Want to tune DFCO and timing to blow flames during shift: 2000 C5
12-05-2017, 08:53 PM
#21
10 Second Club
iTrader: (12)
Join Date: May 2004
Location: Chicago IL/ Lake Geneva WI
Posts: 930
Likes: 0
Received 0 Likes
on
0 Posts
Now that we've gotten the insult portion of the evening over 
Would you like to help make some sweet BRAAAPS 
or continue arguing 
Either way is cool with me! Be careful, you might need some hip waders with all the POWER TUNING going on here on this most serious forum on the whole internet. 
12-05-2017, 09:02 PM
#22
TECH Senior Member
My my, SOMEONE got their panties in a wad! Can't take a little ribbing?? lol
12-05-2017, 09:25 PM
#24
TECH Senior Member
I can't SEE, no, no, no.
Naw, it's all good, man! Good to see we can all have a little fun!
Naw, it's all good, man! Good to see we can all have a little fun!
02-06-2018, 09:53 AM
#25
Glad you guys kissed and made up
Here's an update for anyone interested
From HPTuners board:
We aren't looking for a a visible flame under load, we are looking for a flame between shifts or on decel.
nsogiba, try running less timing, maybe 0 degree or even -5 degrees. Even on bone stock vehicles timing can go negative during TM events. Additionally, to the right of your highlighted point timing increases and then ramps down, you need to look at your timing tables and get it to hold the lower timing, not go from WOT timing to 5 degrees then back up to 20ish and slowly back down like it does in the log. Look at the idle spark tables, not just the main spark tables. Thanks for replying, I am still working through this.
Part of the issue what that graph was that I had Idle Timing tables that differed. Specifically, they didn't have much timing retard (if any), whereas the main spark tables did.
So I made some changes to retard timing above 3000 rpm at cylinder airmass values in the Idle tables (both in gear and in park, whatever that means since this is a 6 speed manual C5) to match - now I can get a really steady and angry crackle on decel. However, this only occurs with a tiny bit of throttle input on decel (don't recall exactly how much, but only a few % I'd say). I wonder if this has something to do with the "Tumble Flap Closed" values, which by the description decides when the PCM disables main spark tables (what does it start using then? Idle tables?)
My settings seem to have the main spark tables permanently disabled since I'll never go above 250 mph - but going above 1.2% will also do something - so I wonder if that overrides that max speed requirement. Is it one or the other, or must both values be satisfied to enable that effect? Also, does it use Idle Tables when it's not using main spark?
Finally, the last thing I'm looking for is to retard timing DURING a shift (only while No Lift Shifting using N2MB WOTBOX). Is there some sort of condition in which the g/cyl or cylinder airmass changes during a no-lift shift that I can take advantage of to fool the PCM into retarding timing?
I will work on posting up a log during some No lift shift events
Here's an update for anyone interested
From HPTuners board:
We aren't looking for a a visible flame under load, we are looking for a flame between shifts or on decel.
nsogiba, try running less timing, maybe 0 degree or even -5 degrees. Even on bone stock vehicles timing can go negative during TM events. Additionally, to the right of your highlighted point timing increases and then ramps down, you need to look at your timing tables and get it to hold the lower timing, not go from WOT timing to 5 degrees then back up to 20ish and slowly back down like it does in the log. Look at the idle spark tables, not just the main spark tables.
Part of the issue what that graph was that I had Idle Timing tables that differed. Specifically, they didn't have much timing retard (if any), whereas the main spark tables did.
So I made some changes to retard timing above 3000 rpm at cylinder airmass values in the Idle tables (both in gear and in park, whatever that means since this is a 6 speed manual C5) to match - now I can get a really steady and angry crackle on decel. However, this only occurs with a tiny bit of throttle input on decel (don't recall exactly how much, but only a few % I'd say). I wonder if this has something to do with the "Tumble Flap Closed" values, which by the description decides when the PCM disables main spark tables (what does it start using then? Idle tables?)
My settings seem to have the main spark tables permanently disabled since I'll never go above 250 mph - but going above 1.2% will also do something - so I wonder if that overrides that max speed requirement. Is it one or the other, or must both values be satisfied to enable that effect? Also, does it use Idle Tables when it's not using main spark?
Finally, the last thing I'm looking for is to retard timing DURING a shift (only while No Lift Shifting using N2MB WOTBOX). Is there some sort of condition in which the g/cyl or cylinder airmass changes during a no-lift shift that I can take advantage of to fool the PCM into retarding timing?
I will work on posting up a log during some No lift shift events
Last edited by LQ4-E39; 02-06-2018 at 10:21 AM.
