Invidia Legacy GT Catless & Catted Downpipes

[QLQ]

Is anyone using the Invidia Legacy GT Catless & Catted Downpipes? which version is smooth and maximized exhaust flow?

[Guest LGT-NY]

I have the Catless version. I love it. If you are looking for maxium flow, then the catless is the way to go. If want an exhuast that is not as loud, won't smell up the cabin with DP smell and will be better for the environment, the Catted version is for you. Catted version is more expensive though.

[QLQ]

I see~~ i also prefer the Cateless version... and i just feel maybe is too loud! and your Catless version DP is divorced or bellmouth? what s different between divorced and bellmouth?

[Guest LGT-NY]

Mine is divorced. From what understand, the divorced wastegate will keep the wastegate gases from mixing with exhaust gases which may cause turbulence in the DP and decrease flow. People have mixed opinions on whether or not there is a valid performance advantage from the divorced WG.

[QLQ]

Nice~~~~~ Does Check Engine Light will blink if run this DP? because i saw a Warning on the web which a dealer selling the Invidia DP..

[holyjoetart]

The catless version is pretty stinking loud. It threw a CEL as soon as I fired my car up. Now its off to the dealer to get my turbo replaced. Check your turbo play when you take off the Dp. Its easy!!!!

[nm]

Not to be the treehugger of the group, but the minimal power gains and increased cost as compared to the drastic emissions reductions acheived by a cat makes it irresponsible to run catless. The catylitic converter is basically the best thing to happen to our air since trees.

Also, it's extremely illegal at the federal level in the US and probably in Canada too.

[goneskiian]

Not to be the treehugger of the group, but the minimal power gains and increased cost as compared to the drastic emissions reductions acheived by a cat makes it irresponsible to run catless. The catylitic converter is basically the best thing to happen to our air since trees.

Also, it's extremely illegal at the federal level in the US and probably in Canada too.

[holyjoetart]

It would be illegal in most states. Wyoming on the other hand is not most states. No emissions laws here. It is better for the environment for me to run cats in my exhaust, but how many high-flow "cats" can pass a California smog test?

[nm]

It would be illegal in most states. Wyoming on the other hand is not most states. No emissions laws here. It is better for the environment for me to run cats in my exhaust, but how many high-flow "cats" can pass a California smog test?

Uhm, removing cats is illegal under federal law. that means, if Wyoming is still part of the US, it is illegal to run without a cat.

Define "pass"

High-flows will nearly always pass the sniffer test. And even one that doesn't is still polluting less than an open pipe.

[affinity1]

I have the Catless version. I love it. If you are looking for maxium flow, then the catless is the way to go. If want an exhuast that is not as loud, won't smell up the cabin with DP smell and will be better for the environment, the Catted version is for you. Catted version is more expensive though.

 

If your cabin smells like exhaust I think you may have bigger problems than just being catless.

[Guest LGT-NY]

^^ No, you're wrong.

 

Catless DPs are notoriously stinky.

[j255c]

Not to be the treehugger of the group, but the minimal power gains and increased cost as compared to the drastic emissions reductions acheived by a cat makes it irresponsible to run catless. The catylitic converter is basically the best thing to happen to our air since trees.

Also, it's extremely illegal at the federal level in the US and probably in Canada too.

 

you bought the wrong car, you may want to re-consider and purchase a prius....give me a break, tell that to everyone who has a motorcycle or a classic car. You're not doing much harm to our environment running a catless car.

[SBT]

I see~~ i also prefer the Cateless version... and i just feel maybe is too loud! and your Catless version DP is divorced or bellmouth? what s different between divorced and bellmouth?

 

Our stock DPs have a small opening for the turbo outlet with a "plate blank" which blocks the turbo's waste gate gas flow and forces it over into the turbo exhaust stream. Invidia DPs have a bellmouth with a curved separator in the bellmouth shaped in such a way as to create a divorced waste gate (DWG) down into the pipe. Invidia uses the bellmouth, with WG separator, on both the high flow catted and non-catted versions. Some DPs, like the Perrin versions, actually have a separate pipe that runs adjacent to the turbo exhaust pipe which feeds the WG gases back into the DP, further along in the pipe.

 

There are different schools of thought on whether a DWG offers any performance gains. I think the larger concensus is that you won't see significant improvement (read: power gains) from a DWG, until you go to a much larger turbo, where you're holding higher boost pressures further into the RPM range and you don't want to create turbulent air flow at the turbo exhaust port and potentially slow down the turbo.

 

Some just knock the catalytic material out of the stock cat and use that. Others use a bellmouth DP w/no DWG (COBB makes this) and both seem to work just fine at elevated power levels on stock and larger turbos. As always, YMMV.

 

Personally, my vote is for the HFC version of whatever brand you're choosing for ecological reasons and just as importantly, to reduce the incidence of boost spike which is dangerous and harmful to your engine

[nm]

you bought the wrong car, you may want to re-consider and purchase a prius....give me a break, tell that to everyone who has a motorcycle or a classic car. You're not doing much harm to our environment running a catless car.

