Backfire tune my caprice 13

[Varto20]

HI EVERYONE wanted to do this for a long time on my chevy caprice 13 6l80 but couldn't figure it out I wanted it to backfire whenever I changed gears in s(sport mode) from 1>2>3>4>5 whenever I Rev it over 4200 so basically whenever I raced someone but still didn't get the perfect idea of how to do it I know that I should go to spark retard the timing on vacuum area on wanted rpm so that will be from 4200 until 8000rpm on let's say just about 0.20 amount of air (vacuum area) then go to my maf table to richen those cells but that's basically it whenever I am at the maf table I get lost should i just richen it to 0.20 based on the spark table that i retarded earlier in general i don't know where to richen the maf table and I don't know how to make it only backfire on those certain rpms at s mode only when I shift manually so if I am at D I want nothing to happen but I couldn't figure it out so I just backed off for now until I get it completely figured out it would be nice if someone put us on the right path and thank you guys

[rhighfil82]

I'm tryna get rid of backfire on mine. 😹

Ya know, you might look into Nitrous tuning.. There are some guys rigging up a switch with a resistor to their sensors.. I think it is the map sensor. Whenever that switch is triggered, the timing is retarded for the nitrous..and you could probably add more fuel that way too.

[Varto20]

Why are you trying to get rid of it I think it's very cool .for the nitrous tune do you mean that I can control the backfire with a switch and manpulitaed as I want whenever I am spraying?

[rhighfil82]

I didnt know you had nitrous..but I was thinking you could use the same method to cause backfires at the push of a button. The switch and resistor basically tricks your engine into thinking it's -40? outside, and you can set up specific timing and fueling for that condition.

[Varto20]

Okay I get it now so where can I find this device and how much does it cost ,as for nitrous I don't have it right now I am only running bolt ons at the moment but soon enough I will have 100 shots of happiness (wet kit)+ a cam .but for now I want to know how to tune in hp tuners for backfires I got most of it but I am clueless on how to make it only backfire in s mode whenever over 4200rpm I got the spark retard -40 on vacuum area at I think 0.20 and less so bacically whenever I get of the gas on 4200 rpm and above until now everything is good of course I disabled dfco..etc now for riching the maf table where do I richen it at 0.20 and less or should I make some logs I am just clueless there I need help over there .I want to know how make it backfire every time I shift in s mode over 4200 but whenever it's in D I don't want to do anything that's a little bit tough to do but I hope this thread will be seen by a pro tuner and give us some tips on how to do it correctly.

[5FDP]

You can't just remove fuel the MAF or add fuel to the MAF like that, that's not how it works.

The MAF doesn't just stop reporting air flowing past and drop like a rock on a shift. Look at your logs when you are driving it, the MAF airflow values in the tune get higher as the rpm's do, then in a smooth motion they get lower at the rpm's fall on the shift and go right back up again. It's not like a switch where you can just whack it with fuel at whatever rpm point you want to create a pop in the exhaust on a shift.

I have no idea how you are going to be able to do this on a regular automatic transmission. The import world with the DSG transmission can do this stuff pretty easy it seems. Because they are able to time the fuel and spark cut just right to get the noise.

[Varto20]

So basically I need to forget about making it only backfire in s mode it's gonna backfire in both .and I can't just richen the maf table I need to make logs and then from my logs richen the areas in the table where I want it to backfire basically ?

[rhighfil82]

Here's the mod for those that don't know about it...

https://ls1tech.com/forums/nitrous-o...de-system.html

[Varto20]

Thank you very much I saved this for the future since I will be runing nitrous maybe I will end up using this device eventally but as for now I am determined to do this using only hp tuners

[Varto20]

You can't just remove fuel the MAF or add fuel to the MAF like that, that's not how it works.

The MAF doesn't just stop reporting air flowing past and drop like a rock on a shift. Look at your logs when you are driving it, the MAF airflow values in the tune get higher as the rpm's do, then in a smooth motion they get lower at the rpm's fall on the shift and go right back up again. It's not like a switch where you can just whack it with fuel at whatever rpm point you want to create a pop in the exhaust on a shift.

