I have a very slightly modified engine (check the sig), and since adjusting the timing is free, I would like to know what is a good setting to adjust it to? I always run 93 octane, but I'm not looking to adjust it to the point of extreme.....what ever that is?

Oh yeah....what's stock? and why would they set it like that when the only thing from adjusting your timing is good results w/o taking a hit in gas milage?

 

0* is stock and that's because thats where the least emmisions come out.

Every engine seems to like different timing. I've found 8* to work well with my combination.

 

im running 12

 

i got about 6* right now seems to run fine

 

but advancing it higher than the stock zero will always make it perform better? should i start out like at 5 or 6 and see what happens.

 

we just sat there and messed with it till it sounded good and agresive at idle without wanting to die on us. then wed take it out for a drive and see how she was. when i was at 6,, lack of power and the car died at stops, 8 the same thing, 12 was perfect!! awsome power, no knocks or pings. just start at 6 and work your way up. i think on the stock motors our not supposed to go past...what.......8??? but i have heard that 12 is a good spot for most with stock engines. good luck, tell us what happens

 

Also something to keep in mind, if you have aluminum heads or are running a cooler thermostat, you can usually get away with a little more timing without detonation.

 

Well I'm running a 180* t-stat and a jet fan switch....so what does that allow me? I also always use 93 octane....

Is it possible to advance it too much?? If so, what would be the signs of that?...knocking and pinging I suppose?

...and finally, why would a car die at 6* as opposed to 0*....but be fine at 8*? I'm a little confused as to why this would happen.

 

the only answer i can think of is, that it was a new engine that i was swaping into the car. so im guessing the total timing was off and causeing it to die. im running a 195 temp thermo and 87 octane.what is your compresion? if you have 8.5 compression like i do,, y waste your money on 93?....i havent had one knock or ping using 87 and the motor now has over 1000 miles on it.

 

dont get mad if im wrong but im pretty sure the f body lo3 has 9.4:1 compression...still doesnt need 93 tho i usually run 89 soon as i get a timing light im gonna play with my timing some

 

I believe its 9.1;1, not 9.4 - pretty close, doubt there is much difference in anything. I *think* GM "recommends" 87 - but I found 89 works the best (if you include both performace AND price!)

 

seems to me like 87 run kinda iffy i dont know 89 seems to run good and 93-94 no better so i dont waste my money

 

Stock base timing for 305 is 0 degrees,350 is 5 degrees BTDC.
My 350 likes 16 degrees of base timing, but can be difficult to start and needs octane booster added to our weak California 91 Unleaded.
If you advance it too much, the computer will hear the knock and retard the timing accordingly, so don't go too far.
-Rich-

 

ok thanks, ill adjust it to 6* and see if i see an improvement. ill probably just leave it at 8 if there is an improvement

 

I'm running 12

 

what'r you 350 TBI guys running for timing? I'm at zero right now and am really looking to raise it some...but how far? Is it any different than a 305?

TP

 

I also have an L05 - I am very interested in feeling the gains of adding some base timing, but first I need to buy an inductive timing light...if I run Mobil 89 all the time, how far can I expect to advance it? 2-4 degrees BTDC?

 

alot of you guys are running way way too much timing. I made the same mistake back in my near stock days.

on an L03 i dont see running past 8 as even being possible without detonatin.. the stock L03 chip provides about 30 degrees (give or take a degree depending) of total advance with the base timing at 0
theres no way a 9.5:1 305 would need any more than 35 or so. I start at 4 degrees and maybe move to 6 base timing but definately not more than 8

it might run better at part throttle though and that is what will fool people into thinking its better all around


this and excessive fuel pressure I think are the most common tuning mistakes tbi'ers make

 

With the mods you see in my sig, including the Jet Stage II chip, I have my base timing set at 0*.

I have a SunPro timing gun with a dial on the back so I can line up the timing marks on the damper and the pointer.

At first I set the base timing to 6* BTDC thinking that it would add more acceleration. It didn't. Well not enough IMO to justify the added cost of the 92 octane here in IL. Nor the new tires. So I set it back to 0*. The SOTP meter felt no difference.

The main reason is this, or at least I think it is;

As you know, the ECM uses a lot of info from all the sensors to get a good "overall" running engine. So I can't say that what I did was 100% accurate. But here's what I did.

I set the base timing to 0*, plugged the EST thingy back together and checked timing again. It showed 22* BTDC at idle. I then tried it with the base timing set at 6* BTDC, plugged the EST back together, and still got 22* BTDC at idle. Some how the ECM can compensate for that. Again I point out that all the sensors working together is probably what caused that.

Well, having experience with vacuum advance distrbutors w/mech advance weights and springs and using a variety of those parts to set the timing curve, I figured I could try writing down the timing curve before and after I changed the base timing from 0* to 6*.

Since then, I don't have the charts that I made. I lost them. But I can tell you that sitting in Neutral, with a friend holding the RPM to 4000, both base settings gave a total timing of 44* BTDC.

The engine will probably never see that much under a load just because the MAP would send a different signal to the ECM, as well as the VSS, the Knock Sensor, the O2 sensor, TPS, IAT, etc. But I can tell you that the engine's timing does have the potential to advance that far.

I just wanted to shed some light on what I've experimented with, and what results I got. I think it should only help to advance the base timing as long as the knock sensor isn't working overtime. But I feel that it won't make that much difference. I guess a dragstrip is the only place to tell. And don't worry, I'll be doing that also.

I can't give you a side by side comparison of the stock chip to the Jet Stage II chip, but I can tell you that since the engine was under no load, and nowhere near WOT, that I probably would get very little, if any diff. Mainly due to the Jet chip only altering the timing curve and total timing under WOT.

AJ

 

advancing the timing can be done by the old school black art method is watchign for engien vibration and listening to theexhaust or by using a tim ing gun adn a laptop.
the basics are this, if you advance your timing adn the car develops a little lope or if it starts to sound more aggressive then you have reached the land of knco at idle. the only thing properly set timing will do is raise the idle rpm slightly until the ecm compensates it back down. if thereis any rock or knock(hey, that rhymes) then are have gone a little too far.
when you use a laptop to set it with win aldl you can see the knock counts and base how far ahead you can set the timing from that. it is more accurate and wil be safer to your engine, your emissions, and you r fuel mileage inm the long run.
the reson the factory set timing to zero is because they based the timing off the computer tuning, the est gives the car 6-8 degrees at idles beyond where you set the base timing to. so if anyone out there is seeing 12degrees when you put a timing light on it you really have 4-6 degrees of actual base timing in the car.
the only detriment of advanced timing is that if you sit at idle or in slow moving traffic for too long the engien will sort of load up a little and if you nail thegas just getting out of the traffic the throttle response will be a touch off, but that one throttle snap will clean the plugs and all will be back to normal.

later
tim

 

I'm not sure I understand all the techincal mumbo-jumbo? Maybe I should quit college and go back to technical school before I adjust the timing