Forum > Forced Induction

2 stage junk yard boost control



--- Quote from: Big J ---Total cost in the boost controller so far, less than $20.


The top port of the wastegate usually sees atmospheric pressure, so when the manifold is at 0 on the boost guage, the same amont of atmospheric pressure is acting on the bottom of the wastegate diaphragm as the top, at that point there is no pressure differential across the diaphragm. Like when the car is off.

I use a pressure regulator as a boost controller by altering the pressure differential acting on the diaphragm. If my wastegate spring stabilizes at 5 PSI w/o help form the boost controller, for every 1 PSI I regulate to the top port I increase my manifold boost by 1 PSI by altering the pressure differential, so to equal out pressure now it requires atmospheric + 1 psi on the other side of the diaphragm that sees manifold pressure. 2 psi regulated pressure equals atmospheric + 2 + the 5 the spring regulates, for a total of 7PSI.

Now anyone with a boosted spec knows 1st and 2nd gear are almost usless at 10 PSI, that's life. Now at say 5 PSI they're much better. If my spring allows me to run 5 psi, and w/ the boost controller I run 9-10, how can I run 5 then switch to 9-10?

An air solenoid. If I vent the pressure from the line feeding the pressure regulator I'll run 5psi, when I stop venting it'll run 9-10. So if I set up the soleniod tee'd into the signal line to my boost controller to vent when activated, I'll run 5psi. If I use a n open when powered solenoid, I can use a button mounted to my shifter to run run 5 psi whit the button pressed. That means I can leave the line in first gear at 5 PSI, shift to second at 5 PSI, and let off of the button when I shift to 3rd to run 10 PSI the rest of the run.

Nothing new, just putting it out there.

With the circuit open, air, boost or vaccum, will pass freely between 1 & 2.

With the circuit closed, or energized, air will pass freely between 1 & 3.

#4 is a filter to cap off whichever tube you vent.

Port 1 would go to the top port of the wastegate, between the GW and boost controller. Port 2 would go to the boost controller, and port 3 would vent.

when unenergized air will pass from the boost controller to WG like normal. When energized, port 2 would be blocked from the boost controller, and the top port on the WG would open to the atmosphere like there was no boost controller hooked up.

The button was fine but you have to remember to hold it down and fight the car w/ one hand:

Finally got around to making this automatic, first spec ever with Ghetto Traction Control (GTC). 1st and 2nd gear now automatically run 5psi. I plan on wiring in an override switch for what ever occasion would need me to run more than 5 psi in first and second. 3rd and up runs whatever the boost controller is set to.

This is how I was doing it, some times it gets harry trying to fight the spec w/ one hand when it makes whatever the hell it makes in 1st and 2nd at 5psi.


Ghetto Tech custom fab work, need to make the ground wire prettier to be Ghetto Tech Certified.

This is a the selector lever on the transmission, for 1st and 2nd the arm swing as closes the switch and vents the MBC, for the rest of the gears the switch is open and the car runs what ever the MBC is set for

I think I'm going to wire the over boost function into the windshield wiper spray switch because I got rid of the washer fluid jug to relocate my battery. There is no need to ever overboost on anything other than a straight away, using the washer lever I can keep both hands on the wheel when laying on the extra power

Just because it's cheap doesn't mean it's crap.

If had $300 to drop I'd just get an AVCR or World Sport EBC, but I get bored and like to make stuff work.
--- End quote ---

I hope this gets stickied so I can find it later. ;D


[0] Message Index

Go to full version