I have an 05 Red Stepside RCSB Supercharged 5 speed. My biggest concern is lack of performance, truck is very responsive at low rpm, has plenty of torque in 5th through the hills but when you stand on it going through the gears there doesn't seem to be what a stock 4.8 should have. I am the 3rd owner and don't know the history or if these trucks come with a programmer or maybe a dealership has tuned it to stock numbers, it has a JG cover over the ACL link. Any help would be appreciated.

 

Also do these trucks have and kind of limited slip or locking diff. or under another RPO code? No G80 code in glove box.

 

I would put a smaller pulley on the supercharger, and get a custom tune from Wheatley or Klugg.

 

I had it on the dyno Thursday of last week just to see what it had for a tune, boost and to see if it had other problems, made 308 hp and 351 tq but hit speed limiter (125) at 4800 RPM's and 5.5 lbs. boost so don't know what max was. Long tube Texas Speed headers, off road Y and a 3.3 pulley will be in tomorrow. Going back to dyno and kill speed limiter and have a tune, expecting some decent numbers.

 

or dyno in third

 

Dynoed again today with 3.2 pulley, Texas Speed headers, offroad Y pipe and made 345.80 Hp and 394.36 Tq but chunked the driveshaft at 4800 rpm's, was still making good power and we had a safe/starter tune in it. Who makes a good driveshaft?

 

make sure you upgrade your fuel pump when going to the smaller pulley the Gibbs trucks come with stock fuel pumps because of the lower boost numbers they run stock.

 

Have somebody check the Tranny. I replaced mine in April with only 75K miles on it. Just driving it after I picked it up, I could tell a a huge difference.