PVC pipe?

did this to my 86 dodge truck made a noticable difference in performance.

when i did CAI i wasnt checking on my milage, but it sounded good.

required parts
- 2002 ford focus zx3 w/ 2.0 zetec engine
-fiberoptic protective tube(1.5in thick)
tools: drill, cable tie.
actions: drll a hole in the resonator, guide tube to lower grille, ziptie at grille, plug tube into hole in resonator.

@Deadeye

“Bunch of morrons…”
“It’s only becase of their air filter is one of those sporty-high speed air intake.”
“Too bas for them…”

No, “too bas” for you. Your argument that these guys are morons would be much more compelling if you actually spelled the word “moron” correctly.

Your post reminded me of this guy:

http://poleblog.polemos.net/2007/12/dont-be-moran.html

@Deadeye

Not so fast. Colder air = more dense air thus more air molecules per given volume (volume is of course static). More air molecules = more fuel (pcm adjusts fuel in relation to total air MASS) and bingo, more power.

I see nothing special about this at all. I wouldn’t even call it a hack since building one of these is extremely easy, and done every day for performance gains. It’s actually one of the first mods import car guys usually do.

There is no increased wear on the engine, aside from choosing a less effective filter. Cone filters are not less effective than a normal square filter, but a k&n filter does filter less effectively than a paper filter. The benefit is that it flows more air than a paper filter.

All this mod has done is make the intake flow more air at a colder temperature. Definitely a good mod if you’re looking for a minimal gain in power, but there are much better ways to do it.

The correct way is to use mandrel bent aluminium pipe and an intermediate foam filter. That way when you hit a puddle you suck air through the foam filter instead of sucking water up your intake and into your motor.

Then again, it is a Cavalier. Maybe they are trying to hydrolock the engine? I do have to worry a bit about how the PVC will hold up over time, but for pocket change you can rebuild it every year if you need to.

Alex M is correct.
We have been using cold air intakes on our custom builds for years and the dyno results suggest an increase in horsepower, amongst better throttle response. Cold air is especially on forced induction and turbocharged systems.

I am with everyone else. This is the first mod teenage ricers do to their hondas. We were doing this back in the late 90s for christ sake. Come on HAD I miss the old days.

im sorry but i have to say this is not something i ever hope to see on had again.

yes its a good mod, all it is is a pvc air scoop that throws fresh (cooler) air into the engine bay, which in turn has more cooler air available. but to say its a Cold Air Intake is misleading, and to post this up as a ‘hack’ is very discouraging… what will the next automotive hack be, a hacked-off exhaust being listed as ‘high flow’ ?

i just never expected to see the same home depot cavalier mods that clutter up the rest of the net here on had…

The bigger problem is that it’s going to suck in water. The factory box was designed to sift the water out. Water+engine=unhappy

Chrome plated copper pipe is where it’s at.

Was gonna comment earlier but now I have more points to make

So the mod wasn’t the new filter, but the PVC redirecting air flow, right? It’s not clear through the few pictures. Dyno test won’t prove anything – this is a ghetto ram air setup so it relies on the wind coming at the car.

Who knows maybe it increases drag enough to hurt the mileage.

Everyone around here, myself included, used to do this to our cars when we were like 16.

The next step up is that you can trick the car’s computer into thinking the intake air is colder by replacing the sensor with a resistor of the appropriate value, thereby making the engine run rich. I actually had a potentiometer hooked up way back when. Good ol’ days :P

For all the “it’ll suck water” people. I’d agree if the filter was directly attached to the pipe. As I see it, if the pipe got any water in the bottom then the engine will just pull air from the rest of the engine compartment. If the bottom was pointing straight out the front, then maybe, but probably not this setup.

They won’t see an increase in performance or efficiency and now the car is susceptible to puddles.

if you’re making the the pipe running to the intake longer, you’re making it harder for the engine to breath, ie breath in, then try breathing throw a straw, join two straws together, its hard to suck the air in as it gets longer. an na engine is working on atmospheric pressure so its sucking in air as fast as the inlets allow it, in order to equalise out.

If a CAI works, its because the old system wasn’t working properly in the first place, especially on an NA engine.

Usually it just makes it louder, and that makes the butt dyno think its going faster.

@sam

they actually do have systems to cool the air charge even more. CO2 systems that spray the intercooler fins on turbo cars to cool the intake charge even more are available as kits already. There are nitrous kits that do something similar as well. Colder, denser air is always better than hot air. period. It will always produce the most horspower because a colder air charge equals more air and fuel in the combustion chamber.

