A Problem with CAI/SRIs and an Alternative (yes, finally) - Page 56

teslamaster · 10-20-2010, 10:12 PM

Quote:

Originally Posted by RaceFaceXC

The most effective means would be welding on the ports. I get the idea that welding isn't an option for you to do yourself, though.

An easy and probably still satisfactory means could be using riv nuts of the appropriate size. 1/4" should be about perfect. Use aluminum or stainless steel. other steels may cause corrosion issues with the alum intake pipe after a relatively short period of time, not to mention that they will rust.

These are Riv Nuts

Avoid using stainless with the aluminum pipe due to galvanic corrosion.

If you know someone who can TIG aluminum it wouldn't take them long to do it for you.

* Registered users of the site do not see these ads.

wmdoucette · 10-21-2010, 08:29 PM

Drilled holes, ran in shortend pipe thread nipples, epoxied... hasn't leaked in a year.

sr5.2 · 10-27-2010, 03:23 PM

Hey everyone,
Im new to the forum and pretty new to Subaru. Apologies if this has been answered already but I don't have the time to read through 56 pages...

I own a 2002 Impreza 2.5RS n/a, I believe that my car has a MAP sensor and this problem does not affect me in any way? Am I correct, partially correct?

Any help is great!

renyo · 10-27-2010, 03:36 PM

Quote:

Originally Posted by sr5.2

Hey everyone,
Im new to the forum and pretty new to Subaru. Apologies if this has been answered already but I don't have the time to read through 56 pages...

You're making a horrible first impression.

sr5.2 · 10-27-2010, 03:51 PM

I understand this but would it be possible at all for someone to tell me if I am right?
I have done a little research behind this that's how I 'guessed' that I have the MAP, Im just looking for a confirmation from a petrol-head. That's all, thanks in advance.

renyo · 10-27-2010, 04:04 PM

You want confirmation you have a MAP sensor, or you want confirmation that you don't have to worry about problems?

99% sure you have a MAP sensor. Unless you have a sensor with a 5 wire plug next to the airbox on the passenger side of the car, you have a MAP sensor.

If you're looking for confirmation that you don't have to worry about problems, then refer to my previous post.

williaty · 10-27-2010, 05:28 PM

Quote:

Originally Posted by sr5.2

Hey everyone,
Im new to the forum and pretty new to Subaru. Apologies if this has been answered already but I don't have the time to read through 56 pages...

I own a 2002 Impreza 2.5RS n/a, I believe that my car has a MAP sensor and this problem does not affect me in any way? Am I correct, partially correct?

Any help is great!

You are MAP based and therefore this problem doesn't apply to you.

Is this Opposite Day, or what? I just posted the concise, non-snarky answer. I think hell might just have frozen over.

sr5.2 · 10-29-2010, 03:45 PM

Thank you williaty! Im just not as experienced so I seek to my elders for advice

@renyo thanks too! And no, I wasn't looking for a confirmation that I won't have any problems...hehe, I bought a used car, I know how it works.

Thanks guys! Loving the forum

renyo · 10-29-2010, 11:26 PM

Oh, well sorry for being a bit of a ****. You wouldn't have been the first person to come to this thread and ask if the problem happened with the MAP sensor setup (if that was what you had actually been asking).

joey horvath · 11-03-2010, 11:40 AM

what happed to the good old days when a little trip to the plumbing department and canadian tire was all it took for a c a i

Soul Shinobi · 11-03-2010, 02:02 PM

Computerized fuel injection happened.

BlueMolecule · 11-07-2010, 08:35 PM

hey williaty would you help me build a hybrid intake. how far is deleware county from pittsburgh? trying to figure out what I would need to do this, its all scattered on this forum different model years and parts from ebay, going to search.

williaty · 11-07-2010, 08:38 PM

Yes, I'd help, but it's a damned long drive. Probably 5 hours one way.

