Welcome to the North American Subaru Impreza Owners Club Friday March 29, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
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.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 06-12-2004, 06:17 PM   #1
grozgon
Scooby Newbie
 
Member#: 48109
Join Date: Nov 2003
Location: Maple Shade, NJ
Vehicle:
2004 Subaru WRX
Silver

Default Cobb Stage 2 running very lean

So I installed Stage 2 with the AP a couple weeks ago, put it on the dyno today, got very good numbers, BUT running very lean. The guy that was running the dyno said, I should be very worried about it. Now, I don't know much about this stuff, but it got me worried. The tech suggested that I call Cobb and ask them about it, which I'm going to do on Monday.
I'm wondering if anyone else has this problem and if this could cause damage. I'll post the update after I talk to Cobb.

Thanks
* Registered users of the site do not see these ads.
grozgon is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 06-12-2004, 06:26 PM   #2
obsidianSTI
Scooby Newbie
 
Member#: 62870
Join Date: May 2004
Default

Do you by chance have an intake
obsidianSTI is offline   Reply With Quote
Old 06-12-2004, 06:31 PM   #3
grozgon
Scooby Newbie
 
Member#: 48109
Join Date: Nov 2003
Location: Maple Shade, NJ
Vehicle:
2004 Subaru WRX
Silver

Default

Quote:
Originally posted by obsidianSTI
Do you by chance have an intake
No sir, still running a stock intake. I've read too much stuff on here about intakes and BOV's.
grozgon is offline   Reply With Quote
Old 06-12-2004, 06:50 PM   #4
clamdip
Scooby Specialist
 
Member#: 18709
Join Date: May 2002
Default

what are your EGT's?
clamdip is offline   Reply With Quote
Old 06-12-2004, 07:03 PM   #5
grozgon
Scooby Newbie
 
Member#: 48109
Join Date: Nov 2003
Location: Maple Shade, NJ
Vehicle:
2004 Subaru WRX
Silver

Default

Quote:
Originally posted by clamdip
what are your EGT's?
Don't know. I have an EGT gauge sitting here, but didn't install it yet. I was scared of drilling through the manifold, but I'm going to do it within a week or so.
grozgon is offline   Reply With Quote
Old 06-12-2004, 07:37 PM   #6
dsmperformance
Scooby Specialist
 
Member#: 15059
Join Date: Feb 2002
Chapter/Region: MAIC
Location: Latrobe, PA
Vehicle:
2004 WRX STi
1991 TSi

Default

Do you have actual proof of running lean? Any a/f numbers?

If not, might wanna snag them from the dyno guy. I doubt Cobb will be able to do anything for you without some numbers.
dsmperformance is offline   Reply With Quote
Old 06-12-2004, 07:39 PM   #7
clamdip
Scooby Specialist
 
Member#: 18709
Join Date: May 2002
Default

Quote:
Originally posted by dsmperformance
Do you have actual proof of running lean? Any a/f numbers?

If not, might wanna snag them from the dyno guy. I doubt Cobb will be able to do anything for you without some numbers.
yeah, this sounds like a good idea. keep in mind, well, with my egt's and cobb stage 2 i would be around +/- 800 *C at WOT in 5th gear. however, in the lower gears, my EGT's rise fast up until about 650-700 or so. this is good for pre-spool and spool-up. then, it starts to fatten up on the high end. so a good tune would constitute with fast rising egt's down low then slowing down up high. you should check with the dyno guy and get your a/f and egt readings from him.

Last edited by clamdip; 06-12-2004 at 07:45 PM.
clamdip is offline   Reply With Quote
Old 06-12-2004, 07:48 PM   #8
grozgon
Scooby Newbie
 
Member#: 48109
Join Date: Nov 2003
Location: Maple Shade, NJ
Vehicle:
2004 Subaru WRX
Silver

Default

I have the print of the graph here. I'm getting around 15.1 A/F at full boost. It doesn't get more gas untill around 5200 RPM. From around 2500 RPM untill 5200 RPM it's running at 14.5 and higher. The guy at the dyno place told me this is very lean. I've been reading the cobb forum and it seem like people were complaining that they were running too lean and they were getting 12A/F. I'm getting more than that, and I'm getting very worried.


