retard timing= better low end power but loose high end

advance timing=better high end but loose low end.

i got my timing retarded as of now because i am scared to detonate. is it safe to keep it retarded for daily driving?

 

advance means move closer to tdc, and retard is farther, right?

 

that is obvious but not wat i asked.

 

that was just a ??? i had...retard is safer than advance

 

I guess you are talking about ignition timing? From what I have seen, a safe increase and proper increase in ignition timing over stock can add to the whole curve.


Jason

 

That is completely wrong. Retarding the timing will give you better top end power and advancing the timing will give you better low end power.

Again, that is a VERY general statement - as advancing or retarding the timing affects the entire RPM band.

However, on built motors with high compression and/or boost, pulling timing up top (retarded) generally yeilds more power, because it is detonating up top otherwise.

The purpose of advanced timing down low is way better throttle response under load.

Try setting your timing ALL the way retarded and try to launch from a dead stop, then set your timing back to stock and do the same... You'll see.

Side note: turning the distributor towards the FRONT of the car = retard timing.

more info on timing here: http://www.c-speedracing.com/howto/timing/timing.html

 

So why do engines have a mechanical ADVANCE for the distributor....
higher RPM more advance...
when you car running advanced ignition you use race gas.......

it seems like everyone is advancing their timing on N/A engines..

 

Actually, engines have ELECTRONIC advance that is controlled by the ecu which is added to the mechancil (physical) advance set by the distributor.

If you look at the ignition tables for any honda ecu, you will notice that as RPM and load (TPS) increases, total ignition advance DECREASES. Generally on a DOHC vtec setup, you will find ignition advance in the area of 35-40deg at low rpm low throttle position and at high rpm (redline) and high throttle (WOT), ignition advance drops to 20-25deg.

 

Well, I'm gonna disagree with everyone...

IMO, this is not a high vs low tradeoff. It's a power vs safety one. Retarding the timing reduces the amount of energy you can make. It moves the ignition away from TDC, reducing the chance of detonation. There is NO power gain by doing this... you lose power across the entire RPM range. Retarding the timing also increases your cylinder temperatures. This usually isn't a problem on NA cars, but could be, and is magnified with FI.

Increasing the timing makes more power... across the rpm band. The downside is the increased chance of detonation. Get your air/fuel mixture where you want it, then turn up your timing as high as possible while avoiding detonation.

 

First off, advancing the timing is firing the spark plug earlier, that is, further from TDC. Seems that everyone was either wrong or confused by everything because of this.

"If the point of ignition it too far before TC, that is, too advanced, then the combustion will complete roughly at TC and this will be the point of peak pressure. That is the worst situation for knocking, because it leads to the highest pressures and temperatures".
-Engines, an Introduction
John L. Lumley (good book!)

Generally you want to advace the timing as rpms increase. The piston moves faster, so by firing earlier the peak pressure will be reached at around 15deg after TDC (the best point).

Overdoing timing advance will lead to peak pressures too high and therefore detonation, or just loss of power due to the fact that peak pressures are not reached at the optimum point.

From what I understand, FI engines are usually over-retarded to avoid detonation. So generally, advancing them will lead to more power or a blown engine, whichever comes first....


[Modified by Lsos, 10:15 PM 2/14/2002]