I've been lookin around at some exhaust upgrades and I'm not reallyt sure what a cat-back exhaust is. Please explain, anyone who knows.

 

It consists of a b-pipe and a muffler. Basically its all the piping from the cat to the muffler. Not sure of how many hps you could get ~7-10?

 

You can upgrade your exhaust starting with a Y-pipe. This item (Available from Stillen , Cattman, & others) replaces the stock piece, which has pre-cats in it. (The pre-cats help reduce emissions while your main cat is still heating up to normal operating temps.) The Y-pipe attaches to the exhaust pieces on each side of the engine, and runs back to the catalytic converter. Technically, this is for off-road use only, because it doesn't have the pre-cats in it. But once your main cat is up to normal operating temperature, you should pass emissions testing with flying colors. These are stainless steel, mandrel bent, precision welded pieces that should bolt right on, no sweat. Be prepared for a bees in a can sound, which is normal. You can reduce that with header wrap... A y-pipe is good for 15-25 HP, depending on the car and who you ask. Nice gain, huh?

You can upgrade your catalytic converter. The aftermarket pieces feature less restriction than stock cats. R/T makes one that sells for around $200, I think. They are louder than stock, but not too bad. You might pick up another 7-10 HP with one.

The B-pipe runs from the Cat back to the muffler. Stillen and others make these. They have tuned resonance chambers, they are mandrel bent, and some are over-sized to increase air flow. Cost varies, but not too bad. You might pick up another 5 HP with this.

The muffler. There are a ton of low restriction mufflers on the market. I advise you use a stainless steel version, so it will never rust. GReddy makes a nice one. These guys run anywhere from, say, $250 to $650. The sound runs anywhere from a buzzing can to a nice, deep, meaty roar, depending on brand. (Did I say GReddy makes a nice one?)You might get 5-7 HP with this.

Lastly, it makes sense to put a high-flow air intake on your engine, too. Used in combo with your upgraded exhaust, you will derive maximum benefit with a freer-breathing engine.

The results: You might lose a tiny bit of power in the low RPM range, because your engine needs some back-pressure for low end grunt. Most folks do not notice a significant loss, OK? You WILL pick up HUGE gains on the top end. (Wahoo!)

Good luck.

 

let me get this straight! correct me if i am wrong. u r saying if we do these mod (according to ur numbers):
15...........25..........y-pipe
7............10..........cat-converter
5............5...........b-pipe
5............7...........muffler
??...........??..........intake
equals
32...........47..........hp gain not including intake???

 

Yes. That's according to published data from the various manufacturers of the components listed in my response. How much do you think we should dismiss as simple puffery? I'm not sure either. Many of the manufacturers' claims ARE supported by dyno testing. I suppose there would also be variation from car to car. Let's say the claimed increases are off by a whopping 50%. That would still allow a result of about 20-25 HP, with the intake installed. I have an intake, muffler, and b-pipe on my '95 Max SE, and my butt dyno indicates a significant gain in acceleration -- especially at the top end of each gear. (Most everything I read indicates that the most significant gains come from a y-pipe. I don't have one yet, but I sure would like to try one.) My best 1/4 mile to date was a 14.89 sec run at about 94 MPH. Before I added my mods, my 1/4 mile times were in the low 16s at about 88 MPH. My top speed now is 140MPH+. Before my mods I could barely surpass 130MPH. I'm convinced that the mods I made provided gains in the neighborhood of 20-30 HP. There is not a stock Maxima that can keep pace with me now, much to their chagrine! I believe my results are fairly universal among those who have modified their Maximas. I think it's worth your while to try some of this yourself. You'll see... Thanks for the response.

 

Listed hp gains can be very misleading. Most companies and even users seem to be most concerned with max power, which usu peaks at high rpms like 55oo or more. There are lots of mods which give you lots of extra horses at lower rpms, but don't add much to the max. For instance, Lets say, hypothetically that the max makes 190 and with a y pipe makes 200 at max power at 6000. What happens in the mid though? Mabye at 3000 rpm the car usu makes 140, but is now making 165? This would not be a max hp increase, so most mfg's won't list it, but what a difference in drivability. Anyway, just food for thought. Those numbers sounded large to me too. From what i gather, the y pipe is the best thing you can get. ALOT of people don't like their muffelers noise, and this part makes the LEAST power (looks good though) and just so you know, at Full throttle, most intakes are louder than the mod exhaust. I love mine. Go with intake first, y second, cat third, b next and muff only if you really want it. Oh, and if you get the y, make absolutely sure you get the right gaskets, heard tons of people get screwed on this.