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KKtrips

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haha, yeah this is choice, and i do see where you're at spence. ever enjoyed doing burnouts? same type of knobbery as hitting switches. it's called 'fun'

engine driven comp has got to be the best option, but again - cost and CBF

i still dont know where this 200psi idea is coming from.

however, 3000 psi can be reduced to 2679, 10, 56 or even 120 psi with a regulator.. theyre crazy like that. presumably you would need to build a small amount of HP gear for the system though, but its just not that tricky.

not sure how a 5gal tank is wiser than a 3gal tank with regards to space?

 

anyway, moral of the story is rookie should put 12 batts, 1 pump, and 1 switch in his car.

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Hell yes I like burnouts, a dive tank solution seems like building a car that can't do a burnout and adding some NOS or something that can let you do like 2 burnouts then you have to go to a special shop and refill it. I would rather build a car that does skids all the time, I like my car to be self sustainable so if it can do cool shit, it can do that same cool shit 3000km away from my dive tank fill up guy.

 

Yea I know about regulators but I'm sure the system needs more than one regulator to be able to pump it back up and use it as a normal tank? some kind of check valve back into the tank I guess

 

A dive tank is wayy bigger and heavier than a normal 3 gal air tank, probably bigger than a 5gal. They make them with thin walls and even from alloy and in all sorts of shapes, its quite neat, mine was like 1kg.

 

Dive tank is seriously just for hopping and being a wanker and that defeats the whole idea of bags on a old car? low when needed, then normal car everywhere else. Just get juice or a well designed bag system.

 

The 200psi was just banded around by Rookie then Tom. It hurt my feelings.

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If you want to look at fill rates etc.

http://www.viaircorp.com/480C.html#tabs-3

 

Down the bottom right is the specs, rates etc.

 

If you had a light car and a small tank the 480 can run 1.07 CFM @ 100 psi (500cc/sec) so even if you ran out of tank puff the pump is no slouch.

But 2 pumps and a bigger tank is always better, MORE IS MORE!!!!!!!

 

I'll be starting with a single 480 and a 3 gal tank. Can always add more right :D

Get your calculator out!

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If the car weighs as much as a crown (merc?) then you probably want more, that first up will trigger the compressor then you can go put the jug on while you wait for more. (wild speculation from my sample size of one car)

 

And sweet Jesus put some thought into isolating the pump, that noise. 

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Rookie here's my experience with the crown, it had a 5 gal tank and I would run it up to like 160psi, that was just enough to go up from full drop once. It had one decent sized Viair compressor and it took forever to pump up, you need minimum of 2 electric compressors and a well thought out housing for them, rubber mounted in a enclosure that has ventilation to minimize the god awful noise. Crown weighed maybe 1600-1700kg and needed like 90-100psi in the front and 40-60 in the back at ride height. One compressor and a 1 gal tank sounds like the worst thing ever, you will need to go engine driven with a tank that small.

 

 

fuck, none of those stats are the same for my car. i got a 5 gal tank and it runs at 150 psi max.  ride height is 70psi front and 30 psi rear. it'll go up and down like 7 or 8 times before the tank runs out. the compressor is pretty quiet and when your driving you can't hear it. it takes about 4 minutes to fill from dead empty but its never at that level. up and down a few times and it might run for a minute or so? 

i just looked at the ride tech website and the compressor they list now is different to my one. I'm not sure what my one is but it looks OEM for something euro. i reckon it would push higher than 150 with no issue, it doesn't slow down much in rate of climb as it gets to 150. 

car weighs 1300ish.

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It's too late and hot for this but I'll give this a jam.

 

Min to max lift of biggest bag of mine to 100 psi (lots psi, max lift)

1.6L per airbag x 4 = 6.4L

 

Lets say 100 psi all round @20 degrees (9.37g/l)

 

Tank pressure

200 psi @20C (17.54g/l)

 

17.54g - 9.37g = 8.17g / 9.37g/l = 0.87L (per 100 psi drop per litre tank volume)

 

6.4/.87 = ~7.36 L (1.94 us gallon tank would balance out bags and tank at 100 psi)

 

Or am I waaaaaaaaay off :)

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Oh shit I thought you got the 2 pump job, well either your pump is amazing or my 1cfm Viair one was the worst ever. I might have to plumb the one up I have downstairs later and do some testing. You are like the only person I know who is happy with their one pump setup.

