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Loud engines

3K views 21 replies 19 participants last post by  melmount 
#1 ·
Why are the 7.3s so loud? The crank case noise with the windows down can be quite loud accelerating from idle. The exhaust is quiet. I noticed other newer diesels are a lot quieter. :dunno:
 
#3 ·
Injectors I guess..
 
#4 ·
I was told it is the injectors..true?
 
#5 ·
Injectors .. A fuel cross over kit and help dampen a little.
 
#6 ·
Yep. The main reason that Ford went to a split shot injector over the OBS single shots was for emissions and they were quieter. After that, they put the injectors in a "soundproof" box on the 6.4, and now they are running electronic piezo injectors. The clatter that you hear on the 7.3 is the injector hammering shut. That's why the new ULSD fuel is hard on injectors because sulfur was originally in the fuel as an ultra high pressure lubricant. Bear in mind that your injectors are operating at 25-35000 PSI several thousand times per minute. So yeah, their gonna be a little noisy.
 
#21 ·
Wait, 25000-35000?!?!

Where are you gettin your info?

We don't even get that at the nozzle, after the intensifier piston has amplified injection pressure...

Try 3000, maybe 3300 in a spike, inside the top of the injector.

And IF everything inside that injector is in good shape, about 21000 at the nozzle.

And several thousand times a minute? Try a bit south of that, even at redline.

They're loud, especially at idle, because they're running at about 3500 psi AT THE NOZZLE. No injection quality. The HEUI characteristics of the injector don't help either.

They just dont realise that your 99 has the single shot injector while ours has the split shot. My friend and i were talking about that just the other day...
:doh::doh:

50 state trucks stopped putting single shots AA's (90cc) in the truck in 96. Starting in 97 Cali trucks through the E99's, had AB injectors (130cc).

ALL 8 injectors on an E99 are AB code. AB code injectors are ALL split shots. The reason an E99 will sound louder than a 2000 is because it does not have a "long lead" injector in the number 8 cylinder.

Firing order on a 7.3 is 1, 2, 7, 3, 4, 5, 6, 8. Front to back on the drivers head, 2, 4, 6, 8. Passenger head front to back, 1, 3, 5, 7.

The fuel rails on ALL superduties fed from the front in factory form. So, the number 6 cylinder fires immediately before the number 8 cylinder, starving it for fuel, further degrading injection quality, increasing noise.

So, in 99.5 when they swapped to AD code injectors (140cc Split Shot) they incorporated a "long lead" (AE code) injector in the number 8 cylinder, to quiet this noise...
 
#8 ·
Oh I enjoy the sound too. Just one more question you great people have answered for me to satisfy my curious mind! Thanks
 
#11 ·
Ah... me and my roommate were wondering this as well the other day. I've got the 7.3, he's got the 6.0, and another friend has the 6.4. We've noticed that they seem to get quieter as the generations progressed. I definitely like the noise on mine! Makes it sounds super beefcake! Haha!
 
#12 ·
I love my 7.3 sound. You can barely hear the new 6.7.
 
#15 ·
my 99 is the loudest thing i've heard. It doesn't sound like a good sounding diesel at idle but it runs great. The injectors really sound like crap next to a 2000 model year and earlier. When i pull up and the gas station or any local shops they ask whats wrong with your truck and why does it sound like that...tell em it has sounded like that since i've had it and it still runs fine
 
#16 ·
ha ha ha :hehe: you should have heard my 90.... i converted it from e40d to a zf5 with a single mass flywheel. you couldnt hear yourself think outside of the truck when it was idling, from the gear roll over noise. i sure did get a lot of looks at gas stations and such.
 
#17 ·
They just dont realise that your 99 has the single shot injector while ours has the split shot. My friend and i were talking about that just the other day...
 
#18 ·
hey these 7.3s are loud..but u think these are loud...listen to a cummins.. .those puppies are barkin!! haha But the noise has to do with the injectors on the 7.3 engines.. they take most of the noise :)
 
#22 ·
Common rail fuel injection makes a lot of injector pressure, over 25000 psi.
ps: the sulfer in the fuel was not the lubricant. We dont need the sulfer. The process of removing the sulfer also removes the lubricating properties in the diesel fuel(which we do need).
 
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