Wouldn’t it have been better if they used aluminum or some better material that would cool the air a little more? I also think that if they were going to go through that much work they should have done a Ram air / cold air intake for a little extra!!!

It don’t even think this is a cold air intake, its more like a vent to the engine compartment. It just directs air towards the air filter, the stock airbox on my toyota truck is more cold air than this, as it pulls air from inside the fender, instead of inside the engine compartment. I don’t think this could even suck water into the airfilter, its not even sealed, to create a vacuum, that would suck enough water to hydrolock it, from a 3 inch or so pipe its not even directly connected to, seems impossible. Unless I didn’t see all the pictures.

colder air doesn’t always automatically mean more power, its the potential to make more power, power usually comes from spark advance. certainly any noticeable power over whats already going to be a close mix.

the intake manifold is really hot especially at a power level where altering the amount of o2/fuel would even begin to do anything, taking in a slightly cooler charge ends up being even less slightly cooler by the time its gets to the combustion chamber. If the existing setup is pulling hot air in from the engine thats causes it to be significantly higher by the time it reaches the chamber, thats one thing, thats rare, measure the IAT on almost any car at WOT and you’ll see how fast it ramps up.

the ecu runs the car for a given intake temperature at X spark and Y AFR, if its not optimium, it takes it away.

cooler is better, but lengthing pipes, and getting air thats maybe only slightly cooler another.

i’m sure people imagine some massively different explosion going on in the combustion chamber because the air intake is maybe slightly cooler.

Calculate the change in air density and how much of a temperature change you’d need for a typical chamber vs how much extra fuel is added.

maf’s measure air flow not density. tmaf’s measure temperature and airflow, if you tell a maf its flowing less air than you actually are, it could be all sorts of bad, you end up in the deceleration area of the maps and run nowhere near enough fuel and too much timing.

people have been doing this shit for years. that’s not meant to be a negative comment, it’s good that a DIY cold air intake is finally in the HaD archives now. for more PVC fun, try mounting a potato gun on a jeep. ok thats a dumb idea because how you supposed to load it? but automate the loading process (beyond me), automate the filling of combustion chamber(much simpler), then wire the ignitor to the car horn switch :D
now forget that i ever suggested such a destructive idea..

I’ve got a K&N intake on my truck, and whenever we have a cold snap, I have a really hard time not peeling out everywhere. No need for PVC in my case, the kit creates a little compartment in the corner opposite the battery that’s shielded from the rest of the engine compartment, and it gets plenty of air directly from around the headlight.

Speaking of air from around the headlights, this concept is really old- they did a much better job in 1964… http://www.crankshaftcoalition.com/wiki/Cold_air_intakes

I bought a machined aluminum Cold Air Intake from Matrix about 5 years ago for my ’95 Civic EX(VTEC).

$50 for the intake, $15 for the high-flow air filter. Made a world of difference and I don’t have to worry about PVC melting all over my valve cover for only $35 more.

There is a reason they don’t use PVC plumbing pipe for engine components, you know. There are specially made plastics and composites designed for high temperature and high-stress applications like in a car’s engine compartment.

“The best increase in efficiency, though, was changing my driving habbits. I increased my gas mileage by 20% by keeping it under 70, dropping 10 MPH from the bottom of hills to the top, and accelerating very gently.”

Yeah, that does make a huge difference, learning how to use the gas pedal properly. Kind of like learning to use the brakes properly, they last a lot longer with nice smooth stops, instead of last second ones.

@tbase I’m not saying that there are not gains to be had, but your problem with peeling out in cold weather probably has more to do with cold tar and cold tires than it does with the minor gains that you get from a less restrictive air filter.

Thats a nice cold water intake.

Not sure why this is on hackaday. This is the most basic of basic modifications car guys do. I’ll be impressed when they pull off an LNF engine swap. Or turbo that 2.2 engine reliably. Or crack the ECU and remap the air/fuel binaries. This is as much a “hack” as changing spark plugs. Give me a break.

To further M4CGYV3R’s point, PVC has a tendency to harden and breakdown at higher temperatures, letting off potentially dangerous fumes. I’ve yet to see proof of anyone getting hurt by this, but PVC in the engine bay is generally frowned upon.

