Intake Fans / Power Adders

Mudgey · Post by **Mudgey** » Mon Jul 22, 2013 10:59 am

I saw some of these ebay intake fans and after seeing the power draw and CFm output I thought there is absolutely no way they can make a difference, my engine breathes about 500cfm with the supercharger.. infact the fans in my lightweight race car heater systems are more powerful! Anybody had a play with these before?

So it got me thinking and I was wondering if you could actually make some power, i then came across leaf blowers with people hooking them up to the intake, I saw some people gaining 10hp and 16 ftlb of torque.

In my catalogue I can get two twin fan centrifugal blowers with a combined output of 2400cfm from 60amps of power draw. I worked out a spread sheet and my blower has a compression ratio of approx 1.54:1, so if I can make 1psi pre supercharger I get 1.54 on the other side. The fans can blow approx 4.5x the flow of the engine so i think there is room to increase pressure a bit.

The only way I can check this would work is by using a Ventury to exhaust the approximate amount of cfm the engine draws naturally and then measure the pressure in the plenum chamber between the fans and the throttle body. Do you guys think it would be better to run the fans in parallel or series? I feel we would get less airflow in series but a higher pressure. I think there could be some good gains to be had as the std throttle body on the SC k20 becomes a bottle kneck at the upper rpms.

Anybody ever played around with this?

Post by **DaveyBa8** » Mon Jul 22, 2013 11:06 am

There great when they break up and jam into your valves

Post by **rob quilter** » Mon Jul 22, 2013 11:07 am

They don't do anything from what I've seen.

Check out this video where they fit one and dyno it, they also fit leaf flowers too.

[youtube]cbGWgvJN1_8[/youtube]

Mudgey · Post by **Mudgey** » Mon Jul 22, 2013 11:14 am

This is what I can't understand, there are people selling units online that do 130cfm, draw 10 amps and are charging £175!!

I think 2400cfm's for 60amps might actually do something, there is enough airflow there to hopefully produce some a positive pressure difference, I forgot to mention the 500cfm airflow is the max the engine will ever consume at full chat, so at 4000rpm the engine only consumes 250cfm. I think it will be fun to try anyway!

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Mon Jul 22, 2013 6:55 pm

"Ben's concerned the car might make too much power, so he's fitting extra straps"

Mind you, 32bhp and 1 wheel drive? That thing must have been a total beast, before they even started tuning it!

(I'm seriously impressed by a turbo that spins at 100,000 times as a second though

)

kris_aka_edu · Post by **kris_aka_edu** » Mon Jul 22, 2013 7:00 pm

Don't laugh but I actually put one of these on my astra 1.8 convertible, it actually made decent noticeable diference. However it completely messed up the idle and kept idling up and down.

Post by **RattyMcClelland** » Mon Jul 22, 2013 8:01 pm

Problem with these fans is that they dont compress air and create pressure.

Its pressure that you need. No amount of cfm from a fan will create enough pressure to create boost.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Mon Jul 22, 2013 8:23 pm

And even if they did, the standard engine management wouldn't be able to cope with anything much above what it would normally get at speed on a cold day, so you'd just end up running with a lean mixture?