Partial throttle knock or phantom knock, please help!!

[Stainbox12]

I´ve been dealing with this problem for a while, im not sure, what is caussing it. I haven´t replaced my knock sensor yet, but i would like to know, what can cause this. When my car is standing (not moving, just idling), i rev slowly, and i see no knock, but if i mash the throttle fast, i can see massive amounts of knock like 25 or 40 counts. Whenever im driving, and i boost, i can feel the car being pulled back, like timing is being retarded. Can compressor surge cause knock though? thanks.

 

[GVR4592]

It sounds like real knock to me. What octane fuel are you using?

 

[Stainbox12]

im using 95 Octane gas. Isn´t phantom knock when you just rev the engine in neutral? and crazy knock counts come up?

 

[GVR4592]

Phantom knock can be any activity detected by the knock sensor that isn't actual detonation.
Have you checked your base ignition timing? It should be at 5 degrees BTDC.

 

[Stainbox12]

Yes, its at 5 BTDC. I guess i would need to pull my engine out. To find out if its real or phantom knock. I would need to do it anyway, since my block needs oversized pistons. I do have 120 compression in 1 cylinder, and 150 across the other ones, im wondering, if that is caussing my knock.

 

[Bmxr152]

You can try the $40 phantom knock tester. What you do is use all the gas in your tank and then fill it up with some VP, sunoco race gas with a octane higher than 100. If you still have high counts of knock then for sure its mostly REAL knock. Phantom knock can be cause by many things like a blown knock sensor, too tight knock sensor, too loose knock sensor, some kinds of lifter tick, so there are many possibilities for phantom knock.

 

[DallasN2O]

If you still have high counts of knock then for sure its mostly REAL knock.

If he still gets really high knock counts w/ 100+ octane race gas, wouldnt that mean its been phantom knock he's been getting?

 

[Stainbox12]

with race gas, if knock goes away, its real knock.