Advice needed for SMC ALKY Injection Install,previous users?

S

smeagol

Active member
I'm not sold on propane yet. The argument is that it is a gas that will displace oxygen, and oxygen is the hardest thing to get in your combustion chamber (hence ported heads/camshafts/more boost etc etc).

I was looking into propane a year ago or so, and that was the same story I was told by many knowledgeable people. Not saying that's the end all conclusion for me, but I don't like being a pioneer. Pioneer implies a steep learning curve, which implies lots of broken parts :wink: I'd rather work with proven technologies...
 
J

JoeLutz

New member
Does the SMC kit use a line from the intake to pressurize the water tank? the reason I'm asking is if not, then the pump is having to move the fluid against a pressure gradient, from atmospheric to say 15psi+ of boost in the intake. With fixed power pump, this means that the water/alky flow is going to decrease as a function of increasing pressure gradient due to increasing boost. In other words, the fluid is going to be flowing the most when boost just reaches the turn on level for the pump, then as boost continues to increase, the flow of water/alky will decrease because the pump is having to overcome an increasing pressure gradient, while we actually need the flow to be increasing. Just some food for thought.
 
Daron

Daron

Active member
Some SMC alky kit hints:

The add on Capacitor is almost garaunteed to be needed. I tried several different values and settled on 220uF, as it seemed to clean up the power feed the best. After talking with Steve, it would seem that the way his system pulses the ground to the pump may be the reason for the minor electrical gremlins we see when using it in our trucks.

Powering the SMC with a separate relay, where the feed to the relay is aquired from the power point on the firewall (as opposed to the fuse block), seems to work the best for my truck. I have fought transient electrical noise, which seems to have caused some serious false knock, was mostly eliminated when I used a relay system to get power from the leads on the firewall.

Also, remember that too much alky will cause the truck to begin to bog, or misfire. This misfiring WILL cause you to see knock counts, and the ecm will start ratcheting up with the knock retard. This is a very important point, because you can confuse the results of this (knock retard) as eletrical noise causing the retard instead of its true cause.
As I was learning how to tune my alky, I noticed that more fuel would reduce this mis-firing, but plug checks showed it was way rich. That made sense, because generally a rich afr is easier to fire. With my MSD ignition, I noticed that a rich AFR, and wide gaps, I could use more alky. However, the performance wasnt up to par.
So, after getting rid of the false knock with the relay and capacitors, I could clearly see where the misfires were.
So, I tuned the trucks fuel with no alky, got the plugs looking good. Then began the addition of alky. It would break up at 18 psi with anything over half on the pump speed knob. Instead of adding fuel this time, I closed the plug gaps up to .030 and all is well. Not being fooled by false knock helps tremendously here.
Now its time to try to lean it out some more and toss a bit more alky at it....

So, don't be discouraged if the kit isnt a plug and play affair, we can likely get it working well for your application.
 
Daron

Daron

Active member
JoeLutz said:
Daron,
What power (watts) rating capacitor did you use?
TIA
Click to expand...

Hey Joe,
I bought a number of 220uF - 25volt capacitors. Those numbers should get you what you need from Radio Shack.
Take care,
 
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