Welcome to the North American Subaru Impreza Owners Club Monday July 28, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Engine Management & Tuning

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 02-24-2004, 08:28 PM   #1
daveyboy
Scooby Specialist
 
Member#: 35419
Join Date: Apr 2003
Default 17 psi on cobb stage 2 normal?

quick question:

I am hitting 17 psi of boost with my Cobb stage 2 91 octane map. My other mods are txs uppipe, stealth back, scorpion axle back, and K&N panel filter. I have been running this for a month or 2 and just now added an autometer carbon fiber mechanical boost gauge. I also live a 6000' and thought that I had read people indicating that you will not see as much boost at such a high elevation. I have not noticed any knocking or anything else detrimental. Although I believe my uppipe is leaking when the car is cold... .
* Registered users of the site do not see these ads.
daveyboy is offline   Reply With Quote
Old 02-24-2004, 11:53 PM   #2
WRXVII
Scooby Specialist
 
Member#: 15854
Join Date: Feb 2002
Location: Upstate NY
Vehicle:
2002 WRX
VF34'd...

Default

You are lucky... my car hits only 15psi....
WRXVII is offline   Reply With Quote
Old 02-25-2004, 04:11 AM   #3
skywalker
Scooby Specialist
 
Member#: 1990
Join Date: Jul 2000
Location: San Diego, CA
Default

At higher elevations the ECU has already been calibrated to adjust the amount of air it will allow to flow through the system.

Though everyone needs to take into consideration that there are different variables that can change boost pressures from car to car. Here are some of them that the ECU has already defined and uses to adjust boost.

1. Intake Air Temp
2. Barametric Pressure

Also these adjust multiple parameters within the stock ECU itself, whcih in turn adjust other variables. It is a crazy system, btu works amazingly well.

Also a simple question what gear were you in for 15 PSI or 17 PSI? Where were you in the RPM's? Where you at full throttle?

There are so many questions of what the boost should actually be at, as the system is constantly changing to adjust for so many different variables. The ECU is very smart and harnessing that power takes a lot of time, effort, knowledge and understanding.

Sure pays to be a computer science engineer that tunes cars all day for a living.

Cheers,
Bill Knose
I-Speed USA
skywalker is offline   Reply With Quote
Old 02-25-2004, 10:46 AM   #4
daveyboy
Scooby Specialist
 
Member#: 35419
Join Date: Apr 2003
Default

I was hitting 17 psi at full-throttle in the upper rpm range and, if I remember correctly, in 2nd, 3rd, and 4th gears. I shifted pretty early out of 1st so I am not sure how much psi I would hit, and I started to run out of "test road" once in 5th gear.
daveyboy is offline   Reply With Quote
Old 02-25-2004, 01:09 PM   #5
havoc
Scooby Newbie
 
Member#: 7603
Join Date: Jun 2001
Location: Centreville, VA
Vehicle:
2002 Impreza WRX
wrb

Default

I've seen as high as 18.3psi (in 4th) this winter in the colder weather. I'm sure it will return to the 16s when things warm up again.
havoc is offline   Reply With Quote
Old 02-25-2004, 02:19 PM   #6
clamdip
Scooby Specialist
 
Member#: 18709
Join Date: May 2002
Default

is your boost gauge accurate? maybe it's reading a bit high? i wouldn't say that it's normal, but since it's a well tuned ECU, then i guess 17psi isn't bad. how are your egt's? that would be a good sign if it's good or bad.
clamdip is offline   Reply With Quote
Old 02-25-2004, 08:36 PM   #7
daveyboy
Scooby Specialist
 
Member#: 35419
Join Date: Apr 2003
Default

Quote:
Originally posted by clamdip
is your boost gauge accurate? maybe it's reading a bit high? i wouldn't say that it's normal, but since it's a well tuned ECU, then i guess 17psi isn't bad. how are your egt's? that would be a good sign if it's good or bad.
Unfortunately, I do not have an egt gauge. I have held off buying one since I am running a pre-engineered reflash that still utilizes much of the stock ecu's safety settings--I am not sure if it is necessary.
daveyboy is offline   Reply With Quote
Old 02-25-2004, 09:22 PM   #8
clamdip
Scooby Specialist
 
Member#: 18709
Join Date: May 2002
Default

Quote:
Originally posted by daveyboy
Unfortunately, I do not have an egt gauge. I have held off buying one since I am running a pre-engineered reflash that still utilizes much of the stock ecu's safety settings--I am not sure if it is necessary.
true, however it's always good to know what's happening inside your engine. an EGT gauge will tell you exactly what's going on good or bad with your engine. let's just say that if your EGT's are high (around 900*C or higher) it would be bad to sustain boost levels around 17psi on the stock turbo. this could be an indication of the stocker being out of it's efficiency range therefore blowing hot air. well, it could all be just theoretical.
clamdip is offline   Reply With Quote
Old 02-26-2004, 05:58 AM   #9
skywalker
Scooby Specialist
 
Member#: 1990
Join Date: Jul 2000
Location: San Diego, CA
Default

Quote:
Originally posted by clamdip
true, however it's always good to know what's happening inside your engine. an EGT gauge will tell you exactly what's going on good or bad with your engine. let's just say that if your EGT's are high (around 900*C or higher) it would be bad to sustain boost levels around 17psi on the stock turbo. this could be an indication of the stocker being out of it's efficiency range therefore blowing hot air. well, it could all be just theoretical.
Agreed, though if the stock EGT is still in place, the highest the EGT's will read before a CEL is thrown is 892 degrees C. So if you still have it in there, you should be fine. IF you don not then it would be recommended to put the stock one back in or install a new one.

