Aftermarket intake questions

Alan Baker > wrote:

>In article >,
> (Leon van Dommelen) wrote:
>
>> "Dana Rohleder" > wrote:
>>
>> >So are you saying, that makers of competition and high-performance engines
>> >have been hurting themselves by removing stock air cleaner/filter assemblies
>> >and installing ram-air systems, superchargers, etc.?
>>
>> No I am not. As I tried to explain, admitting cooler air in the intake
>> system
>> will reduce the flow efficiency, since the throttle is further closed,
>> increasing fuel consumption by increasing pumping losses.
>
>So admitting warmer air would then *increase* flow efficiency?
>
>Sorry, Leon, you're just wrong.

No.

>>
>> The reduction of explicit flow restrictions *at given performance* does
>> nothing.
>> If you reduce the flow restriction elsewhere in the intake system, you will
>> need to close the throttle more to keep the performance the same.
>
>Or leave the throttle the same to get more performance...
>
>
>...which is what we're after, right?

No. Why don't you first read the thread before replying to it.

>>
>> *Supposedly* these devices are to increase *maximum* performance, i.e. power
>> with the throttle wide open. But Lanny may well be right in noting that most
>> just reduce maximum performance too. As I noted in another post, if you mess
>> around with the intake, you lose any design optimizations Mazda may have
>> done.
>> In particular, acoustics is a confounding factor, since the speed of sound
>> does not cooperate and go up proportional to engine speed.
>
>Do you really understand what you just said?

Yes. It is a simple similarity (or dimensional, if you want) argument.

Leon
--
Leon van Dommelen Bess, the Miata Bozo, the Miata
http://www.dommelen.net/miata
The only thing better than a white Miata is two white Miatas

"Dana Rohleder" > wrote:

>"Leon van Dommelen" > wrote in message
.. .
>> "Dana Rohleder" > wrote:
>>
>>>So are you saying, that makers of competition and high-performance engines
>>>have been hurting themselves by removing stock air cleaner/filter
>>>assemblies
>>>and installing ram-air systems, superchargers, etc.?
>>
>> No I am not. As I tried to explain, admitting cooler air in the intake
>> system
>> will reduce the flow efficiency, since the throttle is further closed,
>> increasing fuel consumption by increasing pumping losses.
>
>Since when does closing a throttle increase fuel consumption?

Since pretty much the beginning of internal combustion engines. As
long as it is at given power.

> Cooler air
>into an engine simply means combustion will be more complete because of the
>higher amount of oxygen in the air per unit volume.

No. On a modern engine, the ECU adjusts the fuel to the amount of
oxygen present. So it would increase performance. Hence the need
to reduce throttle if performance is to be the same.

> It doesn't affect the
>throttle at all. If the ambient O2 in the air is too high (virtually
>impossible unless you are injecting it), the oxygen sensor in the exhaust
>will sense any unburned oxygen in the exhaust gas and send this info to the
>ECM to adjust timing/mixture, etc., but that is again uncombusted oxygen in
>the exhaust, not incoming oxygen at the intake side. The MAS on the intake
>attempts to measure air volume and temperature, but doesn't measure actual
>oxygen content.
>
>> The reduction of explicit flow restrictions *at given performance* does
>> nothing.
>
>This statement must assume that the "explicit airflow restrictions"
>(whatever they are)

Head losses due to the basic geometry, i.e. at constant throttle.

Head loss is the official word for the effect of flow restrictions. (Which
are most of the time differences in pressure, rather than velocity, as you
seemed to think in an earlier post.)

> are not hindering the system's performance in the
>control situation. But if airflow restrictions in the control setting are
>choking the combustion air to the system causing it to underperform, then
>allowing the air through by reducing the restrictions would allow the system
>to perform better, would it not?

Please read again all my original posts. The performance was to be held
*constant*. If you want to drive a given speed, performance (or to be precise,
engine horsepower output) is given, not something to be optimized. Fuel
consumption is then to be optimized, and that is a very different matter.

> This is the assumption the ram intake
>manufacturers make - that the stock system has inherent restrictions that
>keep the engine from performing at optimal levels.
>
>> If you reduce the flow restriction elsewhere in the intake system, you
>> will
>> need to close the throttle more to keep the performance the same.
>>
>
>So, as my stock air cleaner element becomes more clogged with dirt,
>(reducing airflow - agreed?) I will need to reduce my throttle to keep
>performance the same?? Put another way, the more restricted my airflow, the
>better?!?
>
>
>> *Supposedly* these devices are to increase *maximum* performance, i.e.
>> power
>> with the throttle wide open. But Lanny may well be right in noting that
>> most
>> just reduce maximum performance too. As I noted in another post, if you
>> mess
>> around with the intake, you lose any design optimizations Mazda may have
>> done.
>> In particular, acoustics is a confounding factor, since the speed of sound
>> does not cooperate and go up proportional to engine speed.
>
>I agree that most auto manufacturers are going to tune their entire
>drivetrains to achieve a particular goal in many categories, ie. fuel
>economy, driveability, torque curve, horsepower, noise emissions,
>hydrocarbon emissions, etc. However, that doesn't mean that you still can't
>improve some parameters, albeit at the possible reduction of others. My
>initial question to the group was, who has tried an aftermarket intake, and
>what was the result?

