What does Feedback Knock & DAM actually mean? | Subie Talk episode: 2

[@styrex4261]

thanks a lot for this. I’m tuning my 04 myself and it’s always nice to know what’s real knock and what i shouldn’t be too concerned with. Btw, for the older generations, pre 04 or 05, the ideal dam is 16, since the ecu is a 16bit computer.

[@markayala]

this is what I call high quality content

[@boostnboba7658]

If your scared just unplug your Cobb. Problem solved ;)

[@chrisconnolly8905]

Boost'N'Boba ummmmmmmmmmmm

[@codeezy__]

Trump logic on the virus cases 😂

[@naddz12345]

Anxietyport

[@barsaf9989]

Literally did this. I was constantly worried about the different readings. The car is running fine. Nbd I'm not pushing a lot of power.

[@apreviousseagle836]

@@codeezy__ Trump unplugs his Cobb unit when there are virus cases?

[@jons4686]

My DAM is consistently at 1.0. I get feedback knock over 12 shifting between 1st and 2nd. Pretty sure its the loose heatshield on my uppipe triggering the knock sensor. I have never seen feedback knock while WOT. Anyways my Accessport is in the glove box. It does suck though that the ECU pulls boost and timing when this occurs. I can actually feel it when it happens. I bought a ceramic coated uppipe from Grimspeeed to remedy the problem but still haven't gotten around to installing it.

[@logantoler5049]

Thanks for the info , my 13 hatch hits 11.8 every time I drive only happens when I’m in 5th gear but the DAM never drops

[@Kradle]

Something I'm suspecting with my '16 VA right now is that I was running ethanol free 93 on and off for the past 6 months. Saw DAM drop for the first time a few weeks ago and so I switched to 93 e10. I'm seeing ALOT less knock but DAM hasn't come back up yet - I'm trying to avoid resetting the tune to see if it'll correct itself overtime after running better 93 through the car. I suspect ethanol free 93 is more like 89 octane. These Subaru's force you to learn about your car and it's stressful but I love my wrx

[@WillyQ60]

My DAM went down to a 0.250, the knock is perfectly fine, the car runs perfectly fine too, I’ve used different gas station too and it hasn’t changed

[@satoshibautista7766]

I can't find anything on the DAM being high. But I decided to watch it on the access port and it doesn't move from 16. Got anything. It's a 02 wrx EJ205

[@jessec.7047]

I seen -7.00 last night when i passed over the double yellow rimble strip at passing speeds but my knock learn never changed or my dam

[@ethan_stire3281]

Jesse C. That’s a perfect example of how that system is not that advanced and it picked up a vibration from an outside source

[@gerapadilla8989]

I was going up hill behind a semi on high gear and slowed down then bam 💥 -7.00

[@automattic6829]

Thanks for the vid! I recently went stage 2 on my 04 Forester XT and am seeing consistent Feedback Knock Correction of -9.00 above ~4700rpm during WOT logging. DAM stays at 1 and Fine Knock Learning stays at 0. Any ideas?

[@ethan_stire3281]

autoMATTic hmmmm that seems interesting. I’d want to say it’s a false reading but if it’s consistent then that wouldn’t be the case. Might be time to look into getting a tune from a reliable shop or sending your data logs to Cobb with that same question

[@TrafficsKindaBad]

2002 and before DAM is 0-16 or 1-16, I think I read from cobb.

[@kronic12052]

05wrx ecu here and DAM is 16, think it changed in 2006

[@defaultdaniel]

Good / insightful video. Just went Cobb OTS Stage 2 map on my new 18 STI (2k miles). Stock except an invidia catted downpipe and r400 catback. I will say it is very common for feedback knock / fine knock learn to hit -1.4 or -2.8. They never exceed -2.8, and my DAM stays at 1. Kind of through me for a loop at first, as I thought something was wrong, but I guess it's very normal (Cobb sent me an email saying this too).

[@pungkwok1341]

I only get acn91 stage1+ on my 18 STI. Sometimes I do WOT the feedback knock will goes to 4.2~5.6(usually 4.2 ) only once went to 7! But DAM a Has still kept 1!