Any ideas guys?
grozgon is offline   Reply With Quote
Old 06-12-2004, 08:15 PM   #9
clamdip
Scooby Specialist
 
Member#: 18709
Join Date: May 2002
Default

okay, here is a good write up straight from Trey.

http://www.wrxforum.com/cgi-bin/ulti...3;t=004269;p=3

here is the full thread:

http://www.wrxforum.com/cgi-bin/ulti...=004269#000001

hope this helps. this seems to be what you're experiencing. i don't think you have to worry. seems scary though huh? i think that the guys at cobb are very experienced and know a whole lot of what they're doing. however, if you still have questions and still are a bit worried, then you should give them a call. however, after i read this when i first got my stage 2, i wasn't worried. i guess you could say that i put my faith in Cobb.
clamdip is offline   Reply With Quote
Old 06-12-2004, 09:58 PM   #10
Macabre
Scooby Specialist
 
Member#: 3841
Join Date: Jan 2001
Location: Sacramento, CA
Vehicle:
2004 WRX Wagon
UTEC+VF22+WI

Default

You can argue about how safe it is, and I don't think Cobb's supporters will ever let someone say they did something less than perfect, however safety or not you'd be leaving power on the table with those fuel ratios. However, I can't believe it's that lean and not melted into a puddle. You should investigate the shop's O2 sensor hookup being proper, more so than just asking them. Most likely it's just bad data. Do you possibly have an exhaust leak?
Macabre is offline   Reply With Quote
Old 06-12-2004, 10:02 PM   #11
clamdip
Scooby Specialist
 
Member#: 18709
Join Date: May 2002
Default

Quote:
Originally posted by Macabre
You can argue about how safe it is, and I don't think Cobb's supporters will ever let someone say they did something less than perfect, however safety or not you'd be leaving power on the table with those fuel ratios. However, I can't believe it's that lean and not melted into a puddle. You should investigate the shop's O2 sensor hookup being proper, more so than just asking them. Most likely it's just bad data. Do you possibly have an exhaust leak?
yeah, i too have a feeling that it's just bad data. also, what you should do is get that egt gauge installed asap, then you can monitor your own engine on your driving conditions. a dyno is good for tuning and measuring engine hp/torque, however, it can't match real world driving conditions, which is why, after a good dyno tune, most companies would do a little road tuning to perfect the tune in real-world conditions.
clamdip is offline   Reply With Quote
Old 06-13-2004, 09:10 AM   #12
Chuck H
Scooby Specialist
 
Member#: 20442
Join Date: Jun 2002
Chapter/Region: NESIC
Location: Chelmsford, MA
Vehicle:
2022 WRX Limited
WRB

Default

I'd have to agree on the bad data as well. If you were really running 15:1 A/F at full boost, your engine would already be toast by now. That's too lean for an N/A motor at full throttle and just insane for a forced induction motor.
Chuck H is offline   Reply With Quote
Old 06-13-2004, 04:30 PM   #13
grozgon
Scooby Newbie
 
Member#: 48109
Join Date: Nov 2003
Location: Maple Shade, NJ
Vehicle:
2004 Subaru WRX
Silver

Default

Quote:
Originally posted by Chuck H
I'd have to agree on the bad data as well. If you were really running 15:1 A/F at full boost, your engine would already be toast by now. That's too lean for an N/A motor at full throttle and just insane for a forced induction motor.
Well, data might be bad, but it did pretty much the same thing on 3 different runs. I'm still going to call Cobb tomorrow, just to make sure.

If the engine starts overheating because it's running lean, will I be able to see it on the temp gauge or do I need to have an EGT gauge?

Also, is there another way of checking A/F, other than dyno?

