Welcome to the North American Subaru Impreza Owners Club Monday June 1, 2020
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Engine Management & Tuning > Open Source Reflashes

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 09-30-2011, 05:27 PM   #1
dux10
Scooby Specialist
 
Member#: 235338
Join Date: Jan 2010
Chapter/Region: South East
Location: Georgia
Vehicle:
2002 Faggin Wagon
srp

Default Timing: when is too much?

So I've just gotten into tuning fairly heavily lately and I keep worrying that I'm gonna end up running to much timing and grenade the motor. I know they (whoever "they is?) say to keep adding timing until you stop seeing gains or start seeing knock, and then drop a degree...
That's fine and dandy, but is there a general guidline as how much is considered safe and how much is considered aggressive? And what factors (outside of fuel type) tyically affect how much timing can be run? I understand "timing is not a knob for turning up the power: boost is." But obviously timing is also a major component in power production.
BTW: this is for 93 oct but I will take suggestions for 91 and E85 as well.


EXAMPLE: 2002 WRX
EJ205 130k miles
Turbo inlet
Blouch "small" 16G
3" tbe
Catless UP
FMIC lightweight crank pulley
GM ebcs
840cc injectors

I'm running ~21psi tappering down to 18.25 at redline with 11.4:1 AFR tapering to 11:1 at redline
Timing is 16.5/17* at peak tq and 24.5/25* at redline.
Never any knock, but I dont know if I should keep adding or leave it alone?
If needed I can post up logs later.
* Registered users of the site do not see these ads.

Last edited by dux10; 09-30-2011 at 05:39 PM.
dux10 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 10-02-2011, 01:33 AM   #2
D0nets
Scooby Newbie
 
Member#: 129746
Join Date: Oct 2006
Location: West TN
Vehicle:
2007 stg3 WRX
WR Blue

Default

It all depends on the motor, mods, afrs, boost, etc... A general rule of thumb is to start at 13 at peak tq and 20 at redline. If you dont see knock, keep adding until you see knock, then back off a degree or 2. Some people like running more timing and more fuel, some like less timing and less fuel.
D0nets is offline   Reply With Quote
Old 10-02-2011, 09:10 AM   #3
quazimoto
Scooby Guru
 
Member#: 70395
Join Date: Sep 2004
Chapter/Region: MAIC
Location: Da-boonies,Va
Default

/\ Like said above it's not a "black and white: has to be done this way" thing. Different ways you can do it.
quazimoto is offline   Reply With Quote
Old 10-02-2011, 11:01 AM   #4
TheBoz
Scooby Newbie
 
Member#: 64397
Join Date: Jun 2004
Chapter/Region: SCIC
Location: Corona, CA USA
Vehicle:
2006 WRX STI
Steel Gray

Default

91-93oct fuel will knock before MBT. So you can rely on your knock sensor to show you max timing before MBT. However you should be sure that your knock sensor is working before you push it to far. So if you numbers go way byond the norm consider putting in a new knock sensor.

On E85 you will never see knock at MBT. You can go way past MBT very easy on E85. I have seen people running 20* at peek TQ and 26-30* at peek rpm. On my car I am at 12* at peek torque and like 24-25. I know I can put more timing in the car at peek rpm however need to get on a dyno to check. So rule of thum with E85 peek TQ will require less timing than 91-93oct and peek RPM will require way more timing that 91-93oct. E85 also has a huge ramp rate, you could go 10-14* from peek tq to peek rpm.

Point of the story is use some good VDR software or take your car to a dyno, to ensure that you are making more power with every degree of timing. Once you stop making HP/TQ while adding timing you are at MBT and should back it off .5-1*.
TheBoz is offline   Reply With Quote
Old 10-02-2011, 11:04 AM   #5
TheBoz
Scooby Newbie
 
Member#: 64397
Join Date: Jun 2004
Chapter/Region: SCIC
Location: Corona, CA USA
Vehicle:
2006 WRX STI
Steel Gray

Default

Quote:
Originally Posted by D0nets View Post
It all depends on the motor, mods, afrs, boost, etc... A general rule of thumb is to start at 13 at peak tq and 20 at redline. If you dont see knock, keep adding until you see knock, then back off a degree or 2. Some people like running more timing and more fuel, some like less timing and less fuel.
Boost will make more power than timing. So I run a fatter AFR and more boost with happy timing.

