The Bush-mechanic "CAI" partition

[zanda]

Ok,

following a number or resounding endorsements from team members on this forum, I tracked down Jay95s CAI partition template from this thread, and, with a few minor modifications, constructed what can only be termed a "rough" example of a cai partition.

[zanda]

Note that I have incporpotated a feed from the standard airbox feed. this is in addition to the air which will naturally flow past the headlights and the front grill/bar.

I have also incorporated a lid, which should perform roughly the same job as sealing a "walled" partition against the underside of the bonnet.

[rb25]

nice job zanda. mines just a piece of heat shield and is a bit rough too but hey, if it works its fine!

[zanda]

Like many other people - in fact surprisingly more than I originally thought, judging from the recent SST SAUWA dyno-day - I elected to use a fairly thin "bunnings-spec" 2mm thick aluminium sheeting to construct the box.

this is shown nicely in the photo of the inside of the box.

note the flimsyness of the lid and the quality of the construction.

[Champinco]

just out of curiosity, why did u partion ur air filter? and wat does cai stand for. and last one....my sectioning this part of increase performance of ur vehicle, or was it done just for legality reasoning. ie: aren't those filters illegal?

[zanda]

Enter the engineer in me.

I figure the box is flowing some nice cool air, but - after a few decent "daily-drives", the box becomes HOT.

as in - show ya mates ya "noice new box"....

"...whooaa!! its hot dude! Yay! Heat soak!! :bahaha: "

Fuelled by a burning desire to justify the entire day of hungover-finger slicing construction (at the infamous garage malaga), I decided to investigate further.

I purchased an updated version of this thermometer from Jaycar, which can take a reading from a remote sensor, which I installed in the box..

the sensor itself is held onto the bodywork, directly in-front of the pod-screw. According to basic fluid dynamics, this is where the greatest flow should be from.

note that the sensor is stuck on the metal of the body using double-sided tape, ahich should insulate the sensor from the actual metal. This was performed in order to try and measure as accurately as possible the temperature of the inlet air, prior to reaching the AFM. The sensor does not directly contact metal, and should therefore be free from conductive type heat transfer from either the bodywork or the box itself.

[zanda]

I found that, whilst the car was moving, the general flow through my box was quite impressive. generally, the temperature inside the box was around the same , if not lower than ambient air temps..

......HOWEVER!

there is a marked increase in the AIR temperature inside the box, resulting from heat soak through the partition and the lid, whenever the vehicle is stopped/moving slowly. this occurs after only a few minutes, such as when the turbo-timer is running

.......or when you sit at the lights!

[zanda]

Tempurature in the partition is on the right - duh! number in the middle is the "ambient air" temperature.

Note that I have seen this climb as high as mid 50-something degrees sitting at a crap set of lights on orrong/welshpool road, that take forever to change.

whilst I expect that such a temperature increase is more than likely experienced when there is no partition at all.....there is unfortunately still some more bad news.

the fact that the partition heats up soo much, means that there is now a radiative and conductive heat source placed CLOSER to the pod itself. subsequently, the air inside the box takes much longer to cool down than if air could flow freely through the intake without passing over a hot-ass partition!

(note again that the above temp reading should be inlet air temp, not partition metal-sheet temp, which I would expect to be significantly higher)

this is what happenned after about 5 minutes of driving (80-100 km/h) along the freeway from mywork, where the first pic was taken, to the exit near my house.

[zanda]

conclusion: the bushman-airbox (or bush-bitch-box) in it's current form is actually robbing take-off power under city driving conditions.

At night-time, or with a good run of lights, the partition does work quite effectively, and does stop hot air from the engine/turbo/intercooler piping getting sucked directly into the box.

[zanda]

well,

in true d.i.y.-er spirit, I refuse to be disheartened by my shitty end product.

I have purchased some special shiny heat-foam insulation-foil stuff from clark rubber and intend to put this on the box.

the hypothesis is that this should reduce the heatsoak and make the partition function like a little-champion. It will also hopefully improve the aestetics of the bush-box, which quite franlkly, looks....well, bush mechanic-y

at the same time, I also hope to do a comparison between bush-box and no-box, which I can then compare to plush-box.

will post photos results soon, pending dry day and digital camera access.

[caminperth]

Eagerly awaiting the next installment..

Tell me - are you planning a catbashin segment? I hear that can be a cheap and effective way of increasing power?

[Pva_Glue]

thank you zanda! that was great read

very effective I see... keep up the good work

[Jay95R33]

Lining the inside of the box with the heat resistant foam will help fend off heatsoak.

I used the foam and there is a noticable difference in temps using the 'hand method' !!

J

[rb25]

zanda - i find the heatshield stuff to work very well. my 33 feels heaps more powerful off the line.....

Jay95R33 - i've only used the 'hand method' but im sure the heatshield is better than a metal box.

Boxhead's R32 (with FMIC) has a metal box with the heatshield inside and the box still gets really hot. i cant even touch the plenum or the x-over pipe on his 32 coz its too hot. whereas my plenum is 'warm'. certainly not hot...

[predator]

do b4 and after temps and stuff.. very curious myself.. i'm buying one of those temp meters myself to get down all my temps I think.

I have your standard "plastic pipe where old stock i/c pipe is feeding my pod, which is partitioned with heat resistant foam making its own partition with the bonnet insulation"

Would be an interesting compare, but i need a temp metre to measure mine first. At the moment i have the stock box back on, but pod will be back on soon.

[51jay]

My Cold box is made from approx 1'thick soft foam with aluminiumised layer on both sides, I've just got the thermometer so it will be interesting to see if it resists heatsoak at idle any better.

[zanda]

Yeah, will do Predator.

I think the insulation stuff I have is the same as 51jay, but with the shiny aluminium coating on one side only. This will go on the outside of the box in at least one layer.

that thermometer is choice. it also has a battery voltage reading and glows with an el-light for extra rice-effectiveness.

boh!

[51jay]

It is similar but my stuff comes from an insulation specialist at $49 a metre. It's aluminiumised one side and self adhesive the other, it's actually 10mm thick so my box is 20mm thick 2 layers, not 1'.

As zanda has seen just about any box material will work when the car is moving, the thing is how long will it resist heat soak eg when you'r hanging around the staging lanes.

[Grim]

my CAI partition is made from a $50 piece of 3cm thick high-grade neoprene insulating material (the stuff wetsuits are made of).

Here's how I went about doing it: http://www.performance-mod.com/nuke/html/m...ews&new_topic=2

[Guest Boxhead]

yes, as ross stated my pod filter box used to get quite warm from engine temps. however it does have the foam insulation on the inside...

now, on creating a huge 100mm cold air intake from were the stock intercooler comes from, i can now say that the heat of the outside of the box is decreased immensley, its now luke warm if that...