hi
i have a 2008 silverado 4.8
headers short + cat back GIBSON
pulley SLP
intake system K&N
comp cam
adv dur : 269/273
dur @ .050 : 216/ 220
valve lift : 525/ 532
lobe sep : 114

i dont know whats the problem with my truck all these things that are on my truck and it didnt make a difrence with it
and i took it to a dyno jet it only gave 258 hp 275 torque
is it with my 4.8 engine ?? is it too small or is it with my cam
please HELP!!
what should i do

 

well, with out a tune your not gonna get much. Did you get a pre mod dyno? your only really helpful mod is the cam, everything else is pretty minor. shorty headers are not going to get you much if anything. That cam is fairly mild, an underdrive pulley is what 5hp at most. the intake another 5 maybe.

 

agreed. The best part of that list is the cam.
You really need Long Tube headers to increase the flow over stock manifolds. and Get a TUNE. without a tune your not taking advantage of the mods you have.

 

without a tune I bet it runs like crap

 

guys i tuned up my truck and it still runs like crap
is my cam good enough?? cause the guy that tunned my car told me i should replace it with a GT2-3 cam
please here in kuwait they dont know crap
and also i took it to another dyno and gave it a run he told me that the air fuel is rich 11.09 somthing like that
and also if you know where could i find long headers that would be great give me a site and thaaaaanks

 

what software are you using to tune it? anywhere in the 11's for AFR needs to be corrected. shoot for 12.7 or so WOT

I can only imagine what the fueling and timing tables look like

 

Don't bother putting a new chain on unless you put a decent one on. You already have the upgraded chain anyways..........

 

the gt2-3 cam is a blower cam, its decent NA but nothing spectacular.

 

silva pm me ur details... we managed to get an '07 4.8 with the same mods up to 295hp/300tq...
who tuned the truck for u??

also keep in mind there are pacesetters in shuwaikh.. no need to order from the states unless u wanna end up paying an arm and a leg for it.. i got my american racings for KD470! thats almost 120KD more then what I paid for them..

 

He said he "tuned up" his truck. Probably meanig plugs, wires, etc... I don't think his truck is tuned very well at all.

To the OP, When we say "who tuned your truck?", we mean who used tuning software to reprogram your PCM for the changes you made to your truck. If the AFR is rich your tuner should do something about it.