Two carb intake setup

[dwilfong]

I was doing some surfing on the web and cam across a patent for a two intake system on a two stroke eng.

My buddy Eric told me about a two intake K-90 he had one of only a few made. Have not had the pleasure of checking it out yet but maybe he will show it to me If I bug him enough.

So I had a brain storm. :blink:

I have bin messing with a 24/7 eng set up and was now thinking if you added a separate small carb to the eng that would only open at 3/4 throttle. kinda like the secondaries on a 4 barrel car eng.

that you could have the low end power but when the eng got up on the pipe the second carb would kick in by passing the intake disk or valve setup.

Could be put right in the boost passage to take advantage of the pipe draw.

Kinda like a strait shot port .

Dam I will have to try this.

 

[shawdaddy]

I have seen this K motor run in the past and it was a SCREAMER!!!

 

[NITROSNIFER]

Al Hobbs was running one Sunday. Sounds great and yes she was a screamer.

 

[dwilfong]

So let me ask this is that eng set up as I have described in my brain storm?

Any one want to share some pics?

Already measured up the RS 1.01 and it looks doable with a .350 add on carb.

 

[Duck899]

Al Hobbs was running one Sunday. Sounds great and yes she was a screamer.

Pictures are worth a thousand words, think of all the typing you could save.

 

[Al Hobbs]

There is one carb on this K90 intake. There are two passages in this K90 rotor. It provides more fuel into the engine for each revolution.

Kalistratov showed Andy Brown and me his idea shortly before he died. He only produced a few of them. But, they are no secret, especially in Europe. As it requires a special mould to produce the rotor, it raises the price. That is one reason why you don't see them on other engine brands.

I've run this particular K90 engine off and on for several years. It seems to be more difficult to find a needle than with the standard rotor.

I think for an engine to be a consistent performer, it is best to keep everything simple. To be a popular engine, it is best to keep the cost reasonable.

Al Hobbs

 

[dwilfong]

http://www.google.com/patents/US6216650

Here is a link to what sparked my interest.

This was summited by Zenoha.

This was a off shoot of a project started by Gordon Blair in 1979.

http://www.google.com/patents/US4253433

Also look at this. two carb set up with direct ports to the cylinder.

http://www.google.com/patents/US6644251

Think of a 3 carb set up with a carb for each port in the cylinder that only open up at full throttle. and one carb in the traditional manner to start and run at low speed

The top end would only be limited by the mechanical limits of the rotating assembly.

 

[Andy Greene]

The top end would only be limited by the mechanical limits of the rotating assembly.

A line your all too familiar with crossing

 

[Tom Foley]

The top end would only be limited by the mechanical limits of the rotating assembly.

A line your all too familiar with crossing

:lol: :lol: :lol: :lol:

 

[dwilfong]

go a head yuck it up!!!!!!!!!!!

Have not broke any thing since I got theses new pistons.

got to try it just looks too cool not to.

Two barrel carb on a CMB 1.01 why not?

Got it all in my head just waiting to explode. :wacko:

Just think about it when the secondary kicks in and it spools over the top

Here is a carb.

http://www.google.co...tents/US7104253

 

[Michael Caruso]

go a head yuck it up!!!!!!!!!!!

Have not broke any thing since I got theses new pistons.

got to try it just looks too cool not to.

Two barrel carb on a CMB 1.01 why not?

Got it all in my head just waiting to explode. :wacko:

Just think about it when the secondary kicks in and it spools over the top

Just like any IC engines as with our little ones you can get the carb area too large easy. Based on engine displacement, port area and rotor timing just the intake side. Good luck I hope you find a better combination than you have now.

 

[dwilfong]

Ok back to thinking out loud.

Looking at the 3rd example thy use two carbs and two different intake systems with a reed at the end of each port.

This is with a non piped eng where the reed would have to be used.

With no pipe to take control of the eng the intake dose all the work.

Now on a piped eng at some point the pipe takes control of the eng. Then the secondary port system would come into play.

this would solve some of the problems with a open intake eng.

Two different intake tracks to work at different times in the power band.

Running the primary carb to wide open before engaging the secondary carb would make tuning simpler with two different needles.

Tune the eng first with the primary carb and set the needle then open the secondary and do the final tune.

Wonder if this has ever bin explored?

 

[dwilfong]

go a head yuck it up!!!!!!!!!!!

Have not broke any thing since I got theses new pistons.

got to try it just looks too cool not to.

Two barrel carb on a CMB 1.01 why not?

Got it all in my head just waiting to explode. :wacko:

Just think about it when the secondary kicks in and it spools over the top

Just like any IC engines as with our little ones you can get the carb area too large easy. Based on engine displacement, port area and rotor timing just the intake side. Good luck I hope you find a better combination than you have now.

I have bin making larger carbs for my 1.01 and have not found to large of a carb yet. the problem is the window on this eng is to small for the size of the eng to produce its maximum power.

Opening up the ports takes this eng to a higher level but the intake is the choke in the system.

The oval boar carb I run now fills the window and is only equal to a .580 round carb.

The program I use calculates at least a .650 to a .750 carb is needed to operate at 28000.

Now if the eng will hold up to higher RPM a much larger carb will be needed.

A second intake track is the only way to feed this much air.

Do not know if you don't try.

 

[Tim_Duggan]

The program I use calculates at least a .650 to a .750 carb is needed to operate at 28000.

Now if the eng will hold up to higher RPM a much larger carb will be needed.

A second intake track is the only way to feed this much air.

Do not know if you don't try.

