The Subaru SVX World Network   SVX Network Forums
Live Chat!
SVX or Subaru Links
Old Lockers
Photo Post
How-To Documents
Message Archive
SVX Shop Search
IRC users:

Go Back   The Subaru SVX World Network > SVX Main Forums > Technical Q & A

Reply
 
Thread Tools Display Modes
  #1  
Old 05-02-2003, 09:45 AM
svxfiles's Avatar
svxfiles svxfiles is offline
There's a storm coming.
 
Join Date: Dec 2001
Location: Wiley Ford WV
Posts: 8,650
Significant Technical Input Registered SVX
timing advance

i have been told, that the timing can be advanced 8 degrees more than the stock 20 degrees, using the subaru select moniter. i have called two subaru mechanics, and one svx expert at SOA , plus a teacher of mechanics at a subaru training center, but none of them know how. can anyone here advise me?

thank's
Reply With Quote
  #2  
Old 05-02-2003, 10:01 AM
Porter
Guest
 
Posts: n/a
I know, I know!!

It involves a rain dance and sacrificing a chicken on top of the intake manifold.


I know the exact procedure, but if I told you I'd have to kill you, as it is top secret voodoo.








Haha j/k... I have no idea. LOL
Reply With Quote
  #3  
Old 05-02-2003, 11:54 AM
SVX10's Avatar
SVX10 SVX10 is offline
Fighting with electricity
 
Join Date: Mar 2001
Location: Tempe, AZ
Posts: 1,204
Send a message via AIM to SVX10 Send a message via Yahoo to SVX10
Wouldn't timing advance involve physically altering the angle of the camshaft without changing the angle of the crankshaft? Isn't that what adjustable cams are for. Now, spark/ignition advance would be computer controlled. Am I right? Hey, ob_au....what's the deal with this?
__________________
Time for my very own long list of mods:
92 SVX LS-L - Ebony Pearl - 2002 WRX 5MT trans w/STi gearset (rebuilt & installed myself ) - BMW E46 HID retrofit - Kenwood Headunit - Phoenix Gold 75x4 RMS amp - Alpine Type R 6.5" front components - Alpine Type R 6x9 3way rear speakers - 18"x9" Rota G-Force wheels w/225/40ZR18 Toyo T1R's - Mychailo's custom springs - Urethane front & rear sway bar bushings - KC exhaust (2.5" dual magnaflow) - Escaine seat swap - Removed Spoiler

I don't care if Subaru says it's STI...it will always be STi to me
Reply With Quote
  #4  
Old 05-02-2003, 12:33 PM
Porter
Guest
 
Posts: n/a
He's referring to the ignition timing. It's totally controlled by the ECU, as the car has distributorless electronic ignition.
Reply With Quote
  #5  
Old 05-02-2003, 01:32 PM
highpockets
Guest
 
Posts: n/a
Yes,But ,the ECU controls ignition firing or timing along with injector firing based on crank/cam sensor inputs so maybe you could modify or advance the sensor or trigger wheel. Tried this on a friends LHS chrysler for the hell of it and it wont even start,Scanner shows cam synch error and will not fire ignition. All depends on the program and tolerances I guess. Seems I read somewhere that advancing the cams on this engine disturbs the combustion efficiency or for lack of a better word,Factory engineered tuned runner volume that was a design characteristic of the Long intake and small ehxaust .Maybe someone with more technical knowledge could chime in !
Reply With Quote
  #6  
Old 05-02-2003, 04:32 PM
longassname's Avatar
longassname longassname is offline
Just some dude.
 
Join Date: Sep 2002
Location: Miami, FL
Posts: 3,986
Significant Technical Input
SVX's have 10.5:1 compression. Why would you possibly want to advance your timing more? You can barely run the car on premium as it is. Furthermore...........subaru computers are for lack of a better term "bad ass." They actively seek knock. Subaru computers continuously monitor the knock sensor and advance the timing up until the knock sensor gets the first hints of knock. So don't worry, our cars are already running with their timing advanced all the way to the edge, there's nothing left to be gotten there.
Reply With Quote
  #7  
Old 05-03-2003, 08:25 AM
immortal_suby's Avatar
immortal_suby immortal_suby is offline
Thread Killah
Alcyone Gold Contributor
 
Join Date: Feb 2001
Location: Greenville, SC
Posts: 5,835
Registered SVX
I used to advance the timing on the little red wagon up to 24btdc - stock was also 20. It required premium but did not knock even at 24 and it was defninitely more powerful - evidenced by a great increase in top speed.
The local suby tech - before he was evicted- told me he had his legacy sedan "altered" using only the select monitor to be way faster than the svx. He said there is a ton of potential in the engine that is untapped. If only we had a curious master tech with an svx that could expreiment.

