2003 4.0 5spd Dyno run Before/After K&N

[4x4junkie]

I understand what your saying about resetting the computer, but part of the software sniffs the exhaust and reads air intake temp through its own sensors you place on the vehicle(you can see the wires/sniffer in the pic). For all of the runs the rich-lean ratio was bout the same, no more than a tenth or two off. If it was getting more air and not realizing this it would show lean on the computer. And yeah the truck was fully up to temp-20 mile ride there. And just for fun cause we had it right there we cleaned the maf with some BS in a can that is supposed to not only clean it but "improve rwhp"-and SURPRISE-absolutely no difference. The poor truck got at least 10 runs that morning.

This is very true, the PCM is always in a constant state of "learning". There should be no need to reset it.

I would however say that the truck should be driven around several miles for it to readapt after swapping the intake.

FWIW, many years ago I swapped a K&N filter into my Ranger (just a filter in the stock box, not a whole intake). It seemed like there was a tiny infinitesimal power increase afterward, but I couldn't say whether it was because of the filter type, or if it was simply because I went from a dirty filter to a clean one. The K&N caused a whole bunch of other issues with the MAF & O2 sensors, the IAC and some other stuff though. I wound up taking it out and putting a paper filter back in. This time I couldn't tell any difference between them in terms of power.

 

[Chance]

It seemed like there was a tiny infinitesimal power increase afterward,

I believe that's called the placebo effect

 

[tony314]

When I used to run K&N's in my 97 ranger. I was always getting codes tripped. I removed it and went back to stock and the codes never returned.

 

[bigcountry]

a guy from FRF said when he say this that the pcm is in an "open loop". this is what he says. I have to say that dyno test was not accurate. Like many said he did not reset the ECU and it was not setup like he was driving. There was no air flowing into the front of the truck like he was going down the road

Reset the ECU and have a Fan blowing across the front of the truck and lets see the numbers.

(ECU is in open loop during a run.)

 

[Mutant Pony]

I'm not surprised at this test at all. I'm also sure that resetting the computer isn't going to help.
The K&N systems do add performance to certain vehicles. Just not all. That is somewhere in the fineprint. I have seen the improvements.
No matter what you do it is not going to show an improvement on the Ranger.
What I find really interesting is the replies that tell of trouble codes caused by the K&N. If the K&N where doing absolutly nothing for the engine, there would be no trouble codes caused by it. In those particular applications a fuel curve adjustment WOULD show an improvement somewhere.

 

[Bob Ayers]

I do agree that you need to do the runs by resetting the PCM. The newer PCM's take into account ALL parameters coming from the MAF and the O2 sensors.

At WOT, it's running open loop, and the O2 sensors aren't being used!


The K&N intake screws up the airflow across the MAF sensor is the problem. The OEM intake / paper filter isn't the limiting factor for airflow into the engine. For example, if the engine pulls 500CFM, and the OEM intake will flow 800CFM, and the K&N will flow 1000CFM (along with some dirt & oil) you will still get the 500CFM the engine is pulling with the K&N....

 

[Bob Ayers]

No, but the PCM does "learn" after each reset. That is why it is good to reset the PCM after each engine/transmission mod by unhooking the negative battery cable for about 5-10 minutes.

If you unhook the negative battery cable, and touch it to the positive battery terminal for a second, this will discharge the decoupling capacitors in the unswitched 12V circuit in the PCM, so you don't have to wait. Or, disconnect the negative battery cable with the headlights on, and that will do the same thing. All you have to do is provide a current path for the decoupling capacitors to discharge.

 

[Ranger Sport Honduras]

At WOT, it's running open loop, and the O2 sensors aren't being used!


The K&N intake screws up the airflow across the MAF sensor is the problem. The OEM intake / paper filter isn't the limiting factor for airflow into the engine. For example, if the engine pulls 500CFM, and the OEM intake will flow 800CFM, and the K&N will flow 1000CFM (along with some dirt & oil) you will still get the 500CFM the engine is pulling with the K&N....

basically no matter how big intake u put or the best filter its still gonna pull the same amount of air
learned that on my first days around here
and Bob Ayers told me

 

[caser876]

Alright, i'll try to hit all of what i read-We did have a large fan blowing on the front of the truck, the dyno guys know how to set it up. I prolly made some confusion but when i said rich/lean ratio i was referring to the A/F ratio-its the same thing. Being that the ratio was correct resetting the computer would not make a difference-this is what you all are saying that it needs to relearn itself, it did it, automagically. After 4 pulls and no change in curve with the intake on, driving it wouldn't do anything. like was said before, SOME vehicles will see a gain over the stock airbox, obviously not a ranger. And just for shits and giggles, i believe i know where a "tornado" is laying around at one of my uncles shops. I might put the truck back on the dyno in the spring just confirm my beliefs that it don't do crap, and to have solid proof for when the idiots think it really works, but the road salt really isn't good for the dyno.

 

[Toms01PSD]

When you ran the dyno test, was the sticker on the truck? The intake parts themselves are just for looks; it's the sticker that adds the HP.

 

[Original_Ranger84]

Well technically you should do what the others are saying... and reset it but i don't care... This is awesome!

I wonder though... what about a drop in filter?

What about the gains of the kit you got after an exhaust is added?

 

[eric17mx]

I wouldnt put in a tornado last time i seen a pic of one and its paper thin metal and rivets are just waiting to be sucked into your nice motor!