exhaust upgrade question
 

I have a 99 dodge 2500 24v with just a k&n airfilter and 3" straight pipe exhaust with the silencer cone outta the turbo, I was wondering if I go up to a 4 or 5 inch straigt pipe do I need to do any other mods to make it work properly without damaging anything

no damage will result by replacing the exhaust.

+1. I picked up about 1.5 to 2 mpg going from stock (non straight piped) to 4" exhaust. Minimal change in power, slight decrease in spool up time (slightly more responsive turbo).

5" is for BIG fueling mods or throatier sound. I don't think you pick up much economy, and no real performance gains over 4" unless you are fueling over 400hp.

The exhaust will pay for itself in a HURRY. Don't hesitate. I guestimated my stainless exhaust to break even on fuel savings in 30,000 miles.

And you don't need any "upgrade." Just order an exhaust set-up and you're set.

so would a 4" or 5" exhaust be better cause thats what i want is that throatier sound

i also dont wanna have any current or future damage done to the truck or engine since its basically stock, my next question dous anyone know where i can get a kit for sorta cheap since im kinda on on a budget with a wife truck and 4 horses to pay for

You won't see any gains going to 5", and may actually diminish performance. I went from 3.5" to 4" on my '03's and didn't gain anything. I also went from a 4" tailpipe to a 5" tailpipe, that netted some "throat".

Remember that a diesel has drive pressures against the exhaust valves unlike a gasser, so exhaust tuning is not so responsive.

Also, I'd save some coin by skipping the stainless, my OE tailpipe lasted over 500,000 miles before it rotted.

THIS guy is very reasonable, makes some nice stuff and is a pleasure to deal with.

EDIT______
AFAIK, you won't pay for an exhaust system with fuel savings. I have almost a million miles on 3 Dodges using different exhaust systems, programmers and injectors ........ gaining 2mpg from anything is largely a myth, or wishful thinking.

JHardwick what was that guy it didnt post, also how hard is it to make i go out in front of the rear tire or can i get a kit to do that? is there any diferance in throat or anything

That's a link, click it.

I've always made my downpipes and bought the tailpipes. The run from the turbo to the muffler is pretty straight. Use some 45's and cut slivers (sections) out of them with a 12" chopsaw and weld everything up.

i got my exhaust on ebay for 180 bucks. 4 inch turbo back. it is way ezer then makeing your own and takes like 20 minutes to put on.

how does ur sound and perform and is it stainless or aluminum? does it have a nice deep throat sound to it

i love the way it sounds. has a deep sound. when i am towing and it gets worked it get really loud. it is aluminum and i dont have a muffler.

get a 4 icnh downpipe from mbrp, diamond eye, etc. they all make good ones. mine is mbrp and its aluminized. takes 10 min to put it on. then go to summit racing and buy a couple 4 foot lengths of 4 inch diam pipe. pretty cheap. me and my buddy did this to his 02 short bed then his dad had a common rail that he had taken the stock exhaust off of so we used the part the goes over the axle and the tailpipe cuz its all 4 inch to. looked pretty good and sounds good. although other than my 4 inch downpipe, its all 5 inch

EDIT______
AFAIK, you won't pay for an exhaust system with fuel savings. I have almost a million miles on 3 Dodges using different exhaust systems, programmers and injectors ........ gaining 2mpg from anything is largely a myth, or wishful thinking.[/QUOTE]

My gains were from hand calculations tank to tank. Not from myth or wishful thinking. These were the numbers I got. Some tanks I saw about 1.5 mpg gain, some 2mpg gain with the only mod being the exhaust before and after.

After adding injectors, I gained even more.

On stock tires and stock exhaust/injectors I got 14 usually, and 16mpg tops. I put on 35's and mpg didn't seem to suffer much, but my best on a tank after exhaust went to 18mpg. After injectors, I occasionally hit 20 or 20.5, but usually got about 19. Hand calculated corrected for speedo inaccuracy.

I only counted "best" on a tank to help offset other variables like towing, driving style etc. IE the "best" I could do stock was 16mpg. After 4" exhaust the "best" I could do between fillups was 18 (though 17.5 was more common).

Maybe not everyone will see this, but I did. Not a guess, not an assumption, carefully collected numbers results posted up on Cummins forum.

When you go to a larger dia. pipe, some have trouble with the fit around the spare tire.

Floyd