I ran an AMR300 supercharger on a fuel injected 420 cc single cylinder Harbor Freight engine with a 1:1 drive ratio. As I recall we got 8 PSi of boost. The 13 hp engine was also ran with the induction pipes disconnected so the blower didn't produce any boost and the little engine had no problem spinning the supercharger up to redline. We discovered a few issues with this type of supercharger, first one was the gear drive inside the supercharger develops a lot of heat and we were able to wick away some of the heat with a water cooled heat sink from a PC. The second issue is the supercharger cannot tolerate any vacuum or negative pressure... like when the engine is at idle. If there is any vacuum, the oil from the gear drive will get past the seals and be consumed by the engine and the gear drive will be sucked dry in a few hours... the solution is to use a bypass or double throttle bodies.

Legend has it, Richard never actually goes home. He just goes on to the next test.

It blows my mind that this channel isn't massive yet. Been following for years, your content is awesome.

The reason you are measuring less pressure with the larger inlets is related to the venturi effect. Although you are pushing more air through the supercharger, you are still using the same funnel where the air intake is and the same restrictor on the exit. The venturi effect is that the pressure decreases as velocity increases. You are flowing more air through the same diameter reductions, and the air pressure at the inlet of the funnel is the same, and the measurement point is the same, so more velocity = lower pressure. If you want a better way to measure it, you should measure the pressure at the entrance to the supercharger (which should be a vacuum at that point) and measure the pressure in your discharge pipe and subtract the two. This will give you the pressure produced by the supercharger only, neglecting the pressure change from the funnel on the input causing the venturi effect.

Air pressure increases about 2% for every 10°f which could explain why the stock fittings produced more boost. Although the higher boost wouldn't produce more power because the mass flow is lower.

Every sub 100hp engine needs two of these.

If Gale Banks taught me anything, it's that the boost pressure is probably lower on the higher flow run as a function of air density. Maybe since the blower could breath easier, in and out, it was able to compress the air more efficiently.

It even sounded better with the bigger inlet and outlet, and the charge temperatures show that it's just the right way to go.

It is just amazing how much you produce interesting content and how much time and effort it must need to do that. Thank you for doing all this!

Very cool test, I remember reading about stuff like this from the 60s where they would dyno one engine running off a SC that was powered by another one. That blower is cute! Don't quite have a project small enough for something like that but it looks like it'd be great for something like a motorcycle, my Cruze 1.4L or a Sprint 3 cylinder.

Listen to those beautiful noises! I now name it The ASMR 500

Boost was higher with the smaller inlet because it was heated more. Going to take your numbers later and generate a lb/min flow rate graph. Thank you for the great work and wonderful data!

Just an idea, you can pretty easily put an optical RPM meter on the blower pulley and compare the RPM ratio between it and the engine to detect slip without needing to go through the change to cog to rule it out.

Air temp is the reason for the boost difference, the smaller adaptors restricted airflow, it created a much hotter discharge temp so the air mass expanded more and that registered a higher pressure measurement.

Mannn you're the best mate!! No one made a test like this. Have a test car with that blower and this info is MARVELOUS! thanks ! 🙏🏼

When i first heard you start the ls with the blower on it, i thought you were just yelling "yaaaaaaaaaaa" for a long time 😂

Great work Richard. Man, I love watching you do stuff hot rod guys like me have always wanted to do.

Very cool data! I think the next step would be to add a MAF sensor in your inlet as well as data for the ambient air parameters such that you can account for air density and measure flow in lbs/min like superchargers and turbos typically are. That will be much more able to be correlated to a HP number. Interesting to see pressure drop after the mods, my thought is that IAT being less means the SC is more efficient, and so is pumping larger mass of air through lower pressure due to improved density. You should get one of those banks gauges, his shit is really dialed in on this whole air density situation.

Man, you really do a great job with your videos, they're alway interesting and fun. Keep up the great work!

I ran one of these on my sweep the floor vw engine and boy did it wake it up! Even at 4 psi it was a huge power increase out of the 1641cc engine. The amr500 is probably the best hp for the money for a vw as long as you can make your own intake adapters like I did although there are a few companies that sell intake kits for these to bolt onto a vw. I've got a few videos of that engine on my channel if you'd like to take a look

Maybe the higher velocity through the modified in/out created some sort of venturi effect across the port going to the boost sensor giving you a false pressure reading? Also it's hard to be sure but it looks like your bigger inlet has the sides of the square maybe protruding out into the round tube... if that is the case maybe you could get a tad more airflow by either disassembling it and grinding those out or else maybe shape one end of the round tube into a square to match the actual opening a bit better like a round to square transition then weld it to a square hole in the plate. I had no idea these things existed till you posted this and man they are cheap, now I got to figure out how to build something with one.

