In addition to using the wastegate to control boost if the meth injection system fails to deliver its engine saving spray, can we use the BOV as well to dump boost and keep the turbo from stalling?

Let's say the 12 VDC output from a failsafe system can be used to trigger on a pressure switch set at the max boost allowable to run pump gas, let's say at 20 psi. This pressure switch will open an on/off solenoid valve that is Teed into the BOV line whenever the failsafe is activated and the boost is above 20 psi. The solenoid valve outlet is routed to the intake before the turbo after the filter. The boost in the BOV line will take the path of least resistance from the boosted intake manifold to the vacuumed intake. The BOV will not see boost from the line and open since the UICP is still boosted. The BOV will rapidly, if not immediately, dump pressure until it hits 20 psi when the boost line solenoid valve will close.

I'm pretty sure this will work. I think it's worth it too. I think this would decrease the response time of just having the wastegate reduce the boost. The boost already generated before failure will still make its way into the engine. Physically dumping the boost will minimize this. I think using both wastegating and blowing off would be superior to just wastegating.

Dumping boost (VTA) in this fashion would likely create a temporary rich condition which would also be helpful in minimizing chances of detonation. In a draw through MAF situation this would be a lot. A speed density maybe a little, I'm not sure.

Plus, when you have pressure built and dump the wastegate, you stall the turbo, which places increased forces on the turbo. Dumping the BOV along with the wastegate minimizes this too. This would keep that turbo spinning to nicely transition from W/AI to no W/AI. I think this would "smooth out" the failure.

Also, a VTA while hard on the gas (not lifting on the throttle) would strike you as an odd occurrence and give you an audible heads up on what's going on in addition to whatever indicator you have. I'm sure the loss of power does that too, but whatever.

So what do you guys think?

 

Me thinks itza definitely a possible plausibility anda ita mighta even work.

 

You are basicly setting up your BOV as a pop off valve. They used those back in the turbocharged days of F1 racing. If a team tried to cheat by running higher boost than the other teams the pop off valve would open up and vent all boost pressure to atmosphere.... had to go back to the pits to re-set it.... and adjust the boost down to prevent it from happening again

Using the BOV as a pop off valve is a great idea. A simple solenoid valve controled by the same pressure switch that controls the "spray on" light for the SMC kit will not work though because the "spray on" light only activates when you are already into boost.

Your solenoid valve leading to the intake between the turbo and the air filter has to be closed for the BOV to be closed under boost right? So if the solenoid opens if the alcohol kit is not spraying, and you are not spraying until after you get positive boost pressure.... then the solenoid is never going to close and you will never even get to positive boost pressure.

I have no doubt there is some way to do it, but I am up to late to think of it now

Keith

 

Sounds like an awsome idea...... lets do it.

 

You need a simple control board to make this work, perhaps some electonic guru can help us out. The board needs an input from a boost pressure switch and an input from the pump output pressure switch.

Logic one: If there is not boost pressure signal above value "X" the solenoid stays closed.

Logic two: If there IS boost signal above value "X" AND alcohol pump output pressure signal above value "Y" the solenoid stays closed.

Logic three: If boost value is above "X" and pump output pressure is below "Y" the solenoid opens and uses the BOV as a pop off valve.

I bet you that if we aproch SMC with this idea they will incorperate it as a failsafe in the next generation SMC kit.

Keith

 

This is how I would do it:

Use the an existing failsafe system that detects a fault in the operation of whatever W/AI system you are using and sends a 12 VDC signal. This signal can be used to operate a transistor or a relay. When this relay is actuated by this signal, a circuit which contains an adjustable pressure switch that sends a 12 VDC signal when the pressure is above the set value, will be closed. This way the BOV is dumping ONLY when then the failsafe is active AND the pressure is above a pre-set level. This signal will operate a fast wide open or tightly shut solenoid valve that that springs back to closed when unenergized.

This mod will now be known as the EVOgasm mod from now on.

 

Man, thats a really good idea.
Let us know how it turns out.