I like this I have done worse things to my car after a few brews. Such as writing turbo charged on the side of it with a permanent marker.

:S Seems like a lot of people didn’t read the article(errr looked at the photobucket). The pipe just guides cold air into the engine compartment. It’s not connected to the air filter. So there is no chance of sucking up water, etc.

That said, I put a K&N filter in my car a while back, but I went with a stock sized one and kept my airbox. I don’t see how the short ram is beneficial, it’s so close to the engine it’ll just pull in hot air. In my ’97 intrepid the air box pulls air from the fender, so it’s nice and cold already. What I would like is to be able to increase the amount of air it can draw from the fender, I think that’s where more gains are to be had, is having less restrictive flow.

So I might just have to try, but with a dryer hose…Since the general consensus is PVC is a poor choice.

They seem to have done a hell of a lot better than my SLA version. http://i45.tinypic.com/b5mlj5.jpg

This reminds me of the diving helmet from last week. Does anyone else see the arm of a Rock-em-Sock-em-Robot?

No doubt modest performance where realized, as this is a time honored hot rodding mod. But by the seat of the pants data gathering is relative,and should be taken with a grain of salt. As always this could be refined, but if the car owner is happy, that’s all that matters isn’t?

Wow, I took a look at this picture, this guy seriously needs to lose that last 90° bend and put a shield around that cone filter to get the engine bay heat away.

Any decent cone air system has a custom heat sheild so you don’t lose power due to heat-soak under the hood.

Simple works too, get a rubbermaid box and cut out the sides that lead to cold air.

Most hot rodders would simply move the battery to the trunk and remove that headlight (or stealth mod it with a tube going through an unused high-beam area, or even divert some air that direction with a simple metal flap placed behind the grille).

Good for a first attempt hack though, but he didn’t spend much time thinking about how real cold-air systems are designed, or how flow works.

There’s some seriously poor knowledge masquerading as detailed knowledge in this comments thread. It’s no wonder myths and misnomers about car tuning are rife on the internet.

And all of that adds to the fact that, as mentioned, this is a bog standard schoolkid mod to help with a botched filter arrangement. No filter should be open in the engine bay in the first place, that’s the most ridiculous arrangement and I see it day after day as a “performance mod”. Filters, unless placed in front of the rads, in a well considered location, should be in a housing and fed from a cold location. Most stock boxes already do this, at least in european/japanese vehicles, and do this very well. Have any of you actually measured the pressure drop and intake temps across a stock intake setup – they’re actually pretty damn good on most cars. Usually the best solution possible, without completely re-building the intake, is to simply go for a lesser-filtering panel (K&N etc) to replace the stock one and lag the pipework.

So many people assume that stock=compromise, or aftermarket=automatically better, without ever checking to see. The number of people I’ve had to break the news to about how their £100 “induction kit” is actually robbing them of hp (over stock) and then seen it proved on the rollers is quite frightening. I’m not saying stock is always good, or that stock will deal with a seriously modified engine, but at relatively lowly modification, the stock intake usually VERY well thought out and a team of very smart designers with CFD packages have optimised it to suit the engine, unlike the guys who’ll sell you a metre of stainless pipe and a sponge in a strainer.

I don’t know why a lot of people think this will improve gas mileage. Even with colder air, the engine will be still be pulling air mass in at the same rate for a given power output. The car’s computer will keep the air mass to fuel mass ratio where it should be, and the same amount of fuel will be burned.

SLOW DOWN I’M WRITING!!

Sponge and a strainer…DAMMIT

ANYONE HAVE A PEN?????

Weak, on last years’ BABE rally our comrades in team epic fail were having tons of trouble getting their poor Toyota around the mountain roads. We ended up all stopping together to check out why the car was struggling horribly to discover…

There was no air box. NONE no filters no box just a fitting with a few bolts sticking out of it where the motor was sucking in air, to top it off she was sucking hot air from right off the transmission!

Thus ensued a massive cross team effort to empty any plastic bottles in our possessions, cut the tops and bottoms, down the length. some kind of horrible elbow fitting was fashioned, and an aluminum duct tape, plastic, and regular duct tape amalgamation took shape. We found a source of cool(er) air from the fender (likely where the stock air box was sucking from). still no air filter, I think somebody suggested putting a stocking over something..? We tactfully ignored the gravel-sucking design and nothing happened.

Team epic fail had no further problems with the motor bogging down, the new intake took them from the mountains of TN to NO in the middle of the summer. THAT is a hack.

