The only number I have seen for lost HP was less than three with the splitters. Exhaust design will be much easier with them.

 

The tubes for your Pport should be thick walled and a light press fit, in the inner wall in order to support the edges of the housing when the stack is torqued up. Keeps the chrome from cracking. Fill in the water void between inner and outer housing with an aluminum filled mechanical epoxy. If there is no water, it can't leak. Devcon Plastic Aluminum if you can find it. http://www.freemansupply.com/DevconEpoxyPlastic.htm

 

The putty. Not the liquid.

 

Use a milling machine. Practice on a junk housing or two. Paul Yaw did up a nice Pport and had the pictures on his web page. www.yawpower.com. I'm on dial up until the 6th, so I didn't look through his stuff to see if any of that was still there. Leave at least 1/2" of chrome on each side to support the apex seal.

 I built one for a guy who ran it through two passes at an autocross and never developed oil pressure.

Said it ran real good. It was in a Mini Cooper woody wagon. The engine had set in his shop for two years before he ran it. (10 inch tires were not enough)

 

Keep runner (tube) ID about the same as the combined area of both stock runners. High velocity is what you want. Bigger is not better until you get closer to 10,000 RPM. 

 

Cover all of the chrome you don't want ruined with three layers of duct tape.

 

Look for 200+ HP

 

Lynn E. Hanover

 

Lynn,

I'm having a discussion off-list with a chap who is claiming the need for 2" runners for runways over 10,000 ft and hot days - in other words lower density situations where max power is needed over 10,000 ft. I have suggested he look at velocity rather than size, but I feel he has a mind-set.

What do you think about his concerns for power at altitude, does this add another dimension with PP sizing?

I understand power will be down at altitude, but don't see how a bigger port compensates for that.

George ( down under)