The truth and facts about noise level in gas RV's vs DP's..

[skypilot_1]

Originally Posted by Mike and Cha

Skipilot, all MH's are not built the same, hence why they do reviews such as the one you quoted. One persons opinion about one MH tested is hardly an honest review of how all F-53 Chassis would perform in all Class A MH's. You get what you pay for and some manufacturers do a much better job at engineering the MH to the chassis, add handling components, different wheelbase, chassis size, weight distribution, and sound deadening materials. I wouldn't base any decision off of reviews I've read in any magazine. The best critic would be the purchaser of the MH, and they should drive several brands of Gas MH's and they would be pleasantly surprised.

Very well said.
While aiding a friend research new class A gas rigs to purchase. I found what Im sure all of you nice folks here already know.....there's only one power plant available, no mater what size/weight rig your looking at. There can be 10k#'s difference in GVWR, but HP and torque are the same. At the low end your looking @ 50 lbs per HP, and the high end 81 lbs per HP. Not what Id call a satisfying selection. So if you want performance go small.

[LVRVLUVR]

Originally Posted by skypilot_1

Very well said.
While aiding a friend research new class A gas rigs to purchase. I found what Im sure all of you nice folks here already know.....there's only one power plant available, no mater what size/weight rig your looking at. There can be 10k#'s difference in GVWR, but HP and torque are the same. At the low end your looking @ 50 lbs per HP, and the high end 81 lbs per HP. Not what Id call a satisfying selection. So if you want performance go small.

so what has more power per lb??? gas or diesel??

[LVRVLUVR]

Originally Posted by LVRVLUVR

so what has more power per lb??? gas or diesel??

it's a simple question and simple answer... diesel..

6.8 diesel...660 ft lbs(the lower rated )

6.8 gas ...362 ft lbs ( the higest rated)

[Timon]

Couple things about taking sound level measurements.

First the position of the microphone should be as close the the listening position as possible. Having it down by the steering coulmn candy give a much different reading then near where your ears are.

Another important issue is the scale used. These are labeled A, B, C, D. The A scale is closest to the human ear so it's the best to use for these tests.

Many sound level meters allow you to unplug the microphone and add an extension cable so you can remotely place the microphone. This makes it easier to take readings and still see the meter.

Just some thoughts to consider.

[Crabb E]

Originally Posted by LVRVLUVR

it's a simple question and simple answer... diesel..

6.8 diesel...660 ft lbs(the lower rated )

6.8 gas ...362 ft lbs ( the higest rated)

6.8 gas...362 hp/457 ft lbs

[CaptBill]

I've had both gas and diesel motorhomes, and that little sound level meter doesn't mean a thing when it comes to the actual experience of day-long drives over differing terrain. There just is really no comparison.

And although I only read 5 or 6 of the 9 pages, I don't remember seeing the OP telling everyone that a 3db decrease in level is actually cutting the volume IN HALF, while a 3 db increase, is DOUBLING the volume. Increase the noise by 3 db again, and what you're hearing is now twice as loud as it just was.

So the meter can fool people into thinking that, 'awww, is not much louder than that other coach... it's only 3 db higher'.

I know the readings in the photos were both of the gas coach, but that's not the point. The point is, a reading of 73 db is twice as load as a reading of 70. A sound level of 76 db, is 4 times louder than 70; etc. That's what you're hearing, and that's what matters.

[WeBRVing]

Originally Posted by Crabb E

6.8 gas...362 hp/457 ft lbs

X2. That's what our gasser has.
The new 2017 V-10 has 460 ft-lbs of torque according to the Ford website.
I can have a normal voice convo with wifey, pulling a 6-7% grade at 4000+ rpms, with the fan clutch engaged.
I don't know where folks get the notion that gas RV's are overly loud. Our 1978 Pace Arrow Dodge 440 4bbl was fine also, normal voice.
Granted, they are louder than a DP, but I like to hear my engine. Makes it easier to detect a potential problem.
Just my 2c.

[WeBRVing]

Originally Posted by LVRVLUVR

so what has more power per lb??? gas or diesel??

Depends on your definition of Power.
Diesel=more torque.
Gas=more horsepower.
The above are generalizations. I know there are 45' DPs with 500HP out there.........

[Timon]

I suppect how loud a coach will be much more dependent on how well the manufacture sound insulated the engine compartment. Some manufactures will be very quite and others very noisy however even a noisy one can be quieted down with additional insulation.

[Algonquin]

Originally Posted by WeBRVing

Depends on your definition of Power.
Diesel=more torque.
Gas=more horsepower.
The above are generalizations. I know there are 45' DPs with 500HP out there.........

Power is measured in horsepower PERIOD. A gas engine can have, for example, half the torque of a diesel and still produce the same horsepower as the diesel. The problem is that the gas engine has to turn at twice the RPMs as the diesel to make the same power. This is obvious when going up a steep hill in with a V10. Not good for noise, durability, or fuel mileage.

Power = Torque X RPM X constant

[stepside454]

Actually torque is measured ,
Horsepower is calculated .
TxR divided by 5252= horsepower

[Steve Ownby]

Originally Posted by Algonquin

Power is measured in horsepower PERIOD. A gas engine can have, for example, half the torque of a diesel and still produce the same horsepower as the diesel. The problem is that the gas engine has to turn at twice the RPMs as the diesel to make the same power. This is obvious when going up a steep hill in with a V10. Not good for noise, durability, or fuel mileage.

Power = Torque X RPM X constant

This is correct, as is Stepside. If you look at the hp and torque curves of a Diesel engine, it's apparent why they are so good at seemingly moving weight effortlessly.

My diesel (Cummins ISM) reaches its max torque at 1200 rpm. It's torque is essentially flat up to 1600 rpm when it starts dropping off. At this rpm the engine is within 25 hp of its max which occurs at 1800 rpm. At 1800 rpm, the torque is still within 100 ft lbs of the max which occurred at 1200 rpm. This means, at 1425 rpm at 62 mph, I have 425 hp available and essentially max torque of 1550. This means full hp & torque are on tap at practically all highway speeds. Makes driving seem effortless.

[Coma]

Torque= Force
Work= Force X Distance
Power= Work/Time

Back to the measurement of the sound level, the device used needs to be calibrated regularly. It's biggest drawback is the frequencies it samples. Good ears hear from about 20 Hz to 20000 Hz. We older folks probably have lost some high frequency, I know I have. The device, even if calibrated properly, measures ~30 to 8000 Hz. It measures less than half of the normally audible spectrum.


http://www.extech.com/instruments/re...7732_UM-en.pdf

[Algonquin]

Originally Posted by Coma

Torque= Force
Work= Force X Distance
Power= Work/Time

Back to the measurement of the sound level, the device used needs to be calibrated regularly. It's biggest drawback is the frequencies it samples. Good ears hear from about 20 Hz to 20000 Hz. We older folks probably have lost some high frequency, I know I have. The device, even if calibrated properly, measures ~30 to 8000 Hz. It measures less than half of the normally audible spectrum.


http://www.extech.com/instruments/re...7732_UM-en.pdf

Technically, Torque is not a force, but the result of a force acting perpendicularly at a given distance. Hence the units are in pound-feet. For example, 10 pounds acting at a distance of 1 foot would produce 10 pound-feet of torque.