Where do you guys set your base ignition timing (L98)?
08-14-2005, 09:14 PM
#1
Drifting
Thread Starter
Where do you guys set your base ignition timing (L98)?
Hi guys,
I set the timing to the stock setting on my '89 yesterday (6degBTC), and I got to thinking what would happen if I where to advance it a little. But seeing as the ECM controls the timing anyway, would advancing the base setting have any real effect? If it does, what do you guys like to set the base ignition timing to on your cars (especially L98s)?
Thanks in advance.
I set the timing to the stock setting on my '89 yesterday (6degBTC), and I got to thinking what would happen if I where to advance it a little. But seeing as the ECM controls the timing anyway, would advancing the base setting have any real effect? If it does, what do you guys like to set the base ignition timing to on your cars (especially L98s)?
Thanks in advance.
08-14-2005, 10:14 PM
#3
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St. Jude Donor '05
You can do this.
The only problem is globally advances the timing. Your car may be able take 4-6-8... more degrees in some areas and only 2-3 in others. In some cases I found the vettes to run better at higher RPM with less timing that the factory puts in them. But that doesn't mean at lower RPM it couldn't take anthor 6.. etc.
But this can only be done threw a chip.
The only problem is globally advances the timing. Your car may be able take 4-6-8... more degrees in some areas and only 2-3 in others. In some cases I found the vettes to run better at higher RPM with less timing that the factory puts in them. But that doesn't mean at lower RPM it couldn't take anthor 6.. etc.
But this can only be done threw a chip.
08-14-2005, 10:28 PM
#4
In an L98, the ECM increases the timing 14* from whatever your base setting is, and the ESC and EST will retard it to as low as your base setting if it detects knock. So yes, increasing base timing will help...
When I bought my vette, the timing was set to 8 degrees retarded...
Bumped it up to 0* to see if there was a pinging problem (there was)
I fixed the pinging problem, so now I'll bump it up to 6* or 8* and repeat the process...
I know jumping up 8* made a huge difference, I'm hoping the next 8* will be a similar jump in performance.
When I bought my vette, the timing was set to 8 degrees retarded...
Bumped it up to 0* to see if there was a pinging problem (there was)
I fixed the pinging problem, so now I'll bump it up to 6* or 8* and repeat the process...
I know jumping up 8* made a huge difference, I'm hoping the next 8* will be a similar jump in performance.
Last edited by mikey whipreck; 08-14-2005 at 10:31 PM.
08-14-2005, 11:44 PM
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I leave it set at 8*
08-15-2005, 01:08 AM
#6
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St. Jude Donor '05
Originally Posted by mikey whipreck
In an L98, the ECM increases the timing 14* from whatever your base setting is, and the ESC and EST will retard it to as low as your base setting if it detects knock. So yes, increasing base timing will help...
When I bought my vette, the timing was set to 8 degrees retarded...
Bumped it up to 0* to see if there was a pinging problem (there was)
I fixed the pinging problem, so now I'll bump it up to 6* or 8* and repeat the process...
I know jumping up 8* made a huge difference, I'm hoping the next 8* will be a similar jump in performance.
When I bought my vette, the timing was set to 8 degrees retarded...
Bumped it up to 0* to see if there was a pinging problem (there was)
I fixed the pinging problem, so now I'll bump it up to 6* or 8* and repeat the process...
I know jumping up 8* made a huge difference, I'm hoping the next 8* will be a similar jump in performance.
08-15-2005, 11:28 AM
#9
Originally Posted by Alvin
Its true the knock sensor will do quite a bit to keep the car from knocking but the problem lies in the fact that the knocksensor WILL over correct and put timing back in slowly. so not only did it pull too much out, its still hurting you 1000rpm down the road. On top of that if it hears knock on a regular occasion it will go in a "low octane mode" (most models) which is basically back where you started from.
08-15-2005, 02:00 PM
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Originally Posted by CFI-EFI
Mine is set at 14° BTDC.
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08-15-2005, 02:15 PM
#11
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St. Jude Donor '05
Originally Posted by mikey whipreck
That is if you still have you're knock sensor connected
Your right, if you have the knock sensor disconnected it goes ahead and pulls timing automatically to keep you safe.. Its a lose/lose situation
08-15-2005, 08:18 PM
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Originally Posted by k0rv3tt389
14° BTDC and no pinging? You must be using super unleaded gasoline all the time!! I personally would wanna keep mine at max 8° so I can use regular grade gas. $2.60 for regular here eats big holes in my wallet.
