So I have a set of Megan Headers and a OE-RS exhaust. Trying to decide if the horse power gains are worth the rasp..What do you think?

 

They are not worth any rasp... I run MR header with precisionmuffler exhaust and don't get any rasp... The gains aren't huge, but rasp just annoys the heck out of you if you have it.

 

What exactly causes the "rasp"?

 

Higher exhaust flow, which equals more vibration, too much for most mufflers to handle, so it provides the famous rasp.

....to my knowledge.

 

Not fully understanding why there's a rasp? Perhaps I need to hear this rasp...

A muffler just causes sound to basically cancel itself out right? So is the sound passing through the muffler so quickly that it can't fully cancel itself out?

 

Mine usually occurs between the 2.5k and 4.5k rpm range, regardless of how hard i am accelerating. I was under the impression that the rasp came from the lack of a cat. converter in the aftermarket headers...which is basicly adding straight piping blah blah blah

 

I am the sole "no" vote as of right now.

The downsides of a header-

1) Exhaust sound volume goes WAY up. Even the quietest exhaust on the market, the PM axleback, becomes pretty buzzy and high-pitched. Driving on the interstate becomes a hassle, because the slightest engine effort becomes a loud affair.

2) It is illegal. Removing a working cat is VERY bad news for anyone who gets caught. You're booted out of STS in autocross, must uninstall every year for an inspection sticker, and hope that you don't get pulled over for a quick inspection by the po-po.

3) Raspy as hell when cold.

4) Warranties become an issue. S/C becomes no longer warrantied, and toyota's likely to blame miscellaneous crap on the fact that there's additional heat in the engine bay.

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I had the megan racing header on my car for about a year... I grew to be embarassed to drive my car on the roads... picking up non-car friends was no longer cool, and the girls hated it.

Now that I've removed it, I love my car again.

 

What? You have to remove the catalytic converter to install new headers? I don't get it...I'm obviously a noob...

 

The stock exhaust manifold has a cat built into it. Replacing the manifold removes that cat.

 

The OEM manifold has a pre-cat.

 

I see...I always thought the cat was somewhere between the various exhaust piping not in the header. Is the tC different in this regard?

 

Seeing how the tC has a "pre-cat" then that means there's another after it. In keeping with tradition, a cat will be somewhere along the exhaust, in the tC's case, its on the mid-pipe, like most cars.

 

I've never heard of a pre-cat...does it basically clean up the exhaust a little more? That makes sense I suppose...


Thanks for all the replies guys

 

I ended selling my header two weeks after installed . Didn't like the rasp

 

Actually guys the cat on the manifold is the main cat. You can always tell which one is the main cat becasue it has the 02 sensor on the front of it and the rear of it. The cat underneath the tC is the secondary cat. The main cat burns emissions and the secondary cleans up whats left over. When you remove the main cat, there is more flow.

Scionlife member Zebman explained it perfectly on here:

When adding a header you basicly release the power of the motor, and to quiet it down. I highly recomend our axle back. it keeps the rasp down and still gives you the flow needed for optimum performance.

 

you can always buy a 30 inch resonator and get it put on the mid pipe to replace your old one. that's what i did and the rasp is gone

 

wih the stock muffler?

 

no i have the HKS axleback

 

Wait a second. Adding headers makes your car illegal, or is that just in Cali?
I'm not toally clear on NY State Laws, but I thought You only had to have 1 Cat on your car (which would be the one on your midpipe.)

2, Is there any companies that sell midpipes with 30" resinators and Full Cats installed / welded, and ready to go? the ZPI and MR are just straight pipes

 

See with our axle back you don't have to worry about adding a resinator. :D No cutting or welding required. I am sure the HKS looks good too, though. No hate on them at all.