Knocking problem
Thread Starter
Heel & Toe
Joined: Aug 2008
Posts: 20
Likes: 0
Knocking problem
Hello from Finland
Need some help to solve my knocking trouble. My current LS 1 setup is Stage II ProCharger System ~9psi boost, AFR 205cc, Methanol Injection (50/50), 60lb injestors, Racetronix fuel pump, 1.85:1 Rockers, LG Super Pro Headers, Custom 3" catback and stock bottom. Using 98 (oct) fuel.
We was tuning my car last week and HP tuner was showing knocking on +3500 rpm and/or immediately after when boost starts to build up.
Just tried to calculate my compression ratio and i got roughly 10.3:1.
using 0.045 MLS geskets. Is my compression ratio too high?
Need some help to solve my knocking trouble. My current LS 1 setup is Stage II ProCharger System ~9psi boost, AFR 205cc, Methanol Injection (50/50), 60lb injestors, Racetronix fuel pump, 1.85:1 Rockers, LG Super Pro Headers, Custom 3" catback and stock bottom. Using 98 (oct) fuel.
We was tuning my car last week and HP tuner was showing knocking on +3500 rpm and/or immediately after when boost starts to build up.
Just tried to calculate my compression ratio and i got roughly 10.3:1.
using 0.045 MLS geskets. Is my compression ratio too high?
Le Mans Master
Joined: Jan 2009
Posts: 7,767
Likes: 19
From: East Texas
Hello from Finland
Need some help to solve my knocking trouble. My current LS 1 setup is Stage II ProCharger System ~9psi boost, AFR 205cc, Methanol Injection (50/50), 60lb injestors, Racetronix fuel pump, 1.85:1 Rockers, LG Super Pro Headers, Custom 3" catback and stock bottom. Using 98 (oct) fuel.
We was tuning my car last week and HP tuner was showing knocking on +3500 rpm and/or immediately after when boost starts to build up.
Just tried to calculate my compression ratio and i got roughly 10.3:1.
using 0.045 MLS geskets. Is my compression ratio too high?
Need some help to solve my knocking trouble. My current LS 1 setup is Stage II ProCharger System ~9psi boost, AFR 205cc, Methanol Injection (50/50), 60lb injestors, Racetronix fuel pump, 1.85:1 Rockers, LG Super Pro Headers, Custom 3" catback and stock bottom. Using 98 (oct) fuel.
We was tuning my car last week and HP tuner was showing knocking on +3500 rpm and/or immediately after when boost starts to build up.
Just tried to calculate my compression ratio and i got roughly 10.3:1.
using 0.045 MLS geskets. Is my compression ratio too high?
Thread Starter
Heel & Toe
Joined: Aug 2008
Posts: 20
Likes: 0
Thread Starter
Heel & Toe
Joined: Aug 2008
Posts: 20
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The valve sounds are same regardless of any RPM. Yes just picking up on HPT. We tried to adjust the knocking sensors to less sensitive but nothing works. Dont want to turn them off before i can make sense where is the knockin coming.
Burning Brakes
Joined: Mar 2008
Posts: 983
Likes: 36
From: Middle Of Kali CA
Hello from Finland
Need some help to solve my knocking trouble. My current LS 1 setup is Stage II ProCharger System ~9psi boost, AFR 205cc, Methanol Injection (50/50), 60lb injestors, Racetronix fuel pump, 1.85:1 Rockers, LG Super Pro Headers, Custom 3" catback and stock bottom. Using 98 (oct) fuel.We was tuning my car last week and HP tuner was showing knocking on +3500 rpm and/or immediately after when boost starts to build up.
Just tried to calculate my compression ratio and i got roughly 10.3:1.
using 0.045 MLS geskets. Is my compression ratio too high?
