knock knock...

[Clipse]

Trying to tune my new setup and I'm getting around 6-13 counts of knock at WOT. The car isn't running lean nor rich. I run 92 octane at all times. My current setup is 14b, stock 450s, Walbro 255lph, Buschur/SX AFPR, SAFC, MAFT w/3" MAF blowthrough, FMIC, 2.5-3" DP, 3" catback, MBC at 16psi

For example in 3rd gear WOT:
3800 rpm knock= 13, Timing= 12, o2v= .86v, Airflow= 1266 Hz, Inj. P/W= 17.95 ms.

5000 rpm knock= 14, Timing= 14, o2v= .88v, Airflow = ~1720hz (little high), Inj. P/W= 20.51ms

6500 rpm knock= 9, Timing= 17, o2v= .90v, Airflow = ~2000hz (little high), Inj. P/W= 17.95ms

What could be causing this knock?

 

[vlaar]

You're about maxed out on your 450's. If it were me, I'd personally throw in some 650's. Then you can play with your fuel curves more.

 

[Blk_99gst]

You're about maxed out on your 450's. If it were me, I'd personally throw in some 650's. Then you can play with your fuel curves more.

I first read Clipse's post and I thought 14b, decent psi; He's probably heatsoaking and getting knock that way. Then I say the FMIC in your list. Couldn't think of much after that, so I didn't post because I had nothing good to suggest.

But replying to vlaar's post; Yes Clipse could really benefit from bigger injectors, but I don't think this mystery knock he is getting from using the 450's; I could be wrong though. If anything, since he is using the stock injectors, the ecu is seeing the actual air flow and should be using very conservative timing numbers because it is not getting an altered air flow signal (I'm assuming that you have your maft set to zero's since you're using the stock injectors). So the ecu should be using very conservative timing advance, that conservative timing advance is there to prevent knock. I could see if he was getting knock because he had 660's in there and the ecu was giving too much timing because it was using the altered air flow signal.

Anyway, I hoped I didn't ramble too much and you can understand what I was saying.

 

[Clipse]

Actually, I have my WOT settings on the MAFT leaned out about 30% MID about 25% and the Idle is richened up about 20%. When I had it zeroed out the car was running insanely lean at idle and hitting fuel cut from being so rich up top. On top of that I have the Hi Throttle settings on my AFC at -9 to -10 across the board and the Lo Throttle at +7 to +9.

 

[kpt4321]

Fix your boost leaks.

The only reason you would need to lean it out that much under boost, and richen it up that much at idle, is if you had boost leaks.

 

[Clipse]

Fix your boost leaks.

The only reason you would need to lean it out that much under boost, and richen it up that much at idle, is if you had boost leaks.

I will check into that... Thanks!

 

[Clipse]

Could lowering my base timing a couple degrees be a possible fix for the knock?

 

[Clipse]

Really need help with this, getting as high as 25 counts now!!!

 

[vlaar]

Your settings on the WOT seem a bit high. Richen it up a bit and see what happens. Or you could just get H20 injection or alcohol injection like me Just kidding!

 

[kpt4321]

If you're knocking, then tume the car until it doesn't any more. It's that simple. Add fuel, unless you are maxing out the injectors, in which case you need to turn the boost down.

Get bigger injectors. Someone already suggested it.

Pressure test the car, someone also already suggested that.

 

[dthquazi1]

Yeah make sure you check for leaks. It souded like you had some when you got the second mas in there. And most likely it would be from the TB

Brett.

 

[Bohrn]

also, you may have excessive carbon build up in your combustion chambers. I hve this and no amount of tuning will get rid of it. I have plenty of fuel, and a front mount. Race gas took care of the knock completely.

 

[Clipse]

I have larger injectors I could put in but they're 750s and I wouldn't think those would work well with a 14b...

I did however just look at one of my logs and even with the my WOT set at -20 my injector D/C was 105%

Can my car be running lean even though the the o2v is only reading .88v? Sorry for the newb q but I really don't know.

 

[Clipse]

Yeah make sure you check for leaks. It souded like you had some when you got the second mas in there. And most likely it would be from the TB

Brett.

Were you there when Demico and Nick were changing out my MAF for me on Wednesday?

 

[dthquazi1]

yeah and if you listen it kinda sounds like a leak is somewhere. I didn't have much time to listen but i thought i heard a small hissing. Also did you get the idle problem fixed when you did the o-ring. It had the worst idle.

 

[Bohrn]

Clipse, try the 750's. With the MAFT, not only do you have a big ass maf, but you have baseline tuning for your injectors. It will let you run those fine. I run bigger injectors with a 2g maf and its fine, I passed aircare really well.