I'd try 0.035".

 

Ok

 

Oh boy... old thread, sort of old question but probably pointless as by the time I get an answer, I'll have already figured it out on my own Lol. So... spark plug gap for an Lnf somewhere between 525-600whp... I believe I set them at 0.030 when I completed the build but experienced blowout as well as a lack of fuel above 4200 rpm. Upgraded hpfp and hi energy coils installed now, just 2 days ago... still spark blowout but seems that fuel pressure is good although haven't had a chance to go WoT yet and see. I'm thinking 0.027-0.028 but maybe 0.025 is a better place to start? A smaller gap without blowout is potentially better than still having the issue although if it persists, I'd still have to go lower; I can't see that being possible though but who knows. Anyways, I'm sure there have got to be some guys in here somewhere running lots of power, boost and lb/min to be able to answer this question in the general ball park range. Sidenote, car is super strong (My 13 second TT Fusion feels like a lead slug after driving her at just part throttle the other day) and I'm dying to unleash all that power hahaha. Waited over a year for those 2 pieces of the puzzle to complete it!

Thanks in advance!