BlueMolecule · 11-07-2010, 08:56 PM

Quote:

Originally Posted by williaty

Yes, I'd help, but it's a damned long drive. Probably 5 hours one way.

damn that is far, didnt look quite so distant on google maps. well maybe in the spring or something. I just remembered that i had subscribed to the 08 hybrid forum.

nasa779 · 11-09-2010, 08:31 PM

ive read about 10 pages of this so far and was just curious, did the maf spike occur at WOT or was the error proportional to the % of throttle

williaty · 11-09-2010, 08:34 PM

Quote:

Originally Posted by nasa779

ive read about 10 pages of this so far and was just curious, did the maf spike occur at WOT or was the error proportional to the % of throttle

It's proportional to the throttle opening. At low throttle opening angles it gets small enough you don't have to care about it.

nasa779 · 11-10-2010, 09:50 AM

I just think iits weird that no matter the amount of airflow going through the intake, the resonance is still there and it doesn't change what rpm it the resonance occurs

renyo · 11-10-2010, 10:07 AM

Well (if I understand it correctly) the resonance is caused by the intake valves and their timing.

Changing the throttle angle should just change how much of the wave is reflected back into the engine side of the intake. The more energy that's reflected back, the less energy that propagates into the MAF side of the intake. Less energy is less amplitude.

williaty · 11-10-2010, 12:45 PM

Quote:

Originally Posted by nasa779

I just think iits weird that no matter the amount of airflow going through the intake, the resonance is still there and it doesn't change what rpm it the resonance occurs

The resonance occurs at the RPM at which the valves are opening and closing at the same frequency as the resonant frequency of the intake tract. The resonant frequency of the intake tract is determined by the wavelength of the standing wave in the intake tract. The length of the standing wave in the intake tract is determined by the length of the intake tract itself. This is why the resonance always occurs at the same RPM: the intake tract is always the same length.

The really interesting question is why don't we see smaller resonances at octave multiples of the primary? I haven't figured that one out yet.

Quote:

Originally Posted by renyo

Well (if I understand it correctly) the resonance is caused by the intake valves and their timing.

Changing the throttle angle should just change how much of the wave is reflected back into the engine side of the intake. The more energy that's reflected back, the less energy that propagates into the MAF side of the intake. Less energy is less amplitude.

It's unclear if the throttle is determining the amplitude of the resonance via being an obstruction to the propagation of the wave or by controlling flow velocity.

Navi271 · 11-27-2010, 11:33 PM

Hmm, pretty much decided to get rid of my weapon R intake, and use the same pipe to make a hybrid. I'm wondering if this is why I seem to go slower at WOT than I do at just under WOT?

Either way, going back to stock kinda. I seem to be doing that a lot with my car lately. I think now that I'm older and wiser I see that the things I did to the car early on are not necessarily better for it. I've grown tired of the noise the SRI would make too. Can't wait for that to go away.

Soul Shinobi · 11-28-2010, 12:48 AM

Quote:

Originally Posted by Navi271

Hmm, pretty much decided to get rid of my weapon R intake, and use the same pipe to make a hybrid. I'm wondering if this is why I seem to go slower at WOT than I do at just under WOT?

Either way, going back to stock kinda. I seem to be doing that a lot with my car lately. I think now that I'm older and wiser I see that the things I did to the car early on are not necessarily better for it. I've grown tired of the noise the SRI would make too. Can't wait for that to go away.

I feel the same thing, faster just before WOT. I think it's the switchover to open loop, using preset fuel maps at WOT that are rich to protect the engine. I'd love to hear someone who knows exactly what happens explain it though.

Kevin Thomas · 11-29-2010, 01:20 AM

If you have an sri, is there any reason to believe that the air filter itself could be instigating the low end maf voltage spikes and that perhaps a different air filter will show a different result? I have a little experience with changing a Weapon R air filter on a dyno and the results were eye-opening (On a non-subaru vehicle). I just did not capture the air/fuel ratio down to that low of an rpm range (or maf voltage for that matter).

Also, couldn't an SAFC counter the running rich causing spike of an SRI so you have the best of both worlds?

williaty · 11-29-2010, 01:25 AM

No, this is being caused by the lack of a Helmholtz resonator, not the air filter.

No, an SAFC or other piggyback device can't do anything at all for this because of the way the ECU operates.

Kevin Thomas · 11-29-2010, 02:23 AM

Quote:

Originally Posted by williaty

No, this is being caused by the lack of a Helmholtz resonator, not the air filter.

