whats going on here?

[th3]

just installed a 4" turbo back pipe w/kittymuff delete. i noticed that at start up with cold engine i get a deep tone comming out of the tail pipe for a second or two then the hiss and whistle start. what is causing the deep tone? is that because the turbo hasnt spooled up yet?



i also have an idle surge every now and again while at a stop sign or drive thru and noticed that the deep tone comes back while the engine surges. its almost like the exhaust has a turbo bypass valve kicking in or maybe the turbo sticks and stops or something. i just dont know enough about turbos to figure this out. whats going on here?

[Ricemiester]

The truck has a VGT, which means Variable Geometric Turbo. It uses oil to operate it. When u first start it its doing exactly what it's always done now that u have the exhaust on it you can hear it.

[westcoaststrokin]

Yep it is a completely normal sound for a straight pipe 6.0. Mine sounds the exact same way.

[th3]

ok, so the veins are all the way open at start up? what about the deep sound comming back when the engine starts that idle surge problem that so many 6.0's have? is the idle surging related to the turbo veins opening all the way up at idle when they are not supposed to?

[Ricemiester]

Does the truck ever perform poorly? if so u may have a VGT solenoid issue. The only way to test this is with a scanner and watch the percent at an idle. It should hover around 70%

[th3]

not really. friend has a 02 4x4 f250 cc sb 7.3 and has to run his quad zilla tunner on the first tune over stock to keep up with my 04 4x4 f350 cc lb 6.0 when it was bone stock. with the new 4" i can feel allitle more power. i feel like its been doing good, no poor performance. bro-in-law gots a fancy scanner, ill check it this weekend anyway, thanks.