Just installed a TVS 1900 on an 07 Chevy Avalanche 5.3L. Running 4-5 pounds boost with stock 3.40 pulley and magnusson tune. Am thinking of pullying down to the 3.10" and should give me 3 more pounds. Guess my question is do I need a new tune? Pretty sure engine can handle 7-8psi boost but dont feel like sending the pcu away again downtime, costs associated with that.

 

The safe answer is to re-tune, of course. Do you have a wideband gauge?

 

Not yet boost and fuel pressure pockets a little light right now but planning on getting one. Suggestions on what brand?

 

Mostly personal preference, I use an AEM, but there's alot fancier ones out there. I'd like to switch to Autometer so it matches my other gauges, but for no other reason.

 

So I called Magnusson today and he told me that he wouldnt recommend pullying down on the 4.8 and 5.3l engines. Says the 6.0 would be a different story. Tells me guy there did it with his 5.3 and the thing went boom. Says maybe with new cam and headers. Thoughts? Wondering what difference headers make?

 

As long as you get a good tune you should be fine.

 

if you change the pulley you MUST recalibrate the PCM. Period, end of discussion. If you want a pulley, call and buy one for 90 bucks.

If it were my truck I would not go smaller than a 3.2.....but what do I know

 

I figured you would be making more boost then that with the 3.4 pulley.

 

I push 8-9lbs with my tvs1900 with a 3.3" pulley

How do you know how much boost you are making?

Definately get a wideband. I like my plx.

 

averages 4-5 odd time i will get 6. Do you have any other mods on your truck to handle boost or is it stock?. What engine do you have?