A 215 ci [3.5 liter] engine only can injest half its volime [107.5 ci] every rpm.
At the highest flow rate above 6,000 rpm......one would be lucky to get 310-320 CFM. [215 grams per second] at 35 F ambient [200 grams per second at 100F]

None of the available Filter Systems offer any significant resistance to such a small air flow, as the convoluted square inch area [pleat numbers and depth] when spread out is very large. True cotton with lots of holes and minimal thickness is slightly less restrictive than paper, but if you'll measure the square foot area you will see the paper compensates with more surface area.

Air filter type and design is not significant considering that from worst flowing to best flowing is only 1.0" of water column which is 1/28 of the total restriction.

A MAF has 7 times the restriction of the best air filter element.

All the engineering in the world in front of TB [new air pipes, no sound deading, shape changes, etc] cannot change the total resistance [to air flow into cylinders] by much more than 1-1.5%.........even no air filter at all.

A temperature change in the air of 11F will change the air density by 1%! In theory this will change the engine power 1%.

The critical problem is that the MAF was calibrated with the oem design in place, to provide the ecu with the most accurate signal of TRUE air flow. Changes can affect the MAF calibration and this directly controls the amount of fuel injected.

From a power standpoint this can be good or bad and may vary in 100 rpm increments. What was good at 70F may be bad at 80F [because besides the air density the MAF has an integrated air temp sensor] the converse will probably be true also at different air pressures.

At WOT and above the torque peak rpm the mixture is set protectively rich [richer than 12.5 AF] to cool the combustion charge...........this trades a few HP for engine reliability in the long run.

What every system provides the coolest air to the MAF is best. Much more important than if an air filter flows 0.05% better.

A big plastic pipe sticking straight up thru the hood 8 feet above the road surface would provide cooler air than some low under bumper pipe.
Look at diesel tractors and study where they get their air.

Obviously no one wants this ugly but efficient contraption, so the factory compromised injesting cooler air as high as possible.

 

I am glad I sold my Poop Charger, I also felt I lost alot of low end torque and it was REALLY annoying at stop and go traffic, it felt like the car was struggling to accelerate from stop. I changed back to stock airbox and with the stock accordian piece and everything feels back to normal.

After the P-C install, I did reset the ECU by 3 methods, taking the positive and negative and touching them together, the pedal method, and 24 hour reset method, I gave my car 2 weeks to learn after each reset, still no help, in my experience, just stick with the factory setup.

 

Factual MAF temp readings do not show a temp benefit for the height of the oem inlet vs system's in the bumper. Readings of +9/+10 from ambiant are what the oem system does. My system, inlets all of 10" off the ground and averages +7/+9 from ambiant, again actual MAF temp readings. I am not the only one to have found this out, their are other's that have factual MAF temp data on the same subject. If the myth of hot pavement is true, it effect both intake height's equally.

The popcharger averages +20 to ambiant at speed, when the car slow's down and stops, MAF temps spike dramatically and remain high until suffecient speed is built (45+). If one can build a simple surround for the popcharger(side sheild won't do), one can dramatically lower at speed intake temps, you should be able to come within 1 degree or so of oem. However, in town your still against it.

I don't doubt that the popcharger can or does make power, but aren't most dyno's open hood affairs? With the hood open, MAF temp readings will not be very different between oem and the popcharger, if at all.

"All that's necessary for the forces of evil to win in the world is for enough good men to do nothing.”
Edmund Burke

G35 6mt

 

Why are dynos open hood you don't drive that way?

Anyone [a dyno tech/shop] insisting on an open hood is asking for serious errors.

The shop should have a fan that creates 150 mph wind and the dyno must be loaded with an eddy brake to simulate wind resistance............otherwise measurements are near worthless [10% errors at minimum] compared to real world performance.
I didn't say factory was optimum just the best they could fit underhood.
Cut some holes in hood and raise the intake......maybe a nice big ugly scoop, or suck the coolish ACed air from the passenger compartment [wear ear protection] and crack a rear window. Spray a 10-15 HP shot of N2O for cooling into air box.......prior to filter.

Lots of choices.

 

Not sure how one feels a 0.033 second improvement from 50 > 80 mph when a timed quarter mile only gets 0.10 second better.........if that? You can pretty well equally divide 0> 50; 50>80, & 80>100 mph.

The more you spend the more HP it must create, doesn't always work, recently as the factory HP Marketing Race is in full swing--------- squeezing the numbers for publication.

The Marketing department is relentlessly pushing for 299.50000000000000000000000000000000000000001 HP so they can say 300+. Find me an engine any engine, tweek the hell out of it, who cares if the rest are no where close just find that 299.5 one so I can send the copy to the publisher.

I once suggested that the dyno cell inlet air be juiced with Nitrous 5% by some marketing types hanging around outside near the vent with big briefcases..........watch out for a leaking liquid oxygen tanker truck parked near the dyno lab.........every 1% more oxygen in the air adds almost 5% [4.7%] to an engines HP.

 

Q45tech,

"Air filter type and design is not significant considering that from worst flowing to best flowing is only 1.0" of water column which is 1/28 of the total restriction. "

Boy you sure got that right. I just measured the psig difference between the Stillen and Stock intake @ 5.5K RPM. I made the measurement from the oil vapor return behind the MAF and silencer.

Stillen Delta P= 0.236" water as measured from the intake duct. ( 0.0087 PSID)
Stock Delta P = 0.394" water as measured from the intake duct. (0.0146 PSID)

Tony


Tony

2004 G35 6MT Blk/Blk Sedan Stillen Air, Stillen Exhaust

 

Hey_Ya, can the popcharger be used with the stillen airbox together? Does this force more direct airflow through the filter?