Homemade PVC Vacuum Reservoir (Now with Photos!)
 

Yesterday, I built a PVC vacuum reservoir to increase my engine-off braking ability.

I used about a 2ft length of 3" diameter PVC pipe, 2 pipe caps, and a threaded hose barb to connect the reservoir to the brake booster.

I drilled a 3/8" hole in the end of one of the pipe caps, threaded the brass hose barb in, then cleaned out the inside of the pipe and glued it up with PVC cement.

I then cut the vacuum hose coming off the brake booster (on the booster-side of the one-way check valve), inserted a T, and connected the reservoir with 1/4" vacuum hose and hose clamps.

I took it out for a test drive and went from 3-4 presses on the brake pedal to 6-8! So I've basically doubled my safety margin! Yippie!

Currently, the reservoir is held in place with liberal use of zip ties. I'll probably whip up something a bit more permanent in the coming days or weeks.

PVC melts so obviously don't put one of these next to the exhaust manifold or you'll find yourself suddenly without brakes!

millenniumtree -

Eeeeeen-tay-rest-ink, :) . Can you post some pictures?

Thanks,

CarloSW2

Very clever! I'm going to add this as a 'planned mod' to my Vibe.
I agree with cfg83; we need pictures!

Definitly need pictures. :) Sounds like a nice cheap mod.

Very cheap. About 15 bucks. I tested it again this morning, and got 6 full presses on the brake, and one more that was effective but not as powerful as the first 6.

I see it as just an added margin of safety, because I practically never press the brake that many times. On a big hill where I didn't want to grav to 60mph though, it might pay off. :D

Oh, I'll have pictures this evening. I'll try to remember to take some when I get home. It's really pretty much exactly what you'd expect though. A PVC pipe, capped on both ends, zip-tied under the hood with a hose connecting it to the brake booster hose. :P

Hmmm, but does it have any effect on the FIRST brake press after the engine starts? In other words, does it take time to evacuate the resevoir to give you boost? So if you have to panic stop just a few seconds after starting off (for example you start through an intersection just as some nut decides to run the light), do you have brake boost?

Very cool idea I was thinking the other day about this but couldn't figure out something cheap. Great Idea on pvc. I have some of that in garage.

I was talking about EXACTLY this same thing yesterday!

The discussion started, talking about a PVC tube cannister for vacuum for an electric vehicle, and then moved on to talking about doing this for an ICE (internal combustion engine) vehicle for better braking on extended Engine-Off-Coasting.

Good Job! (I second the "post some pictures"!)

instarx, I seriously doubt it has any noticable effect. The return of brake boost feels pretty instantaneous when the engine restarts and this seems to have doubled the capacity, so it is 2 x Instantaneous.

Yes, double the engine-off braking capacity, and no, there is no noticeable difference in braking effort or effect. I've took some decent stabs at the brake pedal for testing purposes, and there seems to be no difference in braking ability. It'll still lock up the tires quite readily.

Here come the pictures!!

Parts needed: 3" PVC Pipe, 2 pipe caps, 1 threaded hose barb (brass)
http://millenniumtree.com/vacuum_reservoir/img_2245.jpg

Connection to vacuum line To the left is the check valve that prevents vacuum escaping when the engine is turned off. Then the T connector (3/8", 1/4", 3/8"). Use properly sized hose clamps and make sure there are no leaks. I'm going to replace the T with a brass unit when I next get to the hardware store. The plastic bit from the auto parts store is just too flimsy.
http://millenniumtree.com/vacuum_res...072108_001.jpg

This thing is pretty big. It's zip-tied in place for now but I'd like to add some beefier pipe strapping that's screwed into place. It holds well right now, but it could be better.
http://millenniumtree.com/vacuum_res...072108_002.jpg

The hose barb connection on the reservoir. I just drilled a hole in the end of the cap and threaded the hose barb in. (It's a 3/8" ID pipe thread used for water lines) If you drill the hole JUST big enough for the threads to get started, the brass pipe thread should cut its own threads into the PVC and make an air-tight seal. I'm sure I don't have to tell you, but make sure the inside of the pipe is CLEAN. Anything left inside here could potentially get sucked into the engine, or plug up the valve, causing your brake vacuum to leak out when you shut the engine off.
http://millenniumtree.com/vacuum_res...072108_003.jpg

