cold air intake

[Amack76]

i really want a cold air intake, but can't find one, i've heard the general concensus is buy one for a different car and cut it. someone please submit more info on the topic, and how much hp increase is projected.

[paultvx]

In general, 5 HP at best for cone filter on naturally aspirated motors (any motor)... in cold weather. In hot weather, your performance may actually suffer... most noticeably the first couple seconds from a standing start. Heat soak. If you must use a cone filter, make a heat shield that, in effect, creates an air box around the filter to minimize heat soak.

An internal combustion motor is basically a constant displacement air pump. It can only pump/draw in as much air as it can displace. A cone filter and a different intake pipe may ease some intake restriction to help the motor breath easier. But, look at the stock airbox and intake tube... pretty obvious it doesn't need much improvement. The intake path is fairly straight with only two bends. One at the TB and one at the elbow. Use of an intake kit would be pretty much be for cosmetic reasons only. No huge benefit in performance gain. If it ain't broke, leave it alone.

Once you add a supercharger, it's a whole new game.

[MrCrowley]

Although removing the restrictive elbow in the fender and using a K&N filter is about the best you can do. Less restrictive AND cold air. A year ago I wanted to start a snorkel, and after seeing the Thailand rally post, I am thinking about it again. The easiest way may be buying and modifying a Trooper snorkel. Who knows...

[paultvx]

Removing the elbow will not get you cold air. At a stand still, the engine will be pulling in hot air from the engine bay rather than the fender. Once the VX gets moving, you'll still be pulling in hot air until air rushing through the engine bay from below and through the radiator (hot) lowers the engine bay temp some... which is still higher than ambient air temp.

Don't believe me? Buy yourself a $20 digital thermometer from Radio Shack with two remote temp sensors and a sensor built right into the display unit. Put one probe inside the enigne bay, put the other in the fender and tape up the opening with duct tape (to isolate that air space from that of the engine bay). The built-in sensor will read ambient temp. Take it for a drive on a hot day and have a passenger record temp readings at half mile intervals... and take note of the particular driving condition each readings were taken (i.e. highway cruising, city driving, stop and go traffic, etc.). After the drive, take the data into MS Excel and plot a temp vs distance chart of the three readings, you'll see how one reading correlate to the others. Once you've got your proof, return the thermometer to RS and get your $20 back.

Trust me, the stock intake system is pretty damn efficient. The only reasons I would do a intake with cone filter would be:

1. for looks
2. to free up space for other goodies by removing the air box
3. if I had a supercharger

Even then, I would not consider doing it without a good fitting heat shield. We don't have a "H" badge on our grilles... stay away from snake oil mods.

[Jolly Roger VX'er]

Originally posted by paultvx

Once you add a supercharger, it's a whole new game.

I was just wondering if you could elaborate more on this...Are you meaning in conjunction with Aftermarket Air Intake? Really interested in what you've had to say so far and very interested in hearing more!

As far as a normally aspirated VX, I am thinking that the only way to truly enhance performance over the stock airbox (unless 5 hp
and good looks are all you care about!) would be to resort to some type of "ram air" or "cowl induction" via scoops or ducting in order to feed the "cool stuff" into the intake. Achieving this
without hacking or butchering up the hood or other panels would be the key.

Many years ago I did some mods on a 1982 Trans Am which was a dog with the stk. 305 Crossfire injection(dual TBI) . In short
this was what I did:

1) Replaced stk Air Cleaner with dual Chrome open-faced air cleaners giving a "dual carb" look and increasing air flow into intake. Opened up Cowl induction hood scoop by removing butterfly so that it remained open and helped vent heat too.
2) Changed thermostat from 195 deg. to 160 deg. to richen up fuel mixture in accordance with more air flow from #1.
3) Installed "real" dual exhausts and eliminated Catalytic Converter (really illegal now days..lol.) exiting turbo mufflers.
4) Installed Accel High Energy ingnition coil, Accel Perf. distributor cap&rotor, 8.8mm racing wires, Splitfire plugs.
5)Replaced Mechanical fan with Electric Fan.
6)Crane CompuCam
7)B&M Mega Shifter

* When I was done the car went from a dog to frying the rear tires on dry pavement! My Ultimate pleasure came when I drag raced a ZR1 Corvette (4 cam 32 valve V8) and beat him in the quarter mile!

[Joe_Black]

The best way to lower underhood temps is to take advantage of the existing aerodynamics of the VX rather than modifying for at best poor performance. The rear section of the hood produces a significant low-pressure area which would be well suited to an extraction-type vent. This provides a way to move an increased amount of air through the engine bay which would translate to decreased temps. This increase in airflow would also benefit intake flow as well, although marginally. Providing shielding against radiant heat on the airbox and ducting coupled with the airflow increase should net some consistent gains. As mentioned in earlier posts, you simply won't get anything significant until you go to forced induction.

When N1 was working on the CF hood insert there was to be a prototype with an Evo-style extraction vent. Since he became ill it may be some time before that happens if at all. In the meantime I've been working on a way to incorporate that mod in an existing insert and will share the info once tested.

[paultvx]

With forced induction, it's a different game because more performance can be gained with intake mods. Typically, a turbocharged motor can see 20-30 HP gain on the dyno with just a cone filter and no other mods. With a charger (turbo or supercharger) the motor is actively seeking more air compared to a NA motor which takes only as much as it displaces. This is why it is crucial to have free flowing intake and exhaust in a FI car in order to maximize the benefits of supercharging.

