Lord I hope someone here can help...

I have a 2000 GT with a rebuilt 4.6 with a vortech blower.

A new mechanic was just looking at it and was upset by my sparkplugs. Said I had .020 gap copper plugs, and that I should have .056 gap platinums. I called Vortech and they said .035 copper. Anyone have ANY idea which is the right one?

This is killing me

Thanks!

 

for a power adder application- s/c and especially nitrous you want to avoid detonation at all costs- one great way to do this is by using a colder (heat range) plug. Platinum is a bad idea IMO- I would use NGK TR6s. They work great and are 1.99 a piece. Also set gap between .030 and .035. Hope that helps!

 

Mechanic is looking at factory spec, not the modded spec.

Frequent thing that mechanics overlook is a Modified car. I.E. factory spec on the car tires is 32PSi, however that is on a tire that is rated at 35PSI max or stock. I have low profile BFG KDW tires that are rated at 44PSI Max so I run them between 35-38 PSI. Tech tried to tell me I should run at 32PSI as stated in the owners manual. I told him that's great for a STOCK tire and asked if he would replace a $155 if it blew on account of his error. That ended the convo.

 

Agree^^^ Although I use autolites in mine. .030 gap, 2 heat ranges colder.

 

Yep. .030 colder plug. I would trust Vortech over the mechanic anyway. They designed the system and know the best combo for it to work properly.

 

it really depends on how much boost and power you're making... this should be a sticky and the info was borrowed

Spark Plug FAQ

Stock Heads also (Dart Windsor Jr & Sr)

Naturally Aspirated (non-projected tip)
NGK
Specifications:

Thread Size= 14mm
Hex Size= .625
Reach= .46
Seat Type= Tapered
Electrode= V-Power

NGK R5673-6 Stock Number 2405 (1 heat range hotter)
NGK R5673-7 Stock Number 2817 (Factory heat range)

Naturally Aspirated (non-projected tip)

Specifications:


Thread Size= 14mm
Hex Size= .625
Reach= .46
Seat Type= Tapered
Electrode= V-Power

NGK R5673-6 Stock Number 2405 (1 heat range hotter)
NGK R5673-7 Stock Number 2817 (Factory heat range)

Autolite Stock Heads

Autolite 25 Naturally Aspirated
Autolite 24 1 Heat Range Colder
Autolite 23 2 Heat Ranges Colder

Autolite Race Series for Stock Heads

Autolite AR135 Naturally Aspirated Only
Autolite AR134 1 Heat Range Colder
Autolite AR133 2 Heat Ranges Colder


NGK Forced Induction

NGK-Non Projected Electrode
Specifications:

Thread Size= 14mm
Hex Size= .625
Reach= .75
Seat Type=
Electrode= V-Power

R5673-8 Stock Number 3249
R5673–9 Stock Number 3442 for tons of boost and power.

Aftermarket aluminum heads (TFS, Edelbrock, AFR, Canfield, Brodix)

NGK Forced Induction

R5671-A8 Stock Number 4554, 1 heat range Colder (up to about 600rwhp)
R5671–A9 Stock Number 5238, for 18+psi, 2 heat ranges colder 650+ rwhp
R5671–A10 Stock Number 5820, for race cars.

Autolite Forced Induction and N/A

Autolite 3924's Naturally Aspirated Only
Autolite 3923’s 1 Heat Range Colder, good for approx 550rwhp
Autolite 3922’s 2 Heat Ranges Colder, good for approx 650rwhp

Autolie Race Series for aftermarket heads

Autolite AR3935 Naturally Aspirated Only
Autolite AR3934 1 Heat Range Colder
Autolite AR3933 2 Heat Ranges Colder

Plug Specs for GT-40 Iron, GT-40 Aluminum, GT-40X, & GT-40P Heads

Thread Size- 14mm
Hex Size- .625
Reach- .708
Seat type- Tapered
Electrode- Standard Nickel
Projected Tip

The stock equivalent replacement part numbers according to the Motorsport Catalog are:

Ford MotorSport Part Number AGSF-32C for the GT-40 Aluminum, and GT-40X
Ford MotorSport Part Number AWSF-32C for the GT-40P, and GT-40 Iron

These plugs cross to:

NGK - BPR6EFS Stock Number- 3623 (Stock Heat Range)

Autolite- 104

These are the NGK Race Series Part numbers and specs:

Thread Size- 14mm
Hex Size- .625
Reach- .708
Seat type- Tapered
Electrode- V-Power
Non-Projected Tip

NGK- R5724-8 Stock Number- 7317 (1 Heat Range Colder)
NGK- R5724-9 Stock Number- 7891 (2 Heat Ranges Colder)
NGK- R5724-10 Stock Number- 7993 (3 Heat Ranges Colder)

 

and you gap should be around .030

 

Yes I agree, a couple steps colder on the heat range plus a copper style plug and a .030 gap. Moat platinum plugs have a fine or small tang on the electrode. In a power adder car, these can run hot and create preignition and cause engine damage. You also tighten the gap up to help prevent the boost from nullifying the spark which happens on a wider gap.

 

Wooo that post was a mouthfull; I have to admit, I didnt quite get it!

Is there an exact sparkplug I should be looking at? Its a 4.6 with vortech s trim, making like 11 or so psi, aftermarket heads... well heck, the info is in my signature I guess Any ideas?

Thanks!

 

The development of precious metal high temperature electrodes (using metals such as yttrium, iridium, platinum, tungsten, or palladium, as well as the relatively prosaic silver or gold) allows the use of a smaller center wire, which has sharper edges but will not melt or corrode away. The smaller electrode also absorbs less heat from the spark and initial flame energy