So, my exhaust from catalytic converter to muffler was rusted out & needed to be replaced. The car ran fine, just sounded horrible. While I had it in the shop I replaced the full exhaust (3" Megan Racing down/mid pipes & JIC Spartan DE exhaust) & put in a PFC programmed by one of the site vendors. I went through the before starting/idle correction steps & it seemed to be running fine so I took it out. During acceleration, it runs great until about 5500 rpms then the power drops off. Luckily my brother was out driving w/ me & he told me there were flames shooting out the exhaust. So we coordinated it & he watched closer while I drove. The flames are about 1.5 ft out the exhaust & only come out during the power loss during acceleration in the rpms of 5500 to redline. Anyone know what's going on?

A local guy that is with SCCA said I was maxing out my fuel injectors, so I watched them on the commander, they never go over 60% so I don't think that's it.

 

List all of the modifications you have on the car. 60% peak injector duty cycle is what a completely stock FD would reach.

You should be well above 85% peak injector duty cycle. On the PFC, you can hit the up arrow on the meter output screen to switch to the "black box" display mode, which will record peak values achieved during the driving trip in the black box next to the real-time outputs. Go drive around w/ the black box display enabled and then see what it records. What is your peak boost pressure? Is your secondary turbine coming online?

For example, I have HKS RS Reloaded intakes, HKS downpipe, Knightsport High Flow Cat, HKS Hiper exhaust, Trust SMIC w/ compression tube, Efini Y-pipe, and PFC w/ late-version basemap and I typically observe low 90% range peak injector duty cycles @ ~12 PSI.

I wonder if you're hitting some sort of fuel/boost cut because of possible boost pressure spikes... tell us more info

 

Are you saying that you do not have any idea what would cause flames to come out of the exhaust?

Too much fuel or the ignition is failing and the unburnt fuel is burning while traveling through the hot exhaust pipes.

Take it back to your mechanic to diagnose.

 

Mods: HKS super mega flow intake, 3" Megan Racing down/mid pipes, JIC spartan de exhaust, Apex'i pfc w/ commander.

I'll do the "black box" tomorrow & relay it.
Unfortunately I don't have a boost gauge.

I know what causes the flames, I was wondering how the excess fuel is getting there. Ignition & other parts worked fine before the mods.