# Two stage boost controller for VRT DIY



## phatvw (Aug 29, 2001)

*Two stage boost controller for VRT/1.8T DIY*

UPDATE: It appears one of the solenoids failed causing severe overboost
because it blocked air to the wastegate port completely. I didn't think it was
possible for these solenoids to fail that way - I figured if they were to fail, they'd
fail in the open mode thus defaulting to low boost. But if one fails in the closed
position thats real bad.

---------
I built myself a two stage boost controller for my VRT.
I bought a solenoid device from 3bar-racing.com last year, but it never really
worked quite right; it either overboosted or had a vacuum leak and was quite
sensitive to temperature changes. Also the supplied solenoid was difficult to
mount in the MkIV engine bay.
So I made my own.

Circuit diagram:
http://www.parts4vws.com/image...2.GIF

Parts:
# 2 OEM GM solenoids [ACDELCO Part # 214474 {#01997152}]
# 2 OEM GM wiring harnesses with 12" leads [ACDELCO Part # PT374 {2-WAY FEMALE BLACK M/P 150 #12102747}]
# manual boost controller (MBC) - Turbo folks should already have one of these
# 3 feet of silicone tubing (less depending on location of solenoids)
# vacuum tees & couplers
# zip ties
# nuts (M6x1 for MkIV installation)
# washers (1/4" or M6 for MkIV installation)
# electrical wire
# solderless wire taps
Install Notes:
# Remove the foam filter and metal clip from the solenoid prior to install
Advantages compared to 3bar-racing:
# GM solenoid has built in mounting tab - mounts on firewall in MkIV
# twin solenoid design prevents potential overboost/vacuum-leak problems
# twin solenoid design is more robust for high boost applications
Engine bay pics: 
http://phatvw.spaces.live.com/...4!140/

GM Solenoid: (click for description from wikipedia)
http://upload.wikimedia.org/wi...d.jpg

Review:
# I have tested v2.0 with the wastegate set at 5PSI and the MBC at 9-10PSI at the
local racing circuit. I just flip my OEM fog-light switch to get an extra 50HP. V1 used
a single solenoid and a check valve - much cheaper, but less reliable in the long run.
# Track testing showed no boost leaks or solenoid issues.
# Instead of switching between wastegate and MBC, you can switch between 2 MBC's
# It took a little time to adjust the manual boost controller to my desired setting of
9PSI. Because there are actually three valves in series, the system becomes a little
more sensitive to changes, so you have to be careful to change the MBC setting no
more than 1/4 turn at a time when setting boost.


----------



## IN-FLT (Mar 22, 2003)

looks good so far! cant wait to see the pics


----------



## nubVR (Apr 25, 2004)

*Re: Two stage boost controller for VRT DIY (phatvw)*

Yeah im interested man! I have yet to get my MBC, i need to get on that soon.... But it sounds like a good set up. So do you run it off your fog, or the Rear fog switch?


----------



## stealthmk1 (Aug 17, 2001)

*Re: Two stage boost controller for VRT DIY (nubVR)*

Very cool. Looking forward to pics and more info. http://****************.com/smile/emthup.gif


----------



## rickyrunamuk (Sep 13, 2004)

Nice work!


----------



## phatvw (Aug 29, 2001)

*Re: Two stage boost controller for VRT DIY (nubVR)*


_Quote, originally posted by *nubVR* »_Yeah im interested man! I have yet to get my MBC, i need to get on that soon.... But it sounds like a good set up. So do you run it off your fog, or the Rear fog switch?

I'm just using the front fog light wiring that came with the car since those wires are unused with my OEM HID's. Running a new wire from the rear foglight position in the Euroswitch should not be very difficult. I think the solenoid is only rated at 1-amp, so the foglight wires are more than enough.

Pics added above.


_Modified by phatvw at 3:47 PM 12-23-2007_


----------



## bdcoombs (Jul 28, 2002)

*Re: Two stage boost controller for VRT DIY (phatvw)*

i can see it now you sell the car and we get a post saying my car is twice as fast when the fog lights are on
haha nice work


----------



## jmaddocks (Jan 31, 2004)

*Re: Two stage boost controller for VRT DIY (bdcoombs)*

Nice job! http://****************.com/smile/emthup.gif 
No kidding, for the last couple of weeks I've been planning to grab a vacuum solenoid from the junkyard for the same purpose. Goal was to control the solenoid w/ the cruise control button for a poor man's launch control (7 psi vs. 21 psi for my setup). Thanks for the writeup and pics.


