Pulled the trigger on a Trick kit... VS8375 turbo and meth.

Bone stock 2012 rcsb Sierra 4.8 ffv 2wd @111k

Zero modifications, though I have a TH400 and a 3800-ish stall sitting on a shelf, waiting for the rear end and drive shaft. Wheatley is supposed to be doing the first tune.

From what i understand- the injectors will be done around 450rwhp or so, then the pwm pump/fpr will be done about 550ish...

So besides a full trick kit+tuning, what do I HAVE to do to get my 2012 FFV 4.8 to the limit of the STOCK flex fuel system?

Thank you.
-Jake

 

Bigger exhaust wouldn't hurt, but otherwise crank up the boost and let her eat

and be prepared to swap that trans sooner than later!

 

George Conroy claims the FF pump is good for 700's rwhp in his old 408 twin turbo truck. Upgrade injectors and you'd be fine. Throw a trans cooler on that 6 speed to help it last. Good tune and you'll be ready to have a 500 rwhp truck with ease

 

4.8 trucks kept the 4L60e transmission.

I'd get larger injectors right off the bat, go with some 50's or 60's at least. You can find stock take off 6.2 injectors that are 52lb/hr. On pump gas with a decent air fuel ratio they should make around that 450-500hp.

 

Don't think the 4.8s got 6spds, 4L60 que no?

 

Ouch that sucks.. I didn't know that.. That's a bummer. Was the switchover in 13 for the 4.8's? With that being said, either swap to a 80e or even a 6l80e would be an easy swap for that truck. I'd prefer the 6 speed

 

Agreed, 6spd ftw

 

The 4.8 was dropped in 2014 and so was the 4L60e for half ton trucks. All 5.3 and 6.2 trucks for years 2010 to 2013 used the 6L80e.

I think the 4.8's that went into the express vans still went with the 6L80e though, maybe they still used the 4L60e but I can't say for sure.

 

Been looking at 2500 vans 4.8 for my new AC tech and 12 and up are 6spd. Didn't look at earlier models.

 

At what point do I need an adjustable/external FPR? With tuning, can the stock FPR work with boost in the sub 10psi range?

And a 6 speed is in the works... my other TH400 is getting rebuilt with hard parts including a lower 1st/2nd gear. Once its finished, it will get installed with a GearVendors unit- and I will still have less in it than a built 4l80