Should it be clattering at this low boost?
 

Quick question.....well I'll try to make it quick lol. Have i reached the limit of boost? I'll give you guys the quick rundown.
ls1 gto of course
243 heads (more compression) ported and the chambers were smoothed and polished
btr NA cam 227/234 113 lobe sep. (Was thinking the overlap would bleed off cyl pressure)
pump 93 octane
12 degrees timing straight across the chart. ive reduced it after 5000 since
**i think I have tr55 plugs** I'll check when i get home. I hope i do because it may help to go colder
only happens at 9.5 psi. 8 psi is fine
Things of notable mention: the down pipe may be a little restrictive. its 3" but i had to flatten it to about 2" wide so i know the flow is cut down some, very near future plans are building a new one using 3.5" oval tube from cx racing...pipe is on the way. Next is my afr starts go go rich (11.5-11.2) right round the time I get clatter. I'm st 5600rpm (could that be my tq peak?) and 9.5-9.8 lbs of boost in third gear wot when it happens. I see it try to pull timing but i had limited that when it was NA (i fixed it last night and allow timing to be pulled). I have not pulled the plugs yet. I'm gonna put a fresh set in (colder) and get a few extras and make a hit and look at them.

so whats your thoughts? 9 psi the limit? I retuned my buddy's supercharged 4.8 extra cab silverado. He was running 12-13psi and had timing higher than me altho the 180f IAT's were pulling timing to 9 degrees. I always thought that timing that low was dangerous but his lived quite a long time. its knocking a little now because of no oil pressure (whoever did his cam swap replaced the oil pump and it lost oil pressure from what he originally had)

uh what does clattering mean?

oh thats not good. yeah 5's are way too hot. we get away wth 6's on 10 psi, 11* and pump gas and water/meth but a bad tank of gas will ruin your day

7's are the way to go. pull back idle timing to 18* to keep some heat in the head and they idle fine.


whats up with your knock sensors? you pull a fresh plug to see whats up yet?

You're crazy for runing a tr55....put a 7 in it.

9 PSI the limit of what? You're about 10 PSI short of what an 04 LS1 can easily handle.
Swap plug out for BR7EF. I usually don't even gap them and toss them in straight out of the box. Part stores might use part number 3346. I usually buy them 40 at a time LOL.
After that, water/meth is probably on your to-do list. You can just run blue -20* washer fluid in it.
I solely attribute washer fluid to saving my stock 5.3 from detonating and scattering when my wastegate failed and I stayed in it at 40 pounds of boost on pump gas.

As for timing, you should reduce timing at peak torque, and then increase timing up top when torque starts to fall off.

Is there any way for you to log knock? Why guess?

What kind of valve springs?

i watched the video and didn't hear any obvious knock, just compressor chop from the bov opening

thats not to say it's aint knocking though. by the time you can hear it in the car....shit is done for

Are you sure about this??? I've always thought it was the opposite ie. increase idle timing to avoid cold plug fouling.

IME retarding the timing makes them idle a little hotter. my old man explained it to me as such:

when you retard the timing at idle more of the fuel mix is converted into heat instead of work.

I had trouble when I first switched to 7's and I pulled my idle timing back until it smoothed out.
I also noticed that I could get away with almost 16:1 afr when it was warmed up and it idled really nice.
That's on the pump piss 92 gasoline we have here on the west coast

Yup. I think I have my 230/230/114 at 18 degrees and have idled in the 16's smoothly as well with the BR7EF that Joe mentions. Good ol 3346.