LS Build: In Progress

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06-30-2022, 12:41 PM

#531

mtnrider

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any progress with this build

07-01-2022, 06:43 AM

#532

articfriends

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Quote:

Originally Posted by mggdoors

Do yourself a favor and pull the intercoolers and gusset them. Also run the zl1 lid if possible. Good for 20 or so hp and intercooler is more efficient. Port them as well. I did mine. Pay close attention to the area right above the gasket area that mates to head. Youll notice square edges. Round those out and open them up. Injectors I would decap the zl1 injectors and have them cleaned and flow matched. Good for 105lb/hr. And cheap. Last but not least a nice little trick if you dyno them and your ecu has capability is to fire injectors the second the intake valve opens or 0-5 degrees before and stop them at or before the valve closes. Easy BIG hp gain and does let fuel pool behind calve/cleaner afr etc. I actually showed my dyno guy this and he couldnt believe the gains. Over 40hp in my case. If you have overlap and can get enough fuel in within the valve event I suggest injecting after the overlap event. But only if you can get adequate fuel in by the time it closes.

Where did you see the '40 hp" gain from timing a port injected injector rpm wise? Im skeptical as I own a dyno and high end injector machine and have never found a single hp gain form sequential or timed injectors in a port vs batch fire OR a difference in AFRS whatsoever off of idle. Heres the reason WHY I disagree with the 40 hp gain: at say 6000 rpm, the intake valve is opening and closing 3000 times a minute. The injector is also firing 3000 times a minute. at a typical top end MS of say 13 MS, the injectors firing for .013 seconds (keeping deadband out of discussion which is minor) , extrapolating the data out to 3000 times minute, .013 x 3000+ 39, thats 39 seconds, so of in a minute of valve opening and closing 3000 times, the injector has sprayed fuel pretty much steady for 39 of those 60 seconds, so about 70% of the whole time. this is assuming the injector is NOT set to double fire and is only firing every 4 stroke revolution. When you see a injector on machine at anything over than equivalent to 2500 rpms, its a steady spray so i disagree 100 % with the 40 hp gain, you may have made other tuning changes and saw a gain but after a certain rpm your injector is spraying a giant stream/fog of fuel, Smitty
Now a direct injected engine, especially a diesel, yeah, I can see by advancing injector timing there can be a power optimization