Need to find/make a box capable of holding air pressure...

[V]

I need to obtain or fabricate an Al or steel box, it needs to be about 6"x6"x4" size(I can work with sizing), drillable sides(at least on tappable), and withstand at least 50psi internal pressure high, with a sustained around 32psi.

Is this even possible, better yet safe? Lol.
It would be trunk mounted.

Don't even try to speculate what its for, you'd be wrong.

[LTb1ow]

Any reason it has to be square?

If you just need the volume, it may be safer and easier to stack a few tubes of 4inch SCH40 PVC pipe tied together. Rated at 100psi, it would be lighter and safer.

[V]

tubes could definitely work. I wasnt sure or the PSI rating. Do they come in a say 3" diameter, even though 4 would work. and i assume id just use end caps to seal them off? but would the ends hold the pressure too?

point of the square-ness is for neater packaging. Could always put the pipes in a plastic housing. hmmm

[LTb1ow]

Yea if you get SCH40 or 80, they are rated at 100psi, and with the proper prep and glue, the end caps will hold no prob.

I used it all the time to make air cannons etc.. you can get 3 and 4 inch stuff all over, but if you go to lowes/home depot, make sure you do NOT get the DVW stuff, its thinner and will not hold pressure.

[V]

ok, ill def have to look into that. once my idea is complete, ill post up about it.

its something im trying to make to sell eventually, and im thinking cost wise. As of now im already looking at 100-150 for main components, then 10-20 for secondary components, and final cost would be the container. Im trying to stay under 225 total and this may work now...

[LTb1ow]

Is this for a air ride suspension?

What kind of volume does it need to be able to flow at once?

[V]

it wont flow anything. lol. ill PM you.

[LTb1ow]

PM'd ya back.

[WildBillyT]

TIG one out of aluminum, then put bungs on it for your pressure fittings. You can probably get a radiator place to do it, and if you get the fittings put in you can have them pressure test it. Or mod something like this:
http://www.ecklers.com/corvette-expansion-tank-with-small-block-1968-1972.html

You may already have one of those- you still have your Vette, right?

Based on these pressures, sounds like an oil application :D

[Pampered-Z]

Would a hand held propane torch tank work? they are about 4"x10" or the mini-grills use tanks about 6"x8". They are probably built stong eough for the pressure you want, if you need more you could probably cut the ends off and weld two together? Can you adapt the propane fitting for what you need?

[V]

main issue is i need to insert an object into this container prior to closing it up. cant really do that with a propane tank. cuz most welders aren't skilled enough to make something air tight.

the PVC pipe idea will def work. and it would be a one time fill type of thing, and only add air if need be once every few months, so no fitting connections are needed.

[smoke_em94]

is this for ur tire pressure sencors lol

[V]

is this for ur tire pressure sencors lol

yup lol

[smoke_em94]

a buddy of mine used two pvc caps and put a vavle stem out the one end for his vet

[BonzoHansen]

why are you doing this?

[smoke_em94]

to be able to run lower tire pressure at the track

[WildBillyT]

to be able to run lower tire pressure at the track

Why not get a 12V air compressor, or mount a compressed air tank?

[BonzoHansen]

why, does the car go limp is the tpms trips?

[Stevoone]

If your planing to use the original sensors it may not work. The sensors work by centrifugal force. Under 20 MPH the sensors are in stationary mode and will only transmit once every 60 minutes, over 20 MPH they go into drive mode and transmit every 60 seconds. If the computer does not see the sensors go into drive mode your going to set the TPM light.

[V]

why, does the car go limp is the tpms trips?
correct, stabilitrac will not shut off nor will competative mode engage

If your planing to use the original sensors it may not work. The sensors work by centrifugal force. Under 20 MPH the sensors are in stationary mode and will only transmit once every 60 minutes, over 20 MPH they go into drive mode and transmit every 60 seconds. If the computer does not see the sensors go into drive mode your going to set the TPM light.
this is the issue im currently looking into

edit: do you have any specific info on this exact setup and what the ecu requires to see etc.?

[Stevoone]

You could do something with a magnet, that would hold them in drive mode.

[BonzoHansen]

correct, stabilitrac will not shut off nor will competative mode engage
can you tune that out?

[V]

can you tune that out?

doubt it, i think its in the BCM, hp only gets me into the ecm.

ill look into it.


i wonder if i could find out how to capture the RF id code, and try to clone it into a chip based electronic device that would be programmable... hmmm. time to talk to my tech buddies.

