Runaway shut off valve (positive air flow valve)

[Frankentruck]

IMO any place is better than nothing.
There are always situations where one design may work better than another, or one may have more drawbacks than the other.
I think NTPA requires the damper style.
Google [Diesel Runaway on Dyno] and see Tyler Burkhard's duramax having a bad day on the dyno at UCC a couple years ago.
If I remember correctly a big nitrous backfire blew the intake and piping apart. Then the engine started running away on its own oil.
A guillotine in front of the turbo would have been useless. Likely in this case any other mechanical system would not have worked either.
They used up several fire extinguishers before it finally quit.
There is a case for placing it as close to the engine's intake as possible. If turbo cold piping has failed shutting air off to the turbo won't stop it.
The post turbo butterfly near the engine system may create small boost leaks or fail when needed.
All reasonable arguments have merit.
Try what you think will work for your situation.

I've tried but never gotten information on what went wrong when Turba Tom's truck failed to shut down at Rocky Top Diesel Shootout last year.
It ran off the end of the track and he was killed. An unfortunate chain of events aligned for sure.
I wanted to analyze the details to try to come up with systems that might prevent similar instances in the future.

I like the old saying "if it can happen, it eventually will".

 

[Will L.]

Agree w/ out new friend from NC. Something better than nothing.

The gate/guillotine style can work but isn’t legal most places racing or msha anymore. But if thats what you can put together- better than not having one for sure.

The butterfly works perfectly regardless of pressure vs vacuum. Because yes one side of the butterfly is fighting the air pressure, the other side is helping it. Top side gets pushed in by all that air with identical force that is fighting the bottom side.

Personally- I prefer a big pull cable. When my adrenaline is going, be lucky if I don’t pull the engine back to inches! Haha. The heavy spring to auto shut and a cable holding a latch is really common- but if the latch gets work from all the vibrations over the years- random engine shutdown. But really nothing wrong with it. Wanna test it out good, build it and bolt to your local fire hydrant- If it stops that water flow- you’re golden!


What is best is closest to cylinder. If pre turbo and you get run away- then your hose from turbo to intake pops off from 60psi- that gate is stopping nothing on front of the turbo.

 

[Frankentruck]

Agree w/ out new friend from NC. Something better than nothing.

The gate/guillotine style can work but isn’t legal most places racing or msha anymore. But if thats what you can put together- better than not having one for sure.

The butterfly works perfectly regardless of pressure vs vacuum. Because yes one side of the butterfly is fighting the air pressure, the other side is helping it. Top side gets pushed in by all that air with identical force that is fighting the bottom side.

Personally- I prefer a big pull cable. When my adrenaline is going, be lucky if I don’t pull the engine back to inches! Haha. The heavy spring to auto shut and a cable holding a latch is really common- but if the latch gets work from all the vibrations over the years- random engine shutdown. But really nothing wrong with it. Wanna test it out good, build it and bolt to your local fire hydrant- If it stops that water flow- you’re golden!


What is best is closest to cylinder. If pre turbo and you get run away- then your hose from turbo to intake pops off from 60psi- that gate is stopping nothing on front of the turbo.

I considered the adrenalin factor and started to go with big push pull cable, but opted for the simplest route (being a solid core choke style cable with minimal excess and a sturdy bracket for now.

Hope I never need it.