[kench]

So when I let off the go pedal, I get a cross between a cat hissing, and whoosh of air coming from the truck. It lasts for like a second.

I thought maybe I was hearing turbo noise that I couldn't hear before the 4" turbo back exhaust, but then I read it is air coming out of the larger aftermarket intake.

Can anybody confirm that?

It is really loud when shifting into OD/4 under load while pulling my toy hauler.

Sounds similar to this guy's video:

 

[blue99stroker]

It's normal. It's just air coming back out.
The stock box does it but it's enclosed so you don't hear it.
It's not the wastegate. The wastegate doesn't make noise.

 

[yan7gin]

^ like blue said.

The only downside is you may want to floor it and let your foot off the pedal just so you can hear that noise ?


Sent from AutoGuide.com Free App

 

[7.34me]

hope you respond. It sounds like I have the same issue. Did yours turn out to be the intake after all? Or did it turn out to be something else. I put on a whole new turbo and that damn sound still happens.

So when I let off the go pedal, I get a cross between a cat hissing, and whoosh of air coming from the truck. It lasts for like a second.

I thought maybe I was hearing turbo noise that I couldn't hear before the 4" turbo back exhaust, but then I read it is air coming out of the larger aftermarket intake.

Can anybody confirm that?

It is really loud when shifting into OD/4 under load while pulling my toy hauler.

Sounds similar to this guy's video:

 

[Greg687]

hope you respond. It sounds like I have the same issue. Did yours turn out to be the intake after all? Or did it turn out to be something else. I put on a whole new turbo and that damn sound still happens.

His was the new airbox allowing you to hear what is normal. Yours is probably the same thing, but without more info we can't tell. Turbo's make noise. The freer the intake is, the more you can hear it.

 

[7.34me]

Thanks for the response. The truck is a 2002 f250 7.3 automatic. I have an S&B intake with paper filter and 4"exhaust. After those upgrades, I installed a genuine wicked wheel2 and old school programmer (I forgot the name). When I got to 2500 rpms it made a sudden loud sucking sound and mild sound of metal touching metal. I figured the turbo wheel was striking the housing or the bearings might be shot. I took it apart and there was no play in the wheel; and then put back the old wheel and the same damn thing happened. So I figured I had screwed something up. I decided to take it to a shop and have a new turbo put in. I had them put in a KC turbo stage 2 and PHP hydra tuner with 16 settings. So, the truck definitely runs better and throttle response is much quicker, but now when i get to 2900 rpms I get that same sound. So, I plugged off the 2 intake ports for the S&B filter and took off the plexiglass window from the top of the S&B intake, to force air to take another route and the noise is still there. What are your thoughts?

His was the new airbox allowing you to hear what is normal. Yours is probably the same thing, but without more info we can't tell. Turbo's make noise. The freer the intake is, the more you can hear it.

 

[Greg687]

Do you have any way to monitor the boost pressure? There is a blow off valve that will kick in at 20 something psi. If you are building that much boost it may be opening up. Anyway, you can get a sending unit OBD2 kit that links to a phone app that will monitor a lot of engine parameters, and even do testing for you. The app Torque is a nice "gauge" set, while Forscan is a great diagnostic. Forscan home page has a list of appropriate sending units available so you buy the right one.

 

[7.34me]

Thanks for the info. I was thinking of getting a monitoring/gauge system, I am definitely gonna do it now. I think the Torque app is probably where i will start. Is there a certain amount of boost I should not exceed?

 

[Greg687]

I think the system starts defueling at 29 psi and will throw a code that goes away after boost goes down. If you have a leak in a boot you might also get that odd sound. You can easily build a leak detector to pressurize the system and listen for leaks. Here is one that you can buy, but I made one from a 4"pvc cap, a gauge, a schraeder valve, and a clamp. 3" Dieselsite Turbo Boost Leak Detector

 

[Greg687]

Another thought, if you can record the sound it might help us figure it out.