ReGap Your Spark Plugs to Improve Performance

[Mona-vie]

Esp. when carrying more people with AC and low RPM.

 

Side gap + regapping your spark plugs will help to improve performance by quite a noticeable amount. My original gap is 1.1mm and I increase it to 1.4mm. The difference is very noticeable. Tried with 4 people + AC and under hot day, the car performs well. I can't really feel the extra weight of the car at all. Even going up slope is not a problem (mine is manual).

 

Of course, you have to experiment whats the max gap for your car. If you experience misfiring under WOT at high RPM, this means the gap is too big already.

 

One cheap solution to get reduce misfiring problem is to install an ignition booster. Not those VS, its those which boost the voltage to ~16V. With slightly more primary voltage to your coils, you will achieve a higher secondary voltage to your plugs, hence resolving the misfiring issue (of course there is a limit as well).

[SimonTan]

When normally people say regap...it's to make the gap closer due to the material wear.

But you advice widening the gap......Interesting theory!

 

[Yewheng]

http://www.custom-car.us/ignition/spark-plug/gap.aspx

 

interesting article

Edited June 16, 2011 by Yewheng

[Good-Carbuyer]

  On 6/16/2011 at 1:09 AM, Mona-vie said:

Esp. when carrying more people with AC and low RPM.

 

Side gap + regapping your spark plugs will help to improve performance by quite a noticeable amount. My original gap is 1.1mm and I increase it to 1.4mm. The difference is very noticeable. Tried with 4 people + AC and under hot day, the car performs well. I can't really feel the extra weight of the car at all. Even going up slope is not a problem (mine is manual).

 

Of course, you have to experiment whats the max gap for your car. If you experience misfiring under WOT at high RPM, this means the gap is too big already.

 

One cheap solution to get reduce misfiring problem is to install an ignition booster. Not those VS, its those which boost the voltage to ~16V. With slightly more primary voltage to your coils, you will achieve a higher secondary voltage to your plugs, hence resolving the misfiring issue (of course there is a limit as well).

Use the maximum gap for my previous Kelisa. I believe yours still got room for improvement (laugh)

[Good-Carbuyer]

  On 6/16/2011 at 1:43 AM, SimonTan said:

When normally people say regap...it's to make the gap closer due to the material wear.

But you advice widening the gap......Interesting theory!

Most people follow commercial theory only.

[Good-Carbuyer]

  On 6/16/2011 at 1:52 AM, Yewheng said:

http://www.custom-car.us/ignition/spark-plug/gap.aspx

 

interesting article

No mention about ambient temperature?

No mention about high ambient humidity?

No mention the ignition system referred to?

Academic theory?

[Mona-vie]

  On 6/16/2011 at 2:05 AM, Good-Carbuyer said:

No mention about ambient temperature?

No mention about high ambient humidity?

No mention the ignition system referred to?

Academic theory?

 

What affects spark gap is the air pressure inside the combustion chamber rather than your humidity or ambient.

 

Spark occurs most easily at complete vaccum (lowest voltage needed). More air/fuel will make spark harder to occur (higher voltage needed). Thats why highly boosted cars sometimes uses CDI in order to prevent misfiring. Boosted cars also runs much smaller gap compared to NA to due higher pressures in combustion chamber.

 

How much you can increase your gap is determined by your ignition coil as well as primary voltage. Some coils are designed to produce higher secondary voltage while others are lower. As the car manufacturer does not state any specs for the coils, only way is by trial and error.

 

By, gapping your plugs is not something that is new. It has been around for decades. Racing cars do not use stock or standard rated gaps for the engine. they run tests (dyno, measure peak cylinder pressure, track test etc) in order to determine the best gap for the plugs. Also different cylinders have different optimal gap.

[Good-Carbuyer]

  On 6/16/2011 at 2:30 AM, Mona-vie said:

What affects spark gap is the air pressure inside the combustion chamber rather than your humidity or ambient.

 

Spark occurs most easily at complete vaccum (lowest voltage needed). More air/fuel will make spark harder to occur (higher voltage needed). Thats why highly boosted cars sometimes uses CDI in order to prevent misfiring. Boosted cars also runs much smaller gap compared to NA to due higher pressures in combustion chamber.

 

How much you can increase your gap is determined by your ignition coil as well as primary voltage. Some coils are designed to produce higher secondary voltage while others are lower. As the car manufacturer does not state any specs for the coils, only way is by trial and error.

 

By, gapping your plugs is not something that is new. It has been around for decades. Racing cars do not use stock or standard rated gaps for the engine. they run tests (dyno, measure peak cylinder pressure, track test etc) in order to determine the best gap for the plugs. Also different cylinders have different optimal gap.

Lack of manufacturer's spec leads most people to follow the norm. I find CDI worked best with Kelisa engine.

