AEM cold air intake with bypass valve

[Patrick F. Clarin]

Can anyone think of a reason why I wouldn't get a bypass valve when putting
a cold air intake on my '02 WRX? It doesn't lessen the airflow through the
intake does it?

 

[Bryan Lee]

No. It so if water splashes your car wont die.

 

[CompUser]

Can anyone think of a reason why I wouldn't get a bypass valve when putting
a cold air intake on my '02 WRX? It doesn't lessen the airflow through the
intake does it?

You're talking air bypass valve, AKA blow off
valve?

The only "advantage" to adding one is the sound-
effect. It will degrade performance. Check
Cobb's forum, for Gary Sheehan's (pro Subaru
rally driver) comments on atmospheric BOVs.

Stock intake system is considered to be a non-
issue up to 300 HP.

Steve

 

[Patrick F. Clarin]

No I'm talking about the bypass valve so water won't be sucked up through
the cold air intake. If they offer this why would anyone not get it since
it will save your engine?

 

[CBK]

I run an AEM cold air without a bypass. It does slightly degrade the
performance as it is a deviation from the normal dynamic of the pipe. The
horsepower loss from the bypass valve is said to be between 2-5, depending
on the application and placement of the valve. I'm not that piddly, that's
not why I don't use it. My filter terminates about 6-7" off the ground. If I
ever have the car in water that deep +4-5" to submerse the filter
completely.... well... I just wouldn't drive in water that deep. I don't
have a bypass valve because I'm not going to hydrolock the engine. easy as
that. If you want peace of mind and can forsee driving through 7-10" of
water... by all means get one. 3hp is a small sacrifice when compared with
the cost of engine replacement.

 

[CompUser]

No I'm talking about the bypass valve so water won't be sucked up through
the cold air intake. If they offer this why would anyone not get it since
it will save your engine?

Okay, now I'm tracking ya...


....I'd guess the answer would be that people who
put those kinda filters on, and people who think
about *protecting* the engine, are in two
mutually exclusive groups!

Note what that "bypass valve" is doing, when it
functions, too...it's letting in totally
UNfiltered air.

Neither item makes any sense on a WRX intake,
which is pretty well recognized as capable at
anything below 300HP...I lost track of what
wheels you have.

Steve

 

[JaySee]

Okay, now I'm tracking ya...


...I'd guess the answer would be that people who
put those kinda filters on, and people who think
about *protecting* the engine, are in two
mutually exclusive groups!

Note what that "bypass valve" is doing, when it
functions, too...it's letting in totally
UNfiltered air.

Bypass valve is filtered.

 

[Dave]

It has been proven time and again that 99% of WRX's recieve NO gains
whatsoever from a cold air intake, and in fact many people report problems
stemming from them. Mainly this is due to improper MAF mount diameter, and
the big bend right before it causing turbulence.

A CAI is a VERY poor performance investment on a WRX to begin with, as an up
pipe will provide REAL gains in hp and torque, as well as improved spoolup..

Check out these sites,
www.nasioc.com
www.i-club.com

Ask around in there about cold air intake and see what you get. Nasioc has a
VERY knowledgeable userbase (for the most part).