Autoblog Project Garage: Cold-air intake, Part I
In the quest to improve performance, few modifications provide the horsepower-per-dollar payback of a proper cold air intake. The issue here is that the factory usually designs for a different set of priorities than us enthusiasts hold dear; that in itself isn't evidence of poor engineering, but trade-offs are often embraced by those of us looking to go fast. In other words, this modification isn't for everyone, but it can reward handsomely.
For the price of a couple hundred bucks, an hour or so of your time, some increased maintenance effort in the future, and a the loss of some foul-weather tolerance, you too can enjoy the benefits of additional fresh air.
The first photo in this post represents what our 1996 Impala SS looked like about eight years ago; one of our first modifications was to yank both resonators and replace them with a K&N conical filter and some PVC sewer pipe, as shown below.
This setup has served well in front of two engines and several different levels of build-up, but it has the distinct draw-back of sucking in a lot of hot air from the underhood area. As well, the filter resides in some real estate that we wanted to use for some other items (it's hinted at in the photo, so keep your eyes peeled for some additional posts in the future).
To remedy the issue, we investigated a variety of cold air intakes, and ended up with the "Ram Air Induction System". It uses a scoop mounted in the front lower air dam to pull in cool air, and routes the intake charge to the throttle body using the vast space between the rear of the radiator and the front of the engine. Seriously - there's enough room to stand in between the water pump and electric fan assembly.
Here's what the system looked like after we cut open the box and rifled through the contents a bit.
Needless to say, caution is required during the unpacking process to ensure removal of all packing material.
We officially kicked off the project by yanking the old filter and air tract.
Next, we remove the mass airflow sensor (itself a larger part, swiped from a GM F-body) from the old intake. The rest of the pieces were then set aside (meaning that the stuff got stuck on whatever shelf happened to be clean at the time).
Do not anger the twin 58mm throttle bodies, lest they consume all of your air. And yes, we really need to find some stainless steel cap screws to replace the rusty eyesores that BBK included with the throttle body.
Our next task was to mark the location of two holes that will be punched in the intake elbow. Wait - why would we be attacking our new intake with a drill bit?
Oh - there's the answer, and the makings of several future Project Garage write-ups.
To make life easier, a large C-clamp was used to flatten a section of the elbow. Note the T56 transmission mainshaft assembly in the background.
A bit of masking tape was used to protect the powdercoat finish.
Using a vise to hold the C-clamp makes life a bit easier for those that don't have three hands.
There we go - a nice flat spot, and almost where we wanted it! Hey, no one here claims to be an expert sheetmetal guy.
A view from the underside.
We tried to use the C-clamp method for the second flat, but it failed miserably. The ball peen hammer never lets us down, so we put it to work with a bit of help from a propane torch. That did a number on the powercoat.
A quick hit of semi-gloss black spray paint makes things look all better again.
A horrendously expensive Uni-Bit - worth every penny - was then employed to punch the required 9/16" holes in the intake elbow.
Here's what the throttle body will get to stare down for the rest of its life.
And here's a shot from the side. Yes, we mocked up the assembly underhood, and yes, it looks like everything will fit, thanks to those trick Aeroquip right-angle fittings.
Since we're not quite ready to play with the spray just yet, a pair of 1/8 NPT plugs go into the bungs, and seal up with the assistance of some Teflon pipe compound.
Stay tuned for Part II, where we install the hardware on the car.
This setup has served well in front of two engines and several different levels of build-up, but it has the distinct draw-back of sucking in a lot of hot air from the underhood area. As well, the filter resides in some real estate that we wanted to use for some other items (it's hinted at in the photo, so keep your eyes peeled for some additional posts in the future).
To remedy the issue, we investigated a variety of cold air intakes, and ended up with the "Ram Air Induction System". It uses a scoop mounted in the front lower air dam to pull in cool air, and routes the intake charge to the throttle body using the vast space between the rear of the radiator and the front of the engine. Seriously - there's enough room to stand in between the water pump and electric fan assembly.
