BTW - I also leaned it out to 12's AF and got real knock, you know just to verify the sensors are working.

 

Any of those on straight 93 no meth no E?

 

So just now between my post and yours you went out and made a few dozen pulls to make a point? I didn’t say 10-10.5 would or wouldn’t hurt anything I said I see no reason to do it. 11-11.5 works just fine and on e85 even leaner is fine on “some” setups.

 

Yes, up to 13-15PSI on an LS that's about all I push on straight pump and I don't feel much more boost is terribly safe on straight pump unless its something like a 4 cyl with a little turbo then I've run 30PSI.

 

No its raining here today, I was out messing with my car last night anyways so I threw tune in both directions on my little test track. I didn't see any knock at 10.5 or 10.25 so I kept going down into 9's just to see if it even would. There's really no reason to me to run leaner then 11.5:1 on a boosted setup, especially a turbo setup as boost control isn't always as consistent as a belt. When superchargers have an issue boost normally goes down, but when turbos have an issue boost often goes up. While you may have a boost cut in place its generally not exactly where your tune is and its a few PSI above, much like when weather is colder and you make a little more boost I'd rather be safe there then have it lean out anymore then needed.

 

thats about usually where I stop too, except for 1 time we went to 19 psi.

 

Ya depends on power level more then boost really, some power adders don't gain much hp/lb with more boost. Here's looking at you LSA's, or to make it fair small turbine single turbo setups.

 

I tune mostly Dodge Hemis on the dyno. Never seen knock from too rich. Talking pump gas here. We get 92.

The interesting thing about this discussion is the simple fact that you aren’t logging actual knock. You are seeing the resultant retard the ecu applies to the timing after is sees the knock. Remember the knock has already happened. Retard is the result. And the retardant of course is the result of more than a few parameters in the tune you can change.

Back to the Hemis. In this setup, we can view the actual knock sensor volts in real time. Pretty interesting. You see the spike, then see the retard.

We run them 11:1 on pump fuel when boosted. No more than 7-8 psi if stock bottom end. The mighty Hemis are fragile! Ha!

We pretty much gave up on pump ****. Waste of time if serious about going fast with any sort of reliability

Back to the original story. Two bent rod bolts and the rod cap in the pan? I’m wondering if that rod got missed when torquing?

Ron

 

No im almost certain i torqued tht rod. I always double check all of them to be safe.

Im been thinkin on this lately. I think the block had a crack in tht cylinder, tht eventually busted and basicly bent/broke the rod etc.

Truck was having some issues were if i made 2 pulls kinda back to back it would get pretty hot. It would eventually cool right off when cruising. Never got hot at idle, in traffic etc. Just after 2 back to back hits.

This is why i think it might have had a hair line crack tht could have busted! Thoughts?

U can also see where the rod dug into the crank journal. This is what broke the cap/rod bolts. It took a hell of a hit. And for the rod to be twisted and wrinkled like it was, it does seem possible.