What is the difference in sound between a 4 inch and a 5 inch turbo back exhaust? Also is there much difference in the EGT drop?

Im fixin to have a 4" mbrp put on next week.From what ive read there isnt a whole lot of difference between the 2.

it would help to know what year truck you have but the new lly moter dont like 5in they set a no back pressur code unless you have work done intake chip lift pump just for starters

Thats funny, none of our LLY's set codes with aftermarket/no exhaust. I run a 4" cat delete front pipe, and a 4" 45* elbow on my truck, thats it, and have never set a "no backpressure" (egr) code. I think this is only a problem on the Calif emissions trucks. not LLY's in general.

Now to answer the questio, The 5"'s have a deeper tone. Sounds good. But it depends what you want. If you go to MBRP's webiste they have sound files of most of their exhausts. The 5" will not net much more of an egt drop that a 4" either.

it would help to know what year truck you have but the new lly moter dont like 5in they set a no back pressur code unless you have work done intake chip lift pump just for starters

Any turbo vehicle doesn't need back pressure to run. It is the reason that a cold air/exhaust combo is the best thing for one. Personally, I love my 5" (the turbo downpipe is 4" no matter what-5" cant make the bend). The 4" guys say the same. As far as argument, you would have to find someone that's had both.

my truck is an 03 model so its the LB7 motor so it shouldnt have any problems with the error code

I get nothing but compliments on how my 5" sounds. Not to mention the size of the pipe blows peoples minds. It's not loud in the cab like you would think. My truck came with a 3.5" straight pipe, and is quieter now than it was then. It's a little deeper with a lot better tone.

Thats funny, none of our LLY's set codes with aftermarket/no exhaust. I run a 4" cat delete front pipe, and a 4" 45* elbow on my truck, thats it, and have never set a "no backpressure" (egr) code. I think this is only a problem on the Calif emissions trucks. not LLY's in general.

Now to answer the questio, The 5"'s have a deeper tone. Sounds good. But it depends what you want. If you go to MBRP's webiste they have sound files of most of their exhausts. The 5" will not net much more of an egt drop that a 4" either.

It's hit and miss. Some do some dont. My truck is an FE9 and when I pulled the cat it set a code. Had to get the blocker plate and Finger Stick.

I have the 5" cat-back from MBRP on my 01 LB7. I've heard both the 4 and 5 inch and I would have to say that the 5 inch is the more throaty of the two. Mind you it is a little loud so if you aren't loooking to wake the neighborhood the 4 inch is the way to go.

There wont be a significant drop in EGT from 4-5, but from what I have heard with my own ears, five inch has been considerably louder than the four. On the other hand, four inch systems both on here and from what I heard first hand are often times too quiet.

has anyone straight piped an lb7 with 5in?

I think I have seen video clips here in the video archive.

has anyone straight piped an lb7 with 5in?

I've never thought to do it. I have enough pipe that I could, though. I would imagine that it would almost sound the same b/c you can see all the way through the 5" muffler anyways(it's wide open).

well i'm wanting somethin that is a somewhat loud but not obnoxiously loud. also i want to keep the cab noise to a minimum

i have complete straight pipe lb7 no cat or muffler... used to have muffler reversed then ordered a delete pipe. WOW!!! what a difference. It roars esp. around 2100-2200 rpm's *slight drone and resonance* some like it some dont... to each his own i guess

WOW!!! what a difference. It roars esp. around 2100-2200 rpm's *slight drone and resonance* some like it some dont... to each his own i guess

Exactly, my truck is the same way...alot of people think its to loud but I love it. Like you said about 2100-2200 is the sweet spot...just makes you :D everytime.

Cheyenne19 has a 5" straight piped. He loves it. I have the same exhaust with a muffler and I love it. I don't want to neighbourhood to think a dump truck is driving around, so I am keeping the muffler. 5" is the way to go.

i have had both cool dual and 5 inch mbrp and am selling my cool duals to reinstall my 5 inch i have seen a rise in egt of maybe 100 degrees or more and its sounds basically the same as the 5 inch just quieter. i thought my five inch was too raspy but now i miss it but there is drone with my five inch and none with the cool duals which flow almost equally to a single four inch setup.

Bigger is always better.:D
you can always stick a smaller muffler on if you dont like it.:confuzeld
i am very happy with mine.

I have a 4 in turbo back Expandit in mine and it's not very loud-no drone at all, nice turbo whistle-albiet nothing like a 6.0 Ford.
Very pleased-esp for the $ -- I'm fairly sure it's the cheapest one made. Quality was good, install was easy. They even included a muffler delete pipe and several extra brackets.
$.02

i was looking at the expandit kit..... does it go together easy. i am a little worried about the quality. there kits are cheap

The fellow that I bought it from a "supporting vendor" is a MBRP and Expandit dealer, he said the build/install quality is the same. Good stuff. Kennedy said it was good as well when someone was being negitive about them. I installed it and it was easy. Real easy, of course I used the local Hummer dealer's lift. I'm in Memphis, no salt just rain--so I didn't go with Stainless, I'm not building a show truck, just one that hauls butt.