Spark Plug Life Span?

King Snake · 09-14-2000, 07:43 AM

How often should the spark plugs in 96-98 Mustangs be changed? I asked the dealer and was told that the factory plugs are platinum and should last for 100,000 miles. I'm a little leary of running plugs that long. My car has 40,000 miles and I am wondering if I will benefit from installing a fresh set of plugs. The factory plugs (Motorcraft Platinum) cost around $8 a piece.

Thanks for the feedback!

------------------
'97 Cobra, K&N, 3.73s, Rio Red

dirtyGT · 09-19-2000, 08:35 PM

My dads a mecanic and he always said to change them at about 50,000 or when ever it feels like it needs them and if your wondering if it does i'd say go ahed and change them

King Snake · 09-20-2000, 06:01 AM

Thanks for the advice! I think I am just going to pull one out and look at it, and if it doesn't look really good I will change them all...

------------------
'97 Cobra, K&N, 3.73s, Rio Red

Mustang92 · 09-20-2000, 07:18 AM

I just changed mine out with 24K miles on them. They didn't look too bad, one was a little fouled out, but instead of replacing them with platinum's I went with a copper plug. I want something in my car made for performance not longevity.

------------------
00 GT, K&N, 2 chamber Flowmasters, MAC Tree Killer, Pullies, UPR shifter, Weld Pro Stars, Nitto DR’s,MM#100 13.48@99.27(1.99 60ft)
88 LX coupe X-FHP, 12pt Cage, UPR K-member, 31 spline rear, full spool, more to come

King Snake · 09-20-2000, 08:04 AM

What kind of plugs did you use, and do you get better performance out of copper plugs? I thought the platinums were suposed to perform better as well as last longer. Could you tell your car ran any better with the new plugs? I know it's hard to tell; my car seems to run better after I wash it...

------------------
'97 Cobra, K&N, 3.73s, Rio Red

RAS 96GT · 09-20-2000, 08:54 AM

I replaced mine after 35,000 miles w/NGK TR55 platinum. $6.29- Freaking expensive compared to the copper version. but I figure that platinum came out thats what I'll put back in. Then I found very useful info on NGK's site and read that its O.K. to put coppers in there. You might change them out more often, but at $1.85, thats what I'll do next time. No need to wait to roll over six digits to change them out. Should of done mine at 30.

Hope this helps.

------------------
-Rich Lazer Red 96GT, K&N, Steeda Pullies, Mobile 1 Synth, NGK TR55s,Pro 5.0 Shifter, 3.27 Gears, and more to come.

Moxie · 09-20-2000, 10:37 AM

Copper is a very good conductor of electricity- much better than platinum. For performance, copper is the only way to go.

------------------
Moxie Racing

Moderator, TealNet

The artist formerly known as virtspeed

Mustang92 · 09-21-2000, 06:50 AM

Didn't really notice much of a difference plus I installed pullies at the same time. I know the couldn't have hurt and like some other have said copper plugs are more for performance since the conduct better.

I used the NGK TR-55.

King Snake · 09-21-2000, 07:58 AM

Are you saying you could not tell a difference with the pullies? I know the plugs will not make a noticeable increase in power, but the pullies should.

------------------
'97 Cobra, K&N, 3.73s, Rio Red

Mustang92 · 09-21-2000, 10:05 AM

Let me re-phrase that driving on the street it feels a little stronger. But I like to base my gains on my et's and MPH at the track. I run my car alot, about 170+ passes since last November. Without the pullies or plug change my best was a 13.66, then after the changes I matched my best twice but never beat it. My MPH went up a little but my MPH seems to be off based on my 1/8 MPH, I believe it's due to the fact that I'm holding the car in 3rd going through the traps.

Since then I've been playing with using resistors in the IAT sensor and have improved on my best by nearly 2 tenths. Some of that I'm sure is from the pullies but I have no idea how much.

So yes you will gain with the pullies but due to the screwy weather down here it's hard for me to really say how much.

------------------
00 GT, K&N, 2 chamber Flowmasters, MAC Tree Killer, Pullies, UPR shifter, Weld Pro Stars, Nitto DR’s,MM#100 13.48@99.27(1.99 60ft)
88 LX coupe X-FHP, 12pt Cage, UPR K-member, 31 spline rear, full spool, more to come

King Snake · 09-21-2000, 10:33 AM

I assume that by tweaking your intake air temp sensor you are attempting to fool the EEC that your air charge is cooler than it actually is thereby resulting in the addition of more fuel. I can see how this can have an advantage over changing the t-stat because actually running your engine cooler can cause premature engine wear.

Am I on the right track?

------------------
'97 Cobra, K&N, 3.73s, Rio Red

Mustang92 · 09-21-2000, 11:40 AM

Yes and no. By using the resistor you fool the computer by making it think it is actually cooler outside than it is which will increase fuel and timing, timing being the key. I also have a 180* thermostat and it will not cause premature engine wear. Only thing it does is opens at 180 instead of 192 thus it takes longer for the motor to get to 192. So effectivity your delaying the motor from heating up to quickly.

