Audible knock at medium/ high load at low rpm

[JPGC]

Hello Everyone,
The weather here in Florida has been nice and as a result, I have had my windows down more so I now can hear my engine a little better vice when I have the windows up with the a/c on. Normally, I drive fairly light and slowly but when I do drive aggressively, I usually don't go medium to wot throttle until 3k+ rpm's. With that said, this morning, I was on an on ramp in 3rd gear at around 2300 rpm and had to speed up quickly, so I pressed the gas pedal down about 3/4 of the way in 3rd at 2300 rpm's. I hear the turbo spool, then I hear the engine ping/ knock 3 times really quick. Now I know it's not good to get on it that low of rpm and I know it's not rare to see slight negative ign corrections with a high load/ low rpm situation.
So, me being me, I hooked up the accessport and brought up the gauges. I wanted to see if I could replicate the same as above. Sure enough, I did the same thing twice afterward, resulting in audible ping/ knock as well as negative corrections ranging from -1.5 to -6.0. I also tried the same with the Cobb Stg 3 (91 October) tune and still got the audible ping/ knock with negative corrections of -1.5. I Use 93 octane BP/ Exxon/ She'll fuels btw. I am on my stock plugs at this time. I do not recall hearing this with the NGK plugs, but I my have just no heard it.
I need advice/ opinions on this please and has anyone else experienced this. Is this common or something I should be greatly concerned over.. Thanks

 

[dyn085]

I haven't had any knock or negative corrections at all. Did Justin look any logs after you swapped back to stock plugs? If not then that would be my first thought. If he did then my thought would be a tank of bad gas if you haven't had this happen before.

 

[JPGC]

I actually swapped plugs during the tuning process to verify that the plugs weren't causing a ign correct issue that we were having. I also just checked the first dyno pull I did to see if the noise happened then (this is the one that spiked my torque to 285 WTQ for a hundred rpm). Sure enough, you can hear it when the dyno operator first goes WOT at around 2200-2400 rpm. This was a couple weeks ago and two days after I went back to the stock plugs. It was also on different fuel from a different station. I am going to put the NGKs back in and test...ugh

http://youtu.be/-w2k9_d41A4

 

[Sourskittle]

Maybe you pulled the same trick as me and put in some 87/89 oct and didn't reallize it. I thought it would impossible for me to do as well after 5+ years of ONLY having 93oct rides ( and always having at least one that needed 93 for the past 15 years ). But... I did. I'd recommend finding an E85 station and add 1 gallon of E85, then top your tank off with 93oct and see where your at.

 

[JPGC]

Maybe you pulled the same trick as me and put in some 87/89 oct and didn't reallize it. I thought it would impossible for me to do as well after 5+ years of ONLY having 93oct rides ( and always having at least one that needed 93 for the past 15 years ). But... I did. I'd recommend finding an E85 station and add 1 gallon of E85, then top your tank off with 93oct and see where your at.

Yeah, I read that thread that you posted, lol it happens to the best of us. I'm pretty certain that I have filled with the 93 as I'm am ocd when I get gas..if for some reason I did on accident though, I've been through 4 tanks of gas since ( I drive a lot). E85 is pretty scarce here in Jax...I've yet to find a station that has it. Is there a octane booster that you recommend that is readily available?

 

[Sourskittle]

People say torco ( or something like that ), is pretty epic as far as octane boosters go. I've never used it.

I'm dealing ya, I was about to do a compression test on the motor to see if parts were banging around in the bottom end because I couldn't stop it from knocking.

I can drive 30 miles in 3 different directions and find E85. Just none where I live ( lots of places with E0 gas though for boats/mowers ).

Just don't freak out yet, lol. I was about 58% freaked out. Going from a tune I thought was safe, to the same tune + a bigger intercooler, and getting crazy amounts of knock at low rpm with very little boost, i was really. ( crazy amounts of knock was like 2.3 corrections lol).

 

[JPGC]

Yeah, I'm about 62% freaked out, the car just doesn't want to fully cooperate with me, lol

 

[Sourskittle]

Is there no Sunco stations with 100oct around you either? I have 3 100 oct pumps within 15miles of me. Its just.... $10 per gal vs $2.69 per gal of E85 makes it an easy choice ( because I have a choice ).

 

[JPGC]

There is a Sunaco on Beach Blvd here. I will have to go by there to see what they have. It's crazy here in Jax with fuels. Even the stations who list E85 here on the E85 websites have discontinued selling it.

 

[Sourskittle]

I had one 1.5 miles from my house here... First place i went the day after buying the fist... They discontinued it too. I even emailed store corp. offices asking if they were looking to build in my area, lol.