[@Cheesehead8776]

Winter blend fuel is a legit culprit for me. Every winter I have been getting DAM drop.on 93 protune. I'm having my tuner make a 91 tune for me to run for future winters. I witnessed this DAM drop over 2 winters straight. During warm months, car runs perfect...crazy shit..

[@JohnDrach]

I get -2.8 consistently while cruising at 80mph or above. Should I be concerned? As soon as on go below 80 it goes to 0

[@subieja]

Thanks for the video! I must just have put some shitty winter gas with my e30 blend, one day later got a 4.2 feedback knock and .35 fine knock leaning reading when on heavy throttle also DAM went to .891 and all I could think was, this gas has to be it, was fine before just needed to fill up at the same spot I always do 😞

[@krackheadplatano]

subie. ja how did it take for your dam to go back to 1 or what did you do for it to go back to 1, I’m having the same issues got some bad gas went from 1 to a 0.812

[@Hobson888]

If you get feed back knock but no change in Dam would you consider this result to be ghost knock?

[@ethan_stire3281]

Not necessarily. You can had an actual knock, but not bad enough to warrant your DAM to make a correction. Minor Knocks can/will happen from time to time

[@Kevin-gq2kj]

Would these values pick up rod knocking ?

[@cnpy2394]

My DAM went from 16 to 8 throughout 1 day and it was throwing feedback knock progressively got worse got home shut the car off I did get shell 92 might be a boost leak

[@sopadesopita]

my DAM drops to 0 on 93 maps even on LWG. the DAM hasn’t dropped since i switched to the 91 map LWG… hoping it’s just bad 93 gas.

[@martinruiz3539]

Ok so mine had a consistent reading of 0.5 on the DAM and the Feedback was reaching around -2.8 -7.0. The knock learn would reach a -.35 when I shift at about 3k rpm. I’m scared. Should I be ?

[@Geeoh392]

Thanks so much for this video. Very informative, i was so scared. I have a 2008 STI and Yesterday my feedback knock read -2.80 and DAM went to 0.812 and i had no idea what to do. My car was bogging out so i read the codes on my AP and turned out my MAF was acting up, im looking to replace it soon but in the meantime i got some MAF sensor cleaner, cleaned it up and my car started running like normal again. My DAM went back to 1 but my feedback knock hit in the 2.0 zone again this morning. Not sure if i should be concerned or not 😭

[@ethan_stire3281]

STI.nkeye • sounds decently normal. You can try switch gas stations to see if you got some bad gas. As long as it stays 2ish or lower you should be alright

[@Geeoh392]

ETHAN_STIRE well thanks for the video and reply man! I appreciate it!

[@Geeoh392]

ETHAN_STIRE and just this morning my feedback knock went to -3.85 🤦🏻‍♂️

[@Mamba4Lifee]

STI.nkeye • did you ever change the MAF sensor? Or ever fix your issue? I’m having the same problem lol

[@anthonyguzman48]

What was the fix??

[@fredapol88]

Hi was just wondering if DAM drops during launch control?. I was testing my launch control yesterday and my dam dropped to 0.25. No fbk registered tho. Prior to that my dam always stays at 1 while my fbk usually on a range of 1.40 to 2.80. Once in a while 4.8.

[@Mamba4Lifee]

I’m having this issue now lol did you ever fix it??

[@Flossydope]

RichardUzumaki same

[@somersfamily]

