Ford Focus ST Forum banner
1 - 18 of 18 Posts

·
ST Nation First Sergeant
Joined
·
315 Posts
Discussion Starter · #1 ·
So, with the big turbos coming out, spark plug upgrades will be following very closely. When increasing the power by that much it is important to move to a slightly colder plug in order to keep cylinder temps down and reduce chances for pre-ignition/detonation.

The factory spark plug for the focus ST is an NGK plug PN: LTR6DI-8. If you break down the part number this is what you get.

LT (Long thread reach plug Tapered seat type 25mm) R (Resistor) 6 (heat range) D (Metal Shell Plating Spec Change) I (Laser Iridium) - 8 (0.8mm or .032")

The heat range for NGK plugs goes from 2 to 11 with 2 being the hottest and 11 being the coldest. This means that there are a couple options to go with for a colder spark plug.

The first is the NGK LRT7IX-11. This plug comes with a gap of 1.1mm or .044" and will require you to regap them to a range of .030" - .032". The IX at the end of the part number stands for High Performance Iridium.

The second option is the Denso ITV22.

I stands for iridium, and the letter T is the Thread Diameter x Hex size (14x16.0). The letter V represents the thread reach of 25mm with tapered seat. The heat range is designated by the number 22. This is equivalent to the NGK 7 and therefore one step colder than stock. The number 20 corresponds to the stock heat range or NGK 6.

We are going to be running the NGK LTR7IX-11's in our car with the GTX2867. We are not sure what gap we are going to run yet but will be experimenting with that a bit to see what works best.
 

·
Registered
Joined
·
90 Posts
gap. i know with some of the mazdas ive done and my mitz. spark plug gap at .030 seems to work good on the turbo cars. None have been full out race builds most 350-400 hp. street/ strip cars.
 

·
Registered
Joined
·
1,533 Posts
Thanks Edge, that was a nice explanation of the spark plug options.
 

·
Registered
Joined
·
360 Posts
So, with the big turbos coming out, spark plug upgrades will be following very closely. When increasing the power by that much it is important to move to a slightly colder plug in order to keep cylinder temps down and reduce chances for pre-ignition/detonation.

The factory spark plug for the focus ST is an NGK plug PN: LTR6DI-8. If you break down the part number this is what you get.

LT (Long thread reach plug Tapered seat type 25mm) R (Resistor) 6 (heat range) D (Metal Shell Plating Spec Change) I (Laser Iridium) - 8 (0.8mm or .032")

The heat range for NGK plugs goes from 2 to 11 with 2 being the hottest and 11 being the coldest. This means that there are a couple options to go with for a colder spark plug.

The first is the NGK LRT7IX-11. This plug comes with a gap of 1.1mm or .044" and will require you to regap them to a range of .030" - .032". The IX at the end of the part number stands for High Performance Iridium.

The second option is the Denso ITV22.

I stands for iridium, and the letter T is the Thread Diameter x Hex size (14x16.0). The letter V represents the thread reach of 25mm with tapered seat. The heat range is designated by the number 22. This is equivalent to the NGK 7 and therefore one step colder than stock. The number 20 corresponds to the stock heat range or NGK 6.

We are going to be running the NGK LTR7IX-11's in our car with the GTX2867. We are not sure what gap we are going to run yet but will be experimenting with that a bit to see what works best.
This is interesting, but off from what others were speculating on simialr threads. I saw where Ford Racing is now offering a package with the ITV24, which according to your explanation is two steps colder than stock. I also saw in the owners manual where a different number is used for the plug, CYFS12Y2. Perhaps this is just a Ford number for the same NGK plug. It seems there is a lot of contradictory info swirling around. It will be nice when all the dust settles on this issue.

Wes
 

·
ST Nation First Sergeant
Joined
·
315 Posts
Discussion Starter · #5 ·
This is interesting, but off from what others were speculating on simialr threads. I saw where Ford Racing is now offering a package with the ITV24, which according to your explanation is two steps colder than stock. I also saw in the owners manual where a different number is used for the plug, CYFS12Y2. Perhaps this is just a Ford number for the same NGK plug. It seems there is a lot of contradictory info swirling around. It will be nice when all the dust settles on this issue.

Wes
That is true, there is some contradictory info right now. The CYFS12Y2 number is the ford part number I believe and is also on the plug we pulled out of the car. I think where the confusion comes from is that according to the cross reference, the Ford recommended Motorcraft SP-527 will pull up a denso ITV22 advertised on ebay. I trust that the ITV22 fits the ST but it is not the same heat range as factory. And the ITV24 advertisement was at a SEMA display and I don't think the ITV24's actually come with the Ford Racing tune up package. The Denso ITV22's have been and still are on a huge backorder and they are very hard to come by so we suspect that the Ford Racing guys at SEMA just completed the display with what was available. I will find out for sure though before we say anything that is set in stone.
 

