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Old 09-11-2003, 08:10 PM   #26
horshack
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I did a little dyno research with a drop in/silencer mod vs a injen "type" CAI.

While the injen "type" CAI made 3-4 more HP than the drop in with silencer mod on the STi, this was mainly due to leaning the car out a little, plus the additional volume of air passing by the MAF made it work much harder.

Due to the harsh effect on the A/F the MAF had, I went back to the drop in w/silencer mod until I can tune for the CAI with a slightly larger piping.

If the APS is truly the same size as the stock MAF hosing diameter, then it would make sense that is a viable option.

Just have to weigh the cost of a drop in vs the APS CAI and is it worth 3-4 HP?

Just my 2c.
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Old 09-11-2003, 08:32 PM   #27
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Quote:
Originally posted by horshack

Due to the harsh effect on the A/F the MAF had, I went back to the drop in w/silencer mod until I can tune for the CAI with a slightly larger piping.
This is the exact reason I removed my TXS intake and MBC. I guess the DP and exhaust will suffice until UTEC or reflash.
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Old 09-11-2003, 09:43 PM   #28
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Quote:
Originally posted by horshack

If the APS is truly the same size as the stock MAF hosing diameter, then it would make sense that is a viable option.

Just have to weigh the cost of a drop in vs the APS CAI and is it worth 3-4 HP?
APS tell you straight up that your car needs to be tuned after the install of there CAI.
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Old 09-11-2003, 09:44 PM   #29
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Quote:
Originally posted by dsmperformance
"Due to the harsh effect on the A/F the MAF had, I went back to the drop in w/silencer mod until I can tune for the CAI with a slightly larger piping." - horshack

This is the exact reason I removed my TXS intake and MBC. I guess the DP and exhaust will suffice until UTEC or reflash.
So what MAF issues did you have and what were your A/Fs before and after the install of the TXS intake?
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Old 09-11-2003, 10:46 PM   #30
STiLL WILL
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To all the guys with the 65mm APS CAI on their STi's...where did you guys order them from?

-STiLL
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Old 09-12-2003, 12:14 AM   #31
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Quote:
Originally posted by metoo


So what MAF issues did you have and what were your A/Fs before and after the install of the TXS intake?
I didn't have any MAF issues at all and don't have any A/F numbers for ya. It ran really awesome, but the long term reliability issues is what i'm concerned with. I am also concerned with the DET issues which seemed to come back after being DET free after break-in. Just trying to play it safe until the DET issues are taken care of.
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Old 09-12-2003, 12:18 AM   #32
enewtabie
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I wouldnt mess with the intake..I know a friend putting down 353 hp with the stock intake on his wrx.
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Old 09-12-2003, 03:03 AM   #33
solberg wantabee
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Default HKS and Zerosports

I have the HKS Super Mega Flow intake with the Zerosports intake pipe. I have also done the intake silencer mod(cut off the lower portion of the silencer and sealed it with a piece of plastic to make it a u bend, ghetto but does the job). As previous people have said it sounds awsome. HKS seems the most common intake in the UK so I thought I'd give it a try. Absolutely no CEL's.
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Old 09-12-2003, 07:58 AM   #34
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Blitz SUS. Made 10 whp on a mostly stock WRX over a drop in filter. Made about 15 whp on my STi with just downpipe. Simply amazing. No other intake I've tried has done that.
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Old 09-12-2003, 09:20 AM   #35
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Quote:
Originally posted by god
Blitz SUS. Made 10 whp on a mostly stock WRX over a drop in filter. Made about 15 whp on my STi with just downpipe. Simply amazing. No other intake I've tried has done that.
Was this with or without engine tuning modifications?
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Old 09-12-2003, 10:28 AM   #36
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I have the Apexi Gt-spec exhaust and he realitively unknown Apexi Power Intake with the air intake heatshield kit. No cels or apparent effect on gas mileage. It definitely sounds better and it definitely pulls harder. No proof though as I have not dyno'd the car nor have I installed my gauges yet.

Soon.... Apexi gauges and a hopefully a Godspeed downpipe when they get caught up.....

