Porting a 1ZZ-FE Exhaust Header.

[ilovecorollale]

This time i did search and read through carefully....it is said to gain 9 hp and torque by porting ur exhaust header...so i want to ask if anyone else besides the people on that thread, has done this to gain hp and seems difficult and not so really difficult, since i am such a newbie on this forum.

[Downhillzze110]

i know porting the intake manifold and bypassing the throttle body heater line will net you a few HP. i could see how porting the exhaust header could be a poor man's substitute for headers. but you'll also want to port match the head. might want a machine shop to do THAT though

[fishexpo101]

Depends on the vehicle in question. On the 1ZZ-FE engined vehicles, the Celicas respond very well to porting. About a 9HP figure is what I've heard floating around. Though with the Corolla its ECM is not as flexible nor as forgiving as the Celica, has a different tune, valves themselves are slight smaller, and differences in how the induction system is setup.

Porting is part "art" and part "science". In the reach of a DIYer - possibly, but you'd need to invest some money into tools and parts. Sourcing test manifold to practice with, and have access to a flow bench to verify your work. Some shops offer porting services that run from $150+, you ship them the manifold. No guarantee that you'll hit nice power gains. But couple that ported header with intake and catback - might see close to 9HP gain on the Corolla. Even with the ported Celicas, some saw gains as little as 3-5HP, so like they say - your mileage may vary.

Most have reported better throttle response with porting, a few reported more seat-of the pants speed and acceleration. But again, with "butt-dynos", YMMV. But if you are really set on doing this, go for it. You won't run into fitment issues or CELs that plague aftermarket header options. Plus the overall cost out of pocket is generally less than other options.

If you run a piggyback or standalone EMS, you might be able to squeeze out a few more ponies. Best option is to run a race header (4-1) with stepped primaries to keep the velocity up, otherwise run a 4-2-1 to minimize losses to low end power. Keep in mind, even under the best cases, with an intake, header, exhaust, and tuning - might only see 10-15WHP gain. Doesn't sound like much, but when the car is only putting down 100WHP or so, a 10-15% gain is HUGE. Could also drop 100-150 lbs of excess weight and unsprung mass from the car and get the same overall net performance gain.