strange turbo noise?

[early99stroker]

I have a question for the board.

Over the weekend I was pulling my travel trailer (9-10K pounds) up a 7-8% grade in my 40tow setting. In 4th(direct) gear I was running 20-21 psi boost and just under 1200 EGT(pre-turbo). When I reached near WOT (around 2400rpm) I heard, in addition to or possibly replacing the normal turbo whine a strange, slightly lower pitch sound coming from behind the radio area. I assume that would be noise from the turbo. The best I can describe the noise is a "Eeeet, Eeeet, Eeeet" type sound. If I backed off the throttle even a little the noise would go away. I wondered if it was an RPM or boost issue, so I slowed down and shifted to third and pinned WOT. The boost went back up to 20-21 psi and RPM's up near 3000, but no noise. Later on the trip when on flat interstate I was shifted to OD and went to WOT the look for noise again. It came back, this time at about 17psi and around 2100 rpm. I tried my other chip settings and it will make the noise in any of them.

Unloaded I can run as hard as the truck will go and no noise will show up even up to 24 psi(the max boost I can make) in any chip setting.

Is this surge that everyone talks about? Could it just be my wastegate opening from drive pressure(I have the red line unplugged and capped)? Is my turbo checking out on me? Could it by chance be the serp. belt(it is OEM 80,000 miles on the truck)?

I've never heard this before, but I've also never ran it this hard since last season when I bought the travel trailer I had many issues that put my EGT's way to high to run this hard (leaky up-pipes, boost leaks).

[Mikes7.3]

I had the same sound and under the same conditions I'm not sure what it is caused by but, since I put the ATS housing on I haven't heard it again.

[lilredpowerstroke]

I know its hard to desribe sounds while typing but was it like a screeching sound?? Mine did the same thing and the second time it did it the turbine wheel spun right off the shaft which the shaft and the wheel are the same piece. Im not tryin to scare you just tellin what happened to me. You might want to think about getting a new turbo or get ready to rebuild yours.

[250downunder]

Certainly sounds like turbo surge. ATS housing is the go. I had the same problem but fortunately fitted the ported housing before I lost my turbo.

[early99stroker]

I think I'm sticking to the surge story. I had a user on another forum post a video of his '02 surging. It sounded identical. I pulled my intake hose and checked the turbine wheel and shaft for play. All was in good shape.

I was shocked, I didn't think an early 99 would surge! Learn something every day.

[strokermann]

i have a early 99 as well do you have a boost gauge. if so look at it when you are hearing the sound. if teh gauge is fluttering then itis surge. i can make mine do it in teh 140 setting on my ts. hope this helps

[Dkahnjob]

This noise that you are describing, I think I have it too. I have a 2001 7.3 with the 4 speed automatic and a 6 position tuner, I run it at +50 hp when towing my boat. When I back off the power just slightly it makes kind of a hiss noise. I assumed that was a normal waste gate noise. Is there something wrong, or something that I should do about it. All seems to work ok, I have kind of gotten used to the noise.
TIA
David

[smoknford]

My 2000 f250 sounds like it is blowing off pressure at medium throttle. The noise goes away under heavy throttle and around town cruising. I thought maybe my wastegate was bad but when i replaced it nothing changed. Took it to a mechanic and they told me i was building boost pressure earlier causing the wastegate to blow. I dont know if it is the same sound. Also my wastegate sounds like that of a 4 cylinder blow off valve. Any ideas?

TIA
Smoknford

[southern7.3]

my 99 makes kind of like an early blow off to kinda like a swooshin noise when i get in it hard for a couple of seconds then it quits. is that surge? what can i do about it??

[Dkahnjob]

It sounds like we are all hearing a similar noise during similar conditions, I am starting to think that it is a normal operating noise. It really doesn't bother me, I just wanted to be sure that I wasn't hurting something.
David