I run LT headers, no cats and no mufflers. I feel I am missing some low end torque with this setup...or maybe Im just used to it. Has anyone here gone from a similiar setup to a setup with mufflers and noticed a difference? -Thanks

 

have you gotten the car tuned?

if not, thats why you lost the power

 

Yes its been dyno tuned.

 

You're running LT headers with NO cats and NO mufflers - did I read that right?? That must be LOUD and stink like hell (raw fuel). It's also the reason why you don't have sufficient back pressure. The tune won't do much to remedy that. I thought California required cats to pass emissions, etc. Anyway, if you can run without cats - find a good set of mufflers and it should definitely improve your situation by providing some needed back pressure.

 

you dont need backpressure, you need scavenging
if you use too large of an exhaust you lose that scavenging effect


do you have a before/after dyno chart?

 

hey man ive started another thread asking this exact question and no one will answer me....anyway..are you running a straight pipe off your x pipe? no mufflers? you think you aren't making very good power? I would think that setup has 0 restriction which would = best power.

 

The "scavaging effect" is a function of the headers and x-pipe, not the mufflers. Back pressure is a function of the mufflers, which is what the engine also needs to perform optimally. It sounds like the OP already has an O/R x-pipe, but no mufflers. 0 restriction does not always equal better performance. The x-pipe promotes improved scavenging effects by smoothing out uneven exhaust pulses from the engines firing order.

 

0 backpressure does not equal maximum power. at least not avg maximum power across the entire range.. like how its measured in an engine masters challenge for example.

pulse tuning/reversion does have something to do with it as someone mentioned.

 

Sounds like you need a venturi in your collectors. No real science to what size. Need to tune for this on the dyno. Very common in short track race engines.

Here's some info on the idea...

http://www.carcraft.com/techarticles...tem/index.html

 

You took the words right out of my mouth! A PROPERLY designed exhaust system places all the key components in the optimum areas. When you cobble a system together or significantly change the one designed for your car, its a hit or miss scenario. I bet ya if you data logged your car ON THE ROAD, you would see lean or rich areas in your WOT Air /Fuel ratio.

The HOT exhaust gasses are NOT a solid flow of gas. Instead there PULSES that exit the cylinder and flow more like a fluid than gas. The size of the header pipe , collector placement, X or H pipe placement Mid Pipe diameter and length all effect how those pulses react with each other. They can either help the next pulse exit or fight against it. The term is cylinder scavenging and if set up properly it actually PULLS the exhaust gas out of the cylinder.

 

The optimal amount of backpressure is 0.

 

OK, thanks guys. So what would you suggest for my setup?

 

There are TONS of C5 engineered exhaust systems to choose from. Trust me on this one. Slapping on a $2500 ct back exhaust system isn't going to get you in the mid 11's.

A good CAT back system should be purchased for three reasons:

Sound Quality (personal taste)
Future mods
Quality

NOT for the HP aspect. Yes,,,you will get some HP/TQ improvement but, like I said, not a whole lot. If your goal is massive bolt on later down the line, 3" system may be something to consider. You can expect about 10-12 HP depending on what your tune does.

Having CATS only cost you 3-4 HP on a stock or near stock vehicle so,,,,Its in your benefit to either get High Flow cats OR reuse your OEM Cats. The raw fuel smell will drive you nuts and emissions people wont like your car when it comes time for inspection.

I strongly recommend that you find an exhaust/muffler system on another C5 that you think you want and ask for a ride in the car under varying driving conditions. If you select a system that has excessive DRONE, you will sell it quickly. Make sure that you find a car that has the same tranny and engine mods that you have or plan on adding. It does make a difference.

Heres my Stainless Works complete system on my 02 ZO6 From the collectors back its a true 3" system.







Here the headers on my wife C6 ARH style system





Stainless works is very good quality header, fits excellent and works excellent.

BC

 

http://www.superchevy.com/technical/...exh/index.html

 

Thanks for the suggestions. I ended up putting Magnaflow stock replacement mufflers on. The low end torque is back and its as quiet as a Caddilac now, wich is actually a nice change from the constant drone.

 

 

Go Z06 ti's with cutouts and get the best of both worlds, I had the same set-up you did and went with ti's with DMH cutouts. Its awesome.