design flaw : F20A 's air intake gets useless heat from radiator*coolant

Page 1 of 2  
* via thermostat is [i] steel-piped next to & heat is transferred into rocker cover's breather hose www.autozone.com/images/cds/gif/medium/0900823d800cf9d1.gif
, this heated air is then sucked through PCV valve & into intake manifold.chamber [ii] rubber-hosed into bottom of throttle body www.autozone.com/images/cds/gif/large/0900823d800cf4a6.gif , & heat flows into the air passing throttle. Both designs make air intake & cylinder head unduly hot www.circletrack.com/techarticles/1822/ : whenever intake manifold heats up ( esp in long trips ), torque drops & warm-starts are difficult , both because hot air cannot expand much when heated. Ideal temperature of air to receive injectors' spray of petrol is just 40C 104F ( www.turborick.com/gsxr1127/gasoline.html para 10.2[7] ). Intake manifold where injectors spray petrol ( near cylinder head ) & chamber already get heat from manifold's contact with cylinder head, EAC & Fast Idle valves ( both heated by * ), certainly do not need more heat. If designer wanted manifold to heat up fast, then throttle body must have a thermostat to stop * inflow when throttle is heated to 40C. These 2 designs make steep hill climbing slow & weak ; * & air intake will both be @ their hottest, & torque will be lowest ( ironically, when torque is needed most ). After I disabled these 2 designs, in 28C air, [i] chamber, manifold & cylinder head are cooler, benefits are many e.g. 1 can use ( cheaper ) mineral oil & lower viscosity [ii] torque ( 5% > before ) does not drop after * heats up [iii] warm-starts are easier.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

There isn't supposed to be much air flowing through a PCV system.
Maybe the thermostat for your throttle body, if it has one, is faulty. It's supposed to keep it warm, not hot.
Maybe you fixed a symptom, not a problem? Your posting is hardly clear.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
TE Chea wrote: <snip>
you need to stop drinking the "cold air intake" coolaid there guy. it may be fine for you kidz in the nice warm county of l.a. to run about with disabled de-icing equipment, but anywhere else in the country, it becomes a bit of an issue when your car sputters to a halt because of ice buildup.
as an aside, i had my air intake cover off the other day, and forgot to screw it on tightly. the screws worked their way out after a few hundred miles, and the air intake cover popped off. it was noticeable by two things:
1. increased noise. ok, ho hum.
2. big /decrease/ in power. the "ultimate" cold air intake, i.e. no intake at all produces /less/ power???!!! yep, you better believe it.
now, it's possible that some aftermarket manufacturers of air intakes know what they're doing and understand airflow resonance dynamics and the effect it has on engine air induction, but somehow i doubt most of them do. but hey, most of this stuff is not for performance, it's just for show...
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Uh,the air intake is still from the hot under-hood air.All you did was shorten the intake runner length,which reduces torque. If you don't believe cold air enables more power,then explain why racers put scoops and ducts on their race cars.It wouldn't make sense,adding more drag to get cold air that doesn't produce more power.

--
Jim Yanik
jyanik
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim Yanik wrote:

uh, i understand how it works thanks. what i'm saying is that it's not so simple as most of the "cai" crowd believes. if the intake tubing is tuned correctly, i.e. resonances are set specifically, it enhances the air charge entering the engine. done right, it flattens/broadens power/torque curves. otherwise you're stuck with huge flat spots in the engine's performance, exactly what i was experiencing.
"tuning" the air charge has /way/ more effect than the minor density differences made by a few degrees of ambient air temperature.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

If Honda Tuning Magazine still has the article,they did flow bench and dyno tests on an RSX for several different brands of short rams and two cold air intakes.They did a reference test on the unaltered vehicle,then tested each intake system.Both CAIs got 20HP and modest torque increases.The short rams only got 5-7 HP gains. They included their graphs in the magazine article.They also discussed the effect of intake air temperature WRT making power.
It was a very informative article.Maybe you can get a back issue.
--
Jim Yanik
jyanik
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim Yanik wrote:

i appreciate what you're saying jim, but did they drop a thermistor into the air stream to measure the difference in air temperature between the two? i'll be surprised if they did because i can't say i've ever seen one of those "dyno graph" articles that ever has. without that, they're simply measuring the dynamic air charging effect differences - what i was talking about before. you're right, temperature /can/ make a difference to power yield [an 80 degree difference in air temp gets you roughly 10% difference in air density] but again, have you ever seen temperature reading differences quoted? and what difference does it make for a *moving vehicle* with & without cai? airflow under the hood is, well, you get the picture... just questions to ask.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

They used the OBDII intake air temp measurements read from the ECU's own sensors.

even with airflow under the hood,the underhood temerature is much higher than outside.There's radiated engine heat that is retained.

You really should get a copy of the article.
--
Jim Yanik
jyanik
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim Yanik wrote:

great! what were they?

you need to re-phrase that one dude. radiated heat, by definition, is not retained. and a sensor inside the manifold is not going to experience much radiated heat from anything other than the manifold itself.
i think what you mean is that air drawn form under the hood i.e. downwind of the radiator, is warmer, which is true. but in these pics
http://www.rsportscars.com/foto/03/civic-eng-broechem22000_003.jpg
http://www.rsportscars.com/foto/03/civic_si_blue_motor.jpg
http://www.clubcivic.com/gallery/files/2/3/3/4/5/DSC01335.JPG
http://www.clubcivic.com/gallery/files/2/1/3/8/2/DamdamImage384.jpg
etc.
in all these cases, the cai's are /all/ downwind of the radiator, so i don't see what the "cold air intake" is achieving in the thermal department, unless it's on a static vehicle with the hood open. and i'd love to see numbers on air temp for a /moving/ vehicle, especially as oem intakes all draw air from up front of the radiator. if all these kiddiez were serious, they'd cut through the fender and/or hood and put a real cold air scoop to the outside world, but i've never seen that on a cai'd civic.

scan it and send it to tegger.
again, i see dyno differences mostly attributable to air charge resonances, not actual air temperature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
>>

And I'd be delighted to post such results.