----------



## bigbumpmike (Aug 26, 2003)

thats pretty cool and great info... i also just thought of for the 1.8t guys that want to run a mbc this would work great and use a micro switch under the gas pedal to activate the high boost. i wonder also if this would work for 2.0t bc i like having a chiped car just i would like to hold 15psi all the way instead of boost falling off so much.


_Modified by bigbumpmike at 3:32 PM 12-26-2007_


----------



## BLSport (Dec 24, 2005)

*Re: Two stage boost controller for VRT DIY (phatvw)*

Only one issue; your check valve has defeated the small bleed-off port of your MBC in high-boost mode. In this mode, pressure will be trapped in the wastegate diaphragm even after boost pressure decreases at the boost port of the MBC, until you switch back to low-boost mode when the pressure can escape back to the manifold.
What you can do however is eliminate the check valve, and run a ganged-valve solenoid (if you can find the right combination of input/output and open/closed) or two solenoids simultaneously to achieve the result you're looking for without defeating the MBC's bleed-off port. http://****************.com/smile/emthup.gif


----------



## phatvw (Aug 29, 2001)

*Re: Two stage boost controller for VRT DIY (BLSport)*


_Quote, originally posted by *BLSport* »_Only one issue; your check valve has defeated the small bleed-off port of your MBC in high-boost mode. In this mode, pressure will be trapped in the wastegate diaphragm even after boost pressure decreases at the boost port of the MBC, until you switch back to low-boost mode when the pressure can escape back to the manifold.
What you can do however is eliminate the check valve, and run a ganged-valve solenoid (if you can find the right combination of input/output and open/closed) or two solenoids simultaneously to achieve the result you're looking for without defeating the MBC's bleed-off port. http://****************.com/smile/emthup.gif 


Yes I considered the twin solenoid design, but that increases cost quite a bit. I may ultimately go that route since it will be more reliable overall. The one-way check valves are not the best construction, I suspect the one I have may actually be leaking in the reverse direction at high boost. But these solenoids are bulletproof!

If instead of a manual switch, this was a throttle controlled switch from the TPS sensor or the pedal itself, then there would be no problem.
I am currently testing the check valve design and it is working quite well. Boost builds every time. The only issue I have is if I flick the boost switch when I already have the throttle down.



_Modified by phatvw at 11:14 AM 12-26-2007_


----------



## jmaddocks (Jan 31, 2004)

*Re: Two stage boost controller for VRT DIY (phatvw)*

Is the purpose of the check valve to prevent the manifold pressure signal from leaking out of the mbc's bleed-off port when the vacuum switch is open?


----------



## phatvw (Aug 29, 2001)

*Re: Two stage boost controller for VRT DIY (jmaddocks)*


_Quote, originally posted by *jmaddocks* »_Is the purpose of the check valve to prevent the manifold pressure signal from leaking out of the mbc's bleed-off port when the vacuum switch is open?

That is correct. What happens is that you can get overboost in the "low boost" setting because of the bleed. Usually this would not be a problem, but because the solenoid acts as a restrictor, the signal to the wastegate can change quite a bit depending on the orifice size of the bleed.


----------



## Noobercorn (Aug 17, 2007)

*Re: (IN-FLT)*

this is awesome!!!!!!!!! great work!!! i will forward this link around. you SHOULD sell these!!!


----------



## phatvw (Aug 29, 2001)

*Re: (Noobercorn)*

BTW here is the more robust twin solenoid design I was talking about:











_Modified by phatvw at 2:23 PM 1-13-2008_


----------



## BLSport (Dec 24, 2005)

*Re: (phatvw)*

Rock on! http://****************.com/smile/emthup.gif


----------



## phatvw (Aug 29, 2001)

*Re: (BLSport)*

So I think my check valve is leaking or something else is going on with the v1 setup.
When the car gets nice and hot after 30 minutes of driving, I have a boost leak. I hit peak boost @9PSI and then it drops down to zero by redline when the switch is in "fast" mode. I'm going to order some more solenoids and test the twin solenoid v2 setup next.


