4" vs 5" exhaust?

[LightmanE300]

God my checking account hates me. I have my 2004 HO on order and am already thinking of accessories. Which is better, a 4 or 5" exhaust? Likely I won't modify it too much, but could eventually do light mods like mild injectors or a box of some sort. . towing of relatively lighter loads, 5-7k lbs. Mostly unloaded though. Thanks

 

[WadePatton]

Mr. JD has stated many times that a 4" will support around 500-550HP. So 5" isn't necessary for most of us, but we like it anyway.

 

[nickleinonen]

Originally posted by WadePatton

Mr. JD has stated many times that a 4" will support around 500-550HP. So 5" isn't necessary for most of us, but we like it anyway.

watching/listening to the clips on the DD website i think the 5" sounds better. 5" pipe has a little more deaper mellow tone i think [due to the lower velocity of the exhaust flowing through it maybe?]

 

[LightmanE300]

i wonder if the lack of restriction/backpressure on the 5" will take away performance from the stock engine?

 

[PGoble]

i have the DD 5" Exhaust on my '03. I love it except when cruising down the highway at 75 mph. It has a drone that it much more noticable than the stock system. After talking with DD, they say it is quieter than the 4" system.

Peter

 

[LightmanE300]

Great info PGoble. Not sure if I'd like the drone, since I'll be doing a lot of highway travel.



Has anyone actually noticed a gain from just adding an exhaust system to an 03+ HO? Or an intake for that matter? Aftermarket manufacturers and retailers of both intakes and exhaust always make ridiculous claims.

 

[WadePatton]

OHMIGOD don't start.

With the drone thing again. I've been trying to 'splain it to the 3G folks for a few days now.



If you have drone it can be FIXED. Change something. Move the muffler or add a muffler or change the muffler or clamp iron to the system. Just do something and it will change if not go away entirely.



My setup has no drone at all. I did have drone with the muffler cut out of the factory system. I also had drone with the straight 5". I may have drone when I try a 5" resonator. But right now with a gutted 10x51 donaldson on a BE 5" I have none at all.

 

[J. Steve]

4" vs 5"

Will a 315 spare fit with both systems? It seems like I read somewhere that it'll fit with a 4" but not with a 5" exhaust but I can't find that post again.



I'm asking for my brother who just picked up a '03 2500 last month. Thanks guys

 

[WadePatton]

The 5" is tight with my 265 spare, but then I'm not driving a 3G.

 

[sheffield442]

DOES ANYONE KNOW WHO HAS 5" EXHAUST THAT FLARES OUT TO 5" RIGHT AT THE TURBO OR DO THEY ALL US 4" DOWN PIPE AND THEN FLARE OUT???? BIG EXUAUST. COM USES 4" DOWN PIPE.

 

[J. Steve]

Originally posted by WadePatton

The 5" is tight with my 265 spare, but then I'm not driving a 3G.

Maybe you (or anyone) could answer a question about my '02 for me then (sorry wrong area, but on the topic). I'm running the 5" Big Exhaust (strait) and it's against the shock and the spare, unless I let the tire down, move the spare far to the left, then bring it back up while holding it over. This also only lasts a week here on Tucson's nice roads before it bounces back over. Anyway, I guess my question is if you have a similar problem on the 2g or 3g? I fear damage to the spare, or even a fire, but for more than a month now, there's been neither problem. I don't know to leave it, or do something else to fix it. I've been considering heat wrap around the exhaust, but unless I can get an inch of space to stay between it and the tire, I don't imagine it would help.

Thanks in advance, Mike

 

[WadePatton]

BE 5"

I had to cut mine twice. I left it a bit long the first time and had it up against the spare. Look long and hard at it and see if a few inches off the middle section will move it away from the spare.

 

[4xquadrod]

5" on a 03

I have a 5" exhaust and it does not have a clearance problem with the spare tire.



I also strapped on some iron after reading this thread yesterday and it helped at certain rpms. Tomorrow I plan on trying to eliminate all of it. Thanks WPatton





Steve

 

[krabman]

I mounted both and took measurments with an spl meter. The 5" is louder both to the ear and to the meter at idle and all the way on up. It does have a lower tone that may be preferable to some. Use 2 dampners (muffler/resonator) and you can be pretty sure you will not have any drone at any RPM. Mounting an exhuast made no change whatsoever in terms of hp on the dyno in my case but it did lower egts. I am running a 4" muff with resonater setup and it is actually a little quieter at idle and cruise (as measured with spl meter) but has a very nice little bark when flogged. Kind of like having your cake and eating it too IMO. In this case I wouldnt worry about power, you will not be gaining or losing any as long as you stick with straight through muffs and resonaters. The volume and tone quality are what you are buying so your ears and tastes should be your guide.

 

[ROCKJEEP]

4xquadrod did you add weight to the stright pipe to help change the resoniss of the pipe. If so did it help.

Kory