Cheers,
Bill Knose
I-Speed USA
www.i-speed.us
skywalker is offline   Reply With Quote
Old 02-26-2004, 04:05 PM   #10
digitalmethods
Scooby Specialist
 
Member#: 33734
Join Date: Mar 2003
Chapter/Region: NESIC
Location: Worcester, MA
Vehicle:
2002 used to be cool
02' Snow donkey FTL

Default

In third and fourth I hit pretty high boost levels too. I also live in Mass which has been as cold as a witches ass lately. I think once the air warmes up again my boost will be hitting lower levels.
digitalmethods is offline   Reply With Quote
Old 02-27-2004, 03:41 PM   #11
Equilibrium Tuning
NASIOC Vendor
 
Member#: 26933
Join Date: Oct 2002
Chapter/Region: BAIC
Location: Fairfield, CA
Vehicle:
2006 STI
CGM

Default

Quote:
Originally posted by skywalker
Sure pays to be a computer science engineer that tunes cars all day for a living.

Cheers,
Bill Knose
I-Speed USA
Cheers to that... I always thought computer engineers make the best tuners

-- Ed
Equilibrium Tuning is offline   Reply With Quote
Old 02-27-2004, 11:37 PM   #12
grozgon
Scooby Newbie
 
Member#: 48109
Join Date: Nov 2003
Location: Maple Shade, NJ
Vehicle:
2004 Subaru WRX
Silver

Default

Isn't 17psi or more not safe for the stock turbo? I always thought 17psi was the max for the stock and it would cause problems to run it that high.
grozgon is offline   Reply With Quote
Old 02-28-2004, 12:04 AM   #13
totoherbs
Scooby Guru
 
Member#: 7321
Join Date: Jun 2001
Chapter/Region: NESIC
Location: waltham, ma
Vehicle:
.... 122 IggPoints
Work... ahhh... so tired.

Default

Quote:
Originally posted by grozgon
Isn't 17psi or more not safe for the stock turbo? I always thought 17psi was the max for the stock and it would cause problems to run it that high.
The prodrive kit hits 18... an no its not a problem at peek of the powerband. If holding that to redline then yes, 16.5 is maxing out the stocker at redline....
totoherbs is offline   Reply With Quote
Old 02-29-2004, 12:58 PM   #14
Happy_Days
Scooby Specialist
 
Member#: 35049
Join Date: Apr 2003
Chapter/Region: VIC
Location: Vancouver BC
Vehicle:
2011 Mercedes C63
OE Tune 538/500

Default Re: 17 psi on cobb stage 2 normal?

Quote:
Originally posted by daveyboy
quick question:

I am hitting 17 psi of boost with my Cobb stage 2 91 octane map. My other mods are txs uppipe, stealth back, scorpion axle back, and K&N panel filter. I have been running this for a month or 2 and just now added an autometer carbon fiber mechanical boost gauge. I also live a 6000' and thought that I had read people indicating that you will not see as much boost at such a high elevation. I have not noticed any knocking or anything else detrimental. Although I believe my uppipe is leaking when the car is cold... .
I live at sea level and i hit 17lbs, but only briefly. I'd say average 16.5lbs.
Happy_Days is offline   Reply With Quote
Old 03-01-2004, 03:25 PM   #15
The Professor
Scooby Newbie
 
Member#: 23183
Join Date: Aug 2002
Chapter/Region: Tri-State
Location: PA
Vehicle:
2002 Cobb StageIIWRX
WR Blue

Default

16.5 was the highest I ever used to get. Just got the car back last Wed from 30k service and they reset the ECU, so while attempting to *ahem* "train" it on the freeway this past Sunday I recorded 17psi at WOT in 3rd or 4th gear. I guess it is re-learning and maybe I will lose this extra .5 of boost...although it's relearning with fresh plugs, tune, fuel filter, air filter and all of that. I seem to remember the car having brief moments of violent and sudden power when I first got the ECU also and that it calmed down slightly after about a tank of gas (200 miles or so).

Still does not seem like it should be possible since the ECU is electronically aiming for that 15.7 target. You would think a computer could get closer to 15.7 than 17.

Oh and innacurate gauges and differeing set ups (2 ways to install) could also account.

Last edited by The Professor; 03-01-2004 at 04:02 PM.
The Professor is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
cobb downpipe install whistling noise? 17.5 psi on perrin stage 2 91 broncofangene AccessPort 17 07-27-2009 02:50 PM
Just hitting 14 psi on cobb stage 2 map instead of 16psi wrxgeneration Newbies & FAQs 19 04-13-2008 06:30 PM
17 PSI on cobb stage 2 mars636 Engine Management & Tuning 21 12-01-2005 06:01 PM
Is there a thread on Cobb Stage 2 vs. Prodrive Stage 3 Power Pack? casualsurfer Newbies & FAQs 4 05-03-2004 05:06 PM
12's on cobb stage 2 ? cre Proven Power Bragging 4 10-15-2003 10:15 AM


All times are GMT -4. The time now is 04:59 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.