DIY Rom tuning for exhaust pops and backfires W/ romraider

[Totalrecall]

Originally Posted by eddieflyinv

@504 @sqd @dhuang finally got around to this.
Just an example of my current settings for overrun, not too much has changed from my previous experiment, mind you im just starting playing with it again

First 3 tables are located in Fueling - Overrun Folder
- Overrun Initial Enrichment @ 1.2
- Fuel Cut Threshold @ 6000
- Overrun Enrichment Activation Delta @ -15
Last 2 Tables found in Ignition Timing - Advance Folder
- Rescaled the Base Timing Idle (In Gear Above Speed Threshold) table, like I mentioned before, my preference was for this to only start occurring when the engine was almost warmed up
- Raised the value in Base Timing Idle Vehicle Speed Threshold table, this helped quite a bit to avoid low speed jerkiness (10km/h because canada)

As mentioned before, may have to play with the amount of Overrun Enrichment and the values used to retard timing in the Base Timing Idle table, previous tunes were Stage 1 with Stock headers and catless overpipe, and with the stage 2 tune and no cats I have reduced Initial Enrichment from 2.8-1.8 to 1.2
Things acheived
- Lots of explosive crackles at high rpm lift,
- Crackles between shifts (with slight delay, seems to be more time related than rpm related, so OL/CL transition delay settings may potentially alter that)
- downshift bangs, lately they seem to be singular (only had this tune up again since last night) but theyre loud, though they are not rpm limited anymore, (never used to get them above 3krpm before)
- feathering popping/crackle, find that spot and it will pop endlessly, often on tip in there is a slight initial crackle, and if you have your cruise on going down hill your car will sound like automatic gunfire the whole way down 🙊 not sure if the tip in crackles can be gotten rid of, seems to be table switching delay so maybe messing with the OL/CL transition delays could reduce or eliminate that as well.

Sent from my LG-H812 using Tapatalk

has anyone tested this on e85??

[hestekinj]

Originally Posted by Vin

This is -5 , higher frequency of pops and also the sound is higher tone, popcorn:

https://photos.app.goo.gl/4liEBWosYpzRdEFK2

This is +5 on a dyno, lower frequency and a lower tone, more a burble/fart than a pop:

https://photos.app.goo.gl/w4IYkqxjd7nPwEqC3

Results will vary per exhaust setup. I'm using a catless UEL and a high flow cat in the front pipe, resonated mid pipe and aftermarket (custom) axle back.

Thanks for the information and video examples!

One other thing I just thought to ask; what initial enrichment are you running?

[bababooey]

yesterday I tried +5 all the way down first column and wasnt satisfied, like mentioned above more tame. so im going back to -6. I found going past single digits (-12) didnt respond quite like i thought it may. but I also think it'll take more than the 20 miles to get the fuel trims dialed in before i really begin to pop again.

[hestekinj]

Originally Posted by bababooey

yesterday I tried +5 all the way down first column and wasnt satisfied, like mentioned above more tame. so im going back to -6. I found going past single digits (-12) didnt respond quite like i thought it may. but I also think it'll take more than the 20 miles to get the fuel trims dialed in before i really begin to pop again.

Based on your response it sounds like you're changing the base timing b 'column' to get the pops/burbles when you feather the throttle? @Vin can correct me if I'm wrong, but I believe he is running the 'lift off' pops/burbles method where you adjust the intial enrichment, and re-scale the base timing idle (in gear) (above speed threshold), which may be why you weren't getting many pops.

[bababooey]

Originally Posted by hestekinj

Based on your response it sounds like you're changing the base timing b 'column' to get the pops/burbles when you feather the throttle? @Vin can correct me if I'm wrong, but I believe he is running the 'lift off' pops/burbles method where you adjust the intial enrichment, and re-scale the base timing idle (in gear) (above speed threshold), which may be why you weren't getting many pops.

yeah thats correct because it was easiest to understand. im a lil hesitant to mess with the enrichment stuff. but i was getting pops coming off throttle & often back on throttle, that transition where for a short time the pedal travels though that column. but like mentioned +5 equated to burbles more.

[Vin]

I did run 1.2 enrichment with the overrun method. I've switched to Ecutek and now run the Base timing method, but with some custom Ecutek tables automatically feathering the throttle on overrun. The result is the same, +5 timing and nice pops. Thus I don't think it matters which method you use, the result of the chosen timing will be the same.

[Brayden_23]

Want to thank all the contributors in this thread!

Finally got around to trying this out. Only adjusted the 0.15 load range on Ignition B table. Due to the results I read about through this thread, I decided I only wanted modest pops so I wouldn't get tired of it. I put +5 from 2600 to 5400, then above that dropped it to 2.5.

I really like how giddy this makes me. If I am trying to do it, they can be a little obnoxious. But what I've really appreciated is the pop on upshifts. I have a track day coming up next month so I am excited to see how this sounds when doing actual performance driving and not just cruising around town.

[D_Thissen]

I'm running this setup right now: +10 @ 2500, +5 @ 3500, +2.5 @ 4500, 0 @ 5500.

You get some nice burbles below 3500, anything above 4500 is a loud pop. It sounds fine when you're downshifting on the highway, but it's a bit obnoxious around town. I might try +10, +10, +5 and +5 and see if that helps.

[jerryzilla]

Originally Posted by jerryzilla

Any way to get the car to pop with the overrun method while in neutral? i changed base idle timing (neutral) to -8 from 2500 onwards, but no pops

anyone?

[jerryzilla]

Originally Posted by D_Thissen

I'm running this setup right now: +10 @ 2500, +5 @ 3500, +2.5 @ 4500, 0 @ 5500.

You get some nice burbles below 3500, anything above 4500 is a loud pop. It sounds fine when you're downshifting on the highway, but it's a bit obnoxious around town. I might try +10, +10, +5 and +5 and see if that helps.

I'm running -8 across the board and i'm getting gunshots on downshifts. Rings my ears sometimes lol

[Totalrecall]

Originally Posted by eddieflyinv

@504 @sqd @dhuang finally got around to this.

Is this normal, My Base timing idle in gear above speed threshold only goes to 1800, VS pic above. And all my edits are grey.... Is it safe to continue?




V4.01 tune with definition from @elBarto

[elBarto]

Originally Posted by Totalrecall

Is this normal, My Base timing idle in gear above speed threshold only goes to 1800, VS pic above. And all my edits are grey.... Is it safe to continue?

Yes, the grey color means the cell has been selected (you did that while editing)
And the "in gear table" has been rescaled.
You can change the values above the datacells as well.

[stefodrom]

Originally Posted by Originally Posted by jerryzilla Any way to get the car to pop with the overrun method while in neutral? i changed base idle timing (neutral) to -8 from 2500 onwards, but no pops
jerryzilla

anyone?

I got the same issue, please help... i wanna get pops in neutral with overrun :/

[MrStickers]

Originally Posted by jerryzilla

I'm running -8 across the board and i'm getting gunshots on downshifts. Rings my ears sometimes lol

Got a video?