Originally Posted by XLR8

From the factory GSL-SE's make 130hp at the flywheel. 150whp is about 170hp at the flywheel. You might be able to hit that number without porting. For that reason you will need the absolute most flow from the intake and exhaust. A downdraft weber will flow abit more then the factory GSL-SE intake setup, but I can understand wanting to keep the mpg and driveability of the EFI. I had an SE a few years ago and performed these mods for the most gain possible. Granted, I didn't have alot of money but the thing ran awesome!!

1. Header with full 2.5" exhaust
2. CAI
3. Pull the entire intake manifold, cleen thoroughly, remove 6 port sleeves and rod actuators
4. Port TB
5. MSD or DFIS of choice.

Do not fret for the 6port removal. I have performed this on 3 GSL-SE car's and have never seen a low-end loss and saw nothing but top-end gains. Fc's may see a loss, but the SE's rotors are the heaviest of any rotary, and that momentum makes the torque consistant down low. It was another "Mazda,......why did you do that?"

Also, Fd's have 4 850cc injectors.

Originally Posted by rotarygod

If you intend to retain the stock factory fuel injection, don't even think about a bridgeport. The stock air flow meter has a total area for air to flow through of 4 square inches. That is equal to a 2.25" intake pipe. WAY too small. You will absolutely choke the engine. To make matters worse, there is a spring loaded door in the way further hindering airflow. It almost flows enough air to supply a single rotor bridgeport! You want to feed 2 rotors through it? No way!

Also just consider the setup you are planning. If you use a 12A intermediate housing, where are the fuel injectors going to go? Also i assume you are trying to use the large port center plate. Look at the size of the intake runners vs. the stock intake manifold. The manifold runners are about half the size. Don't even think about port matching them. You will lose a ton of air velocity once the air gets to the center housing. This will slow down the intake air and less will actually get in the engine. The center ports are also the wrong ones to bridge if you are only going to bridge 2 of them. You have far too little airflow through the intake manifold for a bridgeport. Actually this is true for any ports. The stock intake system is a huge restriction.

Your combo is a prime example of how bigger is NOT always better. Your proposed setup may actually be even slower than stock! Yes it is possible. What counts in the power department is the total package. It all has to work together properly.

I have a GSL-SE. It is streetported. I ported it myself so I am very familiar with how it was done. The end housing ports are about the same size if not very slightly larger than the stock 2nd gen intake ports. The primaries are a little larger but nothing insane. One very common mistake you see damn near everyone do on this forum is to go hog wild with the porting on the outer housings. Don't ever open both ports up into one large one. You'll kill velocity and make no low end power. Since your stock afm is so restrictive you won't make much about 7000 rpm anyways. Do you want a motor with no low end or top end? My ports are very close to the ones on Mazdatrix's site.

Here are the mods on my SE up to this point. Cone filter. Didn't notice ****. Long primary collected exhaust system. Very nice power upgrade across the whole rpm range. It's the first thing you should do. Underdrive pulleys. Maybe felt something but not enough to really matter. Light aluminum flywheel. Oh yeah this is noticable! MSD direct fire conversion. This is a very nice upgrade as well. It makes the car run really smooth. Starts are better and gas mileage is improved. It sounds like a 2nd gen now. Reset timing to 25 degrees total advance witha 10 degree timing split. Combined with the direct fire conversion, this was noticable. Streetport. Yes the car is faster. All of the other mods up to this point have made a much larger improvement than the porting did though. Is it worthwhile? Yes. Do it last! I have an S5 n/a intake manifold. The 6 port system and the VDI still work. While the afm is still a restriction, the VDI effect on the car improves the top end. The next upgrade for me is a standalone ecu. This should make the biggest difference yet and it isn't uncommon to see 15% gain in power just solely off of the fact that the airflow meter is gone! Then you can also tune it to your combo. All of these things work together very well.

If I were to bridgeport it, I would go no faster. I would be forced to change intake manifolds and ecu's. I would lose drivability and gas mileage. I would not pass inspection. Without a port job, you can get an SE to run mid 14's!

Do everything else first. Trust me on this one. You'll be glad you did. Then save porting for last and even then don't go too crazy. This forum is full of people who insist bigger is better but you never see anyone with a street driven car with bigger dyno numbers than the streetport guys. I wonder why! My car idles at a stock 750, makes good low end power and still gets me 20 mpg in the city. Good enough for me. If I wanted more, I'd turbo it. Why sacrifice drivability for speed when you can have both?