Someone relieve me of my ignorance, please

[futurevr4man]

Mine has quite a bit of knock frequently when pulling away from stop lights. If an engine has slightly loose tolerances (like mine... Most race engines are built like that) then they tend to be a bit 'noisier' as far as the knock sensor is concerned and will show some knock. It's annoying, but nothing that should be worried about. I may play with the filter on my knock sensor a bit but it will be in the future after I feel like I know tuning inside and backwards.

[futurevr4man]

And Kevin, like I said, it's interesting there is a coorelation between your duty cycle and the phantom knock you get... I wonder if it is repeatably more with more duty, or if you just happened to notice it once.

My first post was mainly to explain how the knock sensor works. Once you understand what is going on mechanically and electronically, the rest is fairly common sense

[RealMcCoy]

I'm going to be the dissenting opinion here, and theorize that it is in fact showing that much knock...

Under very light load is where the timing is at it's max, and the mixture is lean... Those are the conditions that will light off pre-ignition. Take any old V8 and start feeding it enough timing to make it start pinging, and check under what driving conditions it pings...

You can check if it's real knock or not without chasing down race fuel by just yanking some timing out of it and see if it goes away....

Are you getting a flashing alert on your LCDBC? or is that just the max recorded?

What spark plugs are you running?

I second the idea of verifying base timing.

[Primus101]

Hey Kevin, My '93 TT was having the symptoms prior to rebuilding it(9b's)- 28 count after going into 2nd, no load-granny driving.

A few things I attributed to it once the motor was apart-

The knock sensor was leaking & was replaced-
The knock sensor bracket>block had shitty contact patch area-

The main bearings were dangerously at the end of their life-

Never did it again with my 13c's after rebuild.

[j2k4]

I'm going to be the dissenting opinion here, and theorize that it is in fact showing that much knock...

Under very light load is where the timing is at it's max, and the mixture is lean... Those are the conditions that will light off pre-ignition. Take any old V8 and start feeding it enough timing to make it start pinging, and check under what driving conditions it pings...

You can check if it's real knock or not without chasing down race fuel by just yanking some timing out of it and see if it goes away....

Are you getting a flashing alert on your LCDBC? or is that just the max recorded?

What spark plugs are you running?

I second the idea of verifying base timing.

Been looking for my timing light for three days...

I forgot to mention about the alarm - I have yet to get the flashing display, but I get the tone real early - maybe passing 4K at 7psi - I had my audible alarm settings at 10 for knock and 235 for temp, so I'm pretty sure something is wonky, there - the numbers just don't correlate, and frankly, I'm not paying attention to it at the moment.

Plugs are whatever stockers should be, platinum-specie - got 'em from 3SX, but can't remember the number.

Hey Kevin, My '93 TT was having the symptoms prior to rebuilding it(9b's)- 28 count after going into 2nd, no load-granny driving.

A few things I attributed to it once the motor was apart-

The knock sensor was leaking & was replaced-
The knock sensor bracket>block had shitty contact patch area-

The main bearings were dangerously at the end of their life-

Never did it again with my 13c's after rebuild.

Waiting on my Blackstone results, too, so that may shed some light.

There's a good chance I should, just for the exercise, pull the plenum and check/replace the sensor and peek at the plugs, but I'm betting, absent some sort of breakthrough, I won't do that until I park it for winter.

You know how that goes...

[HLxDrummer]

You said it knocks bad with basically no load? My car has always knocked with moderate load/low RPM (climbing a hill without dropping a gear). I have come to the conclusion this is normal although I do try to avoid it (back off the throttle or downshift). When the engine is under low load knock isn't as damaging from what I have gathered. Low/no load with knock is strange though!

[j2k4]

You said it knocks bad with basically no load? My car has always knocked with moderate load/low RPM (climbing a hill without dropping a gear). I have come to the conclusion this is normal although I do try to avoid it (back off the throttle or downshift). When the engine is under low load knock isn't as damaging from what I have gathered. Low/no load with knock is strange though!

That's my take on it, too, for the most part.

My dealing with knock, historically, is knock I could hear, going back to my V8 days, and always with pure mechanical compression, not power-adders.

This is still very new to me, and added to the paranoia these cars breed owing to their normal fragility, I'm gonna find out everything I can.

[Boost4VR4]

I think perhaps this is one reason why I am thinking of not using a knock sensor with my build... My spare engine doesn't have a knock sensor currently, so maybe run without one?!

[j2k4]

I think perhaps this is one reason why I am thinking of not using a knock sensor with my build... My spare engine doesn't have a knock sensor currently, so maybe run without one?!

I don't think I'd run a pressurized motor without a sensor of some type, Kev.

Be nice to find one compatible with our controls that was more foolproof and reliable.

[j2k4]

I'm gonna put it on a hoist tonite or tomorrow to check for knock-gremlins and I'll take a peek at the timing while I'm at it.