Timing is still a mystery to me

here is my question... i have a ecotec, and hptuners...

hypothetically speaking would changing the timing tables in Engine > Spark Control > HO (PE) and LO (PE) to all zeros be completely safe? or would it be stupid?

I have no idea what the outcome would be and im not going to try it either, i was just wondering...

The way I understand it you can see gains from advancing timing until you see knock and then you pull timing in those spots to get rid of the knock.... but .... what if the table was zero'ed out? would the engine blow? or would it just be a lot slower and safer to drive that way?

Any help is appreciated...



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|

Ok first your not always going to see imcreases by just increasing timing until you get knock. The only real way to see if increasing timing is adding power is to be on a dyno. YOu can increase timing and knock have knock and lose power. I know some people are going to jump in and say I added 4 degrees and the car pulled harder, well show me dyno proof it made more power. I'm not saying adding timing will not give power, just you will not know how much timing gives you increase. Might only need 2 degrees's and everything past that kills your power.



FU Tuning

any info on my question?



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|

will the car run? prolly.. engines are more forgiving than most people give them credit for. will it help remove all knock? maybe, maybe not. if your not firing the plug till too late you can knock and fire too much on the downstroke and damage stuff just as advancing can fire too much on the upstroke and damage stuff. me personnally, I'd trust GM until I get my car on the dyno. going all 0's could in fact really damage parts since timing is advanced a decent bit on our cars. I'd say a stupid idea. the software you have has the potential to REALLY mess up your motor. which is good and bad. not a toy or something to take lightly though. there is not a built-in dummy warning *Are you sure you want to empty you're Trash bin?* lol nope, just blammo

listen to john, if you datalogged and found knock at certian tps/rpm points then try to add some fuel or retard timing a LITTLE till it goes away. play with both. doing so on a dyno will help you rid yourself of knock and keep the most performance.



Sven you totally quarterloafed your computer..

mm... if you zero'd the table that would be bad. Ur car would never try to ignite before the piston his tdc (at hi rpm). Whats weird is that at idle, theres the most advance in timing...if my memory serves me correct. More then at wot . weird eh. The safest timing is stock and leave ur lo table stock too.

Nateh



Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft

I'm no tuning expert, when it comes to computer controlled motors. I have found a good read, that should help:Flash It-How to Program an OBD-II Powertrain Control Module from Chevy Hi Performance Magazine. It's a good read on how to tune your motor safely. Will it make the most power? No, but it should help. Nothing beats a good dyno tune. Will it make you a tuning expert, definitely not, but it's a step in the right direction.

Zeroing out you timing will kill performance, emmisions, fuel economy, the car will run like c&@% and you could damage the motor and/or emissions equipment, so don't do it.

thanks guys!! good info



|Forged 8.9:1 Wiseco Pistons|Forged Eagle Rods|HPTuners|60trim|Tial Wastegate|
|Precision Intercooler|2.5" Exhaust|2.5" Charge Pipes|630CC Mototron Injectors|
|Stock: Fuel Pump, Transmission, Manifold, TB, Head, Head Gasket, Ignition, Suspension...|

too bad the spark advance part wasnt clear



1989 Turbo Trans Am #82, 2007 Cobalt SS G85

Ok, I've never heard of an engine getting messed up because of retarded timing. It will run like crap tho. My first car ran 2 years with the distributor and cams one timing belt notch retarded because the mechanic that replaced it the first time was an idiot. No engine trouble at all ran the @!#$ out of it(kinda had to the car was slow but I read it was supposed to be). You'll just lose power and get @!#$ty mileage. The optimal engine will burn everything all at once at TDC creating HUGE amounts of pressure. That happens only in diesels right now and that's one of the reasons they get 57% thermal efficency instead of the 33% max a direct high pressure gasoline injection engine gets(for the record compression plays a big part in that too). If the ignition is too late it will waste alot of power out of the exhaust port at any throttle or load and the gasoline should be completely burnt before the piston is a quarter down on the power stroke and if the timing is too late it won't be. On the other side audible knocking(detonation) is a huge waste of power and can be extremely damaging. Here is an interesting read. Knock article

So your basicly riding the edge of too much timing to not enough. Now with extensive dyno testing you can tell where an engine has optimum timing. I read an article where a 318 was tested over and over again. on timing with different octane levels and it got to a point where advancing the timing more regardless of octane level didn't yeild any more power and in some cases reduced power. but overall it was obvious that once optimal timing is found there is only about half a horsepower increase with an octane increase to premium from regular. Not much power to be had once optimal timing is found. But that timing setting is going to change with a compression change or cam change.


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'96 Cavalier Good ol' Pushrod 2.2
-24X,000 miles on factory build
-Some oil loss between changes, me thinks it be rings.