Aftermarket intake questions

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.?


>>Less restricted airflow to the engine

>
> More restrictive airflow. If you take in cooler air, it is denser.
> Hence for the same performance, you need to increase the intake
> vacuum. That increases pumping losses.

TO the engine, not IN the engine. The idea is, when the throttle opens
requesting more air to add to the mixture, a properly designed intake would
be able to provide it more efficiently than a restrictive, tortuous intake.
That's why we change air filters, to reduce the restriction caused by dirt
in the filters. Less restriction = more available air delivered to the
throttle when it is needed.

>> performance is
>>enhanced. I'm not saying it's true - that's why I'm asking. But the
>>manufacturers and many owners seem to think so.
>
> What manufacturers? Mazda?

No, the manufacturers of the after-market intakes, and people trying to get
more performance/power from their engines. Stock intakes nowdays are
designed with acoustic chambers to reduce ambient noise, as well as small
air intakes feeding rectangular filter chambers that again feed round and
oval-shaped intake tubes, eventually feeding into a round intake at the
throttle. It is generally accepted that these transitions from one shape to
another with various diameter and direction changes tend to disrupt the flow
of the air making the airflow less efficient and slowing the velocity of the
air delivered to the throttle.

In article >,
"Dana Rohleder" > wrote:

> It is generally accepted that these transitions from one shape to
> another with various diameter and direction changes tend to disrupt the flow
> of the air making the airflow less efficient and slowing the velocity of the
> air delivered to the throttle.

It may be "generally accepted," but on Miatas it's generally wrong. Most
aftermarket intakes result in a power loss, since the OEM intake flows
better than the MAF (1.6) or MAS (1.8). But by all means replace your
paper filter if your goal is more dirt in the engine.

Lanny Chambers wrote:
>
> It may be "generally accepted," but on Miatas it's generally wrong. Most
> aftermarket intakes result in a power loss, since the OEM intake flows
> better than the MAF (1.6) or MAS (1.8). But by all means replace your
> paper filter if your goal is more dirt in the engine.

My 1999 NB 1.8 was on a rolling road a month ago and I plan to
experiment with a K/N Typhoon kit shortly. Once it's mounted I'm gonna
put the car on a dyno again so if anyone is interested I shall post the
results.

Kind regards
Bruno

Bruno wrote:
> Lanny Chambers wrote:
>>
>> It may be "generally accepted," but on Miatas it's generally wrong.
>> Most aftermarket intakes result in a power loss, since the OEM
>> intake flows better than the MAF (1.6) or MAS (1.8). But by all
>> means replace your paper filter if your goal is more dirt in the
>> engine.
>
> My 1999 NB 1.8 was on a rolling road a month ago and I plan to
> experiment with a K/N Typhoon kit shortly. Once it's mounted I'm gonna
> put the car on a dyno again so if anyone is interested I shall post
> the results.
>
> Kind regards
> Bruno

I'd be very interested to see the results, if you could post them up!

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?!

R.

Lanny Chambers wrote:

> It may be "generally accepted," but on Miatas it's generally wrong. Most
> aftermarket intakes result in a power loss, since the OEM intake flows
> better than the MAF (1.6) or MAS (1.8). But by all means replace your
> paper filter if your goal is more dirt in the engine.

Exactly.

Lanny, I don't disagree with EVERYTHING that you say.... :-)

Even after that tire debate, I am probably going to go with the Toyos on
my 16X7 SSRS, complimented by your alignment specs of course. I imagine
that it will handle well.

I have gotten pretty used to these alignment settings over the past 7 or
8 years, though they did do too much toe-out in front last time and I
never bothered to take it back.
Pretty fun, but it was little, (ok, a lot), darty and it ate the tires
extra-fast.
I also had to watch that steering wheel on the highway, a little bump
would put the car over almost one whole lane.

Pat

"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.

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.

*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.

Leon

>>>Less restricted airflow to the engine
>
>>
>> More restrictive airflow. If you take in cooler air, it is denser.
>> Hence for the same performance, you need to increase the intake
>> vacuum. That increases pumping losses.
>
>TO the engine, not IN the engine. The idea is, when the throttle opens
>requesting more air to add to the mixture, a properly designed intake would
>be able to provide it more efficiently than a restrictive, tortuous intake.
>That's why we change air filters, to reduce the restriction caused by dirt
>in the filters. Less restriction = more available air delivered to the
>throttle when it is needed.
>
>>> performance is
>>>enhanced. I'm not saying it's true - that's why I'm asking. But the
>>>manufacturers and many owners seem to think so.
>>
>> What manufacturers? Mazda?
>
>No, the manufacturers of the after-market intakes, and people trying to get
>more performance/power from their engines. Stock intakes nowdays are
>designed with acoustic chambers to reduce ambient noise, as well as small
>air intakes feeding rectangular filter chambers that again feed round and
>oval-shaped intake tubes, eventually feeding into a round intake at the
>throttle. It is generally accepted that these transitions from one shape to
>another with various diameter and direction changes tend to disrupt the flow
>of the air making the airflow less efficient and slowing the velocity of the
>air delivered to the throttle.
>
--
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 >,
(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.

>
> 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?

>
> *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?

--
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."

"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? 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. 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) 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? 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? 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.

In article >,
"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? 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. 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.

No, it doesn't mean "combustion will be more complete".

It means there will be more combustion, as there is more air and thus
more oxygen; provided, of course, that the sensors can recognize this
fact (which they almost certainly can), and the injectors can provide
enough fuel.

--
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."

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?

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)?

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.