4.8 CDS RPM

[Dale]

Hi Guys:

I am quite sure that what HM means by RPM "limits" is that the blower manufacture limits the blower to be run no higher than 3600 RPM. If you give us the front 2 and back 2 pulley sizes we can give you the RPM of the blower when the engine runs at a given RPM.

Also, could someone answer me if the picture RPM electric box can be fitted to a 2000 GM van? I would love to put one of those where a vacuum pull off was.

Thx,
Dale

 

[TimP]

I don't believe that it can. The box connects to the computer port under the dash. The van I have has DBW meaning there is no throttle cable to the engine. You can actually unhook the accelerator and it's connected by quick connect. The box actually increases fuel electronically.

 

[Dale]

Hi Tim:

What year van is your unit that has it, please?

Thx,
Dale

 

[TimP]

2007 van 6.0 extended 1 ton and 2006 cds with salsa.

 

[Matt King]

Call and see what they can do for you. They plug into the diagnostic port for your computer. On mine anyway, the electronic path used is actually the vans a/c wiring. If they don't have anything, (depending on the part) many times you can manipulate a throttle positioning sensor whether you have drive by wire or not. www.offroadengineering.com (200 series perhaps)

 

[Jayson]

After measuring all the pulleys, and finding a online conversion chart I figured the blower speed to be roughly 3,100 rpms give or take 100 due to how deep the belt actually sits into the pulleys.
Here's a rundown on pulley measurements, these are taken from the furthest outside edge of the pulleys.

Crank = 8" ( stock ford pulley used on supercharged F150s )
Electric clutch pulley for PTO driveshaft = 6"
Opposite side of drive shaft pulley = 6"
Blower pulley = 4"

I could be off a lil bit, but either way but changing the size a 1/4 inch hear and there I got between 3,000 and 3200 rpms.

I will say I'm getting killer dry times with a Hydrasonic 1 3/4 wand, 6 flow with a slotted green glide @ 400psi. I'm thinking of taking the flow up a lil more to at least 8 flow.

 

[TimP]

I was under the van yesterday changing the engine oil and was looking at the exhaust. I think that's the problem with the CDS, it looks like 2.5 inch exhaust. If it were 3" I'm sure it would do a good bit better with the vacuum.

 

[Jimmy L]

I rum my cleanco at 1600 rpms and pop the hood open when running.

 

[Rex Tyus]

Why do you pop the hood?

 

[TimP]

I pop mine in the summer sometimes when I finish the job and run the AC to cool the cabin down. Other wise the engine starts to over heat in mine. Other than that it's fine.

 

[Jayson]

I was under the van yesterday changing the engine oil and was looking at the exhaust. I think that's the problem with the CDS, it looks like 2.5 inch exhaust. If it were 3" I'm sure it would do a good bit better with the vacuum.

Mine is all 3"........Intake and Exhaust.

 

[Jimmy L]

Heat rises so I figure open the hood let it out.
I checked some college level text books and conferred with a thermal engineer who agreed with me.

 

[Greenie]

must look like a broken down carpet cleaner?

Ya do what ya gotta do.

 

[packfancjh]

Per Hydramaster the RPMs on the machine shouldn't be any higher than 1500 at full load.

 

[RichardnTn]

1500 rpm to 8" pulley to 6" pulley =2000 rpm
2000 rpm to 4" pulley = 3000 rpms
4005 at 3000 rpm = 278 cfm at 16"hg
4007 at 3000 rpm = 371 cfm at 15"hg

Hope this is right...Richard R

 

[Greenie]

well....according to Richards numbers there should be a nice lil' kick when using 2.5" hose or a Y 50' from the truck with 2" hose.

Not too many out there doing this, anybody gonna give it a try ?

 

[TimP]

Greenie I was planning on it but you said it would be best for the bayco and tank supports so I kinda dropped the idea of the 2.5 hose. Maybe I'll eventually do all 3. If business keeps up like it has been this week, for the rest of the year I may be able to swing it then.

 

[Greenie]

Tim,
My experience was only on the HydraMaster west coast demo rig, and I was all excited to show a few guys at a local CAD day what they could do with a #4 blower TM. Hooked up the 2" Y and frankly I was a little embarrassed and a bit disappointed.
It really wasn't much louder of a rush of air, I even checked the relief valve to make sure all was set at a respectable level. I just scratched my head, I could only conclude that the blower simply wasn't spinning that fast and making much more airflow than the 2" hose could handle.

Now the same set up on a Maxx 470 produced a noticeable difference in airflow on the 2 hoses.

So what would you make of that?

You could always get a $5 plumbing Y and do a quickie duct tape hook up and report back.

 

[Rex Tyus]

Tim,

I have a real y you can borrow if you want to try 4 to the door.

 

[TimP]

Rex I would like to try it to see how it works, it would make the decision a lot easier to decide I have an extra 50 ft of hose anyhow. It's funny cause the max has the same blower as the cds. Maybe the demo you tried was just breaking in? Or maybe you need to turn up the rpms a bit? Or maybe it was set lower than standard, or perhaps it was not set up the same as a final rig? I keep mine set as close to 15 hg as I can get it with a spring and I increased the rpm about 500 or so it's a bit under 1600. I've noticed better dry times by doing the two things especially with the holed greenhorn.