------------------
00 GT, K&N, 2 chamber Flowmasters, MAC Tree Killer, Pullies, UPR shifter, Weld Pro Stars, Nitto DR’s,MM#100 13.48@99.27(1.99 60ft)
88 LX coupe X-FHP, 12pt Cage, UPR K-member, 31 spline rear, full spool, more to come

King Snake · 09-21-2000, 11:46 AM

The 180* thermostat will keep your engine temperature AT 182* and should not allow it to get any warmer than that. The t-stat actually regulates the coolant flow; in other words, it is not either open or closed but can vary the amount of coolant that flows through it. I like the idea of tweaking your IAT. Does its resistance increase or decrease with an increase in temp? And have you tried a pot instead of a resistor?

------------------
'97 Cobra, K&N, 3.73s, Rio Red

Mustang92 · 09-21-2000, 02:07 PM

I have an autometer gauge and even with the 180* thermostat it reaches 192* it just takes longer to get there. With a better cooling system it would stay closer to what your saying. Maybe the GT's just have a lower cooling capacity. At least that is what I'm seeing my case.

The resistance of the resistor is a fixed temperature and after 3-5 cold starts the EEC will find it and give a MIL. So it's more of a temporary track only item. This is a trick use by alot of people for some time in earlier mustangs, camaro, etc so to be honest I'm not even sure about trying anything else to trick the EEC. There is one guy on the Corral, Casper he sells custom boxes that allows you to adjust which resistor you want and even an auto mode that you leave it in on start up to prevent receiving the MIL.

------------------
00 GT, K&N, 2 chamber Flowmasters, MAC Tree Killer, Pullies, UPR shifter, Weld Pro Stars, Nitto DR’s,MM#100 13.48@99.27(1.99 60ft)
88 LX coupe X-FHP, 12pt Cage, UPR K-member, 31 spline rear, full spool, more to come

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09-14-2000, 07:43 AM	#1
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	Spark Plug Life Span? How often should the spark plugs in 96-98 Mustangs be changed? I asked the dealer and was told that the factory plugs are platinum and should last for 100,000 miles. I'm a little leary of running plugs that long. My car has 40,000 miles and I am wondering if I will benefit from installing a fresh set of plugs. The factory plugs (Motorcraft Platinum) cost around $8 a piece. Thanks for the feedback! ------------------ '97 Cobra, K&N, 3.73s, Rio Red

09-19-2000, 08:35 PM	#2
dirtyGT Registered Member Join Date: Feb 2000 Location: INDIANA Posts: 658	My dads a mecanic and he always said to change them at about 50,000 or when ever it feels like it needs them and if your wondering if it does i'd say go ahed and change them

09-20-2000, 06:01 AM	#3
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	Thanks for the advice! I think I am just going to pull one out and look at it, and if it doesn't look really good I will change them all... ------------------ '97 Cobra, K&N, 3.73s, Rio Red

09-20-2000, 07:18 AM	#4
Mustang92 Drag Racer! Join Date: Nov 1999 Location: Lake Worth, FL USA Posts: 757	I just changed mine out with 24K miles on them. They didn't look too bad, one was a little fouled out, but instead of replacing them with platinum's I went with a copper plug. I want something in my car made for performance not longevity. ------------------ 00 GT, K&N, 2 chamber Flowmasters, MAC Tree Killer, Pullies, UPR shifter, Weld Pro Stars, Nitto DR’s,MM#100 13.48@99.27(1.99 60ft) 88 LX coupe X-FHP, 12pt Cage, UPR K-member, 31 spline rear, full spool, more to come

09-20-2000, 08:04 AM	#5
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	What kind of plugs did you use, and do you get better performance out of copper plugs? I thought the platinums were suposed to perform better as well as last longer. Could you tell your car ran any better with the new plugs? I know it's hard to tell; my car seems to run better after I wash it... ------------------ '97 Cobra, K&N, 3.73s, Rio Red

09-20-2000, 08:54 AM	#6
RAS 96GT Registered Member Join Date: Aug 2000 Location: Chicago,IL Posts: 6	I replaced mine after 35,000 miles w/NGK TR55 platinum. $6.29- Freaking expensive compared to the copper version. but I figure that platinum came out thats what I'll put back in. Then I found very useful info on NGK's site and read that its O.K. to put coppers in there. You might change them out more often, but at $1.85, thats what I'll do next time. No need to wait to roll over six digits to change them out. Should of done mine at 30. Hope this helps. ------------------ -Rich Lazer Red 96GT, K&N, Steeda Pullies, Mobile 1 Synth, NGK TR55s,Pro 5.0 Shifter, 3.27 Gears, and more to come.

