LQ4-E39

iTrader: (7)

Newb tuner looking for some info. Trying to blow some flames with my 2000 C5 6 speed, already has the N2MB WOT BOX installed, but only gets a big backfire once in every 20 No Lift Shifts (which cuts spark). I want to make this something I can do "on demand". Above a certain RPM (say, 4000, would be fine).

Shutting DFCO completely off doesn't seem hard, but where can I find the table to retard timing in the "closed throttle" (transition) area for certain RPMs? Is there a way to retard timing as the clutch is pushed in during a shift?

I realize that this may not be everyone's style, so flame suit on. Thanks in advance.

Forgot to mention that I'm running full longtubes and a catless x-pipe. No cats anywhere on the car. Stock axleback for now but has cutouts well before the mufflers. Not into the old "spark plug flamethrower hot rod" thing.

Here's the effect I am going for:



@ 0:55

Currently this is the effect I'm getting.

just a lot of sputtering and gurgling (like it's supposed to during the 2 step).

Happy Jim

DFCO off, put timing to 10deg BTDC for MAP pressures sub 30 KPA (ie loads of Vac during overrun) - that’ll get you tons of snap/crackle/pop on the overrun and also during upshifts.

No idea what an N2MB is though...off to google now

Jim

LQ4-E39

iTrader: (7)

http://www.npcompleteperformance.com/wotbox

Thanks for the tune info. Regarding the timing, I'm looking in the main spark advance tables (low octane and high octane) and don't see the y-axis showing MAP (kpa)...only in cylinder airmass (g). I understand these are different measurements and are not able to be directly converted.

Is the idea to log a pull and a few shifts showing the MAP pid vs cylinder airmass pid vs RPM and then be able to reference one versus the other for a "translation"?

from this thread:

https://ls1tech.com/forums/pcm-diagn...-cylinder.html

Happy Jim

Hi,


Joe is of course correct in how he suggests to do it, I think I a bit more "dumb" and just logged KPA, on playback I linked to the tune tool (EFI Live) and watched where the cells were highlighted during overrun.


In short though...0.08 up to 0.2 Grams/Cyl worked for me (Table {B5913})


I started at 20 and moved closer towards zero until it got too obnoxious even for me Just checked and I've settled at 15 degs.


Have fun ;-)


Jim

TrendSetter

i did it with a msd 2 step to pull timing, i tied in the activation wire with the nitrous activation with efilive. with the nitrous tables you add some fuel and pull timing.
then you activate the 2step with a clutch switch and when you hit the rev limit it should blow flames out.
i did it to spool my turbo.

LQ4-E39

iTrader: (7)

I think that's the problem, I'm not able to pull timing using the N2MB WOT BOX. Have to figure out a way to do it in the tune.

truckdoug

iTrader: (25)

use the IAT cut trick. throw the signal to ground and it'll default to the coldest temperature column in the table (-8* F or something like that) and then pull your timing in that column.

it works, but's very hard on exhaust valves

LQ4-E39

iTrader: (7)

Doug, can you elaborate on the valves? Hard how? Burning and eventual pitting due to richness? Physical stress/force due to combustion occuring in the exhaust?

Seems like it would be really difficult to get that to coincide with a shift.

truckdoug

iTrader: (25)

well you're aiming for that anti-lag effect right? that is basically retarding the timing until the combustion event happens with the exhaust valves open, hence the fireballs

it's a lot of heat to put into an open valve. they are cooled by transferring heat energy to the valve seat, into the head and cooling system.

It's probably not a big deal to brap a couple here and there, but staying on it like i see subaru guys do...maybe not a great idea

JakeFusion

iTrader: (7)

Iconel is your friend.

G Atsma

Good stuff!

LQ4-E39

iTrader: (7)

Here's the most current update...spent a couple hours tonight with mixed results.

I started off my turning the DFCO Enable temp to 280F so that it was disabled. I then altered the Main Spark Table (both low and high octane) to 5 degrees of advance under the following conditions:
2000-8000rpm
.08-.16g (Cylinder Airmass, high vacuum condition)

Only while letting off the gas abruptly was I able to get the "burble/crackle" effect I'm going for, and it was only for an instant. I was watching the live Scanner and did indeed see the timing advance drop to 5* before readvancing up to the 20s and 30s (without any throttle input). If my "theory" is right, I should be getting a bunch of crackle in that RPM window when the cylinder airmass drops under .16g.



Ironically when the car decelerates in gear on its own fairly low in the rev range it begins to pull timing on its own (see the jagged timing to the right of the highlighted point) and the crackle effect gets nice, but it's too low in the rev range to sound good.

I am obviously not in the right table OR something else is interfering with the timing reduction command I've entered.

Here are my tune and logs for those who are able to take a look. I feel like I'm so close!

LQ4-E39

iTrader: (7)

Here are the tune and logs.

TrendSetter

you need to add fuel and retard timing at wot on the 2 step to get what you want.
use the iat trick or the nitrous tables(if hpt has it?)

Happy Jim

I wonder if it dips to 5 degs in the high octane spark table, you get the cackle, then it drops into a base spark or idle table hence it’s taking the spark back from those tables (TP dependent)

I’m EFI Live I’m afraid and haven’t played with HPT

Regards

Jim

LQ4-E39

iTrader: (7)

I was able to get much better results when retarding timing in the Base Spark Tables as well as the Main (high/low octane). Interestingly you still need to have a tiny amount of throttle open (haven't logged to see %) to get that devilish burble/crackle on decel.

I am still struggling to think of a method to retard timing during the No Lift Shift...only thing I can think of now is the IAT trick (wire it to the clutch switch?). Would really love to do this in the tune and not to have to install more hardware and further complicate things..

Dirty Vegas

iTrader: (12)

Very curious to see where this goes. I've got a 2015 Chevy SS Sedan A6, and I'd like to get a more aggressive sound on upshifts at WOT and decel. Looking for it to sound more like the MB AMG cars do on upshifts. It's a very distinct crack/bark. Very interesting thread, as I haven't seen many pertaining to tuning for sound.

G Atsma

That's because most around here are FAR more concerned about tuning for POWER. Tuning for sound is for posers...

LQ4-E39

iTrader: (7)

Everyone is entitled to their own opinion, so that's fine.

If that's the case, I wonder why there are so many OEMs today introducing powertrain sound as an important part of the driving experience. (Mercedes' distinctive BRAP on shifts, Ford and GM piping phyical intake noise into the cabin, BMW and Jaguar with their burble on overrun).

G Atsma

I doubt they tuned to do just that, some tunes AND exhaust systems just happen to sound good. And in Ford and GM's case, piping sound doesn't affect the tune.