caveman

I'm interested in how your car will run with the stock air box back on. I think CAI's are a huge scam in the tunner market now days. Reason 1: The notion that you are getting a cold air intake is a joke in it'self because anyone who installes a open cone filter is going to suck in hot air from the engine bay. Reason 2: (this sort of backs up 1 in the DSM tunning world where we have nice loggers n such, people who have cut the air box so the cone filter is open get higher intake temps on the logger. The best way DSMers keep the intake cool once a open cone filter is used is to build a custom air box that blocks hot air from engine. Reason 3: Some MAFs have trouble monitoring/counting air with a CAI setup if there is some sort of bend before the MAF. One of my closest friends who has a old school 5.0 got rid of his CAI because he would have had to pay a lot of money to have a MAF calibrated for the CAI that was on his car. He put the stock air box back on his car and he got a lot more low end and mid range throttle responce and torque.

I don't have the dyno sheet to back this up, but I've read that on a DSM, dynoing a injen intake pipe lost HP compared to the stock intake pipe.

Go ahead guys, flame away, but I say don't wast hundreds of buxs on a CAI system for your car. Just get a in box K&N filter. I don't see how anyone but the engineer of the MAF used would know the effects of a CAI. The stock MAF might acually have trouble with a CAI, but it won't with the stock box. Since there is no real HP gain from a CAI anyway, why not just use a in box high flow filter? A in box high flow filter will flow more air then the stock air filter and you can get more gains with your header. Also, instead of buying a whole cat back exhaust, save money and only replace the stock cat and muffler. I did this on a turbo talon on a budget and I got massive gains. Greated that was with a turbo, installing a larger size exhaust on a NA 2.5 isn't going to give any HP gains, but installing a high flow cat(s), and a higher flowing muffler will. Again, flame away.

The 2.5 engine is not going to produce massive power from the stock HP, and the budget mods are going to work well. You would be better off spending money on tires, suspention, and brakes becuase you can greatly improve them over stock, but the 2.5 engine will never be a power monster unless the whole engine is rebuilt.

Let the flames start. Just keep in mind, I've been in to tunning for some time now and I'm not a expert in this engine, but overall, things don't change that greatly from car to car. I'm really not happy with Nissans current build quality and service, but I can say this, the 2.5 engine in our Spec V (with spec V gearing) probably has one of the best if not the best throttle responce and torque out of any NA 4cyl before. Screwing with CAI's and not knowing the effects of the MAF and installing larger size exhaust's can mess up the torque and throttle reponse. I've seen in happen many times before. Since you can't pull on all cars with the Spec V, you can build it to loose them in the curves and have much later braking. For autox and off road legal racing.

EDIT: I just wanted to add a little on the whole stock air box vrs a CAI. On some cars a CAI will add HP over a stock air box. Some cars from the factory have a extreamly small air box and air filter with very little air getting to the air box in the first place. In a case like this, a CAI would be a better choice because much more air will be able to make it to the throttle plate and intake manifold compared to a factory restrictive air box. The stock air box and stock rubber intake on the Spec V are already large. The stock air box has two intake tubes to grab cool air, the surface area of the stock filter is large, and the stock intake pipe after the air box is large with no restriction. The car already has a good setup from the factory. So it is a case by case thing. I'm not suggesting that good usefull CAI's don't exist, BUT they are way to popular and too many people automaticly assume that the first thing they should do is get a CAI. In some cases, it is more of a bling bling thing and less of a performance adder. In some cases, a CAI can acually hurt HP.