I have had the Magnacharger for 10 years now, last week I swapped out the factory cam for a LPE GT2-3, LS7 lifters and BTR springs. Also changed the blower pulley from 3.4 to 3.1. Truck is a 2001 Silverado Z71 5.3 251,000 miles
4L80 transmission 3:73 gears in a 14 bolt rearend. Friday I went to the dyno and to get it tuned. First off I have to say Pat G did an awesome job tuning it, this is the best it has ever run since the 4L80 swap. Shift points now are great.
HP was only 320 RWHP, Dyno showed 7 lbs of boost, I realize my stock exhaust is certainly not helping but I did expect more. Long tube headers are next for sure. Maybe a 3.0 or 2.9 pulley. I was so bummed out I didnt even ask for a dyno sheet actually I was embarrassed to ask for documentation that I`m not making any power. LOL. Anyway what do y`all think? Seem a little low or is my exhaust holding me back a little more than I give it credit for.

 

How big are the tires?

And yes the factory exhaust is choking power big time, on my N/A setup I went from a single 3” exhaust with a turn down to dual 3” with turn downs and I picked up about 4x rwhp just using better mufflers and more flow

 

Tires are 285/75 R16. I know I need to improve the exhaust for sure but its not in the budget right now. Need to buy tires for the wifes truck. I`m thinking 25 to 30 hp gain from headers. I will be satisfied to get to 370-380 rwhp. Truck runs good now that its tuned I should of done that after first installing the Radix.

 

Years ago I had a tvs1900 at 10psi on a 5.3 with a GT2-3 cam. It was lifted on 35s with a 14b rear, full exhaust, and 60e. It barely scratched 400rwhp on the dyno and I was all bummed out expecting in the 500 range. Was a lot of fun to drive though, so if you like your truck dont get too caught up in the HP number.

 

I can also tell you that Kurt's dyno is a heartbreaker. Don't get too wrapped up in the numbers. If truck runs good, be happy. Patrick will tune truck very safe. They also do not always allow for long cool downs to help with numbers. They focus on driveability and safe tune. I bet if you use another dyno, truck will show higher number.

 

See what it traps at the track and then decide.

 

Well for sure I am not knocking Kurt or Pat those guys are great and ya it drives great and feels like it hauls a$$. On the dyno it did 0 to 100 in 10 seconds but that to me seems to easy, not really like on the street. I have not been able to try 0 to 100 on the street yet, to much traffic. I dont think with 320 rwhp its even possible to hit 100 in 10 seconds.
The only time allowed for cool down was while Pat was making adjustments to the tune and down loading it to my ECM.

 

Did you try or at least change to fresh plugs before you went?

 

 

I used fresh NKG BR7EF plugs as per Pats instructions before dynoing. Air temp was 68 altitude in Victoria Tx is 95' here in Buda where I live altitude is 490'. Not sure about intake temps but the blower was only warm to the touch with 68 degree air temp and big fans blowing up under the engine with the hood up.