02-06-2018, 11:11 AM
#26
Here is a log from some No Lift Shift events (full throttle, press clutch to floor, quickly perform shift, release clutch. Never let off the gas). You can follow it by watching the TPS stay close to 99.6%, and speed will actually spike (wheelspin) as I left the clutch out, followed by a drop in revs as it regains traction.
Unfortunately there aren't any big airmass changes which at this point is the only control I have over changing timing during an event like this. But, there must be some other parameter I don't know about that's rapidly changing during a NLS (look at the O2 sensors switching as the mixture goes full rich when the spark gets temporarily shut off). I'd love to take advantage of that and use it as a control to retard timing...
The last ditch effort is adding fuel above 5500rpm (which is where NLS occurs) but this will probably kill some power and have negative effects elsewhere so I'd rather not pursue that
Unfortunately there aren't any big airmass changes which at this point is the only control I have over changing timing during an event like this. But, there must be some other parameter I don't know about that's rapidly changing during a NLS (look at the O2 sensors switching as the mixture goes full rich when the spark gets temporarily shut off). I'd love to take advantage of that and use it as a control to retard timing...
The last ditch effort is adding fuel above 5500rpm (which is where NLS occurs) but this will probably kill some power and have negative effects elsewhere so I'd rather not pursue that
02-06-2018, 02:14 PM
#27
Here is a log from some No Lift Shift events (full throttle, press clutch to floor, quickly perform shift, release clutch. Never let off the gas). You can follow it by watching the TPS stay close to 99.6%, and speed will actually spike (wheelspin) as I left the clutch out, followed by a drop in revs as it regains traction.
Unfortunately there aren't any big airmass changes which at this point is the only control I have over changing timing during an event like this. But, there must be some other parameter I don't know about that's rapidly changing during a NLS (look at the O2 sensors switching as the mixture goes full rich when the spark gets temporarily shut off). I'd love to take advantage of that and use it as a control to retard timing...
The last ditch effort is adding fuel above 5500rpm (which is where NLS occurs) but this will probably kill some power and have negative effects elsewhere so I'd rather not pursue that
Unfortunately there aren't any big airmass changes which at this point is the only control I have over changing timing during an event like this. But, there must be some other parameter I don't know about that's rapidly changing during a NLS (look at the O2 sensors switching as the mixture goes full rich when the spark gets temporarily shut off). I'd love to take advantage of that and use it as a control to retard timing...
The last ditch effort is adding fuel above 5500rpm (which is where NLS occurs) but this will probably kill some power and have negative effects elsewhere so I'd rather not pursue that
02-06-2018, 03:25 PM
#29
https://www.youtube.com/watch?v=GwSl...ature=youtu.be
I suppose the first step is to unplug the IAT with engine off, key on while scanning with HPT and see if the IAT reading goes to 14F. hopefully it does. Then it should be as simple as using the clutch switch (cruise switch actually) to trigger a relay to kill the IAT connection. That would be wired to a pushbutton switch so that I don't have the "fireball mode" kick in during normal driving using the clutch.
The only question is if "unplugging" the IAT will throw a code, I don't want to deal with a CEL. Maybe use an inline resistor to trigger it to the correct "temp"? I need a chart that shows resistance vs IAT for a 2000 C5...
but i'm sure that resistance chart should be easy to find. GM uses the same IAT sensor in just about everything.
02-09-2018, 06:42 PM
#33
TECH Fanatic
Please keep us updated on the progress on this. I have the heads and intake off right now and I also really miss my snap crackle pop I used to have before stroking out my LS3.
I was also considering doing the IAT grounding trick, because I love playing with switches... lol. By far my favorite switch in the car is my electric cutout switch. Got a pair of QTP's on the headers... It is deafening, but awesome. I call it 'merica mode. Normal is labeled "suppressed"... It is more than useful when a Honda with a can on it starts barking at my door. I just "tune them out" and I am pretty sure their ***** shrinks when their car starts vibrating from the sound. Not a single one of them has had the ***** to try and run me. If I were them I wouldn't either.
But yes, IAT ground switch would be most convenient to wire in now while my engine is back apart for more go fast mods. I have an auto though, so I won't have the NLS option, but it would be cool to be able to turn the crackle on or off... As you described "fireball mode" lol. It might also be actually useful for some spray too.
I was also considering doing the IAT grounding trick, because I love playing with switches... lol. By far my favorite switch in the car is my electric cutout switch. Got a pair of QTP's on the headers... It is deafening, but awesome. I call it 'merica mode. Normal is labeled "suppressed"... It is more than useful when a Honda with a can on it starts barking at my door. I just "tune them out" and I am pretty sure their ***** shrinks when their car starts vibrating from the sound. Not a single one of them has had the ***** to try and run me. If I were them I wouldn't either.
