The cold air intake debate
03-07-2004, 10:57 PM
#76
Registered User
iTrader: (12)
Join Date: Nov 2002
Location: Reno, NV
Posts: 18,369
Car Info: 1993/2000/2001 GF4 mostly red
Nah. Basically, by leaving the factory filter box/MAF housing in place, the filter will ensure that the air flows properly over the MAF. Changing things upstream of that can increase or decrease efficiency, but will be read by the sensor as the ECU expects it.
03-08-2004, 04:18 AM
#77
Registered User
iTrader: (2)
Join Date: Nov 2002
Location: Lawrence, Kansas
Posts: 1,644
Car Info: 19' Impreza Sport Manual / 99 Miata / 13' OB
From this thread here:
http://www.subaruforester.com/viewto...r=asc&start=15
http://www.subaruforester.com/viewto...r=asc&start=15
Cobb validated Peaty's perspective on CAI - not necessary - just open up the stock airbox and save yourself some money. He said they have dyno results to prove it. They dyno'd three aftermarket CAI's (didn't say which) and they do not flow as consistently as the stock airbox, thereby causing MAF to behave erratic through the curve. This might be okay for some, he said, but with the XT, Cobb's goal is mega hp increase without any glitches, flat spots, huffs, etc. (that weren't their before the mod's, of course).
03-08-2004, 06:50 AM
#78
VIP Member
Join Date: Feb 2003
Location: 12.9 / 105+
Posts: 488
Car Info: black my03 5mt wrx s/w
Originally posted by jimr
Last summer I pulled my stock resonator out from the front fender (at the suggestion of the author AG Bell, "Forced Induction Performance Tuning"....which shows some charts listing pressure drop the resonator caused on a Legacy B4 and a GC8 WRX, very interesting reading too), and bolted up a 3" diameter (at neck) alloy air horn from Summit in the fender well and dumping directly in stock air box. The next morning I made a run from the Fairfax area up Highway 1 north to Mendocino (CA for our out of state members) and the car DID run like a scalded cat! Once 3-3500 came up on the tach, the car lurched forward like it was being uncaged. I was kind of surprised.
[snip]
Any thoughts?
Last summer I pulled my stock resonator out from the front fender (at the suggestion of the author AG Bell, "Forced Induction Performance Tuning"....which shows some charts listing pressure drop the resonator caused on a Legacy B4 and a GC8 WRX, very interesting reading too), and bolted up a 3" diameter (at neck) alloy air horn from Summit in the fender well and dumping directly in stock air box. The next morning I made a run from the Fairfax area up Highway 1 north to Mendocino (CA for our out of state members) and the car DID run like a scalded cat! Once 3-3500 came up on the tach, the car lurched forward like it was being uncaged. I was kind of surprised.
[snip]
Any thoughts?
it works VERY well and i see no effective difference between this setup and any aftermarket CAI. the benefit of this setup is a) cost... it was like 20 bucks for the velo stack, and b) stock airbox + stock maf tube = accurate maf readings. been running this setup for 15k miles, problem free.
hth
ken
03-08-2004, 12:39 PM
#79
Registered User
iTrader: (6)
Join Date: Jan 2003
Location: Sunny LA West Side
Posts: 363
Car Info: Silver 2002 WRX Sedan
There was data posted on one of the forums that showed that the factory intake draws cold air from the high-pressure area in front of the car creating a "ram air" effect at speed. So, to get the best of both worlds I decided to do the following:
1) I removed the rubber weather stripping from the leading edge of the hood. I does not do much anyway and there are no problems wth any sealing or rattling with it removed.
2) Then I got a resonator eliminator elbow from Chris at Stealth Composites. (You can contact Chris at stealthcomposites@hotmail.com). This is the best flowing / least restrictive resonator bypass I have found. The piece is hand-made and the quality is excellent. The inside walls are as smooth as glass and transitions are smooth and fluid. They were also available in Carbon Fiber, but I got the FG cause I am a cheapskate.
This setup is ideal to me. It combines the best of all worlds. It results in higher-than-stock flow while keeping the true functionality of the cold air intake and sucking the air from the high pressure region in front of the car. It is also not as noisy as a straight resonator delete. It works well and I like it, plus the dealer cant really tell its there when you paint the ends black!
1) I removed the rubber weather stripping from the leading edge of the hood. I does not do much anyway and there are no problems wth any sealing or rattling with it removed.
2) Then I got a resonator eliminator elbow from Chris at Stealth Composites. (You can contact Chris at stealthcomposites@hotmail.com). This is the best flowing / least restrictive resonator bypass I have found. The piece is hand-made and the quality is excellent. The inside walls are as smooth as glass and transitions are smooth and fluid. They were also available in Carbon Fiber, but I got the FG cause I am a cheapskate.
This setup is ideal to me. It combines the best of all worlds. It results in higher-than-stock flow while keeping the true functionality of the cold air intake and sucking the air from the high pressure region in front of the car. It is also not as noisy as a straight resonator delete. It works well and I like it, plus the dealer cant really tell its there when you paint the ends black!