_Modified by phatvw at 6:50 PM 12-31-2007_


----------



## jmaddocks (Jan 31, 2004)

*Re: (phatvw)*

Maybe you're trapping high pressure air between the wastegate diaphragm and check valve, thereby keeping the wastegate open (or making it easier for exhaust pressure to open the wastegate)?


----------



## phatvw (Aug 29, 2001)

*Re: (jmaddocks)*

Could be. I'll play around with it. Could just be a bad hose though - it sure is a jumble in there.


----------



## Salsa GTI (Aug 29, 2000)

*Re: Two stage boost controller for VRT/1.8T DIY (phatvw)*

what is the part number for the solonoid or what vwhicle does it come on?


----------



## phatvw (Aug 29, 2001)

*Re: Two stage boost controller for VRT/1.8T DIY (Salsa GTI)*


_Quote, originally posted by *Salsa GTI* »_what is the part number for the solonoid or what vwhicle does it come on?

I was told by a friendly fellow on VWVortex not to post the part number until I decide whether to offer a kit for sale and become a VWVortex advertiser.
But I'll give you a hint - its from a Pontiac with a factory turbo - there are not many of those


----------



## Noobercorn (Aug 17, 2007)

*Re: Two stage boost controller for VRT/1.8T DIY (phatvw)*


_Quote, originally posted by *phatvw* »_
I was told by a friendly fellow on VWVortex not to post the part number until I decide whether to offer a kit for sale and become a VWVortex advertiser.


i agree that you eare entitled to a fee for your work. http://****************.com/smile/emthup.gif 
eff dave (salsa) he is a noob anyway. let him figure it out himself. hell, he is old enough he should know this off the top of his head.


----------



## rickyrunamuk (Sep 13, 2004)

Does it talk to David Hasselhoff?


----------



## phatvw (Aug 29, 2001)

*Re: (rickyrunamuk)*


_Quote, originally posted by *rickyrunamuk* »_Does it talk to David Hasselhoff?

No, but it runs linux.


----------



## Salsa GTI (Aug 29, 2000)

*Re: Two stage boost controller for VRT/1.8T DIY (Noobercorn)*


_Quote, originally posted by *Noobercorn* »_
i agree that you eare entitled to a fee for your work. http://****************.com/smile/emthup.gif 
eff dave (salsa) he is a noob anyway. let him figure it out himself. hell, he is old enough he should know this off the top of his head. 

Yes I should and have the part in hand








Funny thing about having old age and unlimited access to cars








I will be implamenting this in the neer future.....to bypass the regulator and run off my 12 psi gate spring.
SO to get more use out of first and second








I can tell you what vehicle it comes on........
FOr one hundred Billion dollars.........


----------



## phatvw (Aug 29, 2001)

*Re: Two stage boost controller for VRT/1.8T DIY (Salsa GTI)*

I got a 2nd solenoid to build v2.0 and will be testing it for a couple weeks. Initial impression is that it appears to hold boost better in "high" mode.



_Modified by phatvw at 8:18 PM 1-9-2008_


----------



## IN-FLT (Mar 22, 2003)

*Re: Two stage boost controller for VRT/1.8T DIY (phatvw)*

great news! looking forward to the progress of V2


----------



## Jefnes3 (Aug 17, 2001)

*Re: Two stage boost controller for VRT/1.8T DIY (Noobercorn)*


_Quote, originally posted by *Noobercorn* »_
eff dave (salsa) he is a noob anyway. let him figure it out himself. hell, he is old enough he should know this off the top of his head. 










How can you call Dave a 'noob' wearing glasses like those?









-Jeffrey Atwood


_Modified by Jefnes3 at 8:08 AM 1-10-2008_


----------



## Noobercorn (Aug 17, 2007)

*Re: Two stage boost controller for VRT/1.8T DIY (Jefnes3)*


_Quote, originally posted by *Jefnes3* »_
How can you call Dave a 'noob' wearing glasses like those?









-Jeffrey Atwood


lol, cause i like bustin daves ballz. last time he came over for beers, that's all he did was bust mine. so, i gotta give it back. also, those glasses rock! no 2 ways about it!!!


