What affects knock? (what makes a car knock)

[turbotalon1g]

Broad question i know, but i am getting knock in my sweet 16g, E85 car like crazy.

The only thing i can think of is that the DP is touching the T-case and that is why, but no matter what any roll below 4k and it will start to knock. :wetpants:

I usually do pulls from 2k upward.

I have the knock sensor activated after 40% throttle and above 3400rpm.

Thanks

Aaron

[DoughtCom]

I know with Evo's their knock sensor is super sensitive and you get phantom knock or whatever it's called. I get knock even after a DB Tune, and I've read it's from my downpipe gently tapping the cross member bar.

I would look into your downpipe if you think your tune is pretty strong. I don't know about 1G's or your knock sensor but I know that's what's causing my problems, the Evo knock sensor is more sensitive than a teenage girl on her period.

[twack]

I had the same issue and i knew it was phantm knock. For the time being i raised the knock peramiters. might not be the safest but car runs like it never ran before. damn knock timing pull

[123abc]

When my car is cold and I get slight lifter tick, the sensor picks that up and it sucks trying to drive untill it warms up past about 140-150, then no sign of knock at all.

[niterydr]

Ignition timing set?
Winter or summer blend e85? How old?
Any idea what your intake temps are?
What AFR are you at?
What ignition timing values are you seeing?
How do the plugs look after a pull?
How old is the knock sensor?
Any other engine noises?
How does the oil look?

Phantom knock doesn't exsist, the sensor is hearing something, weather it is a major deal or not is what you need to determine.

[turbotalon1g]

base timing is set to 5*
class 2 E85
Intake temps about 20 above ambient at most
Coolant temps at 179 at start of pull 183-185 after
mid to low teens for timing values
oil looks fine as do plugs. Using BPR7ES plugs
Knock sensor age unknown

[Halon]

I'd first try to determine if it's real or "phantom" knock. Put some race gas in there and see if the knock is still present, or if it goes away. If it goes away, then you probably are experiencing real knock. If the problem is still there, then it's the so called "phantom" knock. I'd say that is the first step.

[turbotalon1g]

^ok, i didn't think about that since i am using \\\\\\\\\\\\\\\\\\\\\\\\\e85 or at least the current blend.

[Halon]

I forget you're on E85, sorry. That's basically a race gas in itself.

[niterydr]

Pull 3 or 4 degrees of timing and see if it goes away.