Spark plug install question...
Thread Starter
3rd Gear Member
Joined: Aug 2011
Posts: 814
From: Nebraska
Spark plug install question...
Ok, This weekend I will be replacing my injectors, and figured while im there may as well replace the spark plugs and check the COP boots. My question is is it wise to use some antiseize on the new plugs on this motor? I usually use it but I wanna make sure itll be ok on this motor.. Got my torque wrench handy and ready to go. Also...is the correct gap around .052 or so for a stock engine?
3rd Gear Member
Joined: Nov 2009
Posts: 589
From: AZ
I dont remember what I gapped mine at, whatever FORD reccomends until your running boost or spray everyone says to run them at .035 but your .052 for NA doesnt sound far off, I remember thinking it was pretty high. I used Anti-Sieze and have had no problems.
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
This is from our "discussion", Steve had asked about my using the FRPP 24 lb/h injectors. Make note that they absolutely 110% DO require re-tuning to have the low and high injector slopes, break-point and minimum pulse width set to the new injector's recommended values (see chart below).
Also,
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This is the calibration summary from FRPP, it is only the fur values in the upper left that are required to be changed on an EECV tune. FWIW on my '03 GT I settled in on a high slope value of 25.58 lb/h as it was running rich at WOT with the suggested 24.30 lb/h value.
The stock 19 lb/h injectors (orange) on the '99 through '02 GTs are barely adequate to supply the stock engine, approaching 90% duty cycle at WOT and revs over 5000 rpm. They are the same injectors used on the non-PI engines ('96-'98) and should have been upgraded in '99 for use in the PI engine.
After the the '99 Cobra horsepower debacle Ford began a review of the HP claims for all their line, and in the very last of the 2002 MY, and in '03 and '04, installed 21 lb/h (lavender) injectors in the GT. These provided better support for the 4.6L 2V's claimed 260 fwHP, operating at a more sensible 80% duty cycle when flat out.
However with even modest hardware modifications (intake and exhaust), and re-tuning to take advantage of such mods (which pump up mid-range power mostly, but also let the engine pull strongly right up to the rev-limiter), the 21 lb/h injectors once again get up into a 90%+ duty cycle.
With my mods and tune I dyno'd at 252/295 rwHP/torque with the 21 lb/h injectors, and 262/305 re-tuned using the 24 lb/h units.
So there you have it, keeping the injector duty cycle under 80% allows more precise fuel control...
After the the '99 Cobra horsepower debacle Ford began a review of the HP claims for all their line, and in the very last of the 2002 MY, and in '03 and '04, installed 21 lb/h (lavender) injectors in the GT. These provided better support for the 4.6L 2V's claimed 260 fwHP, operating at a more sensible 80% duty cycle when flat out.
However with even modest hardware modifications (intake and exhaust), and re-tuning to take advantage of such mods (which pump up mid-range power mostly, but also let the engine pull strongly right up to the rev-limiter), the 21 lb/h injectors once again get up into a 90%+ duty cycle.
With my mods and tune I dyno'd at 252/295 rwHP/torque with the 21 lb/h injectors, and 262/305 re-tuned using the 24 lb/h units.
So there you have it, keeping the injector duty cycle under 80% allows more precise fuel control...
If you wish to get a set of the FRPP 24 lb/h injectors then do it in the near future as they were discontinued by FRPP 1-1/2 years or so ago. They can still be found from a few vendors--Google FRPP m-9593-aa302. Brothers Performance says they have them for $170, but their availability is drying up rapidly.
The MSRP was $250, most suggested replacements are in that range...
The MSRP was $250, most suggested replacements are in that range...
This is the calibration summary from FRPP, it is only the fur values in the upper left that are required to be changed on an EECV tune. FWIW on my '03 GT I settled in on a high slope value of 25.58 lb/h as it was running rich at WOT with the suggested 24.30 lb/h value.
TECH SAVANT
Joined: Dec 2006
Posts: 10,937
From: Saint Augustine, FL
FWIW, in the factory shop manuals Ford makes no mention of using any compound of any sort on the plug threads--however under scheduled maintenance they would only be changed twice¹, every 100k miles, over the entire life of the vehicle.
That said I use never-seize, having changed/pulled-replaced the plugs at least a dozen times since owning the car...
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¹ - Once at 100k and again at 200k, then maybe again at 300k?
That said I use never-seize, having changed/pulled-replaced the plugs at least a dozen times since owning the car...
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¹ - Once at 100k and again at 200k, then maybe again at 300k?