C5kid

iTrader: (12)

Ok, over the winter I built a forged 347. Speed Inc SC3 blower cam, 10-11# of boost. Fuel pressure holds steady @ 58psi and injectors only go up to 85% duty cycle.

Diamond blower pistons -8.6cc
243 heads
GM MLS head gaskets

When i do the math

Bore 3.905
Stroke 3.622
Head gasket dia 3.92
gasket thickness .051
piston out the hole .01
head cc 64.43

I get a compression ratio of 9.75

SO, I am been chasing down this knock issue for a while now. I thought I had it tracked down.

If I get on it sometimes it will run BEAUTIFUL, the next time it will pull a huge amount of timing 4-5* and you can def. feel it. BUT there is no audible knock.

I have tried good gas and it will still act goofy.

There is only 12* timing @ WOT throttle, plugs are TR6's gapped to .032.

edcmat-l1

iTrader: (10)

Data logs..........

stevieturbo

And how are you listening for knock ?

Unless you are using a stethoscope type device, it is impossible to make such a statement.

white01ss

iTrader: (37)

What's your AFR and IAT at the point of knock? This summer has been crazy hot all across the country. I've had to subtract a little timing based on rush hour IATs in the 130s. The stock IAT spark reduction isn't aggressive enough when boost is introduced into the mix.

C5kid

iTrader: (12)

IAT's are around 80*, and AFR is right on 11.5

I am goin to upload the tune and two logs.

The 7-13-10 log is where the car felt GREAT, added 1* of timing w/ the VCM RTT and she was ok. Just fast foward to the 1:00 min mark and you can see the quick pull I did.

The 7-16-10-6 is the exact same tune. w/o the 1* of timing and she is knocking like a ****.

Also attached is my tune.

C5kid

iTrader: (12)

Ok here are two back to back pulls from tonight.

The first one the car ran great, no knock. Was still on teh highway and did another pull and she freaken acted up.

Here is the tune and the logs.

-3 no knock
-4 2* of knock.