NorCal90

I am wanting to advance the ignition timing on my 90 NA and was curious how I am supposed to tell how many degrees I've advanced. Also, do I need to run higher octane after doing this? I am planning on advancing the timing 10 deg.

buttsjim

I'm so full of low-tech answers to this question, it makes me wonder if I understand what you're asking...

But, for 10* (at the shaft) you could use a protractor, and measure 10 degrees clockwise. Or, use a soft tape measure to measure your pulley circumference, multiply by 10/360, and measure the resulting distance clockwise from the leading timing mark. Or, measure the distance between the 2 existing marks on your pulley, multiply by 2/3, and measure that distance clockwise from the leading mark. Or, you can order a pizza cut into 36 slices, hold one slice up against the pulley, and trace along the right edge (sorry for the bad joke, but my mind is racing, and I can't stop it).

As a reference, you should have two existing marks on your pulley. The one on the right is the leading mark, set at 5* after top dead center; the one on the left is 20* ATDC. Ten degrees advance would put you at 5* before top dead center.

I don't know the pros and cons of advancing the timing, but it seems to me that doing so will bring your knock sensor more into play. It will compensate for lower octane gas, but it does that by retarding your timing.

coldfire

iTrader: (1)

i am also wondering about this. buttsjim's suggestions seem like they could work. i wonder if maybe there is a way to mark different colours on the pulley for different degrees, so then you can just recognize the timing that way?

also this is a 90 NA, so i don't think he will have a knock sensor?? but on a turbo i wouldn't think you would want to fool around too much with advancing the timing...

when i was adjusting timing with pretty much stock everything, i found that going more retarded than stock resulted in less acceleration but a smoother power delivery. however advancing timing gave more acceleration, but the car seemed jerky and throttle response was finicky...i really wouldn't change it from stock if your car is more or less stock, but i will be going on the dyno this summer and i will fool around with the timing a bit to see what i can get...mind you i have SAFC, intake and exhaust mods so that's why i want to try playing around with it.

Turbonut

iTrader: (1)

Ted's response to this question a while ago for Turbo and N/A::

Don't mess around with advancing the ignition timing on a stock ECU.
You'll run into more dangers than it's worth.

With a stand-alone EMS, it's a difference story.

In general, ignition timing advance does not increase power as drastically as with piston engines.  Those 1 to 5hp increase is not worth the 5 to 10 degrees of increased ignition timing that can kill your engine, especially on a turbo one.

-Ted

Advancing the ignition timing on a stock ECU will usually mean "moving the CAS".  If you move the CAS, this means ALL ignition timing will be moved this amount.

The stand-alone EMS allows you to change ignition timing where you want / need it and not where you don't.  In general you can run up to 10-degrees more timing in very low boost ranges (at "0" up to 2-4psi of boost), but when you start to shoot for 10psi or more, the stock ECU ignition timing of about 18BTDC is more than adequate for pump gas.

For NA, you can get away with running slightly more advanced ignition timing via the CAS.  Start with 3-degrees more and see if it likes it.  Run it up to 5-degrees to see if you don't run into detonation problems.  BE AWARE YOU'RE TAKING A RISK OF ENGINE DAMAGE IF YOU TRY THIS.  This will almost require you to run "premium" octane in your NA.

NorCal90

thanks for the input all. i found an article here stating that some team got 1 horsepower for each degree advanced timing untill 10 deg where the gains stopped but i guess they had a standalone. if anyone knows the thread i am talking about, posting a link would be nice as i cannot find it for the life of me