Thanks, so no further spark plugs upgrade is necessary on my MY17, or should I just replace them into new just for peace of mind?

 

A VelocityAP stage 2 F-Type should get new OEM plugs installed much more frequently than the OEM interval. 2017 MY and on can just install OEM plugs and go play.

 

Thanks, what is the recommended interval for stage 2?

 

I think it depends on the fuel quality, driving style and more. Because I drive 10K miles over 4 years time and I drive pretty hard when I do take the cars out. I’m changing mine soon. I certainly won’t do more than 15K miles per set. That’s just me. I also change my oil every 2500 miles… no track driving in those miles.

 

You have the right plug type/version with the OEM Heat Range 7 NGK Irirdium, so they will be fine. If you have some miles on the car, you may just want to change them to have a fresh set. Additionally, the OEM GAP in the plugs is typically larger, and you could also benefit from gapping the new plugs between .028 - .032, or re-gapping your existing plugs down to that range. I have mine at .030 (new plugs) and it has been running great. I am sure anywhere in the range would work fine.

DC

 

.028 - .032 gap : how does this translate to [mm]?

 

Multiply inches by 25.4.
0.7112- 0.8128 MM

 

How did that go for you? im thinking of doing the same plug setup of ILKAR7C10 with 0.03 gaping

 

Running great. No issues at all...And no sputtering/misfires at mid-range WOT (Usually where the plugs will misbehave). All good so far.

DC

 

Very interesting point that VAP brought up that no one has ever mentioned?
They run different spark plug gaps on their test mule on all 8 cylinders because of timing differences. My question would be how do you determine what gap to use with what cylinder?
I wonder how much of a difference this makes too? HP, TQ, Durability?
.
.
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All great info, I have the stock 2017 plugs, untouched (no gapping) and the car runs great. All I would do with a Stage 2 car is change out the plugs every 20K miles.

 

For clarification... as I rebuild my '11 XFR, I'm adding a larger crank pulley (Mina), and already had the Mina upper pulley and ECUTG tune. I'm rebuilding my SC, so will switch to a GripTech pulley of the same diameter, and might get it retuned. I just installed the NGK ILKAR7C10 (94940) spark plugs with new ignition coils, but I didn't decrease the gap to the "preferred" lower measurement of .028" - .032" (they come pre-gapped from NGK at .039" or 1.0mm). Since you guys have been running yours for a while with the various gaps, is the current thinking that keeping the .039" pre-gap with tuned cars is still OK, or do I need to pull them out (while it's still really easy to do) and decrease the gap? Thanks!

 

ok so let’s talk data. I made one mistake. When i got my spark plugs regapped to 0.03 i also got a tcu tune that increase the redline from 6800rpm to 7400rpm. When i data logged i did notice some timing correction of 3 degrees on two cylinders only past 6800 rpm. I did not have that before tcu tune and regapped plugs. Which of those is the reason no clue. Keep in mind that the logs prior to tcu tune and regapped plugs were taken at 16 degrees celsius and a humidity of 20%. The logs done after regappingband tcu tune were at 37 degrees celsius and a humidity above 75%. So it could really be just temperature causing this minor correction.

 

OK, so... that was really confusing. I feel like you said a lot of stuff that I should probably be able to understand, but can't. Please keep in mind that I have an '11 XFR (RWD), not an F-Type, so I don't have a TCU tune available (of which I'm aware), so plug gap should be independent of any kind of tranny stuff, right? I get the TCU tune, as I have one on my Audi, but it shouldn't make a difference regarding the plug gap, or am I just drunk and tired?

 

Allow me to attempt a translation:
The TCU tune increased the redline (possibly really the rev limit) from 6,800 RPM to 7,400 RPM, and at those higher RPMs the PCM/ECU retarded the timing by an additional 3 degrees on two cylinders (why only two?). This additional retarding of the timing could have been due to the higher RPM (ie the TCU tune) or the re-gapping of the spark plugs or both.
My WAG for "only two cylinders" is after the spark plug regapping those two plugs had been regapped either too little or too much.
On a 2011 XFR you will have the 6 speed box, the ZF 6HP28, and to the best of my knowledge the VAP TCU tune is only available for the 8 speed box such as on the F-Type, the ZF 8HP70. Maybe it would also work on a newer XFR (2013 to 2015) with the 8 speed box, dunno.

 

Thanks for helping to clarify. Based on that info, and the fact that I don't have a TCU tune available for my '11 XFR, it gets me back to my original question... is the current thinking that keeping the .039" factory-set gap on the NGK ILKAR7C10 (94940) plugs is OK for exclusively ECU-tuned (and not TCU) cars like mine, or should I pull them out (while it's still really easy to do) and decrease the gap to ~.030"? Thanks again for the help!

 

I spoke with @Tuning@VelocityAP Chris about this topic. I am running their stage 2 tune (at the moment) with their TCU tune and he suggested to leave the gap at the preset .039. Not sure if running the stage 3 with upper pulley would make a difference, but I trust Chris assessment on my particular car after he reviewed the data logs.

 

Thanks for the info!