I think some engines that run on poor mixture, I think some skyactiv engine, use the blower to reduce/regulate the air flow and keep the engine in the sweet spot for fuel economy. Cool test.

Amazing work on this! Some things I noticed: Early pulls show the blower belt with alignment wear as evidenced by the white threaded material showing on the edge of the belt 5:53. The blower mounting bracket is being flexed forward under load which you can clearly see at 8:40 if you watch the blower in relation to the engine, letting the blower belt walk on the crank pulley. The belt looks like it rode up onto the outer lip of the crank pulley probably causing slippage (watch the engine crank pulley where the electrical cord in the floor is) you can see the belt was still on the outer lip of the crank pulley when you shut it down. Can't wait for the next video!!

thank you for making this!. i havent even watched this yet but know I will learn a ton!

Dude ,you’re a total stud, I love your attention to detail.

Add some stripes to your drive belt and use an optical tachometer to measure the belt speed. If you plot it vs engine RPM you'll see if the belt slips or not--the engine RPM and belt speed will be linear when not slipping.

Tht was a really cool experiment. I hope you continue testing other blowers just like this.

amazing content! you can tell a couple times the belt walking on the pullys. id also suggest fully welding the exit pipe and a good seal around the mounting metal could be losing boost there.

Love to see the blower content! You should revisit the m90 blower, maybe on a smaller motor like a Honda k series or j series.

Looks like need 4 of those cute blowers 😄

My thought on the difference between flow and boost between inlet and outlet types, making less boost with more flow is that higher flow velocity is naturally lower pressure. So the higher flow number was stacking up less boost - still better for the engine. Steve Brule explains it on Engine Masters better than I can. My estimate is that feeding that 5psi of boost through that engine would make another 132hp(ish) - more than making up for the power draw of the blower

My best guess as to why boost decreased would be turbulence caused. The smaller outlet is closer to the size of the restrictor creating less turbulence on outflow. The larger outlet not only is the air restricted but it's more back pressure against the blower

Have to remember: Your boost pump has same characteristics as wings. Similar restrictions for speed and pressure envelopes as wings. In other words, the compressor can only be spun so fast, and produce so much pressure within a fixed range, or "optimal range". Below and above that speed and pressure, you will see reduced output. OR, as someone else put it, more money = better boost (usually) ;)

Like gale banks says “air density” lower temp air and a little less boost can make more power. That is why the cfm increased

Richard you are a blessing to all of us thank you

This is awesome. Love seeing the "goofy" stuff properly tested.

Before modifying to a toothed belt try modifying the bracket to adapt two pulleys within the belt route one just above the super charger pulley and one just below the supercharger pulley and route the belt through make sure the fit is real tight between the two pulleys, this will ensure the highest contact patch the ribbed belt has around the supercharger pulley itself this will also nearly eliminate pulley slippage at high revs due to the belt loosing grip as the slack end of the belt.

Put a predator engine on the dyno...😂

Great video. I'm looking forward to the next test.

Its awesome to see these videos. Reminds me of the old guys at the track who always thicker and experiment with odd things. Thank you! But i wish you hooked it up to the ls to see the power loss , just for kicks 😂.

Awesome content! I would love to see you do this with a 6-71, with a restriction of say, 8 lbs boost by 6000rpm. So many of us street guys run these, would be amazing to see real world numbers on the horsepower draw. Thanks for all your amazing hot rod science!!

With your inlet wide open, it’s going to take much more HP to spin it, the smaller inlet will require much less hp, Steve Morris did a good test for that..

Very interesting experiment, TYVM! Love your energy & enthusiasm.

You used a longer, ribbed hose for the stock outlet, and a shorter, smooth, and curved hose for the super richie outlet. The longer length and more turbulent flow from the ribs might be the reason for the higher boost. While the Super Richie outlet you have a more "laminar" like flow, less restriction, more CFM, = less pressure/boost at the sensor.

