thoughts on standard airbox

[CMF_matt.d]

been doing some reading on cold air intakes and having just taken off a ram air induction off me 1.3 and fitting standard box back on i found no difference whatsoever on performance or except it sounded the bollocks and made me car drink more!
Well im definately wanting to keep the fuel economy on me car or improve well this is my question how would i achieve this everyones input would be greatfully recieved and can it be done MORE fuel effiency.

 

[CMF_frank2]

how about some big holes in the lid, but with thick poythene over them matt ?
so the induction roar would get through but not the hot enginebay air

 

[CMF_matt.d]

frank im not after the induction roar im aiming to see if better fuel economy can be acheived better than with the standard air box been playing with airfilters etc and doing alot of reading about air intakes saying the colder the into the combustion chamber the better the effiency etc etc and would removing the waxstat seriously reduce the heat around the throttle body by diconnecting the plumbing

 

[CMF_frank2]

hypermilers use hot air intake eh matt, and using a 2nd coolant temp sensor cuts down the coldstart enrichment by about 2/3rds (mine is closed looping within 1/2 a mile on a cold morning)

 

[CMF_matt.d]

i thought hot air intake was crap for engines the motor becomes fuel inefficient thats why car companies strive for better cold air intakes

 

[CMF_matt.d]

what set up do you have frank and is it proven to work

 

[CMF_frank2]

CAI gives more power yeh, but WAI reduces the pumping losses @ very light throttle openings

 

[CMF_frank2]

matt.d WROTE:

"what set up do you have frank and is it proven to work

i,m boostin (apparently more efficient that N/A)

 

[CMF_matt.d]

you got me now frank mate please explain wai reduces pumping losses that aint good but does cai gives more power and improve economy yes

 

[CMF_frank2]

matt.d WROTE:

"you got me now frank mate please explain wai reduces pumping losses that aint good but does cai gives more power and improve economy yes

nah, when a petrol engine is cruising @ light throttle, there is about 3/4 bar of vacuum in the inlet tract (so the 9.5:1 c/r you should have is actually far less),
so the pumping losses are high and the efficiency of the engine is poor,
a WAI has less dense air, which needs less fuel, but needs more thottle, which raises the C/R and efficiency

 

[CMF_Greo]

Ebb on the uk micra forum did a heap of testing (then dissappeared haha)

Here are a few links, he was chasing power though.
http://www.micra.org.uk/threads/ebbdude-s-micro-micra-project.40020/

http://www.micra.org.uk/threads/maxi-micra-project-by-ebbdude.40439/

There are a few hypermiling sites that would have a heap of tips too

I feel the standard box with an increased intake pipe diameter would be a good option

 

[CMF_Mike R]

I drilled some 10mm holes in the end of the closed end pipe that runs into the air box from by the battery , this allowed the engine to use the pipe to suck in some extra warmed air from the engine as well as cold air from the other pipe . by drilling the 2 holes slightly away from the closed end of the pipe it still allowed the pipe to be used for "tuning" at high revs . seems to work ok , i did start with 4 holes but covered up 2 closest to the closed end .

 

[CMF_oldboy40s]

hi mike,

do you have any picts of where you drilled the holes??

cheers

 

[CMF_matt.d]

jesus i had me 1.3 micra for a couple of months now and im well and truly hooked with the information on this and the uk website out of all the cars i have owned and the forums i have joined through owning the cars this forum is the bollocks.

 

[CMF_Mike R]

here you are , I think the holes could be bigger , but trial and error suggested taping up the 2 holes at the end .

 

[CMF_matt.d]

have you noticed any change in economy performance etc or is it just the placebo effect mate

 

[CMF_frank2]

you could alter your inlet cam timing, for late closing like the dig-s K13 engine matt (miller/atkinson cycle effect)

 

[CMF_oldboy40s]

Thanks for the pict Mike.

 

[CMF_matt.d]

what does drilling the holes achieve and is there any noticable difference

 

[CMF_Mike R]

seems a bit better at lower revs , but the two taped up holes seemed to adversely affect things at higher revs ..... I thought it strange that a large pipe on the airbox should branch off into smaller pipes and the holes in the closed pipe would help improve the airflow !!
Also made the assumption afterwards that the closed pipe would "resonate" somehow and the closed end would be the "zero" point on any standing wave so the holes should not be right at the end , hence the taping up ...

 

[CMF_matt.d]

i think the second closed pipe acts like a cold air trap i havent a clue either why 2 pipes branch off the air box obviously its for something can anyone shed any light as to the design of the air box

 

[CMF_frank2]

its a helmholtz resonator aint it ?

 

[CMF_Mike R]

to steady/smooth the air flow into the TB ? ??? so everything works better .

 

[CMF_frank2]

Mike R WROTE:

"to steady/smooth the air flow into the TB ? ??? so everything works better .

noise reduction i guess

 

[CMF_1275]

I removed the mesh and put this inside the standard airbox, it made it much smoother at low revs and still does about 47 mpg.

 

[CMF_ducker]

Where u get that from mate

 

[CMF_1275]

ducker WROTE:

"Where u get that from mate

ebay http://www.ebay.co.uk/itm/290667724...AX:IT&_trksid=p3984.m1423.l2649#ht_1066wt_862

 

[CMF_matt.d]

ok thanks for that

 

[CMF_wehey]

1275 WROTE:

"ducker WROTE:

"Where u get that from mate "</div>

ebay <a href="http://www.ebay.co.uk/itm/290667724...T&amp;_trksid=p3984.m1423.l2649#ht_1066wt_862" title="http://www.ebay.co.uk/itm/290667724...T&amp;_trksid=p3984.m1423.l2649#ht_1066wt_862" target="_blank">http://www.ebay.co.uk/itm/290667724...T&amp;_trksid=p3984.m1423.l2649#ht_1066wt_862</a>

Any idea what dia i would need?
Thanks

 

[CMF_frank2]

bear in mind you will change the airflow concentration around the hotwire sensors tho (altering the calibration) especially @wot

 

[CMF_1275]

wehey WROTE:

"1275 WROTE:

"ducker WROTE:

"Where u get that from mate "</div>

ebay <a href="http://www.ebay.co.uk/itm/290667724...T&amp;_trksid=p3984.m1423.l2649#ht_1066wt_862" title="http://www.ebay.co.uk/itm/290667724...T&amp;_trksid=p3984.m1423.l2649#ht_1066wt_862" target="_blank"></a><a href="http://www.ebay.co.uk/itm/290667724565?var=590055275186&amp;" title="http://www.ebay.co.uk/itm/290667724565?var=590055275186&amp;" target="_blank">http://www.ebay.co.uk/itm/290667724565?var=590055275186&amp;</a>;ssPageName=STRK:MEWAX:IT&amp;_trksid=p3984.m1423.l2649#ht_1066wt_862

"</div>

Any idea what dia i would need?

Thanks

The one in the link, 63 mm.

 

[CMF_matt.d]

i know i keep going on about the air box but the other day i had to replace the dizzy on a mark 1 micra and found that the air box was a larger diameter box on top of the throttle body and also where the expansion tank is on mine! the mark 1 had another air box in its place above the air intake so im going to go replace mine with a donor mark 1 and let you know if i notice any difference mpg i reckon i will

 

[CMF_matt.d]

changed airbox from a 93 auto air box this box has no less than 2 air traps 1 on the end of the pipes and 1 on the air box lid since changing i have more low down grunt and it feels alot more perkier especially motorway cruising i wonder why nissan changed the original design when this box works really well.