Leaning on your afr is just opening the door for bad stuff to happen. I tune on the rich side so that I have a safty margin. I dont mind loosing 5-10whp for a much safer tune.
TheBoz is offline   Reply With Quote
Old 10-02-2011, 09:32 PM   #6
eminehart
Scooby Newbie
 
Member#: 11205
Join Date: Oct 2001
Chapter/Region: NWIC
Location: Tweakin your ECU-Portlandia
Vehicle:
2015 WRX
WRB

Default

I have seen cases where a car with 11.7 AFR made the same power at 11.0:1 with the extra timing. At 11.7 AFR the car would not take anymore timing.
The safe way to set up the tune is to run it rich with plenty of timing. Worse case scenario the ecu learns to pull timing if it see's knock. At 11.7 there is really no room for error. If the AFR leans out a bit with seasonal changes or with AF Learning D, there goes a ringland. The knock control system doesn't add fuel to the map to fix AFR issues, until it's too late in most situations.
eminehart is offline   Reply With Quote
Old 10-02-2011, 09:39 PM   #7
codesoccer
Scooby Specialist
 
Member#: 179573
Join Date: May 2008
Chapter/Region: South East
Location: South Florida
Vehicle:
2002 MBP Bugeye
Flip Flop Tuned on corn

Default

Quote:
Originally Posted by eminehart View Post
If the AFR leans out a bit with seasonal changes or with AF Learning D, there goes a ringland.
I've seen people change the value of the AF learning D to 80+ grams to help avoid something like that.
codesoccer is offline   Reply With Quote
Old 10-02-2011, 10:39 PM   #8
dux10
Scooby Specialist
 
Member#: 235338
Join Date: Jan 2010
Chapter/Region: South East
Location: Georgia
Vehicle:
2002 Faggin Wagon
srp

Default

Quote:
Originally Posted by TheBoz View Post
91-93oct fuel will knock before MBT. So you can rely on your knock sensor to show you max timing before MBT. However you should be sure that your knock sensor is working before you push it to far. So if you numbers go way byond the norm consider putting in a new knock sensor.

On E85 you will never see knock at MBT. You can go way past MBT very easy on E85. I have seen people running 20* at peek TQ and 26-30* at peek rpm. On my car I am at 12* at peek torque and like 24-25. I know I can put more timing in the car at peek rpm however need to get on a dyno to check. So rule of thum with E85 peek TQ will require less timing than 91-93oct and peek RPM will require way more timing that 91-93oct. E85 also has a huge ramp rate, you could go 10-14* from peek tq to peek rpm.

Point of the story is use some good VDR software or take your car to a dyno, to ensure that you are making more power with every degree of timing. Once you stop making HP/TQ while adding timing you are at MBT and should back it off .5-1*.

why is this? I'm sure there's a logical explanation but I fail to see it.
On a side note I may try dropping 2 degrees and upping the boost another pound. My problem now is its started getting fairly cool here and I may not have a chance to test the reliability of it in warmer weather until spring....
dux10 is offline   Reply With Quote
Old 10-08-2011, 01:57 AM   #9
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

Quote:
Originally Posted by eminehart View Post
I have seen cases where a car with 11.7 AFR made the same power at 11.0:1 with the extra timing. At 11.7 AFR the car would not take anymore timing.
The safe way to set up the tune is to run it rich with plenty of timing. Worse case scenario the ecu learns to pull timing if it see's knock. At 11.7 there is really no room for error. If the AFR leans out a bit with seasonal changes or with AF Learning D, there goes a ringland. The knock control system doesn't add fuel to the map to fix AFR issues, until it's too late in most situations.
What's safer - a car that runs 11.7 AFR with timing that's two degrees below the knock threshold, or a car that runs 11.0 with timing that's two degrees below the knock threshold?

Assume the same turbo, same IC, same motor (stock), same boost (reasonable for the turbo and IC), etc, etc. No the other variables.

My point here is that I don't think there is a difference in safety between those two tunes. Either one will knock with a couple extra degrees of timing, or with a few percent variation in AFR, because both are tuned to within the same "distance" from the knock threshold.

You could make the 11.7 tune safer by fattening it up to 11.0, but then you add more timing (due to the richer AFR), and the extra safety margin goes away, and you've got the same safety margin as before - just with a richer AFR and more ignition advance.

