Welcome to the North American Subaru Impreza Owners Club Thursday July 31, 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 04-30-2005, 11:11 AM   #1
wrex03
Scooby Specialist
 
Member#: 29963
Join Date: Nov 2002
Location: chicago
Vehicle:
04 sti
silver

Default How to get rid of shift knock.

How do you get rid of shift Knock? I'll post a log either today, or monday.

The only way I'm not getting any is if I gradually release on the gas before a shift. If I just let of and shift, I get knock during very aggressive driving.
* Registered users of the site do not see these ads.
wrex03 is offline   Reply With Quote
Old 04-30-2005, 12:59 PM   #2
codean
Scooby Specialist
 
Member#: 10186
Join Date: Sep 2001
Chapter/Region: MWSOC
Location: some kind of bmw tech...
Default

Slip the clutch into the next gear, don't just drop the clutch. Also get all of the STI group N mounts for your car.
codean is offline   Reply With Quote
Old 04-30-2005, 01:20 PM   #3
LatentWagen
Scooby Guru
 
Member#: 50315
Join Date: Dec 2003
Chapter/Region: Tri-State
Location: New York
Vehicle:
0508 Saabaru & specB
Stage: Maintenance

Default

Quote:
Originally Posted by codean
Slip the clutch into the next gear, don't just drop the clutch. Also get all of the STI group N mounts for your car.
you could do that.......

or just add a little fuel in the 0% TPS column
LatentWagen is offline   Reply With Quote
Old 04-30-2005, 01:50 PM   #4
happasaiyan
Scooby Specialist
 
Member#: 37731
Join Date: Jun 2003
Chapter/Region: MWSOC
Location: Rolling Meadows, IL
Vehicle:
'07 TL-S 6MT
'07 RDX-T

Default

check out the timing in the 0 column...
Code:
Timing Map
   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]
   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]     [14]     [13]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [22]     [19]     [16]   [14.5]   [13.5]     [13]     [13]     [13]
   [-100]   [-100]     [33]     [23]     [19]     [16]     [15]     [14]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [23]     [19]   [16.5]     [16]   [14.5]     [13]     [13]     [13]
   [-100]   [-100]     [32]     [23]   [19.5]     [17]     [16]   [14.5]   [13.5]   [13.5]   [13.5]
   [-100]   [-100]     [31]     [23]     [20]   [17.5]     [16]     [15]     [14]     [14]     [14]
   [-100]   [-100]     [31]     [23]   [20.5]     [18]   [16.5]     [15]     [14]     [14]     [14]
   [-100]   [-100]     [30]     [23]     [21]   [18.5]   [16.5]     [15]     [14]     [14]     [14]
   [-100]   [-100]     [30]     [24]     [22]   [18.5]   [16.5]   [15.5]   [14.5]   [14.5]   [14.5]
   [-100]   [-100]     [29]     [24]     [22]     [19]     [17]   [15.5]   [14.5]   [14.5]   [14.5]
   [-100]   [-100]     [27]     [24]     [22]     [19]   [17.5]     [16]     [15]     [15]     [15]
     [19]     [19]     [25]     [24]     [22]     [19]     [18]   [16.5]   [15.5]   [15.5]   [15.5]
     [19]     [19]     [19]     [23]     [22]   [19.5]   [18.5]     [17]     [16]     [16]     [16]
     [19]     [19]     [19]     [22]     [22]   [19.5]   [18.5]   [17.5]   [16.5]   [16.5]   [16.5]
     [19]     [19]     [19]     [22]     [22]     [20]     [19]     [18]     [17]     [17]     [17]
     [20]     [20]     [20]     [22]     [22]     [21]     [20]     [19]     [18]     [18]     [18]
     [21]     [21]     [21]     [22]     [22]     [22]     [21]     [20]     [19]     [19]     [19]
     [21]     [21]     [21]     [22]     [22]     [22]     [21]     [20]     [19]     [19]     [19]
     [21]     [21]     [21]     [22]     [22]     [22]     [21]     [20]     [19]     [19]     [19]
     [21]     [21]     [21]     [22]     [22]     [22]     [21]     [20]     [19]     [19]     [19]
     [21]     [21]     [21]     [22]     [22]     [22]     [21]     [20]     [19]     [19]     [19]
     [21]     [21]     [21]     [22]     [22]     [22]     [21]     [20]     [19]     [19]     [19]
     [21]     [21]     [21]     [22]     [22]     [22]     [21]     [20]     [19]     [19]     [19]
     [21]     [21]     [21]     [22]     [22]     [22]     [21]     [20]     [19]     [19]     [19]
     [21]     [21]     [21]     [22]     [22]     [22]     [21]     [20]     [19]     [19]     [19]
   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]
   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]
   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]   [-100]
happasaiyan is offline   Reply With Quote
Old 04-30-2005, 01:59 PM   #5
MMBOOST
Scooby Specialist
 
