DIY Rom tuning for exhaust pops and backfires W/ romraider - Page 22 - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

ort895 · 02-27-2016, 09:49 PM

i just want the damn pops and crackle on downshifts lol

eddieflyinv · 02-28-2016, 08:07 PM

Quote:

Originally Posted by VeilSide

The overrun function is working perfectly. Just set the RPM delta to -10 or whatever and set a desired angle in the Base Timing Idle (in gear) table.

Unfortunately it seems that the pops and bangs trigger the knock sensor and the IAM is constantly kept at 0

I was thinking too ive had my IAM at 0 before for an entire log but after exiting and then re entering the diagnostics it went to normal... Doubt its actually at 0 lol

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shaynek · 02-29-2016, 04:42 PM

What will give you the loudest pop? -15 or -5?

_gt86_user · 02-29-2016, 10:48 PM

Quote:

Originally Posted by shaynek

What will give you the loudest pop? -15 or -5?

-15 in Base timing B

shaynek · 02-29-2016, 11:00 PM

Quote:

Originally Posted by _gt86_user

-15 in Base timing B

I did -15 but it sounds like popcorn. i have headers and a catback exhaust so i'm guessing it's only loud when your straight piped

_gt86_user · 03-01-2016, 12:08 PM

Quote:

Originally Posted by shaynek

I did -15 but it sounds like popcorn. i have headers and a catback exhaust so i'm guessing it's only loud when your straight piped

Yeah it really only works well with a full catless system (front pipe as well)

shaynek · 03-01-2016, 04:27 PM

Quote:

Originally Posted by _gt86_user

Yeah it really only works well with a full catless system (front pipe as well)

lol time to upgrade the front pipe haha

VeilSide · 03-02-2016, 03:27 PM

Quote:

Originally Posted by eddieflyinv

I was thinking too ive had my IAM at 0 before for an entire log but after exiting and then re entering the diagnostics it went to normal... Doubt its actually at 0 lol

Sent from my LG-H812 using Tapatalk

Your are right, after another key cycle everything was back to normal. IAM staying at 1 and nice crackles and bangs

Still experimenting with some other values to get it also in higher gears.

eddieflyinv · 03-08-2016, 07:03 AM

Has anyone considered adjusting the Desired Overrun Mass Airflow Tables ? Wondering if adjusting the numbers in those tables to lower values would help with the higher rpm crackles. Less air + initial enrichment = richer mixture that explodes in the exhaust ?
Just figure its an idea as those values rise quite high in the higher rpm range, and with the miniscule amount of fuel we are dropping in there it may be too much airflow and not enough fuel ? Since we cant change the enrichment based on engine speed we could maybe adjust the requested airflow to achieve the same burbles and pops in lower rpm ranges..
Not sure of the side effects though as lowering the numbers at high rpm may change engine braking operation and feel, it makes sense that at higher rpm it requires more air, but would it damage anything to lower the desired airflow ? Id imagine engine braking would become more uncomfortable but im not sure how that would actually play out...
Any experts have a cautionary warning for me before I try it ? Lol

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504 · 03-10-2016, 02:23 AM

I'd love to see some video of this new overrun method of crackle

ort895 · 03-10-2016, 10:33 AM

Quote:

Originally Posted by 504

I'd love to see some video of this new overrun method of crackle

What he said

eddieflyinv · 03-10-2016, 10:12 PM

Aha im actually getting the gf to take a video tonight, i decided to skip modifying mass airflow and instead played around elsewhere and I have it working pretty well

will upload later

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eddieflyinv · 03-11-2016, 12:51 AM

So I still havent gotten it above 3krpm. Unless its between shifts, works well there.. Buuuut this is how its currently working. (there was slight feathering after initial crackle on the first and third pass)
above 3krpm feathering does work well and loudly, but unfortunately it wont crackle on its own above that. Not a clue why at this point in time. Still playin.. I want to figure out a way how.
It does work in all gears however, as long as I am at or under 3000 and within my negative timing rpm ranges, louder burbles noticed in the car during periods of stock base timing idle (34.14) due to the enrichment, but crackles only with negative timing.

Fuel Cut @ 7000rpm across the board
Resume @ Stock
Enrichment @ 0.8ms
Delta Activation @ -15
Base Timing Idle @ Modified and rescaled (will edit with screenshot when I get to my computer)

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VeilSide · 03-12-2016, 06:28 AM

I use OEM fuel cut and resume, enrichment still at 0, delta at -10 and Base Timinge Idle rescaled up to 7000 rpm. With this it bangs and crackles up to redline at times.

I am using +10° at the time but it is still very loud at times so I want to go further with the positive timing.