Last edited by grozgon; 06-13-2004 at 04:36 PM.
grozgon is offline   Reply With Quote
Old 06-13-2004, 04:59 PM   #14
Macabre
Scooby Specialist
 
Member#: 3841
Join Date: Jan 2001
Location: Sacramento, CA
Vehicle:
2004 WRX Wagon
UTEC+VF22+WI

Default

The engine overheating is not the problem- it's detonation and poor performance you'd see from air/fuel ratios like that. Since you're not complaining of those symptoms, it's hard to believe you're really running that lean. Again, check for exhaust leaks.

You can monitor AFR yourself with one of the many available wideband O2 sensor setups. The TXS Tuner is a nice one with lots of features but expensive. I use an LM-1 from innovatemotorsports.com.
Macabre is offline   Reply With Quote
Old 06-13-2004, 09:49 PM   #15
GameOver
Scooby Specialist
 
Member#: 23145
Join Date: Aug 2002
Location: soCal sux
Vehicle:
2004 WRX STi
BLUE

Default Re: Cobb Stage 2 running very lean

Quote:
Originally posted by grozgon
So I installed Stage 2 with the AP a couple weeks ago, put it on the dyno today, got very good numbers, BUT running very lean. The guy that was running the dyno said, I should be very worried about it. Now, I don't know much about this stuff, but it got me worried. The tech suggested that I call Cobb and ask them about it, which I'm going to do on Monday.
I'm wondering if anyone else has this problem and if this could cause damage. I'll post the update after I talk to Cobb.

Thanks
what do you call 'good numbers' ???

Im curious man!
GameOver is offline   Reply With Quote
Old 06-14-2004, 12:38 AM   #16
grozgon
Scooby Newbie
 
Member#: 48109
Join Date: Nov 2003
Location: Maple Shade, NJ
Vehicle:
2004 Subaru WRX
Silver

Default Re: Re: Cobb Stage 2 running very lean

Quote:
Originally posted by GameOver
what do you call 'good numbers' ???

Im curious man!
I got 221.5 whp I'd say that's pretty good for stage 2.
grozgon is offline   Reply With Quote
Old 06-14-2004, 12:47 AM   #17
GameOver
Scooby Specialist
 
Member#: 23145
Join Date: Aug 2002
Location: soCal sux
Vehicle:
2004 WRX STi
BLUE

Default



good #s
GameOver is offline   Reply With Quote
Old 06-14-2004, 01:01 AM   #18
Equilibrium Tuning
Former Vendor
 
Member#: 26933
Join Date: Oct 2002
Chapter/Region: BAIC
Location: Fairfield, CA
Vehicle:
2006 STI
CGM

Default

yep.. 221 is right about where it should be. Aside from the peak numbers, did the curve look smooth? If so, then I'd say there is no way you could have been running that lean.

-- Ed
Equilibrium Tuning is offline   Reply With Quote
Old 06-14-2004, 01:26 AM   #19
donmei
Scooby Newbie
 
Member#: 55101
Join Date: Feb 2004
Location: CT, U.S.A.
Vehicle:
2004 STI
Blue

Default

Macabre,

I recognize you from VW boards in the past. Is there anyway to pull a/f ratio from the car's ECU, like I seem to remember you could with the Vag Com??

is A/F ration part of the OBD II standard or an extended function?

Don
donmei is offline   Reply With Quote
Old 06-14-2004, 02:08 AM   #20
Equilibrium Tuning
Former Vendor
 
Member#: 26933
Join Date: Oct 2002
Chapter/Region: BAIC
Location: Fairfield, CA
Vehicle:
2006 STI
CGM

Default

More veedub guys? I was on vwvortex.com as well. You can pull a/f ratio using deltadash or any universal OBD-II logger, I believe. The problem is that the stock "wideband" O2 sensor on the suby is only accurate down to ~11.5:1.