Member#: 24140
Join Date: Sep 2002
Location: SFBA
Vehicle:
02 Impreza WRX
http://www.logmapper.com

Default

The proper way to get rid of shift knock is to put aroun 18 deg adv from around 4500 to redline in the 0 column. Its not a fueling problem, and here's why that's the case nd why the timing solution works:

You are going balls out, in the 90% or 100% column, revs are way up and you're pushing about 20+ degrees timing at around 7000 rpm, and then you shift. In an instant boost turns into vacuum and the UTEC moves into the 0% load column. So, in an instant you go from balls out timing to the timing that you have in there now or that the ECU provides (if you've letf it at 0). The problem is that this shift in timing is a drastic change in timing. This usually does, produce knock.

If you recall the "rule" that when you modify timing values you're support to interpolate the loadsites around it so that transitions in timing between loadsite are smooth, this is the same principle. The difference is, instead of a linear climb in load and RPMs, you're "wrapping around" from the 90/%100% to the 0% column via a

[edit] I just saw the map that was posted before I was able to finish my post. I should point out that he's running more than the 18 degress that I recommend... I didn't mean 18 has a hard and fast rule. It has to be commensurate with the timing you are running up top. You just want it to be close... and not just to the high load numbers but to the number in yoru 10% column too. Its tricky, soetimes. Although I think it needs to more similar to 10%-30% load columns at RPM ranges 1000-3000 RPM lower becaue after you shift and get back on the throttle, that's where you'll be ~4750@20%.[/edit]
MMBOOST is offline   Reply With Quote
Old 04-30-2005, 02:50 PM   #6
hippy
Scooby Specialist
 
Member#: 36528
Join Date: May 2003
Location: florida
Vehicle:
2002 Impreza Wrx
Silver

Default

Hey happ, your lower load columns at higher rpms look to me like they have abnormally retarded timing in them. Ie- as far as I know, there's no reason to have more retarded timing in the 0-20% columns compared to any of the higher columns at the same rpm ranges. Ya might wanna just copy the 30% load column over to the 0-20 where the values in the 0-20 are lower then the 30.

peace
hippy is offline   Reply With Quote
Old 04-30-2005, 03:47 PM   #7
LatentWagen
Scooby Guru
 
Member#: 50315
Join Date: Dec 2003
Chapter/Region: Tri-State
Location: New York
Vehicle:
0508 Saabaru & specB
Stage: Maintenance

Default

Quote:
Originally Posted by MMBOOST
The proper way to get rid of shift knock is to put aroun 18 deg adv from around 4500 to redline in the 0 column. Its not a fueling problem, and here's why that's the case nd why the timing solution works:

...
interesting... i was told that it could be fixed with a little fuel (.5 or so) in the 0 column. that, and it completely fixed my shift knock
LatentWagen is offline   Reply With Quote
Old 04-30-2005, 04:46 PM   #8
wrex03
Scooby Specialist
 
Member#: 29963
Join Date: Nov 2002
Location: chicago
Vehicle:
04 sti
silver

Default

Quote:
Originally Posted by MMBOOST
The proper way to get rid of shift knock is to put aroun 18 deg adv from around 4500 to redline in the 0 column. Its not a fueling problem, and here's why that's the case nd why the timing solution works:

You are going balls out, in the 90% or 100% column, revs are way up and you're pushing about 20+ degrees timing at around 7000 rpm, and then you shift. In an instant boost turns into vacuum and the UTEC moves into the 0% load column. So, in an instant you go from balls out timing to the timing that you have in there now or that the ECU provides (if you've letf it at 0). The problem is that this shift in timing is a drastic change in timing. This usually does, produce knock.

