Originally Posted by wsoape281

this is a frequently asked question post about modifying your protege. these topics have been covered enough times here to require a post to outline them. i will cover the naturally aspirated and forced induction options here and go into the options of internal modifications (pistons, rods, oil systems, ect.). this will be divided into bolt-on, top-end, and bottom-end.

first things first, you need to choose whether you are going naturally aspirated or forced induction. in all honesty, naturally aspirated is way more expensive power for power, but much more unique. you can argue that a turbo kit is expensive, but with most cars, you can double the wheel horse power with just 7-10 psi and the right supporting mods. with natural aspiration, it would easily cost you the value of the car to come anywhere near that and odds are that you would never even reach double the wheel horsepower.

i have covered natural aspiration in great depth with info from a member from another forum, thread titled "N/A theory" ( https://www.mazdaforum.com/m_71331/tm.htm ) but i will go over the basics with you here. forced induction will be covered to it's full extent here. i will go into turbo selection briefly since all of the bolt-ons are basically the same after that.

TURBO KITS

your turbo selection depends on your power goals and uses for your car. a larger turbo is going to lag more, but put down more power. a smaller turbo is going to lag less, but run out of steam in high rpm's. the mazdaspeed protege uses a gt25, so that is usually a good place to start. a gt25 will spool quickly, but won't put down a ridiculous amount of power. remember, the harder you push a small turbo, the more problems you will have with it. a common upgrade for these is a gt28, which will support the motor over 220 whp. some people have tried gt30's and gt35's, but these are very large for this motor and there are not definite whp numbers. i, personally, have seen 1 car that has put down 400 whp with a gt35. that is a really ambitious goal and will cost a lot of money and tuning to do, but is possible. you also need to remember that the higher you get into hp, the less street driving abilities you will have.

BOLT-ONS;

intake, header, exhaust

these will be your biggest bolt-on gains whether you are forced induction or naturally aspirated.

for natural aspiration, you will want to get an exhaust that will reduce the back-pressure, but not too much. the exhaust needs a certain amount of restriction to operate since it uses exhaust pulses to pull more exhaust out of the engine, therein reducing the amount of energy the engine uses to expel exhaust. the N/A theory post goes further into naturally aspirated exhaust selection. with turbo, the hot-side holds all of the back-pressure that you will need, so you can use the same size exhaust that is coming off of the outlet (i.e., some turbos have a 3" outlet, you can continue that through the entire exhaust). i will go further into turbo exhaust mods later.

header selection is pretty much the same for either turbo or n/a. you want a header that will open up the exhaust and have equal length runners. this concept is covered in the n/a post, but i will go ahead and cover the basics of it. basically, what you are looking at doing is allowing the motor to exhale more easily and causing exhaust pulses to reach the collector at the same time that another pulse is expelled so that one spent exhaust pulse pulls the next one out at a certain power band. the longer the runners, the higher in the band that you will produce power. 4-1 is the best exhaust arrangement for this effect, but n/a also has 4-2-1 which will open the exhaust further out, but will not do what i described above.

intake selection is pretty cut-and-dry. there are two basic kinds of intakes; short ram and cool air. the selection is widely open to speculation and there are many facts, opinions, and exceptions. the main thing that you need to consider is that air has mass and pressure. like any other thing which has mass, it travels best in a straight line and in one direction. the more curves that an intake has, the more restricted the air flow will be, bottom line. a short ram pulls air from the engine compartment, which a lot of people say will reduce the horsepower. it does, however, use shorter tubing which allows less flow restriction. a cold air intake will pull air from outside of the compartment, but will be much longer intake tubing and require more bends to pull from outside of the compartment. my opinion is that a cold air intake is going to have too many bends and has to go through the engine compartment anyways, which will cause the air to heat up. it also tends to cause turbulent air to hit the MAF which can cause inaccurate readings. remember, this is only an opinion and even though i am a mod here, i am still entitled to it.

that is all for i/h/e. this is all open to speculation, but there it is take it or leave it.

ignition

this is kind of open to speculation whether or not these are bolt-ons, but my feeling is that you don't have to crack open the engine to get to it, it is a bolt-on. the basic elements of the ignition system are the spark plugs, coil packs/distributor, and plug wires.

spark plugs are the cheapest and easiest mod that you can do. there are a lot of different plugs to choose from and all of them make all kinds of claims. remember that they are all just advertising. no one in their right mind is going to push their product as inferior, so just keep that in mind. the only tests that i have seen on spark plugs have brought platinum 4 point plugs and e2 plugs to the top of the charts. these are all about minimizing the electrical resistance and making a quality spark. i am willing to bet that you will never notice a whole lot of difference between plugs, but the dyno will see some. don't be afraid to spend 30-40 on plugs if you feel like you need to compare. you will at least get it back in gas later.

there is a coil pack mod that you can do which is simple and frees up a few extra hp (if you have a 2.0l, that is). the 1.8L coil packs are different than the 2.0 and seem to add a couple of hp numbers to the 2.0. the steps that you have to go through are a little extensive, but pretty cheap (comparable to other mods you may do). you need a 1.8L valve cover, the coil packs, and the plug wires. all of them are direct fits, but you will have to find a place to mount the coils. most people mount them on the front of the valve cover. there are other coil pack mods, but they require custom plug wires and boots, so i recommend having a fabricator do that work. you can use pretty much whatever coils that you want, you just have to have wires made for them.

wires are pretty key here also. you just need to find a set of wires that will keep the resistance down. there isn't really a whole lot to say here, so that is about it.

i will be back with more posts, but that is all for now.