Here's what the system looked like after we cut open the box and rifled through the contents a bit.
Needless to say, caution is required during the unpacking process to ensure removal of all packing material.
We officially kicked off the project by yanking the old filter and air tract.
Next, we remove the mass airflow sensor (itself a larger part, swiped from a GM F-body) from the old intake. The rest of the pieces were then set aside (meaning that the stuff got stuck on whatever shelf happened to be clean at the time).
Do not anger the twin 58mm throttle bodies, lest they consume all of your air. And yes, we really need to find some stainless steel cap screws to replace the rusty eyesores that BBK included with the throttle body.
Our next task was to mark the location of two holes that will be punched in the intake elbow. Wait - why would we be attacking our new intake with a drill bit?
Oh - there's the answer, and the makings of several future Project Garage write-ups.
To make life easier, a large C-clamp was used to flatten a section of the elbow. Note the T56 transmission mainshaft assembly in the background.
A bit of masking tape was used to protect the powdercoat finish.
Using a vise to hold the C-clamp makes life a bit easier for those that don't have three hands.
There we go - a nice flat spot, and almost where we wanted it! Hey, no one here claims to be an expert sheetmetal guy.
A view from the underside.
We tried to use the C-clamp method for the second flat, but it failed miserably. The ball peen hammer never lets us down, so we put it to work with a bit of help from a propane torch. That did a number on the powercoat.
A quick hit of semi-gloss black spray paint makes things look all better again.
A horrendously expensive Uni-Bit - worth every penny - was then employed to punch the required 9/16" holes in the intake elbow.
Here's what the throttle body will get to stare down for the rest of its life.
And here's a shot from the side. Yes, we mocked up the assembly underhood, and yes, it looks like everything will fit, thanks to those trick Aeroquip right-angle fittings.
Since we're not quite ready to play with the spray just yet, a pair of 1/8 NPT plugs go into the bungs, and seal up with the assistance of some Teflon pipe compound.
Stay tuned for Part II, where we install the hardware on the car.
Reader Comments (Page 1 of 2)
sl8anic 12:14PM (4/09/2007)
Fine and dandy until ECU re-learns and updates fuel maps. Then it's back to (almost) square one. Well, maybe the intake will be a little louder...
Reply
jj 12:19PM (4/09/2007)
It should be said that different engines will respond to this much differently. For example, and K-series Honda engine really appreciates the cooler air while not much difference will be seen on a D-series. Also depending on the flow and position of the stock unit, and aftermarket one may or may not provide much difference.
and, #1, nope, sorry, some (all?) benefit will remain. Colder air is denser air, period.
Reply
Cornelius 12:28PM (4/09/2007)
Not trying to sound obvious, it is possible on some engines (especially w/ forced induction) that the engine may run too lean with colder/denser air. It's good to do this mod with some engine management to make the mixture run a little richer so you experience better hp gains and don't run the risk of blowing your engine.
Reply
Will 6:22PM (4/09/2007)
A shame about having to resort to a ball-peen hammer, but a nice writeup nonetheless. Having been part of the first group of enthusiasts to try AirAid's HHR 2.4L short ram intake, I felt obligated to provide fellow HHR owners dyno numbers for the product, and after the rolling-road tests, got 8whp and 6lb-ft with the product. The gains were much higher on my 300C, with a K&N Typhoon intake, the results were 20whp and 17lb-ft.
I look forward to your follow-up articles, especially how your NOS install pans out.
Reply
Eric Elinow 1:25PM (4/09/2007)
In accordance with jj's (#2) response, difference engines are affected in very different manners. My 2005 Chevrolet Optra's weak point is the intake system. Its U20SED motor, an Opel/Vauxhall GM Family II Motor has been around in one form or another for several decades and adding a less restrictive intake does wonders for it, resulting in a 5% power increase at the wheels (dyno verified).
