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Old 05-12-2013, 02:12 PM   #1
lvlatthew
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Member#: 336712
Join Date: Nov 2012
Location: massachusetts
Vehicle:
2002 bugeye wrx
silver

Default Help: Minor detonation while in 2nd gear

So I was coming down a road and downshifted into 2nd gear didn't actually slow me down much but it was in the process of slowing me down and I could head what sounded like a exhaust detonation like when you downshift. But it was constant and a lot quieter. Does anyone know what this could be?
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Old 05-12-2013, 03:21 PM   #2
fivestringslinger
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Member#: 200455
Join Date: Jan 2009
Chapter/Region: NESIC
Location: Connecticut
Vehicle:
2004 WRX Wagon, WRB
06 Triumph Speed Triple

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Judging by your description, it sounds like what you're experiencing is "afterfire", not detonation. Have you ever experienced this before? Have you changed anything on the car recently? What are your mods?
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Old 05-12-2013, 08:36 PM   #3
lvlatthew
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Member#: 336712
Join Date: Nov 2012
Location: massachusetts
Vehicle:
2002 bugeye wrx
silver

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Quote:
Originally Posted by fivestringslinger View Post
Judging by your description, it sounds like what you're experiencing is "afterfire", not detonation. Have you ever experienced this before? Have you changed anything on the car recently? What are your mods?
I drove again and it doesn't do it anymore but I have never heard it before maybe because I don't usually drive with my windows down but my mod list is
Let me find it ill edit it in:

Extras & Mods:
Subaru security upgrade
Pioneer DEH-P7000BT BlueTooth Receiver (phone and audio BlueTooth)
Whiteline Group 4 Coilovers (adjustable in height via strut body, bump & rebound via knob)
STI Strut Top Mounts
Whiteline Steering Rack Bushings
Turn-in Concepts Rear Diff Bushings
Turn-in Concepts Outrigger Bushings
Turn-in Concepts Fender Braces
Turn-in Concepts Shifter Bushings
Perrin Adjustable Rear Sway Bar
Energy Suspension rear sway bar urethane bushings
Perrin End-Links
Cusco Rear Strut Tower Bar with V-Brace
STI Engine Mount Bushings
K&N Air Filter
Turbo-XS 2" Stainless Turbo Back Exhaust
PDE Flex Up-pipe
Kartboy Exhaust Hangers
Kartboy Short Shifter
Kartboy Shift Knob
Enkei RPF1 17x7.5 Wheels
Custom Aluminum Centering Rings/Spacers
Pirelli P Zero Nero Tires
StopTech Braided Brake Lines
SpeedBleeders
Greddy, Peek/Hold/Warn Boost Gauge (silver)
Cobb Tuning Access Port -- Stage 2 Map Loaded
ABS Switch Mod
Fog Light with High Beams on Mod
EGT (catless) resistor mod
Grounding Mod
New Windshield (Oct 2012)
New Clutch (Jan 2010)
Estimated Power: HP: 280 / Torque: 285 ft-lbs
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Old 05-12-2013, 09:03 PM   #4
fivestringslinger
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Join Date: Jan 2009
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Location: Connecticut
Vehicle:
2004 WRX Wagon, WRB
06 Triumph Speed Triple

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Quote:
Originally Posted by lvlatthew View Post
I drove again and it doesn't do it anymore but I have never heard it before maybe because I don't usually drive with my windows down but my mod list is
Sounds like a pretty nice list! I'm running a very similar Stage 2 setup on my 04 wagon and I get the same thing on decel. Just a very light popping through the exhaust, especially if you lean into the throttle briefly and then quickly let off. It's normal. This is directly from COBB's site:

Quote:
From Paul Yaw of Injector Dynamics:

In any port injected system, there is a film of liquid fuel clinging to the walls of the intake runner.
During high vacuum conditions, this fuel is stripped from the surface, and pulled into the combustion chamber.
Because the throttle is closed, there is not enough oxygen to support combustion. The fuel ignites when it comes into contact with the oxygen at the end of the exhaust pipe.
Note that this occurs even with decel fuel cut.
The fuel that clings to the runner wall, and its response during transient conditions was described in detail by an engineer at Ford in 1981.
It is the basis of most current transient fuel correction strategies.
It is known as the X-Tau method, and it is explained clearly on the Megasquirt website.
Link here: https://cobbtuning.zendesk.com/entri...-Decelleration

I wouldn't worry as long as it's not doing it excessively. I live right in CT, so if you'd ever like to meet up sometime I'd be happy to take a listen for you. Also, if you haven't already updated your base map to the most recent version (3.10), go and download it and flash that in. I updated mine over the weekend (from v1.30...I was WAY behind) and it's a lot more smooth and refined.

Cheers!

Last edited by fivestringslinger; 05-12-2013 at 09:05 PM. Reason: Oh yeah, that too!
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Old 05-12-2013, 09:57 PM   #5
lvlatthew
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Location: massachusetts
Vehicle:
2002 bugeye wrx
silver

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I just bought the car in November and that is all from the previous owner so I most likely haven't done it. I'm actually worried to mess up anything with the ap but ill plug it in an update. Thanks!

