Need help to diagnose a problem

[explosionFTL]

I have a 7.3 ex with 66k miles with an AFE intake, 4" MBRP, dp tuner, and overboost anhialator that were recently installed. I am noticing a hissing sound from the engine when I am on the highway and begin to accelerate. The hissing happens in high gear and the acceleration is affected when this happens.

Does this seem like a boost leak? Compressor surge? Wastegate failure? Tranny failure? Other ideas??

Thanks in advance.

[NorCalDiesel]

Originally Posted by explosionFTL

I have a 7.3 ex with 66k miles with an AFE intake, 4" MBRP, dp tuner, and overboost anhialator that were recently installed. I am noticing a hissing sound from the engine when I am on the highway and begin to accelerate. The hissing happens in high gear and the acceleration is affected when this happens.

Does this seem like a boost leak? Compressor surge? Wastegate failure? Tranny failure? Other ideas??

Thanks in advance.

The hissing could be a couple things. But you shouldn't be able to hear to much under the hood over the noise of the motor.. I can't, but more importantly you have added a tuner and boost fooler and no gauges. What are your EGT's? If you do have a boost leak and your adding more fuel using a tuner your EGT's are gonna be high and could damage your exhaust valves / piston's.. Aluminum melts at 1220*F

Not a good idea. Get some gauges and let us know what you numbers are when your at WOT and driving at speed down the freeway.

With what you have you should be seeing approx 23 - 25 lbs boost, maybe 28lbs at WOT. BTW, the stock turbo will not like those compressor RPM's and running it above 21 - 23 lbs tends to wear the thrust bearing quicker. They just aren't made for those Quill/shaft speeds... the journal bearings are smaller as are the thrust bearings when compared to GTP 38R's and any larger frame compressor.

Did you adjust the Pressure Regulator on the Anihilator? It sounds like you have a leak if your dropping off the power curve early.

[explosionFTL]

I am on the process of installing gauges. I will complete tonight and post the data. I did not adjust the Pressure Regulator on the Anihilator. Thanks for the fast response.

[explosionFTL]

I installed the gauges last night and here is what I found out:
Please note that I was driving in town with no load.

Tranny temp hung around 150 deg F
EGTs were 300-400 deg F at idle and jumped as high as 1100 at WOT
boost jumped as high as 24 psi at WOT but remained around 10 during normal driving

I am getting a flutter noise after high boost during shift points and letting off the throttle. I am also noticing the same hissing noise in high gear during acceleration. The boost will build but builds slower in high gear.

Any help or guidance is appreciated. Thanks.

[NorCalDiesel]

Those numbers all look fine. It sounds like turbo surge or stall. Look at your boost gauge when you're noticing the hissing, is the needle fluttering? The air coming into the compressor housing is buffeting across the compressor wheel vanes disturbing the airflow into the compressor. You want to stay out of that situation because it will shorten the life of the turbo.

This is common. Ford changed the comp wheel to make them quieter in the SD's and this is the result at higher than normal turbo RPM's, surge.. It is remedied using a Wicked Wheel or aftermarket compressor housing.

[explosionFTL]

So I have a better description of the problem now that the gauges are in...

I notice a hissing sound from the engine (like blow off) when I am between 1500 and 2000 rpm. I notice the noise especially when I am on the highway and begin to accelerate. The vehicle accelerates very slowly and it wont boost past 6 psi during this range but as soon as I exceed 2000 rpm the boost will build like normal (up to 26 psi).

Surge???

If so, I plan to purchase a wicked wheel and ported housing. Is the install difficult?

[Carpenoctum]

So did you ever figure this out? I have a 2003 ex with the exact same setup except i don't have the annihilator. I have the same hiss under slight acceleration around 7 psi of boost and the compressor flutter when pushing hard. I've also noticed less power in the upper range but i think that's due to the hpop falling to around 1800 psi at 100% pedal on the hwy. I can't push the Dp Chip in the highest Hp setting because she'll smoke and push the exhaust temps to high. Thinking T-500 and a Chip reflash might help fix some of that.

[explosionFTL]

I assumed it was surge and installed the ATS housing. Great sound but hiss and lag is still there, maybe not as pronounced.

[Carpenoctum]

I used to get a loud waste gate release when it shifted hard under load. So I removed the air bleed on the red line hooked it back up like normal and run the Dp on 80hp. Not sure how much boost I'm getting because my edge gage only goes to 21 and it'll go past that. I had to ground the MAP sensor to stop getting codes. Runs the same but pcm only sees 15 max.
Planning on doing a intake pressure test this weekend to check for leaks. Not sure if any of that helps but things to think about or try.