im looking at putting a 5" exhaust system on my 2006 silverado lbz but i got one question do i need any back pressure? i have seen just a stright run from the back of the turbo will this hurt her? im running a edge Evolution programmer with 4 stages.. and also one more qusetion what temp will hurt the engine in the EGT's? im after hearing 800 and 1500

the turbo provides all the backpressure you need

Egt's no more than 1350 sustained or
for 15 seconds or less the sky is the limit

The only exhaust that will hurt the turbo/engine is one that is too restrictive. Allbeit that 5" is overkill, it has a nice sound. All the backpressure you could ever need is provided by the turbocharger. With an exhaust that large, you may loose a small amount of power right off the bottom, but this will likely not be noticeable except on a dyno.

As far as EGT's, don't sustain more than 1250 for long periods. I like to stay below that, and try to keep long pulls at 1150 or less. Short bursts of 1450 will not cause any damage, as long as they're kept as short as possible.

I will report back in a day or two on what 5" does for EGT's. Just installed mine and will be hauling tomorrow. I've seen 1200-1250 for 250-300mi almost nonstop and there was nothing I could do about it :(.Had a good sized load,not really heavy just big and was bucking a 30mpg headwind. It was all I could do to hold 65mph.The truck still runs fine although the turbo is non making the boost it used to.

I really like my 5".

Mike S hit the nail on the head. Make sure that your probe is pre-turbo for those temps. 5" is overkill, but does look and sound great.

Got the 5" MBRP on mine and love it. We have service trucks at work 14-15 years old with close to 400,000 miles and who knows how many hours with straight pipe and havn't had any problem. The turbo has all the backpressure u need.

I run 5" on both of my trucks and love it. EGTs are always safe in normal driving/towing.

Is there anyone near Cleveland, OH with a 5". I wanna put on a 4" bc my buddy's 5" is too loud. But hes gotta 99 7.3 powerjoke so I can be for sure.
Thanks