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Reign in Blood
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Discussion Starter #1
I just picked up a 2004.5 2500HD with 207,000 miles on the clock. Runs great, body and frame are perfect, new injection module, 2 new injectors, etc...I have been looking at threads on here and really like the mouthpiece upgrade. As far as exhaust, I have an OEM stainless setup that is in great shape, I am thinking of just removing the muffler to add some flow to it. I am also looking at a banks intake.

I'd love to throw a 6 gun on it but with 207k on it, I really don't need to push my luck.

What do you guys think about the exhaust mod? Yes I am aware of the downpipe shape...or misshape and DPF being a bit of a cork. I am really just looking for some extra MPG, maybe a little extra noise ;) if I want to go fast I drive the 07 imp SS :thumb:
 

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1. do the mouthpiece
2. don't waste your money on banks
3. you don't have a DPF. you have a catalytic converter and a cat. i'd recommend a downpipe and straight pipe system
4. 265/75/16 or 255/85/16 tires aired way up
5. clean your MAF
6. look into doing the LBZ air intake swap when you do the mouthpiece as it is a much better design or just buy a CAI
7. use a fuel additive to make up for the lost lubricity in ULSD. diesel kleen is popular. i run XPD Summer lube + 2 stroke TCW-3 oil
8. get gauges with an egt probe. i suggest edge CTS insight. keep boost as low as possible. boost gauge is a reverse mpg gauge. higher the boost the worse the mpg's.
9. get a ridiculously good mileage tune from one of the respected EFI tuners. Rob/Nick/etc.
 

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Defiantly upgrade your mouthpiece. For the price you can get a 4" exhaust for, I would say just go aftermarket, getting rid of the muffler may help a little, but the catalytic converter is a big restriction as well. Instead of the six gun, get EFI Live/pretuned ECM - If you choose the right place to get it from, it will treat you better than anything else out there.

Just some thoughts!
 

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Reign in Blood
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Discussion Starter #5 (Edited)
Luckily I am in NJ, no inspection for my vehicle weight class + diesel. If I got rid of the cat would the truck throw any codes?

it has new 265 75 16 tires on it, but like i said, the programmer can wait. I am looking for bang for your buck type things...which usually leads to me just buying the high end stuff anyways.
 

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Luckily I am in NJ, no inspection for my vehicle weight class + diesel. If I got rid of the cat would the truck throw any codes?
Most of the time it won't, but there is a small possibility it will. I don't think I have every heard/seen an LLY throw a code for that.
 

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Reign in Blood
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Discussion Starter #7 (Edited)
so what are some of the better intakes to get? Do they increase spooling noise? How about exhaust...I am looking at MBRP, but also have seen diamond eye...any other suggestions?
 

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so what are some of the better intakes to get? Do they increase spooling noise? How about exhaust...I am looking at MBRP, but also have seen diamond eye...any other suggestions?
MBRP Exhaust. S&B intake. You will hear your turbo more with an intake.
 

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Reign in Blood
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Discussion Starter #9
MBRP Exhaust. S&B intake. You will hear your turbo more with an intake.
call me childish...but that turbo sound just rustles my cockles every time :D
 

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One more thing, look into an EGR Blocker plate.(will in most cases throw a code, but I suggest you do it, code can be turned of with programmer)
 

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Reign in Blood
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Discussion Starter #11
ok after some research here and there I have come up with the following modifications:

afe mouthpiece
MBRP 5" straight exhaust, turbo back
S&B intake system

Now for the big question...does anyone have an idea on mpg/hp/tq gains this combo will produce? My guess is around 2-3 mpg, 40 hp, and around 100 ft/lb.

thanks for the time
 

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Im getting between 24 and 27 with my mods on my 05 rclb lly


Sent from my Autoguide iPhone app
 

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ok after some research here and there I have come up with the following modifications:

afe mouthpiece
MBRP 5" straight exhaust, turbo back
S&B intake system

Now for the big question...does anyone have an idea on mpg/hp/tq gains this combo will produce? My guess is around 2-3 mpg, 40 hp, and around 100 ft/lb.

thanks for the time
what do you get stock mpg?
i have lly and i get almost 17. what do you get stock?
 

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Reign in Blood
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Discussion Starter #14
around 16ish
 

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I have a 4" down pipe back exhaust, no cat. Also the AFE stage II intake. I noticed no difference in HP or mpg with this mod.
I have recently installed the AFE mouthpiece. I did notice a gain in HP but not much if any in mpg. Maybe .5 to 1 mpg. So little it's hard to tell.
I'm getting 17 to 18 hwy at 70 mph. 15 to 16 in town. All depends on how I drive.
I ordered a PROFAB down pipe and EGR delete today. Plan on installing this weekend. I am curious if I will see gains in mpg. From all I have read I will see HP gains.
Also ordered EFIlive. Probably won't have it installed for 2 weeks.
 

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I get 15-17 in town. 18-21 hwy with efi set on top setting.
 

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Reign in Blood
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Discussion Starter #18
just ordered the afe mouthpiece and 5" SS MBRP turbo back straight pipe kit...sweet
 

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Profab down pipe installed today. A lot easier than expected. Only prob was the tranny Dipstick tube. Getting it bolted up right. It is up against the downpipe. Hope temp isn't a problem. Got it installed in less than 2 hrs. EGR delete tomorrow.
 
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