The car. Bone-stock base-model 1.5L 16-valve.
http://millenniumtree.com/vacuum_res...072108_006.jpg

Blatant self-promotion. (53mpg is the average of my last two tanks)
http://millenniumtree.com/vacuum_res...072108_008.jpg

millenniumtree -

Cool, I like the 53 MPG too. Go 4th Gen Civic Hatch, Go!!!!!!!!!!!!!!

CarloSW2

Excellent idea. When the vacumn is used up with the engine off, how long does it take to come back after you turn on the engine. Is the delay even noticeable?

ollie

Summit SUM-G1464 - Summit Vacuum Reservoirs - summitracing.com

I used to run these on a 455 pontiac motor with a 505 cam in it. Same theory only this is made of steel.

It might be interesting to install a vacuum gauge on your dashboard, so you always know exactly how much you have.

Holy crap, I was just starting to draw up kinda the same thing! We do a lot of work on low-vacuum cars and braking systems here at work and I noticed if I was on the highway during stop and go long decel situations I might run out 1/4 to stop because of all the changes in everyones driving speed. I like it!

I like bennelson's idea of a vacuum gauge. We have tons of these at work.

Awesome work and great pics.
Dangit now I have another thing to do. Eoc Switch and this will be going in at the same time.

I don't even notice, but I'm not hitting the brakes as soon as the engine fires up either... I may give it a try, but I'm pretty sure the delay is insignificant.

In order to test it, I'd have to run the brakes completely down (8 presses, at which point I'd most likely be stopped), then fire the engine up and try to brake again immediately.

Another great idea what do you guys eat for breakfast. Like a fuel gauge for your EOC brakes I likey.

I'd like to get a vacuum gauge anyway to help me drive efficiently, but having a second one for the brake booster would be pretty groovy too.

I think a vacuum gauge will be my next mod. Maybe I can mount a switching valve inline so I can check both levels with the same gauge. I searched for a dual-needle gauge online, but was unable to find one.

Can you get an electronically controlled air-switching valve? Then you could have it read engine vacuum while the engine is running and brake vacuum when it's off!

Hrmmmmmm... Got me thinking now!

You could switch it electronically if you had 2 electronic vacuum sensors and an electronic gauge... Then there'd be no vacuum loss/leakover when you switched the valve...

(after a bit more searching) OMG forget that. Electronic pressure/vacuum transducers are about 10 times the price of a gauge.

This is a really good mod! Props.

Love the window sign too.

Hi, please help. I can't see the pictures.. thanks.

Sorry, I changed my site structure a bit.
They're back up, and thanks for letting me know!!

i was thinking why not check your vacuum gauge to see if you can get good braking at half engine vacuum pressure cause if you can get a pressure reducer for your vacuum tank thats at half your engines vacuum pressure then you just doubled your number of braking again??

Hmm seems that heat "may cause" wrinkles.
I think my under the hood temps may be a tad high, that or the location next to the cat on my vx might not be so good.
It did last since 2011, time to replace and relocate.http://ecomodder.com/forum/emgarage-...cb8b95d8fb.jpg

Just spend the $40 and get a unit that is designed for the job...

http://www.summitracing.com/parts/sum-g1464/overview/

the original specs of 2ft by 3in comes out to 170 cubic inches(2.8 liters).

going off of external dimensions of the one from summit, that's 133ci(2.2 liters).



draw whatever conclusions that you would like from that.

Wow. I guess you're alright, which is good. FWIW, mine is on the passenger side, toward the engine compartment, between the battery and the intake manifold, above the transmission. It has been there maybe 6 or 8 months without problems. The CAT is probably 900 degrees sometimes, I guess. That's gotta be the issue. I have my build process in my modding thread if you are curious. (See link below.)

EDIT: http://ecomodder.com/forum/showthrea...tml#post412414

It's about 175ci

Cheers, james