-- Ed
Equilibrium Tuning is offline   Reply With Quote
Old 06-14-2004, 03:11 AM   #21
Macabre
Scooby Specialist
 
Member#: 3841
Join Date: Jan 2001
Location: Sacramento, CA
Vehicle:
2004 WRX Wagon
UTEC+VF22+WI

Default

The UTEC doesn't even consider it accurate that far down. And it's probably not terribly precise or responsive anywhere.

Anywho, standard OBDII scanners will not give you a reading from the stock front sensor. You'd need a deltadash to get that, for whatever good it will do you. If you're going to be tuning you should just bite the bullet and get a wideband setup.
Macabre is offline   Reply With Quote
Old 06-14-2004, 02:48 PM   #22
grozgon
Scooby Newbie
 
Member#: 48109
Join Date: Nov 2003
Location: Maple Shade, NJ
Vehicle:
2004 Subaru WRX
Silver

Default

Quote:
Originally posted by Vaus
yep.. 221 is right about where it should be. Aside from the peak numbers, did the curve look smooth? If so, then I'd say there is no way you could have been running that lean.

-- Ed
The curve is relatively smooth untill about 4800 rpm, that's when it drops, then starts going back up again.
grozgon is offline   Reply With Quote
Old 06-14-2004, 04:40 PM   #23
AZScoobie
Scooby Guru
 
Member#: 8785
Join Date: Jul 2001
Chapter/Region: SWIC
Vehicle:
02 c_turner@ix.
netcom.com

Default

I have now seen this over 6 times with the Cobb flash. I sent emails and spoke with Trey about it so he would know what I was seeing. There must be an odd problem in the calibration of the ECU. I believe him when he says he tunes for XX AFR and that his car/cars are showing that on his dyno.. But for some reason cars in other states (maybe altitude) are running lean AFR's. I had one car run at 12.5 to 1 almost across the board and a few I saw in the 13's and just let out of the gas on the dyno.. No point in potentialy hurting something. I did have one that ran near 11 to 1 and made good power.. So its not ALL Cobb ECu'[s on ALL cars..

Better Call Trey and fax him those charts.. You might have an issue with your fuel system or maybe an MAF leak or you might have an issue with the flash.

C
AZScoobie is offline   Reply With Quote
Old 06-14-2004, 04:44 PM   #24
Equilibrium Tuning
Former Vendor
 
Member#: 26933
Join Date: Oct 2002
Chapter/Region: BAIC
Location: Fairfield, CA
Vehicle:
2006 STI
CGM

Default

Quote:
Originally posted by grozgon
The curve is relatively smooth untill about 4800 rpm, that's when it drops, then starts going back up again.
When you say it drops, how much does it drop and does that drop coincide with a change in the a/f? Posting the chart would be very useful.

-- Ed
Equilibrium Tuning is offline   Reply With Quote
Old 06-14-2004, 05:03 PM   #25
MikeWRX-NJ
Scooby Specialist
 
Member#: 33410
Join Date: Feb 2003
Chapter/Region: Tri-State
Location: wishing i was somewhere else
Vehicle:
08 wrx
dgm

Default

i'd post in your regional forum to see if anyone in your area has a delta dash that can help you. although its not accurate below 12:1 or so... you'll still be able to see if at say 4800rpm you're running 15:1 or if the graph bottoms out. it's better than nothing.
MikeWRX-NJ 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 Stage 2 Lean rhurley13 AccessPort 6 04-22-2010 07:32 PM
Cobb Stage 2 Running Safely? bmw50021 AccessPort 3 11-22-2006 08:20 PM
Cobb stage 2 running lean. 06rexwagon AccessPort 2 07-12-2006 12:04 AM
STi Cobb stage 2 running rich or lean? SubaruBen Factory 2.5L Turbo Powertrain (EJ Series Factory 2.5L Turbo) 8 10-14-2005 12:48 PM
my cobb stage 2 running lean!!! swol3 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 17 09-18-2004 07:55 AM

All times are GMT -4. The time now is 08:42 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.