Center section of manifold cracking..

[marek4792]

So another update went back to the stock 505HP file Rawze sent me, power was very comparable and mpg went up at least 1/2 mile a gallon and 100 degrees cooler EGT wise, did the cylinder cutout test and #5 when cut out would tick tick tick then stop and then come back intermittently. Took the cracked aftermarket manifold off, fired it up and idled fine, but as soon as I snapped the throttle #5 was dumping fuel out, replaced said injector and tube and put the OEM manifold back on it with a new center section because it would crack on the turbo flange sealing surface, aftermarket would crack on the corners where it met 3 and 4 above the turbo flange. Idles smoother and seems to run and sound better and more responsive, but I know the other 5 injectors aren't far behind. No white smoke when snapping the throttle so far..

My conclusion, injector was leaking between pulses creating uneven heat in close proximity to the turbo flange, and the fact the tune was a 565hp in a Volvo despite being OEM correct (just not for this truck in particular, this truck maxes out at 525hp from factory) besides some alterations by RR (no fault of him) creating the ripe conditions for cracking it. I know Haggai ran into an issue of injectors leaking like this and still pass a leak-down test and made a tool to spot ones that do this.. I'm really hoping this was my case and is the end of the cracking manifold saga..