SKFengineer

I've done a search and it seems like there are many different opinions on the topic. I would like to see if I can clear things up.

First is the Knock Sensor Module the same thing as a ESC module?

Next a quick background... Had a 305 TPI changed to 350 TPI. Changed knock sensor only to 350 sensor, now I lots of knock events when I have the scanner pluged in and I'm running hard through the gears. I've checked the easy basic stuff timing, making sure the headers aren't hitting anything, etc. and this is even with 110 race fuel and the motor is only 10.2 to 1 compression.

When swapping the knock sensor do I need to change to a ESC / Knock Module that matches the new 350 sensor since the orginal 305 module is still in the car?

Lastly just to double check myself... The ESC / Knock module is on the firewall behind the MAF and Fuel Pump relays next to the brake booster, correct?

3rdgenZ

iTrader: (1)

yes the knock module is the ESC. yes it needs to be replaced as well.
how tight did you tighten the knock sensor. if you over tighten it it will break the little crystal in it (thats what picks up the "knock"). the knock sensor should only be about as tight as a spark plug. that could be the reason. yes, the ESC module should be the little black box by the brake booster. on the fire wall.

also see if you can get a LT4 knock sensor. they'll alow more knock before pulling the timeing back.

SKFengineer

Thanks, I'll check on the LT4 module, and just for safety's sake I'll change out the knock sensor at the same time I change the ESC module. I'm not really driving the car this time of year but I'll try to update this post once I get the car on the road and test the new parts on the scanner.

3rdgenZ

iTrader: (1)

you welcome, its the LT4 knock sensor not a LT4 ESC. you'll need the factory L98 ESC.

Good luck, and keep us posted.

SKFengineer

Good catch... I was wondering how the LT4 module was going to work with my ECM. Many Thanks

anthony64ss

iTrader: (1)

You need to learn prom tuning. Sounds like your new performance motor is too hot for the stock l98 maf system. A new knock sensor isnt going to help if your fuel curves are already way lean to begin with.

And why would you want a sensor that allows more knock? You dont want knock-it breaks things. The sensor is just an aid for poorly tuned motors, dont let yours be one of them.

SKFengineer

I didn't want to make the first post too long so I didn't list everything I've done to the car but the PROM is far from stock.

Actually if anything the current PROM tuning is a little rich which is something else I've been playing with, this whole car is sort of my little hobbie. As for your other question about allowing more knock or pre-ignition, EFI performance cars are constantly flirting with knock events. Most tuners try to run as much timing as they can without going over however doing so means that every once in a while the engine will still have a pre-ignition event and when that happens the PROM will suck 10-15 degrees of timing or more away and it only increases the timing back slowly so it can feel like your motor falls flat on it's face.

It's not so much that you slow down but you don't build power same way you did a second before, the stock system tends to err on the safe side not the preformance side. Plus if GM put these sensors in LT4 corvettes with factory warrantys I'm sure it not that over the top. I believe the Knock sensor 3rdgenZ was talking about still detects pre-ignition however it waits for more than one little event before reporting it to the ESC module. That is my basic understanding of the sensor, 3rdgenZ... you may want to correct if needed.

anthony64ss, Thanks for checking though.

TPI-Formula350-

Is anyone running the LT4 knock sensor? I'm getting a few knock counts and my AF is 12.5 at WOT and only running 29* total timing. I suspect my knock sensor is picking up a false knock from an exhaust rattle which I plan to correct this weekend. If correcting the exhaust rattles dosen't clear the issue I was looking into getting the LT4 knock sensor. I have heard it is a little less sensitive because the LT4 vettes ran roller rockers. I'm way past roller rockers so I'm thinking that knock sensor would work better then the stock L98 one.