View Full Version : Advanced timing on 5.7 tbi
03-03-2011, 07:44 PM
Hey guys I have a 5.7 tbi with a mild rv cam. I haven't felt like it was running right so I advanced the timing a little bit. It's running much better but I'm not sure how much I can advance it without getting premature detonation etc. Any imput would be helpful.
1988 GMC 355
03-03-2011, 08:01 PM
I have mine at 6* with no ill effects and a few guys on here run at much as 12* advanced with a cam and increased fuel psi
03-03-2011, 08:06 PM
Well it's a daily driver so I definately want it to be safe! And I run 89 octane in it at least. I like running premium but gas is sooooo high!!!!
1988 GMC 355
03-03-2011, 08:16 PM
I hear ya on the gas deal!!!
But where is the timing now?
are you running higher fuel psi?
id say increase it at 2* intervals until you think its going to get as good as it can get. prob 8-10 would be good and safe for sure
03-08-2011, 04:40 PM
Ya we have added a bunch of timing & fuel to crappy .bins, but those are an exception not the rule.
As always I must insist that just dialing in more advance via distributor position without data interface is a is a BAD idea.
As a rule you run into the Knock Sensor between 4 & 6* advanced from factory settings.
I hope your KS functions correctly or you risk major engine damage.
TBI tuning is a matter far greater than boosting fuel pressure & timing.
03-10-2011, 06:51 AM
Here is a screen shot of my timing table. My timing is set to ZERO. It's AGGRESSIVE! My 93 K1500 - 9:1 / roller cam / 1.6 rocker arms / 454 TBI / Shorty Headers / 3" Single Exhaust / 5.7 liter runs fine with 89 octane using a 180 degree thermostat.
HOLY CRAP that is aggressive, indeed. You run that on stock tbi heads?
Where are you in WA? Do you do any mountain driving? That's the true test of SA; I've found pinging tends to happen around 90map going up long steep hills...
I just got my SA to the point where i said "wow! there's my missing 50hp," but damn.. that's a lot of SA. I've got a vortec-tbi, and I'm now thinking I may bump mine a bit further and see what happens. :D
03-12-2011, 07:59 PM
Yes, I use "193" TBI heads. I live close to Mt Saint Helen's, so I routinely see about 6,000 feet (or more) above sea level. The ambient air temperatures were I live rarely gets above 90 degrees F, and the humidity is usually about 70+ % most of the year! I guess the mild weather is why there is huge forest near by me!
03-15-2011, 05:23 PM
Mine is Around 6. When i up'd it to around 12 it started pinging.
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