Ported MM'd BR600

[xtremez]

So I was doing some fall clean up in the yard today when I started thinking about this crazy idea. Done right , I could do all my leaf clean up from my front porch. Anybody every try this?

 

[bryanr2]

bsnelling did his Shindaiwa (802?- if memeory serves me right) backpack blower. Did an awesome thread on it with videos. Was impressive.

 

[sawfun9]

I'm not sure the 4-mix engine would respond well to the mods that a two stroke does. I just got a new BR600 and love it, I had been using a Shinny 24cc handheld but the BR600 seems to have more power at idle than the Shinny did at half throttle. I wouldn't mod the muffler on mine since it's so nice and quiet. Unlike a saw that varies in rpm, blowers are usually kept at the max rpm for long time periods, and the noise would become a problem for me.
At some point rpm limits, blower speed, and cfm capacity would be maxed out and more power might not be beneficial. Kinda like jet boats, at some point more power doesn't yield better results.

 

[XSKIER]

That's not a blower. This is a blower.
http://youtu.be/JO3ymqfPrxA

 

[XSKIER]

Sawfun,
The only thing that will load my km130 to below the electronic rev limiter is the ht saw buried in hardwood. It seems to me that the rev limiter would be the limiting factor in 4-MIX modification.

 

[KenJax Tree]

Get one of the blowers they use at race tracks (NASCAR) they use jet engines.

 

[ChainsawmanXX]

I know some other things that blow... but. Ill keep it clean

 

[xtremez]

I'm not sure the 4-mix engine would respond well to the mods that a two stroke does. I just got a new BR600 and love it, I had been using a Shinny 24cc handheld but the BR600 seems to have more power at idle than the Shinny did at half throttle. I wouldn't mod the muffler on mine since it's so nice and quiet. Unlike a saw that varies in rpm, blowers are usually kept at the max rpm for long time periods, and the noise would become a problem for me.
At some point rpm limits, blower speed, and cfm capacity would be maxed out and more power might not be beneficial. Kinda like jet boats, at some point more power doesn't yield better results.

I was thinking that would be a factor of more power but no extra velocity. Eh, it was just a thought

 

[xtremez]

bsnelling did his Shindaiwa (802?- if memeory serves me right) backpack blower. Did an awesome thread on it with videos. Was impressive.

I'll have to hit the search box and look for that thread. Thanks for the heads up

 

[sawfun9]

Well one way around rpm limits is an overdrive transmission. I ran one on my fuel pump on my old race car. It's a bit over the top, but if you have the torque to pull it it would work. And it's not the big or heavy.

As for jet engines, I think they not only blow they torch things up a bit as well. I remember them at the dragstip more than a few times here in the PNW where we do get quite a few rainouts. If you could burn the leaves up before they blow away you'd really have a system with little cleanup (EPA ouch). Otherwise flying burning debris might make your life a bit more challenging

 

[xtremez]

Well one way around rpm limits is an overdrive transmission. I ran one on my fuel pump on my old race car. It's a bit over the top, but if you have the torque to pull it it would work. And it's not the big or heavy.

As for jet engines, I think they not only blow they torch things up a bit as well. I remember them at the dragstip more than a few times here in the PNW where we do get quite a few rainouts. If you could burn the leaves up before they blow away you'd really have a system with little cleanup (EPA ouch). Otherwise flying burning debris might make your life a bit more challenging[/QUOTE


I'm a trained fire fighter. Does that mean I can blow burning leaves around and call it fire training? Relax folks, this is just a test.

 

[sawfun9]

Well you could justify the jet engine expenditure that way I guess. kinda like justifying a new saw you don't need. and if that turbine was hooked up to a saw that would kill two birds with one stone. Hey now there's an idea, a Kombi powered by a turbine. Might get a bit hot though. And that coming form a guy that has burned holes in his chaps form carrying a ported 880 to close.

Back to the original subject, you could supercharge the 4-mix and see how that works. You might try using nitrous or the air the blower makes. Getting the mix right and holding the thing together would be more than a bit tricky i'd imagine.

 

[xtremez]

Well you could justify the jet engine expenditure that way I guess. kinda like justifying a new saw you don't need. and if that turbine was hooked up to a saw that would kill two birds with one stone. Hey now there's an idea, a Kombi powered by a turbine. Might get a bit hot though. And that coming form a guy that has burned holes in his chaps form carrying a ported 880 to close.

Back to the original subject, you could supercharge the 4-mix and see how that works. You might try using nitrous or the air the blower makes. Getting the mix right and holding the thing together would be more than a bit tricky i'd imagine.

Hey if all else fails ill just slap on a Holley double pumper with custom header, high rise intake, twin turbo, fuel injected with a 500 HP shot of NOS. Stihl Timber Sports here I come!!!

 

[blsnelling]

What I did to my blower will have little to nothing to do with you're BR600. You're not dealing with a 2-stroke. You have a cam operated intake and exhaust valve. Totally different ball of wax. To change intake and exhaust duration would require a different cam. To change intake and exhaust area would require larger valves. You might be able to open up the intake and exhaust runners, but I wouldn't waste my time. You might investigate a MM, but that's all I'd do.

 

[Tempestv]

Well one way around rpm limits is an overdrive transmission. I ran one on my fuel pump on my old race car. It's a bit over the top, but if you have the torque to pull it it would work. And it's not the big or heavy.

Then there is the bloodhound landspeed record attempt car, which uses a formula 1 engine to power the fuel pump for the jet engines...

 

[xtremez]

What I did to my blower will have little to nothing to do with you're BR600. You're not dealing with a 2-stroke. You have a cam operated intake and exhaust valve. Totally different ball of wax. To change intake and exhaust duration would require a different cam. To change intake and exhaust area would require larger valves. You might be able to open up the intake and exhaust runners, but I wouldn't waste my time. You might investigate a MM, but that's all I'd do.

I'll scout around for an xtra muffler and break out the brazing torch and do some experimenting.

 

[user 64030]

You can drastically improve the flow characteristics of the runners in a 4-stroke, by modifying the short-side radius, doing some bowl-blending and increasing the overall section/size of the runners. Never lower the floor of an intake runner in a 4-stroke it reduces intake velocity.

Short side radius is the curve the runner makes as leaves the cylinder the tighter of the 2 curves in the runner
Bowl Blending refers to the "bowl" or the pocket machined/cast in for the valve. If you look at the head w/out the vale the bowl would be the portion of the runner that is round blend this area where it transitions to the port as they are typically not a smooth transition.

Never seen the IPL for a BR600 so if the head does not come off the engine or if it is a flat head design (like a Briggs) there is not a lot that can be done.

It is a lot of work and once you max out the blower turbine your wasting energy fuel anyway....

You may have netter results looking at making the turbine flow more CFM at the same RPM, either w. bigger turbine of??? Maybe adapt a Turbo-charger off a Semi (any semi salvage yards around?).

dw