----------



## Jefnes3 (Aug 17, 2001)

*Re: Two stage boost controller for VRT/1.8T DIY (Noobercorn)*


_Quote, originally posted by *Noobercorn* »_
those glasses rock! no 2 ways about it!!!

Agreed.
ON Topic: so when will this be available as a 'kit'?
-Jeff


----------



## Noobercorn (Aug 17, 2007)

*Re: Two stage boost controller for VRT/1.8T DIY (Jefnes3)*

co-branding for a C2 DSMBC???????


----------



## phatvw (Aug 29, 2001)

*Re: Two stage boost controller for VRT/1.8T DIY (Noobercorn)*

I would like to do some high-rpm/high-boost testing on the racetrack before selling
a kit. I think the first trackday of the season is in early February.

Here is tentative pricing if I can get 5 people lined up:

Barebones v2 kit: $75+shipping
2 OEM solenoids
2 OEM watertight wiring harnesses with 12" pigtails
4 solderless butt connectors
I can put together full or partial install kits as well, or you can just get that stuff
from your local hardware store. You'll still need your own MBC.
I was browsing ebay and it appears there are quite a few 2-stage designs. Some use
one solenoid that rapidly switches - you set the duty cycle with a variable resistor.
Those designs are about $70. Others appear to have the MBC integrated along with 2
solenoids - those designs cost upwards of $150.
I don't see any other designs which are meant to work with an existing MBC and use
the solenoids as simple switches. I believe my design is the most flexible and robust
- it just needs more testing to prove it.


_Modified by phatvw at 2:28 PM 1-10-2008_


----------



## phatvw (Aug 29, 2001)

*Re: Two stage boost controller for VRT/1.8T DIY (phatvw)*

*Full part numbers provided above* I don't have time to put together kits, so go
build your own. This works great on the racetrack. Inexpensive and very effective
modification.

If you find this useful, I will gladly accept beer - virtual or otherwise.

























_Modified by phatvw at 12:37 PM 3-11-2008_


----------



## phatvw (Aug 29, 2001)

*Re: Two stage boost controller for VRT/1.8T DIY (phatvw)*

Another day of track abuse with this setup. This time I removed the windshield/cowl ->
engine-bay seal to get some additional airflow over the turbo. Helped to keep temps
down and cooled the solenoids too. Those suckers get hot!
Anyway, with both high and low boost modes this setup is flawless! I did 3 30-minute
sessions and one 15-minute session on track. Oil temps leveled out at about 265° as
measured at the oil-pan, so you can imagine how hard I was running. Switched to low
boost for the twisties to help manage the freight-train amount of torque, and up to
high boost on the front straight to pass all the slow-ass Porsches and ClubSM
race-prepped Miata's. The only car that was consistently faster than me in both
straight and twisties was a Porsche 914. I don't know what kind of engine he had,
but it was hella-fast. And everyone knows how well those thing handle in the corners!!
You need this mod for your street/track high-HP turbo car!



_Modified by phatvw at 6:47 PM 4-1-2008_


----------



## nubVR (Apr 25, 2004)

*Re: Two stage boost controller for VRT/1.8T DIY (phatvw)*

congrats on gettin it dialed in man..... I havnt had a chance to get mine up and runnin yet!


----------



## phatvw (Aug 29, 2001)

*Re: Two stage boost controller for VRT/1.8T DIY (nubVR)*

Update: I beleive one of the solenoids failed causing severe overboost because it blocked air to the wastegate completely. I didn't think it was possible for these solenoids to fail that way - I figured if they fail in the open position its no problem because you get wastegate boost, but if one fails in the closed position thats real bad.
I pulled the solenoids out and tested them by blowing in all the ports and hooking it up to power. It operates normally at my ~1PSI lung strength. I suspect that it only fails at higher pressure i.e. the high pressure causes the mechanism inside to switch and shut off the wrong port.
I don't know if I want to spend any more money on this project. I challenge someone else to extend what I've done here and design it so that all failure modes default to low boost. Perhaps simply using both ports on the wastegate as per Tial's recommendation or using a more robust solenoid?


_Modified by phatvw at 11:41 PM 4-12-2008_


----------

