dannyj661

5.3 Gen III in a 62 impala. Single turbo. Do I need the knock sensors tied into the system or not.

Thanks

forcd ind

iTrader: (7)

I disabled mine, some use them, some don't-I may one day play with using them, if I learn how to tweak them

rotary1307cc

iTrader: (5)

Junk. Throw away

They are calibrated for completely OEM, that's it

Change anything, cam, valve train, engine mounts, exhaust, Perty much anything and they are worthless

stevieturbo

There are settings within the software to allow the user to calibrate them correctly though ?

IMO it's senseless to throw them away. By all means turn any controlling action off if you are unsure how to set things up correctly, but there is no harm having there and logging information when you want.
Then you can set things up correctly, again up to whoever is tuning it how much correction they allow if any noises are heard.

redbird555

iTrader: (14)

gm spends so many hours calibrating those things to work with a specific combination that really when you modify the cam, exhaust etc they get thrown off so even with bolt ons they're out of whack.

I have messed with the sensitivity settings and found that if you leave them stock they dont pick up much of anything with the increased noise from mods but if you start increasing sensitivity there isnt really a happy medium. either they pick up nothing at all or they pick up all sorts of false knock and cause issues.

rotary1307cc

iTrader: (5)

Yup truth

dannyj661

Thanks guys, appreciate it and look forward to not using them.

Blown06

iTrader: (32)

I don't use mine. Lots of noise with a solid roller though.

forcd ind

iTrader: (7)

I know they moved them from the valley to the block somewhere, was that to try and get away from engine noise, make them read engine "pain", lol, better

stevieturbo

I use knock sensors on mine, and it works fine...but I'm not using an OEM ecu

Shownomercy

iTrader: (1)

Mine is there but not doing much other than keeping the water in the block. lol

69-chvl

iTrader: (11)

Would engine knock or pings be less "noisy" as compared to all the other noise? If so, then the knock sensors would be useless. If not, why not at least try?

redbird555

iTrader: (14)

knock sensors are calibrated to listen for one specific noise on a very fine frequency. when you change the location with sensors that werent calibrated or made for it they will pick up all sorts of excess noise and not pick out the pinging noise.

sure everyone is free to try. I did. After talking to katech and slowhawk though I decided to stop messing with them as I had the same issues they did

stevieturbo

Knock sensors on modern cars are generally wideband sensors, they simply listen over a wide range.

The ecu then filters this out, listening more closely to certain frequencies, and in better systems only listening through a specific window of crank degrees on a per cylinder basis, again this helps with filtering out unwanted noises.

But it isnt just the frequency, it's also noise changes or patterns. Clearly background noise that's always increasing is of no concern, it's any loud spikes that are of more interest.

It will of course boil down to the ecu you're using, how configurable it is, and the person using it.

But as said, if they're there, it can do no harm to have them there simply listening. Again, it's up to the tuner as to any controlling action they allow based on what is being heard.

If you arent confident with the setup, just listen and dont try and correct anything.

RonSSNova

iTrader: (3)

I know a couple turbo guys who turned them off because they used solid mounts and the sensors talked at idle.
About 6 engines later, both went to forged bottom ends.

If you are hearing knock under high boost, the damage is done.

I've two hotrodded LS engines. One NA on gas, one turbo on E85.
Knock sensors are slightly desensitized, and set up to decay quickly. I see the knock, I never hear it. Trimming timing just ahead of where the KR occurs fixes it.

I think they are a good tuning aid. At least in my case.

Ron

oscs

iTrader: (19)

I don't use them

stevieturbo

Mines solid mounted and solid roller.

Knock sensor feedback works just fine, but again it does boil down to the ecu you're using and how configurable the knock detection, and subsequent knock control you allow it.

Used correctly, good knock detection always makes sense....whether in the form of electronic devices, or the most basic, and arguably perhaps the best, a plain and simple stethoscope/det cans as they're more commonly called.
You can pick up even the slightest onset of knock with those, and it is always sensible to back up and configure any electronic means with the stethoscope.

The Alchemist

iTrader: (19)

I recently switched from an ls1 to an ls3 and moved mine to the sides of the block. I wasn't seeing any knock, ever, not even tip in or burst or any at all. So I began adjusting the sensitivity of them a little at a time. Granted, my tune is conservative, so I don't expect to experience knock, but it is a nice safety net. I continued to increase the sensitivity till I noticed an occasion 0.5-1.0 degree of knock detection during high load, high torque times. I then decreased the sensitivity by a little bit.

The way I look at it, is it's a safety net in case something goes wrong. If the build is done right, fuel source is consistent, and the tune is conservative, you don't have to worry, but show me someone who actually measures their octane each time they get gas? Mistakes can happen, so it's nice to have them as a backup. I don't tune based off them, but since I have them, I made use of them.

oscs

iTrader: (19)

I actually measure my octane every time i get gas BUT i rarely drive my car on the street.

stevieturbo

Exactly how they should be used. As a safety net if things do go wrong.

Of course their ability to pick up noise in conjunction with logging, can be helpful when diagnosing other problems. If you start seeing lots of noise for no reason and you know the tune is safe...then you might need to delve deeper into the engine.