Dumped Exhaust

im pretty much gonne get this http://www.dmhperformance.com/contactus.htm installed before my cat.
anyone have any imput about this?

ViciousBread wrote:

im pretty much gonne get this http://www.dmhperformance.com/contactus.htm installed before my cat. anyone have any imput about this?

If you're going to go that route,you need to do it after the cat,because if you have it installed before the cat,you'll throw a check engine code.The rear O2 sensors usually need to be turned off,via custom tuned PCM.

haha, im pretty much gonna install it as close to the dp as possible.
i want yo get as much sound and performance out of it as possible. haha
But thanks for the heads up!

^^ Your welcome.

Can't you get equally better power out of something else for the money? If the power gains were so awesome with electronic cut outs, they'd be used way more often. I've rarely seen a street tuner car with cut-outs.

Aken wrote:

Can't you get equally better power out of something else for the money? If the power gains were so awesome with electronic cut outs, they'd be used way more often. I've rarely seen a street tuner car with cut-outs.

That is because very very few cars are actually able to outflow their exhaust.

$200 seems awful expensive just to dump your exhaust. Have a shop cut the cats out weld in a new muffler (or just remove the muffler). You'll save yourself some money.

word

PwrRngr wrote:

$200 seems awful expensive just to dump your exhaust. Have a shop cut the cats out weld in a new muffler (or just remove the muffler). You'll save yourself some money.

its the fact that you can change the from my regular stock exhaust, but i can have that roar, and power whenever i want.

I'd like to see if electronic cutouts actually provided a worth-while power boost on your four cylinder.

Edit: And actually sounded good...

it will acctually work better with my 4 cylinder turbo.
from what i've read (not an expert) that when its open it creates less back pressure which does wonders with a turbo.
so im hoping for 15+ hp/tq

ViciousBread wrote:

it will acctually work better with my 4 cylinder turbo. from what i've read (not an expert) that when its open it creates less back pressure which does wonders with a turbo. so im hoping for 15+ hp/tq

If it's behind the cats it's not going to relieve much backpressure (some backpressure actually helps torque) unless your muffler absolutely sucks. If you put it before your cats then you’re going to screw up your O2 readings and make less power.

PwrRngr wrote:

ViciousBread wrote: it will acctually work better with my 4 cylinder turbo. from what i've read (not an expert) that when its open it creates less back pressure which does wonders with a turbo. so im hoping for 15+ hp/tq If it's behind the cats it's not going to relieve much backpressure (some backpressure actually helps torque) unless your muffler absolutely sucks. If you put it before your cats then youre going to screw up your O2 readings and make less power.

i dont think you realize that im only going to have it open for 30 seconds at a time max.

ViciousBread wrote:

PwrRngr wrote: If it's behind the cats it's not going to relieve much backpressure (some backpressure actually helps torque) unless your muffler absolutely sucks. If you put it before your cats then you're going to screw up your O2 readings and make less power. i dont think you realize that im only going to have it open for 30 seconds at a time max.

The point still stands. If it's before the cats you're going to screw the O2 sensor readings and it'll result in less power (the O2 readings are one of the most important sensor readings on the car). If it's after the cats then you're not going to gain much unless your mufflers are REAL restrictive. It doesn't matter if it's open for 30 seconds or all the time.

It's your money so you can do what you want. I'm just letting you know that it's not going to be much of a change (except for sound).

ViciousBread wrote:

PwrRngr wrote: ViciousBread wrote: it will acctually work better with my 4 cylinder turbo. from what i've read (not an expert) that when its open it creates less back pressure which does wonders with a turbo. so im hoping for 15+ hp/tq If it's behind the cats it's not going to relieve much backpressure (some backpressure actually helps torque) unless your muffler absolutely sucks. If you put it before your cats then youre going to screw up your O2 readings and make less power. i dont think you realize that im only going to have it open for 30 seconds at a time max.

O2 sensors adjust fuel trims multiple times per second.