[Celicar]

Sounds dangerous to a layman like me. Unless significant improvement, think I'll just leave the plugs alone.

[Mona-vie]

  On 6/16/2011 at 4:02 AM, Celicar said:

Sounds dangerous to a layman like me. Unless significant improvement, think I'll just leave the plugs alone.

 

No, this is not meant for novice. You should only do it if you have some knowledge about cars and electrical stuff. Of course, need to know how to remove spark plugs as well. Else if you break the porcelain jialat.

[Tanhangkiang]

  On 6/16/2011 at 1:09 AM, Mona-vie said:

Esp. when carrying more people with AC and low RPM.

 

Side gap + regapping your spark plugs will help to improve performance by quite a noticeable amount. My original gap is 1.1mm and I increase it to 1.4mm. The difference is very noticeable. Tried with 4 people + AC and under hot day, the car performs well. I can't really feel the extra weight of the car at all. Even going up slope is not a problem (mine is manual).

 

Of course, you have to experiment whats the max gap for your car. If you experience misfiring under WOT at high RPM, this means the gap is too big already.

 

One cheap solution to get reduce misfiring problem is to install an ignition booster. Not those VS, its those which boost the voltage to ~16V. With slightly more primary voltage to your coils, you will achieve a higher secondary voltage to your plugs, hence resolving the misfiring issue (of course there is a limit as well).

 

 

check out the bosch ir fusion plugs, i heard somewhere, it is 1.6mm by default.

 

http://www.mycarforum.com/index.php?showtopic=2631025

[5936]

Wow, experiment came back liao.

 

YES, I agree, and I have tried that, and paid a heavy price for this experiment.

 

The measurement of performance is only yourself, unless you send in for dyno tests.

 

I tried both reducing the gap as well as increasing the gap spaces, until the best gapping is achieved.

After every regap, go through the "test drive circuit" of hills, highway, etc.

 

Be very careful, with so many opening of and reinsgtalling of spark plugs, there is high possibility of CROSS treading.

Because, I had 1 spplug crosstreaded, and internal tread was damaged...

 

If you can do it when plugs are cold. if you can resist temptation.

 

Have fun.

 

 

 

 

[Mona-vie]

  On 6/16/2011 at 12:02 PM, 5936 said:

Wow, experiment came back liao.

 

YES, I agree, and I have tried that, and paid a heavy price for this experiment.

 

The measurement of performance is only yourself, unless you send in for dyno tests.

 

I tried both reducing the gap as well as increasing the gap spaces, until the best gapping is achieved.

After every regap, go through the "test drive circuit" of hills, highway, etc.

 

Be very careful, with so many opening of and reinsgtalling of spark plugs, there is high possibility of CROSS treading.

Because, I had 1 spplug crosstreaded, and internal tread was damaged...

 

If you can do it when plugs are cold. if you can resist temptation.

 

Have fun.

 

As I have mentioned in my previous post, this is not meant for novice. Knowing how to correctly remove and install spark plugs is a must. Else you should not even try it out.

[Mona-vie]

  On 6/16/2011 at 11:37 AM, Tanhangkiang said:

check out the bosch ir fusion plugs, i heard somewhere, it is 1.6mm by default.

 

http://www.mycarforum.com/index.php?showtopic=2631025

 

I have tried it out quite sometime back. Nay, nothing fantastic.

[Tanhangkiang]

  On 6/16/2011 at 1:21 PM, Mona-vie said:

I have tried it out quite sometime back. Nay, nothing fantastic.

 

 

Thx for the sharing.

 

Most probably, weak ignition system can close up the gap rather than widening it.

 

1.0 or 1.1mm maybe is better.

[Mona-vie]

  On 6/16/2011 at 1:31 PM, Tanhangkiang said:

Thx for the sharing.

 

Most probably, weak ignition system can close up the gap rather than widening it.

 

1.0 or 1.1mm maybe is better.

 

Its using surface gap so its ok to be wider. But 4 grounding tips is seriously over kill. There is slight performance boost over stock NGK/Denso iridium plugs but nothing fantastic about it to justify higher price. regapping my NGK plugs provides just as good performance for far less.

 

 

One good surface gap plug is Brisk Premium LGS but the price is crazy.

 

After trying out so many brands, I feel NGK is still the best value for $$$. $60 for 4 iridium plugs.

[Yeobh]

If you have this spark plug gap tester you can cut the trial and error method and save alot of time doing test run.

[Yeobh]

If you are using stock ignition system, you can increase the gap to a certain extent on condition the coil/ignitor and spark cables are perfect condition. Most ignitor/coil will generates about 25kv and due to spark plug cable resistance etc the voltage that jump the spark plug gap maybe only about 15KV.