dcfluid

Funny thing is today I just got my new FX4 Ecoboost and I can NOT hear a whisper of the turbos, but the truck I test drove had a pronounced spool up whistle. I think back now that it was -20c during the test drive and now it's +8c. Cold weather certainly makes things noisier. I was hoping to have enough whistle to demo turbo noise to people.
A very quiet, smooth engine. A buttery low frequency growl on acceleration. All V8's seem noisy in comparison, some for better and some for worse. The 5.4 sounds rough and unsophisticated beside the eco and 5.0.

mcfarmall

There is a little imported "buzz bomb" car, you know the kind with the muffler that doesn't seem to fit under the bumper and has a 4" opening, that drives by my house occasionally. When he shifts it sounds like someone quickly opened and closed a ball valve on a compressed air line...a loud momentary psssssht. That must be the dump valve that the medic was referring to.

I am not going to modify or tamper in any way with my EB after it arrives (stealth gloat ), I was just curious why some turbos are much louder than others.

Personally, I like the fact that there is little that gives away the fact that your truck might be turbo'd. Much like the guy that has a station wagon with a supercharged and nitrous injected engine concealed under the hood.

spdmpo

The biggest reasons are compressor wheel size and shape, air intake design, exhaust design and size, and muffler design. Diesels are a different animal in this respect. And they don't have a BOV, they have a wastegate.
Personally I don't miss that constant whistle of my old 7.3 PSD. Im glad I can't hear these.

mcfarmall

You're probably right. Just like a loud exhaust. It's great for the first couple miles of a long trip but gets really old after that.

bigal1234

It takes power to make noise. No noise, more power to the rear wheels.
Al

mykrrrr

BOVs and wastegates are two different things. BOV helps reduce compressor surge and are generally vented to atmosphere (the pssssh) of a turbo motor or vented back into the intake tract. True that they don't exist on diesels. Gasoline turbo motors have both. Wastegates help hold max boost pressure.

http://en.wikipedia.org/wiki/Blowoff_valve
http://en.wikipedia.org/wiki/Wastegate

p38fln

Judging from the picture on Wikipedia, the Ecoboost definitely has a blow off valve, its one of the few things you can actually see looking down from the top.

varithms

Put this on a player and run it through the speakers

Leadsled124

Im not sure if theres any intakes on the market yet but usually any sort of cone filter and you can hear you turbo more as well as the bpv. These trucks do not have "blowoff valves" they use a recirc bypass-valve that redirects the blowoff into the exhaust so it doesnt pollute. Blowoff valves are illegal and usually concidered ricer on the street unless you have a serious amount of power that a bpv cannot hold. Blowoff valves release to atmosphere, and since you truck already metered the air to create a air/fuel mixture, if you blow it off the result is a super rich and possibly unsafe afr.

If i listen really close i can barely hear the turbos. You wont hear them from just reving the truck either because boost is load driven not rpm. Even on my STi you can barely hear the turbo with the factory filter. Just throw any shortram filter on and its very apparent. I would just be worried about putting on an intake without a tune on a turbo motor

supermech21

Intakes dont normally net a big return in power. I would venture to say the computer could compensate for the extra air that the intakes would provide.