Those tunes would likely yield different power curves, but that's another story. I've been running my LGT at about 11:1 for a couple years, but 12:1 for a couple months (with lower timing, of course, so I'm still the same distance from the knock threshold). Dunno yet which tradeoff is more powerful but I suspect that's the 11:1 tune.

To the OP: my advice is to dial in your AFRs for a consistent 11:1, and tune up the boost slowly. More boost will require less timing. When you find that you're running around 11-13 at peak tq and 17-20 at redline, and 2 more degrees would induce knock, you've probably got a good tune.

You'd need a dyno, or a good place to do road dynos, to find the best tune for your setup... run a little more boost (reducing timing to compensate) or a little less (with more timing) or a richer AFR (more timing) or a leaner AFR (less timing).

You've basically got three knobs: boost, timing, AFR. You can tweak any one of them to get a little more power, but you'll have to make corresponding change to one or both of the others to get your margin of safety back. Once you reach a point where you're balancing those parameters and you know what your safety margin is (and like I said, I think it's reasonable to measure that margin in degrees-from-the-knock-threshold), then the big question is which combination gives you the most power.
NSFW is offline   Reply With Quote
Old 10-29-2011, 12:56 PM   #10
Azriel_Strife
Scooby Newbie
 
Member#: 299366
Join Date: Oct 2011
Chapter/Region: VIC
Location: Chilliwack BC, Canada
Vehicle:
2002 Impreza WRX
Blue

Default

I prefer to run less timing and make up for the power loss with additional boost pressure and fuel. Timing is what is going to cause knock and increased combustion chamber temps. A few degrees over stock won't hurt, but advanving timing to the ragged edge could be asking for trouble, especially if you get an ECU hiccup or the engine has higher mileage.

I have never tuned a subaru before, but from experience, pistons all react the same to knock and too much timing. Not saying what you shuld do, but I would make sure there is a decent safety margin between knock and your actual advance setting.
Azriel_Strife is offline   Reply With Quote
Old 10-30-2011, 10:06 AM   #11
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

Quote:
Originally Posted by Azriel_Strife View Post
I prefer to run less timing and make up for the power loss with additional boost pressure and fuel. Timing is what is going to cause knock and increased combustion chamber temps.
So after you finish your tune, going leaner won't cause it to knock?
NSFW is offline   Reply With Quote
Old 10-30-2011, 10:52 PM   #12
Azriel_Strife
Scooby Newbie
 
Member#: 299366
Join Date: Oct 2011
Chapter/Region: VIC
Location: Chilliwack BC, Canada
Vehicle:
2002 Impreza WRX
Blue

Default

Less fuel will cause more heat, wich in turn will cause knock, but over advanced timing is more likely to cause knock. If your fueling is at a safe level, adding more timing will increase the chance of knock.

Essentially what i was trying to say was what the others were saying (add timing till you see little to no effect on power, and then drop a couple degrees for safety.)
Azriel_Strife is offline   Reply With Quote
Old 11-02-2011, 09:27 AM   #13
bmx045
Scooby Newbie
 
Member#: 262684
Join Date: Nov 2010
Chapter/Region: NESIC
Location: Andover, MA
Vehicle:
2019 WRX Premium
ISM

Default

These EJ's are happy with rich AFR's (low 11's) and seemingly don't gain much by going leaner, the richness also plays well with knock supression to a degree... IMO the piece of mind of an AFR in the low 11's outweighs the minimal gains seen in a leaner AFR.
bmx045 is offline   Reply With Quote
Old 11-02-2011, 09:58 AM   #14
Bad Noodle
Scooby Specialist
 
Member#: 174442
Join Date: Mar 2008
Chapter/Region: Tri-State
Location: NNJ
Vehicle:
2007 SuperWagon
I don't spell well

Default

One thing I haven't seen mentioned yet is that running higher timing yields higher cylinder pressures. So if you're on a stock block, that might be a consideration.
Bad Noodle is offline   Reply With Quote
Old 11-02-2011, 01:41 PM   #15
Phatron
Scooby Guru
 
Member#: 36033
Join Date: Apr 2003
Chapter/Region: SCIC
Location: Tuning Lab
Vehicle:
CEO PhatBottiTuning
2006 STi GTX3582 + Meth

Default

Quote:
Originally Posted by TheBoz View Post
On E85 you will never see knock at MBT. You can go way past MBT very easy on E85.
this isnt true at all....and i can show you hundreds of logs of knock on e85.