Ya I actually have zero idea how to even hook up or update any of this and really don't feel like messing up my stuff. Ill have to do some research before doing anything

Last edited by lvlatthew; 05-12-2013 at 10:09 PM.
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Old 05-12-2013, 10:08 PM   #6
fivestringslinger
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Join Date: Jan 2009
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Location: Connecticut
Vehicle:
2004 WRX Wagon, WRB
06 Triumph Speed Triple

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Quote:
Originally Posted by lvlatthew View Post
I just bought the car in November and that is all from the previous owner so I most likely haven't done it. I'm actually worried to mess up anything with the ap but ill plug it in an update. Thanks!
In that case, make sure the previous owner doesn't have a custom tune currently flashed before you go changing anything. If that were the case, changing to one of the off-the-shelf (OTS) COBB maps might not be doing you any favors!

The AP is really easy to use and flash with. If you don't have any, you can download a PDF manual right from COBB's site. Make sure to read and understand it before you do anything and you should be fine!
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Old 05-12-2013, 10:10 PM   #7
lvlatthew
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Member#: 336712
Join Date: Nov 2012
Location: massachusetts
Vehicle:
2002 bugeye wrx
silver

Default

Quote:
Originally Posted by fivestringslinger View Post

In that case, make sure the previous owner doesn't have a custom tune currently flashed before you go changing anything. If that were the case, changing to one of the off-the-shelf (OTS) COBB maps might not be doing you any favors!

The AP is really easy to use and flash with. If you don't have any, you can download a PDF manual right from COBB's site. Make sure to read and understand it before you do anything and you should be fine!
I know the guy used stage 2 93 octane from the ap I know this for a fact

And he also said he only used it once or twice and the receipt he has from when he bought it was in 2004. So it's probably been a long Time since its been updated and like retuned the same map.

Last edited by lvlatthew; 05-12-2013 at 10:16 PM.
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Old 05-12-2013, 10:18 PM   #8
fivestringslinger
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Join Date: Jan 2009
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Location: Connecticut
Vehicle:
2004 WRX Wagon, WRB
06 Triumph Speed Triple

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Quote:
Originally Posted by lvlatthew View Post
I know the guy used stage 2 93 octane from the ap I know this for a fact
Good deal. Just making sure I wasn't giving you any bunk advice!

And yeah. If he only used it a couple of times since 04 the firmware on the AP and the current base map is probably way out of date.
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Old 05-12-2013, 10:20 PM   #9
lvlatthew
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Member#: 336712
Join Date: Nov 2012
Location: massachusetts
Vehicle:
2002 bugeye wrx
silver

Default

Quote:
Originally Posted by fivestringslinger View Post

Good deal. Just making sure I wasn't giving you any bunk advice!
I appreciate it. Well tomorrow after work I will look into giving it an update is this something I do with the cd that comes with the ap?
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Old 05-12-2013, 10:27 PM   #10
fivestringslinger
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Member#: 200455
Join Date: Jan 2009
Chapter/Region: NESIC
Location: Connecticut
Vehicle:
2004 WRX Wagon, WRB
06 Triumph Speed Triple

Default

Quote:
Originally Posted by lvlatthew View Post
I appreciate it. Well tomorrow after work I will look into giving it an update is this something I do with the cd that comes with the ap?
Nope! It's all done online.

Head over to COBB's site and click on the 'MAPS' tab. There's a link there to download Accessport Manager. There's also a tutorial video there.

Install the software and follow the instructions. It will automatically check for firmware updates and ask you if you want to install them.

Do you have the Version 2 Accessport (color screen)? If so, you probably have the AP itself, a USB to mini-USB cable, and a red/grey OBD2 "dongle" that you plug in under your dash, right? In that case, make sure you plug the "dongle" part into your computer as well while you have AP manager open to see if there are any firmware updates for that.

Last edited by fivestringslinger; 05-12-2013 at 10:39 PM. Reason: Department of Redundancy Department
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Old 05-13-2013, 07:53 AM   #11
lvlatthew
Scooby Newbie
 
Member#: 336712
Join Date: Nov 2012
Location: massachusetts
Vehicle:
2002 bugeye wrx
silver

Default

Quote:
Originally Posted by fivestringslinger View Post

Nope! It's all done online.

Head over to COBB's site and click on the 'MAPS' tab. There's a link there to download Accessport Manager. There's also a tutorial video there.

Install the software and follow the instructions. It will automatically check for firmware updates and ask you if you want to install them.

Do you have the Version 2 Accessport (color screen)? If so, you probably have the AP itself, a USB to mini-USB cable, and a red/grey OBD2 "dongle" that you plug in under your dash, right? In that case, make sure you plug the "dongle" part into your computer as well while you have AP manager open to see if there are any firmware updates for that.
Ok late reply but no I have the older version rectangular one. But I have all the parts that came with it and everything and I will be doing this when I get home. Once again thanks !
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