Stage One
Stage One - Quick Access:
Every engine, in its most fundamental description, is a pumping mechanism. For the sake of
simplicity, let's look at the engine as though it were a simple air pump. Air goes in, air comes out. Now, let's say we have a
plastic straw on the inlet to the pump. As expected, we would see the pump working pretty hard to get only a reasonably small
amount of air flow through it; if only because we can see how small the cross-section of the straw is. Now, let's replace the
plastic straw with a garden hose, which is several times larger in diameter. Again, it's natural to expect the garden hose to
flow much more air through the air pump, while not making the pump work nearly as hard as it did with the plastic straw.
This same principle operates in an engine- efficiency and power output are directly related to how well air can get in. How
well the gaseous products of combustion are able to get out, is not our concern in the Stage One section, but will be discussed
in the Stage Two section. At any rate, the need to maximize air flow into the engine, should be obvious by now.
The OEM filter and intake installed by Toyota, does serve the purpose of both cleaning and providing sufficient air for combustion to
occur in the 7M-GTE according to its original design specification. Under these circumstances, it works fine, but our goal here
is to increase power, and efficiency (and in many cases, even gas mileage). So, what's the problem with the OEM intake setup? It's
a low cost solution that is the product of mass production, while taking issues like noise generation into consideration, rather than
maximum throughput of air. As such, it is very restrictive, much like our plastic straw on the air pump analogy. No, we won't be
looking at putting a garden hose on the Supra, but we do need to remove the restrictive stock intake
setup, and replace it with components that will accomplish our goal of increasing air flow to the
engine.
So, now that you want a higher flowing air filter, which do you choose? There are a variety of aftermarket products
available, but for performance, cost AND ready availability, K&N is the way to go. The K&N Fuel Injection
Performance Kit [FIPK] is the most chosen, in the $120 to $140 range. For a budget alternative, HKS still has an Air
Flow Meter [AFM] adapter available separately, normally for their Super-Mega-Flow air filter. Using this adapter, in
conjunction with a K&N universal 3" cone filter, yields comparable results, in the $75 to $85 range. In fact,
if you're ever considering replacing the AFM with a Vein Pressure Convertor [VPC], the K&N universal filter will
fit perfectly onto the VPC's AFM replacement tube.
Cold Air Induction Mod [CAI]
Besides simply improving air flow into your engine, temperature of the intake charge is also an important component in
the equation leading to max power. Basicly- cooler is better.
The CAI mod entails running a flexible hose from the lower grille of your Supra, to the intake opening left behind from
removal of the original, stock air box. This allows cooler ambient air to find a way into the engine compartment, in
proximity to your air filter, somewhat reducing the negative effects of the hot underhood air that normally circulates
there. This mod is documented on the
Supra Web's Tech Tips Page.
Air Filter Heat Shield
The induction charge temp into your air filter can be further reduced by implementing a heat shield. Basicly serving
as a reflector of engine-created heat, the air filter can then ingest much more of the ambient-temp air provided
by the CAI mod, described above. The methods & materials for this mod can vary quite a bit, and you'd be
amazed at the possibilities that Home Depot can offer, but as long as the air filter can be shielded as much as
possible from engine-produced heat, your engine will get more of the cool air that helps you to realize max power.
Ahhh yes, the only part of this tip you were really interested in!
With all due respect to brute horsepower, improving the intake system improves the overall efficiency of
your engine. Thus, while horsepower does go up, a significant side benefit of this improved efficiency is
increased gas mileage! As always, individual results will vary, but reports of anywhere between 2 to
6 miles per gallon are regularly seen.
As any quotes of power increases due to mods are just a best-guess without dyno-testing, keep in mind my
own dyno results found elsewhere on this Site, were all done with tuning in mind, not parts evaluation.
That having been said, I figure with a decent air filter, an effective shield, & the CAI mod, you can
anticipate anywhere from a 6 to 8 rear wheel horsepower [RWHP] improvement on these mods alone; or up to
a 15RWHP increase when combined with mods from Stage Two to Stage Ten.
The variance in both mileage & horsepower figures makes more sense when you realize that no mod really
stands alone; they are intertwined in a very intimate way- usually, but not always, helping each other out
in the process.
My OldShool Supra has been around so long, that it has seen its fair share of various intake system setups. I documented them for the most part & put them on this website- not only to serve as working examples, but also to show that how you go about it, is only limited by your creativity & imagination. See them by going to the Intake System Page.