Its mostly on 16bit ecu's....but i have plenty of logs of knock on 32bit ecus too.

Is it false knock? cant really tell you. if it was 1 or 2 cars i might say yes....but its not.

Its one of those "nasioc-isms" like "all you have to do for e85 tune is multiply the inj scalar by 0.7"....thats not true either.

Quote:
Originally Posted by NSFW View Post
What's safer - a car that runs 11.7 AFR with timing that's two degrees below the knock threshold, or a car that runs 11.0 with timing that's two degrees below the knock threshold?

Assume the same turbo, same IC, same motor (stock), same boost (reasonable for the turbo and IC), etc, etc. No the other variables.

My point here is that I don't think there is a difference in safety between those two tunes. Either one will knock with a couple extra degrees of timing, or with a few percent variation in AFR, because both are tuned to within the same "distance" from the knock threshold.

.
They arent the same.....you are discounting EGT's. The car at 11.7 will have EGT's 100-300* higher than the car at 11.0

So if the car at 11.7 gets a turbo inlet leak and leans out to 12.5-13.5...now the EGT's are most likely gonna melt something....

The car at 11.0 gets a turbo inlet leak and leans out to 11.8-12.8...now the EGT's are only up to the point of the 11.7 car without a leak.
Phatron is offline   Reply With Quote
Old 11-03-2011, 03:25 AM   #16
NSFW
Scooby Guru
 
Member#: 140444
Join Date: Feb 2007
Chapter/Region: NWIC
Location: Near Seattle, WA
Vehicle:
05 Stage Free LGT
ATP 3076, 6MT, AVO FMIC

Default

Quote:
Originally Posted by Phatron View Post
They arent the same.....you are discounting EGT's. The car at 11.7 will have EGT's 100-300* higher than the car at 11.0

So if the car at 11.7 gets a turbo inlet leak and leans out to 12.5-13.5...now the EGT's are most likely gonna melt something....

The car at 11.0 gets a turbo inlet leak and leans out to 11.8-12.8...now the EGT's are only up to the point of the 11.7 car without a leak.
Interesting. But wouldn't they both be knocking enough that EGTs would be the least of your concerns?

Incidentally, my AFRs actually went from 11:1 to 12:1 a couple months ago when my fuel pump started to crap out. But thankfully I had about 4 degrees pulled at the time, since I was tinkering with things.
NSFW is offline   Reply With Quote
Old 11-03-2011, 12:23 PM   #17
Phatron
Scooby Guru
 
Member#: 36033
Join Date: Apr 2003
Chapter/Region: SCIC
Location: Tuning Lab
Vehicle:
CEO PhatBottiTuning
2006 STi GTX3582 + Meth

Default

^ they may both be knocking, but the car thats leaner is going to be knocking worse and the EGT's are going to be higher.

Going lean doesnt automatically mean knock...but it almost always means the EGT's will rise significantly.

I look at tuning the AFR on a normal setup, just like i look at tuning the AFR on a meth kit with no safety features. Why run it at 12:1? you dont really pick up a crapload of power, all you're doing is destroying your safety net. A meth kit fails at 12:1 and the car runs 13:1.....or the meth kit fails at 11:1 and the car runs 12:1......it should be pretty obvious which way is the safest way to tune the car.
Phatron is offline   Reply With Quote
Old 04-08-2020, 12:32 PM   #18
contaminatrix
Scooby Newbie
 
Member#: 435611
Join Date: Dec 2015
Chapter/Region: International
Location: Nairobi
Vehicle:
2002 SG5-2.0-XT-JDM
45A, originally 18L

Default

necrobump

this is good reading.
contaminatrix 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
Oil, how much is too little, and how much is too much? lavid2002 Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo) 18 10-19-2010 11:40 PM
When too much is too much for a WRX Kings028 Newbies & FAQs 13 03-18-2010 02:38 PM
How much follow up is too much when trying to get a new job? Kiwi Off-Topic 10 03-20-2009 03:19 PM
When too much is too much, we can always look back at Frank Zane. Snoopy Off-Topic 7 09-28-2007 11:00 AM
When is too much caster too much? silver arrow Motorsports 15 11-06-2006 09:03 AM

All times are GMT -4. The time now is 07:45 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2020 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.