4" vs. 3" exhaust system

[bigfig]

I have been wanting to open up my exhaust for more power. A lot of companies are selling 4" exhaust systems and others just selling 3" replacement pipe for the muffler. I was wondering if anyone has put in a 4" exhaust system and was there a large increase in power, or is it a total waste of money and should I just stick with a 3" exhaust and just put a straight pipe where the muffler is? Appreciate any advice.

 

[JKloppe]

No it will not be a big increase in power but it will lower egt's and spool up will be faster.

MORE FUEL = MORE POWER
MORE AIR FLOW AFTER TURBO = LOWER EGT

Jordan

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·1999 2500 QC LB Auto 3. 55 4x4
·Armorthane Bed liner, A-pillar gauges, RE-0880, EZ, 275's, Husky mats, strait pipe

 

[EMDDIESEL]

A stock exhaust with a straight pipe will never flow as much as a 4" exhaust. Even if the 4" has a high flow muffler it will still outflow a straight 3". The faster the exhaust can get away from your turbo, the faster it will spool and therfore the faster your engine will accelerate. It will also keep your EGT down.

 

[MHindman]

I have the stock 3 inch system with the strait pipe in it. It sounds pretty good, but with the tst pm3 my egt's go up to about 1300 pretty quick. It doesnt go much farther than that, but keep in mind that all im doing is driving it hard, no trailer. I am going to the 4 inch system real soon. Just to let the Cummins breath. Then i will be able to go to my big injectors. . and really run!

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(Silver Bullet)1999 Ext Cab 4X4 5SPD, All options. Power Max 3(adjustable), K&N Filter, no muffler, Pyro,Fender Flares, Toolbox, bedrail covers, 450 watt Kenwood Sub, 33 12. 50 16. 5's, 3. 54's... Soon to have: 4inch, DDIII's, Southbend clutch.

 

[bigfig]

Say, anyone happen to know who has the best prices on 4" exhaust systems? (I assume stainless is the best)

 

[EMDDIESEL]

Jardine i think i read was the cheapest. I have a Jannetty kit that was about $540. 00.
And no, Stainless steel is not the best. It will last the longest, but aside from that, there is absolutley NO advantage to stainless, it is strictly appearence issue.
Aluminsed steel (which is what most of the kits are made of) will last at least 5 years, probably longer. I have seen aluminised kits on gassers in the Northeast last 8years or more. It will just get a little surface rust after a few years, thats all.

If you are not going to keep your truck for much longer then that, you really cant justify almost DOUBLING the price to get stainless. You can almost buy 2 Jardine kits for the price of one Banks stainless kit. Just get a nice stainless tip, that really all you can see of the exhaust anyhow.

I dont care if the exhaust pipes under the truck that you can only see when the truck is on a lift still look "Pretty". The difference in price from stainless to aluminised will be much better spent on gauges, a deep trans pan, a Psychotty, etc.
Honestly, Banks is overpriced to begin with and there customer service is HORRIBLE. I wont even install there stuff on customers trucks

 

[PHuckleberry]

What about a cat-back? (resonator-back?) My trucks exhaust is 4" out of the res, wouldn't a good 4" in/out muff. and tailpipe do the trick? Thanks!

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My truck 01. 5 2500 4x4 SB,quadcab,auto,3. 54LSD,tow/camper pkg,HD241,bronze; Dad's truck,96,3500,ext cab,4x4,5speed,4. 10LSD,white