The boost was lower due to the lower temperature. At least 1/2 of your boost was the increased air temperature. Your intakes increased the efficiency of the blower. This lowered the air temperature at the same flow rate. This lowered the boost pressure even though you are moving more air.

More airflow = Less restriction. you get the same result "Porting" (Open up the outlet triangle to the edges of the silencer holes) a Eaton M90 blower or even a MN112 Boost goes down, outlet air temp goes down and WHP goes up. I don't know if the inlet matters as much as the outlet.

Just a spitball guess from my swimming pool building/hydraulic design experience, I think the reduced boost with the 'Super' setup could be from reduced air velocity at the sensor. I know the sensor does not measure air velocity, but with increased air velocity of the factory outlet at the sensor it could possibly measure as higher pressure. A potential way to eliminate the possibility of that would be to run a capped branch flow pipe or a capped T with the sensor in it.

Richard you are a wealth of information sir and i do appreciate everything you do and teach us! Thank you sir and i truly mean it....

I love this... like really LOVE THIS!!!!!

I wonder if you had switched it back to the original smaller inlet and outlets if it would go back to making the same boost. The Amr500 is only rated at 16k rpm so spinning it to 18k might have caused some extra wear and opened up clearances giving less boost.

Very similar to what a friend did with a Benz M63 blower on a Honda, even spinning it backwards it still made boost and needed a FMIC. It was placed where the AC compressor was, AKSC.

Would be cool to do a similar test with a turbo and see how back pressure affects power. Or just restrict the exhaust to cause back pressure. Probably won’t be good data since it won’t have positive pressure in the intake manifold .

Richard thanks for and this and the icing on the cake is you sending it to Kenny Bell wow super cool A+ 10 and a gold star 🤠.Twin AFR-500`S on the Trophy 4 banger would look cool

The smaller outlet would restrict it more I bet if you put big inlet with stock outlet boast would go up in my opinion

Awesome video and information! I'm guessing the drop has something to do with that restrictive tube you selected and Bernoulli's principal where increased flow gives you decreased pressure 🤔

Dude I love your channel I watch ur videos religiously I think that u and gale banks need to team up I think you two could do great things together to educate the gear head world

The AMR500 blower could about perfect fitted to a 350 to 500 CC 4-stroke motorcycle engine!

Great content, I was hoping to see how much power that little blower made.

as for the curve flattening out at the top (18k rpm) my uneducated guess would be given the size of the rotors in that little guy is that the vacuum on the intake side is so strong that it is not pulling more air in anymore effectively. its just stretching air the same way a engine does on the intake side. not belt slippage

Excellent view Richard of HP to make boost. NO WONDER TURBOS are so popular & Super Richey Dyno really made it all click for me.

I think the lower temp made up for the horsepower that would have been lost from the lower amount of boost lower temperature air is more dense which means more horsepower

You should test this on various combinations. A ford 300 i6, a 4 cylinder of some sort, obviously the LS.

I like the Demeuse pulley you have there. Im friends with Tom on FB. Met him at a car show a couple years ago. His LS supercharged Sonoma is SICK.

Love these videos Richard when your doing it😁👍💪

You need to put it on the Pontiac 4 cyl. Also, did you retest the output in the first configuration to make sure to it hadn't warn which would have reduced it's efficiency?

"Do you think it was slipping?" Gee, I wonder how it wandered between crank pulley grooves.....

You got less boost on the restricted runs with the larger intake specifically because your air density was higher, as proven by the lower temps. the mass flow rate was probably higher too, but for the same mass flow rate the parasitic loss was lower. overall that was a notable improvement to go with the larger inlet, good stuff!

Was a great video, though kind of disappointed you didn't hook it up to see if it'd make power gains on the ls, cause why not 😂 love your videos and have learned A LOT through them on my journey to building my boosted 5.3L

I think you were getting more airflow with less boost pressure on the improved intake due to it running more efficiently. Perhaps because the stock inlet was a restriction, causing you too superheat the air, or perhaps due to shape of the inlet (curves instead of right angle edges etc).

More flow through a bigger opening is going to give you less pressure…

Air flow and air pressure are inversely related. Adding better flowing inlet/outlets reduces inherent restriction. This increases air flow (cfm) while simultaneously reducing pressure (psi) which is just a measurement of restriction.

