Interesting, and while thats more technical analysis than I have done, running back to back tests, one with an air filter, and one without isn't all that conducive...

It will increase power - for sure, it is allowing the intake to breath easier.
Whether it would even increase power to even offset the weight gain (in real life) of adding the leaf blower in the first place, I am extremely hesitant.

 

Here's a write-up of an electric supercharger:
http://www.turbomagazine.com/tech/0406tur_knight/

Interesting qoute:
"Even a 2.0-liter engine making 15 psi at 8000 rpm required a 30-hp DC motor."

Looks like he runs three Optima batteries to run the electic motor for the blower, and he admits that the alternator can't hope to charge them.

I agree with others, too much evergy conversion going on.

 

Well, a few weeks ago a friend and I did the gas-powered leaf-blower test. I couldn't find this thread so I never got around to posting our dismal results.

The test vehicle was a partially assembled chevy nova II with a 500cid caddy engine, stroked to 570 cid, massive porting, huge valves, crazy lift on the cam but minimal overlap. This engine was built for forced induction (a pair of TD05's), and that part of the project isn't completed. Anyway, it was the test bed.

The leaf blower was a 6 month old Husqvarna 165T, which according to the manual has a 3.6cid engine, produces 4.2HP, 680cfm at the housing exit (530 at the end of the long tube), wizzes at 7500 RPM and can produce up to a 195 mph breeze.

So we removed the long tube and found that the leaf blower just about fit the opening on his throttle body, but was a hair larger so we wrapped the perimeter of the throttle body with duct tape and forcibly wedged the gas blower on, resting the housing of the blower on a block of wood resting on the top of the radiator, then clamped that down using several undersized bungee cords hoping not to have the blower work loose and turn into shrapnel inside the engine compartment.

We did three runs with, and without the gas blower. On the gas blower runs I held the throttle at "full" for the duration of the tests. The blower running full blast with the 570cid idling made a noticable difference in sound, but off idle (1700 rpm or so) I could hear the blower struggling and making odd noises.

Without blower, RWHP, to 4900 RPM.
721HP, 737HP, 725HP.

With blower, RWHP, to 4900 RPM.
730HP, 716HP, 729HP.

There are a lot of variables that can/may have occured during these tests. Speed in which the throttle of the car is ripped, temperature of the engine/coolant/oil/etc, tire traction, dyno age (this is an old, admittedly not so accurate dyno), transmission losses (it has an old, beat up lenco that's easy to shift from 1-2 sometimes, and other times it fights you all the way, so shifting speed may have been an issue), and we had two "runs" with the blower where the blower popped off which I didn't list above as the blower came off.

If you look at the results, while they are a bit wavy from run to run, they are at least very similar/close which tells me that the blower did absolutely nothing of value with it's puny 630cfm. I know the engine is sucking in a lot more than that, probably closer to the 800-850 region at the particular test RPM.

The other thing to keep in mind is turbos and superchargers have extremely tight clearances between the compressor blades and the housing, whereas leaf blowers do not. They are after velocity, not PSI, whereas turbos and superchargers want both.

Would this leaf blower add power to a 1.6L honda engine? I doubt it, but those of you with tiny engines in your ownership are welcomed to try this out and report back your results. 570cid is a lot of displacement and possibly skewed the results to show a zero gain.

Enjoy.

 

^^^That kind of stuff is why I like this site so much.

 

i agree big and he has to be one of the few who will back up his stament with real world test i just wish i had a few neighbors like that..lol

 

if you actualy lived next to fred you would not be saying that.
every time he goes out to do something they all start with the there he goes again routine. ...

just funnin with ya buddy.
how did you make out in the city the other day??

 

The tests weren't planned, or performed here at the house, but instead I met my friend at the shop 3 hours from me, 2 hours from him, so I could help him dial in his EFI system which he was having trouble getting idle to be stable as well as enough enrichment at the 5000 redline. Turned out his tables weren't too far off, but the map sensor wasn't doing it's thing so the GM ECM was guessing and not guessing close enough. Weird that the ECM didn't flag the map sensor as "dysfunctional". Once that got squared away it ran a lot better, and got things "correct enough" for naturally aspirated operation after only three chip burns.

While we were verifying the wiring of the harness (which I made for him about 4 years ago) as well as testing sensors, we were doing the usual "guy thing" BSing about lots of different things and I mentioned this thread, and he said if we get the thing running "reasonably" he'd be happy to help try it out since the car is already strapped on the dyno, and he has the husq leaf blower in his truck - he started a lanscaping/plowing business this year so the blower was "handy" so to speak.

So that's how the tests got started, they weren't planned at all.

We had a lot of problems getting the car on and off the trailer, and on and off the dyno, as the "steering wheel" was a breaker bar (manual rack, steering wheel didn't arrive yet) and there were no brakes whatsoever installed. No calipers, no lines, no master cylinder, no pedal. Like I said before, the car's not close to being finished.

I have to tell you guys though... a 570cid stroked caddy engine sounds wonderful, especially with this custom-ground cam. Negligable overlap so mechanically it idles reasonably well, but the idle will never be buttery smooth since the injectors are of the 120lb variety (sized for the pair of turbos that weren't installed yet) the pulsewidth at idle is so narrow the injectors weren't consistant with their fuel delivery. At 5000 rpm the thing absolutely purred and was beautilful to listen to since there was zero exhaust of any kind. Little flame spurts out of each cylinder aiming right at the fenders, which we took off to avoid baking the fresh burgandy paint.

Other than the block, crank and cam machining (overbore/stroke) my buddy built this engine himself in his garage over the last couple of years. The heads were *seriously* attacked with a carbide cutter where if one were to rotate the heads onto their backs, you'd have eight coffee cup holders. He tig welded a homemade intake which essentially is two aluminum head plates with eight massive tubes going to a 8" round aluminum pipe that he called a "log manifold". The throttle body is also a custom aluminum piece he made, about the size of a small ash tray. His goal with the turbos installed is 1600hp on pump gas. I personally think his 9.2:1 c/r is too high for this but he has another set of rods that will lower the c/r if necessary to about 8:1-ish which is more reasonable for his forced induction power goals. This car as stripped as it is (even with welded doors and a full cage/4link tie in) weighs about 2750lbs with the cad engine/lenco - it's soooooo going to be traction impaired, and if it bites onto the asphalt even for a second the firewall is going to twist and split like a rotting banana in the sun. I like it!

Unfortunately, they decided I was "grossly over technical" and will have to pass for the time being. *sigh*.

 

dang it fred can't you just use bolt on items for a change?

 

I'll run that 1983 Filter Queen (civic)... I'll even give ya 6 cars and what the heck I wont even use the NOS.