What if I cut swirl grooves in my intake manifold to create a venturi effect? I have seen products sold for cars and recently dirtbikes that go on the carb and have grooves that are cut counterclockwise and swirl the air to increase power and response. I don't know if this works and would like to know if this would help. I was thinking about doing it to the carb but I have the stock carb and ofcourse it has a butterfly setup in it and it wouldn't work right so I figured doing the manifold. Any ideas if it would work? Does it really work or would I be wasting my time?

 

I think that will be good but I think that the power is made because when the air is forced around the throat of the carb it has a farther distance to travel. This causes a greater ram effect from more velocity and more power will be made during the cam overlap. We all know about the cam overlap is where all the power is made. I think this is also one reason alot of people in the racing industry swear by velocity stacks. IMHO you may get more from modding the rubber tube the stock carb come with.

 

Not to sound dumb but what do you mean by modifying the rubber tube? Do you mean the vacume slide tube? Or do you mean the rubber boot between the carb and manifold?[img]i/expressions/face-icon-small-blush.gif[/img]

 

I mean the tube from the filter. When I say mod I mean either make it fit the 45mm or find a way to keep it from collasping at WOT

 

Pushinthelimit- your are heading in the right direction, at least thinking of ways to increase the intake velocity.
High velocity port your intake track - that will give you better cylinder filling which in turn = more power! if your not sure how to accomplish that ask and I'll tell you.

hurycne said:
" This causes a greater ram effect from more velocity and more power will be made during the cam overlap. We all know about the cam overlap is where all the power is made."

hurycne you will need to clarify your statement!

"All the power " is made by properly filling a well sealed cylinder with the correct air fuel ratio, compressing it and igniting it at the correct time with good spark!- this is the only time POWER is made.

About 15 degrees before the top of the piston stroke,(TDC) the intake valves open. This is also called the camshaft overlap period because the intake and exhaust valves are both open a small amount at the same time. (the exhaust valves are closing and the intake valves are opening.)

The low pressure from the exiting exhaust creates a flow pattern across the top of the cylinder that draws fresh intake mixture into the cylinder to displace the last remaining spent gases. This is only the beginning of the intake stroke not where "all the power is being made" Cam overlap is necessary for the scavenging effect it has in ridding the cylinder of spent gases so the fresh charge can more completely fill the cylinder- but there is a lot more to making power than "cam overlap" wouldn't you agree?

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No Longer Stock

 

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Yes what you said. When I say the power made I mean without changing cams or compression. Once the intake valve is closed the motor does its work for how it is setup. Yes you want to get the max cylinder fill. The more air and fuel the more power. intake velocity makes this possible and cam overlap is a vital key especially and high rpm. If you can make the air that goes into you motor flow like water then you have it mastered

 

I say we take a holley 4bl carburetor, a roll of duct tape, and a 12" piece of pipe and fabricate a custom fuel system, at the same time drill some holes in the cylinder and add some spark plugs, add some MSD Coils, MSD 7AL ignition.....oh $hit were all lost again....forget about it

 

I am just saying that the tube and the formentioned cut grooves for the air all do the same thing. When the valves open it gives the motor the best change to make it all happen and make the most HP.

 

Great ideas guys, thanks! I have made my tube so it wont collapse at WOT, but like I said I have the stock carb. So. should I do this to my intake manifold or the carb? I am thinking it would work better on my intake manifold. Should I port my intake or just make my swirl grooves? Do I need to do anything to my carb boot between the carb and manifold? Keep the ideas rollin!