Macs pretuned pipe OS46 abl - fitting placement

I'm not sure what you mean by "constant pressure". Even in a tuned pipe, the pressure wave varies. I don't know where MAC recommends putting the pressure tap, but the two most common spots are on the flange of the header and the high point of the pipe. The high point placement will result in more pressure, more constantly. Dr.1 Driver "There's a Hun in the sun!"

Thanks for the response.. You are suggesting the same locations as Mac and the same two I used. Any ideas why I would not be getting enough pressure to maintain constant fuel flow to the engine. When I put the stock exhaust on it works perfectly.

thanks

I would suggest putting the pressure tap at the high point on the pipe. One thing I have noticed with Mac's pipes is the relatively small bore of the included pressure tap- bet you would notice a positive difference with a pressure tap that has a bigger hole through it. I believe Higley makes one- a big bore pressure tap. When I flew slimers I always replaced the little ones with these.

Good Luck!

Bill Davenport AMA 28141

snipped-for-privacy@hotmail.com (V>> > I am unable to get constant

Try enlarging the hole in the fitting. Make suer you're not trying to run the engine too lean. Check the header for correct length. Dr.1 Driver "There's a Hun in the sun!"

Make sure that you don't have the tap too far back on the pipe! I could bei in the muffler section with no connecton to the inside of the actual pipe. It should be right at the point where the pipe reaches its maximum diameter.