Safe alcohol

[John Purdom]

Hey folks,

Installing an alcohol kit soon. I need not tell you all of the $$$ invested in these engines. It appears that the SMC kit and Razor's are equally good. To be honest, delivery time will be the deciding factor. SMC seems to be at least a month behind at the moment..

At any rate, I know the pumps included in both kits are very high quality, but nothing is perfect. Sudden failure of a pump while at 25# on 93 is instant grenade. Has anyone considered, or worked out a pressure switch that would kill the ignition if the alky pump failed?

Thanks

 

[DMan]

I have seen vendors like Carroll's Supercharging in NJ and Aquamist in the UK carry parts and systems that include 'proof' switches (pressure sensors and flow meters) that measure the pressure/flow in the alky lines to ensure the alky is really there and flowing.

No need to kill the ignition - usually they are wired up to a boost pressure circuit that lowers boost pressure to a safe level when alky stops flowing.

 

[Hyboost4Banger]

Could happen. I find the reliabilty of these kits excellent. More likely scenario is the user is the problem, forgetting to check the alky supply level..... or running out of alky altogether.
Mark

 

[John Purdom]

Could happen. I find the reliabilty of these kits excellent. More likely scenario is the user is the problem, forgetting to check the alky supply level..... or running out of alky altogether.
Mark

Hi, Yep, considered that too. Nothing is perfect, 'specially me. Whatever the reason the alky would quit flowing, it would mean disaster. I can't resist the temptation to run 25# on the street, and this is the only way I can see to do it economically. However, if my new motor gets turned to shrapnel, the race gas would then seem cheap. Sayin'?

Just curious, has this happened to anyone on the board?

 

[Razor]

Scenario... alky kit quits spraying at 25 PSI... it kills the ignition.. motor shuts off.. you lose power steering and accessories like brakes as well.. you crash car.. Motor would have been cheaper.

Whats to say your fuel pump doesnt dive, or your fuel pressure regulator, or one cylinder doesnt fire... crank yanks piston down and slings a rod, or your hose on the compressor comes off..you boost to 40 PSI.. Then an Elephant falls on the car cuase it was one of those days

Many scenarios in racing.. no flow devices available economically. Gems makes one and its 175.00 just for the sensor. And pressure switches dont stop the issue of clogged nozzles... and add one more place for a breach to occur.

 

[John Purdom]

Scenario... alky kit quits spraying at 25 PSI... it kills the ignition.. motor shuts off.. you lose power steering and accessories like brakes as well.. you crash car.. Motor would have been cheaper.

Whats to say your fuel pump doesnt dive, or your fuel pressure regulator, or one cylinder doesnt fire... crank yanks piston down and slings a rod, or your hose on the compressor comes off..you boost to 40 PSI.. Then an Elephant falls on the car cuase it was one of those days

Many scenarios in racing.. no flow devices available economically. Gems makes one and its 175.00 just for the sensor. And pressure switches dont stop the issue of clogged nozzles... and add one more place for a breach to occur.

Points well taken. Thanks

 

[Hyboost4Banger]

If it makes you feel any better I run 35 psi on the street and have been for almost a year since I installed Razors kit. I've almost polished off my first 55 gal. drum......I carry 2 gallons of spare alky with me....my 4 cylinder is a alky-hog........always checking/filling the bottle......been meaning to install a cell....there was one time I ran out...... not good.....didn't hurt nothing though. Got lucky.

Addicted to 4 wheel burnouts.....

Mark

 

[DMan]

Scenario... alky kit quits spraying at 25 PSI... it kills the ignition.. motor shuts off.. you lose power steering and accessories like brakes as well..

Actually if ignition was killed but power was still on, you would still have your brakes in a TR (that is of course unless you converted to vacuum brakes)

Chalk one up for the powermonster!

 

[BoostMasterK]

Just some ideas...

Not sure how these kits react to the "low alcohol" signal, but I'm guessing it's just an idiot light?

Reason I asked, I noticed the Boost Commander has trigger inputs. I was thinking I could buffer the "low alcohol" signal to the Boost Commander to run low boost when the alky level is low. Not exactly protection from a failure, but more idiot proof.

You could also buffer the pump voltage feed as an input to the boost commander which would cover a fuse blowing or controller failure.


Mike

 

[2QUIK6]

Actually I think cutting the ignition would be a good idea. If you have vac brakes and the booster is not bad, it should hold a vac for a while, so you'd have brakes, and if you're in 25# of boost, just how soon are you going to need to make a sharp turn anyway??
Most of the 25# boost runs are goign to be at the track, its straight and there's plenty of room to stop with the emergency brake if need be.....and besides, if the motor didn't cut off and you gernaded your motor..it ain't going to be running anyway to have brakes and steering!!!

 

[John Purdom]

Actually I think cutting the ignition would be a good idea. If you have vac brakes and the booster is not bad, it should hold a vac for a while, so you'd have brakes, and if you're in 25# of boost, just how soon are you going to need to make a sharp turn anyway??
Most of the 25# boost runs are goign to be at the track, its straight and there's plenty of room to stop with the emergency brake if need be.....and besides, if the motor didn't cut off and you gernaded your motor..it ain't going to be running anyway to have brakes and steering!!!

Yep, not to mention the good chance of driving thru several quarts of your own oil. I didn't mean to ruffle anyone's feathers by asking that question. I know that both of the systems (SMC and Razors) have a great reputation for dependability. but if you can have a failsafe, why not? There are probably more people that run them out of alcohol than have pump failures. End result would still be the same, errant elephants notwithstanding...