I have the impression the real influence is within the Overrun Fueling Cut Counter RPM Threshold table, but I still dont know what exactly this does.

02-27-2016, 09:49 PM	#295
ort895 Senior Member Join Date: Aug 2014 Drives: 2013 BRZ Location: North Carolina Posts: 695 Thanks: 195 Thanked 139 Times in 113 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	i just want the damn pops and crackle on downshifts lol __________________ Yeah its an auto, deal with it.

03-11-2016, 12:51 AM	#307
eddieflyinv Senior Member Join Date: Jul 2014 Drives: 2013 Scion FR-S Location: Ireland Posts: 225 Thanks: 133 Thanked 57 Times in 43 Posts Mentioned: 6 Post(s) Tagged: 2 Thread(s)	So I still havent gotten it above 3krpm. Unless its between shifts, works well there.. Buuuut this is how its currently working. (there was slight feathering after initial crackle on the first and third pass) above 3krpm feathering does work well and loudly, but unfortunately it wont crackle on its own above that. Not a clue why at this point in time. Still playin.. I want to figure out a way how. It does work in all gears however, as long as I am at or under 3000 and within my negative timing rpm ranges, louder burbles noticed in the car during periods of stock base timing idle (34.14) due to the enrichment, but crackles only with negative timing. Fuel Cut @ 7000rpm across the board Resume @ Stock Enrichment @ 0.8ms Delta Activation @ -15 Base Timing Idle @ Modified and rescaled (will edit with screenshot when I get to my computer) Sent from my LG-H812 using Tapatalk Last edited by eddieflyinv; 03-11-2016 at 01:04 AM.

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02-29-2016, 04:42 PM	#297
shaynek Senior Member Join Date: Oct 2013 Drives: BRZ Limited; GR86 Location: Nor cal Posts: 316 Thanks: 93 Thanked 81 Times in 59 Posts Mentioned: 10 Post(s) Tagged: 1 Thread(s)	What will give you the loudest pop? -15 or -5?

03-08-2016, 07:03 AM	#303
eddieflyinv Senior Member Join Date: Jul 2014 Drives: 2013 Scion FR-S Location: Ireland Posts: 225 Thanks: 133 Thanked 57 Times in 43 Posts Mentioned: 6 Post(s) Tagged: 2 Thread(s)	Has anyone considered adjusting the Desired Overrun Mass Airflow Tables ? Wondering if adjusting the numbers in those tables to lower values would help with the higher rpm crackles. Less air + initial enrichment = richer mixture that explodes in the exhaust ? Just figure its an idea as those values rise quite high in the higher rpm range, and with the miniscule amount of fuel we are dropping in there it may be too much airflow and not enough fuel ? Since we cant change the enrichment based on engine speed we could maybe adjust the requested airflow to achieve the same burbles and pops in lower rpm ranges.. Not sure of the side effects though as lowering the numbers at high rpm may change engine braking operation and feel, it makes sense that at higher rpm it requires more air, but would it damage anything to lower the desired airflow ? Id imagine engine braking would become more uncomfortable but im not sure how that would actually play out... Any experts have a cautionary warning for me before I try it ? Lol Sent from my LG-H812 using Tapatalk

03-10-2016, 02:23 AM	#304
504 Senior Member Join Date: Feb 2013 Drives: 2014 86 GTS Location: Sydney, Australia Posts: 168 Thanks: 131 Thanked 85 Times in 57 Posts Mentioned: 4 Post(s) Tagged: 0 Thread(s)	I'd love to see some video of this new overrun method of crackle

03-10-2016, 10:12 PM	#306
eddieflyinv Senior Member Join Date: Jul 2014 Drives: 2013 Scion FR-S Location: Ireland Posts: 225 Thanks: 133 Thanked 57 Times in 43 Posts Mentioned: 6 Post(s) Tagged: 2 Thread(s)	Aha im actually getting the gf to take a video tonight, i decided to skip modifying mass airflow and instead played around elsewhere and I have it working pretty well will upload later Sent from my LG-H812 using Tapatalk

03-12-2016, 06:28 AM	#308
VeilSide Member Join Date: Feb 2016 Drives: GT86 Location: Germany Posts: 27 Thanks: 5 Thanked 4 Times in 4 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	I use OEM fuel cut and resume, enrichment still at 0, delta at -10 and Base Timinge Idle rescaled up to 7000 rpm. With this it bangs and crackles up to redline at times. I am using +10° at the time but it is still very loud at times so I want to go further with the positive timing. I have the impression the real influence is within the Overrun Fueling Cut Counter RPM Threshold table, but I still dont know what exactly this does.

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