I have got a stage 1 chip and was wondering if i should advance my timing also. Ive heard your not supposed to advance it any with a stage 2 but should i do it?

 

I wouldn't go beyond 4* advanced mechanically. You'll knock at WOT. Do yourself a favor, put your stock chip in your car (with premium gas) have a friend drive it and blast it a few times. Don't tell him/ whats going on and the next day, have him/her drive it again WITH the chip installed (do not let them know what you did) and see if they notice anything. Just to get rid of the placebo effect.

Or better yet, do a dyno or 1/4 mile run. Not dissing you or anything, stage 1 chips (even stage 2 off the shelfs) are worthless, in my opinion.

 

i put my car on a dyno last thursday night and tried different timing settings. it's amazing how sensitive to timing changes l03s are.

at 0 degrees advance, the car did 149 hp and 239 lbs ft torque.

at 6 degrees advance (87 octane and no knocking) the car did 164 hp and 254 lbs ft torque.

that's a difference of 15 hp and 15 lbs ft torque!

the distributor advances 25 degrees. the chip won't change total advance, all it can do is change the advance curve. small blocks traditionally like 33 to 34 degrees of total advance. that would seem to call for 7 to 8 degrees of initial advance, but it definitely made best power at 6 degrees initial.

 

The small cap HEI distributor is capable of 42° of advance and 3.8° of retard. This is from the base timing point. Other then those limits the ECM has total control over all aspects of the timing.

RBob.

 

wrong, you can change the initial advance via the chip. you can change every aspect of the timing via the chip. on my car, i actualy use a switchable PROM, i burned 8 configurations, the fuel curve maps the same on all of them, and set the initial advance in 1* increments, so i can adjusting timing on the fly, from inside the car

i found my motor also really likes 6* initial advance too. change a couple of small things in the timing curve, but it is pretty much the stock spark tables, with 6* advance, i can run 87octane with no knock, but at 8*, it does knock under load even with 92 octane.

 

i was referring to the actual number of degrees the distributor will advance. for example, my distributor advances 25 degrees. with an initial advance setting of 0 degrees and 25 degrees of distributor advance, total advance is 25 degrees. with an initial setting of 6 degrees of advance and 25 degrees of distributor advance, total advance is 31 degrees. correct?

i didn't know you could change initial advance with a chip. what switchable prom are you using?

 

there is a main spark bias setting in the chip, it is put in there because the chip can basicly not handle negative numbers, which it needs for retarding the timing due to knock. stock it is a 20* bias, so realisticly you subtract 20* from the total timing that is added in the chip. combined with the initial timing set for the engine. you can change that bias to like 14*, so it takes the total spark in the tables, and only subtracts 14* from it, instead of 20, it will do that GLOBALY for any cell, at any temp, even at idle, basicly giving you 6* of initial advance via the chip, with the dizzy and engine still timed to 0*, you really aren't runing at 0* when you are under computer control, set you timing to 0*, and re-connect the ESC, now fire your timing light, you should be in the 20* to 22* neighborhood at idle, by changing the spark bias, you woul dbe in the 26* - 28* range at idle, even though you timing is set to 0*.

if that made any sense.

BTW, i use a craig moates switchable prom adapator , unfortinatly he no longer makes them. right now i have 8 bins laoded, with the main spark bias set from 20* to 12* , which gives me up to 8* of timing at the turn of a switch

 

LO3s don't have fast-burn combustion chambers, so they need more ignition timing advance to make optimum power.

Keep in mind that GM had to test and program the ignition base timing for a wider range of operating conditions than you are experiencing in a single night-time dyno test in late Sept. IOW they had to have no knock with 87 octane under WOT loading conditions at DPG in Arizona in an early afternoon Summer day (worst case); IOW when the airtemp was around 105+ deg F.

I wouldn't be surprised if those test conditions at DPG were exactly where the factory 0 deg advance came from for the LO3, the worst case hot operating condition with some margin built-in for elevated carbon in the chambers, when the compression ratio is artificially raised by 0.5. FWIW.

 

ok, i'm a total dumbass. what are:

IOW

DPG (desert proving grounds?)

FWIW?

 

I think IOW is I often wonder.

FWIW ...I have no idea what that one means either?

People are damned lazy..I hate when people write @ for non-email address occasions..just write "at"!

 

FWIW means for what its worth....there is a link to a page with all the common abreviations in the FAQ board

 

DPG = (GM) Desert Proving Grounds
FWIW = for what it's worth
FSM = factory service manual
FYI = for your information
HTH = hope this helps
IOW = in other words
YMMV = your mileage may vary

among many others.

 

I would find this to be true in the old days, where advance was a vacuum and weights affair. But with computer control, and the array of coolant temp and intake air temp sensors, GM should have been able to dial back the timing under extreme circumstances, but not adversely affect performance during more mild conditions.

 

My comment referred to an owner's practice of manually advancing the base timing by 4 or 6 or more degrees beyond stock. The computer won't necessarily handle that under all conditions & loads, especially handing it fast enough to avoid damage -- and that's why GM set it where they did. Otherwise, if what you suggest were true, then GM would have advanced the base timing even on LO3 cars to obtain the extra dyno-proven power (shown previously in this thread) as well as to increase the fuel economy.

 

Well I don't particularly like the whole advancing the base timing thing either, especially as it applies to extreme conditions. BUT, during the conditions it DOES work, GM could have added more timing in the chip (with the base still at 0) then as temps rise, pull it back out.