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Dive tank just has a regulator on the top of it that knocks it back to 150psi or whatever, that goes into the main tank so you don't need 3000psi safe valves etc

 

Oh yea that's the easy part, obviously divers aren't eating 3000psi air. But the regulator will be one way right? so you need to add check valve & extra tee fitting if you want to use it as steelies suggested? (ie normal bag tank when empty) didn't say it was impossible, just seems extreme on a normally driven road car.

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Sounds like yours was a proper dog of a pump spencer :(

 

If my crude scribblings are close to correct you can imagine plugging sheepers specs into the equation. 5 gal @ 150psi gives you many grams of air (I find it a little easier to think of grams instead of volumes as what does 5 gals of 50 psi potential (above bag inflation psi) actually mean?).

 

If...... WHO asked the question again? ...... would like to put in their bag specs that'd be good if they have them worked out we can all do a little maths and perhaps get more learned.

If they don't have their specs we can work them out if they have spring rates existing or vehicle corner weights and bag height requirements. Or back to front if they have the bags they want.

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Ok car is an e30 touring, the bags will be the universal aerosport strut bags up front and universal air house 2's in the back.

The reason I have been saying 200 psi as that seems the be a common marketing number and there are hobbs switches that seem to be for sale. So my thinking was that if I could only have a 2 gallon tank then craming an extra 50 psi in it seems like a reasonable idea as long as it isn't at the detriment to other things (which according to Spence it seems like it might).

As for spring rates I honestly have no idea, I have a feeling 350 in the front and 600 in the rear?, but that could be wildly wrong. The car is currently on coil overs and is about 60mm off the ground and it is Fucken annoying hence bags, so going from aired out to full height in one go isn't really necessary, just as long as it gets it to more than 60mm then it would be sweet.

Kind of keen to know what pump you have sheepers, if you dont mind?

Also a pic of the car for inspiration.

11377837_1473029732998185_423922167_n.jp

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Dive tank is seriously just for hopping and being a wanker and that defeats the whole idea of bags on a old car? low when needed, then normal car everywhere else. Just get juice or a well designed bag system.

 

 

 

spam, but i dont consider hopping being any more of a wank than burnouts - keeping it objective here. being a wanker is the issue. rather it augments the idea of bags in an old car if you have much greater abilities and dont choose to use them. kinda like running a bigblock in a road legal car..?

 

a tee and a check valve doesn't sound that scary.

5 gal tank is 7.5"x27", 3gal scuba is 7.25"x26", so yes, bigger for its displacement, tiny by air volume, and a smidge smaller overall.

i know i cant prove my point to ya spence!  cant really beat the norm in an argument.

 

Cletus, how long did it take you to flatten the dive tank, and under what sort of use, out of interest?

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Oh yea that's the easy part, obviously divers aren't eating 3000psi air. But the regulator will be one way right? so you need to add check valve & extra tee fitting if you want to use it as steelies suggested? (ie normal bag tank when empty) didn't say it was impossible, just seems extreme on a normally driven road car.

You wouldn't want to do this, its not practical. When you decide to get the dive tank refilled at the dive shop, you need to remove it from the car. Chances are they are not going to do it on the spot when they are busy (I know this, I dive as well) so while you wait you will either need to wait for hours in their car park while they refill you tank. Or the better option, drag the ass off your car around town while you wait  8) OR you would own two tanks.

There seems to be a stigma around the dive tanks, that they are for hopping. Yes, you can get them to (kind of) hop, but you can also regulate the pressure coming out to what ever you want, in my case it will be below 200PSI so it will fill the existing 3 gal tank quicker and the compressor wont have to come on. If you fancy the hopping tho, just get hydros, they are way more fun, you can get more lift and you can three wheel! 

 

I am going to do the engine driven compressor eventually, but like others have said, the dive tank is a stop gap until then as I have all the parts and it will work in conjunction with the system I have. 

 

Do you have space in the engine bay for a couple of small tanks, it doesnt have to go in the boot. You could fab them up from alloy.

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