4.8 boost letdown
There's no way your making 300whp on motor at 5k rpm NA with that 4.8 setup. Best case scenario you'll double NA HP at 15ish psi. So if you limit your self to 15lbs you need to be pushing 300+ NA at the wheels to hit your goal.
As said, try the correct springs and rev it out more. I don't think the LS6 intake will make very good power over 6800 will it? Why are you limiting boost to 15lbs?
As said, try the correct springs and rev it out more. I don't think the LS6 intake will make very good power over 6800 will it? Why are you limiting boost to 15lbs?
Some will disagree, but IMO Spraying the IAT sensor with meth gives you false cool readings. I wouldn’t tune by that number. Better off spraying down stream of the sensor and tuning your actual intake temps.
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Joined: May 2006
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From: Omaha,Ne
Valvesprings, and/or Pushrods.
We had a "low power" condition one time, and found all the pushrods bent, that was with us trying to get away with stock pushrods......on aftermarket springs and boost.
Didn't work.
We had a "low power" condition one time, and found all the pushrods bent, that was with us trying to get away with stock pushrods......on aftermarket springs and boost.
Didn't work.
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My 4.8 made 620 @ 15 psi through a loose converter and th400 on a stock cam. Springs were stock until I hit 25-26 psi then I had valve float. My manifold temps were 95 degrees but I have a huge intercooler, also I built my stainless headers too. Your timing is low compared to mine but if thats what your motor likes on the current combo no reason to pop a motor to try to achieve 600 at 15 psi.
your goals are reachable. especially through a m6. change springs and add a intercooler and run it again. with 11.5 lbs and straight pump 93 my 4.8 made 500 on the nose through a th400 unlocked converter and a s60 rear on a mustang dyno hazing the worn out hoosiers. again your goals are pretty easy and with meth 2 more degrees of timing should be safe.
Last edited by dans94z28; Jun 16, 2014 at 12:17 PM.
My 4.8 made 603 hp and 527 tq on 13 psi with the APS TT kit. I do have worked heads, srings, push rods, E85, and an intercooler going through a glide. Timing ramps up from 13 to 15 degrees. I also dyno'd it Friday, where it was 108 here in Phoenix. IAT's never got over 114 degrees.