Get over yourself.

Cats are a massive improvement. Removal of HC by almost 300%, CO by over 200%, and NOx by over 350%. And this is versus a dead cat, catless would be slightly worse.

The only reason you can still breathe in Los Angeles is the cat.

Classic cars generally don't get many miles and are of decreasing numbers. Motorcycles are small motors with minimal emissions (however, they are significantly greater than the should be). I'd bet the annual emissions of these groups are less than a week of modern cars before cats. And then there's the fact that you're removing an emissions device where you'd have these people add them. It costs you nothing to keep your function cat. You want something high-flow for perfromance, but you don't "need" it.

What does this have to do with my car choice? I'm not out for the greenest thing possible. With a cat the difference of emissions of these substances is quite minor anyhow. However, there's a line between restricting performance for minimal emissions gain and just throwing the environment out the window. Getting rid of the cat is throwing the environment out the window. It gives you very minimal gains performance gain at little cost. But the benefit to the environment is huge. These are serious pollutants, much worse than the CO2 we worry about today.

I'm all for getting as much as you can out of the car within reason. Put a big-ass turbo on, whatever. But shit, for $100 more you can stick on a catted downpipe and improve the emission fo these extremely harmful substances to a massive extent witha loss of horsepower that's comparable to a dyno's margin of error.

No, you yourself, won't hurt anything to a major extent. But, like everything with strong negative externalities, it requires all of us to particpate. Tragedy of the commons and all that.

[Guest LGT-NY]

^^^

Get over yourself.

[goneskiian]

Get over yourself.

Cats are a massive improvement. Removal of HC by almost 300%, CO by over 200%, and NOx by over 350%. And this is versus a dead cat, catless would be slightly worse.

The only reason you can still breathe in Los Angeles is the cat.

Classic cars generally don't get many miles and are of decreasing numbers. Motorcycles are small motors with minimal emissions (however, they are significantly greater than the should be). I'd bet the annual emissions of these groups are less than a week of modern cars before cats. And then there's the fact that you're removing an emissions device where you'd have these people add them. It costs you nothing to keep your function cat. You want something high-flow for perfromance, but you don't "need" it.

What does this have to do with my car choice? I'm not out for the greenest thing possible. With a cat the difference of emissions of these substances is quite minor anyhow. However, there's a line between restricting performance for minimal emissions gain and just throwing the environment out the window. Getting rid of the cat is throwing the environment out the window. It gives you very minimal gains performance gain at little cost. But the benefit to the environment is huge. These are serious pollutants, much worse than the CO2 we worry about today.

I'm all for getting as much as you can out of the car within reason. Put a big-ass turbo on, whatever. But shit, for $100 more you can stick on a catted downpipe and improve the emission fo these extremely harmful substances to a massive extent witha loss of horsepower that's comparable to a dyno's margin of error.

No, you yourself, won't hurt anything to a major extent. But, like everything with strong negative externalities, it requires all of us to particpate. Tragedy of the commons and all that.

 

Well said.

[holyjoetart]

Uhm, removing cats is illegal under federal law. that means, if Wyoming is still part of the US, it is illegal to run without a cat.

Define "pass"

High-flows will nearly always pass the sniffer test. And even one that doesn't is still polluting less than an open pipe.

 

Then anyone going Stg. 2 with a catted, catless, or gutted DP is in violation of the law.

[korpsepatrol]

Invidia catted is the way i went on my 5eat and what i am planning to go with my 5mt now. Very good power and no tapering to 2.5 like a the cobb dp.

[05gtlimited300]

love my invidia catted DP. perfect fitment, changed the sound a bit and the smell slightly at WOT

[nm]

Then anyone going Stg. 2 with a catted, catless, or gutted DP is in violation of the law.

Big difference between removing and replacing.

Even if you change the cat location (including removing the upipe), you're simply replacing the catalytic converster system. My understanding of the law is that is still legal.

Even if it is illegal, I don't think legality should be the prime mover behind it. It's the drastically reduced emissions.

[QLQ]

I have the Catless version. I love it. If you are looking for maxium flow, then the catless is the way to go. If want an exhuast that is not as loud, won't smell up the cabin with DP smell and will be better for the environment, the Catted version is for you. Catted version is more expensive though.

I already have the same setup!

[holyjoetart]

Big difference between removing and replacing.

Even if you change the cat location (including removing the upipe), you're simply replacing the catalytic converster system. My understanding of the law is that is still legal.

Even if it is illegal, I don't think legality should be the prime mover behind it. It's the drastically reduced emissions.

 

You're not replacing the catalytic converter system, you remove all but one cat by going with a catted Dp. All in all, it is better for the environment to go with a catted DP, I chose not to.

My CEL went away too. Gotta remeber to plug the O2 sensor back in;)