03-08-2004, 12:49 PM
#81
Registered User
iTrader: (1)
Join Date: Nov 2002
Location: LA, 91355
Posts: 352
Car Info: '03 WRX WRB
lol.. available in carbon fiber
a cf peice that you couldn't see unless you pull your fender off
.
I just hacked the snorkle off my stock one and plugged the hole with a peice of plastic and some jb weld. also drilled a little hole at the lowest point to let water out
a cf peice that you couldn't see unless you pull your fender off
.I just hacked the snorkle off my stock one and plugged the hole with a peice of plastic and some jb weld. also drilled a little hole at the lowest point to let water out
03-08-2004, 07:41 PM
#82
Registered User
iTrader: (6)
Join Date: Jan 2003
Location: Sunny LA West Side
Posts: 363
Car Info: Silver 2002 WRX Sedan
True, you can't see cf in there, thats why I opted for the fg myself, but you know there are some CF ****** out there who'd have their toilet seat made from CF! You know what I mean!
(No offence to anyone!)
As far as hacking the stock piece, I thought of that too, its a "free mod" but I am a perfectionist. When you hack the box you get rid of the resonator box, but you leave the convaluted stock connector elbow in place which creates a bit of tubulence (read pressure drop / flow restriction) in the air path. The piece I got is much better flowing because the air path is straight and turbulence free. The guy who designed it worked on the B2 bomber, so he knows a thing or two about airflow.
Hey, it works for me, thats all I'm saying. Just trying to help with alternative approaches.
Cheers!
(No offence to anyone!)As far as hacking the stock piece, I thought of that too, its a "free mod" but I am a perfectionist. When you hack the box you get rid of the resonator box, but you leave the convaluted stock connector elbow in place which creates a bit of tubulence (read pressure drop / flow restriction) in the air path. The piece I got is much better flowing because the air path is straight and turbulence free. The guy who designed it worked on the B2 bomber, so he knows a thing or two about airflow.
Hey, it works for me, thats all I'm saying. Just trying to help with alternative approaches.
Cheers!
03-15-2004, 06:49 PM
#83
Guest
Posts: n/a
cai = all show no go
its been said a hundred times on this thread but i feel the need to say it again. CAI does jack for performance. however, they look good under the hood and sound good, so if you want something that will spice up the engine bay or somethin, buy yourself a CAI. otherwise, save up for something more useful, like a bigger IC or FMIC, which TRULY cools the air.
03-16-2004, 05:27 PM
#84
Guest
Posts: n/a
well, I have to use a aftermarket intake..... big a$$ front mount intercooler smiling at you. as far as MAF, Stock size is what 2 1/2? just make sure that any intake you get has the same size tubing. Im tired of talking about it. its all matters on your budget and what you need to do. like i said, i need a aftermarket intake. but i spent $50. got the tube from ebay, and bought a weapon r filter from nopi.. if you have a choice between the two what would you chose?
LESS COOLER AIR or MUCH MORE WARMER AIR
LESS COOLER AIR or MUCH MORE WARMER AIR
03-29-2004, 03:38 AM
#85
Registered User
iTrader: (38)
Join Date: Oct 2003
Location: rightBehindYou, HI
Posts: 7,783
Car Info: 1973 Huevo Ranchero
alright i don't get all this "mumble jumble" stuff 
all i know is that i have a blitz in my wagon and my sti ... i love the sound... thats my bottom line.... i really don't care at this point... its just sounds good and i kinda like the often "fluttter" i hear from the CAI...
all i know is that i have a blitz in my wagon and my sti ... i love the sound... thats my bottom line.... i really don't care at this point... its just sounds good and i kinda like the often "fluttter" i hear from the CAI...
03-31-2004, 06:26 PM
#86
Guest
Posts: n/a
When we run the Turbo Porsches at the track (road course) on a cool morning, we always develop more horsepower. It is all about the delta T, or change in temperature. If your CAI is truly drawing from a significantly cooler/denser air you will improve performance, how much is dependant on the delta. Improved airflow is a benefit in it's own right. Remember an engine is nothing more than a fancy air pump.
03-31-2004, 07:09 PM
#87
Registered User
iTrader: (12)
Join Date: Nov 2002
Location: Reno, NV
Posts: 18,369
Car Info: 1993/2000/2001 GF4 mostly red
Once again, with Subaru MAF-based engine management, it's not the temperature that is the problem, it's the change in the way the air flowing over the MAF creates its signal. Disrupting the factory setup is almost never a positive change. Furthermore, the factory setup already draws "cold" air from in front of the radiator. All you can do with an aftermarket intake is get closer to the engine and radiator wash.
04-23-2004, 07:25 AM
#89
Registered User
iTrader: (12)
Join Date: Nov 2002
Location: Reno, NV
Posts: 18,369
Car Info: 1993/2000/2001 GF4 mostly red
Originally posted by BAN SUVS
Once again, with Subaru MAF-based engine management, it's not the temperature that is the problem, it's the change in the way the air flowing over the MAF creates its signal. Disrupting the factory setup is almost never a positive change.
Once again, with Subaru MAF-based engine management, it's not the temperature that is the problem, it's the change in the way the air flowing over the MAF creates its signal. Disrupting the factory setup is almost never a positive change.
