Colder spark plugs, really? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Robert986 · 03-20-2021, 08:17 AM

So, as I guess I have written about before I have done a lot of "breathing mods" om my 986s 2003.

Input: Cayman Airbox + the Larger MAF, a well flowing hose, 74mm TB, IPD Plenum.
Output: Catless Headers, catless "testpipes", FVD Sound version muffler.

I´m working with a well reputated tuner with Dyno and long experience. Since the larger MAF tube needs to be adressed somehow we decided to start with the 550 anniversary tune (since that car utilizes the larger MAF tube) and proceed with the mapping from there.
So far so good, but now before we start the mapping my tuner advice me to prepare the car with spark plugs, "one notch" colder than standard to make room to max out the tune in the high register. This makes me a bit hesitant, I thought that going to a colder plug might be reasonable for a turbo charged engine or something with a lot more than intake/exhaust mods.
I´m now running the BERU 14FGR6KQU as the Porsche recommended standard.
May I ask you guys for any thoughts? My suggestion would be to start out with the standard plug and then follow up how it behaves. The car is 80% street but when on the track it´s driven hard...
I may add that the tuner is very well reputated and experienced, but I guess mainly from a lot more extreme cars than the M96 Boxster.

Robert986 · 03-20-2021, 08:43 AM

One other really cool finding however is that now when I go catless, the previous drone is gone. OEM-cats: no drone, 200cel cats: quite a bit of drone. I have no idéa why.. Will report back after the car is properly mapped so I can really try it.

Robert986 · 03-20-2021, 10:59 AM

I think I'll go with "one colder" but which one would that be? I guess 14FGR6KQU is a grade 6, so I want a grade 5, but cannot find anything called 14FGR5KQU

edc · 03-20-2021, 03:31 PM

I used the Denso iridium when mine was mapped.

ike84 · 03-21-2021, 04:35 AM

Robert, I'm not sure you are going to need colder plugs. Obviously your tuner will know better, but you haven't done anything that will change the cylinder temps (FI, nitrous, increasing comp) and I can't imagine he plans on advancing ting that much if any with the increased flow. FWIW, double check beru's temp grading system - different brands move in different directions with the numbering.

Will you do us a favor and ask your tech the reasoning behind the colder plugs? Maybe he knows something we don't.

Sent from my POCOPHONE F1 using Tapatalk

Robert986 · 03-23-2021, 06:03 AM

Quote:

Originally Posted by edc

I used the Denso iridium when mine was mapped.

Thanks, my Tuner now adviced me to use them, Denso IK24 so I ordered a set of those!

Robert986 · 03-23-2021, 06:05 AM

Quote:

Originally Posted by ike84

Robert, I'm not sure you are going to need colder plugs. Obviously your tuner will know better, but you haven't done anything that will change the cylinder temps (FI, nitrous, increasing comp) and I can't imagine he plans on advancing ting that much if any with the increased flow. FWIW, double check beru's temp grading system - different brands move in different directions with the numbering.

Will you do us a favor and ask your tech the reasoning behind the colder plugs? Maybe he knows something we don't.

Sent from my POCOPHONE F1 using Tapatalk

Thanks, good reflections.. I´ll go for the Denso IK24, will ask later about the logic behind colder plugs.