In your original post you stated,

"Logic tells me that the intake would increase the fuel economy even more."
and I asked "What logic?"

If you check the subthread you are responding to, you will find that this is
the issue under discussion, not maximum horsepower that the engine can produce.

> My intention was to get actual information from people
>who have actually tried these systems, not to spend a bunch of everyone's
>time mentally masturbating in a virtual circle jerk.

I did not make any personal remarks at your address. Why do you do it at mine?

Leon
--
Leon van Dommelen Bess, the Miata Bozo, the Miata
http://www.dommelen.net/miata
The only thing better than a white Miata is two white Miatas

"Usenet" > wrote:

>Ok, so let me get this straight. First off, the EPA is wrong when they list
>replacing a dirty air filter as the number 2 way to improve gas mileage?

No. Parts that are out of spec will normally increase fuel consumption.

>http://www.fueleconomy.gov/feg/maintain.shtml
>
>Second, all the dyno tests in the car rags and TV shows are wrong (e.g.,
>installing less restrictive air intakes delivering cooler air to the engine
>don't increase horse power)?

Same response as to Alan Baker.

Leon

>Third, Wikipedia is missing the boat since it does not reference any of the
>negative theories (e.g., loss of "maximum power", " loss of fuel
>efficiency", etc.)?
>
>http://en.wikipedia.org/wiki/Cold_air_intake
>
>Finally, the only real answer to these questions is actual test data whether
>dyno testing or actual driving. Anybody out there have any actual data?
>
>Gus
>
>P.S. My 91 with over 210,000 miles doesn't use significant oil, still shows
>good compression, and drives just fine even though I've been using a K&N
>filter, which is cleaned and reoiled every 30,000 miles.
--
Leon van Dommelen Bess, the Miata Bozo, the Miata
http://www.dommelen.net/miata
The only thing better than a white Miata is two white Miatas

In article >,
"Usenet" > wrote:

> Second, all the dyno tests in the car rags and TV shows are wrong (e.g.,
> installing less restrictive air intakes delivering cooler air to the engine
> don't increase horse power)?

If they were testing a Miata, probably so. Other cars may benefit from
less-restrictive intakes, but it's a mistake to assume a Miata will. You
can't fix a problem that doesn't exist. Cooler air can help reduce power
loss in hot conditions, a good thing for sure, but is unlikely to
generate an actual increase. Note that a true cold air intake must be
sealed from ingesting underhood air, not just have a heatshield.

Even so, a "dyno test" is highly suspect when the aftermarket
manufacturer's full-page ad is on the facing page. If you think car
magazines are more about truth than marketing, you're forgetting who
pays the magazine's staff. Hint: it ain't you. The cover price is
typically less than the cost of printing and distribution.

In article >,
(Leon van Dommelen) wrote:

> Alan Baker > wrote:
>
> >In article >,
> > (Leon van Dommelen) wrote:
> >
> >> "Dana Rohleder" > wrote:
> >>
> >> >So are you saying, that makers of competition and high-performance
> >> >engines
> >> >have been hurting themselves by removing stock air cleaner/filter
> >> >assemblies
> >> >and installing ram-air systems, superchargers, etc.?
> >>
> >> No I am not. As I tried to explain, admitting cooler air in the intake
> >> system
> >> will reduce the flow efficiency, since the throttle is further closed,
> >> increasing fuel consumption by increasing pumping losses.
> >
> >So admitting warmer air would then *increase* flow efficiency?
> >
> >Sorry, Leon, you're just wrong.
>
> No.

Yes.

If you argue that admitting colder air would decrease flow efficiency
then you're also arguing that admitting warmer air would increase it.

>
> >>
> >> The reduction of explicit flow restrictions *at given performance* does
> >> nothing.
> >> If you reduce the flow restriction elsewhere in the intake system, you
> >> will
> >> need to close the throttle more to keep the performance the same.
> >
> >Or leave the throttle the same to get more performance...
> >
> >
> >...which is what we're after, right?
>
> No. Why don't you first read the thread before replying to it.

Please feel free to quote anything you think I should have read.

>
> >>
> >> *Supposedly* these devices are to increase *maximum* performance, i.e.
> >> power
> >> with the throttle wide open. But Lanny may well be right in noting that
> >> most
> >> just reduce maximum performance too. As I noted in another post, if you
> >> mess
> >> around with the intake, you lose any design optimizations Mazda may have
> >> done.
> >> In particular, acoustics is a confounding factor, since the speed of sound
> >> does not cooperate and go up proportional to engine speed.
> >
> >Do you really understand what you just said?
>
> Yes. It is a simple similarity (or dimensional, if you want) argument.

Sorry. That's obfuscation, not explanation.

