So I've been looking into getting a mbrp exhaust, they offer 4 an 5 in exhaust. Wouldn't the 5 in. be better for more flow??? And I'd like to get the one that is from the turbo back plus I'd like to run the straight pipe w/ no muffler. Do the lbz's throw any codes when you get rid of the cat an muffler?? Also would this exhaust work well with banks products, I don't really care for the small 4 in. exhaust that banks has?? Thanks for any input you guys can give me

while you all are at this question, i too am interested in an exhaust system to improve tor/hp. i pull a 5th wheel.

i would also want a "quiet" system. in the past i put a flowmaster on a gas truck and it was terribly loud.

Gas and diesel sound completely different. Diesels dont tend to drone like the gas counterparts.

A straight piped 4 or 5 inch is going to be loud,the 4 inch will give good flow characteristics.Some have reported a loss of low end torque with the 5 inch.As for pulling a fifthwheel quiet is better and the stock exhaust works very well,not much to be gained power wise or for mpg.I have a 4 inch cat back which makes a little more noise than stock but did nothing to reduce EGTs,no mpg gain and no power increase.Getting rid of the cat and muffler will reduce EGTs but will be too loud for most people.

I have installed MANY 4in and 5in over the counter systems and hand made custom systems of both sizes. The 5in gives a nice tuned mellow sound as opposed to the 4in IMO. 4in tends to give a raspy poping sound when accelerated hard. Unless your making considerable power, there is little to be gained by going to the 5in over the 4in. Different manufactures have drastically different sounds to their muffler options and styles. For the quietest systems I've used Magaflow's universal 4in/out mufflers and installed them in other's systems b/c they work well and are very quiet. Banks makes a very quiet system also. I do believe there are egt losses experienced with any free flowing system over stock. Especially when the cat is deleted. The factory muffler is very inefficient, but the quietest you will find, due to its flat 360degree internal design. BTW, certain systems will give you a drone epsecially those used on LB7's.

I had a mbrp on mine. Heard aREAL ANNOYING sound in my right ear. :DFound a magnaflow muffer to replace and the sound has since disappeared. I like it better too. The mbrp was too loud for me, especially when pulling my camper. Corsa is the closest to stock as far as aftermarker goes, but you better get your wallet out.

i have the MBRP stainless 5in turbo back with no cat or muffler and the mbrp 3in downpipe. the downpipe gotrid of the loud wooshing sound at high boost in the LBZ and gave it a deeper meaner sound. the whole setup isnt really that loud in my opinion but my last truck was an 03 dodge with straightpipe and 6in stacks. i can still talk on the phone and its not annoying by any means. some say you wont see a power gain from 4 to 5 unless your over 500hp but i just like the look and the deeper tone of the 5. im completely happy with my setup, the tires are louder than the exhaust on the highway but when you get on it people notice :) oh and yes it will throw codes as soon as you loose the cat but nothing a finger stick wont fix

i have the MBRP stainless 5in turbo back with no cat or muffler and the mbrp 3in downpipe. the downpipe gotrid of the loud wooshing sound at high boost in the LBZ and gave it a deeper meaner sound. the whole setup isnt really that loud in my opinion but my last truck was an 03 dodge with straightpipe and 6in stacks. i can still talk on the phone and its not annoying by any means. some say you wont see a power gain from 4 to 5 unless your over 500hp but i just like the look and the deeper tone of the 5. im completely happy with my setup, the tires are louder than the exhaust on the highway but when you get on it people notice :) oh and yes it will throw codes as soon as you loose the cat but nothing a finger stick wont fix

This is the exact kit I have been looking at. So pretty much a 5in. exhuast is just for looks and sound no power benifits? Also how did you get rid of your codes, what do you mean by finger stick?? Thanks

5" is for looks and sound alone. If you get codes you can do a fingerstick or purchase a tuner that takes care of them also.

I just went from a 4in straight to a 5in straight it sounds better than the 4in but thats it no power gain i just wanted the deeper tone

I have the 4" MBRP TurboBack Cat delete.

No MPG gained. No power increase.

It has a throaty sound to it, but it does (in my opinion) have a slight drone.

5" is for looks and sound alone. If you get codes you can do a fingerstick or purchase a tuner that takes care of them also.
What is a fingerstick??? Also do you happen to know if the banks programmer can eliminate these codes? And with a straight pipe this will not pass smog correct? Thanks

its made by kennedy diesel. it blockes the codes thrown by aftermarket intakes and exhaust. the computer thinks you have a leak when you put on higher flowing parts. the stick limits the sensor readings so you do not get any codes. i have the insight so i could clear codes at any time but if you ignore it there could be more serious codes than MAF codes there and you wouldnt know about it. i recomend it and its very reasonlably priced. for more info do a search, there is tons of info and installs on these. im not for sure on the smog test as we do not have them here in the boondocks but i would assume it would not pass. yes 5in is basically just looks and tone, you will not see a greater drop in EGT's VS. a 4in, any it doesnt flow much more. (there are 600-700rwhp trucks running 4in exhausts)

I just went from a 4" cat back to 5" turbo back with no muffler. 5" is considerably louder and does have a drone at exactly 70 mph. Anything below 70 and it's quiet inside the cab. I love the new sound though! No power or mpg difference.

This is one of my pet peeves. There is no such thing as a "Turbo Back" 4" or 5" exhaust system. In truth, they are "Downpipe" back systems. You have to actually install an aftermarket downpipe in order to have a true turbo back system. Even then, the only aftermarket downpipes on the market that I know of are 3" dia as there is simply not enough room between the firewall and engine for anything larger. So keep in mind if you choose to install a downpipe you will be connecting your 4" or 5" exhaust to a 3" downpipe.

Moved to Fuel System, Air, Exhaust, & Emissions Upgrades.

I have a mbrp downpipe and 4" straightpipe. Turbo spools a lot faster, cooler egts and sounds great. No more high pitched scream with the downpipe. I felt a difference in power. More flow=more power. jmo and butt dyno!

The JDMan makes a very good point as to the 3 inch factory downpipe being the bottle neck in the system and no room for anything larger.I think most of the exhaust hype is just that,hype with little to be gained except for a thinner wallet and maybe a nice looking exhaust tip.

What is a fingerstick??? Also do you happen to know if the banks programmer can eliminate these codes? And with a straight pipe this will not pass smog correct? Thanks

Banks is not able to block the codes.

4" is all you really need, but 5" does look and sound great. 5" isnt for everyone though, especially those who tow. It can get a bit annoying on long road trips. If you want the exhaust sound deep and loud, go with 5". If you want a nice low rumble go with 4". If anyone would like more info or a quote, feel free to shoot me a PM. We have some excellent deals on MBRP and Magnaflow kits right now.

Ya I know about the downpipes and all that. So if I go with an entire straight pipe option what system will work best to clear that code?