I wouldn't take offense to what he says. In tuning my prior car, I did a lot of research on various items. There's 2 ways to gain from changing your intake, either reducing pressure drop and/or pulling in air that this getting heated less from the surrounding engine.

The G35 has a CAI, and a pretty good overall intake in my opinion. If you're not reducing pressure drop (assuming there is enought to "correct") then you're not accomplishing anything.

Until someone actually measures the pressure drop in the stock intake compared to whatever modification you're considering, you don't even know if you're making an improvement to something.

 

"pulling in air" the air does not get pulled in, the atmospheric pressure PUSHES the air into the engine to fill the void.

Can't get over the postings about the engine sucking in air, the rings do not seal enough to act like a vac pump!

 

<blockquote><font class="small">In reply to:</font><hr>

Worse are those where the owner tried to clean with the wrong solvent and destroys the MAF by changing its calibration.

<hr></blockquote>

I hate to hijack, but what is the correct solvent for cleaning the MAF?

 

Based on some rough calculations [guessing the diameter of the holes vs solid space from the picture]: My guess is the holey end piece increases resistance by 8-10 inches of water column roughly 0.36 psi @320 CFM resulting at least 2.5-3.0% less air flow than if you removed the end piece or cut out the holes.
Roughly a loss of 6.5-8.0 HP.

Might be even worse as I tend towards conservative calculations.

There is always some disagreement betwen theory and real world conditions as localized flow in a single or group of holes may exceed the sound barrier [Mach number vs Reynolds number] due to shear.

Why not measure the pressure resistance of your set up and let us know the Facts?

Page 2 of the following pdf shows flow and pressure drops for various holes vs CFM down to 1/32"-3.0".
http://www.gastmfg.com/pdf/AirFlowOrifice.pdf

 

I like a quality brake part spray cleaner which evaporates almost instantly and leaves no residue [which might be worse than the oil].

Anything that evaporates quickly is usually very flammable so careful about what gets into plenum. Careful about spraying too close to mechanically stress the sensors.

 

forget about ram air that model in the pic is shmokinnnnnnnnnnnnnnnnnnnnnnnnnnn!!!

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
04.5 G coupe / TB/Willow / 5aT ( I do enough shifting with my bikes) / Premium / Splash guards / Trunk mat // 01 Yamaha R6 / 02 Yamaha R1

 

Guys,

We just did this RAM AIR project for fun just to get a little more air going into the STOCK intake box, because the location of the opening is located behind the bumper, it will NOT attract too much dirt esepecially when the opening already has a prefilter screen, perhaps we will put it on the DYNO next we go, thanks.

Regards,
Unlimited Tuning

 

"pulling in air" the air does not get pulled in, the atmospheric pressure PUSHES the air into the engine to fill the void.

Can't get over the postings about the engine sucking in air, the rings do not seal enough to act like a vac pump!
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BUT... Atmospheric pressure is essentially 0.00 psig (0.00 " water column). So in order for air to flow into the engine, the pressure must be below atmospheric pressure since air flows from hi to low pressure areas. So science says... you must be running with a negative pressure in your plenum in order to get any air in.

Any pressure below the "local" atmospheric pressure is considered "negative suction vacuum" -- uness you are using an "absolute" scale.




2003.5 Sedan 6MT, Brilliant Silver

 

Sucking v blowing - it's all in the eyes of the thing (person) being blown or sucked!

2003.5 DP 5AT Sedan
14.2 @ 97.18
Z-Tube
K&N Drop In & Airbox Mod
10 Wire Hyper-Ground
Crawford Plenum (V4)
UR Crank Pulley
Hotchkis Sways (M/M)
Polk EX-3500 Tweeters/Shock Sensor/H-Liner

 

Hey ozracer01-

I see by your sig that you have an OILED FILTER on your car....you must have a lot of 'character' then.....

'04 G35X Graphite/graphite, NAV, wood, premium

 

can the MAF still get damaged if the filter is oiled properly or if oiled very lightly?

 

WHY VACUUM?

Vacuum exists in the intake manifold as a result of the pumping action of the engine’s pistons and the restriction created by the throttle valve. Were it not for the throttle choking off the flow of air into the engine, there would be little if any vacuum in the intake manifold (like a diesel).

