info cause a loss of 5% meant that the guy you waxed last weekend was eating your lunch on the straights. I know, I know , this truck is not a single cylinder 250cc dirt bike. But I only bring that up cause it was in that arenea that I became acutely aware of just how much the little stuff can affect performance. I used to blow out my filter and be proud of my injunity (I am part American Aboriginal) and frugality. Then this Suzi I rode with every weekend installed what was called a GYT kit and soured my day and enriched his. We planned a trip to talcum blow sand and I read where the "FOAM Green Weeny filter was just superb with dust". I installed won of those $20 wonders and won all the future races against that $185 hop up kitted Suzi. A FRIGGEN AIR FILTER! Tests proved that the Weeny was even far superior to the paper element even brand new. BUT!!! The paper stopped waterand the oiled foam did NOT. Ah, the good old days when I had two knees that worked.

Now to put my post into sharper focus: The Minder only identified a problem with intake air flow being less that it could be. The diesel guys are nuts about free flowing their engine air intake and exhaust. Us gas guys should take the hint. My question was, in fact, "how can I free flow my intake"? My Minder says my restriction is greater than a dirty and plugged up filter and that is when the filter is brand new.

Is the intake plumbing ahead of the filter known to be restrictive? I have seen a washable filter that mounts to the MAF sensor and eliminates the stock puiping altogether. As a matter of choice, I would like the cold air source but will give that up for better flow if I must.

I read about guy mounting a different, and possibly less restrictive, MAF. Different injectors seems to be associated with that move.

I am not throwing your advice back at you especially since I was where you are. But you may have a valed point if the improvement in efficiency that a new filter cannot be appriciated in terms of power or efficiency.

So far I have determined that the stock filter must be replaced...air ducts are restrictive...MAF seems to be choking things off a bit. Maybe the MAF "needs" to be a tad restrictive to work. DUNNO!

I apprieciate you assist and advice.

Thanks, John

 

[Bird76Mojo]

This is a Ford Ranger. Not a race truck. Not a race bike. Not even a performance vehicle in any way at all.. Performance gains from any filter aren't really worth worrying about.

I don't blow out my air filters with compressed air. I only slap the filter to see how dirty it is and then replace it if needed.

As for the Filter Minder, it's not something I'd consider using on a Ranger. I don't believe I'd trust it as gospel either.

 

[JohnnyO]

K&N replacement filter in the stock airbox, clean it once a year.

 

[Ranger850]

IDK what a filter minder even is, but MAYBE it's just too sensitive for the setup your using it for. The Filter is more restrictive, meaning smaller "pores" , so less (air and dirt) get through. Where the "foamed oil" filter has larger "pores" to let more ( air AND dirt) through.

 

[alwaysFlOoReD]

I find this topic very interesting. Some of us race Ford Rangers.
OP mentioned he was still getting told of a restriction even with the air filter removed, so its not the filter. That leaves the tubing and the maf. I would suspect the maf too.
Do you know of someone with a flowbench?
Can you post a link of the "filter minder"?

 

[johned]

I find this topic very interesting. Some of us race Ford Rangers.
OP mentioned he was still getting told of a restriction even with the air filter removed, so its not the filter. That leaves the tubing and the maf. I would suspect the maf too.
Do you know of someone with a flowbench?
Can you post a link of the "filter minder"?

I thought I posted the link to filter minder. I'll take care of that when I get back to my computer late tomorrow.
The filter minder is a valuable tool for anyone on any engine. It is a cheap little vacuum gauge was a memory. If it sees vacuum after the filter and the vacuum is enough to meet the threshold then the filter minder just indicates time to change your filter. But if that filter minder says nothing then your filter is Flowing just fine and the filter minder doesn't know how old it is or anything else about it. But the bottom line is, is the thing plugged up or not. On my motorhome pushed by a 440 I saved the price of the filter minder with one filter change. It let me go three times the change interval and I watch my mileage like a hawk and as long as the filter minder said it was okay my miles per gallon were okay. It never told me to change sooner then the regular interval because I didn't spend all the time in heavy dust conditions or blow sand. I really don't think you should turn your nose up with this device and I don't have any stock in the company but it just makes so much sense and they come standard equipment on over the road diesels. And their filters can run three hundred bucks... Gasp. Try filter minder dot-com

 

[8thTon]

You’ve talked about the intake to the airbox and the MAFS which is after the airbox. If you test it with no filter and the airbox open does the result change?

 

[8thTon]

Looked into this a bit more. All tubing and every filter will create some amount of flow restriction, and therefore some pressure drop from atmospheric when and engine tries to pull air through it. This device is simply measuring the pressure drop from atmospheric to a point downstream of the filter. Any further restrictions downstream of wherever the device is connected will be invisible to it. Where was the device connected to the intake?

