Alright, so I know the setup is pretty horrible for tuning. This is just a toy car at this point, and I am adding to it as I have the chance. Not daily driven, so a lot of stuff doesn't matter.

Stock D16Z6
Stock 240cc injectors
Greddy 15g turbo kit, stock wastegate setting, 5psi
DSM 2g intercooler
2.5" downpipe, 3" full exhaust
Plugs gapped at .035"

I'm running a Crome basemap. 5 psi out of this turbo should be no more than ~160 whp. I'm basically set up to pull 1.25* of timing, and run at close to 100% duty cycle in the upper RPMs in boost. I can post my map if needed.

The car runs great for the first 10-15 minutes it is running. It pulls all the way up to the limiter with no problems - first gear will slip the tires a little bit and bounce the rev limiter at 7500. When the engine is still hot, power drops dramatically at 6500 rpms or so. In first gear, the tires will break a little, but the revs won't shoot past 7k or so.

Here's the problems... I don't have a wideband on it and don't have a boost gauge either. Judging by the solid spool / pull / blow off, I'm pretty sure the turbo is still making 5psi of boost. I also am not set up to datalog.

There's no audible detonation. VTEC is still engaging, so I think that's out as a problem.

So my ideas are...

Injectors have a problem with longer duty cycles as they get hotter?
Engine heat soaked?
Too much fuel, plugs getting fouled?

I'm just at a loss to explain why it runs fantastic at first, then drops off. It's fairly predictable and repeatable.

And yes, I know I need bigger injectors and a wideband. Other ideas are welcome. :D

 

Any chance it's fuel pump failing at high demand when hot? Car is 15 years old...

 

could be ur spark plugs and wires thats what it was in mine. is it a misfire?