Thread: gotta go bigger then 2 1/4 inch exhaust?

Thanks for the update. I'll have to recommend the one designed for the smaller displacements from now on for the N/A VE people. Turbos I think the "bigger" one is still a smart move. Even our weakest turbos easily flow more air than those 4.0L Jeep engines.

Cool thanks for the updates guys, ill place an order with advance on Friday.

Do you guys think I should use a resonator also, or just the muffler should be fine?

To save money and weight, go without a resonator.

Do you have a catalytic converter still? If not, you might want a resonator to mellow out the sound when the muffler valve is open. It's kind of up to you. The exhaust should be pretty quiet with just the muffler (as long as the valve is closed). You can always add a resonator later.

If you have an NX, I have a 3" complete exhaust that has been sitting here in my garage for like 3 years. It's not stainless, but its fine. I was holding on to it when I had my turbo nx with intentions to use it but had a side exit made.

If you are looking for performance but want to maintain a quiet sound... I would suggest building your own for cheap and adding a muffler to the rear section:
http://www.sr20-forum.com/naturally-aspirated-all-motor/132-how-build-quiet-inexpensive-3-side-exit-exhaust.html

I have this for sale if you would want to pick it up as well.


If interested I'm located in Cincinnati, Ohio

Thanks but I'm probably gonna go with a small regular resonator. This is my DD and im trying to save money to finish my other projects.

However, a good friend of mine says that a 3" exhaust is pretty damn loud on a VE. Oh wait...that was you that said it. ......


When is a 3" exhaust really necessary? When does one actually lose power with a VE due to the exhaust being the limiting factor on air-flow through the engine?

Are the people doing a 2.3 or 2.4 liter motor going bigger than 3"? If not, are they restricting their big-block builds due to exhaust flow? If they are NOT restricting their big-blocks with a 3" exhaust, then the 3" exhaust must be larger than is required for a 2.0 liter VE with basic bolt-ons (I/H/E, tuning).

At what point will a 2.5" (mandrel bent) exhaust actually restrict the power output on a stock block VE due to airflow? Is a 2.5" exhaust a restriction on a "bolted-on" and "N1 cammed" VE? How about just a bolted-on VE, stock cams?

I have an SSAC header, 2.5" mandrel-bent piping, stock cat (2.5" in and out), Magnaflow straight-through resonator (2.5" in/out), Vibrant straight-through muffler (2.5" in/out). At what "build" point in "VE-land" will that exhaust actually restrict my power output?


Bingo.


See my questions above. When, exactly, is a 3" exhaust necessary to avoid losing power due to a restrictive 2.5" (or smaller) exhaust?

IIRC, Miko figures that kind of shit out with some fancy math on air volume in and out, etc....

The exhaust is always a restriction Shawn. It's a matter of what kind of a restriction you want to live with, and the point of diminishing returns. The diminishing returns parts is going to depend on each individual's needs. It's not like there is a leveling off in efficiency on the graph where you can mark it and say "here, that's where you can stop going bigger with the exhaust". So it's going to be up to each person how restrictive of an exhaust they can live with in the attempt to keep noise down.

I like very large exhausts. I recommend free-flowing stuff. You however would be happier with something less loud (and less powerful). So for you, a 2.5" on a VE or even a built VE might be just dandy. For someone else looking for every bit of power from a VE, a 3" exhaust might be the minimum.

Are the big displacement guys leaving power on the table with a 3" exhaust? Of course. How much? Likely very little. If you want hard numbers, that might have to happen later or from someone else.

The exhaust is not always a restriction. It depends on the header being used.

Want to see a stock VE make 130hp? Put a 2 1/4 exhaust on it.

Let me rephrase.

Everything after the last collector, merge or associated size transition is what I'm calling the "exhaust". And that is always a restriction.