A friend spent a lot of time (and dollars!) pushing the RS91/101 to high rpm ranges and had some spectacular failures occur. I suspect some sort of harmonic type problems are coming to the fore once the rpm's get up there, as things like the steel carb needle would break off and get injested, things shaking themselves apart, crankpins shattering etc. etc. I suspect you would have to really look into the crankshaft / rod area in terms of distortion /deflection and reciprocating weight balance % if you are going to chase more rpm or it's just going to grenade, regardless of the induction type.

 

[Tom Foley]

go a head yuck it up!!!!!!!!!!!

Have not broke any thing since I got theses new pistons.

got to try it just looks too cool not to.

Two barrel carb on a CMB 1.01 why not?

Got it all in my head just waiting to explode. :wacko:

Just think about it when the secondary kicks in and it spools over the top

Here is a carb.

http://www.google.co...tents/US7104253

Only kidding man , you never know till you try !! :lol:

 

[Michael Costanzo]

http://www.google.co...tents/US6216650

Here is a link to what sparked my interest.

This was summited by Zenoha.

This was a off shoot of a project started by Gordon Blair in 1979.

http://www.google.co...tents/US4253433

Also look at this. two carb set up with direct ports to the cylinder.

http://www.google.co...tents/US6644251

Think of a 3 carb set up with a carb for each port in the cylinder that only open up at full throttle. and one carb in the traditional manner to start and run at low speed

The top end would only be limited by the mechanical limits of the rotating assembly.

hey pal, i might have a spare TUNNEL RAM or TRI-PAC laying around in my garage you could try out!

 

[Michael Caruso]

go a head yuck it up!!!!!!!!!!!

Have not broke any thing since I got theses new pistons.

got to try it just looks too cool not to.

Two barrel carb on a CMB 1.01 why not?

Got it all in my head just waiting to explode. :wacko:

Just think about it when the secondary kicks in and it spools over the top

Just like any IC engines as with our little ones you can get the carb area too large easy. Based on engine displacement, port area and rotor timing just the intake side. Good luck I hope you find a better combination than you have now.

I have bin making larger carbs for my 1.01 and have not found to large of a carb yet. the problem is the window on this eng is to small for the size of the eng to produce its maximum power.

Opening up the ports takes this eng to a higher level but the intake is the choke in the system.

The oval boar carb I run now fills the window and is only equal to a .580 round carb.

The program I use calculates at least a .650 to a .750 carb is needed to operate at 28000.

Now if the eng will hold up to higher RPM a much larger carb will be needed.

A second intake track is the only way to feed this much air.

Do not know if you don't try.

A horse of a different color now I understand why you are adding the 2nd carb in another location. I like your reed idea it has the possibility of not only more total power but keeping a wide power band too! Sounds good I agree you have to try it.

 

[dwilfong]

go a head yuck it up!!!!!!!!!!!

Have not broke any thing since I got theses new pistons.

got to try it just looks too cool not to.

Two barrel carb on a CMB 1.01 why not?

Got it all in my head just waiting to explode. :wacko:

Just think about it when the secondary kicks in and it spools over the top

Here is a carb.

http://www.google.co...tents/US7104253

Only kidding man , you never know till you try !! :lol:

I know Tom.

You and Andy are a pain in my you know what.

All ways pulling my head out of the clouds.

 

[dwilfong]

http://www.google.co...tents/US6216650

Here is a link to what sparked my interest.

This was summited by Zenoha.

This was a off shoot of a project started by Gordon Blair in 1979.

http://www.google.co...tents/US4253433

Also look at this. two carb set up with direct ports to the cylinder.

http://www.google.co...tents/US6644251

Think of a 3 carb set up with a carb for each port in the cylinder that only open up at full throttle. and one carb in the traditional manner to start and run at low speed

The top end would only be limited by the mechanical limits of the rotating assembly.

hey pal, i might have a spare TUNNEL RAM or TRI-PAC laying around in my garage you could try out!

A two barrel will suffice for NOW!!!!!!!!!!!!

 

[El Zorro]

Back in 1969 when I was a Senior in high school, I had been flying R/C airplanes for about 2 years but I was mostly still flying controline Combat and Rat Race airplanes. I was doing my own engine work and one of the men I flew R/C with was getting into Pylon Racing. K&B had some powerful Series 67 .40 size engines out at the time which were the engine of choice in our area. These were rear disk rotor racing engines that you normally used a pressure fuel system with. K&B also had a potent front rotor engine that most parts would interchange with the rear rotor engine. I got an idea! What if you took the rear rotor engine and bolted on the front rotor crank and housing and ran BOTH the front rotor venturi and the rear rotor venturi? All I had to do was machine a hard steel pin to press into the hollow crank pin on the front rotor crankshaft to drive the rear rotor and presto! A.40 size racing engine with two intakes. Using the usual pressure fuel system for these aircraft at the time, we would use a "normal" setting on the front venturi and do all of the fine tuning on the rear venturi needle valve. No tuned pipes on these engines yet, but we did use what was called a "mini pipe", which was about 1 inch in diameter and 4 inches long ( and VERY loud ). When we did get to fly the airplane it was VERY fast. I don't think he flew it more than a few times before he strained it though a line of trees with the fuselage coming out on the other side like a spear. The pilot ( not me ) was more use to 100 MPH Pattern airplanes and not 160 MPH Pylon Racers. I also tried this same engine on a controline Rat Racer and it did not do as well as I had hoped. It did better on the R/C plane I think because it would "unload" the propeller more to put out more power. Anyway, just wanted to share this story for those of you who are thinking about the two carb thing.

Dick Tyndall