Belt efficiency

[oil pan 4]

Doing some light reading on belt systems I found a few things.

After reading an ACdelco pdf on alternator efficiency I found that alternator belt power transmission efficiency is some where around 98%.

I have since found another source that back this up and explains belts a little more indepth.

This 98% efficiency only applies to cogged or notched V-belts. Note Cogged and notched V-belts are not synchronous or timing type belts.

These cogged or notched V-belts offer up to a 5% efficiency savings on standard V-belts. Your typical noncogged V-belt can be found on air compressors and riding lawn mowers. These notchless V-belts are usually labled "heavy duty" or "industrial".

This makes me want to swap the belts on my lower powered 1 and 2 horsepower air compressors. I built and rebuilt all my compressors so they all use the same size belts now. Any belts replaced would be set aside as spares on the 4hp compressor that I can smell the belt getting hot when I run it for a long time.

It does not appear that serpentine belts offer any efficieny improvements over cogged V-belts in basic pully systems.
This is because serpentine belts require around 20% more tension than V-belts to do the same job.

I believe the reason people claim serpentine belts are more efficient is due to a matter of prespective.

Say you have 5 or 6 pulleys to run under the hood on a vehicle. If you can run them with one serpentine belt that will be more efficient than running 2 or 3 V-belts. Just because the simple fact that one is less than 2 or 3.

Serpentine belt setups transmit power to pulleys that only have a small radi of belt contact. Something that is not really an option with V-belts.

So if you are only running 1 pulley under your hood you may be better off with a V-belt over a serpentine. That serpentine belt will need more tension which will cause more wear. I have seen this wear in the form of totally blown out front main seals and worn front main bearings.
Having 20% more belt tension on the crank pully from one serp belt is much better than having your belt tension 2x or 3x higher because you have to run 2 or 3 V-belts going around the crank to run all your junk.

This is why we have mechanical engineers.

I may have to try do a test where I swap out a heavy duty belt on my 1hp compressor for a cogged V-belt. Test for a difference in motor wattage draw and compressor RPM, looking for less wattage and more compressor RPMs.

[user removed]

I've seen the ribbed, wider, flat belts go 100k, have sections of the rib missing and still not break, some of the tensioners are spring loaded, and it's a whole lot easier to replace a serpentine with a 3/8 power bar versus replacing and adjusting 3 belts, or even 1 belt not considering access.

It also is great when you can bring all the accessories closer to the front of the engine for service and you just need to get it fed right and let the tenison off the tensioner (or add it income cases) and you're done.

Use a larger alternator and electric power steering for no power steering pump.

regards
mech

[elhigh]

Not only that, Oil Pan, but when running two V-belts they may be on opposite sides of the engine. The net stress on the front of the engine would be a small moment torque from the fore-aft displacement of this belt vs. that belt, while the tensions more or less cancel each other out.

[oil pan 4]

Typically what I have seen on front engine rear wheel drive vehicles with 2 or move V-belts on a V8 or V6 engine tends to follow the cylinders up the engine. They cant put accessories in line with the engine pulley on a horizontal plane because the accessories tend to run into wheel arches or frame.

On a FWD car they might be able to position accessories so belts pulling on the crank can cancel each other out. Then it just becomes nearly impossible to change a belt or accessory on these cars.

[Daox]

Any idea if the goodyear gatorback belts gain you any real efficiency? It would seem to me that they'd bend easier, thus not heat up (and as we know heat is energy), so you loose less energy to flexing. They don't claim greater efficiency on their site, but it seems like it might.

Operating benefits:
-Reduction in operating noise up to 15 dB
-Longer life to standard poly-v belts due to self cleaning effect, better flex capability, higher rib flank contact.
-Improved operating grip and longer flex life
-Belt design to keep consistent performance at high rpm

[oil pan 4]

Looks like with that gatorback belt they tried to take conventional V-belt cogs and apply them to a serpentine belt.
I would bet the efficiency gain would be tiny since the standard cogged V-belt is already 98% efficient.
I wouldn't replace a other wise serviceable belt with this gatorback to try and pick up some efficiency. I think the time and replacement cost wouldn't be worth the savings unless you were in need of a belt change.