On older carbureted engines, vacuum is needed to pull fuel into the engine. Vacuum siphons fuel through the idle, main metering and power circuits. An engine with a vacuum leak, therefore, will likely be an engine that suffers from the symptoms of lean carburetion such as lean misfire, hesitation, stalling and rough idle. But the same symptoms can also be caused by a clogged catalytic converter or other exhaust restriction, a leaky EGR valve or valve timing problems (all of which reduce intake vacuum).

On most engines, intake vacuum should be steady between 16 and 22 inches. A lower reading usually indicates a vacuum leak, or one of the other problems just mentioned. A reading that gradually drops while the engine is idling almost always points to an exhaust restriction. An oscillating vacuum reading usually indicates a leaky valve or badly worn valve guides.

Fuel injected engines do not require vacuum to siphon fuel into the engine because fuel is sprayed directly into the engine under pressure through the injectors. Even so, vacuum leaks can upset the carefully balanced air/fuel ratio by allowing "unmetered" air to enter the engine. The result is the same kind of driveability symptoms as a vacuum leak on a carbureted engine (lean misfire, hesitation when accelerating, rough idle and possibly even stalling). Common leak points include injector O-rings, intake manifold gaskets, idle air control circuit and the throttle shaft.

Fuel injected engines also rely on intake vacuum to regulate the fuel pressure behind the injectors. Fuel delivery cannot be accurately metered unless a fairly constant pressure differential is maintained. So the fuel pressure regulator diaphragm is connected to a source of intake vacuum. Vacuum working against a spring-loaded diaphragm inside the regulator opens a bypass that shunts fuel back to the tank through a return line. This causes the fuel pressure in the injector rail to rise when engine load increases (and vacuum drops). Thus, the regulator uses vacuum to maintain fuel pressure and the correct air/fuel ratio. A vacuum leak changes the equation by causing a drop in vacuum and a corresponding increase in line pressure.

http://www.aa1car.com/library/vacleak.htm


2004 G35C 6MT Black. Killer.

 

You are confusing the term vacuum with a lower than atmospheric pressure.
Idle and cruise mean nothing they are limited by the throttle plate causing the restriction. Without the restriction rpm would not be stable and increase till the engine explodes or rpm shut off by rev limiter.

WOT is all that counts

Anyway at WOT, there is almost no pressure differential in the plenum............14-15-17 inches WC. 14.2 psi local pressure vs 14.7 psi is a long way from a vacuum. Even idle pressure in the plenum is 5.0 psi.....not a vacuum!
The entire air track from cylinder thru valves up runners into plenum thru throttle body thru MAF thru Air Filter out to the amosphere loses 0.9 psi.................minus 1 psi is a 6.8% decrease in air density so 6.12% is the total loss for all systems out to atmosphere AT WOT ~~ 13.8 psi is the atmosperic pressure that forces air into the cylinder void.

Engineers use 100 KiloPascals to represent 14.7 psi.
Measuring pressure drops in inches of water allows very precise measurement because 4.01 inches of water = 1 kPa (and it takes no less than 27.68 inches of water to equal just 1 psi).

 

Hey Q45TECH,
So how are we supposed to clean our Injen or AEM CAI filter, if we cant reoil them? Are we screwed?

 

If I may butt in... If you re-oil your air filter there are things that you can do to keep the MAF from being harmed.

1. Re-oil VERY LIGHTLY and leave the filter out for a day or so with absorbent paper towels gently stuffed inside of it to help absorb any over spray.
2. Wipe the pleats VERY GENTLY with a paper towel on the outside of the filter once or twice before the filter is reinstalled.
3. Do not over oil.
4. Do not oil too often. Oiling the filter once a year in MOST climates (excluding those who live on a dirt road) is more than good enough.
5. Thoroughly wipe down the filter body before reinstalling.

K&N kit says that you can go 50,000 miles before re-oiling. This is a bit too much for me to feel comfortable living in my climate and road conditions (so I clean it every 10,000 miles or so = once a year). Just keep an eye on your air filter and if you see a lot of dirt build up on it, clean it. You can also run your finger over it to see if it feels the slightest bit oily. If so, you're getting ample filtration (at least as ample as the oiled filter is capable of providing).

You can also remove the air filter in about 30 seconds with a flat head screwdriver. If you're concerned about the oil seeping out and getting on your MAF you can simple do daily checks after you clean and reinstall your air filter. Take the filter off and wipe the inside of the intake with a clean, lint free cloth. If you wipe up ANY OIL just repeat step #2 above and reinstall.

<font color=blue>The above statements are only my take on the issue. If you disagree with anything I typed then you are 100% right!</font color=blue>