Think of the motor as an air pump... it's a lot easier to understand and visualize that way. Better yet... simplify and think of it as a single piston/cylinder motor... a basic model super soaker type water gun... or a syringe. Let's say it's a 10 ml syringe. When you pull the plunger/piston back to draw water... if you pull it back at to the 5 ml mark, it'll only draw 5 ml of water. And, if you pull it back all the way to 10 ml, it'll only draw 10 ml of water. What if you want to draw 15 ml? and you only have that one 10 ml syringe? The only way to get more water into that 10 ml chamber is to compress the fluid. So assume you attach the syringe to a pump to force the 10 ml syringe to hold 15 ml of water. With the additional 5 ml of water, the syringe's chamber will become pressurized and the force of the compressed water molecules pushing against one another will force the plunger back... if you don't hold the plunger in place with force, the plunger will be pushed out of the syringe and spill 15 ml of water on to your table or floor (which displaces 15 ml of air). Same thing with a motor... when intake boost is increased... at some point you will have to use stronger forged connecting rods, head studs, and other hardware to keep the motor from blowing apart.

To make more power, you need more air. When you have more air, you have to supply more fuel. When you have more air and fuel, you have to have a hotter spark or you'll get a inefficient combustion and waste gas and not make as much power as you should. Everything is related... it's rare to mod one thing without having to mod something else too. There is no such thing as a cheap bolt-on big power mod. Some people might say you can bolt on some cams and make more power. Well, not really. Cams don't make more power. They just move the power band around along the RPM range. High end, low end, or mid range. If a company claims to make more power all around with their cams... they're lying. Keeping the motor NA, the only way to get more power is to:

1. Stroke and/or bore to get more displacement
2. Increase compression ratio with different pistons
3. Less restrictive exhaust (small gain)
4. Less restrictive intake (small gain)
5. Mess with ignition spark and timing (small gain)

Internal motor work is retty expensive stuff. Supercharging costs about the same (stage 1), if not less... and makes more, if not the same, amount of power. Less labor involved too.

A ram-air type intake could work... but only in accomplishing the task of supplying/surrounding the filter with ambient (or near ambient) temp air. You won't see positive intake pressure from a ram-air intake until you reach speeds of 100 mph or so... a speed our 130 hp (at the wheels) 4,000 pound truck won't see often enough to take advantage of the ram-air effect. Cowl induction, on the other hand, is a much better way to lower engine bay temp and to encourage air flow from outside the engine bay to within. Those body hugging hood scoops you see on a lot of the import body kits (and some OEM muscle car hoods) are for cosmetic purposes only. For hood scoops to function, they have to sit at least 1" to 2" above the body surface. The classic Pontiac GTO, for example, air hits the leading edge/face of the hood and skips right over the scoops. This is why the pro drag funny cars have scoops sitting way high above the hood. It is also the same reason why F1 cars have the intake scoop above the driver's head... just about the highest part of the car.

Ron (vxconcepts.com) is working on a carbon hood insert with a extraction type vent.

[deton8r]

To get a little more back on topic...

I'm also interested in an intake tube for my s/c Axiom. There's a s/c Proton VX with a cool carbon fiber intake tube that was borrowed from a different application but was unable to figure out what that was. All I was told is that you can't get the carbon fiber one anymore.

Does anybody know what vehicle that was originally for or what looks like it may work?

TIA

[paultvx]

I'd make one if I had the $ for mold making materials.

[paultvx]

I'd make one if I had the $ for mold making materials.

[Joe_Black]

Intake tubes have to be shielded or insulated to work effectively at delivering cooler air. Believe me, with my Merkur/Sierra experience I've been down this road. If you can keep the radiant and ambient engine bay temps away from your induction components you'll only benefit. It usually isn't very pretty though, with aluminized wraps and metal or ceramic shields all over the place. But you can't go fast and look good under the hood! Well, to the knowledgeable it would look good, but not to the ricer crowd.;pg;

[BlackVX]

Sunday I decided to remove my Injen air intake and put back the original part.
The reason is that my "Check engine" light came on and off for the past 2 months. The code is related the O2 sensors and I have to take the VX to the dealer. I don't want Isuzu to blame the problem on the Injen air intake.

I noticed that beside the engine sound, there is not much difference in the performance and if I had to do it again...I would never install this at the first place. Just because the money spent on the Injen kit was not really worth it.

Michael

[paultvx]

Originally posted by Joe_Black
Intake tubes have to be shielded or insulated to work effectively at delivering cooler air. Believe me, with my Merkur/Sierra experience I've been down this road. If you can keep the radiant and ambient engine bay temps away from your induction components you'll only benefit. It usually isn't very pretty though, with aluminized wraps and metal or ceramic shields all over the place. But you can't go fast and look good under the hood! Well, to the knowledgeable it would look good, but not to the ricer crowd.;pg;

Two words: carbon fiber.

[WormGod]

I dont think I ever noticed any major gain in the HotShot intake myself. I do not recall anyone with it getting a dyno w/ and without it for comparison, so I can only go by my personal driving 7th sense. Other than it being pretty, it just seems like more fluff. *shrug*

[Joe_Black]

Paultvx, carbon fiber is thermally STABLE, not thermally insulative. One reason for its thermal stability is its ability to conduct heat so well. This makes it one of the poorest choices for an induction material.