# Noise from HTD belts



## riwe (Nov 17, 2011)

Hi all!

I use a HTD-8M-30 belt in my boat to transfer Power from the electric motor, Me1304, to the propeller shaft. 

The works very well but it’s a bit noisy. Now that I got my water cooled motor I start to hear other things and the sound from the belt transmission in one of them.

What are your recommendations? I have Heard that some make a groove in the pulley that lets air escape and there are some belts, good year, that have a built in channel to divert air from the belt/pulley.

Has any one tried this?

Changing pulleys and belts to the new eagle standard is not an option. Not for now anyhow.

Best regards

Rikard


----------



## electro wrks (Mar 5, 2012)

This is a problem with the non chevron belts. And, the newer, high capacity carbon belts are even worse noise makers. The word I hear on grooves and holes added to the sprockets is that it doesn't help much. This leaves some kind of sound dampening housing as about the only option left.

Also, if your small sprocket has too few teeth, this could add to the noise problem. Or, if you're approaching the rated capacity of the belts and sprockets, this could add more noise. A more lightly loaded drive may be quieter.


----------



## grip911 (Dec 14, 2011)

I actually enjoy the little noise I hear from mine in the TRIPLE, but the hull of a boat can act as a speaker and amplify the noise. 30mm is not really a big belt to start out with. Maybe the problem is the diameter of the pulleys. On another note ,I would really like to see pictures of your setup if you have any


----------



## Zappo (Sep 1, 2011)

Yeah, I kinda like the noise too. One thing you could do is double check the alignment. If it is off even slightly and the belt rubs the side shields, it will be much louder. I have seen even on much larger industrial applications where 1/8 turn on the jacking bolt on one side will quiet the belt noise a lot.


----------



## riwe (Nov 17, 2011)

Thanks!

I have a HTD-8M-20 running now and its much less noise than the 30mm variant. 

I use hard anodized aluminium pulleys because of the Environment that they are used in. It also saves weight on the drivetrain. 

You are right about the RPM. The high RPM of the small pulley makes it hard for air to escape when the grooves hit the pulley. Im not a big fan of modifying my pulleys since that will brake the anodization. The me1304 and the combustion Engine both run at approx. 3000rpm. I talked to an expert yesterday and he calculated the noise using an application to approx. 76 decibel. 

I will try the HTD-belt that has a groove on top of the teeth. It looks like this: http://1drv.ms/1psjFTl as you can see there is a small groove on top of the teeth that lets air escape.

I dont use a tensioner but I can adjust the tension by lowering or raising the Electric motor. 

Sound proofing will be easier since I use water cooling for both i.c.e. and Electric motor. 

Best regards

Rikard


----------



## grip911 (Dec 14, 2011)

Watched your videos and noticed that the noise was way less than the petrol engine . Was also impressed at how easy the transition from gas to electric and vice versa was.
if you do change to that new strap ,please post and let us know the result


----------



## riwe (Nov 17, 2011)

Hi!

Yes this video, http://1drv.ms/1r2Nn0T , gives you a good run through of the system. Note that this is using the older, noisier, air cooled Me0907. The Me1304 is much more quiet. 

The wroooom-ing sound heard when running on electricity is cavitation from the porpeller, I will change to a 4 blade to next year. The high pitch is from the motenergy. You dont really hear the belt since its a 20mm belt and the Engine compartment is well isolated. 

I will do some testing in my workshop this Winter and compare the different belts. 

Thnks! 
Rikard


----------



## Caps18 (Jun 8, 2008)

I don't know if what you are experiencing is the same thing my car had, but I took my car into the shop yesterday for a noisy belt. All they did was put baby powder on the grooves of the pulley and the noise went away.


----------



## madderscience (Jun 28, 2008)

I'm running a goodyear eagle NRG "blue" belt in my scion xB. There is some noise for sure and it is more than I'd like, but it is acceptable. In my case it may be amplified some what because the belt is relatively long (more surface area to transmit noise) and It may not be tensioned quite enough. Wear patterns after 8000 miles suggest decent alignment and no excessive wear. 

When I inquired with goodyear engineers they suggested a shroud to help contain the noise.

I originally ran a carbon straight tooth belt. That was intolerably loud. The gear ratio was too low as well so for those two reasons I switched to the goodyear stuff.


----------



## joeblack5 (Apr 21, 2009)

Instead of the HTD you could try the power grip GT belts. The profile is slightly different but still compatible. They accept slightly more power for the same size belt.
I do not know the noise but it might be worth a try.

Later J


----------



## riwe (Nov 17, 2011)

madderscience said:


> I'm running a goodyear eagle NRG "blue" belt in my scion xB. There is some noise for sure and it is more than I'd like, but it is acceptable. In my case it may be amplified some what because the belt is relatively long (more surface area to transmit noise) and It may not be tensioned quite enough. Wear patterns after 8000 miles suggest decent alignment and no excessive wear.
> 
> When I inquired with goodyear engineers they suggested a shroud to help contain the noise.
> 
> I originally ran a carbon straight tooth belt. That was intolerably loud. The gear ratio was too low as well so for those two reasons I switched to the goodyear stuff.


 Hey! thanks for the feedback about the EAGLE. 

EAGLE has a lot of things that are better than the HTD. Noise is up to 20 db lower. Its more powerfull which in turn enables me to use a narrower belt.

The noise from a 20mm wide belt is very different from a 30mm belt. 

where did you get your pulleys and belts? Did you find a calculator for dimensioning the belt? 

If your pulleys are far apart you can use a tensioner or just a skateboard Wheel that keeps you belt from vibrating. 

Thank you

Rikard


----------



## riwe (Nov 17, 2011)

hey,

I am looking for someone that can produce eagle nrg pulley to a reasonable price. Aluminum is prefered.

any tips?


best regards

rikard


----------



## madderscience (Jun 28, 2008)

Pulleys came from ebay. They are steel, but they work fine. I set up a filter on the part numbers I wanted and waited. There aren't tons of them but they do show up regularly. You can get Aluminum pulleys but they don't show up on ebay so far as I can tell. The smaller pulleys (up to 40 teeth or 7" diameter or so) have max RPMs around 5000 or so and are pretty well suited to drivetrain use. I think I am currently running a 34/40 ratio.

For example, here is a Goodyear B-40S-SF 40 tooth "blue" pulley, identical to the one I am running on the differential pinion in my scion:
http://www.ebay.com/itm/GOODYEAR-B-...902?pt=LH_DefaultDomain_0&hash=item4140dcab8e

The belt I just used amazon or google shopping and searched around. The belts do show up on ebay but it is a much bigger crapshoot to find one in the size needed.

Goodyear does have an online belt calculator "maximizer pro". Plug in distance between centers, ratio, horsepower, and tolerances and it gives you a bunch of options:

http://www.veyance.com/ProductsDetail.aspx?id=23280

After I got my drivetrain back together with the rebuilt differential, I aligned my belt a bit better than it was (pulleys were parallel but misaligned by about .080) and tensioned it a bit more than before. Still audible, but noticeably quieter. There is a resonance at about 60mph or 4800rpm, that is where it is loudest.

Here is my personal website page on the belt drive in my scion:

http://amphibike.org/blog/scion-xb-ev/scion-xb-ev-construction/scion-xb-ev-drivetrain/


----------

