Blow off valve?

[macgyvr]

I don't know much about these trucks. I have exhaust from the manifold downpipe and back with nothing but a small muffler. I have an afe air box/filter. H&S minimax on the mild tune.

2008 F350 4x4 Crewcab dually.

While pulling my 34 ft bumper pull with two rigs and a truck camper when I'm pulling a grade and the motor kind of bogs down(like you should've made the trans downshift)? it will build pyro. When it gets up to about 1000 to 1200 degrees when you let off of it there is a noise that sounds like a blow off valve or something...not sure but sound like its coming from the area of the air box.

I didn't own this truck long before i deleted the exhaust and added the airbox and tuner so I don't know if this sound was there before, I never heard it on my all stock F450.

All systems seem to be working properly and its been deleted for 2500 miles.

mac 'hope its normal' gyvr

[Antonm]

I think what you are hearing is what is a known as a "turbo fart". My truck does the same thing. I'm pretty sure your stock 450 does it , you just can't hear it as well with the factory air box in place.

[strivingfirst]

it sounds like what mine does, so yes its normal and fine if everything else is running well. I would be more concerned about lowering your EGT's. You can get a good water/methane kit for a reasonable price which will help a lot. What tune are you running while towing? The truck should have more then enough power for those pulls. I also bumper pull on some really steep grade, about 14,000lbs (yes i know what its rated for), Also what gear do you think you're in when it "bogs down"
keep us posted,
Dom

[macgyvr]

I'm usually towing something like this.



Total combo is around 25k, trailer is about 15k or so.

Its not that the grades are that bad, its that the speeds are low enough that the trans is in 5th while trying to go up an incline at 50 or 55...so I'm not building enough rpm to build the power. I want it to down shift but I think I'm being too much of a pussy to put the pedal to the floor so that it will downshift. Normally I like to build some speed coming down the grades to have it going up the grades, but when its a two lane road and grandma is always in front of you...it kills me.

I'm running the mild tune on the minimax.

I kind of figured this noise is something that may have been there before but the stock air box covered it up.

mac 'still learning' gyvr