Grog

iTrader: (9)

Kinda long, just a little technical...

I've tried several different bypass valves, all recirculated, with little success in holding all the boost pressure I need without leaking or part-throttle flutter...stock, Forge DV, Forge RS DV, 1G...

By far, the best-performing valve for daily-driving so far has been the 1G. It may or may not leak right now at ~20 psi, haven't checked. But with my turbo upgrade, water injection, and more boost, I know it won't hold. I'll need another valve solution, and switching between valves (Forge RS for track days, 1G for daily driving) is not a solution I want.

The "Gus Mod" for the 1G valve looks like a great option. But I want to be able to switch between an intercooler pressure source for daily driving and atmospheric for high-boost at track days without plugging/unplugging lines, capping open pressure sources in the IC pipe, etc.

There are two options. The first would be pressure-controlled like the Dejon Tool kit. The other is TPS-based with a WOT switch. The pressure-controlled option has one main potential issue...when boost pressure is at/around the pilot pressure (15 psi for the Dejon kit), the switch could flutter between open and closed, causing some driveability issues. The WOT switch option looks like it will perform better under all conditions, but is much more costly ($50 for the Dejon kit already assembled vs. $70-100 for a WOT switch intended for nitrous activation + solenoid valve controlled by the WOT switch + lines, fittings, etc.)

So the questions:

1. Does my concern about pilot-pressure switching make any sense? If the valve can hold >15 psi without leaking, could the flutter ever occur? Has anyone used the Dejon kit with a 1G valve in track-day situations? I've yet to track my car, but will spend some time next season in HPDE events and such and it needs to work.

2. Is there a cheaper option for a WOT switch than the ones for nitrous?

3. Where could I find a 3-way solenoid valve for use with 1/4" +/- vacuum lines? I've found a couple of options that would work, but have only found manufacturers, not retailers. Any ideas?

I'm intending this thread as a resource for DIY'ers who don't believe in expensive aftermarket units (noise-makers) but want to run higher boost, so any additional info related to this mod is greatly appreciated.

Thanks. And yes, I did search.

Fourdoor

iTrader: (11)

The GM boost solenoid has a boost source, and boost signal port with a third port that is vented to atmosphere for when the solenoid is not active, would that work for your needs? If the "Gus" mod is the one I am thinking of, you block the small hole, in the seat area of the bottom of the 1G BOV and tap into the air passage with a threaded pipe to either vent the line to atmospher (high boost) or supply it from the upper IC pipe (fast reacting low boost mode). The GM valve is closed when power is supplied, and open path from boost source to what ever device you are supplying (be it WG actuator normally, or in your case the BOV air passage you tapped into) when no power is supplied. If this would work for your needs you can purchase it along with the wireing pig tail from any GM dealer, check the AEM EMS forums for part numbers.

As far as your signal controling the solenoid, the WOT switch would work great for both daily driving and track days. I am not sure how the Dejon tool kit works, where the boost reference source is and whatnot, so it is hard to advise you on that one.... do you have a link showing what you are considering? Pilot actuated relife valves are used in industry for safety reliefs, but they sometimes fail to re-seat correctly after relieving pressure. Good for safety, not so good in a system that goes through rapid changes constantly.

Later,

Keith

Fourdoor

iTrader: (11)

You may get more responses in the "advanced" forums. If you want me to move your post there just say so and I will move it

Keith

Grog

iTrader: (9)

Yeah, that would be great! Thanks! Wasn't sure if this would be considered "advanced" enough to be in the advanced section since it deals with bypass valves .

Here's a link with Dejon's description:

http://evo.dejonpowerhouse.com/ then go to bov-misc-tools. 2/3 down the page.

Basically it uses manifold pressure as the "switch": you tee off of the BOV line. >15 psi switches to atmospheric pressure, otherwise it's the IC pipe pressure. You have to either have or drill in a pressure source in your intercooler piping. Not sure where they sourced the valve from...I went ahead and ordered their kit, so I'll find out shortly who makes it.

The GM solenoid sounds like it would work. Any cheaper options for a WOT switch aside from the (relatively expensive) nitrous ones?

Thanks again!

Fourdoor

iTrader: (11)

Actually, if it is a high quality pilot valve it should work well in that configuration. Since it just switches the pressure source around a bit it isn't really being used as a pilot valve, so should give none of the "not re-seating" issues I was concerned with in my post above.

The kit comes with all the parts you need to do the BOV modifications, along with the pilot valve as well.... so I would only worry about the GM solenoid and WOT switch if the dejon kit doesn't work as well as it should.

Keith

kjewer1

iTrader: (4)

The answer to your question depends largely on the turbo you intend to run. On a quick spooling turbo like the stocker, any pressure based control, wether it's via the hobbs switch system or the pnumatically acutated valve, is going to still have some issues. Mostly around part throttle/maintenance throttle, where small turbos can still make more than 15 psi or whatever your switch point is, and give you some driveability problems when boost comes back down (which can happen even with no reduction in throttle position). A better solution is the WOT switch, the valve only vents the fast release port at WOT, which seems to work much better.

You can either use a micro switch from radio shack or similar, which some poeple have had good luck with, or you can just wrap the wire around the striker on the TB shaft (where the cable mounts) with some insulation, so when the throttle hits the stop it's grounded through the TB body. This has also worked very well for poeple. Sometimes the simplest solutions are the best solutions. I personally used the DSMlink nitrous controls to actuate the valve and basically set it up to run solely on TPS. Same concept, worked great.

trinydex

iTrader: (12)

the flutter will only happen if you're at the pilot pressure and your bov can't hold it (uncrushed) otherwise it will hold it fine without any problems.

i have a flutter on mine becuase i choose not to crush my valve, i could but i choose not to. it also does not affect my driveability.