Solid Motor mounts setting off KR

[NASABlue]

I'm getting some knock retard, would solid motor mounts set this off?

I probably have 11.2 :1 dynamic compression.

I have read the other recent post where 97-98 knock sensors should be replaced, but I don't understand why.

I can also soften up the sensativity through certian RPMS.

Thanks for any insight!

[mr.prick]

The 97-98 knock sensors are inferior to the later versions.
I have solid mounts and get occasional KR.
My spark plugs never show any signs of damage so I assume the KR is false.

[NASABlue]

should I update the knock sensors to 99+ and will this cause any other issues? (are they plug and play compatible?)

I looked at the part #'s and they are distinctly different. Wether or not it's just application, I'm not sure but the local chevy dealership won't even quote a price without the last 8 digits of my vin.

Any help from you experienced guys would help.

[joecar]

You also need the wiring/connectors... just tell your local Chev. dealer you want knock sensors and wiring/connectors for your 97 Corvette... their parts computer system should show that there is an updated part available... just tell them your year/make/model, they can do it without a vin.

[NASABlue]

Did this stuff guys, still have KR

Changed to a FAST manifold, still have KR

Changed the motor mounts, still have KR

Changed the PCV system to include a breather on the fresh air side in case I was pulling oil into the manifold and included 2 catch cans on the vacuum side of the system.

Still Idles bad and has terrible KR over 3500 to 4K rpm and on up. THere has to be some big piece of the tuning equation I'm missing.

[GAMEOVER]

Post up your tune...

[joecar]

Also post log files.

You may have to get an electronic stethoscope and listen to see if it is real knock.

With that much DCR, what gas do you use...? What is your SCR...?

The reason there is replacement knock sensors and subharness is that GM found out [after the fact] that the original ones were faulty in some manner prior to 1999 or 2000 (I could not get any specifics).

[NASABlue]

Thanks for the insight on the Knock Sensor replacement. I never begrudge replacing parts for updated ones.


I milled .021 off the heads and the head gaskets are .041 Felpro because I couldn't sleep with the Cometics. I was just never sure they were sealed because of the way it was running. At first they were leaking oil&coolant, then it appeared I tightened them up before I saw evidence of oil again.

Anyway the total chamber size should be 60cc, maybe a little more with the piston flycut on the intake valve. I'm using 93 octane. I don't know the exact Static or DCR but did add some octane booster that said it would raise the fuel value by 3 points.

Over on the corvette forum, the torch helped me figure DCR to be ~11.15:1, but I suspect it might be a little higher. I think we came up with an 8.3 or 8.4 number for SCR.

It's been so long since I started this, I forget what reducing the chamber by 1cc does to the compression. Edlebrock indicates removing .007 from the head reduces the chamber size by 1 cc. I think the heads start with a 10.5 to 1 compression at 65cc, but could not verify this from their spec sheet.

[NASABlue]

I will post up tunes and logs when I get to that computer in a few hours.

I definately searched and read up on the posts on softening up the knock sensors and timing. There's a lot of what appears to be overlaping data that confuses me. I don't understand when Power enrichment takes control or how to adjust for that vs the rest of the tables, but I'll hold off on what I don;t understand (we could be here for a while) untill I post up the logs and tune files.

thanks

[mr.prick]

You may find that KR gets lower as cell count increases, so make sure you hit those cells more than once or twice before subtracting KR from the spark table(s)
Try reducing {B6203} 30%, increase {B6702} 50% & increase {B6245} 5%.