 

[JPGC]

Well I drove all over Jacksonville today with no joy on the E85. I did, however, find a Sunaco with the 100 octane/ race fuel pump but I will not be using that as it looked like it hadn't been touch in years, lol. On a good note, I logged for about 60 miles of both interstate, WOT, medium acceleration and stop-n-go traffic with no knock or negative corrections. I was paying attention to the way I drove, ensuring not to drop the hammer under 2500 rpm. I need to make a habit of that type of driving. I think that the ridiculous driving of others here in Jax has caused me to want to shift early while I'm driving in traffic which puts me in the situation of being in too high of a gear at low speeds when I need faster acceleration and not enough time to shift down.

 

[Sourskittle]

Assuming you have no hard part, mechanical issues ( spark plugs, boost leaks etc ), there should be no reason at all to see knock like you described if the tune is correct. The car should learn to your driving, not the other way around, lol. While I do agree that the stock turbo can put an enormous strain on the rods/bottom end when you got wot at 2000rpms, it shouldn't be completely off limits ALWAYS due to the tune.

Justin can dial it out if you want him to... If you want him to. And like I said, this assumes nothing mechanically has changed or came loose. If you run 100oct or E25+ fuel and the knock goes away, it proves its not a noisy mount or broken ring land or anything else but un-favorable conditions in the combustion chamber for 93oct.

I'm sure Justin would not only be able to tune it out, he'd prob like the chance to do so. If you paided me for a safe tune, and the weather changed on us like it has lately and the car started running in unfavorable way, I'd dang sure want you to let me fix it so that eveytime you pull the trigger and see knock, you don't grit your teeth and think "dang that sourskittle guy", lol.

 

[JPGC]

Assuming you have no hard part, mechanical issues ( spark plugs, boost leaks etc ), there should be no reason at all to see knock like you described if the tune is correct. The car should learn to your driving, not the other way around, lol. While I do agree that the stock turbo can put an enormous strain on the rods/bottom end when you got wot at 2000rpms, it shouldn't be completely off limits ALWAYS due to the tune.

Justin can dial it out if you want him to... If you want him to. And like I said, this assumes nothing mechanically has changed or came loose. If you run 100oct or E25+ fuel and the knock goes away, it proves its not a noisy mount or broken ring land or anything else but un-favorable conditions in the combustion chamber for 93oct.

I'm sure Justin would not only be able to tune it out, he'd prob like the chance to do so. If you paided me for a safe tune, and the weather changed on us like it has lately and the car started running in unfavorable way, I'd dang sure want you to let me fix it so that eveytime you pull the trigger and see knock, you don't grit your teeth and think "dang that sourskittle guy", lol.

Oh I totally agree with you and I plan to send Justin a message on it tonight. I am also in no way trying to down the tune as my experience with Justin tuning it has been great...even with my stubborn ass car, lol. The fact is, I never logged under 2500 rpm's on the datalogs I sent him, so we would have never known if the issue was present.

 

[dyn085]

You shouldn't have to drive in a manner any different than you were driving when you were being tuned. I routinely get on it at a lower rpm with no knock yet whatsoever. Definitely get in touch with Justin and he can help pinpoint the issue. I still think it's just a bad tank of gas, but that's nothing more than an internet guess.

 

[JPGC]

You shouldn't have to drive in a manner any different than you were driving when you were being tuned. I routinely get on it at a lower rpm with no knock yet whatsoever. Definitely get in touch with Justin and he can help pinpoint the issue. I still think it's just a bad tank of gas, but that's nothing more than an internet guess.

I also agree with this as well. I use different gas stations near my house that sell different brands of gas, but who knows, they may be using the same tanker. I'm gonna start using stations on a different side of town as well. Reason is that my car specifically has been a pain in the ass to dial in in comparison to others that I read about using Justin's tune.

 

[dyn085]

Yeah, mine was pretty easy. Once my negatives were tuned out I haven't seen them since. I only use one gas station in my town, though.

 

[JPGC]

I just emailed Justin, so waiting patiently, lol

 

[JPGC]

WTH, so while waiting for Justin to reply, I decided to go out and do a few datalogs because I'm sure he will want me to. Today it is about 10 degrees F warmer than it was on the 4th. I am also on the same tank of gas as before. I did, however, clear the ECU, KAM and re-install the tune. I drove about 40 miles then, started logging. I tried to replicate it in 3rd and 5th. No joy, which is a good thing, I guess, lol. The car ran flawlessly and I was unable to log the car with the issue. All four cyl were 0 to +2.5 on the ign corr throughout the entire time/ drive. Only thing I can think of other than the outside temp is maybe I did get a bad tank of gas 3-4 tanks ago and now I'm finally starting to get the bad gas out, since I fill up at 1/4 to 1/2 a tank when I get gas.

 

[Sourskittle]

Warmer temps, less boost?

 

[JPGC]

Warmer temps, less boost?

Same boost readings...22 to 23 psi