Still knocking!!!!

[SRT8_T]

so i backed off the timing a bit and its still knocking!!!! im frustrated now... so if im stopped and run through the gears the knock is minimal 1.5 to 3 the most. but sometimes while running through the gears the knock jumps to 6 or 7. also when im holding a gear anywhere from 3.5k to 5k rpm and floor it you can hear the knock and it reads that it jumps to 6 to 7. i mean am i gonna have to shell out another 400 dollars for a dyno tune?? what should i try now. do guys have a california map?? we have shitty gas over here please help. also how bad is this on my motor?

[Quick]

It's not extremely bad on your motor unless that's all you do all the time. It's not real good on your motor either. The PCM reacts to knock up to pulling about 9* of timing. So you get the initial event (more or less a single knock) and the sensors pick that up. Depending on how severe it is they send a voltage proportional to the knock they heard to the PCM. The PCM sees how far over the threshold the voltage is and decides how many degrees to retard the timing to eliminate it. The PCM is pretty good at this and generally pulls enough timing to completely eliminate the knock. Then the PCM keeps reducing the amount of timing retard and checking the knock sensor signal to see if it continues to go down and stay under the threshold. So you do get that first single knock before the PCM reacts by pulling timing. So you're probably not going to do any damage but it's not desireable. If it goes over 9* (the pcm only pulls up to 9* (or something like that) so you won't see any higher value but it's going to knock and that *would* do damage.

So you've probably got bad/not so good gas AND you've probably got oil in the manifold. How about you try to drive conservative until you get a catch can on there and give it a week or so for whatever oil there may be laying on the bottom of the manifold to dry up. If you just can't keep your foot out of it how about putting the stock tune back on there in the mean time. Matter of fact, you should try putting the stock tune on there anyway and log for knock retard just to see what that's like. I'd expect it to be about the same or maybe even worse. The tunes desensitize your knock sensors a little bit.

You may not get anywhere until you get a catch can on there and eliminate the oil. It's not 100% gauranteed that's the problem but a whole lot of people with the 6.1s have seen a very significant improvement with a catch can if not eliminating the problem altogether. I sort of get the impression that you've discounting that but the great majority of SRT8's that I know of are running catch cans and most have seen a significant improvement when tuning/running tunes.

[SRT8_T]

ive never noticed any knocking when the car was stock but sounds like a plan i'll put the stock tune back in and wait for my catch can its on order and should be here anytime now. can i still run my fan lower settings with the stock tune? thanks quick

[johan]

Yeah i was gonna say, if you get knock that is that inconsistent i would say you have some oil in your intake.
When you have real knock due to running lean, too much timing, poor quality fuel etc etc the knock is pretty consistent with the highest probability of knock at peak torque.
I would put it back to stock and get the catch can and put some miles on it with the catch can to clean things out then put the tune back and log again.

[SRT8_T]

would you recommend i pull the the manifold and clean it out?

[Mike_Levy]

Pull the mani, clean out the oil, and smooth the ridges caused by the molding process. When you pull the bottom cover off to clean it you'll see them. Theres one in each runner where the mold halves come together.

[Quick]

Sure, leave the fans. There is a "Modify stock tune" option right? raise shift points, change the fans, no problem.

Not really necessary to pull the manifold. The oil that's in there will evaporate/get sucked into the cylinders (like it is now) and it will dry up. It's not a huge job to remove the manifold but it's not small either. fuel rails, you always risk the gasket, etc. etc.

[MagnumSRT8]

I ended up having to add quite a bit of fuel to get my knocking down to a minimum. If i remember right im running about +8 low +14 mid and high range for fuel. I tried adding less fuel and dropping timing a few degrees but got the best performance with just adding fuel. Ran 12.7@110mph at the track with a airhammer 180 thermostat and i cut the muffler and resonators out and welded in some zoomers mufflers.