George
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Old 09-12-2003, 01:11 PM   #37
zacek
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any APS authorized dealer will carry the new 65mm intake.

see www.aps-wrx.com for list

but if you must have a contact now:

www.fi-systems.com (jason) phone in website. (texas)

www.isrperformance.com (pam) phone in website. (So. Calif.)
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Old 09-12-2003, 01:17 PM   #38
STiLL WILL
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Quote:
Originally posted by zacek
any APS authorized dealer will carry the new 65mm intake.

see www.aps-wrx.com for list

but if you must have a contact now:

www.fi-systems.com (jason) phone in website. (texas)

www.isrperformance.com (pam) phone in website. (So. Calif.)
Thank you Zacek. I was beginning to think that my post was forgotten.

Thanks again,

-STiLL
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Old 09-12-2003, 01:20 PM   #39
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Quote:
Originally posted by Nivek-CA
Zacek - I live in the area. Are you going to the Socal meeting off Mason and Devonshire on Thursday night? Can I get a ride in your STI? I would really like to see what those modifications both feel and sound like because I have been told that without the ECU upgrade, not much can be gained from making similar modifications.
IS true that a CAI by itself on a WRX/STi will not gain significant HP increase on a otherwise stock car. But in my case I will eventually have my ECU reflashed (ECUtek) with the following parts:

Upgrade intake and turbo back. (including headers)
Upgraded turbo (maybe APS SR-50, or PE1820, or Shiv's new turbo)
Upgraded injectors.
STi lighweight 6MT Flywheel.

I'm pretty darn sure that the High Flow intake will oversee some HP advantage over the stock paper-filter intake for this kind of mods.

Also, regarless of tuning or not. Any High Flow intake will improve responsiveness of the car specially in the low end. So that by itself is well worth it. Once again, this applies when the MAF sensor does not get affected.
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Old 09-12-2003, 06:04 PM   #40
singletrack
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Quote:
Originally posted by zacek
All I can say is this:

I own a U.S. 2004 STi, no SOA reflash yet. Pings very mildly.

I installed all together:

APS Turbo-Back 3" to 2.5" muffler. (from old WRX)
APS 65mm intake (bought a new one, old one was the 70mm)

HUGEASS difference in response and acceleration. My car must be making about 330+bHP from the allegadly stock 300bhp.

Luck or not I have not got a single CE light yet, either from the intake nor the Exhaust.

Side effects:

Faster more responsive car.
Keeps accelerating after 5k rpms to almost redline.
stock boost got raised and now peaks at 16psi sometimes, specialy during downshifts and then WOT.
A/F Ratios settled after a couple of days. Waiting to install EGT probe on aftermarket up-pipe.

A little too loud during acceleration (both intake and exhaust). However the perfomance makes me forget about the noise.

Next upgrades: HKS headers and HELIX up-pipe (for EGT probe)
If the car shoots to 16PSI on shifts, than I would guess that the ECU/ECM cannot actuate the wastegate fast enough with the bigger downpipe/exhaust combo. I would assume that boost level is still fine for the VF39 so if it doesn't spike higher (anyone have a map?), it sounds nice.

Feel free to correct anyone if I am way off base : )

-st
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Old 09-12-2003, 06:06 PM   #41
singletrack
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Quote:
Originally posted by horshack
I did a little dyno research with a drop in/silencer mod vs a injen "type" CAI.

While the injen "type" CAI made 3-4 more HP than the drop in with silencer mod on the STi, this was mainly due to leaning the car out a little, plus the additional volume of air passing by the MAF made it work much harder.

Due to the harsh effect on the A/F the MAF had, I went back to the drop in w/silencer mod until I can tune for the CAI with a slightly larger piping.

If the APS is truly the same size as the stock MAF hosing diameter, then it would make sense that is a viable option.

Just have to weigh the cost of a drop in vs the APS CAI and is it worth 3-4 HP?

Just my 2c.
Forgive me if this has been previously discussed. Is the issue a limitation with the stock MAF, a programing issue, or a limit of the stock fuel injectors? Thanks for any info.

I just read in some crappy mag (can't remember which) that they removed the filter and threw it on the dyno and lost 8 HP.

