I have a 2004 Silverado 1500 regular cab 5.3L Volant CAI, Pacesetter shortey headers, Dynomax exhaust & Radix. I did a baseline run on a Dynojet. Motor was 100% stock and ran a 235hp. After adding CAI, headers and a exhaust the truck pulled a 248Hp which I felt was a bit low. The big kicker for me was after the Radix install the truck pulled 330Hp. That does not seem right especially with the extra air and exhaust flow that was added. Any ideas why this may be or does everybody feel this is about right? Only thing I could think of is the exhaust system is not too good but would that be this noticeably. Considering dropping pulley down one or two sizes and getting a custom tune. Boost gauge not yet installed. Hope to do that on next days off. Thanks.

 

well you only have shorty headers which probably added about 7 hp, your exhaust maybe 7 and your intake maybe 5 so that seems about right.

As far as the radix, who tuned it? What pulley are you running? Yes those numbers seem low but if it's an untuned truck with only 4 lbs of boost or something like that then that would explain your sub par numbers.

 

yep, need more info.
which pulley
what tune- stock Radix ?
psi

 

+1
Tuning will totally wake it up. You did gain 100hp with a couple of bolt ons and the SC.

 

From what everyone is saying it is probably the tune. It is the Radix tune which I figure is a very conservative tune. The pulley size is what came with it which you all probably know more than I do but I think it is about 3.4"-3.5" As far as what boost I am running I have not yet had the chance to hook up the gauge. It should be delivered sometime at the first of the week. After talking to the guys at TBYRNE Motorsports they are syaing that going with one of the mail order tunes they offer and a 3.10" pulley would get my numbers up where I want to be and the boost would be around 7psi. With that being said is 7psi safe on my motor? And will fuel pump and injectors need to be upgraded? Pump and injectors are the ones that came with S/C system not sure what size they are. Does anybody see any other options or better options? I don't have a place near that will laptop tune a Silverado so I am stuck with mail order tune. Would TBYRNE Motorsports be a good choice? I drive this truck daily for now so reliability is a factor. I am new to all this so any info you have will be appreciated.

 

The fuel pump and injectors will be fine for 7lbs. BTW the size of the pulley is stamped right on the front of it. Where are you located?

 

That's nice. I have taken newbie to a whole new level. Pulley is 3.4" I am located in Lumberton, TX about 5 or 10 minutes north of Beaumont

 

Hey, how were you supposed to know?

There are a few good tuners in Texas, I know it's a big state but it might be worth the drive to a good Dyno tune.

 

Alright I appreciate it. I guess I will do an internet search and see what I come up with.

 

A 3.1 pulley should get you more than 7psi on a 5.3. I'm seeing 7.5lbs with a 3.3 pulley.