Just some interesting observations last night during a tuning session.

I've recently hooked up my MSD knock alert to my block and it's really opened my eyes to where I need to work hard to tune. As many know here, I have the typical "stage 3" setup with 8 injectors (440cc's being my secondaries).

The MSD Knock Alert allows me to hook up this box with a metered display very similar to a flashing light a/f meter to an extra stock knock sensor screwed into the back of the block. Anyways, as I drove the car, I noticed right away there was some knock. First off, I saw that I never had any knock up to 10 psi. Regardless of rpm or psi (less than 10), if I were less than 10 psi, there wasn't ANY knock.

However, once I ventured above 10 psi, I did notice my meter start to pick up things. Right at 10 psi, and 4000 rpms, almost every time the very first light of the meter would light up. Then it would go away higher in the rpm band. However, the meter would REALLY light up and go all the way to red just for a second on a hard shift at 15 psi. It wouldn't go that high at all though, except for above 15 psi.

After reading those, I messed with my settings on the EFI a ton. By going into the matrix and richening up the above 4000 rpm spots some, I was able to totally eliminate the +10psi, 4000 rpm one bar light up. I also richened up as much as possible the +15psi level. I was able to eliminate about all of the knocking there. However, I can still get it to knock some, if I do a quick downshift into 15 psi. It's not the gradual build to 15 psi that causes any knock. I still need to work with this to see if I can eliminate that knock altogether.

Lesson to be learned here: You may be getting knock and not even know it. My egt's have always been conservatively low. I want to hook in my datalogger next and see if timing is being pulled at all by the stock ecu when it detects this knock. BTW, I still have another brand's knock meter for sale.

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Jason ESi-T

04' BMW 325Ci
91' Nissan 240SX
98' Eagle Talon ESi (sold)