Pops & Bangs/Retarding Timing

[HermaN]

Is it possible to add pops & bangs to a car via NIStune? With EcuFlash for Evo's you can add -'ve timing in the map from 0 - 20% load at RPM's 2500 - 7000

That way when you lift off the throttle and rest your foot on it, you can get the car popping & banging and even spitting flames. Evo's have an SAS system which can be enabled to dump air into the exhaust manifold and help, but simply retarding the timing usually works too.

Can this be done via NIStune? Can't seem to retard the ignition advance at all in it....

[Matt]

The timing table goes from 0 - 127 (!) degrees so nothing you can really do there to get negative

Few of the jap tunes I have seen put a heap of fuel in at high rpm, low load to get extra fuel on decel to get a pop happening then

[blu3man]

Get a wa###r valve you get pops and bangs then because of the excess fuel build up in your exhaust.

I spit flames while downshifting sometimes on the track, not much, but a bit.

Just load more fuel .... spray and pray

[HermaN]

The timing table goes from 0 - 127 (!) degrees so nothing you can really do there to get negative

Few of the jap tunes I have seen put a heap of fuel in at high rpm, low load to get extra fuel on decel to get a pop happening then

Ah, cheers Matt, extremely helpful as always. However, I have found a bug in NIStune, I did find a way for it to put -'ve timing into the map, but never actually tested it in a car, was just playing with the map and noticed this glitch, will post it in the bugs section of the forum tho.

Get a wa###r valve you get pops and bangs then because of the excess fuel build up in your exhaust.

I spit flames while downshifting sometimes on the track, not much, but a bit.

Just load more fuel .... spray and pray

I'm guessin the 3 ### are the letters ken (not in that order). What on earth is a wa***r valve? What does it do?

cheers!

[blu3man]

Atmospheric Venting blow off valves.

AKA Pooooshhhh valves.

It moves air which should be in your intake piping... out of your intake piping. However your ecu will think that air is still there and spray all the fuel necessary for the x amount of air you just lost. Apart from the cool sound (questionable), you spray far too much fuel into your engine momentarily (and while some people say this can cool the engine down its negligable) causes dirty combustion, excessive fuel in your exhaust system and if enough, flames.

They also start to leak after a while and everyone on nissansilvia.com wonders where thier boost leak is and talk about how they play with thier BOVs (which each time i hear "play with my bov" in my head, bov is replaced with pe###$).

One of the most useless things you can ever put on your car.

Albeit... I haz one... Why? It was free, and who doesn't like free stuff.

[HermaN]

Ah right! A VTA BOV!! I know what you're getting at now. I used to have one in my Evo and it just gave 1 massive BANG every now & then when I had it, but since going back to a re-circ it's more lots of pops, like machine gun fire. lol

[iguanapeluda]

Hi Guys!,

The last week I have installed a Nisunte in My Zed with Stock turbo´s and 555cc deatschwerks inyectors.



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Now, I would like to make a "second map" to have some Bangs and Pops with excess of fuel, my tuner tell me the following to have these "Bang´s":

You actually want it lean on release so that the fuel is still burning as it exits exhaust. First, you need to remove the fuel cut as this prevents any fuel at all during deceleration – set ‘Fuel cut’ table to all 8000 and ‘Fuel Recover’ to all 7900 – from there you should already get some pops! After that you need to trim the high rev / light throttle fuelling until it sounds like you want

Now I try to make this with Nistune but I don´t know How I make it:





Uploaded with ImageShack.us

is it correct?

Thanks!!!

[Munkul333]

how will this allow pops and bangs? Unless you have no BOVs at all, in which case the airflow reversal through the MAFs might initially push the TP load really high. (I think this happens to Immy21, seen it on his logs)

But doing away with the fuel cut leaves you no protection in the event of an actuator hose failure, or similar. Possible engine failure just for the sake of a few pops? meh...

[bachig24u]

Most engines can be tuned to blow flames and give a nice bang during up gearing also.
Over fuelling and lazy timing at high rpm and waste gate dumping on the road.

lights up the whole street at night and scares the daylights out of the car you're overtaking.

if you want a pop and bang to blow the muffler off it's as easy as dialling the CAS to TDC or less.

add the difference to the ignition timing so the engine doesn't lose power, this will add more scope for adjustment.

[supersayianjim]

or, you can get a beer rev limiter??

[iguanapeluda]

Well!

yesterday I was playing with my Zed and searching a minimum of POP AND BANGS.. (I have an EVO IX with Link ECU and is it lovely with 40degree retard....)

In nistune, the maximum of retard is 0 degree....

I have made the next modification:

1º. Modify the table of IDLE/DECELERATION TIMING vs RPM to 0º.
2º. Never cut the fuel, FUEL CUT TABLE AND FUEL RECOVER AT 6500 rpm..like the photo:
3º. Up the AFR in decel region in fuel maps



Well, now I have some questions:

1º.Is it possible make that the retard cells are until 6500rpm??, the table finished at 3000rpm..
2º.Is is possible to adjust the time of the fuel cut?, in LINK ECU I can make a retard of 2 seconds to make the fuel cut.
3º. I don´t understand the "IGNITION RETARD vs THEORETICAL PULSEWIDTH"...could you explain me?




Do you think to make more modifications to make more pops and bangs?, I have think redial de CAS ...

Thank you.

[Matt]

1. Fuel cut / recovery tables are only between a small RPM range normally on deceleration. You would increase the tables if you reach that high in the first place to make the fuel cut (which will be value of injection latency)
2. Not possible to adjust the timing of the fuel cut for each ECU
3. TP = load so based on the load is amount of ignition retard. Not sure for the Z32 ECU would need to check it out further

If you retarded CAS then every timing table/value would have to be adjusted to compensate. May affect target idle closed loop also...

Ideally adding negative retard timing in a firmware update during certain conditions would be the best way to implement this

[iguanapeluda]

1. Fuel cut / recovery tables are only between a small RPM range normally on deceleration. You would increase the tables if you reach that high in the first place to make the fuel cut (which will be value of injection latency)
2. Not possible to adjust the timing of the fuel cut for each ECU
3. TP = load so based on the load is amount of ignition retard. Not sure for the Z32 ECU would need to check it out further

If you retarded CAS then every timing table/value would have to be adjusted to compensate. May affect target idle closed loop also...

Ideally adding negative retard timing in a firmware update during certain conditions would be the best way to implement this

Thank you Matt, finally I have set around 2500rpm fuel cut for make dome pops at low speed and Advance to 0 when the TPS Is ON decelerating and make some pops when the exhaust Is hot.

In the next upgrades...if you cAn modificate to put ...-15/-20 degree or advance in decel and can change the delay or the fuel cut to 1.5-2 seconds to put fuel in the exhaust....the pops and fires will be great

[Matt]

See what I can do... depends on factory coding and if I can achieve this

[iguanapeluda]

See what I can do... depends on factory coding and if I can achieve this

Thank you Matt.