Ok guys, so i dont really post on here, but i am just truly amazed and scared at the same time. I drive a NNBS 4.8 WT w/76mm Turbo. Tune isnt quite right yet, im at 11psi, running 92 oct gas, no meth.

Stock pump & 2ndary walbro on hobbs (4psi)

Last night racing a friend, on the 2nd race, walbro or hobbs stopped working in 2nd gear. maybe around 4k rpm at WOT, i suddenly saw my wideband spike up to 17.6 ! i immediatly let off and almost crapped on my pants. I dont know if i should be scared or amazed, cause absolutely NOTHING happened to the truck.
I know my timing is waay low cause i havent installed my ARPs & LS9s, but 17.6! holy mother of god!

 

O yeah, iv run mine on 14psi 180iats with no problem, had a waist gate problem one and hit 20psi at 13.5 af once aswell, you tune it to pull timing when something like that happens u will never hurt it.

 

Actually going that lean isnt that bad...its when it runs at stoich that you break ****.

 

Really? didnt know that.. why is it?

 

Because the maximum combustion temperature happens at stoich and falls off to either side, for different reasons, but its still not as hot as stoich.

like this

 

Yeah 13.0-13.5 af is the worst spot to be, that will make a mother load of power and knock at the same time

 

Or whats worse is when you hit 3rd gear and it starts sputtering.. Scan showed 195kpa in second and 198kPa in 3rd.. didnt even think about the 2bar map stopping at 198kpa........
last pass at the track i just so happened to look up at my boost gauge and saw it at 25psi and still climbing
so i let off the ole go fast pedal and went straight to the pits to hook up to the trailer........

 

Lol I bet! I have a 3 bar and have it drop to no timing and max fuel if I hit 21+ psi, atleast it will miss out and ill notice it, there's to much going on at these power levels to be able to watch all the gauges.

 

I ended up adding timing and leaning it out to the 11s before i even looked up at the guage...

 

Chuck Norris is more likely.