--
Alan Baker
Vancouver, British Columbia
"If you raise the ceiling four feet, move the fireplace from that wall
to that wall, you'll still only get the full stereophonic effect if you
sit in the bottom of that cupboard."

Usenet wrote:
> P.S. My 91 with over 210,000 miles doesn't use significant oil, still
> shows good compression, and drives just fine even though I've been
> using a K&N filter, which is cleaned and reoiled every 30,000 miles.

Just out of interest, how many of those miles were with the K&N filter?
I've just bought one (Typhoon) so anything that makes me feel happier about
it's filtering ability is good

R.

"Leon van Dommelen" > wrote in message
...
> "Dana Rohleder" > wrote:

Leon,

>>My
>>initial question to the group was, who has tried an aftermarket intake,
>>and
>>what was the result?
>
> In your original post you stated,
>
> "Logic tells me that the intake would increase the fuel economy even
> more."
> and I asked "What logic?"

True. What you did was obfuscate a simple question by attempting to send the
discussion in several directions that do nothing to answer the inital
question(s). If you don't have an answer to the question(s) asked, why do
you hinder the process by confusing the isuue - answering simple questions
with divergent questions? I have plenty of my own reasons for not purchasing
a system to date; I am simply trying to get real-life information/data from
owners who have actually tried the systems and have opinions on the results.

>> My intention was to get actual information from people
>>who have actually tried these systems, not to spend a bunch of everyone's
>>time mentally masturbating in a virtual circle jerk.
>
> I did not make any personal remarks at your address. Why do you do it at
> mine?

I was talking about myself starting a useless thread - why would YOU take
the comment personally?
--
Boreal
2001 LS 6 speed Silver/tan, Sport Suspension w/hard rear sway bar

Richard Phillips wrote:
>
> I'd be very interested to see the results, if you could post them up!
>
Here is an appetizer: http://users.cybercity.dk/%7Edsl45720/rulle.JPG

It's the test before any changes so we are talking a 1999 1.8 with
aprox. 60,000 miles on the clock and no alterations to Mazda specs
except it has a Remus exhaust.


> I've just got myself a 2nd hand (6 months old) Typhoon for my 2002 1.8,
> hopefully I'll be fitting it in the next couple of days. I'm not expecting
> anything spectacular but I was curious and I got it much cheaper than new
> price, I just had to scratch the itch, you know?!
>

Supposedly it's real easy to fit so if you got it cheap there certainly
is no reason not to try. Just make sure to keep the original parts in
case you don't like the new sound (or performance somehow suffers).

Kind regards
Bruno

"Richard Phillips" > wrote in message
...
> Usenet wrote:
>> P.S. My 91 with over 210,000 miles doesn't use significant oil, still
>> shows good compression, and drives just fine even though I've been
>> using a K&N filter, which is cleaned and reoiled every 30,000 miles.
>
> Just out of interest, how many of those miles were with the K&N filter?
> I've just bought one (Typhoon) so anything that makes me feel happier
> about it's filtering ability is good
>

I bought the car with just over 100,000 miles over 7 years ago and installed
the K&N soon there after. So, the K&N has been running in the car for over
100,000 miles.

Gus

There is simply too much obfuscation so, I'm starting with a clean slate.
What I hear Leon saying is that at any given velocity of a car, lets say a
Miata for interest of this group, the power output from the engine is the
same, assuming all other external factors are the same (e.g., engine
modifications don't change the profile and thus the drag of the car).
Also, assuming similar fuel mixture in the combustion chamber (which is
controlled by the ECU to meet exhaust and performance criteria), the amount
of air entering through the intake system stays the same (e.g., same power,
same fuel to air ratio, and therefore same air volume). Thus, the throttle
plate in the air intake will be further closed in a less restrictive air
intake system compared to stock.

Now for the difficult part. I believe Leon is stating that at constant
power output, the engine with the less restrictive intake system will need
to work harder to pull in the air due to lower vacuum needed to pull the
same volume across the trottle plate. Put another way, more fuel is needed
to the same net power output to the wheels since more power is used to pull
air into the enginer. If this is the case, then I can understand Leon's
argument. For maximum fuel efficiency, the intake system should be designed
to minimize pumping losses at the designed optimum speed.

What I don't understand, is why moving restriction from the intake system to
the throttle plate results in the engine having more pumping losses. I
understand that the pressure loss across the throttle plate will increase,
but at the same time, the pressure loss across the rest of the system is
less. Therefore, couldn't the vacuum down stream of the throttle plate to
be the same in both cases. Why isn't it the other way around where the
restriction across the throttle plate actually results in less total
pressure drop than the restricted intake system?

Now, of course, this entire argument is only valid for the steady state case
(e.g., the car at constant velocity and the engine at constant power
output). From my experience, even at what appears to be constant velocity
(e.g., driving on the highway at say 65 miles per hour), the engine output
varies to adjust for other factors (e.g., incline of the road, wind, passing
cars, etc.). Average fuel consumption is thus the average overtime as the
engine output and thus fuel efficiency vary to maintain constant speed.

Gus