I have an h23a w/ an AEM CAI. I am adding an AEM Pulley and DC CC Headers soon. I am also adding a cutout valve to allow me to bypass the cat and muffler. I will be pushing the maximum high end power from the exhaust using the bypass valve, but it has poor power until you hit 3500rpm.

Anyway my question is what is the best exhaust combinitation to get maximum low end power (thru 3500rpm) when i use the cutout, and decent mid-high end power for when I dont use the cutout for the money? I also dont want much sound from the muffler since the intake/header already makes lots of sound.

My options are:
1) Stock Piping, Universal performance muffler.
2) Stock Muffler, Custom Piping (what size is good?).
3) custom piping and muffler.
4) stock muffler, stock piping.

 

Here ya go and don't bother with the cutout.

I just read an SCC article for the month of November on this very subject.

The worst thing you can do is keep the stock muffler....that is the major problem.
If you budjet is decent then I would go with the custom everything. That would be 2.5" exhaust. Don't go any bigger unless you have a turbo or nos planned in the future. Mandrel bent piping and strait-through resonator and muffler. SCC got all of these things from Magnaflow. When you get the strait through muffler and resonator make sure the piping is perferated not louvered. In other words just holes not little aerodynamic groove thingys...they are anything but aerodynamic. The bigger the muffler and the longer the muffler the better....same with the resonator, if they are true strait-through, they aren't going to hurt performance they are just going to be quiter.....the quieter you are the less of a target you are form the Cops. You can also get a performance Cat.....again from magnaflow. I have the article sitting right next to me if you have anymore questions or I forgot the answer anything just post again....I should be looking.

 

But why would this be better than using a cutout at higher rpms?

 

why would you want power under 3500?

 

well, a little low end power is nice for daily commutes... it's nice to have a little get-up-and-go torque...

 

The engine is N/A it will loose power if you give it a strait dump off the header.

 

I am n/a and the concept as the after 3500 rpm i will be able to gain the most hp by bypassing the muffler and cat. The thing is taht until 3500 rpm I will need to buildup backpressure for torque, so when the bypass is closed I will be able to get good low end gains.

 

you need SOME backpressure to make power against. If the easiest way to make power was to just dump the exhaust.. there would be NO aftermarket exhaust,,, market. Everyone would just be dumping the exhaust straight out of the Exhaust manifold.. into the engine bay.. lol

 

Okay, I am going to tell you to read the SCC article. One, I don't want to rewrite the whole thing. It is in the Novermber 2001 mag and it is under the wrenchreport "Build your own Exhaust" That will answer everything. Since you really want this to be good quality I sugest just waiting until you can read the article. Trust me.

 

Go to a automobile autostore and get a cutoff(y-pipe) with the cable...the cable is installed in the driver compartment and u just have to pull that cable to open and close the cutoff...u should just enlarge your piping to 2.25 or 2.5 and keep the stock exhaust if you want the sleeper look...just pull the cable after 3500rpm so you dont lose the lowend power and once the cutoff is open you will gain the highend...I am assuming that u are only using the cutoff for the track because if you plan to use it in the streets...COPS WILL HEAR U LIKE 3 BLOCKS AWAY...

 

I know. I was asking how I can optimize my performance for the time before i use the cutout (below 3500rpm) and for the times I dont want to use the cutout (on the street).