 

[Razor]

Ok.. i'll play.

What would you suggest as the trigger for killing ignition?

In other words what conditions would have to be met, for how long, to then disable ignition at WOT. How bout part throttle? Pressure?? at what pressure?

Let see where the ideas flow.

As to the low level, bad idea.. as alcohol sloshing can trip the low level while there is still in the tank. So that one.. ehhh.. bad.

 

[2QUIK6]

Ok.. i'll play.

What would you suggest as the trigger for killing ignition?

In other words what conditions would have to be met, for how long, to then disable ignition at WOT. How bout part throttle? Pressure?? at what pressure?

I'd say, make it fairly easy..don't worry about throttle.
What's the 2 basic reasons that damage would occur?... High boost and not enough octane (which translates to alky).
So, what is high boost..lets pick a number that would be damaging if the alky quit and all we had was the pump gas and the fueling amount programmed in the chip...lets say 20#..probably would be more like 18.
Ok, at 20# boost, the MAP outputs 'x' voltage.

Then add an inline pressure switch in the alky feed line...that switch should switch on at 'y' amount of pressure in the alky line..."on" being say 5 volts.. Not sure what that "Y" amount of alky pressure should be, but I'm guessing somewhere in the neighborhood of 75psi...Iwould think at just over 20# boost the alky should be coming on pretty strong.

Solution: Cut off ignition if MAP voltage is greater than 'x' and the alky pressure switch not outputing 5 volts.

I say don't worry about TPS because >20# boost and no alky pressure is disaster no matter what the TPS is.
Also, not worrying about the filter being clogged as I would think that would be something that woudl happen gradually...and slowly producing more and more knock as the filter gets more and more clogged...not an instant thing like a pump quiting or wiring problem.

Then comes the question of how to cut off the motor without damaging it...of course you don't want to cut fuel. If you just cut off spark...at 20+# boost what would that do to the motor?? If you cut off the ECM power..what would that do?? Of course not worrying about the brakes and steering as per the above posts/comments.

 

[Razor]

Ok.. now lets work with pressure, my car at 8 PSI makes 75 PSI alky. At 20 PSI i'm flowing approx 140 PSI.

Someone elses car may be 70 PSI at 20 PSI. So what is needed is a way to monitor pressure(have a variable transducer) and track it. Then set the threshold.. but how do you set the threshold?

This would mean subjecting the car to knock to see what amount would be minimum at a certain PSI.

Then we work on how to shut things down. All the sensors on the car when killed.. kill fuel.. cuasing a lean condition. Nothing on the ecm cuts spark.. unless the ESC is interupted.. and I dont know what malady that can cuase.

Killing power to the ecm resets the computer.. so it would have to relearn. Also I would never make anything that could shut the motor down.. that type of responsibility I personally wouldnt have.

Tracking boost pressure of the MAP is easy. Tracking the pressure at a given PSI of boost..gets trickier. As the boost my rise faster than the pumps pressure in some cases.

Pressure transducers that track to 250-300 PSI get pricey.. and are methanol compatible. Thats in the works for latter this year.

 

[2QUIK6]

Ok, lets see if we can figure out the thresholds and then address the engine shut off.
Maybe hardcode or hardset the alky pressure at say a lower value...say 60psi...anyone producing over 20# of boost would at least have 60psi of alky flowing at that point I would think..so at 60 psi, the pressure switch is "on".

Ok, the logic is then, that the alky pressure switch should reach its "on" point long before you reach the boost threshold of say 20#.
Therefore, if once the boost hits 20#..if the alky switch is not on....cut things off. I'd have to think thru it, but I think that could be done with a series of relays or electronic flip flops or AND gates.
I'm also assuming that if the pump fails it would not be producing the minimum 60 psi....would that be a safe assumption?? if not all bets are off I'd think cause then you could reach the minimum threshold but still have a severely low amoutn of alky for much higher boost.



As far as cutting off engine..this thought just came to mind....tie into the ignition switch and act just as if the key was turned off in the middle of a 20+# boost run.....anyone ever turned their key off in the middle of a run before letting off the gas??

Yes, I understand not wanting to be responsible for something cutting of the engine on the street if it malfuctioned...I've had that happen before at low speed and its no fun.....I'm thinking more of a track application..maybe that could be disconnected easily so there no threat of ot malfuctioning when on the street.

 

[BoostMasterK]

Ok.. i'll play.
...As to the low level, bad idea.. as alcohol sloshing can trip the low level while there is still in the tank. So that one.. ehhh.. bad.

That sounds like a design flaw. Let us know when you have that fixed


Mike

 

[Razor]

That sounds like a design flaw. Let us know when you have that fixed


Mike

Originally contacted the engineers at GM to fix it, but they were to busy fixin the bouncing fuel guage on the 87 GN cluster.. so..

I have the engineers at NASA working on it.. be a while

 

[Robbie-87plz]

I'd be scared.....might find a tile floating around in my alchy reservoir...jk
Need some sort of internal baffling yes?

 

[BoostMasterK]

Yeah please, no o-rings, tiles, or "harmless" foam on that solution!

Mike

 

[twin 93 svt]

not that operater error, or tunning didn't cause big time engine failures, but majority of rebuilds comming through the shop, like 9 out of 10 are alchy based motors that go boom! There is no cheap way for h.p. and I'm willing to bet my car would run high tens on 93 pump gas alone.