No, an SAFC or other piggyback device can't do anything at all for this because of the way the ECU operates.

You were very specific in your original post -->
"This report applies to any MAF-based naturally-aspirated GD/GG H4 Subaru. Most of the people who will be interested in this are going to be 05 2.5RS owners and 06-07 2.5i owners."

My apologies!

I just ordered a bluetooth OBD2 elm scantool for the android phone right after reading this whole thing. Gonna download some OBD2 apps and check some logs. The 1997 Outback is turbocharged but it is still worth a look with this as well as a couple other cars. Thanks!

williaty · 11-29-2010, 02:31 AM

I'll be interested to see if a generic scan tool (aka anything other than RomRaider) can poll the ECU fast enough to catch this.

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10-21-2010, 08:29 PM	#1377
wmdoucette Scooby Newbie Member#: 192709 Join Date: Oct 2008 Chapter/Region: W. Canada Location: Calgary, AB CANADA Vehicle: 2007 2.5iSE Wagon CG 2001 2.5RS Coupe RBP	Drilled holes, ran in shortend pipe thread nipples, epoxied... hasn't leaked in a year.

10-27-2010, 03:23 PM	#1378
sr5.2 Scooby Newbie Member#: 250073 Join Date: Jun 2010 Chapter/Region: South East Location: Toronto Vehicle: 2002 Impreza RS	Hey everyone, Im new to the forum and pretty new to Subaru. Apologies if this has been answered already but I don't have the time to read through 56 pages... I own a 2002 Impreza 2.5RS n/a, I believe that my car has a MAP sensor and this problem does not affect me in any way? Am I correct, partially correct? Any help is great!

10-27-2010, 03:51 PM	#1380
sr5.2 Scooby Newbie Member#: 250073 Join Date: Jun 2010 Chapter/Region: South East Location: Toronto Vehicle: 2002 Impreza RS	I understand this but would it be possible at all for someone to tell me if I am right? I have done a little research behind this that's how I 'guessed' that I have the MAP, Im just looking for a confirmation from a petrol-head. That's all, thanks in advance.

10-27-2010, 04:04 PM	#1381
renyo Scooby Newbie Member#: 93577 Join Date: Aug 2005 Chapter/Region: MAIC Location: Orlando, unfortunately Vehicle: 98 Impreza	You want confirmation you have a MAP sensor, or you want confirmation that you don't have to worry about problems? 99% sure you have a MAP sensor. Unless you have a sensor with a 5 wire plug next to the airbox on the passenger side of the car, you have a MAP sensor. If you're looking for confirmation that you don't have to worry about problems, then refer to my previous post.

10-29-2010, 03:45 PM	#1383
sr5.2 Scooby Newbie Member#: 250073 Join Date: Jun 2010 Chapter/Region: South East Location: Toronto Vehicle: 2002 Impreza RS	Thank you williaty! Im just not as experienced so I seek to my elders for advice @renyo thanks too! And no, I wasn't looking for a confirmation that I won't have any problems...hehe, I bought a used car, I know how it works. Thanks guys! Loving the forum

10-29-2010, 11:26 PM	#1384
renyo Scooby Newbie Member#: 93577 Join Date: Aug 2005 Chapter/Region: MAIC Location: Orlando, unfortunately Vehicle: 98 Impreza	Oh, well sorry for being a bit of a ****. You wouldn't have been the first person to come to this thread and ask if the problem happened with the MAP sensor setup (if that was what you had actually been asking).

11-03-2010, 11:40 AM	#1385
joey horvath Scooby Newbie Member#: 209359 Join Date: Apr 2009 Chapter/Region: E. Canada Vehicle: 2004 obs woodland green/silver	what happed to the good old days when a little trip to the plumbing department and canadian tire was all it took for a c a i

11-03-2010, 02:02 PM	#1386
Soul Shinobi Scooby Newbie Member#: 130759 Join Date: Oct 2006 Chapter/Region: NESIC Location: Nashua, NH, USA Vehicle: 1992 Legacy L Sedan 1998 Legacy L Wagon	Computerized fuel injection happened.

