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Discussion Starter #1
I've been reading for the last couple hours about tuners, and exhaust.
There is A LOT to read.
truck is currently stock
My first priority is increasing economy (hand calculated best of 16.3mpg 100% highway)

Originally, I thought I would get a tuner, and see what that did.
Now that I've been reading, it looks like tuners will bump up my EGTs, and Boost, so I would need gauges to monitor that, in my opinion. I had been looking at the Quadzilla stealth, but now I read about some convertor shake with them? Adding a tuner, and having to worry about all these other things isnt really okay with me.

Then I started considering exhaust. I read that people see a decent boost in MPG when the cat, and muffler is removed. This concerns me, because I sure don't want a loud truck. I have a loud malibu, but for my daily driver, I'm not trying to wake up the neighborhood. This is where my diesel ignorance maybe getting me. I know that the turbo itself muffles sound.
Basically, my question about exhaust is, how much louder (if any) would the truck be with no muffler/cat.
With a straight exhaust, would it through codes for any reason?

I'm not new to performance, and turning wrenches, just knew to diesels, and a computer controlling everything the truck does.

I've got about $400 to spend, and don't know what to get. It looks like with that cash, I could get either the exhaust, or a tuner.

This morning it went from want one thing, to needing Tuner, Exhaust, trans-go-jr, gauges.
:rolleyes:
 

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Installed a 4" MBRP straight on my stock LBZ a couple of weeks ago.

In the cab while at cruising speeds, you cant even tell that it has a straight pipe (still sounds like it has a cat and muffler until you hit about 70ish it gets a little noisy, but not bad). And yes it is considerably loud when you accelerate quickly or stand on it IMO.

No codes from removing cat/muffler.

Not sure how I went 6 months without the straight pipe. Love it!
 

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Discussion Starter #4 (Edited)
Installed a 4" MBRP straight on my stock LBZ a couple of weeks ago.

In the cab while at cruising speeds, you cant even tell that it has a straight pipe (still sounds like it has a cat and muffler until you hit about 70ish it gets a little noisy, but not bad). And yes it is considerably loud when you accelerate quickly or stand on it IMO.

No codes from removing cat/muffler.

Not sure how I went 6 months without the straight pipe. Love it!
What do you love about it? Just the sound? Sound is the least of my concern. edit* keeping the sound down IS a concern. How "sporty" it sounds, I couldn't care less about.

exhaust (cat delete) first mod hands down.
Removing only the cat, and keeping the muffler will keep noise down, or probably the same as where it's at now?
 

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Its depends what u want you can cut ur cat out an leave the muffler, or buy system and still have stock truck. I would get a tuner
 

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I installed a 4" mbrp cat delete with muffler a few weeks ago.

How anyone can say these arent any louder than stock is beyond me and Ive heard this a lot.

They are louder in all areas of driving.

I love the tone at idle and city cruising and it seems to have a louder turbo whine also which I like, mild drone/noise at hwy speeds, 60mph+.

Like you I was after fuel economy, though I have yet to test my mpgs for a full tank because Ive been laying on it every now and then. :)

The one week I did go easy, the gains were minimal if any at all.

The verdict is still out if I'll see better mpgs or if the wife and kids will mind the noise on long camping trips.

Looking at what your after and not after, I wouldnt spend your money on a new exhaust system, rather just delete the cat and replace the front pipe with a 4" front pipe from mbrp or a quiet tone front pipe from diamond eye.
You'll need a reducer pipe from the 4" front pipe to the factory 3" pipe.

Someone in the LBZ section did this, I'll have to see if I can find the thread for you.
 

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I would either do a new exhaust of modify your stock before adding tuning. It is better to open up the exhaust and let it breathe before you add tuning. A exhaust alone won't give you any real noticeable mileage gains. However if you add a programmer you can see 2-3 mpg increase.
 

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I was in the same position as you because I was afraid of how changing the exhaust would sound. I had my local shop cut the cat from my stock exhaust first before I got a full 5" MBRP. I currently have no radio and the exhaust is not that loud in the cab. My grandma didnt even think it was annoying when I drove the family to dinner. I have seen guys on here piece together a Diamond Eye exhaust system for under $400 but I doubt you will get a tuner for that money unless you check craigslist.

I never threw a code when my cat was deleted but I read there is a code to check in the glovebox that helps indicate if you would or not. If you would throw a code then you need an Edge or EFI tuner that could clear it. I think PPE also deletes codes but I am not sure on Quadzilla.

*I am a noob also but this info may help you ask better questions to more knowledgable people
 

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In the original post you were concerned with the sound of no cat/muffler. I was just giving you my opinion on what a straight sounds like. I can tell you I saw minimal change in mileage with just an exhaust. From what I can tell in order to really gain mileage you need a tune AND exhaust as they work hand in hand with each other. You may get online and just listen to some exhaust to find your best fit.

If you want to keep it quiet, a straight pipe is def. not the route to take. It sounds like you need to keep a muffler if you want to stay quiet. Hope this helps and good luck with what you decide on! :drink
 

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Discussion Starter #10
In the original post you were concerned with the sound of no cat/muffler. I was just giving you my opinion on what a straight sounds like. I can tell you I saw minimal change in mileage with just an exhaust. From what I can tell in order to really gain mileage you need a tune AND exhaust as they help each other out. You may get on online and just listen to some exhaust to find your best fit.

If you want to keep it quiet, a straight pipe is def. not the route to take. It sounds like you need to keep a muffler if you want to stay quiet. Hope this helps and good luck with what you decide on! :drink
yea, I hope my phrasing of the question didnt make me sound like a dick, it was a serious question. I'm thinking cat delete with a packed muffler, and a tuner first.
 

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Nope understood completely what you meant, and didnt think you were being a dick..
 

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I went with a 5" Flo-Pro SS Exhaust with a Diamond Eye Downpipe on mine, and as far as cranking up and driving around a neighborhood type setting it is very quiet and mellow. A nice low rumble(far from loud or offensive). I left the Flo-Pro high flow muffler on which I think keeps it down a bit, but the kitty is gone. The DP seemed to open it up a bit more and give it that throaty sound that sounds a bit more mellow than some of the other just straight piped exhausts I have heard. You cant go wrong with an exhaust thats for sure. Though with upgrading the exhaust no matter the size or brand when you stand on it, it will talk back and it will be heard.

just my 2 cents :)
 

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Convertor shake and what not is from the people running high hp tunes and are beating on them. A quadzilla on a low setting will be fine. Your egt's will stay in check unless your going crazy pulling a hill with a trailer.
 
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