High Flow Cat - Page 2

LadiesMan217 · November 2nd, 2009, 09:42

Quote:

Originally Posted by Bob_Fout

Just a cat and muffler. You can opt to replace the muffler with a resonator (high-flow resonator?) to tone down the harshness.

Stock is 2.0 or 2.25 inches.

Hmm, the muffler im looking at starts at 2.5 so they should be able to work that on correct? Guess i should spring for the aero resonator/muffler as well, i hate droning. All the reviews ive found on it are positive, not one negative thing.

silverbox · November 2nd, 2009, 12:19

I have the aero 2525xl 2.5 Turbo back with a magnaflo cat
It's not much louder than stock.

LadiesMan217 · November 2nd, 2009, 18:32

Quote:

Originally Posted by silverbox

I have the aero 2525xl 2.5 Turbo back with a magnaflo cat
It's not much louder than stock.

No drone w/o ithe resonator? I assume your cats a high flow, any mileage change from stock?

shizzler · November 3rd, 2009, 05:49

The muffler is not what controls the drone. It's simply the placement and direction of the exhaust tip. A 90 degree turn down inside the bumper is going to drone like crazy, anything pointed out the back of the vehicle will not. No matter whether there is a muffler present or not. Screw a pricey aero muffler, a $20 piece of straight pipe can be totally quiet too.

A turbo and CAT are all the noise attenuation needed.

NewbeeMC9 · November 3rd, 2009, 07:19

Here are some universals from Jegs that might offset your cost,

http://www.jegs.com/p/Magnaflow/Magn...63223/10002/-1

This might be easier to justify and I'm not sure if a diesel cat is different from a gasser.

When it comes to economics, there are different ways to look at it,

-Direct- Cat cost X dollars and will save me X dollars in fuel. I think there is still too many variables, like the driver, etc., for this to be a real process decision. Part of the fun is trying to get more MPG, so what is the cost of the lesson?

Also if only saving fuel dollars is the goal, selling the vehicle will buy a lot of bus tickets or a nice bicycle. You get the drift, still your decision for your pocketbook.

LadiesMan217 · November 3rd, 2009, 09:08

Quote:

Originally Posted by NewbeeMC9

Here are some universals from Jegs that might offset your cost,

http://www.jegs.com/p/Magnaflow/Magn...63223/10002/-1

This might be easier to justify and I'm not sure if a diesel cat is different from a gasser.

When it comes to economics, there are different ways to look at it,

-Direct- Cat cost X dollars and will save me X dollars in fuel. I think there is still too many variables, like the driver, etc., for this to be a real process decision. Part of the fun is trying to get more MPG, so what is the cost of the lesson?

Also if only saving fuel dollars is the goal, selling the vehicle will buy a lot of bus tickets or a nice bicycle. You get the drift, still your decision for your pocketbook.

Thanks for the advice, mainly im looking at it for sound and maybe better mileage. All the reviews ive ever found on it are excellent and many claim better gas mileage too (gas and diesel). So yea if i get better mpg i'll let you guys know, if not i'll still let you know.

LadiesMan217 · November 3rd, 2009, 09:26

Quote:

Originally Posted by shizzler

The muffler is not what controls the drone. It's simply the placement and direction of the exhaust tip. A 90 degree turn down inside the bumper is going to drone like crazy, anything pointed out the back of the vehicle will not. No matter whether there is a muffler present or not. Screw a pricey aero muffler, a $20 piece of straight pipe can be totally quiet too.

A turbo and CAT are all the noise attenuation needed.

Cant quite say i agree with that. For one, the tip on the muffler already is at 45 degrees and who really has a 90 degree downturn on their muffler, i dont recall even seeing any tips like that, not the best for flow anyways, and two, then i had my Pontiac i had the tips strait out past the bumper and i had alot of drone. Thats just my experience with drone, i dont want it, i hate it and i'll do whatever to get rid of it.

shizzler · November 3rd, 2009, 09:44

Yeah, I may have over-simplified. But my point was to get the tips pointing past the bumper valence. The drone (on TDIs) is caused by reflected soundwave from the ground hitting the underside of the rear end. Not much is radiating away from straight pipes. I went from a totally stock exhaust to a mufflerectomy and was quite dissapointed that my sound level didnt change one bit (other than a little bit of turbo wooshing during shifts, which sounds awesome).