Wish I knew my reason for crazy feed back knock at wot all of sudden . Got 14 gallons of gas from wah wah and 2 days later I hit a 11 and then a 5 and my dam went down and now I'm freaked cause when I get the knock I can hear like pinging or knocking its so loud. No problems with the car in 6 years, one mod, it's treated like a baby. So now I am not even going into boost until I figure out what the hell happened . Car runs fine and has no knock when the car is Idling. it runs absolute fine. Don't know what to think of this issue to be honest with you. I'm praying that it was really watered down gas and it really wasn't 93 octane and they screwed up and put some s*** in there. I really don't feel like spending 5 to 7 grand to build my motor on a car that I finally own that I've had no problems with in 6 years but very good. Also I may add I try cleaning my mass air flow sensor, new air filter the air filter, My spark plugs were changed 5 or 6 months ago though and I always use premium 93 octane on a stage one tune from MA performance. I even flashed it back to stage 0 so I can just monitor and watch it in the meantime and it still does the same d*** noise I got about a 1/2 a tank left so unhopefully I'm gonna run it all the way out fill up with some different shell gas octane booster and see if that works if not I guess I'll to take out the spark plugs and do a compression test and go from there( last I will add. I've never ever had any feed back knock at wot, only fine knock learn during low rpms and per some people I'm always gonna get some low feed back and fine knock learn in cruising . That's what mikey botti told me anyways .

[@caryg4638]

I know this is late, but gas station owners often will pump regular fuel in the premium tanks. Their rationale is that it makes them more money and you never notice, because of knock sensors. However, for the tuned cars, this is a big deal. Try sticking to Costco or BJs or Sam's as they typically have consistent octanes because they don't have a greedy owner siphoning one tank to the next.

[@MoJoNinjaGarage]

Just subscribed dude great video! I’m trying to learn more about Subaru’s,

[@creator4413]

I cant tell if i have rod knock or detonation motor only has 6k on it and forged pistons race bearings killer b oil pan always kept up on oil etc. So could it really be that? I feel like i got a combination of bad gas and i just discovered a vacuum leak and I feel like it might need a new fuel filter... getting very high fine knock learn but feedback knock always at least usually stayed at 0 but sometimes jumped up to 2 or 4. I started to be able to hear it today and ive never heard either one before so i dunno. If this engine is totally dead thats so much of my life wasted. Something is wrong though and im almost sure the motor is gonna have to come out ive literally just been fixing problems for a year and it was in the shop six months before that like when tf does it end? I cant even get rid of the thing now cause im like $40k deep. I might just have to buy a shor term beater car and save up for a while to fix it cause i can't really sell my bitcoin at this point id lose out on even more if i did that

[@edwinwhitmoyer3872]

So I have a 15 cvt stage 1 plus and my knock goes to -2 to -4 and my lean goes to -8 when I’m above 10psi and my dam is around .128 or .250 a lot pretty worried seeing if you can help

[@bryceenglish671]

If my access port isn't constantly reading say (-4.00) for example but it may pop up once or twice on a 10 mile trip should I be concerned?

[@bodiesbybradsfitnessbrad8621]

Hello on my 2018 WRX my accessport Knock sum is reading a 0/4 4 also saw a green light for a moment Feedback knock is 0.00 -1.41/0.00 Dam 1.000 fine knock learn 0.00/0.00 just had it pro tuned is this normal

[@blackspirtz1]

I have a few knocks while cruising but it never goes passes 2.81. It isn't a once in a blue moon type of thing. Happens pretty often for me. I have a 2017 wrx

[@ethan_stire3281]

Naib Chowdhury so the FA20 motors have a different readings than the EJ motors do. To be honest I’m not too familiar with what to be looking for on those motors. I know the concept is essentially the same but still different

[@blackspirtz1]

ETHAN_STIRE yeah people have told me that. The engine is much more sensitive and picks up more random noises. Thanks

[@ethan_stire3281]

I have heard that too. I do know that the DAM on the FA motors does have a tendency to change much more often that on the EJ motors too. Now I'm not sure if that is knock related like I talked about in the video of if a result of something else. I may look into it and make a video for all these new FA motors running around now

[@subedude]

Mine went to 0/-10.55 one time for just a little

[@pungkwok1341]

I have a 18sti, my feedback knock is sometimes around 4.2 . And if I pull from 3 gear to 4 gear(WOT) The knock sometimes goes to 5.4~5.6, onetime highest feedbacj knock is 7. I just using OTS map ACN91.

[@jameswright8193]

Pung Kwok did you figure out what happen? I have the same issue

[@Mamba4Lifee]

James Wright I’m waiting on this too I’m having the same issue lol

[@Flossydope]

Pung Kwok The exact thing is happening to my car! Mine never went to -7. Though. I don’t know if I should be worried.

