1fitty

I just put them in as they come....never been a problem.

mike243

You might want to ask around before spending $ on a CAI ,would be better spent on a tuner from what I read

NASSTY

I always check the gaps first, before installing. I've installed a few sets of SP534s in my 2011 and 2014 and they were always pre-gapped @ .030
When I was running a tune I tightened the gaps down to .028

In the owners manual of my 2017 it says to use SP534's, but the dealers are now saying to use SP550's. I picked up a set of 550's and they are pre-gapped @ .028

beaker80

Rock Auto is showing the Motorcraft SP550 for the 2017 3.5 turbo for 4.88 CDN. For my 2011 3.5 Eco they show the Motorcraft SP534 (Iridium) for 8.41 CDN. I have these installed but due for a change. I can't find any info if the SP550 is iridium. Are they a copper core? Big price difference when you add in shipping to Canada. I might check local auto parts stores to see how much they are here in Canada.

NASSTY

The 550's are iridium. I got them from Tasca. https://www.tascaparts.com/oem-parts...ark-plug-sp550

beaker80

I ordered and received a set of 6 SP-550's from Rockauto. Total with shipping, exchange rate, vendor discount and taxes was 36.17 CDN. On the side of the box it says "Spark plug gap is not adjustable." I checked them(0.028"). I found that statement funny.

5.0nly

Will the SP-550s work on a '13 Eco?

beaker80

They should work in 11-18 Eco's as they are a replacement for the SP-534 plug. It will be awhile before I install mine. They are the only plug listed for the 2018 on Rockauto.

frakchered

Good to know. I couldn't find much info on the SP-550's. I was debating buying them since they are gapped at .028. Luckily I found the SP-534 for 35.46 shipped so I will trying the 550's next time.

frakchered

So, I just changed my factory plugs out at 71,500 miles. I didn't have one issue what so ever. I took the SP-534's I bought checked the gap which were either .032 or .033 on the plugs I received. I regapped them all to .028.


Once I started the process I checked gap on all the ones I pulled:
R1 .041 L1 .042
R2 .039 L2 .039
R3 .041 L3 .040


So I should see a notable difference in idle and running. Maybe a little better performance and MPG I am not sure.