Why not set the ECU up to be able to advance the timing even more - like you said the watchdogs are in there to reign it in if it's to much.
__________________
Matt
Locker Link
2015 BRZ Limited 6MT
92 Ebony LS-L ECUtune Stage2av1, Z32 MAF, 370cc injectors, TomsSVX intake, BontragerWorks 22mm RSB #003, HID Hi and Lo beams, OT endlink and bushing mods, PWR Aluminum radiator, Harvey's QC shift kit, 2.5" flowmaster 80 exhaust, 17" Michelin Pilot Sport A/S, Poly sway bar bushings, Slotted Bradi rotors, AFBeefcake powdercoated calipers, 97 grill, and a huge set of air horns. 300,000 miles and counting
92 Ebony LS-L. ecutune stage1v4, motorsport 1pc pulley. Garage Queen - sold to Dad in upstate NY 155,000 miles
19 Subaru Ascent Premium - -Hers !.
89 DL 4x4 little red wagon - a.k.a. The immortal suby. 275k R.I.P.
Reply With Quote
  #8  
Old 05-03-2003, 08:41 AM
NomadTW's Avatar
NomadTW NomadTW is offline
abrasive personality
 
Join Date: Apr 2002
Location: Mars, PA
Posts: 1,199
Send a message via AIM to NomadTW
you could get an ignition computer... but that's not just using the select mon

i have no problems running the car on 93, and the ppl in calif run on 91 or lower, so i think that 93 should be fine w/ some advance

and my guess as to what it does with the advancing in conjunction to subaru's knock computer, is right now the ecu will advance it continually until it senses knock, OR it reaches 20 deg advance, whichever comes first, so if you give it an extra 6 degrees to go to sense knock you'll get more power
__________________
SV What?
Reply With Quote
  #9  
Old 05-03-2003, 11:04 AM
longassname's Avatar
longassname longassname is offline
Just some dude.
 
Join Date: Sep 2002
Location: Miami, FL
Posts: 3,986
Significant Technical Input
Actually the 20 degress is the base timing. The ecu then uses a factory created 3d table to determine how much to advance the timing from there according to engine rpm and load. It then advances it a lil more until it senses knock so that it runs on the very edge.

As for reprogramming the base timing in the computer via the select monitor I'd love to hear that that is possible but i highly doubt it. I wouldn't advance the base timing but that would indicate the computer was flashable. That is how it is done on the newer subaru computers; however, subaru has offered a program change for the svx once before and it was installed via an eprom chip (this was to address issues caused by lower octane fuel in i believe 92 and 93 cars). Eprom's were the standard at the time of svx manufacture. It's an Erasable Programable Read Only Memory chip which must be removed, erased with uv light, and then reprogrammed with a programmer in order to change the program (code, constants, table values). I've considered examing the svx ecu to determine the processor so i could look up it's opcodes and what memory configurations it is available in and if there is an assembler/dissambler program available for it but as of yet I haven't done that.
Reply With Quote
  #10  
Old 05-03-2003, 11:08 AM
longassname's Avatar
longassname longassname is offline
Just some dude.
 
Join Date: Sep 2002
Location: Miami, FL
Posts: 3,986
Significant Technical Input
Oh, now that you guys have me thinking about the svx ecu again...........if anyone has a select monitor i'd love to get the chance to use it and log the datastream between it and the ecu. That's by far the easiest way to start labeling program loops and tables even after dissambling the program.
Reply With Quote
  #11  
Old 05-03-2003, 02:52 PM
svxfiles's Avatar
svxfiles svxfiles is offline
There's a storm coming.
 
Join Date: Dec 2001
Location: Wiley Ford WV
Posts: 8,650
Significant Technical Input Registered SVX
timing advance

thanks for the input. on page 3 of section 2.2 of the factory service manual, it says,"ignition timing [BTDC/rpm]:20º ± 8°/610"

OK then, what i understand about this is, up untill detonation, the more advance the better so that the flame has time to burn the air gas mixture and has its maximum pressure at tdc. in comparison to other engines the subarus have a very conservitive timing map. on my 92 , with the newly installed headers, the select moniter shows a timing retard of up to 10 degrees, the timing advance goes up to 50 advance. when i tip in on the throttle, the timing retards, possibly due to the slightly louder exhaust, causing the spaek knock sensors to react.
when the timing retards the engine goes off song, and power drops off as well. i know i can insulate the 2 knock sensors, but that takes away a very good safeguard.
Reply With Quote
  #12  
Old 05-03-2003, 08:56 PM
longassname's Avatar
longassname longassname is offline
Just some dude.
 
Join Date: Sep 2002
Location: Miami, FL
Posts: 3,986
Significant Technical Input
Re: timing advance

Quote:
Originally posted by svxfiles
thanks for the input. on page 3 of section 2.2 of the factory service manual, it says,"ignition timing [BTDC/rpm]:20º ± 8°/610"

OK then, what i understand about this is, up untill detonation, the more advance the better so that the flame has time to burn the air gas mixture and has its maximum pressure at tdc. in comparison to other engines the subarus have a very conservitive timing map. on my 92 , with the newly installed headers, the select moniter shows a timing retard of up to 10 degrees, the timing advance goes up to 50 advance. when i tip in on the throttle, the timing retards, possibly due to the slightly louder exhaust, causing the spaek knock sensors to react.
when the timing retards the engine goes off song, and power drops off as well. i know i can insulate the 2 knock sensors, but that takes away a very good safeguard.
I don't know about svx's in particular but you could be right about some change you made to the exhaust getting picked up by the knock sensor. I know with chevy rebuilds often forged pistons will trip the factory knock sensor. I don't really know what to do about it.
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


All times are GMT -6. The time now is 06:14 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
© 2001-2015 SVX World Network
(208)-906-1122