Homemade MBC

[LAZPNO]

Ok, today i made two MBC's and tried them both out... i nearly crapped my pants when i saw the gauge... first time around 1st: 17 psi, 2nd: 18 psi, 3rd: boosted over 20 so i let way off. well, i repeatedly tried over and over, chopping the spring down each time, i still got nothing around where i wanted it. If anyone has made a homemade mbc before please post on what type of spring you used. Another 5-10 dollars and i could have boughten a freakin Joe P.

P.S. my car has been idling weird, it'll go from 1000-1500 and repeatedly rev in this area, like rev up to 1500, then drop to 1000, then rev up, repeat. Anyone ever had this problem or know what the hell is going on?

 

[90GSX]

Originally posted by LAZPNO

P.S. my car has been idling weird, it'll go from 1000-1500 and repeatedly rev in this area, like rev up to 1500, then drop to 1000, then rev up, repeat. Anyone ever had this problem or know what the hell is going on?

Wow! a DSM with Idle surge... theres lots of posts in the dsm.org archives about possible fixes to this problem.

 

[LAZPNO]

well, the reason why i ask, knowing about how dsm's have idle surge problems. This problem just started a couple days ago.

 

[IPT]

When you cut the spring you increased the stiffness of the spring. That is why the boost kept going up. You need to get a spring that is around 3-5 lbs/inch of pressure. I think that is what I have used in the past. Did you do a dual ball spring design??

 

[LAZPNO]

No, i didn't do a dual ball bearing, the screw that i used and the size of the "t" that i used didn't have enough room for the spring to be able to play. Anywayz, i figured it all out and now it works so it's all good, 14-15 psi... oh man.

 

[Todd95TSi]

Sorry to bring back a thread from the dead, but better than starting a new one......

I built a homemade one too, I have not installed it yet(waiting for 1g bov), but I was wondering which is better dual ball or single?

I have dual ball right now, but can very easily take the second one out.

Which is better, dual or single?

 

[DeezNutsForYou]

How is a ball and spring MBC better than a (fish tank) bleeder style. My bleeder works great for me.

 

[DeezNutsForYou]

can anyone answer my question, what is the difference in the two.
thanks

 

[hostile]

I bleeder works on a constant flow of pressure to keep the wastegate open. The spring type uses a spring to hold pressure off until the point where the pressure overcomes the force of the spring and allows air to reach the wastgate and open it up ONLY when you reach full boost. This way you have stronger boost because the turbo is not wasting any exhuast gas until it is at you set boost limit.

Hope this helps.

 

[DeezNutsForYou]

So your saying there would be less spool time with a ball and spring. I don't know if I believe that, my car spools pretty quick.

 

[nine5raptor]

i thought mine spooled quick too with a bleeder, then I tried a ball and spring...night and day.

 

[DeezNutsForYou]

no shit, well I guess I'll have to try it. I just have to figure out how to make one.

 

[blinded]

Originally posted by DeezNutsForYou
I just have to figure out how to make one.

Here's the vfaq that I loosely followed to make one this weekend. It took me 2 hours to find everything (I hate Home Depot), but only about 15 minutes to put together, install, and adjust.

 

[nine5raptor]

try a westlake/ace hardware instead of home depot for these. I couldn't find the pieces at home depot, but ace had the ball and spring (I got a T from napa with the npt fittings for 2 sides and retapped the other for metric fine threads, then used a metric bolt with a wingnut--boost adjustment without any tools!)

 

[DeezNutsForYou]

thanks for the link, I went to vfaq but the stupid thing wouldn't work.