I will start off by saying what i got so far. So i have a Cam (226/234 109 LSA .525 lift), CIA, Headers, exhaust, home ported 862 heads, bee hive springs, hardend pushrods, ported throttle body and custom tune in a 2000 4WD extended cab Sierra with a 4.8 LR4 gen III.

I just had the thing run on a dyno and i was almost heart broken at the results.. 238 HP at the wheels. I was hoping for so much more out of all that work I did to this thing. I was really shooting for 350 but i am no where near that! How can i get closer to my goal with out breaking the bank? I am new to this performance thing but i am ready to learn and looking for any help i can get. So what is next? It seems as if my hard work was in vain just looking at my results, and i do not want to do things half assed again.. i want to reach that goal this go.

 

All that and it makes what it made from the factory??

Sounds like a bad tuner or the dyno is wrong.

 

Something definitely wrong with those numbers as I made 248 hp stock on a 2nd gear pull with a 4.8.

 

That is what I am saying! I dont know what to think of it all. One thing i can think that is dragging down my HP is my tires, i am driving on 33’s. I wouldn’t think that would make that much difference though

And yes i was wrong.. 230 HP, 238 torque.

 

I have 8.1 injectors but the tuner said i didnt need them because i was only running 69% load on my stock ones

 

The tires hurt it some but it still "should" have made 40-60rwhp over stock with the right tune and all those mods.

It's just hard to say what needs improvement without being able to see the tune file or data logs of it running.

 

I will see if i can get that info.

 

so even if i do find something seriously wrong with the tune i still think i will fall short of my 350 HP goal. Where do you think i should focus my efforts moving forward?

 

I could see maybe 350hp crank but not wheel even with those mods.

Larger engine or a different power adder if you want 350rwhp. There is just so much drive train loss from the 4l60e, the rear end and your larger tires.

 

How much HP do you think the 4L60 loses ?