What affects knock? (what makes a car knock)
 

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

Re: What affects knock? (what makes a car knock)
 

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.

Re: What affects knock? (what makes a car knock)
 

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

Re: What affects knock? (what makes a car knock)
 

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.

Re: What affects knock? (what makes a car knock)
 

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.

Re: What affects knock? (what makes a car knock)
 

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

Re: What affects knock? (what makes a car knock)
 

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.

Re: What affects knock? (what makes a car knock)
 

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

Re: What affects knock? (what makes a car knock)
 

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

Re: What affects knock? (what makes a car knock)
 

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

Re: What affects knock? (what makes a car knock)
 

You need colder plugs with E85.

Re: What affects knock? (what makes a car knock)
 

There is hardly any timing in it, its pulled pretty bad.

Really? colder plugs? i thought BPR7ES would be fine cause E85 burns colder i thought a warmer plug would suffice, but i guess i will try 8s.

Thanks guys.