Finding the right CFM/Engine Size - (and the Metric vs. Imperial thingy)

[77-1201624802]

I am watching the forum for aprox 4 month now and decided to buy the Bruce Plans and register here.

I would like to build a flowbench (with a small budget) to optimize my own modifized cylinderheads ( 3 and 4 cylinder engines with a maximum of 400cc per cylinder / 24.41 cubic inch per cylinder).

The overall power of the whole engine would never exeed 200 hp.

How could I figure out how big my vacuum engines have to be before I start building ?

I assume I can't buy the typical us standard vaccuum engines, since I am having 240V and so I have to buy something in Europe.

Cheers,

Daniel

[thomasvaught-1]

One way to figure the flow requirement.

Using boost logic, ONE POUND OF AIR WILL MAKE 10 HP. One Pound of air is about 14.5 cfm. 14.5 cfm times 20 = 290 cfm required going through an engine at max power.

Tom V.

[williamsmotowerx]

trying to make sense of this thomas.

my engines, single cylinder 40hp

14.5 * 4 = 58cfm

i typically need 200cfm to make 40hp

[DWC]

I think Tom V means cf not cfm.

[Tony]

A simple rough as guts rule of thumb is total (atmospheric) engine induction CFM = Hp x 1.5

200Hp = 300 CFM induction airflow

Exhaust flow CFM = Hp x 2.2

200Hp = 440 CFM exhaust flow

[stevenford]

Add more motors than you need to test at higher pressures

I think people develop heads at 28"-36" but do a turbalance check at 60"-100"

Check out Domel Vs Ametek in Air Movers



Domel, Slovenijan, German motors, 240V

[77-1201624802]

Thanks for the hints.

I have the feeling the the best way will be to go with vacuum motors as they are quite easy to buy (and replace if needed).

I looked around in used-part/exchange parts on ebay and vacuum-repair-stores in Germany, but I am afraid I can't find any bargains, which are vac-motors which are known here or include specs.

Often the vac motors do only have a compatiblity-list (if you want to replace a defect vac), the overal sizes and the watts.

Does anyone have a hint/advice how to get the right vacs or should I just try to get cheap vac motors which are not tiny and give them a try ?

Cheers,

Daniel

[WPH]

[color=#000000]Try to source some central vacuum cleaning motors, I'm using 3 motors at the moment. Mine are dual stage Allaway replacement motors which I ordered via my friends service shop. I think they were around 85eur per piece. Not very cheap but easily available. You might want to check out Clen or K

[COMP]

i hadn't thought about central vac's,,,,i have been looking at wet vac's

[77-1201624802]

Hi,


Central Vacs are quite uncommon in Germany. However I looked around for some industrial vacuum machines for e.g. car washing companies and here we are:
I found several vac motors which have:
metal 14,4 cm (5.6 inch) turbines
1000-1200 watts for 220-240 Volt
3600 liter per minute = 125 cfm
double isolated

Sounds quite nice for aprox 50-60 euros per motor.

[stef-1]

[color=#000000]I used dyson vacuum motors, part # 911934-01. These are YDK YV-2200 motors. Easy to find on ebay and 240v (I'm from UK so had same problem). Six of these should be okay - I paid

[racehead-1]

Ok, let me know the campany that sells these vac. motors in Europe. It is kind of hard to get any industrial vac. motor in Europe, that is why I got mine from he USA.

[77-1212596771]

19 pounds sounds great.

I had to pay a bit more (55 Euro per motor), but they are brand new and with warranty. Just look for dry/wet industrie vac exchange motors (e.g. on Ebay or industry part websites). Most of them will be from Domel, but eventually with an OEM number, so you have to compare the properties of the motor with the Domel-website (See the threads in the Airmovers section).

Daniel

[Moriniman]

[color=#000000][quote="stef-1"]I used dyson vacuum motors, part # 911934-01. These are YDK YV-2200 motors. Easy to find on ebay and 240v (I'm from UK so had same problem). Six of these should be okay - I paid

[77-1212596771]

Then I was even more robbed ( 44 uk pound per domel motor) ?

I looked around a very long time and never found a better deal.

Cheers,

Daniel