[@Mamba4Lifee]

Flossy mine does that all the time, mainly in the heat. It happens less at night, do you have an Air Oil Separator?

[@Flossydope]

RichardUzumaki No I don’t, I’m just running the Cobb sf intake and the ACN91 sf stage 1 map.

[@tysoncoleman3285]

I just hit a -31.00 knock and my Damn was at .650. Pulled over took off the map then re-installed the tune and the car ran fine. Any thoughts?

[@Mamba4Lifee]

I keep having this issue, did you ever get it fixed?

[@tysoncoleman3285]

RichardUzumaki no but the car still runs 100% months later

[@Mamba4Lifee]

Tyson C damn lol ever since I got my block built I’ve had knock reading issues, car runs fine and got built at a very reputable shop, but for some reason just get knock issues. I do get a lot of blow by I’m thinking of getting an AOS

[@boostedrex9460]

Hey brother what if my dam is at 0.562

[@vip123-v4g]

Same with my 2016 WRX stage2 MAperfomance tuned

[@Menace_sti]

I got a 4.8 fbk and never went back to that number and my dam dropped to .50 for like 4 miles and went back to 1 again idk whats going on and i wasnt wot just cruising up to speed the car did jerk alil from a stop

[@Hello_its_me_mario]

Just seen my ap reading 19 on fine knock. What's the highest it can read?

[@Kradle]

False knock

[@cayzerjin128]

Is it fine if i got 4.8 feedback knock when just cruising, but it came back to 0?

[@DannyRomero-ds2mw]

Same is it sunning fine?

[@biggiej14]

What about negitive readings on knock feedback? Like -1.40 or -2.45 i have a 2011 wrx sti

[@ethan_stire3281]

biggiej14 so the readings should come through your accessport as a negative. That is my fault and I should have clarified that in the video. When I’m referencing a number I’m am referring to the “-1.40” number and so forth. So when I say 1.40 I’m meaning (-1.40/0.00) that would appear on the accessport

[@gamerfreak10210]

I’m concerned about my car because I get feedback knock ranging from 1.4-11.8 all at random times and my car never seems to have any noticeable issues or noise coming from the engine bay. My damn recently dropped to 0.062 from 1.0 I’m not sure what it’s all about. If anyone knows I’d really appreciate any feedback or advice? I changed my fuel to 93 but my car is a 91 octane tune rn, should I change that to 93 too?

[@nuttynate797]

Today my dam dropped to .875 and stayed there but didnt get any knock reading, is that weird?

[@derrickgarcia303]

What about Fine knock learn? How does it relate to DAM and Feedback knock.

[@Kradle]

Fine knock learn is the cars "memory" of fine knock - when it sees fine knock, it adds that to the fine knock learn data table and tries to see if it happens again at the same RPM range

[@wrxTO]

What could cause DAM ti drop and stay there? My DAM has dropped to 0.625 and I went through 3 tanks of gas still did not correct back to 1. Feedback knock and Fine Knock Learn are both 0 though. Only DAM is low. Its 2020 wrx all stock car just protuned. Yes, I asked my tuner but he couldnt figure out. He said its normal. But is it normal to be below for so long? Thanks!

[@hebegb1966]

Run some Royal purple boost octane through it. Within a tank it should clear up. I'd only get a DAM drop if I used crap gas. I use Shell V power 91 octane exclusively and no drop. Chevron is another gas that is recommended. Hope this helps. I have a 2020 also.

[@jeff666p]

Is a -1.4 feedback knock when getting on or off the gas quickly something to worry about?

[@nickbauer541]

That’s exactly what I saw on my 2011 sti today did you find out if it’s okay?

[@jeff666p]

DDAY541 I found my heat shields were loose. It helped a lot.