But every single Pontiac I have ever seen has droned... Part of that "driving excitement" custom sound, I guess. Most sound terrible (no offense).

shizzler · November 3rd, 2009, 09:53

Oh, and stay away from those converters on Jegs. You need to get one that is diesel specific. This is what you want if you decide to upgrade:
http://www.performancepeddler.com/de...T_ID=MAG93006D

And don't be shy when they ask you to put in a price offer! Absolutely the best deal on the web that I could find.

My personal opinion is that the first bend of the downpipe after the turbo also offers serious exhaust flow restriction. I did the downpipe and the CAT upgrade at the same time, so I can't separate the effects, but together notice a serious mileage difference. I had to go back to my stock downpipe / cat temporarily and the difference looks like about 2 mpg (50 vs. 48 for my normal commute).

LadiesMan217 · November 3rd, 2009, 12:14

Quote:

Originally Posted by shizzler

Oh, and stay away from those converters on Jegs. You need to get one that is diesel specific. This is what you want if you decide to upgrade:
http://www.performancepeddler.com/de...T_ID=MAG93006D

And don't be shy when they ask you to put in a price offer! Absolutely the best deal on the web that I could find.

My personal opinion is that the first bend of the downpipe after the turbo also offers serious exhaust flow restriction. I did the downpipe and the CAT upgrade at the same time, so I can't separate the effects, but together notice a serious mileage difference. I had to go back to my stock downpipe / cat temporarily and the difference looks like about 2 mpg (50 vs. 48 for my normal commute).

Wow thanks for the information. Apparently the guy over at Alligator tuning seems to think that the h/f cats help also. He says his customers who have done it see 1-2mpg increase. Sounds good to me. I would do the downpipe but its too expensive right now.

shizzler · November 3rd, 2009, 13:18

No problem. Just thinking about it more, it would be kind of annoying to try to fit a 2.5" CAT into the stock exhaust system (stock pipe ID is around 2 1/8", i think magnaflow also makes a 2.25" diesel converter).

Also! If you don't upgrade the piping, be aware that the stock cat entrance and exit piping is not linear! It comes in high and exits low. So that could be pretty tricky also.

FYI, there is a guy selling a used downpipe AND cat in the classifieds right now. reasonable price.

kwong7 · November 5th, 2009, 08:54

I'm thinking about doing the mufflerectomy with a new Magnaflow diesel cat. With 198K miles on my stock cat, I feel like my TDI is getting stinkier than before. Perhaps I should have an emissions tech take a look. While I care about the environmental impact of my car, I'm also concerned about my personal health as well.

LadiesMan217 · November 5th, 2009, 09:23

Quote:

Originally Posted by kwong7

I'm thinking about doing the mufflerectomy with a new Magnaflow diesel cat. With 198K miles on my stock cat, I feel like my TDI is getting stinkier than before. Perhaps I should have an emissions tech take a look. While I care about the environmental impact of my car, I'm also concerned about my personal health as well.

At that mileage, if it were me i would just have it replaced. My experience with cats is that they usually dont live to long past 150k(with gassers anyway). Im from SoCal and i dont miss their emissions BS, glad i left that state. The funny thing is that that state has the toughtest emission standards and the worst air quality ..

kwong7 · November 8th, 2009, 11:37

Quote:

Originally Posted by LadiesMan217

At that mileage, if it where me i would just have it replaced. My experience with cats is that they usually dont live to long past 150k(with gassers anyway). Im from SoCal and i dont miss their emissions BS, glad i left that state. The funny thing is that that state has the toughtest emission standards and the worst air quality ..

I'll probably have the cat replaced by the end of the year (along with all my other things for my upgrade overhaul). As for California, yeah it's a funny thing. Seems like the majority of emissions come from the ports, trucking industry, air traffic, and the wonderful traffic congestions that plague the roads and freeways. From all the studies I've read, it seems like the money and efforts to reduce pollutants are aimed at the less significant sources.

LadiesMan217 · December 9th, 2009, 00:40

Well guys its been two fill ups since i installed the Aero muffler and i can proudly say that im getting exacty 2 mpg better than the stock muffler. Well worth the money in my opinion and better yet it sounds exactly stock no drone.. nada.