Air Flow / CFM's

[H2OPERF]

My dad had a regular 3 cyl mcCulloch, he said they had a rotary valve race version. Dave

[olboatman]

Ironic end of the story ... by the time the tuned exhaust was produced and confirmed as a legal stock replacement - Champion was out of business, the spare parts and manufacturing tooling were in storage in box cars on an unused railroad siding.

Thanks Mark75H for a very interesting history lesson and the pic of the "prototype" is priceless! Gary

[Mark75H]

My dad had a regular 3 cyl mcCulloch, he said they had a rotary valve race version. Dave

http://www.screamandfly.com/showthre...ure-amp-racing

[Chaz]

I would hate to see what the inside of that pipe looks like ....
Looking at the turn twords the center about mid clamp the pipe makes a big change in cross section area , goes back / forward / down all in one expanding sweep , then kinks back and down increasing to at least double the area at exit .
I know it's a prototype and they cleaned up the production model , but I can't help but wonder why they would go against the grain when it comes to drastic size and angle changes . It's still a practice they haven't let go of if you look at the 3.0L exhaust tract from port to exit ....

I do see steps taken to equalize the header ( primary ) pipe length . That's something they lost on current V-6's .
How did it come to be that OMC went with a 90* V with lots of room between the cylinder banks and a well thought out primary pipe arrangement , while Mercury seemed to go with making a tighter package forgoing having room to design a proper exhaust conduit , and a crankshaft that has natural balance issues ...?

[dwilfong]

Changes in diffuser angles is used to tune the response of the scavenging of the pipe.

[FMP]

http://www.google.com/patents/US3520270
http://www.google.com/patents/US3692006
George Miller, again two good reads.
http://www.google.com/patents/US3813880
R Reid

[Chaz]

Changes in diffuser angles is used to tune the response of the scavenging of the pipe.

Fong , As per usual , you missed the ..................... POINT



I do my best to actually improve flow , a big part of that is building uniform parts ..



Which also includes the fit and quality on the weld inside of the pipe as much if not more than the outside ...



Back to the divergent cone .... or more like the bad habit of Mercury breaking the 7* angle rule of thumb , instead just going for the hallway into an auditorium effect .
I'm sure you can see where the left side of this port is totally dead ....



What has the aftermarket done (so far ) to fix it .... ?
If one ski slope is bad ... adding another to make the tract look like the slide at a water theme park has got to be better .....



And did they really stick two pieces of 4" channel against a slab of 5/8ths plank to build a mold .... LMAO

[dwilfong]

Chaz and what was the point?????
Why did it change cross section so much?????
No I got that point and made a reference to WHY it changed cross section so much.


Not all after market tuners for a Merc 2.5 are 2x4's




Not all divergent cones fallow the rules. Some even use water injection to change the tune.

[Chaz]

Chaz and what was the point?????
Why did it change cross section so much?????
No I got that point and made a reference to WHY it changed cross section so much.

Your really my bouyyyyy "Power" signed in under a different name , ain't ya ... ?
I promise , I won't cover so much material all at once .... If nothing else , go back and look at the pictures .....

Not all after market tuners for a Merc 2.5 are 2x4's

Pppsssstttttttttt ... the 2"x4" casting is a THREE LITRE tuner ...
It's OK , I understand

Not all divergent cones fallow the rules. Some even use water injection to change the tune.

Nothing out of the ordinary there . Nor is it breaking the 7* RULE OF THUMB .
Try to "fallow" along . The first cone on both pipes appear to be 7* or less , Lets call it 5* . The second is a bit more abrupt , lets call it 8* . 5+8=13 See , still below 14*
If you would take the time to look in side after a run , chances are pretty good you will see the second cone does have less activity than the tighter cone .
Your welcome ....
Now , Fong , What if it had a third cone instead of a belly section or started on a path of converging ...?
Take your time 7x 3 = ___

[dwilfong]

You know Chaze If I showed a pic of that tuner and did not note it was a 2.5 you would have corrected me right?
The "point" is not all after market tuners are made like you shown.
The one pipe is a 3 section and the last cone is 25deg...................so the "RUEL OF THUMB" is not fallowed. point made?
But then again every one is your bitch now are thy not?.......So no mater what any one says you will still look like the king?
Hay if that's what tickles you pickle who am I to tell you different.
NO I don't need to post under a different name. Bully's don't SKEER ME !!!!!!!!!!
You have fun playing with your swollen head I'm done here.
Please don't disappoint the circus crowed lets see that animated response.
The show must go on.............

[Mark75H]

We are Devo

[dwilfong]

[Chaz]

Fong ,
Thanks for the correction and the many lessons on the obscure .
I'm gonna call the cone police and see if they will let you off the hook on breaking a rule of thumb by 4 degree's ... Ohhh your so daring !

I am in total shock to find out some inject water in the exhaust stream . Ohh wait , that's the way outboards have come from the factory for how many decades ... ?
In our case "dry stacking" is the exception.


Nothing personal Fong , You have made statements that were pretty far out there , I only tried to talk you down off the ledge ...
I understand that you didn't like that I caught your "slight of hand" and have been on a mission ever since . Just know many of "my quotes" are direct from Blair , Jennings , Kaaden , and the Specific Time-Area findings of Naitoh + Nomura . Which are based on fact's and math equations . Your rhetorical responses since are based on being mad .

I'm not looking to argue with anyone , just clear up # 1 , # 2 , below and I'll be happy to step away from your circus ...

There are two things I would like you to explain to me . I can't find ....

# 1) Pipe eng

# 2) fallow

Although a fallow is a parcel of uncultivated land , I don't see the relevance here ..?

[FMP]

Now that you guys are in business together , what's next?

[FMP]

Your really my bouyyyyy "Power" signed in under a different name , ain't ya ... ?
I promise , I won't cover so much material all at once .... If nothing else , go back and look at the pictures .....



Pppsssstttttttttt ... the 2"x4" casting is a THREE LITRE tuner ...
It's OK , I understand






Nothing out of the ordinary there . Nor is it breaking the 7* RULE OF THUMB .
Try to "fallow" along . The first cone on both pipes appear to be 7* or less , Lets call it 5* . The second is a bit more abrupt , lets call it 8* . 5+8=13 See , still below 14*
If you would take the time to look in side after a run , chances are pretty good you will see the second cone does have less activity than the tighter cone .
Your welcome ....
Now , Fong , What if it had a third cone instead of a belly section or started on a path of converging ...?
Take your time 7x 3 = ___

Just a visual of the low difference behind the pulse. At about 47/48 sec you see the low collapse and the rebound against the scavenged ex flame for split second as it leaves the pipe. Stacker pulse return.