Great advice in this thread/forum
This sums it up here: https://www.evolutionm.net/forums/ev...l#post11876652
Interesting plug gap (discovery / discussion)

Couple things might be of interest for extra reading
Plug gap?
There is some measure of truth, to the tale of wider plug gaps being more conducive to combustion efficiency, mileage, even performance.
However this is only true up until the point that any excess gap causes a misfire. In high boost applications, we gladly exchange a margin of gap for a consistent ignition.
I usually tell people (random engines) to run the widest gap they can manage. But most people aren't using 20+psi of boost when I say that. So I won't mention it here other than the historical reference to the reason why.

Torque/output
In general, whenever diagnose an issue like this, and especially when you have dyno runs to compare with. It is usually good practice to compare torque lines with smoothing:0
The torque of the engine is a measure of cylinder pressure, or effective integral of component pressure anyways.
The shape of the curve, whether smooth or jagged, can have varied meaning. Any oscillation of torque in the curve with smoothing:0 while boost pressure is steady, indicates an issue somewhere with the transfer or production of torque, could be ignition timing related or drivetrain related, etc...

Thank you all, You will all be the first to know when I get my stuff back and tuned again.

Please update I really want to know what was the problem or problems you had because I will be doing a similar build but nothing can go wrong because it will then void my 2 year warranty for my Evo.

damn, all i saw was the comment about the gap and i was uninterested in having that place be a good reference for tuning. My car with an 8 range plug at .029 gap wouldnt make over 15psi, i checked and gapped before i got the car to the tuner and the car was flawless after that. Would like to know what the final outcome was tho

Things have gone from bad to worse.

I fixed my cracked intake manifold, fixed all boost leaks, checked my injectors by FIC (Fine) brand new Spoolinup COP, brand new OEM EVO IX PLUGS gapped to .19, car misses even worse now. It only made 380 WHP and sounds like a 2 step under boost.


I’ve paid for 2 dyno tuning sessions and the car simply won’t run. I’ve had it and I have no clue the issue.

Did it have the spoolin up initially?

Throw stock coils on it, go drive it and see if it is still present.

Edit: Just re-read, Try some stockers.

I also think you should try oem coils. I have a spare set if you are close by.

I have still have my stock setup and It's going back on ASAP.

Also, I know you just built it. But have you checked timing and compression just to rule those out?

Was it knocking on the last dyno?

If it's knocking from an outside source, like the exhaust hitting or piston slap. Not detonation. It could be the timing getting pulled from the knock that's causing the "missing".

At 6 degrees, if it pulls more than a couple I'm sure it would drive like dog ****.

Do you happen to have any logs to see what's going on.

No logs sorry. It started to do this prior to my engine build.

Gapped to .19, or .019"?

Sorry, .019, they came that way out of the box.

how is the engine/head to chassis grounding?

Stock + DIY Ground kit. Voltage was very stable after that.

When the motor was built, was actual compression verified? IE, you mostly need to check piston deck height and then calc your actual compression based on bore size, head CC, and piston dome/dish CC.

Have you attempted to verify base timing?

Is the car on MAF or speed density? If on speed density, have your tried replacing the MAP sensor?