Lower restriction filter / cold air intake = better MPG?

(aside from the obvious tips on driving slower ...)

I've read a number of posts suggesting that a low restriction
cotton-gauze filter can marginally increase fuel economy and power.
I've heard other speak in favor of mods like cold air intake, headers,
cat-back exhaust providing marginal benefit.

Assuming that the maintenance is all kosher and the proper driving
techniques are in place, what mods (in the few hundred dollar range)
would hold some promise of delivering improved fuel economy for an '05
Accord LX i4 M5?
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| Charles Lasitter | Mailing/Shipping |
| 401/728-1987 | 14 Cooke St |
| cl+at+ncdm+dot+com | Pawtucket RI 02860 |
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Perhaps, but then you might shorten the engine's life span since you could
be reducing the filtering capacity of the intake system. If I remember
correctly, there have been some posts on this newsgroup of people stating
that their engines have starting to burn oil after driving around with these
"low restriction" intake systems for a while.

 

That could be one of the reasons every time I am behind one of the garbage
can muffler equipped cars, that I either smell the odour of burning oil or
am at a loss as to where the road is due to the cloud of oil smoke in front
of me.

 

I'm not having that much luck finding empiracle data on this topic,
but this test of K&N filters was a start:

http://tinyurl.com/2jucn

The subject is not without controversy, but I'd love to see more
references to careful testing of the filtration and performance gains.
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| Charles Lasitter | Mailing/Shipping |
| 401/728-1987 | 14 Cooke St |
| cl+at+ncdm+dot+com | Pawtucket RI 02860 |
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We use the endearing term "Honda Turds"....

 

Cold air intake can help increase HP - but also uses more fuel to do it.
Unless the efficiency of the engine has magically improved, you need to put
more energy (gasoline) in to get more energy (HP) out. When you consider
that the engine in your '05 has been finely tuned to give you the best
balance of power, economy and driveability, it's hard to imagine that any
aftermarket bolt-on can do it better. My 2 cents worth.

Doug

 

Fortunately, it's not only Honda products that have this problem.

 

I think you're largely correct, but it's worth bearing in mind that they
are engineering the car for the needs of a mass audience and doing so at
the lowest possible cost.

So in theory, at least, if you were willing to spend hundreds more on
the exhause system, or the air intake system, or another wad on the
suspension system, you might get a car more to your liking in terms of
specific aspects of performance or handling.

If a selective investment gives me a little better fuel economy, or a
little better performance at the same MPG, I'll take that as a win. At
least until I win the lottery, and then I'll forget about all the
tweaking, and just pop for a Beemer 550i.
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| Charles Lasitter | Mailing/Shipping |
| 401/728-1987 | 14 Cooke St |
| cl+at+ncdm+dot+com | Pawtucket RI 02860 |
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WRT cold air intakes,they generate a lot more noise,and auto engineers are
designing for a larger market that would not tolerate the extra noise.
The same goes for low restriction exhaust systems.

 

Here's a better one.
http://home.usadatanet.net/%7Ejbplock/ISO5011/SPICER.htm

A K&N filter will allow lots more dirt into your engine, grinding your
rings, bores and bearings much more quickly. It will increase the amount of
abrasive silica in your oil. It will gum up the IAC/EACV much more quickly.

Any performance gains on a road-going Honda are likely to be measurable
only with a dynamometer. Hondas, like most small-capacity 4-cylinder
engines, do not have excessive intake restriction to begin with.

See my link above. I would NEVER use a K&N on ANY Honda that I intended to
make last for a long time.

 

Everyone agrees that dirt in the oil is bad, and the URL you provided
has information in the form of graphs, which is useful, but here's the
question I have trouble with:

Both had tests with ISO 5011 standards, and page I found used other
standards for additional tests, and the results quoted there cast K&N in
a more favorable light.