Need some help to solve my knocking trouble. My current LS 1 setup is Stage II ProCharger System ~9psi boost, AFR 205cc, Methanol Injection (50/50), 60lb injestors, Racetronix fuel pump, 1.85:1 Rockers, LG Super Pro Headers, Custom 3" catback and stock bottom. Using 98 (oct) fuel.We was tuning my car last week and HP tuner was showing knocking on +3500 rpm and/or immediately after when boost starts to build up.
Just tried to calculate my compression ratio and i got roughly 10.3:1.
using 0.045 MLS geskets. Is my compression ratio too high?
Melting Slicks
Joined: Mar 2005
Posts: 2,225
Likes: 42
From: Okinawa
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Tech Contributor
Joined: Apr 2007
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From: Forney Texas
Teme, is it showing up as knock retard or are you just missing timing? Your trouble could easily be mechanical. Could be a noisy valve train from your 185 rockers. We run more boost than that with more timing on equal compression motors and 93 or 91 octane. If you pull timing and it doesn't go away, you have some work to do. I don't recommend desensitizing your sensors either. Were they torqued properly?
Le Mans Master
Joined: Jan 2009
Posts: 7,767
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From: East Texas
you heard what your step daddy said (blue) 
Thread Starter
Heel & Toe
Joined: Aug 2008
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Thread Starter
Heel & Toe
Joined: Aug 2008
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Burst knock doesn't show up as normal knock. You simply don't get your commanded timing and don't show knock retard.
Teme, is it showing up as knock retard or are you just missing timing? Your trouble could easily be mechanical. Could be a noisy valve train from your 185 rockers. We run more boost than that with more timing on equal compression motors and 93 or 91 octane. If you pull timing and it doesn't go away, you have some work to do. I don't recommend desensitizing your sensors either. Were they torqued properly?
Teme, is it showing up as knock retard or are you just missing timing? Your trouble could easily be mechanical. Could be a noisy valve train from your 185 rockers. We run more boost than that with more timing on equal compression motors and 93 or 91 octane. If you pull timing and it doesn't go away, you have some work to do. I don't recommend desensitizing your sensors either. Were they torqued properly?
It is showing up as knock and it pulls the timing -6 and the car stops accelerating. Haven't touch the sensors. So do u think that i'll need to change the rockers back to 1.7:1? Planning to change A&A corvette stage 4 cam next winter and use 185 rockers on that cam.
Melting Slicks
Joined: Feb 2001
Posts: 3,376
Likes: 4
From: Hershey, PA, USA
Cruise-In VI Veteran
St. Jude Donor '12
Had this exact same problem. I'm positive it's valve train noise. I would get 2-3* timing pulled no matter what I did, had the timing down to 8* and would still pull timing. I am running Yella Terra's w/ Comp Cam R lifters.
Finally I put a tank of Sunoco 100 and left the timing @ 8* and it STILL pulled timing. So I knew it was false knock. I just detuned them alittle, I agree w/ not turning them off all together. There is a table in HPT that allows you to change the senstivity once you go over a certain RPM.
Finally I put a tank of Sunoco 100 and left the timing @ 8* and it STILL pulled timing. So I knew it was false knock. I just detuned them alittle, I agree w/ not turning them off all together. There is a table in HPT that allows you to change the senstivity once you go over a certain RPM.
Melting Slicks
Joined: Mar 2005
Posts: 2,225
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From: Okinawa
Melting Slicks
Joined: Mar 2005
Posts: 2,225
Likes: 42
From: Okinawa
Le Mans Master
Joined: Oct 2005
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From: Metro Detroit Michigan
Melting Slicks
Joined: Mar 2005
Posts: 2,225
Likes: 42
From: Okinawa
Didnt know they had a different calc than us. Heard they didnt use eathonal in their fuel though. I wonder what stoc is over there.
Thread Starter
Heel & Toe
Joined: Aug 2008
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No it wont run, i can rev up on first gear to +5000rpm about 15 percent throttle. Havent tried second, third and D. I hav A4 Transmission.
If i start accelerating from 2000rpm fourth gear, it lets me to up to 3500rpm. After that HPT shows knocking and computer starts to pull down the timing.