Some of my previous vehicles didn't respond as well to this kind of upgrade, but rest assured, its a worthwhile venture given the low cost to potential gains factor. There is still the noise factor, and low to middle throttle levels, the growl is more apparent, but at wide-open throttle, it can be downright deafening. Obviously if the vehicle packs more sound deadening material in the engine bay/hood underside/firewall, this effect will be diminished.
Eric
http://www.europeanisation.net
Reply
Mike 12:56PM (4/09/2007)
I agree with sl8anic...without a reflash, all you're going to get is a nice growl from under the hood, and maybe better gas mileage at highway speeds. The butt dyno isn't going to register any power increases.
But...a few runs on a real dyno with a minor reflash, and *now* we're talking! :)
Reply
felipe 12:58PM (4/09/2007)
best thing i ever did to current my car.
wish i found out about years ago, i would have done this on my acura.
also,disconcect your battery, to rest computer/ecu to help prevent 'check engine' lights.
some cars my still need a tune, but any car will adjust.
throttle response is great.
greatly increases throttle response
Reply
Carlos 1:01PM (4/09/2007)
Excellent point about cars being well designed from the factory, but with different priorities in mind. Plenty of people insult modders saying that the factory engineers know best... but they have to design within specific parameters: cost, quietness, low-rpm-biased powerband, emissions, idiotproofing (eg waterlock), etc.
It's less true of sports cars; there isn't much engine performance to be squeezed out of a Miata or an S2000 with cheap mods for example... they're already tuned aggressively. But a Civic has a lot of untapped potential, locked away to appease the mass market.
Reply
vectorbug 1:02PM (4/09/2007)
I'm not a car expert, but I know a few things, just like most car enthusiasts. However, I don't really see how this is a useful tutorial. For starters, its being done on a really obscure car, theres nothing wrong with that per se, but for the sake of a performance upgrade tutorial, whos going to be CAI'ing a 96 Impala? Maybe Tyrone from Shipping.
Then nothing is really explained regarding the two parts being installed on the elbow pipe, just "Oh - there's the answer, and the makings of several future Project Garage write-ups." ok... and? Although I am humble enough to admit, I'm probably the only person who doesnt know what those parts are. Did they come with the kit? Are they an impala thing?
The last thing that uselessly distracted from the tutorial was the comment about the transmission in the background "Note the T56 transmission mainshaft assembly in the background.". Why are we noting this? What does it have to do with the CAI modification? Again, is this an Impala thing that I am missing here?
I really enjoy autoblog, I do and I mean no disrespect, and I appreciate that you guys are trying to keep it real like jalopnik (you will know us by the trail of parts), but of all the cars to feature a CAI tutorial, that features other unexplained parts being installed, on a car that is more show than go, that isn't even a full tutorial, really is not the most useful article that it could be.
Reply
felipe 1:11PM (4/09/2007)
guys,
you dont need to reflash.
thats like saying you need a reflash everytime the temperature changes from summer to winter, or air pressure changes greatly.
MIKE, not register power increases? obviously you never put one on your car. its minimal, but throttle response is better, sound is fantastic, and a little better milage. just ask k&n
http://www.knfilters.com/search/hp_search.aspx
Reply
Eric Bryant 1:27PM (4/09/2007)
Folks, there will be no PCM relearning going on in this application. The primary purpose of this modification is to increase the airflow and thus increase the maximum obtainable manifold absolute pressure via the reduction of pressure losses across the intake tract, thus improving power. The end goal is *not* to lean out the mixture or anything like that.
This particular PCM uses a mass airflow sensor which directly measures the incoming airflow and injects the appropriate amount of fuel, and therefore there's no trickery in getting it to acknowledge the improved airflow. The situation is likely different with speed density engine management systems, but that's not what we're using here.
