First post
Don't know too much about mods.

Is installing a CAI kit a waste of money without changing the whole manifold?
I know the CAI won't raise power much, if any, but I've been wanting to start doing low-cost mods on my car just to start learning.

 

On our cars a drop in filter with the air silencer removed works just as good, unless you also want the look. Then I would just get a ebay CAI with a quality filter.

 

The best bang for buck mod as far as power, is usually a re-gear+tuner setup, this will require you to pay someone to install though. But a good suspension/brake upgrade can make a car loads more fun to drive as well.

 

+1

As stated remove the silencer (snorkel) on the intake and put in a K&N filter, same thing as CAI for a fraction of the price. Very little gains either way.

 

These cars already have a "Cold Air Induction" kit on them from the factory, and much like the similar thing on a Porsche 924S/944, it's not as restrictive as some would make it out to be.

The OEM system draws cold air from outside of the engine compartment, just like the aftermarket systems do.

It draws through a tapered snorkel with a radius flared, horn-like end, that silences airflow largely due, in simple terms, to smoothing and accelerating the airflow to keep air molecules from colliding in to each other as they enter the system. It doesn't "choke airflow" like armchair engineers think it does and if anything, it increases it at the expense of muting cool "sucking in the ionosphere" sound.

In the OEM system, the air goes in to an air box with a conical shaped, high-flow air filter that has more surface area than many aftermarket filters do. That OEM filter doesn't require oil to provide filtration, so there's no risk of over-oiling, which can cause residue build-up on the delicate Mass Airflow Sensor and cause it to not meter correctly.

Most aftermarket systems go to the trouble to draw in cold air, only to move it through a heat-retaining metal tube. How much sense does that really make? The only way I would consider an aftermarket intake on a naturally aspirated split port 3.8 is if the tubing were made from phenolic non heat-absorbing, non heat-retaining material.

The short of it as that while they look cool and sound bitchin', aftermarket CAI's in general do not provide a beneficial airflow increase to these 3.8L engines and can, at least in theory, wind up making less power than the stock OEM system does.

An aftermarket CAI isn't something I'd spend my money on.

 

Concur.

When you remember that the engine is nothing more than an air pump, you realize that the engineers want the flow of air through the engine to be as efficient as possible. This improves fuel mileage, so the car companies actually pay attention to it. They will spend a million dollars to get a car's EPA rating to the next "magic number" (from 19 to 20, 24 to 25, 29 mpg to 30 and so on), because not only does it help them sell that particular model of car, but what they've done will also translate to other models they make.

In earlier days, intakes were more or less at the "suitable" level. There was a lot of room for improvement, and you saw lots of different attempts to do so. Drag racers in the '50s and '60s would take T-shirts, dip them in motor oil, let the excess drain, then tie them in place of the top cover of the factory air cleaner -- the K&N air filters are a direct descendant of this. Guys racing on the dry lakebeds bought surplus fuel injection systems from the Air Force and figured out how to make them work on cars (despite predictions from the automotive "experts" that they could never be practical), and today Aunt Tilly is driving around behind TBI.

What really made the difference was computer modeling. Chasing the perfect trade-off between fuel economy and performance, computer-designed intakes have improved airflow to the point where only incremental improvement is possible, and even those changes are things like smoothing the inside of the intake manifold.

Given the above, there really isn't a lot to do to a street car which isn't just for show. If you're racing, sure, you want every last itty-bitty improvement, but on the street the speed limit is the same for a super car as it is for the family sedan.

 

It helps to have a vision of what you want the finished car to be and a plan on how to get there that has mods build on each other while eliminating duplication of work where possible.

Coming from a road-racing / autocross background, the general order I like to follow in modding a car is: Tires and / or Wheels; Chassis Stiffening; Suspension; Brakes; Rear Axle; Driveshaft; Transmission; and, finally; Engine and Exhaust.

I can only use the power that the tires let me put on the ground and good tires offer a performance and safety benefit at any speed, whether on the road, or on the track. I do chassis stiffening next, or at least decide if I'm going to do any and if so, how much, and what form it will take, because this will influence my suspension set-up. I tend to do suspension before addressing brakes because suspension impacts braking performance due to the effect it has on weight transfer. The rear axle is next, but at this stage, I already have a general idea of how much power I need. I'll have a transmission overhauled / built to handle the expected power level and power band of the engine before I do anything to the engine itself. Engine and exhaust are dead last on my list of priorities, generally. Tires, chassis stiffening, suspension, and so on are all mods that can be enjoyed on the street or on the track, at any speed.

Your plan might be a lot different than mine. That's okay. The important thing is to have one, because it mitigates both frustration and expense.