panic wrote:I'm looking for a cold air kit for my G2 3.3, but all the leads I track down described as "cold air" are simply aftermarket open sided filters at the end of a curved extension.
Is there a product out there?
Some of what is claimed and posted about intakes is complete rubbish. In general, there are a few things that may help:
1. new tube has larger radii and/or diameter than original plumbing - improves air volume
2. the tube (and the entire tract) must have a smooth interior wall - the flexible, conformable flex tubes are completely worth - the spiral or corrugated inner wall drastically reduces air-flow
3. new filter area is larger than the OEM - but not always an accurate comparo since not all filters flow the same per square inch of area.
4. a filter re-located to anywhere inside the engine compartment gets only pre-heated air from the engine. Under WOT the heat throw-off from the exhaust and hot air pulled through the radiator by the fan is huge.
5. pointing an external intake scoop forward does not produce enough "free supercharging" to make much difference, the wind pressure is only about 1.2% at 100 mph
6. even a K&N has to be big enough to work; example: a 3.3 peaking at 6,000 RPM needs about 47 square inches of filter to work (6" × 8" panel, etc.).
Formula: engine size in liters * RPM ÷ 418
3.3 × 6,000 = 19,800, ÷ 418 = 47.4 square inches
7. when you remove the original stuff, you get a bit more intake roar (sounds nice, though!), but I'm not sure if it cancels any Helmholtz benefits? Is the stock air box a resonator?
8. the biggest power boost you can get from changing the intake duct is cold air - the difference between 70° ambient from the exterior vs. 150° or more inside the bay is large. The duct from the entry need not be continuous diameter - it can end in a big box containing the filter, then another tube back to the TB.
What I'm looking for is an intake that has a remote tube ending outside the engine bay in front of the bodywork (grill, under bumper, etc.). The better ones will have a water trap to prevent rain and road dirt from reaching the filter.
Thanks for any leads or links.
Please bear with me...I had previously looked for a lot of info on this subject.
I believe the Toyota Air Filter assembly provides an "adequate" filtered air supply but more so to quiet down the engine: RESTRICTIVE. Sometime ago, I was performing DeepCreep cleaning alongside with complete air assembly and left out the elephant trunk looking inlet on reassembly (stock box with filter in-place)... I quickly put it back; the engine not only had deep low growl but also introduced vibrations...didn't like it!
Numbered replies:
(1&2). The
CPE air intake system is one of the best solutions for the 3.3, even though its an SRI...it has larger diameter intake tube and works AFR (set or tuneable). I don't know about CPE CAI extentions yet, but like PXL said its difficult to do (even for somebody with the 2.4L engine like tacti). CAI might also have faster flow velocity since the air is disturbed earlier in air induction stage than with an stock or extended SRI.
Cheap CAI:
(3) K&N oiled cotton flows better than paper for the same size; they have demo on some auto part stores.
(4) Many people confuse CAI Cold Air Intake and SRI Short Ram Intake (and some take advantage of that). Still, having an extended SRI taking hot air from under hood (but further away from heat sources) cancels some of the benefits of higher air flow but to a lesser degree than a simple SRI. Still, higher HP on any SRI over stock might come from shortening of the air intake tract which usually gives more HP sometimes at the expense of torque. Still, for some people the pros top the cons.
(5) The 1.2% might not seem that significant, but having a scoop (nozzle) raises flow velocity. Less pumping losses?
(6) I'm lost (please explain what is the purpose of formula). Still, I think this follows what you are saying:
Massive RX8 filter
(7) Helmholtz... finally the answer for the open window and/or sunroof buffeting (vibration) felt inside cabin. I believe that is the only purpose for those multiple resonators (I think my car has 3).
(8 ) Completely true...alas, in real life and hot weather, it might not make much of a difference.
One of the cleanest air intake designs I have seen is the RX8
REVi. Bigger K&N round filter with "horn" towards MAF, inside a closed box for cooler air intake. There is also a
RamAirDuct.
In the RX8 case, they can make a cold air extension and put the filter directly in front of radiator:
![Image](http://www.turborx8.ca/pictures/cai3.jpg)
.
Scoop anybody?
K&N (others too), sell a sock type cover for filters that prevent excessive dirt and water from going into the filter:
Don't mean to threadjack, but after pondering on the options I wish I could have a stock 3.3L airbox (additional air intake ducts over the 2.4L and bigger entry)...maybe even modify it to allow one of the air ducts to act as air scoop (ram air). It might be the closest to the REVi system. Maybe you could make a ram-air add-on that dumps directly onto the stock scoop (dedicate 1/2 the scoop
Big 3.3L engine bay pic). This way, most the dirt and water would fall into a white canister our engines have below the battery.
In the end, it all comes down to the limits of your imagination and how much $$$ you can dish out.
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