View Full Version : k20z1 jrsc knocks at 7800-8400 rpm

09-08-2008, 11:22 PM
as the title say, i have k20z1 supercharged running 5-6psi and i get knocks around 7800-8400 rpm. (i get atleast 3 knocks maybe 5 the most according to my k-pro) the car was tuned by professional tuner. he told me that it's probably ghost knock since he did a lot of adjustments but couldn't get rid off of the knocks. my questions is.>>> if it's real knocks is there a chance the engine will blow or it will just worn out faster? my tuner said as long as i dont get more than 10 knocks i will be alright since he double checked everything already and he is 100% sure it's probably ghost knock. the car is running really nice and it pulls hard but the engine light blink everyime i get to 7800-8400rpm on 3rd,4th,5th gear.

09-09-2008, 06:02 AM
get a good datalog of it and look at the voltage for the knocks. it could be phantom knock, but being that it is that high in the rpm range you really need to be sure. the jrsc does create a little bit of excess noise that is sometimes picked up by the sensor, but i have usually seen it in the lower rpm range, i.e. 3K-4K rpm. if you post the datalog up on the site there are a few guys who can look at it and tell you if it is real or not.

btw, what numbers did you get with the z1 and the jrsc? this is a swap i am looking at when my a3 w/ jrsc takes a dump eventually.

09-09-2008, 06:06 AM
I have not seen ghost knock that high, but it could be, post up your calibration and a datalog.

09-09-2008, 11:36 AM
I get knocks every once in a while in 3rd & sometimes 4th gear right around 5-6k RPMs. Jeff tried everything he could to get rid of the knocks and finally determined that they had to be phantom knocks. Just like what was mentioned above the JRSC makes plenty of noise and our knock sensors are super sensitive.

09-09-2008, 04:48 PM
i dont have a laptop to do a datalog. it's funny coz when i have my a3 with supercharged (same set up) i dont have any knocks at all and it's same guy tuned the car. i went to clubrsx and some guys has same problem but everyone said it's probably ghost knock since it's not more than 10 knocks. i used to get knocks from 4000-5000 rpm but when i upgrade my plugs to denso ik24 the knocks at that rpm was gone but still getting knock at 7800-8400rpm.