For those who don't want to bother with a 626 manifold can do something like this. This is what I do with them.
http://www.mazdaspeedtuning.com/manifold.jpg
http://www.mazdaspeedtuning.com/manifold2.jpg
This creates more air flow, leaner afrs, more midrange to peak power pull. I'll have a dyno graph shortly once i retune the guys car. For a stock untuned car, the afr will still be rich just not as pig rich as it was. A tune will extract more power.
Pros - everything fits properly, you retain vacuum ports, no CEL, sleeper modification, frees up a vacuum port for running an independent source to the bov and wga.
Cons - sleeper modification, labor to hog it all out takes a while
No cold start up issues. You must leave the 2 VTCS/VICS solenoids plugged in, but remove the actuators and all the vacuum lines to the solenoids. You must also remove the green/white check valve in middle of the manifold and put a straight piece of vacuum line there, be sure you use high grade silicone line and reuse the clamps, replace all the gaskets for a leak free seal and torque to specs.
You are increasing the volume of the manifold by hogging out the entire VICS chamber. Deleting the VICS flaps alone doesn't do anything b/c it is just an empty chamber with no air flowing into it. It's just a stagnant air chamber. Instead of a chamber of air opening at 5200 RPM, hogging out the manifold you have a large volume of air all the time.
The VTCS is a emissions system to increase turbulence to improve start up emissions. Other cars have similar systems. VTCS is more of a restriction compared to the VICS.
There was a Miata in Dsport that had a similar modification done on the BP 1.8 and it gained around 25-30 hp from doing this modification, the builder dyno verified it. Car made about 500 hp to the wheels. I spoke to the builder of that Miata and he says its a worthwhile modification alternative to a sheet metal manifold. We were going to offer the service for modification, but it was too labor intensive even on a lathe to offer it to the public. The cast aluminum is difficult to grind down. The amount of the labor would have been around $500 to complete the modification.
It'll work on NA cars, but I have only put it on turbo proteges. The gains from doing this will be more beneficial to turbo cars. I would get a spare manifold somewhere and try this so you can compare the 2 if you are trying do this on an NA protege.
http://www.mazdaspeedtuning.com/manifold.jpg
http://www.mazdaspeedtuning.com/manifold2.jpg
This creates more air flow, leaner afrs, more midrange to peak power pull. I'll have a dyno graph shortly once i retune the guys car. For a stock untuned car, the afr will still be rich just not as pig rich as it was. A tune will extract more power.
Pros - everything fits properly, you retain vacuum ports, no CEL, sleeper modification, frees up a vacuum port for running an independent source to the bov and wga.
Cons - sleeper modification, labor to hog it all out takes a while
No cold start up issues. You must leave the 2 VTCS/VICS solenoids plugged in, but remove the actuators and all the vacuum lines to the solenoids. You must also remove the green/white check valve in middle of the manifold and put a straight piece of vacuum line there, be sure you use high grade silicone line and reuse the clamps, replace all the gaskets for a leak free seal and torque to specs.
You are increasing the volume of the manifold by hogging out the entire VICS chamber. Deleting the VICS flaps alone doesn't do anything b/c it is just an empty chamber with no air flowing into it. It's just a stagnant air chamber. Instead of a chamber of air opening at 5200 RPM, hogging out the manifold you have a large volume of air all the time.
The VTCS is a emissions system to increase turbulence to improve start up emissions. Other cars have similar systems. VTCS is more of a restriction compared to the VICS.
There was a Miata in Dsport that had a similar modification done on the BP 1.8 and it gained around 25-30 hp from doing this modification, the builder dyno verified it. Car made about 500 hp to the wheels. I spoke to the builder of that Miata and he says its a worthwhile modification alternative to a sheet metal manifold. We were going to offer the service for modification, but it was too labor intensive even on a lathe to offer it to the public. The cast aluminum is difficult to grind down. The amount of the labor would have been around $500 to complete the modification.
It'll work on NA cars, but I have only put it on turbo proteges. The gains from doing this will be more beneficial to turbo cars. I would get a spare manifold somewhere and try this so you can compare the 2 if you are trying do this on an NA protege.
Last edited:
