NefMoto

Howdy!  ;)
So, I'm ready to buy my new spark plugs and was thinking about Bosch F5DPOR. Now my question is how do you know what size of gap to set?

I'm thinking about 0.028, but is it good for ~1.5bar of boost? More info on this would be appreciated.

Thanks ;)

Are you running stock coil packs or better?



Edit: fwiw, I have chipped b5 and have always ran NGK BKR7E gapped at .028, this is with stock coil packs. Never any problems. $9.00USD a set~ 15,000 miles or until misfires;) 18~19psi/ 1.2bar

Rob, I'm pushing 1.5bar ;) But I have stock coils... Planning to upgrade them in the future if needed... But I'm interested in how to "calculate" what is the propper gap? What factors affect it? I know that most people for remapped vag use .028. How do you know if it's better to make this gap smaller or bigger? What are side effects? And basically what results to expect with upgraded coils?

I am by no means a pro, but I was always under the impression that the bigger the gap you can run the better.  .028" is the smallest gap I have ever ran on any car, but for these cars I think the stock coils cant push much past that without misfiring under high load, or blowing out the spark under high boost.  My exeprience with this was when i was dialing in my car when it was 4cyl.  Under high boost on the BKR plugs It would break up pretty good, reducing the gap helped a bit.  I am sure a better plug would have helped more though.

I have found the above to be true. I've read with coil pack adapters/2.0 coil packs people are running .044, and said to be much better idle. Hopefully some day I will experience this. I know the bigger the gap the better because of more contact with afr mixture, but as marcellus said, with stock coil packs anything past .028 usually tends to blow the spark out. I don't know what better plugs would do, I was under the impression it has more to do with the dwell time and the efficiency of the coil pack itself. I'm not an expert on any of these things though.

I upgraded to the 2.0 coilpacks when I did the swap, so I cant compare between the stock coils and ICM setup VS. the new stuff.  I do know I havent had any of the issues I had when I was 1.8t with spark.  I am not fully utilizing the gap though.  I through my BKR's in at the factory set gap.  I think it was bigger than .028" but definately smaller than .04.  I have four of whats supposed to be "THE" plugs to go with....Bosch FD-blah-blah-blah-blah, I cant remember, sitting in my house that I was going to use a few years ago.  I need to find two more, and toss them in. 

Good info! :)
So basically if I don't experience any misfire under boost I should try bigger gap?

I prefer 0.0236" Gap.

Technically I believe the answer would be yes. I don't know that you will see any "noticeable" gains unless you upgrade the coils. I'm not sure if the type of fuel matters, as I know you run E85, as far as gap goes.

I have read that people who upgrade coils gain better economy. I believe this has to do with with wider gap/more even burn of mixture.

Professor, I'm unaware of advantages, if any, to running a smaller gap?

/rant on

You should ask yourself if you really need a platinum plug.  My guess is you don't.

Platinum is a poor choice for forced induction.  While there are Audi purists that will argue the OE solution was platinum, successfully modifying these cars is about science and not about emotion.  Audi chose platinum plugs for the service interval, not for their performance.

Copper hands down performs better than platinum with forced induction.  Copper plugs run cooler because they are better at transferring heat.  They also generate a hotter spark than platinum.  The caveat?  You have to change them at every oil change.  Big deal.  You should be looking at your plugs regularly anyway.

On copper vs iridium, iridium costs like 5 times more than copper.  You also won't see any benefit to running an iridium plug unless you're blowing out the spark on a copper plug.  Iridium plugs never seem to last as long as they are claimed to last, either.  So unless the cheap copper plugs are not working, don't run iridiums.

Also, unrelated pro tip:  Don't use that garbage Pentosin mineral oil in your power steering.  Flush it and switch to Mobil 1 Synthetic ATF.

/rant off :D

Lower misfires as far as i have noticed.

Interesting. I've had to regap a few here and there because of misfires (and I was rushingto get done), but I don't believe I've ever had to gap that close. Each cars different I suppose. In theory I guess that may prolong the life of the plugs/lower misfires, but in the scheme of things, at least from what I've gathered, wider is always better for more optimal/economic burn.

I have always used copper because that's what was suggested by many and has always worked. Never tried iridium, I'm not that rich. And besides, changing plugs isn't that hard on a 1.8t.....

I ran Irridium in my car a long time ago when it was just chipped and my car HATED them.  Since then, I only run copper.

"Also, unrelated pro tip:  Don't use that garbage Pentosin mineral oil in your power steering.  Flush it and switch to Mobil 1 Synthetic ATF." - Jason

Why? 

In a nutshell, Pentosin quickly loses viscosity with temperature, has poor anti-wear properties, poor seal conditioning, and extremely poor anti-foaming properties leading to pump cavitation.  Oh, and Pentosin is more expensive than Mobil 1 synthetic ATF, despite mineral oil being one of the most abundant products of petroleum distillation.

There are a few things you'll notice when you switch to M1 synthetic ATF:

1) The high pressure bypass doesn't squeal like a pig at full lock in parking lots
2) Steering effort is consistent across the entire temperature range
3) Mobil 1 has extremely effective anti-foaming agents preventing pump cavitation in harsh driving (IE, open track on hot days)
4) If your rack is currently leaking, it will slow or completely stop leaking with Mobil 1 due to the seal conditioning additives.

I've got about 150k on my rack with M1 and no leaks/issues.  I've had the car in sub-zero temps and 125+ degree heat and run more track days than I can count.  I have also never changed the M1.

Of course YMMV, and I am not a doctor :)

Nuff for me.  I was asking because I need to redo my powersteering cooler so I will need to replace the fluid anyhow.  I have noticed the full lock squeal, and inconsistent effort.  I will try it out.