It appears it is calibrated to somewhere around 20" H2O. Keep in mind however that when you measure intake vacuum you are looking at inches of Hg. 20" H2O is less than 1.5" Hg, so this is a pretty sensitive measurement.

When does the filter restriction affect hp? Well that depends - anything that reduces the volume of air drawn in will reduce max hp, so in theory any restriction limits max hp. However with some carbs it will be much worse. If the carb has a bowl vent direct to atmosphere any filter restriction causes the mixture to get richer. If the bowl vents to downstream of the filter (like in any car from later years of carbs), then the mixture is more constant - but still not as constant as a modern EFI system. Not sure about dirt bike carbs, but any all-position carb is especially sensitive to intake restriction as they don't provide a mixture that is constant with airflow anyway.

That said it must be seeing some pressure drop greater than usual, but I'm not convinced how important that is, or how unusual it is on a vehicle. Especially at other than max hp. The ECU could probably detect this based on air flow, throttle position and rpm, but I don't think any bother with it.

 

[PetroleumJunkie412]

When was the last time you blew the carbon out of your intake track?

Unfiltered PCV and (if your truck has) egr (no idea, won't touch a 4.0) will lead to a plugged intake track, plugged injectors, and a slow death.

Doesnt matter how clean your air filter is if you're dumping crankcase fumes and oil vapors into your engine.

Catch Can - weird (but good) results

So, changed valve cover gaskets recently. Noticed an undue amount of oil in the pcv vac lines coming off the valve covers, which seemed odd to me. New pcv 4000-5000 miles ago; it still seemed to be working fine. Just for poops and laughs, tried an experiment. Ordered a $30 amazon catch can...

www.therangerstation.com

 

[ericbphoto]

I put a filter box from a 4.0l on my 3.0l and modified the tubing from the MAF to the throttle body to reduce restrictions. Kept original MAF. One thing I noticed, was that the 4.0l filter box had a plastic tube on the inlet to the box (between box and radiator support) that seemed restrictive. I removed that so now I have a larger opening into the filter box. I have no performance measurements. So I won't make any claims to power gains. I just measured stuff and tried to make sure nothing replaceable had an opening smaller than the id of my throttle body.

 

[johned]

You’ve talked about the intake to the airbox and the MAFS which is after the airbox. If you test it with no filter and the airbox open does the result change?

Yes it does. The vac does go down and the flow is better. My thinking was that te MAF should be very free flowing but that may be "my wish". It takes all of these restrictions to create the "change Filter" alert. If the filter is removed that reading goes down. I can also detect that the filter box is contributing some restriction. I can measure these restrictions.

 

[johned]

Looked into this a bit more. All tubing and every filter will create some amount of flow restriction, and therefore some pressure drop from atmospheric when and engine tries to pull air through it. This device is simply measuring the pressure drop from atmospheric to a point downstream of the filter. Any further restrictions downstream of wherever the device is connected will be invisible to it. Where was the device connected to the intake?

THE FILTER MINDER IS LOCATED RIGHT AFTER THE MAF. I EXPECT "SOME" RESISTANCE BUT NOT "CHANGE FILTER".

It appears it is calibrated to somewhere around 20" H2O. Keep in mind however that when you measure intake vacuum you are looking at inches of Hg. 20" H2O is less than 1.5" Hg, so this is a pretty sensitive measurement.

YES IT IS SENSITIVE. ANY RFESTRICTION WILL REDUCE POWER AND MPG BUT, AS YOU SAID, MAYBE NOT ALL THAT MUCH.

When does the filter restriction affect hp? Well that depends - anything that reduces the volume of air drawn in will reduce max hp, so in theory any restriction limits max hp. However with some carbs it will be much worse. If the carb has a bowl vent direct to atmosphere any filter restriction causes the mixture to get richer. If the bowl vents to downstream of the filter (like in any car from later years of carbs), then the mixture is more constant - but still not as constant as a modern EFI system. Not sure about dirt bike carbs, but any all-position carb is especially sensitive to intake restriction as they don't provide a mixture that is constant with airflow anyway.



That said it must be seeing some pressure drop greater than usual, but I'm not convinced how important that is, or how unusual it is on a vehicle. Especially at other than max hp. The ECU could probably detect this based on air flow, throttle position and rpm, but I don't think any bother with it.

THE ONLY REASON I AM IN THIS IS TO MAKE SUERE THE ENGINE IS "BEING ALL THAT IT CAN BE". MY LOGIC IS THAT ANY SYSTEM THAT IS RUNNING AT THE "CHANGE FILTER" FLOW NEEDS HELP. MAYBE CAN;T GET THAT HELP FOR A REASONABLE PRICE AND THUS THE CONDITION IS "REALITY".