Knock sensors and semi-solid mounts
Thread Starter
Instructor
Joined: May 2009
Posts: 137
Likes: 0
From: Maryland
Knock sensors and semi-solid mounts
I have been reading about WEVO semi-solid mounts and there seem to be a lot of pluses to these. But I also have read a few scattered comments about the increased vibrations possibly affecting the knock sensors and therefore reducing engine power because of the possibly false knock readings. Does anyone have any real experience with this? Perhaps a dyno of before and after the mount installations?
Pro
Joined: Aug 2009
Posts: 590
Likes: 4
From: Houston, Texas, USA
Sounds implausible given all the cars that run solid engine mounts. I would discount any but first person accounts, and I would take those with a grain of salt minus hard data that can be repeated and verified independently.
RL Technical Advisor
Joined: May 2001
Posts: 11,870
Likes: 75
From: Portland Oregon
I have been reading about WEVO semi-solid mounts and there seem to be a lot of pluses to these. But I also have read a few scattered comments about the increased vibrations possibly affecting the knock sensors and therefore reducing engine power because of the possibly false knock readings. Does anyone have any real experience with this? Perhaps a dyno of before and after the mount installations?
If someone is experiencing a power loss issue, there are plenty of places to look at besides this one that will yield the source of the problem,....
Nordschleife Master
Joined: Dec 2001
Posts: 8,305
Likes: 16
From: Kingston, NY
I can tell you from my testing of knock sensors and MoTeC ECUs, that solid engine mounts can affect the engine noise and therefore the signal to noise ratio that the knock sensors are reading. In some cases it requires sampling on a different frequency. For instance, testing on a Chevrolet V8 engine with and without solid engine mounts showed a difference to the point where the knock sensors would not properly function with the solid engine mounts ON THE SAME SAMPLING FREQUENCY as with rubber mounts. Moving the sampling frequency around allowed the knock sensor to function properly.
HOWEVER, I agree with Steve and haven't seen any issues with Wevo mounts on the 964 engine. Don't forget that the 964 Cup cars ran solid engine mounts without issue, although, I don't know if there is a difference in the knock sampling frequency. Perhaps Lorenb would know.
HOWEVER, I agree with Steve and haven't seen any issues with Wevo mounts on the 964 engine. Don't forget that the 964 Cup cars ran solid engine mounts without issue, although, I don't know if there is a difference in the knock sampling frequency. Perhaps Lorenb would know.
Thread Starter
Instructor
Joined: May 2009
Posts: 137
Likes: 0
From: Maryland
I can tell you from my testing of knock sensors and MoTeC ECUs, that solid engine mounts can affect the engine noise and therefore the signal to noise ratio that the knock sensors are reading. In some cases it requires sampling on a different frequency. For instance, testing on a Chevrolet V8 engine with and without solid engine mounts showed a difference to the point where the knock sensors would not properly function with the solid engine mounts ON THE SAME SAMPLING FREQUENCY as with rubber mounts. Moving the sampling frequency around allowed the knock sensor to function properly.
HOWEVER, I agree with Steve and haven't seen any issues with Wevo mounts on the 964 engine. Don't forget that the 964 Cup cars ran solid engine mounts without issue, although, I don't know if there is a difference in the knock sampling frequency. Perhaps Lorenb would know.
HOWEVER, I agree with Steve and haven't seen any issues with Wevo mounts on the 964 engine. Don't forget that the 964 Cup cars ran solid engine mounts without issue, although, I don't know if there is a difference in the knock sampling frequency. Perhaps Lorenb would know.
Interesting. This installation would be on a 2008 Cayman S. What would be the process of testing to tell before and after if there is a problem?
