utmost violation of EPA emissions standards

thefunk · **Posted:** Tue Sep 22, 2015 11:06 am

So, if a person had already removed the EGR and done the EHM and wanted to make their vehicle completely out of compliance with EPA mandated emissions requirements and remove the catalyst and muffler as well and replace with a non-restrictive muffler, what kind of power or fuel efficiency gains might one expect? of course that would be illegal and I would never do it, but just thinking theoretically... :wink:

I'm driving to California in December. Can't wait :-)r

Mountainman · **Posted:** Tue Sep 22, 2015 11:28 am

I don't think that there is much to gain with a CAT delete, unless maybe you're going to build it like a race engine with a bigger turbo and bored injectors. But, a strait pipe Cat back like Sasquatch sells for $80 is a nice improvement over stock. I bet you'd get 1 mpg with it, paying for itself in time. Keeping the EGT's lower and the cat cleaner with the extra flow should make it even more worthwhile :2cents:

A lot of us are running the 2.5 cat back, it gets rid of the 2" restriction by the muffler. My magnaflow muffler also flowed nicely.

flash7210 · **Posted:** Tue Sep 22, 2015 11:51 am

Straight pipe, no cat, no muffler:
Allows turbo to spool up faster for slightly better acceleration. No overall gain in power because the ECU limits boost.
MPG gain = 0-1

EGR delete:
Keeps soot from building up and clogging the intake. Eliminates possibility of EGR cooler leak.
No overall gain in power.
MPG gain = 0-2

GDE Full Torque EcoTune:
Re maps fuel injection cycle. Increases turbo boost. Significantly reduces EGR function.
Allows all factory components to be retained for a factory "look."
Unknown CARB smog check performance (sniffer test).
Gain of about 35 ft/lbs of torque.
MPG gain = 3-5

EcoTune + straight pipe + EGR delete:
MGP gain = 4-8

GDE turbo kit:
Huge gain in power.
MPG gain = ???

Quote:

of course that would be illegal and I would never do it, but just thinking theoretically...

Learn from Volkswagen's mistake.
Dont get caught

BTW:
There are free tunes available that help facilitate the deletion of the EGR valve.
Power can be gained from them but exactly how much in unknown.
Same with MPGs, but MPG are more directly related to how you drive.
I drove from FL to CA back in december. Had "Nicks 811 stage 1 tune" loaded throughout the trip. My MPGs were poor. But I was driving 75-85 mph and had my wife, kid, and dog. Plus, about 250 lbs worth of stuff loaded on the roof. Seemed like I was constantly driving into the wind.

jws84_02 · **Posted:** Tue Sep 22, 2015 6:45 pm

I did some cat foolery. I cut it off and then knocked all the baffling out and then welded it back in. lol

I also got rid of the choke point and added a magna flow straight through muffler. It seemed to help with back pressure and coasting farther

thefunk · **Posted:** Tue Sep 22, 2015 7:31 pm

I'd probably do it just for turbo spool up speed alone, I've noticed it lags a bit. I'd definitely put in a low back pressure muffler to kill the noise though, I'm old enough that I'm well past the "loud engine is good" phase. I like to hear my Dire Straits while driving... :rockon:

mass-hole · **Posted:** Mon Sep 28, 2015 12:59 pm

flash7210 wrote:

Straight pipe, no cat, no muffler:
Allows turbo to spool up faster for slightly better acceleration. No overall gain in power because the ECU limits boost.
MPG gain = 0-1

EGR delete:
Keeps soot from building up and clogging the intake. Eliminates possibility of EGR cooler leak.
No overall gain in power.
MPG gain = 0-2

GDE Full Torque EcoTune:
Re maps fuel injection cycle. Increases turbo boost. Significantly reduces EGR function.
Allows all factory components to be retained for a factory "look."
Unknown CARB smog check performance (sniffer test).
Gain of about 35 ft/lbs of torque.
MPG gain = 3-5

EcoTune + straight pipe + EGR delete:
MGP gain = 4-8

GDE turbo kit:
Huge gain in power.
MPG gain = ???

Quote:

of course that would be illegal and I would never do it, but just thinking theoretically...

Learn from Volkswagen's mistake.
Dont get caught

BTW:
There are free tunes available that help facilitate the deletion of the EGR valve.
Power can be gained from them but exactly how much in unknown.
Same with MPGs, but MPG are more directly related to how you drive.
I drove from FL to CA back in december. Had "Nicks 811 stage 1 tune" loaded throughout the trip. My MPGs were poor. But I was driving 75-85 mph and had my wife, kid, and dog. Plus, about 250 lbs worth of stuff loaded on the roof. Seemed like I was constantly driving into the wind.

Agree'd. Without a tune, you wont see much performance increase as the ECU controls boost. No matter what the engine is going to target the same boost level so the only thing you may get is a slight bump from efficiency.

The GDE turbo kit doesnt give you a huge bump in HP but it fattens up the torque curve quite a bit so you get a lot more power across the whole power band.

seawheeler · **Posted:** Sat Oct 10, 2015 6:49 pm

Just finished up installing a magnaflow #11226 muffler and pipe in place of the cat. What a difference in the coasting as jws84 has mentioned. I cut the cat very near the front of it and it looks like a dirty screen in there, how exhaust was getting by is amazing. The magnaflow is a straight through muffler and is not noticeable louder than the stock set up, very happy with that. Also reduced the weight by maybe 30 pounds. We'll see what other differences it make as I get some more drive time.

WWDiesel · **Posted:** Sat Oct 10, 2015 7:51 pm

Any modification to lower the back pressure on the outlet side of the turbo will increase power and lower fuel consumption if you can keep your foot out of it. Another big plus of a low back pressure exhaust system is lower EGT's under high load conditions that is created by the free flowing exhaust out the tailpipe. A diesel engine is basically an air pump, anything you can do to get more air flow in and out of the engine with less restriction will produce more power and better fuel millage... :wink:

No CAT and a free flowing muffler or no muffler are always a plus to a diesel engine...

utmost violation of EPA emissions standards

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