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Induction noise difference between carb and port injection?
Posted: Sun Oct 08, 2017 9:03 pm
by Circlotron
Just a thought experiment.
Say you had a carbureted engine that you subsequently changed to port injection but used the same manifold, and left the now dry carb in place as a (non-optimal!) throttle body. The intake runners are now for most of their length filled with dry air instead of droplets of liquid fuel. Would this affect the sound of the induction noise much?
Re: Induction noise difference between carb and port injection?
Posted: Sun Oct 08, 2017 9:59 pm
by peejay
That is the setup I have on one of my cars. Induction sound isn't different that I can tell, other than not randomly bogging at low speeds/loads.
Sound didn't seem to change much after I drove the boosters out of the "carburetor" (a 3310) either, although airflow went up a bunch.
Re: Induction noise difference between carb and port injection?
Posted: Mon Oct 09, 2017 6:43 am
by Geoff2
Cannot answer your question specifically, but an 850 cfm Carter TQ [ & even the 800s used on the late XC/XD Falcon 302/351s ] has a sound of all it's own because of the huge secondaries. All 2.25" of them.....
Totally different sound than a 850 Holley or clone...
Re: Induction noise difference between carb and port injection?
Posted: Mon Oct 09, 2017 8:47 am
by Rick Finsta
The IAC tends to whistle loudly on a lot of installs! That is the only difference I noticed when converting over on mine.
Re: Induction noise difference between carb and port injection?
Posted: Sat Oct 21, 2017 11:10 pm
by numboltz
One of the loudest carbs I remember was a warranty-reject rear AFB from a 426 hemi,
re-purposed onto a warranty-reject 383 SB complete with early 4 bolt heads/low-rise manifold
whose only valuable component was a new mopar purple shaft. Lasted for around 80,000 miles of
sustained abuse until a blown upper rad hose during a street race ended in a cracked
block and burned through head. Won the race, BTW. I always theorized that the snivvies
caused the extra noise.
Re: Induction noise difference between carb and port injection?
Posted: Sat Oct 21, 2017 11:49 pm
by MadBill
Snivvies?
Re: Induction noise difference between carb and port injection?
Posted: Sun Oct 22, 2017 9:38 am
by CharlieB53
I have to admit that I also do not know that term "Snivvies".
LOL Sounds a lot like a recently discharged sailor. But I'll bet it ain't.
There could be a great short story behind this.
Re: Induction noise difference between carb and port injection?
Posted: Sun Oct 22, 2017 11:03 am
by stealth
Fuel molecules should absorbe some of the sound energy vs dry manifold. Might only be at certain frequencies though..
Re: Induction noise difference between carb and port injection?
Posted: Mon Oct 23, 2017 5:03 am
by Geoff2
Snivvies, I think he means the distribution tabs that were often attached to the booster rings of production carbs, to try & correct rich/lean cylinders.
Re: Induction noise difference between carb and port injection?
Posted: Mon Oct 23, 2017 5:55 am
by emsvitil
Are all 4 throttle plates moving at the same time or are they still set up as primary,secondary?
I would think with a primary,secondary arrangement it would still sound like a carb when you open up the secondaries.
But if they all moved at the same time you'd not get the sound change of the secondaries kicking in anymore.