HouseofKolorEX

Hey, noob girl here. I've been looking at all kinds of catbacks online and at the local shop... but all the tail pipes on them are grapefruit shooters... like 4". I want a catback but I only want a 3" tailpipe. I've been able to find a few axleback's that are 3". Am I going to notice a huge diff. between the axleback 3" and a catback 4"? A lot of HP? What about the sound? Let me know what I should do. :driving:

Tirod

the diff between an axle back and catback is that the axle back from the axle on out.. the catback replaces the piping from the cat on out.. 2.25" is perfect size for piping (mandrel bent) and no more then a 3" tip... does this answer yer q?

DelSolSIinMD

It depends on the car, and the size of the piping, etc.

For instance, a short-wheelbase car will notice less drop in HP between cat-back and axle-back because the exhaust piping between the cat and axle is shorter. Long-wheelbase cars will therefore see larger gains from cat-back.

In any case, cat-back is always going to result in more HP unless the piping is too small or too big. Tirod is right, 2.25" is perfect for a naturally aspirated car. Also, like he said, make sure the piping is mandrel bent.

I don't have any charts handy, but I bet you'd get about 50-75% of the gains of a catback from an axle-back. In other words, if you made 10 hp from a catback, you'd make 5-7.5 hp from an axle-back. That might be optomistic, though. I wonder if anyone has any good research on this....

SRT_Andy

I think my Greddy EVO is 2.25" and it works just fine. The noise level is very low, too......

str8edgexx

On a Honda, you're not going to get much (any) gain from a Catback...maybe 2 hp or so if you're lucky....if you just want the look and sound, and want to save your money, get the axel back. If you want to spend lots of extra money for that 2 hp gain, get the catback

flipped cracka

i would think if you had a header, you would want a catback, correct?

STOCK96civicDX

Exhaust is such a tricky thing because when you make it easier for the exhaust to get out, you have to compensate where the air and fuel come in. When you add a high flow exhaust and don't compensate in the intake area, your engine will run lean, as there will be not be enough backpressure to keep the fresh air/fuel mix in the engine, it will simply start to slip out when the exhaust valves are still open. I've been through this scenario with my motorcycle. I had to replace the carb jets to add quite a bit more fuel to the air/fuel mix in order for it to run correctly. The key to aftermarket/performance exhausts is evaluating WHY you want it. my motorcycle has an aftermarket exhaust because it made my midrange and high rpm torque and hp curves smoother. with a longer exhaust system on a car, it might not make too much of a difference if you're talking about a cat back or just a muffler, but it will still change everything slightly. remember, your car was set up by the manufacturer to run a certain way with the equipment on it. when you change a component such as exhaust, make sure the air/fuel delivery is adjusted accordingly to compensate or you are just wasting your time and possibly causing damage to your engine.

niko

does anyone know how wide (inches) the exhaust piping is on a 93 civic VX hatch? If I get a B18b should I just replace the muffler? (I dont like spending money on pointless/ low significance mods) Please help

Motohip

Are you kidding? You think the Integra makes it's power with a universal honda muffler? No, it has a muffler designed for that car. The VX was made to use as little gas an possible, not for horsepower. If you keep that stock muffler, you're not getting all the power benefits of the B18B.

tokyoracer

good post... so how would i go about in increasing air and fuel? i already have a cai... but it only sucks up more air when i floor the gas pedal. as for fuel... i guess i can use a FPR to do that... but then how much psi should i turn it to ensure proper amount of fuel & air mixture? or i guess i can go apexi vtec controller to richen or lean out the fuel... damn! now i am confused...