-st
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Old 09-12-2003, 06:11 PM   #42
singletrack
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Quote:
Originally posted by singletrack


If the car shoots to 16PSI on shifts, than I would guess that the ECU/ECM cannot actuate the wastegate fast enough with the bigger downpipe/exhaust combo. I would assume that boost level is still fine for the VF39 so if it doesn't spike higher (anyone have a map?), it sounds nice.

Feel free to correct me anyone if I am way off base : )

-st
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Old 09-13-2003, 09:58 AM   #43
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Default Re: HKS and Zerosports

Quote:
Originally posted by solberg wantabee
I have the HKS Super Mega Flow intake with the Zerosports intake pipe.....

Ah yes, then you are also basically using no air filter. You want to
check on filtering tests, man. I ran this filter on both my previous
cars and you should SEE how black the engine oil gets at
changes. A portion of all that extra crap that gets by the filter
ends up in your oil. After seeing my oil sometimes I'd wonder how
the car still ran...


-Sporty
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Old 09-13-2003, 10:59 AM   #44
horshack
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Quote:
Originally posted by singletrack


Forgive me if this has been previously discussed. Is the issue a limitation with the stock MAF, a programing issue, or a limit of the stock fuel injectors? Thanks for any info.

I just read in some crappy mag (can't remember which) that they removed the filter and threw it on the dyno and lost 8 HP.

-st
The issue is this: the stock MAF is calibrated for a particular diameter pipe, it knows the amount of air that passes through this pipe. When you enlarge the diameter of the pipe, the MAF cant see the extra volume of air, but all the other engine sensors can. Thus the computer continously checks the MAF because everything else it telling it there is more air in the chamber than what the MAF is saying.

This condition can be corrected with ECU programing.

To the point above, I know of a 02 WRX that is making 396 WHP on the stock box with a drop in. So if the stock box can support almost 400 WHP then I think it should work for most applications.
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Old 09-13-2003, 11:46 AM   #45
singletrack
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Quote:
Originally posted by horshack


The issue is this: the stock MAF is calibrated for a particular diameter pipe, it knows the amount of air that passes through this pipe. When you enlarge the diameter of the pipe, the MAF cant see the extra volume of air, but all the other engine sensors can. Thus the computer continously checks the MAF because everything else it telling it there is more air in the chamber than what the MAF is saying.

This condition can be corrected with ECU programing.

To the point above, I know of a 02 WRX that is making 396 WHP on the stock box with a drop in. So if the stock box can support almost 400 WHP then I think it should work for most applications.
Thanks. So someone actually sold an intake with a larger diameter where the MAF actually plugs in? Or is the issue that the larger pipe pre-MAF causes turbulence and the MAF can't get a decent reading?

Thanks again,

-st
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Old 09-13-2003, 02:56 PM   #46
horshack
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Quote:
Originally posted by singletrack


Thanks. So someone actually sold an intake with a larger diameter where the MAF actually plugs in? Or is the issue that the larger pipe pre-MAF causes turbulence and the MAF can't get a decent reading?

Thanks again,

-st

Actually both.

Its amazing even what a milimeter or two will do.
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Old 09-13-2003, 04:19 PM   #47
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Quote:
Originally posted by horshack



Actually both.

Its amazing even what a milimeter or two will do.
Cool - thanks again.

-st
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Old 09-13-2003, 05:04 PM   #48
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One thing you guys seemed to not have tried, is cutting the front of the air box in the fender off (that butt ugly box at the bottom of the plastic intake hoses). This in effect sort of makes it not only a CAI, but a ram intake as well. Worked wonders on my WRX, and was way better than the MRT POD filter I was using.
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Old 09-13-2003, 05:04 PM   #49
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Default Re: Re: HKS and Zerosports

Quote:
Originally posted by SportyBry



Ah yes, then you are also basically using no air filter. You want to
check on filtering tests, man. I ran this filter on both my previous
cars and you should SEE how black the engine oil gets at
changes. A portion of all that extra crap that gets by the filter
ends up in your oil. After seeing my oil sometimes I'd wonder how
the car still ran...


-Sporty
If there is some "crap" getting past the filter and through the intake, how is it ending up in your crankcase?
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