Ignition timing question?

[jbod]

Have an interesting question i have had mixed answers on

Can you advance the ignition timing via the distributor for increase in power? I havent planned to i was more curious as to does it actually work

The factory ecu pulls timing back on a hot day or on a bad batch of fuel to save the engine, then a aftermarket ecu is tuned an it keeps the same timing all day everyday. A hot day or bad batch of fuel can bring on knock

If i recall when i looked at my old power fc through a laptop timing is advanced with the revs, say 10ish at idle to 25ish at high revs

So can one sinply advance the distributor timing by simply turning the cap? Im trying to work out how you would advance it but then where does that leave the timing at idle? Will the factory ecu pull timing back if its too far

Someone was telling me to simply do this on a 3sgte however it sounded abit hocus pocus and was curious to know how itd all work! Hope i have explained it all well

[Lloyd]

Depending on the engine, yes you can get more power by simply turning the distributor. It does depend a lot on the fuel you're running for various reasons. The timing is usually advanced when higher octane fuels are used as they are less likely to knock with higher compression engines, and higher octane fuels burn slower. More timing advance (with higher octane fuels) means you end up with the highest cylinder pressures when the piston is just passing TDC (more timing meaning the slower burning fuel is ignited earlier).

Generally on the 90s Toyotas you jump the diagnostic terminals before playing with the timing which resets the base/idle timing.

[jbod]

Ok i see. Say if you turned the distributor x amount ie 10degrees. Would this mean idle is now 20degrees btdc? And 10 degrees ontop ontop of watever factory timing is at higher rpm? Would be interesting to play around with tho i would rather not ho break anything. Haha!

[jondee86]

I had a stock smallport 4AGE on the dyno, and the operator dialled
in a couple of degrees of advance... it made zero difference. Most
engines are pretty well optimised, as the factory is not going to leave
easy power on the table !!!

Cheers... jondee86

[rollaholic]

Ok i see. Say if you turned the distributor x amount ie 10degrees. Would this mean idle is now 20degrees btdc? And 10 degrees ontop ontop of watever factory timing is at higher rpm? Would be interesting to play around with tho i would rather not ho break anything. Haha!

most cars with timing that can be adjusted like this will have a specific procedure for doing so. in my experience its never as simple as just turning the distributor. you'll need to follow this procedure to get consistent results, and you'll need a timing light to see how much your adjustments are changing the base timing.

like jondee said most engines are fairly well sorted on this front already. the reason it costs lots of money to make more power is because all the free / easy stuff has already been done by the factory

[matt dunn]

most cars with timing that can be adjusted like this will have a specific procedure for doing so. in my experience its never as simple as just turning the distributor.

On a Toyota you need to bridge the Diagnostic connector,
then you need to check/adjust the TPS so that the ecu knows it is at idle,
then you need to ensure the engine is at temp and the correct idle speed,
then you use a timing light to set it to spec's,

Or you cheat,
get a scantool,
read current ign advance off the live data
and just adjust it to that,
( on toyota's is usually spec anyway unless something else is off)

[Flannelman]

A few years ago now, I had some dyno time and fiddled with the timing. The Levin's 20V Silvertop responded with a power increase of 2%. Torque was also up through out the torque curve from right off idle to rev cut. The torque hole between 3700-4500 was filled too.

On the road, there was greater throttle response. Less gas was needed to generate the same acceleration so fuel economy got better.

While this description is accurate, if I was to say that the 2% increase was only 1.6kW and the torque only 10Nm average, they do look and sound disappointing. However, that extra urge in the first 20% of throttle made the numbers feel so much more.

Since then, I now time by ear. I don't recommend doing this for all cars.

1, Loosen distributor bolt
2, Start engine
3, Bring engine up to 2000-2500rpm (or get a friend to do it form drivers seat)
4, (On a 4AGE 20V anti-clockwise is retard) Retard timing, engine revs should fall.
5, Advance timing until engine revs stop rising. This is the new timing mark.

[Lith]

^ I did something similar on the dyno with my old Honda Domani, not how I'd normally go about things but I didn't really want to spend any money but at the same time felt like having a bit more lulz with it. I think we saw perhaps around 5% more torque at points in the rev range, it made a noticeable improvement to response and general acceleration. Did that and freed up the intake and it actually became surprisingly amusing to drive

[jbod]

Interesting thanks for all the good oil. What i am trying to work out is if factory timing was 10degrees at idle, and say for argument sake 15 at high revs, how would you encrease it in a way that would allow more advance timing at high revs, but the same 10 degrees at idle which is more or less required to run!? I looked at an article where there was a clutch inthe distribuor and changin the spring to a softer one allowed for quicker advancing over the rev range

[Grrrrrrr!]

Thats only for old mechanical timing (points). With EFI and ignition done by the computer the only adjustment you have is moving the entire curve by rotating the dizzy, or get a piggyback or standalone ECU that you can program.

[jbod]

I should have put two and two together tht it was on an old v8! I see so the ignition is increased in uniform. Oh well question answered. I was curious to see if advancing could be done without a aftermarket ecu on a efi engine. Cheers!

[jondee86]

When the ECU is controlling the ignition timing, it looks at several
parameters to determine the correct advance under any particular
combination of conditions. Engine load, rpm, temperature, rate of
acceleration required, and maybe a few others that I can't think of
just now

The ECU will use the data programmed into it at the factory to set
the correct (instantaneous) advance to achieve the best engine
performance at each moment. Typically, a small engine may idle
at 15 deg, drop to 10 deg if you open the throttle suddenly at low
rpm, and rise to 40 deg if you close the throttle at high rpm.

The factory will spend thousands of hours developing the best
ignition map for an engine. And that map has to satisfy mum
driving to the mall, or dad trying to beat that ricer away from the
lights So, inevitably, there will be some compromise of outright
power in favour of driveability.

Yes, there probably are a few extra ponies to be gained by fitting a
programmable ECU or piggyback. However there is a good chance
that you will lose some of the ease of starting, smooth idle,
economy, emissions compliance and general all-round competence
of the factory ECU. And you will need dyno time to get the best out
of your modifications. Plus, advancing the timing will put you just a
little bit closer to that fine line between maximum torque and
detonation... so yeah, a bit more to it than just turning the dizzy

Cheers... jondee86