I have no idea how you are going to be able to do this on a regular automatic transmission. The import world with the DSG transmission can do this stuff pretty easy it seems. Because they are able to time the fuel and spark cut just right to get the noise.

So for example just to make sure I got this right after i retard my spark tables for backfire .
Base
(high octane ,low octane)(-35 on 1600 rpm to 8000 rpm from 0.08 to 0.20 spark air mass )


Idle spark advance
(base ,costdown)(-35 at same rpm's and spark air mass as my base tables )

Minimum spark
Base(same rpms at same spark air mass as the above tables to allow max retard since it's only allow up to -10 so now it will allow -35 retard)

Now I want more flames so I will tune my maf.



whenever I am logging my maf to richen those areas to make the car make more flames I do a as usaul right disable close loop
Fuel
(disable dfco,disable cot,disable o2 readiness ect ,disable ltft)

Airflow
Dynamic
Disable dynamic airflow.

Now I just tune the maf like I normally do my question is which pids do I need remember I am tuning these areas when I am off the throttle where the airflow is low to richen it and get flames .
The wide band will help me see the rich/lean areas but I have noticed there is a pid for cylinder air mass in grams is that what I am supposed to use to rich those areas and how do I go about that do i richen every cell individually on my maf table.


For example at my scanner at 1900 rpm the pid shows 0.20g cylinder air mass and the wide band shows -2 rich on 5100hz so now do I go my editor airflow,maf table and go to 5100 hz and multiply that cell by 1.07 for example to give me the flames I want or is there another way to do this .???



Note :Any beginner that sees this what you are seeing is only my assumptions from which I have gathered don't try to copy what I am doing it could blow your motor up I am asking for info only and this is an example it's not a real tune I am just learning as you are .

[5FDP]

You can't just add fuel to the MAF curve where ever you want. That is going to throw everything off, ruin fuel mileage and make normal driveability worse.

[Varto20]

You can't just add fuel to the MAF curve where ever you want. That is going to throw everything off, ruin fuel mileage and make normal driveability worse.

OK so everything I did was right exept for maf section lol did I do it 100%correct or is there something that I forgot to do to make this backfire tune perfect

[Xr650jkallen]

On my 4l60 truck I ran a log and did some runs taking note on what cells where getting hit on decel. I then changed those cells to 10 degrees on both high and low octane timing tables. It pops like crazy on decel, every now and again I get a good crackle on the 1-2 shift.

[Xr650jkallen]

This will shorted the lifespan of your cats if you still have them.

[Varto20]

On my 4l60 truck I ran a log and did some runs taking note on what cells where getting hit on decel. I then changed those cells to 10 degrees on both high and low octane timing tables. It pops like crazy on decel, every now and again I get a good crackle on the 1-2 shift.

How were you able to make it backfire between gears with a simple auto trans ?

[Xr650jkallen]

My throttle body is cable driven. If I want it to pop on the 1-2 shift it just takes a quick throttle lift. I have my trans tablets pretty aggressive on the downshift and I dont lock my torque converter until 58mph and only in 4th gear. This increases engine braking and gets the motor down into those high vacuum areas were I have the timing pulled and it pops like crazy. 10 degrees is almost to much popping for my taste though.

[Varto20]

My throttle body is cable driven. If I want it to pop on the 1-2 shift it just takes a quick throttle lift. I have my trans tablets pretty aggressive on the downshift and I dont lock my torque converter until 58mph and only in 4th gear. This increases engine braking and gets the motor down into those high vacuum areas were I have the timing pulled and it pops like crazy. 10 degrees is almost to much popping for my taste though.

I have to say that's impressive considering you are doing this with a 4l60 transmission but I just don't get how did you do it could you post a tune file telling me what have you changed I kind of want to do the same with my 6l80 here I will appreciate it if you could just show me what to change