Thinking About Installing Alcohol Injection?

[kuku]

I am slowly collecting all the parts needed to install the DIY kit. I have been doing a lot of reading and want to make sure I understand everything before install. I do have one question, how do you control the turn on point? The DIY website uses a pressure switch from NOS but I have also read about the Hobbs switch at Allied Electronics. The pressure switch mentioned turns on at 15psi and I would like to be able to adjust mine from anywhere between 10-15psi. How do I go about doing that?

Thanks,

Clay

 

[gofstbuick]

The NOS pressure switch is that same as an allied unit except if you order it from the place Red Regal T says to, its cheaper. The 15psi NOS switch has some adjustment. I used a radiator pressure tester (to create pressure at the switch) and removed the cap adapter (capped one side of the tee on my switch assembly and hooked the other side to the pressure tester). I then removed the rubber cap and using and allen wrench, turned approx 3 turns counter clockwise. I used a ohm meter on the two pins of the NOS switch. I fine tuned the switch to make continuity at 11psi. Hope this is understandable as it's late.

 

[Red Regal T]

Forget about that pressure switch on Steve Monroe's site. Steve put up that info a long time ago. I'm not sure it's available and it's really not reliable. When I first installed my DIY kit, I used that switch. It only lasted about two weeks. I then installed a hobbs switch. Been using the same one for almost four years. I was told that $15 switch from allied was adjustable by a guy who had purchased it. At any rate, use a hobbs switch. You may be able to get one at NAPA, but may cost more. You need a hobbs switch that will adjust from 10 to 15 lbs. You turn the pressure adjustment up by turning the allen wrench clockwise.

 

[gofstbuick]

John,
Steve may show the GM switch in his picture, but he recommends the NOS pressure switch in the written illustration. It is the same as the Hobbs switch you recommend, but more expensive. Unfortunately, I already purchased the NOS switch from Summit and it would probably cost more to send it back, plus it was already in my possession. If my NOS switch ever goes bad, I'll order from allied the next time (as it was half the price of the NOS switch), since it 's the same thing.

 

[Red Regal T]

Seems you can forget about the cheap switch from allied electric. They add on another $15 to find it and ship it.

 

['86T]

John,
Allied electric's website states the minimum order amount to waive the additional ridiculous $9 handling fee is $25 plus you still have to pay for shipping. Therefore, if only one switch is purchased then it is sort of expensive for the Hobbs switch. Seems like the best way to get a deal is to maybe do a group purchase from allied. That way the $9 handling fee will be waived. Too bad JeffG's post didn't mention the handling fee.

Steve

 

[Red Regal T]

Well Steve, that's not TOO bad. One could always buy two of the switches. Either keep the extra one in reserve or sell it to someone putting a kit together.

 

[LUISBOOST]

How about Xylene in the tank??

How about Xylene in the tank??, maybe with distilladed water??

 

[Red Regal T]

Xylene may be damaging to pump, lines, and seals. Also, won't mix with water. Methanol acts as a fuel, mixes with water, and cools the combustion chambers.

 

['86T]

Originally posted by Red Regal T
Well Steve, that's not TOO bad. One could always buy two of the switches. Either keep the extra one in reserve or sell it to someone putting a kit together.

John,

Funny you said that because that is exactly what I did a few days ago. I have two on order. I was going to go and just get one from Napa but it listed it as Napa's Balkamp brand. Probably would work fine but I figured I'll just get a true pressure switch made by Hobbs in case Napa's is a different brand.


Steve

 

[Red Regal T]

Originally posted by '86T
John,

Funny you said that because that is exactly what I did a few days ago. I have two on order. I was going to go and just get one from Napa but it listed it as Napa's Balkamp brand. Probably would work fine but I figured I'll just get a true pressure switch made by Hobbs in case Napa's is a different brand.


Steve

Steve, let us know about the switches when they arrive. tia

 

[gofstbuick]

Originally posted by gofstbuick
Your warning light system should include the following: 2 LED lights (with built-in resistors, my preference), a fuse holder (5 amp blade, I prefer), connectors, wire (different colors) and solder. You can wire it accordingly. Start with the low alky warning first, connect positive source to one wire of the LED (fuse in between), connect LED black wire to one pole of the level guage and the other pole to ground. When the level drops to complete the circuit it completes ground and turns the warning light on. Now for the Alky on light, use the same positive source for the other LED lamp (you will only be using one fuse for both lamps and the same power source for both lamps). My pressure switch (is between the ground circuit of the relay) completes ground to activate the relay that powers my alky motor. I connected the black wire of the LED to the ground circuit relay wire closest to the relay. When the pressure switch sees the correct pressure (that energizes the relay that turns the alky motor on), the ground circuit is completed to turn the motor on and turn the alky on light on. For you momentary switch (to manually energize the alky motor) connect a wire on the same side of the relay ground as you did for the black alky-on LED and connect it to one side of the switch, the other side of the switch goes to ground. When you push the momentary button, the ground circuit to the relay is completed (bypassing the pressure switch) and the enerzied relay turns the alky pump on and additionally the alky on warning light. I really don't like to bring battery positive in to the cockpit, and would much rather bring wires into the cockpit that completes ground circuits. The power source for the LED come off a ignition pin on the fuse block (an existing B+ or Ignition+ source). I use solderless connectors with built in heat shrink (GM types, at relay and float guage) all other wires are soldered and heat shrinked. No pictures, but draw your wiring diagram out on a piece of paper and remember that electricity basically travels in a circle.

I revived this thread, because I made a mistake on wiring the circuit to the Power Injection light. As Razor suggested, you should get the + signal from the feed leading to the alky pump (to one wire of the bulb) and complete the ground circuit after the ground lead of the pressure switch (to the other wire of the bulb). It also lets you know that the alky motor is energized and not just the relay.

I made the mistake of wiring power to the bulb and allowing the pressure switch ground to complete the other end of the bulb circuit. This caused a voltage bleed into the ground circuit of the relay. Since I triggered the system using the fuel pump prime lead (gray wire as suggested by Steve Monroe), it caused my fuel pump to run constant with the key on engine off.

 

[Razor]

Glad I made a difference

Yup..wire the PI light bulb across the pump +,- terminals.

No confusion