>>>*The stock factory manifold is simply excellent. I am not sure that for all around use that anybody has ever improved on it with any header.

Now top end? Different thing, yep. LCE, Thorly, Downey, they all do show gains but the truth is that many just move power from one place and put it in another. Add in some torque multiplication gains from RPM and yep. There are gains.

So as with any mod, figure out what you want her to do and get everything working together because for all around everything the factory already did that for us.

For economy it's tough to beat the Hedman piece, and others, they are similar to the stock manifold in the way they run and free things up a bit.. If going aftermarket I would always choose the Tri-Y design over the 4 into one.

Remember that location of the 02 sensor is kinda important too. Plus it needs to be in the flow path, I get emails on tuning probs all the time that trace to a wrong sensor or location.

The big gain? It's in that exhaust pipe and muffler, the factory strangled the little engine to keep it quiet and nice and goosey on the low end for daily driving, also for ground clearence. Not as bad as they did with the 3VZE V-6 but still the exhaust isn't free flowing in stock form, just nicely adequate.

Bigger tires solve the ground clearence prob, so a neat 2" all the way through the cat into the muffler, with 2 1/4" on exit is well proven to be worth nearly 10 ponies to the ground.

Like I mentioned, she still isn't going to be a hot rod but she sure can be more pleasent on the highway....*EB

I'm not going to be doing any desert racing and just don't see the need for an aftermarket header. Plus, that thing can't stay together. The LC stuff never fit worth a damn and none of it lasted... if I could stop anyone from buying from them, I would.

So, I'll put the OEM header on and the downpipe. From there, 2" to the muffler (aftermarket cat/muffler are 2" I think) and 2.25 out of the end is the hot set up? If that's good for close to 10hp, I think that with the headwork and exhaust, it might be like adding another cylinder.

If I can't hot rod my way anywhere, I'll drop a gear and crawl over what ever is in my way. <img src="/forums/images/graemlins/mrt.gif" alt="" />

[color:"blue"] If I can't hot rod my way anywhere, I'll drop a gear and crawl over what ever is in my way.

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......very well put sir......

>>>*The theory on the increase in pipe size at the muffler exit is directional flow. A lot of mufflers are made that way, I have a 2 1/2" into 3" on my big old Chevy truck and she simply sings.

Plus we used to set up our stock cars the same way for racing and found a mile per hour or two on the straights regular as clockwork.

The stock pipe size is a bit too small on the 22RE's, but this can increase low end off idle torque, plus it helps keep things quiet.

Quiet is one of the factory's main goals, they spend as much money on sound as they do on power.

So expect to hear her a bit more with any mods. I happen to be about half deaf so that is a nice advantage....*LOL**...

You hope to head a nice whoosh sound or a steady even purr, then you have it close to right. If you hear popping and banging noises, loud unsteady sound, that is exhaust slipstream fighting itself, and that means you are losing power and economy..

I remember building the exhaust system on my old Nova, it was duals with two pipe size increases on both sides plus a balance tube. I didn't even bother with mufflers, didn't need them....*EB

One more exhaust question... where exactly is the ideal and practical place to start the increase to 2" on the stock exhaust? I'd like to know exactly what to tell the exhaust shop when I go in.

Going to 2.25" after the muffler is pretty self explanitory.

>>>*We normally ran them down the street to a local muffler shop and had them fab it up, they always started right at the existing manifold flange.

I know of several running 2 1/2" all the way, and one Celica with 3" all the way and the folks seem to like them.

Bigger typically means slower gas flow, simple as that. The system likes velocity, so bigger exhaust area would move the power peak up the RPM scale a bit....*EB

There is a good exhaust place just down the street. I'll talk to them about this and see what they can do. Hopefully this will allow me to pass smog. *insert diatribe of cursing and filth directed at CARB here*