Red rooster

Guys,
If you do the summs on the fan size it doesnt work ! Some really big diesel motors ( earth mover size ) use an electric supercharger to kick the motors turbo into life .
Some smart marketing guys then started trying to sell electric superchargers to car owners ! Problem was you need a 20bhp motor to do a lot .
Where do you put the 200lb motor ?
Maybe a 964 Hybrid !! with the trunk full of batteries .

All the best

Geoff

JasonAndreas

I know Borg-Warner has an electric supercharger sitting on the shelf waiting for someone to switch to 42v which apparently is never going to happen because of the added cost.

Red rooster

Jason,
That Borg Warner design is really neat. That 42volt fiasco threw a load of R&D down the toilet . All the 42v vehicle control systems for steering/lighting etc,etc.
The supercharger thing always was a load dependent , transient bhp improvement. To get more real power the supercharger has to move a big volume of air which takes a load of power.Shame that the basic laws of physics stand in the way !!

All the best

Geoff

jjbunn

So what I don't understand is how people like K&N can claim significant BHP improvements (double digit?) by using their filter instead of stock, and yet the fan people can only muster around 10 BHP extra with a power-voracious electric fan (800 Watts - and their blurb makes this sound like an advantage!) actually blowing the air in at high pressure. Something doesn't add up, or maybe I have misunderstood?

Smokin

Seems to me that the fan would only inrease drag and reduce flow into the intake runner. That is a lot of air to push.

JasonAndreas

Marketing always trumps science! An 800 watt fan will generate 1.07HP but if the blades from that fan are blocking the intake manifold you will lose HP.

NineMeister

Simply because a 3.6 litre engine running at 6000rpm at peak power with 100% volumetric efficiency will shift

3.6 x 0.5 (fills ezch cyl once per 2 revs) x 6000/60 (rps) = 180 litres/s

which is approximately 380cfm. Therefore to generate a significant increase in performance you would need an electric fan that would supply 500cfm at a pressure ratio of 1.25 which needs an awfully big fan. As a comparison I believe that Paul Frere quotes the 911 cooling fan moving just 11 litres/s (23cfm).

Now, if we accept that the engine is consuming 380cfm and the cooling fan 23cfm at peak power, and that the engine bay contains maybe 2.5 cuft of free space, the intake air is replenished about 400/2.5 = 160 times per minute. This equates to new air being available in the engine bay 2.7 times every second, which now begs the question of how much can the intake air warm up in 0.375 seconds?

Cold air intake systems like this are definitely an advantage for town driving but flat out, on a dyno or on track they will make no difference - which is why I suggested that the 90 degree bend is more important than the temperature.

jjbunn

Excellent: real numbers that make sense! Thanks, Colin.

aeroman

If you really want to increase flow all you need to do is make a bump on one side of the intake tube. The bump will cause the air going in to swirl and flow will increase.

Imagine holding a bottle of water upside down letting the water drain out. It chugs and burbles as it comes out. Now do that again but move the bottle in a circular motion and watch how the water comes out much faster and does not chug and burble.

I work in aviation. The company that I used to work for had several performance improving products on Rusty Wallace's learjet. The owner of the company and Rusty are friends. Rusty once approached the owner about improving the performance of his race car. The owner came up with 3 items that would invisably from the outside improve the performance. Rusty got away with it for 3 races before a post race inspection found them. All 3 items are now on the banned list by Nascar. The bump in the intake tube was one of them.

Red rooster

Colin,
Good numbers but your conclusion is at odds with your explanation !
I would be happier with a conclusion that the cone filter will be affected by localised intake air heating around town( low rpm/load-air consumption ) and most effective at WOT , high revs.
Good to chew this stuff as light relief!!

All the best

Geoff

NineMeister

I think we agree Geoff, it's just that I was not specific enough with my grammar. What I meant was that relocating the filter to under the spoiler and protecting it from engine heat (cold air mod) will make a difference around town, whereas flat out the heat protection would makes no difference - but the elbow would.

Red rooster

Colin ,
Agreed !

Geoff

wsybert

i do remember a post with temps.. can't remember who posted... but, showed that while idling or slow moving, there was more heat. While moving at speed, there was no difference between under the spoiler or back under the rear of the engine.
I would assume that the spoiler would evacuate most, if not all of the hot air from back under the engine, at speed.
I do appreciate all the input...
I looked into the electric fan mod, but figured that if it was really that good, everybody would be doing it. Couldn't see an electric fan flowing enough air... guess I was right.

N51

Bill,

I apologize for taking your thread and excellent work on a highjack. I posted the electricsupercharger site as a joke reply to jjbunn's question, believing such things had long ago been debunked on other forums. Never did I think anyone here would take it seriously.
Sorry for the detour.

Best,
Noah

jjbunn

I don't know about others, but I really enjoy these little detours :-)

I have an idea for a post that will generate the most thread traffic of all time: suggest that removing the drip tray and fashioning it into a heat shield with ducts to carry the under-spoiler grille air into the air pipe might be a good way to gain a couple of BHP