Rick F.

So what's the verdict on replacing a 4th gen 4.0L V6 stock air intake with an aftermarket CAI? I've been looking at the K&N and the TRD and would lean towards the K&N with my current lack-of-knowledge.

Also, my current experience with the CAI on my Mustang is that you get a bigger bang-for-the-buck by getting a new tune (equivalent to a chip reflash). Anything like that for our 4th gens?

Geez, when I alternate between driving my '00 3rd gen with the deckplate mod and then the '08 4th gen, I feel the '00 has a lot more pickup. Help me out here, guyz.

dave2one5

I'm trying to figure out the same issue with my '02 3.4 supercharged engine. Is it better to just do the ISR mod or buy a cold air intake system? Also, I've heard conflicting views on whether or not the deck plate mod is a good or bad idea with the Supercharger?

Rick F.

I think you'd get an answer sooner in the 3rd gen section. I still have my 3rd gen and did the deckplate mod but not the ISR, although I'm not SC'd. But I'd have to think (there I go again) that doing both and allowing more air in would be a GOOD thing...

dave2one5

hahaha, woops, forgot to check where the thread was when i searched...that is what i would think, , but is the stock 3rd gen fuel system going to be able to keep up??

Rick F.

Hope you're not asking me... My 3rd gen is staying NA. Most likely so will the 4th gen. All that sort of $$ goes into my Mustang.

Rick F.

Bump...

C'mon, guys. I can't believe nobody has some input.

William

Not necessarily.

If there is still somewhere else in the intake/exhaust that flows less than the area where you do the modifications, or if the engine can't pump enough air in the first place to be able to make use of the modifications, then there will be no gain.

Lets say you install an aftermarket cold air intake that has the ability to flow up to 600 CFM (cubic feet per minute), and there is another part of the intake that has the ability to flow up to 550 CFM (such as the throttle body, for instance), maximum flow can never exceed 550 CFM.

The only exceptions to that would be if you added forced induction. (supercharger or turbocharger). Or if you modified the entire intake, the heads/valves, and the exhaust for more flow throughout the whole engine. Or increased displacement. But for the sake of this discussion, we will focus on an otherwise factory stock, naturally aspirated engine.

Lets say you do just happen to replace the most restrictive part of the intake with a freer flowing aftermarket part. But what about the heads? What about the exhaust? If they also don't allow at least as much flow as the aftermarket intake part, then there is still no gain.

Lets say that by some miracle you end up replacing the part that indeed IS the most restrictive part. What part of the RPM range would be the most likely to receive all or most of the power/torque gains? The most likely answer would be at or near red line, when the throttle is wide open, which is when the engine is pumping the most air.

How often do you run the engine at or near red line (most likely, not very often)? And if this is true, the how effective would the modification be in real world situations? In reality, not very effective.

I've used K&N products before and have NEVER seen a power increase. In fact, when I went to do a tune up on my Tacoma (which I bought with 15,000 miles), I bought a Purolator replacement air filter, only to realize that the previous owner had already installed a K&N air filter.

I replaced the K&N filter with the Purolator filter and noticed absolutely no loss of power.

Then later on, I decided to experiment further by doing the much recommended secondary air filter removal modification. Despite several people insisting that this modification made an increase in power, again, I felt no difference.

In fact, some claimed that there was also a fuel economy increase. I have yet to see it, despite measuring mileage for several tanks of gas. That does make sense, because if more air is being sucked in, then the fuel injection system will compensate by also adding more fuel.

So you may end up spending money only to find out that you wasted your money.

With all of that having been said, IF I were to buy an aftermarket intake, it would be the TRD brand. Why? Because it is designed and approved by Toyota. The engineers that designed the truck know more about how to get more power out of it than the K&N engineers do. So that would be your best bet.

However, you STILL may find out that you wasted your money...

Rick F.

I fully understand the issues with the limiting factor(s) that may be involved here.

The deck plate mod (basically a 4" hole upstream of the filter in the airbox) had a definate seat-of-the-pants performance increase in my 3rd gen. I'm assuming that the intake on the 4th gen is restrictive to some extent in that a CAI would do something positive.

Advertised claims (yeah, I know) of roughly 10-18 HP are possible whcih means to me 5-9 if I'm lucky and that may be at the crank and not the rear wheels. Even so, a 5RWHP gain is seat-of-the-pants noticeable in my opinion. I'll continue to research but I WILL be buying something soon. Just was curious what the concensus was.