Bigger DP need Tune?

[Toadvine]

Ok so more or less I'm posting this question up for my mom.

My brother has a 2001 GMC Sierra 1500. So far he has put a four inch catless exhaust on the truck. He just recently bought a 3inch downpipe. I am not to familiar with diesel trucks but I know that when you start messing with a DP on Subarus you need a tune. So my question is does my brother need a tune if he installs this DP? My mom is afraid my brother is going to blow his truck up. My uncle and I both tried to tell him he would need a tune but he insists he doesn't.

Thanks in advance

 

[Molson02536]

Ok so more or less I'm posting this question up for my mom.

My brother has a 2001 GMC Sierra 1500. So far he has put a four inch catless exhaust on the truck. He just recently bought a 3inch downpipe. I am not to familiar with diesel trucks but I know that when you start messing with a DP on Subarus you need a tune. So my question is does my brother need a tune if he installs this DP? My mom is afraid my brother is going to blow his truck up. My uncle and I both tried to tell him he would need a tune but he insists he doesn't.

Thanks in advance

You need a tune, once the exghuast temprature starts to get to hot from running lean. the PCM will tune the engine down causing less HP. And no worries about the engine blowing it self up, the OCM will try to keep that from happening.

There is a good chance that he's going to burn out his turbo unless he upgrades the oil lines for better flow to keep it cool.

good luck and keep us posted.