But yes, IAT ground switch would be most convenient to wire in now while my engine is back apart for more go fast mods. I have an auto though, so I won't have the NLS option, but it would be cool to be able to turn the crackle on or off... As you described "fireball mode" lol. It might also be actually useful for some spray too.
07-04-2018, 03:24 PM
#34
Teching In
Join Date: Sep 2007
Location: Southampton UK
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
Hi, any update with this. I have a TVR Cerbera with a supercharged LS1. The USP of a Cerbera is it’s pops and bangs on the overrun, completely mental from the factory as TVRs always are. I been trying for ages to replicate the effect.
With Dfco switched off and timing set to around -3 deg (1200rpm up) for the top row of the spark tables I get a good cackle on decel but only from about 2000rpm with the throttle shut. I too need to add a bit of throttle on decel to get the same effect further up the rpm’s. Setting the top timing row to -15 gives a great cackle effect but again it needs to small throttle input to work.
I’ll try adjusting the tumble flap min TPS value. But I’m wondering if it more air related, maybe need to look at the IAC position during decel but would assume this would be open at high rpm to “catch” the idle as the rpm’s drop
Cheers
With Dfco switched off and timing set to around -3 deg (1200rpm up) for the top row of the spark tables I get a good cackle on decel but only from about 2000rpm with the throttle shut. I too need to add a bit of throttle on decel to get the same effect further up the rpm’s. Setting the top timing row to -15 gives a great cackle effect but again it needs to small throttle input to work.
I’ll try adjusting the tumble flap min TPS value. But I’m wondering if it more air related, maybe need to look at the IAC position during decel but would assume this would be open at high rpm to “catch” the idle as the rpm’s drop
Cheers
08-13-2018, 09:50 AM
#35
Please keep us updated on the progress on this. I have the heads and intake off right now and I also really miss my snap crackle pop I used to have before stroking out my LS3.
I was also considering doing the IAT grounding trick, because I love playing with switches... lol. By far my favorite switch in the car is my electric cutout switch. Got a pair of QTP's on the headers... It is deafening, but awesome. I call it 'merica mode. Normal is labeled "suppressed"... It is more than useful when a Honda with a can on it starts barking at my door. I just "tune them out" and I am pretty sure their ***** shrinks when their car starts vibrating from the sound. Not a single one of them has had the ***** to try and run me. If I were them I wouldn't either.
But yes, IAT ground switch would be most convenient to wire in now while my engine is back apart for more go fast mods. I have an auto though, so I won't have the NLS option, but it would be cool to be able to turn the crackle on or off... As you described "fireball mode" lol. It might also be actually useful for some spray too.
I was also considering doing the IAT grounding trick, because I love playing with switches... lol. By far my favorite switch in the car is my electric cutout switch. Got a pair of QTP's on the headers... It is deafening, but awesome. I call it 'merica mode. Normal is labeled "suppressed"... It is more than useful when a Honda with a can on it starts barking at my door. I just "tune them out" and I am pretty sure their ***** shrinks when their car starts vibrating from the sound. Not a single one of them has had the ***** to try and run me. If I were them I wouldn't either.
But yes, IAT ground switch would be most convenient to wire in now while my engine is back apart for more go fast mods. I have an auto though, so I won't have the NLS option, but it would be cool to be able to turn the crackle on or off... As you described "fireball mode" lol. It might also be actually useful for some spray too.
Hi, any update with this. I have a TVR Cerbera with a supercharged LS1. The USP of a Cerbera is it’s pops and bangs on the overrun, completely mental from the factory as TVRs always are. I been trying for ages to replicate the effect.
With Dfco switched off and timing set to around -3 deg (1200rpm up) for the top row of the spark tables I get a good cackle on decel but only from about 2000rpm with the throttle shut. I too need to add a bit of throttle on decel to get the same effect further up the rpm’s. Setting the top timing row to -15 gives a great cackle effect but again it needs to small throttle input to work.
I’ll try adjusting the tumble flap min TPS value. But I’m wondering if it more air related, maybe need to look at the IAC position during decel but would assume this would be open at high rpm to “catch” the idle as the rpm’s drop
Cheers
With Dfco switched off and timing set to around -3 deg (1200rpm up) for the top row of the spark tables I get a good cackle on decel but only from about 2000rpm with the throttle shut. I too need to add a bit of throttle on decel to get the same effect further up the rpm’s. Setting the top timing row to -15 gives a great cackle effect but again it needs to small throttle input to work.
I’ll try adjusting the tumble flap min TPS value. But I’m wondering if it more air related, maybe need to look at the IAC position during decel but would assume this would be open at high rpm to “catch” the idle as the rpm’s drop
Cheers