“Your idling air temp will be up a bit, but once you start cruising, within a second or two, the air you’re sucking in drops to the ambient temperature outside.”

Not in my several years of testing, and if it does your radiators are massively larger than required, but I suppose that depends on your airflow arrangements under the bonnet. In most situations you’ll be getting air from the coolant rad, which will be in the region of ambient+30C or so. The OEM pipe is generally perfectly good unless your car was designed by an idiot, and often are shared with the much higher powered variants of the same engine, so more than capable. Your gains from a shorter intake are rarely large enough to compensate for the losses of warmer intake temps, despite what the aftermarket industry will tell you. Sometimes you can place the filter inside the bay but directly behind a large frontal opening that isnt fed by through the rad, which is reasonable, but it still should be boxed in as at any speed where airflow is not appreciable you’re running on hot air.

Such as here (this setup is proven to reduce power with hot underbonnet temps):
http://www.brsf.net/cars/gt4/cel-intwr02.jpg
this is the proper way:
http://homepage.virgin.net/shalco.com/images/celica_eng.jpg

Hackaday really isn’t the place for discussing car mods and thermodynamics.

@ whoever said to use an AFC up there:

That is the most special needs hack of a pos excuse for a tuning device ever. Did you consider what it does to your ignition timing when the ecu is running in a different load cell because the afc LIED to it? I hope some of you geniuses put AFC’s on your cars because you’ll be the guys I’m spanking using only a stock turbo and a real tuning system.

And? Does it use less fuel? I doubt!

@James

“Hackaday really isn’t the place for discussing car mods and thermodynamics.”

I’ve always been disappointed by the lack of ECU and vehicle control systems (how about ABS, traction control, and stability control?) hacking. Sure, there are plenty of commercially available products for ECU tuning, but I haven’t seen many hacks.

I guess the consequences of damaging an ECU or power train (expensive and inconvenient) and possible safety issues (think runaway Toyotas) make this kind of hacking a little beyond Hack A Dayers.

@Jess

Your story reminds me of Apollo 13 ;)

I’ve modded a few cars and been on other forums dedicated to this.

The consensus is that PVC/Duct CAIs don’t work. And guess what, neither do K&N filters.

You can get a high flow MAF and modify the ECM programming. This might give you some measurable gains. You’re better off ripping out your AC system than doing this.

Most cars now are not limited by restricted airflow. Ditching your catalytic converters and a high flow exhaust would gain you HP in the double digits not double decimals.

“Yeah, I’m going to have to go ahead and, yeah, disagree with you there.”

In theory the ECM is going to compensate for the air flow (map sensor) and temperature (intake air temp) and adjust the air/fuel ratio based on these conditions. I would expect the gain to be marginal if measurable at all. Speaking of which, where’s the A/B dyno test?

This hack puts my dual turbofan, bullet-proof Suburban Assault Vehicle to shame.

Lowering the intake temperature yields lower efficiency because the fuel charge then burns at a lower temperature.

Efficiency of the engine, when other variables are removed, is determined by the average temperature in the cylider during power stroke, relative to the temperature of the ambient air around the exhaust. That is, the hotter your intake temperature is, the less fuel you need to use to make the mass of air hot. This is why things like microturbines or stirling engines use pre-heaters for the intake air. A good heat recuperator can double the efficiency of the engine by recycling lost exhaust heat back into the combustion chamber.

Internal combustion engines use intercoolers and generally avoid pre-heating to improve volumetric efficiency, that is, how much air you can cram in the cylinder. It would be theoretically possible to increase the efficiency through pre-heating the air – a turbo does this to some extent – but heat it too much and you’ll burn a hole in the piston.

ROFL look at all these experts in here, get over it. Its a piece of PVC

Hi. Please, how about some math to figure the length of PVC per engine size? I believe this gives a better mod(Hack?), I’ve read something along the lines of 1 inch of pipe length per CC engine size. Obviously taking into account the diameter of the carb. Is this not how one calculates a Ram Air intake? Some maths on this would help. Length of pipe also has something to do with, Where in the power band, the improvement occurs. I think short pipe for low rev range and long pipe for higher. Googling doesn’t throw up much, especially if you don’t know how to ask. Air flow in is at most pressure at the front most point of the vehicle in question. I feel some bonnet scoops are in the wrong place, due to aero dynamics. What do you think?

Cheers Mike