Thanks for your reply. I don’t work for the said dead man and in no way associated with his company. Any how I request you to through some light in generalized words.
Lugging boom is the loud low frequency (firing frequency) noise you get when you run the engine at a reasonable throttle opening, at fairly low rpm, such as when you stay in top gear going up a hill.
There are several causes, and many cures.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
You have high levels of low-frequency inputs because of the low firing frequency at low engine speeds. High levels because of the high loads.
It would be worse with a 4-cyl engine than with a V-8, for example, because of the lower frequencies at a given RPM.
Considerations?
One is to make sure that your exhaust system doesn't have a primary acoustic mode identical to a cabin acoustic mode.
Then you'd have something like the "Corvette boom" noise.
Another is make sure the powertrain in general and the exhaust in particular is well-isolated from body panels having low-frequency modes.
Another is to assure that items like a transmission support cross-member don't have resonances in undesirable operating frequency ranges. Early Jeep Grand Cherokee, for example.
