Pipe & pipe length reccomendations

[John Knight]

Thanks David,

I have one of those pipes but I had already opened up the stinger as per Andy's suggestion. I'll set it up @ 9 1/2 to begin with. What exhaust timing is that 28K achieved with on that pipe, if you don't mind sharing?

Tim

127 trans 130 boost 190ex; clearance at .009 at.41cc 9.2CR 1deg angle. strait sides and bottom on chamber.

This is in a mono running a AB 5077B/3 60 to 64 MPH. will also run a X457 with similar results.

This is a highly modded 45RS.

But from testing different pipes and eng setups have found pipes do have a sweet spot that mods and setups will work around. seams the pipe is the major controller of the power the rest is just to fine tune. This has just bin my limited experience with it so far.

David

190 exhaust timing - holy cripes!

 

[Jack ODonnell]

Thanks David,

I have one of those pipes but I had already opened up the stinger as per Andy's suggestion. I'll set it up @ 9 1/2 to begin with. What exhaust timing is that 28K achieved with on that pipe, if you don't mind sharing?

Tim

127 trans 130 boost 190ex; clearance at .009 at.41cc 9.2CR 1deg angle. strait sides and bottom on chamber.

This is in a mono running a AB 5077B/3 60 to 64 MPH. will also run a X457 with similar results.

This is a highly modded 45RS.

But from testing different pipes and eng setups have found pipes do have a sweet spot that mods and setups will work around. seams the pipe is the major controller of the power the rest is just to fine tune. This has just bin my limited experience with it so far.

David

David, How are you measuring the 190 ex you are talking about. Is it just in the center or all the way across ? J.ODonnell

 

[dwilfong]

Thanks David,

I have one of those pipes but I had already opened up the stinger as per Andy's suggestion. I'll set it up @ 9 1/2 to begin with. What exhaust timing is that 28K achieved with on that pipe, if you don't mind sharing?

Tim

127 trans 130 boost 190ex; clearance at .009 at.41cc 9.2CR 1deg angle. strait sides and bottom on chamber.

This is in a mono running a AB 5077B/3 60 to 64 MPH. will also run a X457 with similar results.

This is a highly modded 45RS.

But from testing different pipes and eng setups have found pipes do have a sweet spot that mods and setups will work around. seams the pipe is the major controller of the power the rest is just to fine tune. This has just bin my limited experience with it so far.

David

David, How are you measuring the 190 ex you are talking about. Is it just in the center or all the way across ? J.ODonnell

Jack I cut just a very small arc in my ex port it is almost flat. I like that quick unload of the high pressure. I also make the ears as I call them wider and at a different angle. I think this also helps in the pipe loading of the cyl. Just my thinking. But it seams to work. I also round the top of the port and check timing with a bright lite shining in the ex port. this I feel gives a more accurate timing number. the window closes very fast. I pay close attention to the closing rate. It is just some thing I see in my minds eye. :blink:

I was thinking that if some one could make a piston speed calcuator to map piston speed at all points in the cylinder it would open up a whole differn perspective of the shape of ports. then you could see rod lengthh to stroke maping in relationship to the speed of the piston in its travels thew the Clyinder. would change the timed port calculation to a realistic view.

Ok Im done sorry got carried away again. these dam toy boat eng. :lol:

David

 

[dwilfong]

David i have a Piston Speed calc in the Software i use

191 Degree's on my Picco

Greg

Dose it map piston speed at diffrent points in the cyl or just and overall speed?

 

[Nigtmare]

Tim try the AB parabolic pipe at 9" and a 1462 prop h34r:

(you will never use a 1657 again)

Nick