With regards to reflashing the PCM, this car has already received a bored and stroked lower end, ported heads and intakes, a rather large cam with about 30 degrees more duration than the stocker, and has seen the stock automatic swapped out for a six-speed manual. In other words, it's already received recalibration far more extensive than what we're talking about here, and seeing how I did all 25-30 reflashes myself, I think I've understood the concept ;)
Reply
Eric Bryant 1:31PM (4/09/2007)
Oh, and with regards to intake noise - that might be of interest with a stock exhaust system (and, indeed, the first induction system I did on the car did add a nice bit of snarl under the hood). But with a 11.7:1 396 breathing through headers and a pair of dual-chamber mufflers, intake noise just doesn't contribute much to the soundtrack at 6500 RPM and WOT ;)
Reply
Phillip 3:16PM (4/09/2007)
Some of you guys are clueless.
My 96' Impala put down 230rwhp stock and that was bumped up to 246rwhp with a K&N intake on the same day.
Reply
scopkins 2:28PM (4/09/2007)
I think you might have been a bit better off to do do the two flat spots and fittings on the sides across from one another. That lines up two the valves on your throttle body far better, and avoids the use of the ball-peen.
I think you probably lost as much airflow as you gained by banging a huge dent in the smooth curve of that elbow.
Too late now, huh?
Reply
felipe 3:09PM (4/09/2007)
yea, nice dents, so much for smooth flow. should have just reused the MAF section and attached pipe on each end.
Reply
Eric Bryant 3:30PM (4/09/2007)
"I think you might have been a bit better off to do do the two flat spots and fittings on the sides across from one another."
Nope, that wouldn't have worked well - each of the two nozzles are going to be assigned to a stage, and so what you suggest would result in a potential imbalance in fuel and nitrous flow when only one stage is operating.
"I think you probably lost as much airflow as you gained by banging a huge dent in the smooth curve of that elbow."
First, the dent ain't exactly "huge", although I will concede that its placement on the outside radius of the elbow is far from ideal, as that's the section of the pipe that supports most of the airflow as the airflow rounds the bend. Second, the 4" elbow has a cross section of over 12.5 square inches, or nearly 50% larger than that of the throttle bodies. A bit of reduction in cross section won't result in meaningful restriction.
"Too late now, huh?"
Wrong again - that's just a chunk of 4" steel elbow, and a run to anyplace that sells parts for heavy-duty trucks will net me all of those I could ever want.
Geez, you folks act like things can never be undone.
Reply
Non-Bizarro Adam 3:37PM (4/09/2007)
Eric,
Although I am with you on the fact that some of the guys here are being a little harsh, I do have to say that you are usually a little more descriptive in each caption. I would have expected you to at least explain the large dent's minimal impact on airflow, even if you were being coy about the N02 in an attempt to preserve a later article.
And to the guy who complained about the Impala being obscure, one of the great things about reading about upgrades to the Impala is that it has a Small-block Chevy motor in it, the most prevalent engine in America. Because of that, most of the upgrades made to this car will also benefit a wide variety of other cars, from Vette's to Camaros to Trucks to Buick Roadmaster Station Wagons (one of my favorites).
Reply
mikeb 3:52PM (4/09/2007)
NICE. ill trade you guys my bike for that car
Reply
Mike 4:20PM (4/09/2007)
The point of the article is that some cheap horsepower is available in a relatively easy to install package and is made for just about every vehicle out there.
Of course the tradeoff is slight noise increase on your stock car, the possibility of hydrolocking your engine should you run through a large puddle of water, increased need to check the air filter, and potential MAF contamination from the oil on the K&N filter (normally from over oiling the filter after cleaning it) but if your into modifying your car, you probably pay more attention to maintenance and will be more diligent to take care of such things (and avoid driving in the rain or at least large puddles).
Also, I'm not sure about the Impala, but there are companies such as C&L who make inlet elbows for Mustangs with flat spots already machined in for nitrous, it makes life easier.
Reply
Chris 4:18PM (4/09/2007)
I have an older car with a Mass flow sensor on the intake, so how would that adjust to more cold air coming in? My understanding is it would read "this air is more dense so I don't need as much fuel." Would this improve things or do I have it backwards?
Reply