[@jaimegonzlaez8459]

i just installed my invidia catless down pipe and cobb sf intake on my 2010 wrx before i never has a issue but once i installed those mods i did a lil pull td to fell the difference and i got a 0.250 on my dam and it stays there i’m going to get dyno tune monday or tuesday do you think i messed anything up on my car ? i already re built the motor couple months ago i put forge pistons really hope i didn’t mess anything up

[@sollothrop4869]

can i ask if you discovered what is was? i just installed cobb stage 1 and my dam went to around .2 aswell im very new to all this and am not sure what to do

[@DonteTidwell]

this helped a lot. thanks

[@IMTheOnE1984]

0.70 concern or no?

[@CesarGonzalez-we5sp]

my Dam is never at 1 when i start the car it’s at 680 and i get 1.80 on knock sometimes

[@delaneyschafer2110]

Lol same. Mine is never at 1. It fluctuates between . 358 and .850

[@cayzerjin128]

What’s the issue if you have max feedback knock on FA motor?

[@hebegb1966]

If you're getting that consistently, bent rod is worse case on a FA 20. EJ moter ring failure?

[@techniqueracing8620]

So I’ve consistently been hitting 1.4-2.8 every drive and today hit 11.8 on the freeway, however I was accelerating in 6th gear in lowish rpm’s, the engine shook while it was reading that. Any ideas?

[@techniqueracing8620]

Also installed a stage 2 downpipe this week

[@Ecks520]

I think thats still a false knock. I have that happen occasionally too. If youre dam is still at 1, i would think you would be fine.

[@daily_driven_]

Just be careful accelerating at to low of rpm... just like on the white board high gear low rpm can give knock readings, but it can also cause stress on the engine that isn’t good, keep the rpms up before you roll into the throttle 🤙🏼

[@alex_vapenation1116]

I’ve been getting knock readings like -5.6 lately what could be the issue?

[@ethan_stire3281]

Alex_vapenation is switch gas stations to see if that changes anything. If it continues to happen you might want to consult a tuner

[@megak0n299]

great video

[@WikedWips]

Very good vid! Thank u

[@Lovell_STI]

Well shit i hit -12 on occasions... maybe i should stop driving it till i get it fixed lol

[@levilueth7778]

I get a -4.92 when I rev from idle, then it goes to 0.00 my DAM is at 12. I'm a noob don't crucify me. What do I look at to fix this?

[@stuna101a]

You need to get your car retuned. At WOT at 90° out, I get a 1.3, once and a great while a 3.8 on pump gas on the hwy

[@st8bustin]

Your fine

[@levilueth7778]

It was all due to the tgv deletes, I've been good since my tune. Had a dirty Maf as well and some up pipe leaks.

[@stuna101a]

@@levilueth7778 you should have almost instantly got a CEL, then when you checked the code it should have said TGV system error, or something similar. The Accessport really is an awesome tool for diagnostic and data logging.

[@stuna101a]

Remember these engines are almost 20 years old. Plus they're temperamental, especially when tuning.

[@elikinder1535]

My DAM is at 16 and shows 16/16 what does this mean I own a 02 wrx

[@st8bustin]

16 is good

[@jeremyjackson8643]

Nice video, explains everything real good. Could have done without the music...lol

[@alexbetancourt414]

I have a 2006 sti with 8.2 CP pistons. (noisy pistons) my DAM is steady at .500 My knock learning is always at 0 but sometimes to -2.00 Just for an eye blink

[@Mamba4Lifee]

I have an 07 with a built block too and I kept having the same issue where it would stay at .500 I changed my knock sensor and it slowly went back to 1.000 after like 60 miles of driving it

[@unprofessionaljedi]

I'm at -2.00 ~ 0.00 it normal right?

[@ethan_stire3281]

Tommy Tran if you DAM stays at 1 while the knock is reading anything other than 0 you are just fine. An that -2 is a very very range to be at

[@Teeterkid2]

Thanks bro

[@Moses.BBlogg]

My dam is at 0 and it’s not changing

[@remissiveslave]

Makes you almost want to just scrap these pos turbo 4 cylinder motors and stick with a v8.

[@floridaboyabroad]

What makes you say that? V8s have their own problems.

[@remissiveslave]

@@floridaboyabroad they don't require high compression aka less reliability to produce power. Simple facts, and there more robust