New to the form just bought a 2002 2500 long bed 4*4 ctd and I want to step up the power a little. Well everything I have been reading on the forms said start with a exhaust and air filter well here's were I don't know were to start on which exhaust they are so many brands out there I will be using my truck as a everyday driver and pulling my fifth wheel in the summer to the coast 400 miles round trip. I have been reading about the dreaded exhaust drone that drives people crazy well I don't want that if it can be avoided. So what's the best bang for your hard earned money that you can hear yourself talk in the cab.

 

The Drone isn't bad, but if you have any plans at all to up grade go with a full 4"-5" exhaust kit. You can also buy an after market intake but if you want to do it cheap NAPA sells af's that will fit directly into the intake tube and all you have to do is pull out the stock af and box really easy and works really well.

 

if you want to step up the power a little, dont waste your money on an exhaust and intake. a 65hp module would be just fine with the stock breathing.

BUT, invest in some gauges first! dont let your VP44 (injection pump) starve itself of fuel. and be able to keep an eye on your EGTs.

 

^Yes, get some gauges first. The exhaust doesn't really give any benefit, just sound. Get the cheapest one you can find. They're all about the same. I got mine from MarkoIdaho on ebay and am very pleased with it. Great fitment and quality. Get a muffler though because straight pipe gets annoying to listen to on the long trips.

 

I would go for the gauges first. But I don't agree with the rest.

If you plan on keeping the truck, Spend an extra $57 and get a stainless steel system with a lifetime guarantee and a free tip.
http://cgi.ebay.com/ebaymotors/ws/eB...MEWA:IT&ih=020

To go the cheap way out and then replace it again in 5 years doesn't make sence.

It's also hard to argue with the performance numbers of the 4" systems

12-18 HORSE POWER

~30 FT./LBS OF TORQUE

UP TO 250 DEGEES LOWER EXHAUST TEMPS.

1-2 MPG INCREASED FUEL ECONOMY

 

Lower egt's is about all you're going to gain from an exhaust on a stock'ish truck. Fuel economy maybe 1 mpg, if that. I've heard people say aluminized is better than stainless.

 

I'm wondering... Is the stock exhaust stainless, aluminized or what??
My 96 is currently in perfect condition. I just want something bigger that will breath more.
Also I noticed on the magna-flow site that the 4" SS system for 98-02 has a 3.5" down pipe. Does anyone know if any of the other systems out there does this or do they have a true 4" down pipe?

 

Stock is aluminized, as are almost all OEM systems-- it's the best combination of low cost and enough corrosion resistance to keep the OEMs meeting emissions requirements.

4" is nice to have, but the money spent on a box like XZT+ will be a far better investment.

JMO

 

So unless your in a corrosive climate/environment going with stainless would be somewhat superficial??

 

Honostly, if I were to do it again I'd go with a 3.5" downpipe. It fits better between the engine and frame and supposedly has better spool up than a 4". It's all you need.

 

Hmmm I always thought more was better for spoolup EGTs and such.
Why would 3.5 spoolup faster? Not doubting you just wondering why.

 

Stock was stainless on 1994-01 trucks. Not sure if they changed on 02, but I doubt it. Most high end vehicles have been using stainless stock for over a decade. If you live in a dry state like AZ or NV get aluminized, otherwise get a stainless, it's worth the investment. There's nothing more annoying than replacing sections that rot out every year. Remember too diesel exhaust creates sulfuric acid and is more corrosive than gasoline engine exhaust. I live in the salt belt and plow snow- my truck has seen work from the day it was delivered and I have the stock stainless exhaust minus the muffler (which rusted through after 7 years- common on the 1995-1997) and the hanger clamps.

The smaller (stock 3.5") down pipe creates more back pressure causing the turbo to spool up faster the the lower back pressure the 4 inch down will generate. If you're planning on doing any reasonable mods in the future get the 4" down- once you start fueling up the 3.5" down's back pressure will raise EGT's.

A 5" is too little back pressure for anything less than majorly bombing a truck- stay away from it unless you plan on releasing at least 800ft-lbs and even then a 4 inch will handle it. Webcruzer- the spool issue on your's may be the 5 inch exhaust more than the 3.5 down pipe.

Check out Banks - notice what exhaust systems they make? no 5 inchers....4 throughout (some 3.5's) and that supports their 1000 ft-lbs twin ram setup with good EGT's and spool up with their quick turbo.

If you have a cat equipped model the first thing is gauge then #2 is a hi-po cat or drop it all together. That is more backpressure then you would believe, especially if you have let it idle for any length of time over it's life.

 

Stainless factory exhaust? Really? I'm surprised, but them I'm not, too-- if that makes sense. The EPA requires oems to build an exhaust that lasts 10yrs or something like that before the vehicle is EPA certified as legal for sale.

I'll confess that I always thought my oem system was aluminized, and I just assumed without checking-- so thanks for catching that.

With the lower grade 409SS, it's sometimes hard to tell just by looking as both the 409 and the aluminized will get that "tan" corrosion on the outside a bit.

IMO, 5" is justifiable but only on a truck with compound turbos. A regular single turbo just can't move enough air to justify a 5" over a 4".

Bank$ doesn't deal in compound turbos.

 

Hmm, Im not sure about this statement. A turbo is a very simple idea-air flowing over some vains causes a rotation in a shaft. the faster the air moves & the higher the differential pressure across those vains will cause more energy to be transmitted.
Lets exadderate it a bit-if there was 0 (zero) differential in pressure across the turbo, there would be absolutly zero flow. If the exhaust side of the turbo is a lower pressure than the engine side, then you being to have flow from the higher pressurized engine manifold to the lower pressure atmosphere.

So, the greatest differential in pressure possible will aid in moving more air faster-causing the turbo to spool up faster.
I cannot see how having any back pressure will aid in the spooing of a turbo. Please correct me if I am wrong, but I just cannot see it.

 

i would say the misconception about a bigger exhaust reducing power/torque/spool-up is saying its due to greater backpressure. it has to deal with flow, not pressure.

when the exhaust exits a 3" turbo outlet and runs into a 5" downpipe the exhaust flow hits a 'ridge' where the 3" jumps to 5" and creates turbulence and disrupts the flow. add a ridge in any type of flow stream and you'll have losses...

i think a downpipe should be conical in that it slowly grows in diameter along its length.