There used to be a hillbilly truck around town here with one of those.. he'd be driving then all of a sudden he'd dump it and rev it and it'd scare the hell out of anyone who didn't expect it.. I dunno how he did it though, def not something that expensive.. it woulda been worth mroe than the truck

Worked quite well on me lol

PwrRngr wrote:

ViciousBread wrote: PwrRngr wrote: If it's behind the cats it's not going to relieve much backpressure (some backpressure actually helps torque) unless your muffler absolutely sucks. If you put it before your cats then you're going to screw up your O2 readings and make less power. i dont think you realize that im only going to have it open for 30 seconds at a time max. The point still stands. If it's before the cats you're going to screw the O2 sensor readings and it'll result in less power (the O2 readings are one of the most important sensor readings on the car). If it's after the cats then you're not going to gain much unless your mufflers are REAL restrictive. It doesn't matter if it's open for 30 seconds or all the time. It's your money so you can do what you want. I'm just letting you know that it's not going to be much of a change (except for sound).

what about if i got a catless down pipe?
your saying that wouldn't give me any power either?

clutch1 wrote:

There used to be a hillbilly truck around town here with one of those.. he'd be driving then all of a sudden he'd dump it and rev it and it'd scare the hell out of anyone who didn't expect it.. I dunno how he did it though, def not something that expensive.. it woulda been worth mroe than the truck Worked quite well on me lol

He probably had the old school cable operated cut outs.

Like these.


Or he could of made his own using a couple of throttle bodies and lawn mower style choke cables.

just got back from the dealership.
only thing that it will void if the exhaust warranty.
who needs that **** anyways?

ViciousBread wrote:

what about if i got a catless down pipe? your saying that wouldn't give me any power either?

If you didn't get mil eliminators or disable the O2 sensors then you wouldn't. You would get a O2 CEL and lose power b/c of it.

what if i put it after the cat?
will it improve my performance?

ViciousBread wrote:

what if i put it after the cat? will it improve my performance?

You might get a small improvement. But that depends on how restrictive your stock mufflers are. I don't know anything about GTI mufflers but I can't imagine they are terribly restrictive.

If you're going to get it then you should also get a handheld tuner (this can turn off the rear O2 sensors) or some mil eliminators (these are what they are called for Mustangs. Might be something different for GTIs). For the Mustang, mil eliminators are $20-$30 a piece (need one for each rear O2 sensor) and they do the same thing as turning them off.

Then place the dump before the cat(s) and turn the rear O2 sensors off with the tuner or eliminators.

im gonna wait untill i have a tune and a catless downpipe.
then it will really do some work for me

why don't you just get an exhaust system? skip the cutout?

brymck wrote:

why don't you just get an exhaust system? skip the cutout?

because i dont want to spend 1.3k for a turbo back exhaust, and a cut out gives me more power then an exhaust, with a down pipe and tune.
Ive seen someones dyno results with someone who tested open and close, he got 20hp with it open.

go to an exhaust shop and have them bend you up a custom job. i'd be willing to bet it'd be far cheaper than 1300 bucks.

or i just get a cut out and get better stats than a full exhaust.

how are you going to be using this car?

i'm pretty sure that cutouts in most places are illegal. So the only time you would be able to legally use this would be on a track somewhere. Whereas an exhaust system, you'd be able to reap the benefits of it whether you are on the street or on the track.

Exhaust = have benefits all the time and very little risk of harassment by police for it
Cutout = use off the road only or risk being hassled by police.

you ever think about if i have the cut out open ill probably be exceding the speed limit?

brymck wrote:

how are you going to be using this car? i'm pretty sure that cutouts in most places are illegal. So the only time you would be able to legally use this would be on a track somewhere. Whereas an exhaust system, you'd be able to reap the benefits of it whether you are on the street or on the track. Exhaust = have benefits all the time and very little risk of harassment by police for it Cutout = use off the road only or risk being hassled by police.

Usually people who run cut outs on their street vehicles,could care less about it being legal.

I wouldn't do that unless you plan on boosting it. My friend kim has a turbo VR6 Jetta that has a dump valve that opens when in hard boost, apprx 10lbs and up. Makes a hell of a difference though.

bhowell879 wrote:

I wouldn't do that unless you plan on boosting it. My friend kim has a turbo VR6 Jetta that has a dump valve that opens when in hard boost, apprx 10lbs and up. Makes a hell of a difference though.

I believe new GTIs are boosted.

PwrRngr wrote:

bhowell879 wrote: I wouldn't do that unless you plan on boosting it. My friend kim has a turbo VR6 Jetta that has a dump valve that opens when in hard boost, apprx 10lbs and up. Makes a hell of a difference though. I believe new GTIs are boosted.

Ahh, I wasn't sure. If thats the case then do it.

bhowell879 wrote:

PwrRngr wrote: bhowell879 wrote: I wouldn't do that unless you plan on boosting it. My friend kim has a turbo VR6 Jetta that has a dump valve that opens when in hard boost, apprx 10lbs and up. Makes a hell of a difference though. I believe new GTIs are boosted. Ahh, I wasn't sure. If thats the case then do it.

yeah, i plan on getting a dump once i get a downpipe, and a tune.