Engine/Transmission (1998.5 - 2002) 4" Exhaust "Do ya or don't ya"

[BBettencourt]

Hey guys,

An exhaust question. I’m a 99 Ram/4X4/2500 (2nd generation (I guess)) ExtCab/LWB/All White/Leer Shell/Automatic/K&N Filter/PowerEdgeEZ /93. 55's originally 4:10's). No other modifications. How much and what type of benefit will I get by going to a 4" exhaust? Will I need gauges or any other mod then? Is it worth doing? Thanks again for all your input.



BBettencourt:

 

[RustyJC]

Bob,



I went with the 4" exhaust primarily to help with EGT's when towing - we pull a 13,500 lb 5th wheel that puts us at 21,180 GCW (21,500 GCWR). With the EZ (with boost elbow), BHAF and 4" exhaust, maximum pre-turbo EGT's have dropped from 1300 degF to 1100 degF - most of that is due to the boost elbow.



For a stock or lightly modified engine, I don't think your SOP (seat of the pants) dynamometer would even notice the difference. The 4" exhaust with 5" tip certainly looks "right" under our 3500, though!



Rusty

 

[AggieJustin]

The 4" does help drop the temperatures. Since I've put in the 4", I haven't seen temps over 1100. I also picked up a couple of more pounds of boost after it was installed.



But the biggest benefit is the sound... .



And the looks of the 5" tip hanging out in the back.



JM

 

[joshuajackson]

After researching this myself and talking to another TDR member, I installed a straight through 3" system (no resonator or muffler). This helped with EGT, gave better sound, and when I put the EZ, it really woke up. If I were to do it again, I'd leave the resonator in.



Unless you are going to upgrade to a larger turbo housing, I don't see much reason to install a 4" when a few pieces of 3" pipe and a few minutes at a local muffler shop can fix this for you. You can only get some much hot air out one little hole at a time. If you don't want the sound, you could just install a straight flow muffler for similar results. It's all up to what you want to spend.



If you will be changing to a 14 cm housing, then I'd definitely put in a 4" exhaust.



Josh

 

[John Berger]

For my rig, peak boost went to 30 psi from 28 psi. It doesn't (didn't) stay there, just peaked. Best sustained boost went from 25 to 27 psi. Those numbers are towing and I'm very happy with them. I swiss-cheesed the airbox last weekend and am really looking forward to towing the 5'ver when it gets hot to see if the "increased" air flow helps the EGT's.

 

[RonaldLarson]

I did

and I'm very happy. Put on a Jardine four inch, nice easy install, quieter at road speed, louder at low speed, and WAY better mileage. Mine has increased close to two MPG. I agree, you may not feel a power difference, but it must be there.

Were I you, I would run right out and get some gauging. I have the BD XMonitor for EGT, transmission temp and boost.

Ron

 

[DWest]

Cab noise

ol ron: I just installed a Jardine and like you the install went great, but my cab noise level when pulling is way louder. Did you weld the joints or just go with the clamps? Any of the dreaded drone? DW

 

[stownsend]

I noticed an increase in horse power. I don't have a dyno to prove it, but a person in tune with their baby notices. As you increase the amount of air that goes through that monster, it's bound to increase h. p.



Good luck!

 

[jeeepxj]

Originally posted by joshuajackson

. If I were to do it again, I'd leave the resonator in.







Josh

What exactly does the resonator do ?? I was thinking about removing my Cat. and Resonator a just leaving the stock muffler. In hopes of reducing my EGT's



any thougts ??



craig

 

[Whitmore]

The resinator is there to quiet it down some just like a muffler would do, the only reason I can come up with why DC put it there instead of a longer muffler is because the musta had a ton of these mufflers lying around and wanted to use them up??



The 01 doesnt have a cat just res and muffler



anybody

 

[RustyJC]

Originally posted by stownsend

As you increase the amount of air that goes through that monster, it's bound to increase h. p.

Nope, the only increase in BHP from reduced exhaust back pressure would be due to lower pumping losses on the exhaust stroke. In general terms, the only way to significantly increase BHP is to increase the amount of fuel (BTU - heat energy) you put into the engine. Of course, it then takes more air (intake & exhaust systems, turbos, etc. ) to efficiently burn the added fuel. Just increasing mass airflow in and of itself won't help power, but it will lower EGTs.



Rusty

 

[RonaldLarson]

dwest

Nope, no drone. I sort of expected it from some of the threads I read, but I have no drone. I clamped the joints, no welds. Can't explain the lower noise at speed, but even the bride noticed the difference.

Ron