I'd like to see it hooked up before anything is done to it. I have ideas about the boost discrepancy, but believe I'll keep that to myself because I'm probably incorrect.

they work for air cooled vws

I'm sure there was some belt slippage. Also, it may have been outside its efficiency island. That said, it made some nice noises. 😎

WOW...this is probably your best work as an automotive journalist.

Hot air expands, with the hotter air created by the stock inlet/outlets, there is more airflow in the outlet pipe to give you higher boost but that air is less dense. If you measured the airflow after the blower this would have shown this The lower boost setup has a lot denser air, therefore more oxygen, and could produce more power.

I was on the edge of my seat until it didn’t make boost until the ls “Que the price is right loser sound” lol

I’m only about an hour from you. I need help just getting my turbo to line up. 😂

On my supercharged LS I've increased header primarily from 1 3/4 -> 1 7/8 and lost 2psi boost. Port matched some constrictive port adapters and that Increased airflow made it lose about 2psi again. Larger intake tube and TB, Saw less boost. Superchargers like the free airflow and you get less boost, less IAT, and more airflow.

It was a great video showing these little motor awakeners. I've seen them used on Geo Metro cars, Honda Civics, plus many more brands overseas mainly. Should support up to a 3.5L with boost till 4500rpm (222cfm). I believe air dynamics changes quite a bit when you have an engine sucking on the outlet of the AMR. Would like to see some real use. Thank you Richard for the time you spend on these ideas!!!

The bigger inlet allowed more turbulence on top of the blower where it’s picked up. The bigger inlet can make more flow with the bigger inlet but when you restrict to add boost it creates the turbulence which equates to less boost. You basically reached the max boost capacity of the the case. Just my hypothesis. Edit: you may be able to fix the turbulence and keep the bigger inlet by shaping the inlet slightly to keep the over all diameter but allow for less turbulence. Maybe 😂

What if you put an optical tachometer on the blower pulley? It sounds like its slipping to me. The flow is surprising but so is the horsepower needed to spin it. I'm thinking it would take a 60hp motor to around 100hp on 8-10psi with good charge cooling.

I think the blower overheats at high speed, it causes all sorts of extra friction and would eventually show as belt slippage. I doubt you can just keep spinning the little guy forever, something eventually has to give. As to the increased flow causing less boost, my guess is the extra airflow increasing velocity and then pressure drop over your map sensor. That, and it seems the outlet would be much cooler with the extra airflow. I'd be interested in retesting with an "intake manifold" with much more volume.

The higher boost pressure on the restricted nozzle is just from heating (inefficiency). The high flow nozzles are less restrictive and result in less heating of the intake charge, thus lower indicated boost.

Was curious about these blowers. They look like the units in small sewer treatment plants. It would be nice to see what it does with a stock subaru 2.0 or 2.5.

So, my question is how MANY AMR500 blowers can you fit on a single engine? /s

Looking at the higher boost on stock inlet/outlets, I wonder how much extra length and turbulence from a radiator hose that wasn’t smooth on the inside caused?

Just a thought, my thinking is if there's more airflow because there is less restriction which in turn would also lower boost,maybe a bigger blower could make up the difference. I don't think the little blower has enough "ASS" to make up the difference. Hope that makes sense lol Love your videos man!

Passing the point of diminishing returns maybe with the drop In boost? I'll give it one thing, it sounds damn good. Richard, now you need to hook it up to the engine so we can see how it becomes a restriction 😆

Now you need a 3 cyl Geo Metro engine to put it on!

Awesome Information!!!! thanks Richard.

Hey Richard, I have seen air loss by backfeed thru the SC seals. Hot air expands the seals, cool air shrinks the seals. Just thinking. Efficiency inside the unit might be geared towards small CI motors. Say 4 cylinder motors. Just a thought. Interested what KB comes back with. 👀

Lol love the mount bracket easy peasy

That cute little thing could be cool if made to work on something like a motorcycle engine.

Supercharged 3800 guys learned long ago better flow = less boost. But it lowers intake temps and allows for a pulley change to make more power without spark knock.

I think the reason the boost went down with the bigger inlet and outlet is because the smaller outlet was an additional restriction. When it went away the boost dropped. The boost droppinig off at the top looks like choked inlet flow.

I think the blower lobes are actually separating. I don’t think the housing or the gaps inside the housing between the lobes are holding any more pressure.

Still think you should stick it on a 4cyl 2.3l engine

Great job as usual!

Awesome actual testing