11-07-2010, 08:35 PM	#1387
BlueMolecule Scooby Newbie Member#: 210006 Join Date: Apr 2009 Chapter/Region: MAIC Location: Pittsburgh Vehicle: 2008 Impreza 2.5i 4d Newport Blue	hey williaty would you help me build a hybrid intake. how far is deleware county from pittsburgh? trying to figure out what I would need to do this, its all scattered on this forum different model years and parts from ebay, going to search.

11-07-2010, 08:38 PM	#1388
williaty Scooby Guru Member#: 71092 Join Date: Sep 2004 Chapter/Region: MWSOC Location: Delaware County, Ohio Vehicle: 2005 2.5RS Wagon Regal Blue Pearl	Yes, I'd help, but it's a damned long drive. Probably 5 hours one way.

11-09-2010, 08:31 PM	#1390
nasa779 Scooby Newbie Member#: 263513 Join Date: Nov 2010 Chapter/Region: MAIC Location: allison park, PA (pittsburgh) Vehicle: 00 acura integra silver	ive read about 10 pages of this so far and was just curious, did the maf spike occur at WOT or was the error proportional to the % of throttle

11-10-2010, 09:50 AM	#1392
nasa779 Scooby Newbie Member#: 263513 Join Date: Nov 2010 Chapter/Region: MAIC Location: allison park, PA (pittsburgh) Vehicle: 00 acura integra silver	I just think iits weird that no matter the amount of airflow going through the intake, the resonance is still there and it doesn't change what rpm it the resonance occurs

11-10-2010, 10:07 AM	#1393
renyo Scooby Newbie Member#: 93577 Join Date: Aug 2005 Chapter/Region: MAIC Location: Orlando, unfortunately Vehicle: 98 Impreza	Well (if I understand it correctly) the resonance is caused by the intake valves and their timing. Changing the throttle angle should just change how much of the wave is reflected back into the engine side of the intake. The more energy that's reflected back, the less energy that propagates into the MAF side of the intake. Less energy is less amplitude.

11-27-2010, 11:33 PM	#1395
Navi271 Scooby Newbie Member#: 203099 Join Date: Feb 2009 Chapter/Region: MWSOC Location: Ankeny/Ames, IA Vehicle: 1995 Legacy Wagon Winter Green Metallic	Hmm, pretty much decided to get rid of my weapon R intake, and use the same pipe to make a hybrid. I'm wondering if this is why I seem to go slower at WOT than I do at just under WOT? Either way, going back to stock kinda. I seem to be doing that a lot with my car lately. I think now that I'm older and wiser I see that the things I did to the car early on are not necessarily better for it. I've grown tired of the noise the SRI would make too. Can't wait for that to go away.

11-29-2010, 01:20 AM	#1397
Kevin Thomas Street Racing Instructor Moderator Member#: 110 Join Date: Jul 1999 Location: 1997 OBS, 1996 SVX, 1988 RX Vehicle: 1989 1989 XT6	If you have an sri, is there any reason to believe that the air filter itself could be instigating the low end maf voltage spikes and that perhaps a different air filter will show a different result? I have a little experience with changing a Weapon R air filter on a dyno and the results were eye-opening (On a non-subaru vehicle). I just did not capture the air/fuel ratio down to that low of an rpm range (or maf voltage for that matter). Also, couldn't an SAFC counter the running rich causing spike of an SRI so you have the best of both worlds?

11-29-2010, 01:25 AM	#1398
williaty Scooby Guru Member#: 71092 Join Date: Sep 2004 Chapter/Region: MWSOC Location: Delaware County, Ohio Vehicle: 2005 2.5RS Wagon Regal Blue Pearl	No, this is being caused by the lack of a Helmholtz resonator, not the air filter. No, an SAFC or other piggyback device can't do anything at all for this because of the way the ECU operates.

11-29-2010, 02:31 AM	#1400
williaty Scooby Guru Member#: 71092 Join Date: Sep 2004 Chapter/Region: MWSOC Location: Delaware County, Ohio Vehicle: 2005 2.5RS Wagon Regal Blue Pearl	I'll be interested to see if a generic scan tool (aka anything other than RomRaider) can poll the ECU fast enough to catch this.