·
Registered
Joined
·
23 Posts
Man, thats a lot of infor for just spark plugs. thanks for the post guys, this is really going to help out when I decide to change them out. On a fairly stock vehicle, would changing to a colder heat range do anything performance wise? I ask cause I'm doing the standard bolt on things now, e.g. intake, exhause, blow-off valve ext. I also have a tunner coming in and want to know if better plugs will help or hinder the build
 

·
ST Nation First Sergeant
Joined
·
315 Posts
Discussion Starter · #7 ·
Man, thats a lot of infor for just spark plugs. thanks for the post guys, this is really going to help out when I decide to change them out. On a fairly stock vehicle, would changing to a colder heat range do anything performance wise? I ask cause I'm doing the standard bolt on things now, e.g. intake, exhause, blow-off valve ext. I also have a tunner coming in and want to know if better plugs will help or hinder the build
A colder plug is only really necessary when running significantly higher boost or a larger turbo. More boost/more air = higher cylinder temps and the purpose of the colder plug is to bring the temps back down to reduce chances for preignition and detonation. They won't benefit and could possibly actually hurt you on stock or close to stock boost levels/cylinder temps.
 

·
Registered
Joined
·
23 Posts
Thanks for the info. Guess I'll keep the bolt on's for the length of the warranty. Are there any plugs that are better than stock but still in the same heat range, you know, a more powerfull spark for efficiency?
 

·
ST Nation First Sergeant
Joined
·
315 Posts
Discussion Starter · #9 ·
Thanks for the info. Guess I'll keep the bolt on's for the length of the warranty. Are there any plugs that are better than stock but still in the same heat range, you know, a more powerfull spark for efficiency?
The stock plugs are actually very good plugs. They are made by NGK and are Laser Iridium. It doesn't get much better than that.
 

·
Registered
Joined
·
90 Posts
In my experience with stock and tuned Saab turbo motors, the ONLY plug that works in those engines is the Factory NGK. On the older ones before Trionic engine management came along, you could get by on champions or autolites, but performance (mainly through a drop in fuel economy) was reduced.
All Trionic (T5, T7, T8) cars NEED factory plugs, just to function. Saab's T5 and T7, for example, uses the Ignition coil (DIC) to monitor TDC and engine chamber pressures (Knock) through the spark plug. If the internal resistance is off form the specification, or non-NGK plugs with different gaps or construction is used, the change in voltage through the plug is great enough to damage the DIC, a $400 part. Doesn't matter if the car is a 250k mile, 180hp granny car, or a 8000 rpm, 500hp fresh race engine.

How does this translate into Ford's latest Ecoboost? I believe that OEM plugs will do just fine, from stock 250, all the way up to 500+ (guessing here.)
When the engineers designed the direct injection and ignition control systems, EVERYTHING was taken into consideration, likely including plug gap, internal resistance, heat range, flame front and lifetime.
Would it be wise to yank out a perfectly good set of plugs for Autozones Next Best Thing? No.
Until the factory plugs wear out, and/or someone manages to make enough power that the plugs become a limiting factor, I'd say save your money and run stock.
 

·
Registered
Joined
·
360 Posts
In my experience with stock and tuned Saab turbo motors, the ONLY plug that works in those engines is the Factory NGK. On the older ones before Trionic engine management came along, you could get by on champions or autolites, but performance (mainly through a drop in fuel economy) was reduced.
All Trionic (T5, T7, T8) cars NEED factory plugs, just to function. Saab's T5 and T7, for example, uses the Ignition coil (DIC) to monitor TDC and engine chamber pressures (Knock) through the spark plug. If the internal resistance is off form the specification, or non-NGK plugs with different gaps or construction is used, the change in voltage through the plug is great enough to damage the DIC, a $400 part. Doesn't matter if the car is a 250k mile, 180hp granny car, or a 8000 rpm, 500hp fresh race engine.

How does this translate into Ford's latest Ecoboost? I believe that OEM plugs will do just fine, from stock 250, all the way up to 500+ (guessing here.)
When the engineers designed the direct injection and ignition control systems, EVERYTHING was taken into consideration, likely including plug gap, internal resistance, heat range, flame front and lifetime.
Would it be wise to yank out a perfectly good set of plugs for Autozones Next Best Thing? No.
Until the factory plugs wear out, and/or someone manages to make enough power that the plugs become a limiting factor, I'd say save your money and run stock.
Then why does Ford Racing change them out?

Wes
 

·
Registered
Joined
·
90 Posts
Then why does Ford Racing change them out?

Wes
Who knows... Ask em!

I guess in their testing maybe lowering the heat range got rid of some knock or quelled a hotspot, BUT THATS MY GUESS...
I dont see why changing the plugs is necessary with the high resolution of knock sensors and individual ignition control, along with the direct injection.
 

·
Registered
Joined
·
1 Posts
Hey everyone, I have a question. I'm running a stage 1 91 oct tune on my 17 ST and I'm getting different opinions on whether or not I need to run colder plugs or I can just run stock. The only aftermarket thing I have is an RS intake box. Thank you in advance!
 
1 - 18 of 18 Posts
Top