So what are the key differences between the tests, and what is the rate
of filtration that Honda sets as "good enough" for its engines? How
does the factory issued filter perform?
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| Charles Lasitter | Mailing/Shipping |
| 401/728-1987 | 14 Cooke St |
| cl+at+ncdm+dot+com | Pawtucket RI 02860 |
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why don't you address the real point? hondas don't have restrictive
intakes unlike say a 5.6L dodge whose ducting is narrower than a 1.5L
civic. "cold air" is mostly unnecessary unless you're right at the top
of the power band. and even then, in my experience, most people that
consider themselves hot-shots off the lights change /way/ too early and
/never/ get into a rev range where there could be any advantage. [not
counting the stock system's advantages of resonance tuning of course.]

i gun my [motor all stock] civic pretty hard, use the full rev range,
and guess what, i can drag most riced civics up to about 60. why?
because i have everything adjusted perfectly, /not/ because i ponce
about with a stupid air intake that i don't need. save your money - use
oem filtration and enjoy both better mid-range performance and longer
engine life.

 

Of course, any gasoline engine running at less than wide-open throttle has
intake restriction, regardless of the air intake or filter... it's called a
throttle plate. Any benefit of intake or exhaust mods can only be felt at
full throttle and high rpms. I've never understood the attraction myself.

Mike

 

I guess you never have removed the intake on one.They are restrictive AND
suck hot underhood air.The intake makes all sorts of turns,has a resonator
tank,and the final duct to the throttle body is corrugated,not smooth.

Again,not true.I got much better low-end performance on my 94 Integra
GSR,with a $60 chinese CAI off Ebay.It's filter is as good as the OEM
filter.IIRC,they use the same material.
You could feel the difference in performance.

 

to add to my previous post;Honda Tuning Magazine flowbench and dynoTESTED
CAIs and short ram intakes and documented the power and torque gains.
With a benchmark test of the OEM system to compare against.

 

altering the length of the intake alters the HP and torque at any given
RPM,and ingesting colder air allows the ECU to add more fuel,making more
power,regardless of what RPM.
Honda Tuning Magazine's dyno test graphs showed that,in their intake
systems testing a couple of years ago.

 

You're missing the point of the OP - he wants a little more power and a
little better economy. If "colder air allows the ECU to add more fuel" he's
going to lose MPG, not gain. The point of whether or not he gets more HP out
of a CAI is moot.

Doug

 

In addition to the advertising hype there are obviously different
opinions on the issue of filters and CAIs, and this exchange of views is
almost exactly what I was hoping for.

I'm really not expecting any of these mods to pay for themselves in
terms of fuel economy, and I am not interested in HP gains that are so
small they can be measured on a dyno but not felt.

The factory setup is almost always going to be best for the largest
number of drivers, and I appreciate your comments.

One thing I find curious is the absence of CAI listings for '05 2.4L
Accords. I was just out trying to follow the air inlet path, and it
seems to end just forward of the drivers front wheelwell.

It's shielded, no doubt to protect against water ingestion, but it seems
that this location would normally provide it with a source for
(relatively) cold air.
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| Charles Lasitter | Mailing/Shipping |
| 401/728-1987 | 14 Cooke St |
| cl+at+ncdm+dot+com | Pawtucket RI 02860 |
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You don't get increased power AND increased fuel economy at the same time.
However,having more power output at a given throttle opening,you can back
off on the throttle and use less fuel and not suffer a performance
loss(from original).
With the added benefit of having more power available when wanted.

IMO,driving -style- is more influential on fuel economy,gentler starts and
coasting when possible do more for fuel economy than any mods.
Sure,he could strip out excess weight like insulation,unused seats,clean
out the trunk,no spare tire,but that's impractical.(and unwise)

 

Honda Tuning Magazine's tests got 20 hp gains on an RSX with the CAIs,5-7
hp with short rams.I could definitely feel the gain on my GSR after the CAI
was put in. IMO,a short ram was not worth the trouble or cost.

Like in my Integra,you may find that the intake curves UP into the top of
the fender and back into the engine compartment,along with a resonator tank
in that wheelwell area.The Type-R difference is that the pipe ends at the
top inside of the fender,not reentering the engine compartment.The length
of the intake piping increases low-end torque,I've read.

Not when the pipe loops back into the engine compartment.(like my Integra)

One Integra modder had a diagram of the Integra intake plumbing on their
website,and a copy of the Type-R's intake,too.