Supercharged 5hp Briggs Setup!

#1
First Test Video- [video=youtube;q7SShzrW7Ro]https://www.youtube.com/watch?v=q7SShzrW7Ro[/video]

Right now its making about 5-6psi which is exactly where I want to be! Its still runnig a little on the rich side, but im gonna make some adjustments and hopefully get a test ride video soon!

Link to the first video- [video=youtube;JOf1-i5Qo88]https://www.youtube.com/watch?v=JOf1-i5Qo88&t=8s[/video]
Today I’m working on something quite interesting, supercharging my minibike 5 horse Briggs, it’s been tried before with failure mostly, but I am determined, even if it blows this motor up!

I deleted the vacuum pump off of my 6.5 Turbo Diesel a while back, but I held onto it thinking it may come in handy some day, and my crazy mind decided one day I was gonna turn it into a supercharger! In this video here I talk about how I plan on running it (THIS IS SUBJECT TO CHANGE) and I also hookup the pump to a drill to get some pressure readings! Current plans are a 1:1.4 drive ratio, should get me about 4600-4900 blower rpm with the engine wide open. I ordered a 3-1/2” drive pulley and will use a 2-1/2” driven pulley that came off the original mini bike engine! I also pulley the pump apart, drained out the old oil, and replaced with 5w-30 synthetic, hopefully it helps the pump hold up to the higher rpm!

As of right now I’m planning on running a blow thru setup, I am going to experiment with a pull thru setup but I’m afraid the gas/diesel will eat through the diaphragm inside the pump. Any suggestions are appreciated just don’t be an Ass!

I’m mainly looking for better hill climbing and trail riding capabilities, but I’ll see how much speed I can get out of this setup as well! It’s a work in progress that will most likely span several videos.

Link to my minibike video- [video=youtube;-_g3L5UDb9o]https://www.youtube.com/watch?v=-_g3L5UDb9o&t=1s[/video]
 
#4
Blowers seem to fair a lot better than turbos on single cyl engines. Smart to keep the boost low. I would get a more robust mounting setup for the blower to keep the belt tighter. Couple new or ceramic bearings in that pump might help as well. Takes HP to spin it, if you can make it easier to spin that frees up HP
 
#5
Lets just say I like my lower half being intact lol! Once I get my hands on a welder I plan on making a custom mount for it so the belt runs straight and tight. There isnt really any way to get to the bearings on this pump without hacking it up, I did replace the old dirty oil with 5w-30 synthetic though hopefully it helps reduce the drag a bit
 
#7
I remember when I was a kid they use to sell a super charger for the brigs raptor engine that looked like a roots type blower. Don't know how well it worked but remember wanting one for my go-kart. Wish some one would reproduce them or make a new kit for these and the honda motors.
 
#9
Ya this was close to 20 years ago the last time I seen one advertised. Don't know the brand or how much power they made. Just remember they were painted black and said they were for the Raptor 2 motors.
 

65ShelbyClone

Well-Known Member
#12
Hansen superchargers are the only ones I know of that were actual kits. They were bulky and complex though; the blower mounted in front of the engine and long plumbing connected it to a big funnel-shaped plenum.

There are other options these days....
 
#13
There are Aisin superchargers for reasonable prices on eBay... These are used in things like Subaru, Toyota, and others, but in the overseas market. The 300 is a small unit that would work well on the smaller OVH clones, the 500 is bigger and would sized about right foe a big block.

I have one of each and intentions to do something with at least one of them. Small engines for minis and karts need a plenum... I'm thinking that the hose between the output and the intake could serve this purpose if it were long enough, but I do not know this for sure. If anyone who has experimented with blowers cared to share any experiences, info, or multiplier for figuring the plenum volume, I'd be all ears.
 
#14
Have you guys really thought about the way a governed engine works? Under acceleration, the throttle is about half way open, and it goes to about quarter throttle when the governor pulls it back. At wide open throttle, manifold pressure might get close to atmospheric pressure. As you get up to speed, the throttle starts to close and therefore, limit the RPM. Intake manifold vacuum and crankshaft load are the major limiting factors on gas engine RPM. If you pressurize the intake manifold, you will need some serious load on the crank or you will splatter the engine immediately.
If I may make a suggestion, run the blower off the rear wheel.
 

65ShelbyClone

Well-Known Member
#15
I don't think anyone proposed supercharging a governed engine. If a roots blower is run off the axle, how will the engine get air when stationary? How would boost be controlled as speed increased?

There are Aisin superchargers for reasonable prices on eBay... These are used in things like Subaru, Toyota, and others, but in the overseas market. The 300 is a small unit that would work well on the smaller OVH clones, the 500 is bigger and would sized about right foe a big block.

I have one of each and intentions to do something with at least one of them. Small engines for minis and karts need a plenum... I'm thinking that the hose between the output and the intake could serve this purpose if it were long enough, but I do not know this for sure. If anyone who has experimented with blowers cared to share any experiences, info, or multiplier for figuring the plenum volume, I'd be all ears.
That's a 500 in my picture. It's a little oversized for the GX140 it's sitting on. ;)

It's hard to make a plenum that's actually too big because it would be huge and tough to fit anywhere. Multi-cylinder engines usually do well with a plenum volume at least twice engine displacement. With a 200cc single I would shoot for 700-1000cc.
 
#16
I don't think anyone proposed supercharging a governed engine. If a roots blower is run off the axle, how will the engine get air when stationary? How would boost be controlled as speed increased?
I agree, there wouldn't be any point in supercharging a governed engine, or spinning off the axle. Besides the issues involved with that, the main advantage of a roots blower is the instant boost available. It has to be engine-driven for that.

a 500 in my picture. It's a little oversized for the GX140 it's sitting on. ;)

It's hard to make a plenum that's actually too big because it would be huge and tough to fit anywhere. Multi-cylinder engines usually do well with a plenum volume at least twice engine displacement. With a 200cc single I would shoot for 700-1000cc.
Yeah, just a little over! But... I wonder how far you could get by underdriving the SC in a situation like that? There has to be a limit I'm sure. The 300 would definitely be the way to go for a small block.

Which, here are pics of a 300 and a 500 side by side with a quarter for perspective, for anyone interested (300 on left, 500 on right):

IMG_9248.jpg

IMG_9249.jpg
 
#17
I agree, there wouldn't be any point in supercharging a governed engine, or spinning off the axle. Besides the issues involved with that, the main advantage of a roots blower is the instant boost available. It has to be engine-driven for that.



Yeah, just a little over! But... I wonder how far you could get by underdriving the SC in a situation like that? There has to be a limit I'm sure. The 300 would definitely be the way to go for a small block.

Which, here are pics of a 300 and a 500 side by side with a quarter for perspective, for anyone interested (300 on left, 500 on right):

View attachment 237782

View attachment 237783
I'm trying to restrain myself here but can I still get them, where can I get them, and how much do they cost?
 

delray

Well-Known Member
#18
I would think when you start to making some real boost in one of these little guys you would maybe need to machine a fire ring.
 
#20
I'm trying to restrain myself here but can I still get them, where can I get them, and how much do they cost?
You can get the 500 in the $212 range, refurbished. Didn't see any 300's just now, but be aware they generally cost a little more than the 500's do when you can get them. Do a search for "aisin supercharger", or "aisin am500" or "aisin am300", or similar.

AM500 link:
Aisin blower
 

Top