I've got a coworker that has a '02 truck with the 4.8 liter engine. He bought a sneaky pete NOS kit yesterday for dirt cheap. We were thinking about putting the kit on it, but he wants to make sure that the tuning is rich enough from the factory, because it is a dry kit. Has anyone dyno'd their 4.8L truck with the factory programming? How rich was the factory tuning? How much timing does it have at WOT with the factory tuning?
TIA,
Kevin Winstead

 

Typically, the tuning from the factory is rich. If he has done any other mods like intake, headers,GMAF, exhaust, hypertech, etc... it may have leaned it out some. There are several guys running dry nirtous kits with no problem on these motors. Do go too extreme with the shot or your injectors won;t keep up. I think a 100 shot is safe for fuel, other run even larger.

Timing is low from the factory, and fuel is rich. No problem. If he has hypertechs "power tuning" installed, that will raise timing and lower some areas of wide open fuel. Thats why you shouldn't run hypertechs tuning and nitrous at the same time. The hypertech settings for shifting, rpm limiter, etc... are fine with nitrous.

 

With a dry kit, shouldn't you spray directly into the maf sensor?

 

Yes, before the MAF.

 

Spray at least 6" in front of the MAF so it will get a better pattern.

 

I agree with what Bigtex said about taking out the HPPIII setting on a dry shot system. I think that was a contributing factor in my "piston failure" <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" />

Greg

 

i was running a 4.8 with 8-10# and still had to lean it out a bit and still was a little rich. wouldn't worry too much about it, put it on a monitor sometime soon or at least do regular plug readings.

 

Thanks for the help guys!
Kevin