And what sort of changes are we talking about here? 5 BHP? Less?
--
TeGGeR

The Unofficial Honda/Acura FAQ
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload


I don't have the magazine anymore. I DO wish I'd kept it.

for CAIs(not short rams),20 HP for a RSX. IIRC,that was measured at the wheel by Honda Tuning's dyno.
--
Jim Yanik
jyanik
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Radiated heat (from the engine) gets absorbed by other things under the hood,including the underhood air.Thus,it's retained.

these are all SHORT RAMs,-not- COLD air intakes(CAI) ;BIG difference. CAIs are longer,and run down through the wheel well to draw cooler air from outside the engine compartment.(thru the original intake's passage.) that is why HT's tests showed only 5-7 HP for short rams and 20 HP for the CAIs,and torque increases for the CAIs but not the short rams. Air temp was the big difference.

No need to;there's an opening available stock;the Honda/Acura intake is quite complex,and convoluted.the resonator tank and associated plumbing is unseen,hidden in the wheelwell in front of the wheel,you have to remove the wheelwell liner just to see it.(personal experience!)

I have seen where some folks made their own ducting and air box to supply the short ram with cold air.

I don't have the magazine anymore. I haven't found it on HT's site anymore,either.

--
Jim Yanik
jyanik
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jim Yanik wrote:

dude, the engine's at 78C. that's warm to the touch, but it's nothing from a radiant heat standpoint. what you're feeling is convective heat, primarily wafting around from the [very hot] exhaust and the radiator.

they're all /sold/ as cai's:
http://www.car-stuff.com/performance/quote.php?make=1&year 00&model=1&brand23&part_name&category like every single item on that page.

respectfully, i disagree. the effect being observed is dynamic supercharging. otherwise the length of the tube would make no difference, it would be purely air temp. seriously jim, the effect of airflow dynamics are huge. you're right, a lower air temp helps, sometimes by a noticeable amount, but it's chicken feed compared to a mismatch between a given intake tube's resonance and rpm's. that's why you'll find variable-geometry intake manifold systems on a fair number of modern un-turboed cars, but air cooling only on turbos where air temps can increase significantly. and even then, intercoolers are more to help reduce detonation effects of inducing hot air than they are to increase air density.
http://en.wikipedia.org/wiki/Variable_Length_Intake_Manifold

i know about the resonator. my first civic had had it's resonator removed for some reason i never figured out. performance sucked until i replaced it.

sure. and integras take air in from under the front bumper. but that's still better than the products sold as "cai" because they have nothing to do with cold air!

well, i looked online and finding any article that mentions actual air temp readings, let alone one from a moving vehicle, takes /way/ more patience than i've got.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The following treats the rams but says the CAI modifications weren't yet available. Maybe you can improve on the search and turn up your article.
http://www.hondatuningmagazine.com/tech/0201ht_acura_rsx_type_s_aem_intake /
Of course as I'm sure you know, Jim Yanik, colder air means more dense air, which means for the same volume of air flow into an engine cylinder, more fuel may be admitted. So of course engine power can increase and substantially. (OTOH, as has been discussed here in the past, this does not necessarily translate to more overall fuel efficiency for the car. For one thing, if the air is cooler because of lower ambient temperature, then the car sees more wind resistance.) Certain industrial size diesel engines, for one, have an air cooler built into them to increase power.
Whether these seemingly popular (according to the makers who have plastered the net with their claims?) aftermarket CAI devices do anything meaningful is still not clear without more information. I see the ads claiming up to 15% more power.
I'm sure this subject is beaten to death on Usenet...
I do not see how leaving the screws loose on the air intake cover affects air intake temperature in any meaningful way, though. Maybe Beam has backed off this assertion.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
TE Chea wrote:

<SNIP> does not drop after * heats up [iii] warm-starts are easier.
--------------------------------------
I looked at your other posts. Why do you own such a badly designed car?
'Curly'
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

His post makes no sense. I read it twice and still can make neither head nor tail out of it.
--
TeGGeR

The Unofficial Honda/Acura FAQ
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
TeGGeR wrote:

they never do.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

What a laugh! I just read through some as well. I love this one: "Bonnet's rubber seals & felt, front wheels' hub caps too can be removed, to help cool engine."
Sounds like his problem is the loose nut between the steering wheel and the driver's seat.
Steve
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
| > Why do you own such a badly designed car? So far all its design flaws ( 3 more & 2 inadequacies which I tell friends & relatives ) can be corrected / mitigated. I love its 4ws ( saves time, very scarce now : no new model has 4ws ), perfect rust proofing. No electric / hybrid / toyota's super 4ws on sale yet.
| "Bonnet's rubber seals Removal of these let air enter & cool intake manifold & chamber , & let out hot air produced by air con's radiator. Torque rose 3%.
| & felt lets heat enter bonnet & escape via convection / radiation
| front wheels' hub caps too can be removed, to help cool engine. My front wheels used to be too hot to touch, caused by this * flow design flaw & cheapo exhaust manifold. Removal of hub cap will let drive shaft & engine cool faster, unnecessary for well cooled engines, but for desparate users with severe overheating, this can help a bit, esp on original steel wheels with 15" plastic caps.
| loose nut between the steering wheel and the driver's seat. Salesmen / dealers all deny flaws, & denigrate to deter exposers, to protect their bread & butter, just like in 1 thread above ( 11-5-06 ) on ignition switch.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You've got to be f***in kidding me.
Plonk.
Steve
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.