ok, so i have a shitty Home depot MBC that i made last year, and it randomly modlulates between ~8psi and 13psi, sometimes it holds strong @ 13, and sometimes strong to 7-8psi, after much thinking about it... its GOT to be the MBC and NOT the wastegate, etc. think i might just have a crappy/slightly bent spring... how stiff of a spring should i be using? is a lighter or stronger spring gonna yield more consistant pressure? i would THINK the stronger one would, but would require more fine adjustment, what do you guys think?

going to the track today, hopefully running 12's
(shitty MBC made from this diagram http://www.geocities.com/chmwatson/FAQs/mbc.html )
http://youtube.com/watch?v=xpPjad5PaAU

 

did you drill the small hole? If the hole doesn't work, try this one:

http://www.grainger.com/Grainger/wwg/start.shtml # 5z763

 

When your at the junk yard pull a couple detent springs from any honda manual transmission, they are nice and stiff and work well.

 

any decent auto parts store will have a good spring selection.

i used a fairly stiff spring. I had a weak one and it didnt work too well.

also

at first i was using a steel ball bearing, and found it was too heavy to work accuratly

so i threw an airsoft BB in there and holy ---- that ****** is quick now.

if you can find an aluminum airsoft BB that would be ****. id use one but they dont sell em in canada.

 

i might just try a airsoft pellet, lol... went to the track, ran a 13.6x (ran a 13.366 last year) so i obviously couldnt get it working. after ---- warms up and/or cycles boost a few times, it will go from 12-14 psi down to 8ish, and its not like falloff from inefficiency or anything... real strange, might try out a grainger valve. might also route the WG reference to the TB so i gain another 1-2 psi from pressure drop from the IC (its referenced at the comp. housing now)
vid of the day at the strip : http://youtube.com/watch?v=xpPjad5PaAU

 

www.mcmaster.com

plastic: 9614K54

aluminum: 34665K29

 

i tried to buy oil lines from them.. they slip only very limited items to Canada...