[Anti_Rice_Guy]

can you tune that out?

Not that I know of easily, because I tried to do that with my Exploder since my summer wheels/tires don't have sensors and I check my tire pressure once every 2 weeks anyway.

[V]

i was pondering... if i can open up the sensors and bypass the inertia circuit with a relay perhaps(from what i read they just "sleep" until movement), it would activate the sensors as soon as you turn on the ignition, and the self contained batteries would hold the info so it wouldn't have to be rest each time. Then car off, would allow them to sleep once again.

[Whiplash Performance]

http://www.m3post.com/forums/showthread.php?t=298574

That guy already made one for a BMW.

[V]

http://www.m3post.com/forums/showthread.php?t=298574

That guy already made one for a BMW.


exactly what im going for, but for Cadillacs. hmm

[creeper]

what about just having your spare tire remounted with the sensors inside? fill it to whatever psi you need, and just mount it in the stock location

might weigh a little more than a box but it wouldn't be as weird looking hahah

[V]

what about just having your spare tire remounted with the sensors inside? fill it to whatever psi you need, and just mount it in the stock location


the system works off reading each sensor by position which you need to program. kinda hard to program them when they are inside a tire. i probably wont have to relearn them if i use my original sensors, but i still face the issue of the inertia circuit when moving, and then makes the spare useless, and as it is, most V's dont even carry a spare since stock they never came with one. (and a base cts spare wont bolt onto the V) I have an oem rim/tire i bought from another V as my spare which barely fits in the trunk well. so overall that idea isnt very feasible.

these cars have been around for over 6 years now and no one has effectively tackled this issue. I will.

[BigAls87Z28]

I did not know that the TPMS played with stability control?!?! Wow...

[V]

I did not know that the TPMS played with stability control?!?! Wow...


yup. And i went through the diagrams, seems There's a radio antenna module that picks up the TMP sensor signals which then feeds a rear integration module, from there forward, all connections are through serial data, no way to intercept the TPMS signal. HPtuners obviously cant touch it since its in the BCM apparently, so no luck there.

Im trying to find the frequency of the RF signal that the sensors produce and ill looking into recreating that signal artificially, which seems to be very complicated. So other idea is opening a stock sensor and integrating my own inertia circuit(ive already sourced switches). then locating that sensor(all 4 actually) in a contained pressure vessel... thats what im working on now...

[sweetbmxrider]

can you stick two monitors per front wheel or are the receivers above each wheel well? can you somehow rig the rear system to the front then?

edit: looks like it uses the rear window antenna for the receiver. i doubt it actually knows the position of the sensor so as long as they are all in a learned position, i don't see why you couldn't secure a sensor inside of each front wheel. just gotta do it with some damn good glue :wink:

that or somehow creating a false atmosphere around the sensor in the rear wheels. something like a baloon or even a small box like you were saying that had the correct pressure. just gotta figure a way of filling that or the tire. drill a new valve?

[V]

all sensors go to the antenna by the rear window, to learn them you go through a procedure and release some air out of each tire in a certain order and thats how the car knows each location, so it basically needs to see all 4 or its a no go.

[sweetbmxrider]

yeah i edited. so long as the sensors are already learned, i don't see why you couldn't secure them inside the front wheels.

[V]

that is an idea, but once again, not feasible just for everytime you wanna go to the track.

my goal is something you can almost switch on when you like with the ability to revert to stock setup with a quick relearn.

[BigAls87Z28]

This reminds me that recently, someone hacked into the signal that the TPMS broadcasts in, and started playing with the DIC. I believe it was some sort of college kids that did it for a class.

[V]

This reminds me that recently, someone hacked into the signal that the TPMS broadcasts in, and started playing with the DIC. I believe it was some sort of college kids that did it for a class.

if theres any possibility you remember who/where it was, lemme know and ill try to contact them.


edit: nevermind just found out it was Rutgers and also U of south Carolina groups.

i highly doubt theyll give out the info i need, dam it.

they used a laptop, free software, programmable radio transmitter, and a "specialized circuit".


edit #2: nevermind, i have just saved a copy of their full paper/report on the topic..... i love the internet.

[r0nin89]

As far as the box goes its not hard for a decent welder to make a vessel that will hold pressure. 32psi is nothing.

As for tapping it your going to need to have bungs welded into. The material specs to hold 32psi are simply to thin to tap.