calculon

iTrader: (29)

Anybody got a link to any sort of ELECTRONICALLY actuated pop-off valves?

The reason I ask, is my AI kit has 2 output triggers that will signal in the event of AI failure. . .

1 will go to my haltech and tell it to switch maps to my tune with just pump gas

and the second i'd like to actuate said pop-off valve to instantly release all the boost pressure.

the necessary INSTANT release is what necessitates the elecronic actuation. I don't want it to be mechanically actuated by pressure controlled by an EBC-type of solenoid that is triggered by the AI output trigger, because then there will be a few combustion events that take place at that boost level, which defeats the whole failsafe idea.

thank you very much
ryan

ikari899

hey i gota idea, how about you just wire one of those outputs to the haltech and then configure the digital input to an ignition cut AUX revlimit and set it to like 1500 rpm? it will react much faster then any mechanical, as in some thing that has to move any distance, pop off valve and will run tons of unburned fuel though your engine cooling it off.

calculon

iTrader: (29)

this isn't a bad idea at all, the only problem, and i'm just not sure how big a problem it really is due to my inexperience/lack of education on the matter, is if i am detonating/auto-igniting and under boost, the motor is still gonna be toast. . .

although, like you brought to light, the fact that even an electronically actuated valve is going to have to move a distance, and therefor fail to provide IMMEDIATE reduction in pressure. i wish i could find same data sheets on electronic valves to get a feel for how fast they really are. i wouldn't find it hard to believe if there was one that opened in 1/100th of a second or less. hmmm. . .

thank you for the input, please feel free to bounce any ideas off of me and/or tell me that mine are dumb.

ryan

ikari899

ummm you could just as easily cut fuel instead of ignition, just check the other box, and then there will be nothing to pre ignite. which now that you mention it that would be the preferable way to stop pre ignition. ummm but i did find a valve for you here:
http://www.marotta.com/DataSheets/MV604C.htm
it will be useful to know this:
Cv Factor— Coefficient of volume. Amount of liquid in gallons per minute (at 60° F, specific gravity of 1) that passes through a fully-open valve with a 1 psi pressure differential. Higher Cv factor means a higher flow rate.

that valve opens in .015 sec but has a very low flow rate which might end up being a large problem for what you are using it for. and when you think about it it makes sense that all the very fast acting valves are going to have that problem because in order to be fast acting the valve has to be very lightweight which means very small = low flow. o well i stopped looking after i found that so maybe they have some made of crazy alloys but thats all i found. oh and mcmaster doesn't have any that are under 1 sec.

calculon

iTrader: (29)

thank you for the help. i appreciate it sincerely. the reality is, i just don't know enough/i'm not smart enough to know what's the best thing to do. like you brought up earlier, pumping fuel through without spark is wise because the heat can be removed, but there is the pre-ignition problem (potentially)

removing fuel will still leave some pressure behind, and potentially just enough fuel remnants to allow a very lean condition instead of the desired NO fuel effect.

looks like i'll just have to get a second kit that is always on, and is activated by the output from the primary kit (just kidding, but kind of not)

i hate myself

thanks again
ryan

Speed of light

iTrader: (8)

You could configure an auxilliary solenoid to apply vacuum to a blow off valve to accomplish this pop-off function.

ikari899

where is he going to find vacuum while under boost?

John Magnuson

From the intake before the turbocharger.

peejay

If there's any significant vacuum before the turbocharger, then he's got bigger problems.

Even the airflow meter that everyone says is "so restrictive" will cause about maybe 8 inches of water pressure drop. That's barely half of an inch of mercury, or a quarter PSI.

Speed of light

iTrader: (8)

The vacuum tank, if you still have one. If not, you could add a small can and a check valve to capture the vac to operate this valve--it would not have to be very large.

I used the EGR solenoid on an FD to accomplish this function. Unenergized, the blow off valve would receive manifold pressure as normal. Energize the solenoid to apply vacuum to the blow off valve and release the boost as desired. Hence the blow off valve operates as a normal blow off or a electrically controlled pop off valve.

Oh, and don't laugh at the suggestion of getting vacuum off the turbo inlet. A properly designed inlet and pick-up tube could easily get several inches of vacuum this way. No joke.