09-20-2000, 10:37 AM	#7
Moxie Registered Member Join Date: Aug 2000 Location: Plymouth, MI Posts: 254	Copper is a very good conductor of electricity- much better than platinum. For performance, copper is the only way to go. ------------------ Moxie Racing Moderator, TealNet The artist formerly known as virtspeed

09-21-2000, 06:50 AM	#8
Mustang92 Drag Racer! Join Date: Nov 1999 Location: Lake Worth, FL USA Posts: 757	Didn't really notice much of a difference plus I installed pullies at the same time. I know the couldn't have hurt and like some other have said copper plugs are more for performance since the conduct better. I used the NGK TR-55.

09-21-2000, 07:58 AM	#9
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	Are you saying you could not tell a difference with the pullies? I know the plugs will not make a noticeable increase in power, but the pullies should. ------------------ '97 Cobra, K&N, 3.73s, Rio Red

09-21-2000, 10:05 AM	#10
Mustang92 Drag Racer! Join Date: Nov 1999 Location: Lake Worth, FL USA Posts: 757	Let me re-phrase that driving on the street it feels a little stronger. But I like to base my gains on my et's and MPH at the track. I run my car alot, about 170+ passes since last November. Without the pullies or plug change my best was a 13.66, then after the changes I matched my best twice but never beat it. My MPH went up a little but my MPH seems to be off based on my 1/8 MPH, I believe it's due to the fact that I'm holding the car in 3rd going through the traps. Since then I've been playing with using resistors in the IAT sensor and have improved on my best by nearly 2 tenths. Some of that I'm sure is from the pullies but I have no idea how much. So yes you will gain with the pullies but due to the screwy weather down here it's hard for me to really say how much. ------------------ 00 GT, K&N, 2 chamber Flowmasters, MAC Tree Killer, Pullies, UPR shifter, Weld Pro Stars, Nitto DR’s,MM#100 13.48@99.27(1.99 60ft) 88 LX coupe X-FHP, 12pt Cage, UPR K-member, 31 spline rear, full spool, more to come

09-21-2000, 10:33 AM	#11
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	I assume that by tweaking your intake air temp sensor you are attempting to fool the EEC that your air charge is cooler than it actually is thereby resulting in the addition of more fuel. I can see how this can have an advantage over changing the t-stat because actually running your engine cooler can cause premature engine wear. Am I on the right track? ------------------ '97 Cobra, K&N, 3.73s, Rio Red

09-21-2000, 11:40 AM	#12
Mustang92 Drag Racer! Join Date: Nov 1999 Location: Lake Worth, FL USA Posts: 757	Yes and no. By using the resistor you fool the computer by making it think it is actually cooler outside than it is which will increase fuel and timing, timing being the key. I also have a 180* thermostat and it will not cause premature engine wear. Only thing it does is opens at 180 instead of 192 thus it takes longer for the motor to get to 192. So effectivity your delaying the motor from heating up to quickly. ------------------ 00 GT, K&N, 2 chamber Flowmasters, MAC Tree Killer, Pullies, UPR shifter, Weld Pro Stars, Nitto DR’s,MM#100 13.48@99.27(1.99 60ft) 88 LX coupe X-FHP, 12pt Cage, UPR K-member, 31 spline rear, full spool, more to come

09-21-2000, 11:46 AM	#13
King Snake Registered Member Join Date: Jan 2000 Location: Warner Robins, GA, USA Posts: 210	The 180* thermostat will keep your engine temperature AT 182* and should not allow it to get any warmer than that. The t-stat actually regulates the coolant flow; in other words, it is not either open or closed but can vary the amount of coolant that flows through it. I like the idea of tweaking your IAT. Does its resistance increase or decrease with an increase in temp? And have you tried a pot instead of a resistor? ------------------ '97 Cobra, K&N, 3.73s, Rio Red

09-21-2000, 02:07 PM	#14
Mustang92 Drag Racer! Join Date: Nov 1999 Location: Lake Worth, FL USA Posts: 757	I have an autometer gauge and even with the 180* thermostat it reaches 192* it just takes longer to get there. With a better cooling system it would stay closer to what your saying. Maybe the GT's just have a lower cooling capacity. At least that is what I'm seeing my case. The resistance of the resistor is a fixed temperature and after 3-5 cold starts the EEC will find it and give a MIL. So it's more of a temporary track only item. This is a trick use by alot of people for some time in earlier mustangs, camaro, etc so to be honest I'm not even sure about trying anything else to trick the EEC. There is one guy on the Corral, Casper he sells custom boxes that allows you to adjust which resistor you want and even an auto mode that you leave it in on start up to prevent receiving the MIL. ------------------ 00 GT, K&N, 2 chamber Flowmasters, MAC Tree Killer, Pullies, UPR shifter, Weld Pro Stars, Nitto DR’s,MM#100 13.48@99.27(1.99 60ft) 88 LX coupe X-FHP, 12pt Cage, UPR K-member, 31 spline rear, full spool, more to come