I don't know if anyone had seen this yet(I did a search of the forums and couldn't find anything), but Racing Beat has posted results of a dyno test of a 2002 "stock" Protege ES, both with and without their cat-back exhaust. They claim a maximum increase of 4.7 hp at 5750 rpm. That's not a whole lot of gain for the price, but I guess you have to factor in sound and looks as well and then it's probably worth it. One of these days when the $$ starts coming in...

"The following dyno test was conducted on a low mileage, "stock" 2002 Mazda Protege Sedan ES. Prior to the dyno test, the oil level was checked, the air filter was cleaned, and a new set of factory spec NGK spark plugs were installed. The dyno tests were conducted on 5/13/02 at Dynamic Autosports in Irvine, CA." -quoted from their site discussing the dyno runs

http://www.racingbeat.com/FRprotege.htm
Go to the bottom of this webpage and click where it says "Click here"--it will take you to the page along with plots from one run. Pretty heavy losses in torque is what it looks like from the plot (the darker color), but according to the numbers, the exhaust gives a 5 ft-lb increase in torque as well so maybe they just inadvertently switched colors on the plot.

Just thought I would give everyone a heads up unless this is all old news, and if it is - Sorry!

 

Sorry about the link...I just tried it and it doesn't quite work. If you're familiar with the site, you probably know where to go. If not, just go to the pull-down menu on the left and choose the "Exhaust" from the menu. Then click right below that on one of the "Protege Exhaust System" links. Now go to the bottom of the page that comes up and you will be there.

Finally!

 

well the racing beat exhaust dyno results have been mentioned here a while back, but no one took notice of the switched colors on the torque lines, very weird....

but yeah, 4hp for about $500, not a whole lot gains, but at least they gave out a REAL dyno number, not some 'estimated' gain

honesty is always good, well most of the time

 

Now if I can get them to sell me the center pipes without the muffler. then I'll be happy

 

Keep in mind this is bone stock. The stock Exhaust on the Protege is not much of a bottleneck when the rest of the car is stock. Add a CAI (and other mods) with that exhaust and you'll see a better gain.

 

Good point, funkrider, about the gains increasing when accompanied by other aftermarket parts. I guess exhaling through a fire hose doesn't give me many advantages in air quantity/velocity if I'm inhaling through a straw!

 

There is still an exhaust restriction even with the cat back exhaust. The cast pipe right below the primary cat is the biggest restriction in the stock exhaust.