If you recall the "rule" that when you modify timing values you're support to interpolate the loadsites around it so that transitions in timing between loadsite are smooth, this is the same principle. The difference is, instead of a linear climb in load and RPMs, you're "wrapping around" from the 90/%100% to the 0% column via a

[edit] I just saw the map that was posted before I was able to finish my post. I should point out that he's running more than the 18 degress that I recommend... I didn't mean 18 has a hard and fast rule. It has to be commensurate with the timing you are running up top. You just want it to be close... and not just to the high load numbers but to the number in yoru 10% column too. Its tricky, soetimes. Although I think it needs to more similar to 10%-30% load columns at RPM ranges 1000-3000 RPM lower becaue after you shift and get back on the throttle, that's where you'll be ~4750@20%.[/edit]
Right after I posted I tried exactly what you stated, but I did 19 as that seemed to match up to the next load site after a shift.
wrex03 is offline   Reply With Quote
Old 04-30-2005, 05:10 PM   #9
RiftsWRX
Scooby Guru
 
Member#: 6124
Join Date: Apr 2001
Chapter/Region: MWSOC
Location: Glendale Hts, IL, USA
Vehicle:
2000 NFR AP1 S2000
'07 Honda FIT sport (5MT)

Default

Quote:
Originally Posted by wrex03
Right after I posted I tried exactly what you stated, but I did 19 as that seemed to match up to the next load site after a shift.
I'll make it easier dave, post a log of the knock and I'll tell you exactly what to do heh

Jorge (RiftsWRX)
www.ProjectWRX.com
RiftsWRX is offline   Reply With Quote
Old 04-30-2005, 08:01 PM   #10
happasaiyan
Scooby Specialist
 
Member#: 37731
Join Date: Jun 2003
Chapter/Region: MWSOC
Location: Rolling Meadows, IL
Vehicle:
'07 TL-S 6MT
'07 RDX-T

Default

Quote:
Originally Posted by hippy
Hey happ, your lower load columns at higher rpms look to me like they have abnormally retarded timing in them. Ie- as far as I know, there's no reason to have more retarded timing in the 0-20% columns compared to any of the higher columns at the same rpm ranges. Ya might wanna just copy the 30% load column over to the 0-20 where the values in the 0-20 are lower then the 30.

peace
no arguments here. i never hit those load sites (lower load, high rpm), so i never bothered to optimize them...so i just matched them to the 0 load column just in case it hit those load sites on the way down (to avoid shift knock). probably doesnt, but since i never hit those load sites, i didnt really care. thanks for looking out, though
happasaiyan is offline   Reply With Quote
Old 04-30-2005, 10:12 PM   #11
MMBOOST
Scooby Specialist
 
Member#: 24140
Join Date: Sep 2002
Location: SFBA
Vehicle:
02 Impreza WRX
http://www.logmapper.com

Default

happ,

you wont hit shift knock there. If you're not robbing yourself of power, at best you're preventing what I affectionally call "mash knock". (I.e. knock that happens right after you mash on the throttle after a shift, after you'd be expecting shift knock to occur. I'm sure hippy's right though.

jason
MMBOOST is offline   Reply With Quote
Old 04-30-2005, 10:36 PM   #12
LatentWagen
Scooby Guru
 
Member#: 50315
Join Date: Dec 2003
Chapter/Region: Tri-State
Location: New York
Vehicle:
0508 Saabaru & specB
Stage: Maintenance

Default

yea, whats the deal with mash knock. in second gear it happens often, and really slows me down.
LatentWagen is offline   Reply With Quote
Old 04-30-2005, 10:54 PM   #13
MMBOOST
Scooby Specialist
 
Member#: 24140
Join Date: Sep 2002
Location: SFBA
Vehicle:
02 Impreza WRX
http://www.logmapper.com

Default

You can think of mash knock as regular ol' WOT knock that happens down load. Its generally toomuch knock at low-boost@low-rpm loadsites. Look on WRXhackers.com. There's a lot of stuff about mash knock on there.
MMBOOST is offline   Reply With Quote
Old 05-01-2005, 07:40 PM   #14
MattSTi
Scooby Specialist
 
Member#: 54885
Join Date: Feb 2004
Chapter/Region: MAIC
Location: NYC/WV
Vehicle:
2004 PSM STi
2006 Mazda MX-5 Race Car

Default

I added 18 degrees in my 0% column after experiencing shift knock, cured it right away.

-matt
MattSTi 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
Dogs getting harassed by birds in backyard. How to get rid of birds? MyOtherRideIsUrMom Off-Topic 85 06-11-2010 12:46 AM
How to get rid of random/intermittent knock? Phatron Commercial ECU Reflashes 18 11-19-2007 05:53 PM
how to get rid of haze on the inside of a windsheild!??!? shipjumper Off-Topic 61 09-27-2005 07:42 AM
Do the 2005s get boost creep? If so, how to get rid of it? Optimus Prime Factory 2.5L Turbo Powertrain 14 09-09-2004 07:13 PM
('93-'01) pms!!! okay i need to know how to get rid of these. bratmantlz Impreza Forum 36 10-26-2001 09:50 PM


All times are GMT -4. The time now is 12:01 AM.


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.