I have built one and used it on My WRX (Subaru) with great success and cost maybe $15 dollers tops! Go to your local hardwre store and pick up a brass t that has femalethreads aproximately 3/8 to 7/16 inside diameter (make shure it dosn't have pipe threads) allen set screw plus same size nut, 3/8 by 1in. light pressure spring, 3/8 diameter ballbearing, .010 pen drill! 2 1/4 to 3/8 (depending on your vacuum hose id)barbed hose adapters! first place ballbearing inside of t (bottom horizontal portion of t) place spring against ball bearing to hold into place then thread allen set screw into end of t (to increase or decrease spring pressure against ballbearing! Don't forget to place thread nut onto set screw before threading into t (acts like a jamb nut to maintain set screw setting) next drill .010 hole in opposite side of t (prevents turbo pressure stacking, boost spikes) place rubber hose that sees manifold (or intercooler pressure, basically were you get your source for your boost gauge) Some turbos have a nipple right on the turbo outlet (best source) connect this line to the side of t that has the ballbearing in it! place hose on remaining barb and connect it to the waistgate! Principal of it is when the turbo builds up enough pressue to unseat the ballbearing it is routed through the t causing the waistgate to open dumping the excess pressure! Just remember to always atart on the conservative side when your making your boost adjustments! Have fun guys! Oh ya one more thing this little device enabled my otherwise bonestock WRX to run 13.7 to 13.8 in quatermile from a base time of 14.3 ET
Turbo Tim
TY 4 Stroke Master
Wow thats a fast Subaru !
Thats what 16lbs boost in all 5 gears will give ya! Broken rx
You could also make this into a two stage by incoperating an electronically controlled air solenoid before the t to route to another t that has either a higher or lower boost setting!
sledheadgeorge
TY 4 Stroke God
broken RX said:
Post pics if you can. This sounds interesting.
Sorry but I don't have any digital pictures of the set up! You might be able to find some ona WRX based web sight (forum) similar to what I had built, do a search with the heading "Home made boost controllers" You might also find someone that sells them for cheap money! I don't see why you couldn't use one thats built for a turbo car just might have to change the barbed ends to match your hose diameter! They both function the same and use the same methods to control boost preasure! Broken RX
snowy1
TY 4 Stroke Guru
boostcontrollers.com $40
Freak
TY 4 Stroke Junkie
Ebay $10 for a cheap one. I chose the Turbosmart boost controller because it has a spring in it that keeps it from releasing pressure until boost builds. $69 ebay.
mmmkokanee
Expert
http://www.geocities.com/chmwatson/FAQs/mbc.html
check this...its what i used on my awd turbo mitsubishi for years
check this...its what i used on my awd turbo mitsubishi for years
Thats exactly the same one that I had built for my WRX, its very easy!!!!
treewhacker
Expert
What's the advantage of this one over the one that comes on Bender's turbo?
Cheap, easy to build and adjust- and you can set up a two stage version with your preset boost levels not someon elses! You can also set it up with a throttle swith to engage 2nd boost setting at WOT!!
As RXHaller explained to me last week 
this sounds like a real good idea.Instead of laborating with different jets,why not install two or even three switches?
According to the electric ones,howe does it work?!
this sounds like a real good idea.Instead of laborating with different jets,why not install two or even three switches?According to the electric ones,howe does it work?!
you would a boost controller for each boost setting you would like! The pressure line (boost pressure) would be tapped with an electronically controlled airsolenoid valve= 1 in put (from turbo) 2-3 outlets depending on what you want to use (grainger industrial sells them) outlets would go to each boost control valve that you are using, they can be controlled by toggle switches mounted by your gauge pod or you could use a swicth similar that is used in nitrous kits for cars! Lets say 6-8lbs set on first valve and once the throttle is pegged it engauges the throttle position switch electryfing the solenoid routing the pressure to your second boost control! Another important note, just like nitrous its a lot easier on the motor when its engaged at higher rpms, less chance of engine damaging detonation!!
I've never liked the jet method for controlling boost, you might as well go down to your local pet store and get yourself a $5 fishtank valve! Which you could adjust but is inconsistent! and could cause boost spikes! For those that don't know what a boost spike watch your gauge when you pin the throttle does the boost go a couple of pounds higher than what it set at then drops back down! That is what they call boost spikes or pressure stacking! With a properly set up boost control that has a bleed feature you won't get this! It'll jump to where you have the valve set at and stay there!!
