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Old 12-24-2008, 04:37 PM   #1 (permalink)
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Drag-pipe blues

If you love straight pipes, are on the cheap, or both, here's a way to do the deal and still maintain a little backpressure and exhaust velocity. It takes a welder and parts are cheap, but the best part is: It's adjustable......

It's not totally my idea and it's my understanding, it goes back to the 70's if not older. I'm just doing a little penwork here and sharing it with you that may not know about it.

You need:

1.) 3/4"-7/8" washer
2.) 1/4-20 bolt-1" long
3.) 1/4" washer
4.) 1/4-20 nut

Weld the washer to the bolt. Drill a 1/4" hole 6-8" back from the tip of the pipe. Insert washer into the pipe, and slip the bolt into the hole in the pipe. A telescopic magnet works nicely....

After the washer/bolt is in the hole, apply the washer and nut. Double nutting is OK too.

After you have the washer in, you adjust its angle, to achieve the sound and backpressure you want. This is a case where your Ass-Dyno is a good tool, and you'll be able to feel where the dead-spots are and know that a little more washer (restriction) is needed.

This isn't too far off from some major, baffle MFGer's designs and a whole lot cheaper too.

FYI: Also keeps Jonny Law's baton/nightstick from entering a pipe that would normally be non-baffled. May not pass a decibel meter, but will prevent a "Defective Exhaust" citation in most states.


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Old 12-24-2008, 04:38 PM   #2 (permalink)
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Despite how simplistic this looks, when installed, I noticed a difference from straight bladed to full baffle, in the low/mid range areas. Dyno runs have noted in some cases, by adding a 1/4" bolt to the exhaust, created enough of an exhaust velocity change to gain another 1-2 horsepower on some free flow exhaust.

The sound is a full, deep, rich (Read:LOUD) drag pipe sound, without running lean or losing tremendous amounts of torque where needed.

2- 3/4" washers welded to 2- 1/4-20 bolts:



Drilled hole 7" back from inner most tip of opening. Drill slightly then larger then 1/4" to be able to slide the bolt in partially on an angle:



Slot the bottom of the bolt, so when installed, you know what angle your "baffle" is facing:



Drag pipe camera:

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