I tip my hat to ya sir, I am an ASE certified master tech, but I only got about 20 years experience, if ya wanna call it that

 

The chip makers and programmers outside the Jet Stage II (which seem to have a pretty huge secondary market) don't make provisions for a wildly different exhaust. The simple O2 and AIT sensors our jeeps are equipped with have an expected path from the ECM and unless the knowledge of what you have strapped on is somehow present, it simply isn't going to have a framework to work within.

A simple 2" dual exit exhaust is going to need 100 more hp over stock to be effective. It's still going to feed through the stock Y pipe which isn't going to take advantage of anything larger than the 2.5" primary tube. As exhaust gases travel through the exhaust, they lose heat and also velocity. The muffler acts as the largest heat sync in the system further slowing down exhaust gases and having dual exits creates negative pressure.

The whole thing can be greatly over thought and the best solution is to get a muffler relocation kit with single 2.5" in and out or go to your local muffler shop and have them make one with the 2.5" in and out can of your choosing.

To go any further with performance gains you need to start from the engine, get a set of headers, lose the Y pipe, buy some high flow cats change out the rest of your exhaust and then find someone who is savvy with the ECM so your A/F management can take advantage of it. By the time you're done you've spent $100 per every bhp gained, are half way to buying a RIPP supercharger and still have a vehicle that's going to get dusted by a Camry.

 

Jpop,

Thanks for your wisdom.....your posts are very interesting

For what it is worth -- the venturi reduces the 2.5' pipe down to about 2 1/8" for approximately a 3 " section of the pipe. I installed just before where the pipe heads up over the axle (in front of the Flowmaster Camaro style muffler - 1 input, two output).

I am getting better great MPG and I now have tons of torque in all RPM ranges.

 

You're welcome and I think you have a good solution for your particular issue. The best solution is probably to never go there but life's best lessons are learned the hard way just as it was with my 3" pipes on my Chevelle and paying too much money for a Banks exhaust. As a result I know way more about exhausts than I care to and I'm sure you feel the same about the physics lesson you learned from Giovanni Venturi and Borla.

 

couldn't you do the same thing with exaust tip inserts like the import crowd has used for 5-10 years. For around town driving they have an insert you can put inside the exhaust tip that can be "tuned" or adjusted. No cutting involved just get the right diameter.

 

That wouldn't really address the issue as where you're slowing down exhaust gas speed is in front of the solution. While it may make a modest improvement, nothing anywhere near what the appropriate exhaust diameter would.

Perhaps this exhaust tuning tip will help lend some insight into the most useful application of exhaust inserts.

http://www.youtube.com/watch?v=n79jSzKA0L8

 

Carburators use this because the drop in pressure at the venturi helps draw in the fuel as well as atomize it. None of which is happening or useful in an exhaust system.

The restriction creates a back pressure which is useful at certain RPM's to help the effeciency of the engine. That is why some exhaust systems are better suited for low rpm scenario's and some for high rpm's.

2 stroke engines are verymuch in need of proper exhaust systems which is why the term "riding on the pipe".

Your airplane/wing effect is totally different.

 

ROTFLOL, Saw that and it reminded my of some inserts I used to use on Ducati's when running straight pipes on the streets. At high speed/rpm's those suckers would blow out and VOILA! instant increase in power and sound. Problem was you would have to creep back in town lest you get a ticket. Now these tips they are running would het old real fast. Woo WOOOO! lol

 

LOL, yuppers, a cherry bomb would do it rightious.

As to old school, need a 65 stand bell housing and 4 speed close ratios box, or a set of headers for a 400 or an intake isky intake manifold plus a few other things I have sitting here.

I think there are more OF's here than many would think.

 

How about these...electric exhaust cut outs

Best of both worlds!

http://www.quicktimeperformance.com/QTEC/index.php