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08-15-2005, 08:22 PM
#13
Drifting
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Originally Posted by CFI-EFI
85 Octane. It is "super unleaded gasoline" alright. Super cheap (comparatively). If you can tell me of something cheaper, I'll try it.
That's pretty amazing! Has anyone else tried anything like this?
08-15-2005, 08:23 PM
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Originally Posted by CFI-EFI
85 Octane. It is "super unleaded gasoline" alright. Super cheap (comparatively). If you can tell me of something cheaper, I'll try it.
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Damn, that's a pretty low octane rating. Because mine is a TPI and yours in a Cross-Fire, would it make a moderate difference if I also set my base timing @ 14 degrees BTDC?? I see my stock c/r is 9.5:1
08-15-2005, 08:32 PM
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Originally Posted by Alvin
Your right, if you have the knock sensor disconnected it goes ahead and pulls timing automatically to keep you safe.. Its a lose/lose situation
"Electronic spark control is accomplished with a module that sends a voltage signal to the ECM. As the knock sensor detects engine knock, the voltage from the ESC module to the ECM is shut off and this signals the ECM to retard the timing."
Based on this, no signal from the knock sensor, means no interruption of the voltage from the ESC to the ECM. Therefore, no cause for the ECM to retard the timing.
I would agree that unplugging the ESC would cause the timing to remain permanently retarded, but not with only the knock sensor disconnected. My knock sensor has been disconnected for years. It runs too well for the timing to be messed up.
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08-15-2005, 08:45 PM
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Originally Posted by TheCorvetteKid
Wait a minute, wait a minute...you're running 85 octane with a 14deg ignition advance, and you're NOT getting any pinging?!?
Originally Posted by k0rv3tt389
Damn, that's a pretty low octane rating. Because mine is a TPI and yours in a Cross-Fire, would it make a moderate difference if I also set my base timing @ 14 degrees BTDC?? I see my stock c/r is 9.5:1
08-15-2005, 11:29 PM
#18
Originally Posted by CFI-EFI
Not according to MY Helms:
"Electronic spark control is accomplished with a module that sends a voltage signal to the ECM. As the knock sensor detects engine knock, the voltage from the ESC module to the ECM is shut off and this signals the ECM to retard the timing."
Based on this, no signal from the knock sensor, means no interruption of the voltage from the ESC to the ECM. Therefore, no cause for the ECM to retard the timing.
I would agree that unplugging the ESC would cause the timing to remain permanently retarded, but not with only the knock sensor disconnected. My knock sensor has been disconnected for years. It runs too well for the timing to be messed up.
RACE ON!!!
"Electronic spark control is accomplished with a module that sends a voltage signal to the ECM. As the knock sensor detects engine knock, the voltage from the ESC module to the ECM is shut off and this signals the ECM to retard the timing."
Based on this, no signal from the knock sensor, means no interruption of the voltage from the ESC to the ECM. Therefore, no cause for the ECM to retard the timing.
I would agree that unplugging the ESC would cause the timing to remain permanently retarded, but not with only the knock sensor disconnected. My knock sensor has been disconnected for years. It runs too well for the timing to be messed up.
RACE ON!!!
Helms is awesome isn't it? It has helped me vastly in understanding the ESC system... I've read and reread it trying to understand where my Code 43 comes from.
08-15-2005, 11:31 PM
#19
Originally Posted by Z51L9889
I run 10 BTDC base timing. I have gone as high as 12 degrees in the past, but it would knock occasionally under high load in 4th, so I backed it off a touch.
Last edited by mikey whipreck; 08-15-2005 at 11:34 PM.
08-16-2005, 12:33 AM
#20
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St. Jude Donor '05
Originally Posted by mikey whipreck
Thank you for backing me up on that. I would think that a 'supporting tuner' would better understand how this system works.
Helms is awesome isn't it? It has helped me vastly in understanding the ESC system... I've read and reread it trying to understand where my Code 43 comes from.
Helms is awesome isn't it? It has helped me vastly in understanding the ESC system... I've read and reread it trying to understand where my Code 43 comes from.
Excuse me? Yeah, I guess I have no idea what i'm talking about..
Nor does Tjwong
http://forums.corvetteforum.com/show...ck&forum_id=48
Nor does any of the license GM service manuals I have
Unplugging the knock sensor, which will cause a DTC 43 will result in the ECM pulling a Default amount of timing.
Do you really think GM will just ignore a knock sensor code being thrown? Do you really think the computer will just keep on its mary way with no action?