Getting rid of the exhaust, down-pipe open?

[someguy1984]

Currently, i have a Thermal research and development cat-back. (stock cat)

If i cut the cat-back off, (including the catalytic converter) and get a 3inch down-pipe and leave it open, how much of a gain would i see over what i have now?

Also, how much of a difference would it be if i got the down-pipe and kept the cat-back? I would think open would be greater power...

The only reason why i don't like my exhaust tip, is because of the build up that gets on the bumper...It makes me want to cut it off, . Not only should it be faster, but the car will stay cleaner and be essentially lighter...(probably about 100lbs with catback and muffler off)

 

[quattro527]

Currently, i have a Thermal research and development cat-back. (stock cat)

If i cut the cat-back off, (including the catalytic converter) and get a 3inch down-pipe and leave it open, how much of a gain would i see over what i have now?

Also, how much of a difference would it be if i got the down-pipe and kept the cat-back? I would think open would be greater power...

The only reason why i don't like my exhaust tip, is because of the build up that gets on the bumper...It makes me want to cut it off, . Not only should it be faster, but the car will stay cleaner and be essentially lighter...(probably about 100lbs with catback and muffler off)

What turbo are you running? Anything shy of a TD06 turbine, you really won't notice the difference between a 2.5" vs. a 3.0" other than the noise. You MAY notice a little better ramp up down low on the 2.5", while 3.0" will yield a better top end...but the restriction is not the downpipe, but rather at the turbine.

Personally for me...that 1-2hp extra gain is NOT worth the 20-30dB of extra noise..but that's just me though.

And unless your thermal exhaust is made of cast iron, I really do not think it weights 100lbs. If you don't like the tips, you can always replace it.

 

[kahl23]

Didn't you just say you wanted to do simple mods? Hacking off the exhaust is a really stupid idea for any car that isn't an all out racecar, in my opinion. As a general rule of thumb the best exhaust on a turbo car is no exhaust, but if you're still running the T-25 then I doubt you would see much improvement by running an open dp rather than running a full 3 inch turbo back, the turbo is simply too small; the size of your exhaust isn't limiting your power output, your tiny turbo is. Also you have to realize that running an open downpipe terminates the exhaust right under the driver's seat, making it loud as hell when you're driving around. If it were me, I would get the downpipe and run the thermal. If you really really want the open downpipe, look into electronic cutouts. Also, some vendor on here makes a rear bumper guard for 2g's out of CF, get that if you want your bumper to be nice and soot free.

 

[1992awdlaser]

The only reason YOU will see an improvement is because of the removal of he cat. Also, you entire exhaust doesn't even weigh close to 100lbs let alone you ca back.

 

[JMiller]

I've ran open downpipe on my T25 before. The loudness of the exhaust gets annoying after about a week, and your neighbors car alarms will get a good work out. As far as adding power, spool up was almost instant on the T25 with 3" FMIC and 2.5 piping at 20psi and 3" downpipe(with the 3" catback bolted up spool up is a little below average because of the intercooler setup i have). But the driveability of the car changes(or might be just mine) when going from boost to vac. it will pop and backfire a little the whole car will vibrate a lot and you get a lot of unwanted attention(cops, Honda's, etc.) So my .02 is leave your catback but unbolt the downpipe from the cat just to see how you like it if you don't then put it back, if you do then leave it.

 

[quattro527]

I've ran open downpipe on my T25 before. The loudness of the exhaust gets annoying after about a week, and your neighbors car alarms will get a good work out. As far as adding power, spool up was almost instant on the T25 with 3" FMIC and 2.5 piping at 20psi and 3" downpipe(with the 3" catback bolted up spool up is a little below average because of the intercooler setup i have). But the driveability of the car changes(or might be just mine) when going from boost to vac. it will pop and backfire a little the whole car will vibrate a lot and you get a lot of unwanted attention(cops, Honda's, etc.) So my .02 is leave your catback but unbolt the downpipe from the cat just to see how you like it if you don't then put it back, if you do then leave it.

I second that. The first few days of driving on an open dump WG, the car felt FUN. After a week or two, it got real annoying real fast.

 

[someguy1984]

Alright, thanks guys. You've convinced me that cutting the exhaust is stupid and not beneficial enough for how annoying it is. My car actually has a pretty deep sound now.

Honestly, i don't feel like wasting the money on a downpipe...Their is no point, since i'll be leaving and the car isn't going to be fast anyway...I kind of want it a little louder though. If i remove the cat and put a 3inch pipe in it's place, how will it sound through the catback? Will it be too annoying, will i see any HP gains?

 

[chico904]

If i remove the cat and put a 3inch pipe in it's place, how will it sound through the catback? Will it be too annoying, will i see any HP gains?

It will definitely be louder. And yes there will be a gain in performance.

 

[someguy1984]

Can you give me a ball park by how much?

Also, i assume my engine light will come on...Is this a problem? Could it lead to something bad happening in the engine, or anything?

 

[1gDSM4g63]

It depends on what turbo you're running. It your running a little midget 14b turbo i highly doubt you'll notice a difference but on the hand if you run a high flowing monster turbo there would be a lot of gain.

 

[crimsondragon]

Instead of asking questions on what mods to do, maybe you should ask why it's dirtying the bumper the way it is. It sounds like you're running rich.