The Siren Board

Hello, I have a Thunderbolt 1000 head that I am currently in the process of restoring. When I got the siren it did not come with the roots blower. I am going to mount it on an old jet ski trailer so I can move it around. My question is what kind of 120v blower should I use? I am currently using an electric leaf blower but I know that I need pressure, not CFM. Please keep in mind that the motor needs to be 120v. Any help would be appreciated.

With those kind of power constraints your best options are probably going to be leaf blowers, hi-powered shop vacs, and pneumatic blowers like the ones you see at the motor bank or Home Depot. Even just a little air blown into the chopper tube makes a difference. I have used some shop vacs in the past, and the do a good job of giving the siren some bite. Obviously it's not going to be anything near what the roots blower would produce, but for smaller scale running, those options seem to work pretty well.

We used both a shop vac and a leaf blower to supercharge mine back before I put it on the blower. It definitely added some volume to it, but it would starve for air even with the chopper level on it's lowest setting.

video: http://www.youtube.com/watch?v=r5k6cIPwfa8

One of those big blowers like they use to inflate those bouncy houses or whacky flailing arm inflateable tube men would work great. They move a lot of air. Here is one for under $100 new: http://www.amazon.com/Premium-Inflatabl ... rge+blower

The bank tube blowers Eric Green used worked great also.

I know that I need pressure, not CFM

No. You need volume not pressure. The Thunderbolt blower is 250cfm at only about 6-7 psi.
If you find something that moves a lot of air like a good-size vacuum motor then it will give it a decent kick.
I should pull one of my bank tube system vacs apart and see if there is a model number on the vac motor.
Those things really do fill out the sound when running through a Thunderbolt chopper.

As a thought, since many T-bolts are now being bought purely for their blowers, maybe someone who has a T-bolt head but no blower could basically build their own blower by taking a marine or automotive supercharger unit and mating it to an electric motor to drive it instead of running it off of an internal combustion engine? Just from about ten minutes with Google, it looks like the Vortech V-5F and V-5G would both easily be able to generate the same pressure as a Thunderbolt blower (specs say a max flow of 750cfm and max boost of 14psi for the F and 15psi for the G), and ProCharger's A-1R (450 cfm, 15 psi) would also be comfortably able to meet the T-bolt's needs, while their A-1P (200 cfm, 15 psi) could probably give a decent, if somewhat reduced, bite. If you don't want to work with a centrifugal blower, Paxton makes a wide range of screw-type blowers that easily exceed the T-bolt's requirements (mostly over 1000 cfm and 30 psi), and I'm sure that Eaton would have similar products in their twin-scroll Roots line, but Eaton's website doesn't list flow rates and boost levels.

Alternatively, if you had a powerful enough motor to drive it, you could probably find a Mustang SVT Cobra in a junkyard somewhere that still has a perfectly good blower on it that could be converted at much lower cost than buying a new one.

(The advantage I see in converting an automotive/marine blower is that they're already belt-driven instead of driven directly off the output shaft, meaning that you could probably adapt any handy motor to power it by finding an appropriate pulley to run the belt around.)

EDIT: After consulting with a friend, I found that the Eaton M90 supercharger unit is a twin-scroll Roots blower for automotive applications which is right in its efficiency "butter zone" when it's putting out 250 cfm at 5 psi (in the range that FS specified the Thunderbolt's blower as generating); if you could find a motor that would drive it at about 2150 rpm, you'd be pretty much golden for matching the original unit. Per Wiki, the M90 was used in the 1996-2005 Buick Park Avenue Ultra, 1997.5-2004 Buick Regal GS/GSE/GSX(SLP), 1996-99 Buick Riviera, 2004-5 Chevy Impala SS, 2004-5 Chevy Monte Carlo SS Supercharged/Intimidator SS, 1996-99 Oldsmobile 88 LSS (in limited numbers), 1996-2003 Pontiac Bonneville SSEi, 1997-2003 Pontiac Grand Prix GTP/GTX(SLP), the 2004-2005 Pontiac Grand Prix GTP, the 2006-2007 Pontiac Grand Prix GT, the 1996-2004 Holden Commodore VS/VT/VX/VY, and the 2001-2004 Holden Monaro CV6, if you choose to try the "junkyard" sourcing route.

He also says to note the Lysholm 1200 AX Twin Screw, a screw-type blower with similar output (233 CFM, 5 psi, at 2000 rpm) as an alternative; I point out that it's not going to have the same snarl, however, as the screws wouldn't generate the same pulsing airflow as a Roots.

Only problem is unless you rob a used 4-53 blower off an old detroit diesel the cost of putting an automotive supercharger on the unit would be cost prohibitive. Trying to find an M90 in a junkyard could be a little challenging.

Plus some of those automotive units require an external oil feed like a turbocharger.

Could you possibly somehow use a squirrel cage blower to charge the head?

DJ2226 wrote:Could you possibly somehow use a squirrel cage blower to charge the head?

That's basically what a leaf blower is, an overpowered centrifugal blower. They don't work too well. A positive displacement blower is needed to effectively supercharge a siren. With a regular blower the air will just simply back up and escape from around the fan blades.

Hmm, I didn't know that happens if you just use a shop-vac. That's what I've been using, since I still need an actual blower part for my thunderbolt, as i just have the motor and frame sadly. And it doesn't seem to starve, its been doing a great job, just nowhere near what I would like it to do. So I really would love to get a bank teller pump. Thanks.

-Joshua

Thanks guys for your replies. I am most likely going to go with the bouncy house blower that Jeb suggested. It is within my budget and should work perfect for what I am using it for. From what I have read it puts out 750cfm and draws only about 6 amps. And an extra bonus is that it is yellow less paint work Lol