Question: Whats this guy talking about

[speedmetal6.6]

I was told buy a tech rep of a rather popular diesel performance company that shall remain nameless that I lost horsepower buy taking off my catalytic converter by going with a turbo back system, He siad " that's why we sell them cat backs " I guess he was refering to D-MAX guy's. Is this guy full of it or should I have went with a cat back system. P.S. I was wondering if maybe you guy's had a good guess on how much HP I might be running based on the mods I have, I havent had the chance to get it on a dyno.( thanks)

 

[NelsonDiesel]

opinions are like assholes, everyones got one.....


some are better then others and this one is gibberish.


I would save my money for somewhere else.



catbacks are for "on-road" guys. deleting the cat is for off road guys because you are supposed to leave emissions on.

 

[McRat]

I was told buy a tech rep of a rather popular diesel performance company that shall remain nameless that I lost horsepower buy taking off my catalytic converter by going with a turbo back system, He siad " that's why we sell them cat backs " I guess he was refering to D-MAX guy's. Is this guy full of it or should I have went with a cat back system. P.S. I was wondering if maybe you guy's had a good guess on how much HP I might be running based on the mods I have, I havent had the chance to get it on a dyno.( thanks)

As far as the cat goes, you might see a minor gain removing it. The real restriction is the muffler. But lose power? Nope. Not on a dyno or the track.

 

[McRat]

I would guess about 400rwhp, but am not sure.

 

[LWATSON]

I have been thinking about removeing my cat, is it worth the power gain or does it really not effect flow much?

 

[The Neens]

I have been thinking about removeing my cat, is it worth the power gain or does it really not effect flow much?

I've removed one and held it up to the big fireball...Could barely see daylight, I'd remove it...

 

[McRat]

In case the EPA is reading this board:

No, never remove any of your emissions controls, as it will hurt your performance and you could be given the death penalty if we catch you.

In case they aren't:

It will lower your EGT's and IIRC, is worth about 5 rwhp at the 450hp level. The more power, the bigger the gain. But removing it with the stock muffler in place will do nothing either way. It's the muffler that's really the problem. Most states do not have emission tests for diesels, so you are safe.

 

[speedmetal6.6]

Thanks

I knew that guy was talking garbage, it wasn't the first time I was misled by that company( and they call themselves #1 in diesel performance HA!! thats a load of sh#t) thats why I sold there tuner and have since gone with PPE products, but I'm curious about this EFI live stuff

 

[LBZ]

The weight savings by removing the Cat and Muffler are a bonus as well!!

 

[DieselDaze]

In case they aren't:

It will lower your EGT's and IIRC, is worth about 5 rwhp at the 450hp level. The more power, the bigger the gain. But removing it with the stock muffler in place will do nothing either way. It's the muffler that's really the problem. Most states do not have emission tests for diesels, so you are safe.

Refresh my thought process again please, what exactly does egt, and iirc stand for? delete the muffler altogether or aftermarket?

I remember back in the day my old truck ran like crap and it was the cat, punched a hole through it with a broom stick and it ran fine.

 

[LBZ]

Refresh my thought process again please, what exactly does egt, and iirc stand for? delete the muffler altogether or aftermarket?

I remember back in the day my old truck ran like crap and it was the cat, punched a hole through it with a broom stick and it ran fine.

EGT=Exhaust Gas Temperature
IIRC=If I Remember Correctly

 

[whitetrash21]

Try running a decent tune with the cat in. Every now and then, I'll lay into particularly hard and get a shower of sparks firing out the exhaust from the buildup breaking loose in the cat.... Really should get rid of it but Nevada (particularly Clark County) requires an emissions check for any diesel under 10k gvw... Truck wont pass visual without it.

 

[LBZ]

I remember back in the day my old truck ran like crap and it was the cat, punched a hole through it with a broom stick and it ran fine.

... Truck wont pass visual without it.

With this technique, you will Wes!!

 

[TannerJP]

It's probably bull in your case, but there ARE some cases where the additional backpressure allows for better exhaust characteristics and more power.

The only case i know of for sure was on a 2003 SVT cobra. They did bolt on type mods (pulley, etc). For whatever reason, it made more power (according to area under the curve, but not peak by a small margin) with the stock exhaust and a cat delete vs a larger aftermarket one.

So they still removed the cat, but the stock diameter made more power than an larger one did.

 

[whitetrash21]

With this technique, you will Wes!!

Next truck I'll do that to.... This one's going byby soon I hope.

Emissions ppl around here are weird. One place did a visual, another didn't. That one basically told me that as long as the truck can hold 40 mph for 10 seconds and not smoke, I'll pass. I think it's all bullshiz... GVW should be dropped to 8500 so all 3/4 and up trucks dont need to smog. I guess those days are long past.....

 

[LBZ]

GVW should be dropped to 8500 so all 3/4 and up trucks dont need to smog. I guess those days are long past.....

More than likely, the GVW will go up to include the big trucks as well.

 

[whitetrash21]

More than likely, the GVW will go up to include the big trucks as well.

I figured as much would happen. I came from cali though, the most commie state in the USA, and even THEY didn't have this BS law. It's all downhimm from here....

Oh well, smokeless diesel only gives the ricers something to really scratch their heads about....

 

[bonescarolfi]

If you have to pass a visual inspection you could cut the cat apart and pull the guts and and re-weld it. Just make the welds look good. When I was in high school a lot of kids did it cuz they were worried about getting caught without it even though central Wisconsin doesn't do emissions testing of any kind.

 

[LASTMIKE]

big trucks have to do opacity tests to measure how much soot is emitted out the pipe, I do a lot of these tests at work. I guess you could call it emissions testing!

 

[The Neens]

If you have to pass a visual inspection you could cut the cat apart and pull the guts and and re-weld it. Just make the welds look good.

This is what we did on my buddy's '07...Cut it open on the body-side of cat, gutted, welded back together...