I have a question, and it may sound dumb, but when we get detonation in our cars what does it sound like. does it sound like pinging you would hear in a v-8, like a deisel engine? I get this awful sound now and then that sounds like a real loud rattling coming from somewhere in the engine bay. almost like the sound you would hear if you rolled alot of loose ball bearings down a corrugated sheet of steel.(the best i could explain it) it only happens when i go quickly into boost, lets say if i step on the gas 1/2 way down and the boost rises gradually it doesen't happen, but if i step 1/2 way down and then when i am in boost i decide to push the gas 3/4 the way down i will hear it. It was worse when i had the 10.5:1 pistons. i would hear it every time i went into boost. but now since i got the 8.8:1 pistons it seems to be less. and i was playing with the programmable dis 2 and retarded timing and after that it appeared to be less. at WOT my ecu is showing almost 30 degrees of timing advance. I am going to try to pull out alot of timing and see if it is still there. This sound ONLY happens when i go into boost. It NEVER happens when i am in vacuum.
Thanks for the help
James

You know what, i get the same kind of sound, just as you described..almost like a metalic spitting sound or something..and rattling..its wierd, and only does it just like yours does. I've always thought detonation was a pinging type sound too. The only thing i can come up with is its either the wastegate, or oil spitting out into my catchcan...i dont know..anyone have a clue?

I've heard it sounds like this. Take a wrench and bang it in your garage floor (cement).

for some reason it seems like it comes from near the passenger foot area of the engine. you know what it may be the wastegate, i never thought of that. i have an AVCR and that cycles the wastegate open and close top control boost. I am going to disable the avcr and see what happens.
thanks
james

>what does it sound like? I get this awful sound almost like the
>sound you would hear if you rolled alot of loose ball bearings
>down a corrugated sheet of steel.

Thats detonation! I got that ALL the time with my old HRC fpr when it was adjusted wrong. It pissed me and RRE off to no end. All your datalog & guage parameters will look fine, then BRAATTABRAAAATBRAA. My best explanation is that my #4 cylinder was running lean. Fuel pressure was fine, but FLOW (actual lph) was waaaay low.

I'm gonna bust out a big trash can & measuring cup and see if I can prove this scientifically somehow.

Easy way (for James) to confirm detonation sound: There's this Left-hand exit at the end of the 105 fwy that, instead of forking out to the 605N/S, just goes into the carpool lane and dumps you out on Studebaker. Boost it up this little incline as soon as you exit and GUARANTEED detonation. You can even get your choice of 1, 2, or 3 cylinders detonating if you practice :o

>>what does it sound like? I get this awful sound almost like the
>>sound you would hear if you rolled alot of loose ball bearings
>>down a corrugated sheet of steel.
>
>Thats detonation! I got that ALL the time with my old HRC
>fpr when it was adjusted wrong. It pissed me and RRE off to
>no end. All your datalog & guage parameters will look fine,
>then BRAATTABRAAAATBRAA. My best explanation is that my #4
>cylinder was running lean. Fuel pressure was fine, but FLOW
>(actual lph) was waaaay low.
>
>I'm gonna bust out a big trash can & measuring cup and see
>if I can prove this scientifically somehow.
>
>Easy way (for James) to confirm detonation sound: There's
>this Left-hand exit at the end of the 105 fwy that, instead
>of forking out to the 605N/S, just goes into the carpool
>lane and dumps you out on Studebaker. Boost it up this
>little incline as soon as you exit and GUARANTEED
>detonation. You can even get your choice of 1, 2, or 3
>cylinders detonating if you practice :o


Holy crap! Loose ball bearings is what mine has sounded like occasionally..never knew it sounded like that..haha thats not good :o
I too have the proper fuel pressures, and got that sound, but maybe its just not enough fuel flow somehow..i dont know how it could do that, because i'm only running 7 psi, as others have run 10 psi on stock injectors before...hmmm..i just might get the 315cc injects sooner than i thought..So thedawg, what did you do to remedy the problem? larger injectors, differnent FPR??

thanks Dan,
i will try that tonight and see what happens, you know what though, i disabled the avcr and ran the wastegate by itself and the noise almost completely went away. the funny thing is i got 440's HRC inline pump, Walbro intank pump, -6AN fuel lines throughout, so i don't think my fuel supply is the issue, probably just tuning. I am going to retard the fuck out of my car so it is really super retarded and see what happens.
Dan, hows the engine coming together? sorry I couldn't be of any help, too much unexpected shit going on. but you can always gimme a call if you got questions and i'll be glad to offer all i know.
Thanks
James