exhaust sound

[opey450r]

i have a 07 pete 379 with 565. have 7 inch straight pipes and when it get to around 1500 rpm it has a weird sound up in till 1700. has anyone else had that problem. we have a 05 tractor with same motor with same pipes but it doesn’t have that sound. no exhaust leaks all brand new from y pipe out. hard to explain noise with words. when you back off throttle a little bit the sound goes away and sounds like it should

[marek4792]

Is it like a hum that resonates?

[Lonestar10]

ive noticed when pulling with mine after about 1550 the engine tends to get a sort of harmonic resonance sound engine almost sounds like its running better at that point and higher but no real change in power.

[opey450r]

no it sounds almost like an exhaust leak then goes away. kind of like motor gets out of wack the comes back no power loss just sound completely different at those rpms

[Rawze]

(12-16-2018 )opey450r Wrote:  i have a 07 pete 379 with 565. have 7 inch straight pipes and when it get to around 1500 rpm it has a weird sound up in till 1700. has anyone else had that problem. we have a 05 tractor with same motor with same pipes but it doesn’t have that sound. no exhaust leaks all brand new from y pipe out. hard to explain noise with words. when you back off throttle a little bit the sound goes away and sounds like it should

Is the truck de-mandated? if so, who did the work?

how much boost is it making when it does this?

[opey450r]

no she’s factory and around 35psi