spark plug gap


Asked by Oct 20, 2008 at 06:44 PM about the 2005 Ford Mustang GT Deluxe

Question type: Maintenance & Repair

What is the spark plug gap recommended for the magna supercharger installation for the 2005 Mustang GT to prevent detonation?

So far I have two different answers. From magna installation manual with the supercharger they recommend original gap, but in an article published in Modified Mustang the Magna supercharger factory rep ended up changing the gap on the plugs. Sp which one is it?

6 Answers


If you're using platinum plugs, only gap them if you want to destroy the plug and go buy new ones. If you're using copper plugs, you should use what Magna says.


What were the two gap ranges. When vehicles are boosted you want to run a smaller gap, but I would like to hear what the two of them are.


Sorry for the late reply Andrew, I had difficulty locating the article from my magazine collection. Anyhow, in the "Mustang and Fast Ford Mag, June 2008 they talk about all blowers. The one in question here, is suggested by the factory rep from magnusson to change the original spark plug ( HT1 gapped at 0.045-inch) to HT0's gapped at 0.030 inch. They mention that anytime more than 4 pounds of boost is seen in force induction engine the spark has tendency to be blown out, hence the reduced gap as you mentioned as well. In the installation book for the same magnusson blower, they recommend to keep the original spark plugs. So I am a little puzzled here. Why would the installation manual not recommend a smaller gapped plug?


Ok...did they say keep the original spark plugs or the original spark plug gaps? If they say spark plugs you may use the original spark plugs just make the gap tighter. When they talk about the spark being blown out, that is true. The reason you have a such a substantial gap change is going from a naturally aspirated motor to a "boosted" motor. I have a Mitsubishi Eclipse GST I have upped the boost and in doing so lessened the gap. Im not familiar with Mustangs but do you have system to datalog with. You wil definately know if your knocking. 0.30 doesnt sound too bad.


I am going to go with the 0,30 gap and see where it goes. I will let you know how much extra ponies I am putting to the pavement after this blower is installed. I can not wait to see this monster awaken my 4.6L.


Make sure you get those HT0 plugs. They will be a step colder than stock and then gap them at 0.030 Good Luck and have fun.

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