The Siren Board

:TBolt: I am a little confused with the thunderbolt blower types.
All I know (and may not be correct) Is that the A1 blower is the quietest and has the 'Pulsey' sort of sound. I am not certain of any others? Could someone explain and possible find videos of sirens with different blowers so I can try and find a difference with hearing. Thanks! Tom :TBolt:

The blower used on the A1 series was the size 6M blower, which has a 6 inch intake and a large pulley on it. Due to the large pulley, it runs at a slower speed which creates the pulsating sound, and is why A1 thunderbolts are usually not quite as loud. Here is what a 6M looks like (video not mine):


https://www.youtube.com/watch?v=IbkVQgk1ro4

The 5M blower was used on the early A2 thunderbolts and is usually regarded as being the loudest, having a 3 inch intake and a somewhat smaller pulley. This blower model is not quite as common since it was only used for part of the A2 series. Here is an image of my 5M blower (the gas engine is a custom addition of mine):


The 4M blower is the most common blower, being used on the later A2 series, B series, and C series. Its sound output lies between the 6M and 5M blowers, and has a 1 1/2 inch intake with a small pulley. Here is a video of a 4M blower (not my video):


https://www.youtube.com/watch?v=HpSJwDzO-AY

I hope that I could help .

Thank you so much!

I'd like to add though that the "loud" portion of said blowers affects the single and dual tone heads differently. For example, the 6M due to its slow running gave it a smooth distorted sound. A dual tone 6M might appear a little quieter than the 5 and 4Ms. The 5M gives the dual tone head a very loud buzz and seems a quite a bit louder than the 4 and 6M (but also consider it has twice the airflow as well. 320 CFM I think? My thunderbolt ran off one.) The 4M is the most common. Now on single tone heads the bigger blower doesn't seem to affect the sound as much when we talk about 4 and 5M blowers. It may or may not have been louder but honestly it's sort of hard to tell. The 6M however because of the pulsate (and because the original single tone bolt was designed around the 6M) seems like it is definatly louder than the other 2... not by a whole lot but yea it does seem a bit louder. But if you can, listen for yourselves!

I believe the airflow and sound ratings are as follows:
6M: 300 CFM, 128 db on a dual tone, 129 on a single tone
5M: 350 CFM, 129/130 db on a dual tone, 130/131 on a single tone
4M: 250 CFM, 126 on a dual tone, 127 on a single tone

I have found that the 6M has the attention grabbing "pulsating" sound, but seems to be ever so slightly quieter than the 5M (at least on the single tone model), however they both pack a serious punch. Here are some videos that compare a 5M Thunderbolt 1000 to a 6M Thunderbolt 1000 (not my videos):

6M:


https://www.youtube.com/watch?v=GO2zKyMtBV4

5M:


https://www.youtube.com/watch?v=btGnOr-OSPI

Okay I am getting an understanding now, Thank you all!

Yea maybe. I know that my baby ran off a 5M or I'm pretty sure anyway given the date and the blower case.

Sorry for a bit of a bump but if you want to be able to tell just the blower apart by sound then the 6M blower makes a pulsating noise, the 5M makes kind of a humming sound with a hissing undertone and the 4M makes a LOUD humming sound.

Has anyone installed a smaller pulley on the 5m or 6M?

Greenfield it depends on single or dual tone. But yes usually 6M blowers have a pulsating sound.