I noticed in the new to tbi forum that it said about timing, " The factory setting says to but it at 0* but most stock LO3’s like a bit more. This is a trial and error procedure and you will find that most LO3’s prefer anywhere from 4* to 8* advanced". I was wondering if i tune my engine up to lets say 4* then is there a possibility that my engine could blow...or is that just me making a mountain out of a molehill?

 

No.......your knock sensor will hear the predetonation and the ECM should back the timing off.

 

you will be fine i'd up it about as high as you can then back it off accordingly if you hear any knock. Just my opinion though.

i had a tired old l03 that ran terrible with any less than 10* timing. I ran 12* on mine.

mine would bog and ping with 0* since it was so old and worn. It was the biggest mistake i ever made setting it back to the factory 0* lol......

my current tpi 305 on the other hand thats a fresh engine enjoys 8* and it's factory 6*.

kind of a trial and error most tell you they wouldn't go more than 8* but, to those people i would have to say that going anything less was terrible in mine so to each his own.

 

I keep hearing everyone talk about knock....what exactly is it? how do i know its doing it? sorry i know some stuff about engines but not that

 

well it's pretty much just like it sounds, if you hear a knock or a ping you have went to far.

that knock or ping would be detonation or preignition. Both of which definitions are quite like their names, so use your imagination, if u still have trouble say so and i'll post a good explanation.

You want the spark to ignite your air fuel mixture right before the piston reaches top dead center. Therefore instead of it igniting at top dead center and hammering down against the rod bearings, the 10* angle the piston is at helps the piston to be forced down much easier.

the higher an engine revs the sooner you need to bring spark advance on (to a point), most engines tend to run best if the spark hits 10*btdc, basically this makes perfect sense if you think about it. sbc engines in general tend to like 32-36* overall advance all in by about 3k-3.5k rpms. Anything higher and the advance does not help much due to how far the piston is down in the cylinder. Your mechanical/centrifugal advance is controlled by the computer on efi cars, so all you have to worry about on yours is base timing.

now the above is a generalization and is not 100% true of all engines of course. The basic understanding is that the best angle to acheive is at 12* btdc if memory serves me correctly but, due to the very small ammount of time for the spark to propagate + taking engine rpm in to consideration, igniting the mixture closer to 10*btdc works better.

the above numbers are not set in stone, cam profiles and head designs have a huge affect on the above along with engine load, timing chain and sprocket wear, dizzy gear wear so on, basically its just a generalization to give an easy understanding of the subject at hand.