I'm thinking about putting a dual exhaust system on my extended cab 4x4 2500 6 lug '95. I would eliminate the soot trap and go with two flowmasters, mandrel bent. How would this compare to a single 4' exhaust? Would it be able to handle future mods such as 80 hp injectors, and chip?

Duals?

You can't have true duals as you have a turbo. All the exhuast runs through the turbo before going into the exhaust system. The least back pressure after the turbo the better. How you do it is your call really.

As far as the "80 hp injectors" the injectors do not control how much fuel is put into the cylinders. That's the IP's job. The "any gained HP injectors" do not work like they are advertised. The injectors alone will not give you any more fuel. Don't waste your money. Just buy a good quality(Bosch is OEM) OEM set injector and you'll be fine. I have OEM set injectors in my truck and still gained plenty of power with the Heath Reflash.

The exhaust outlet on the turbo is only about 2 1/4" in diameter.

Anything over 3" would not be restriction.

So duals would be just extra weight to haul around. 4" would be overkill.

DieselPro, is that for all the GM-x turbos?

More or less.

There wasn't much change between them all, just simple things to improve flow, softer bends, nothing as drastic as the turbo changes on the Duramax (LB7 had the IHI RHG6, and everything else has had a Garrett VGT turbo)

They all have the same sizes and specs as far as the wheels and housings go for the GM-X series.

The major difference was the exhaust elbow on the GM-8, the wastegate was housed inside the elbow, rather then in the actual turbine housing like with the earlier GM turbos used on the 6.5.

Also the wastegate actuator was a vertical opperation on the 8 vs horizontal on the earlier ones.

Hmm ever since I got this thing I've been thinking the manifolds and turbo are huge restrictions. Has anybody ever tried building a FULL custom exhaust? Everybody and their dog (including me and mine) slap a straight pipe on after the turbo, but has anyone built custom headers with a bigger turbo?

Hmm ever since I got this thing I've been thinking the manifolds and turbo are huge restrictions. Has anybody ever tried building a FULL custom exhaust? Everybody and their dog (including me and mine) slap a straight pipe on after the turbo, but has anyone built custom headers with a bigger turbo?

I know of two people. Both running twins.

One is running and uses twins (can't remember the turbos). (Bill Heath)

One is not running yet and uses two GM8 turbos (at the moment). (Chevyinlinesix)

IAMDAVE & DIESEL PRO nailed it !! Maybe Steaksauce has some "real" 80HP injectors,LOL. No dual muffler system can be as effecient as a single pipe3 or 4 in.system. Especially since the single system is lighter,easier to install & will cost less in the long run.

Turbo outlet is closer to 2-1/2 inches...... I goofed on the 2-1/4"

Turbo outlet is closer to 2-1/2 inches...... I goofed on the 2-1/4"


So basically a 3inch system will yield the same restriction as a 4inch system? So save the cash and just got 3inch all the way back?

yea man there is no reason to have duals, except for looks,which duals don't really go with diesels dosen't sound the same either, especially flowmaster mufflers, don't get those they suck, they sounded good on my old dodge gasser, until they rusted within a year and i don't live near salt water or didn't have hardly any contact with any, just rusted then also the welds came undone inside the muffler, made a lot of bad noises until i got a magnaflow system, get a good flow through muffler or just don't put one on at all.

If you want duals just buy a set of stacks like GreenMachine is running on his teeruk. Otherwise just run a 4" system buy whomever you choose to purchase from. Its plenty,you gain an average of 1.5 mpg's most of the time. With the exception of the first few tanks because your going to be a Lead Foot (trust me you will). It also lowers EGT temps and back pressure great bonuses for hauling any sizable loads.

especially flowmaster mufflers, don't get those they suck, they sounded good on my old dodge gasser, until they rusted within a year and i don't live near salt water or didn't have hardly any contact with any, just rusted then also the welds came undone inside the muffler

Thats weird, I had a flowmaster on my old S-10 and it was fine. I live a mile from the beach near San Diego.

steelraptor: I got a crossover, downpipe and straight exhaust for about 300 shipped to my doorstep. Ebay search for a warpspeed crossover and a diamond eye exhaust. It only took about 2 hours for the whole thing. Get a drill with a uni-bit or some other sturdy bit to hog out the flanges for the crossover. Mine weren't drilled right and once I opened up the hole it was fine. Have fun listening to the turbo and your truck since it can actually breathe now.

Ryan

So a single 3" will perform as well as a 4" on the 6.5? Has anyone done back to back testing to confirm this?

So a single 3" will perform as well as a 4" on the 6.5? Has anyone done back to back testing to confirm this?

Considering the largest downpipe available is 3" unless you make your own the 4" system is just a step up from a 3" downpipe.

At first i took the factory system, including factory crossover and downpipe, and made my own straight pipe system, and the truck could breathe just fine. That's proof to me. Factory system is only 2.75, and at the end of my system i just shoved some 3" pipe over the remains of the factory system.