Jump to content
SAU Community

Recommended Posts

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.

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.

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.

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!

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.

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.

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.

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...

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.

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!

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.

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...

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...