Home Made Boost Controller Issues

[Idiot Stick]

ok, me and a friend of mine were bored the other day so we threw one togther, i wus quite happy with how it looked, took a little brass elbow basically, tap and died a screw in the top, with hose barbs at the end, and a spring with a little bb type of deal for the ball bearing, now i'm positive everything is hooked up right and capped off right. i'm not leaking any boost at all! BUT, i'm still at 10psi? now i'm thinking the little bb (which is bigger than a BB gun bb) is to small or my spring isn't right, we tested and tested and coudn't get over 10 psi, we finally took the spring and bb out, and sure enough, still 10 psi. So would this mean the we need a bigger spring/bearing combo?

 

[Captain Morgan]

do you have the correct lines going to the correct places? i had my line from the BOV switched around with the wastegate line and i could only get 11 psi...might recheck that

 

[nine5raptor]

sounds like your spring might be too light. if it can't hold even 10 psi screwed all the way in, then you need a bigger one. I went through about 12 dif. springs and still don't have one that gives me exactly the adjustability I want, but works. also make sure your bb seals tight. You can take the mbc off and suck on the boost side and see if it leaks. If it does leak, take a dowel and hammer to it to seat the hard bearing in the soft brass.
just keep experimenting and good luck...just don't blow the engine from overboosting.

 

[nine5raptor]

Where in kc are you? mo/ks are you part of kcdsm?

 

[Idiot Stick]

ok, well i've switched the lines around many times so i know that's not the prob, everything is hooked up fine. I'm sure the spring is the problem, i'll try to find a stiffer one, and i know the bb prolly isn't sealing like it should. There are no leaks actually from any of my connectiosn. Oh, and I live in Overland Park, i'm supposed to be on the mailing list but i haven't joined yet cuz i don't have any pics of my car. guess i'll keep tinkering with this or just spend 50 bucks and be done with it, .

 

[Black95GSX]

Ummm.... did you drill a little hole in one of the barbs to act as a vent?

All manual boost controllers have a little pinhole in them to vent pressure to trick the wastegate into opening later.

 

[Idiot Stick]

ya know, i kind of remember reading that, but i didn't take it seariously. i haven't done that yet.

 

[Black95GSX]

Do it, that's part of your problem.....

How that kind of boost controller works is by forcing a restriction by blocking flow (ball!)...... well in order to work properly and to fully manipulate the pressure signal the wastegate sees, it has to VENT pressure... it can only do that if you drill a tiny hole into the manual boost controller... which manipulates the pressure signal enough to trick the wastegate into opening later, which allows you to acheive higher boost.


Now you want to drill the hole on the hex part of the barbed fitting that goes to the wastegate, so that you are venting in the correct spot.

 

[Idiot Stick]

see, i can remember seeing that but i didn't think of it at the time, now i understand that a bit better, i imagine i'll keep messing with it untill i buy one, , but thanks fella's and i'll keep ya posted, oh and one other thing, me and a friend had a discussion over wut hose should be hooked up to the part of the elbow with the ball, he said it should be on the hose hooked up to the waste gate, i dissagree.

 

[nine5raptor]

The vent hole is to actaully prevent unnecessary lag. When the mbc opens, pressure is equalized on either side of the mbc and the pressure pushes the wg open. since the pressure differential across the controller is 0, the springs closes the valve and the pressure is 'trapped' on the wg side. if it has no where to go, it will keep the wg open and you will have one helluva hard time building boost again. the hole allows the pressure to bleed out and the wastegate to close.

the positive pressure side should push the bb away from the hole it seals against, the air will then go through the spring and on its way to the wg...this is how it needs to be hooked up.

 

[Captain Morgan]

Im in Salina, im in the the KansasDSM club, www.kansasdsm.com this seems to be the all kansas thread haha.

 

[CH152]

Salina Kansas, ive been there, stayed in the KOA on my way to go mountain biking out in Crested Butte, CO last summer. The denny's is right down the road from there on the same street. I could go for denny's right now. Anyhow i am getting off subject here but yeah the pin hole is on there for a reason as explained up there.