Need help with propane....

[rkcarguy]

I got a tank, hoses, vacuum shutoff, and Impco model J regulator off of a dead 4-cyl 1500cc forklift.
I'm trying to figure out how to install this on a Civic in dual fuel mode without adversly affecting the flow thru the intake and throttle body(I have electronics figured out).
The mixer on the forklift won't work because it's meant for propane only, it's airflow is too limited for gasoline operation so I'd like to not use it.
I"ve read where you have the option of simply piping it into the intake below the throttle body with properly sized pipe(spud-in jet), or mounting an adapter plate between the throttle body and air cleaner. This means is could be as simple as shoving a pipe into my intake before the throttle body, or drilling and tapping holes near each injector and running a tube to each intake runner?
I'm trying to understand if I need the mixer, or can simply inject the propane into the engine direct from the regulator/converter-as it appears to be a vacuum(diaphram) controlled supply on demand device.
???

[nemesis]

They did similar build on extreme 4x4 on spike tv, google them, and that should help you out.

[Christ]

Get a NOS plate for the Civic's TB opening, or just drill/make one. You'll have to meter the flow, though, so a flow-rate indicator and AFR gauge w/ a wideband will help, there.

The other option is just to install an injector in the plenum, just after the TB that will flow the propane into the intake tract. IIRC, it's best to have it as close to the throttle plate as you can get it, so it has maximum turbulence to evenly distribute.

Remember that for best results, you should use the vaporizer from the tow motor as well. (Thing that looks like a regulator, and coolant runs into it.)

[rkcarguy]

Christ,

The setup I got is two pieces, a VFF30 filter-vacuum lock-off, and the Model J regulator vaporizer that the coolant goes to. I was trying to figure out if it matters that the propane would be injected after the throttle body and not before like they do it on the forklifts and propane trucks.
If the regulator/vaporizer gets its "demand signal" solely from the vacuum line to the unit and has no impact on the propane feed line itself then I could could pipe it in wherever?
I was looking at drilling and tapping each intake runner, and using the push lock system of fittings to a junction block so all the hoses are the same length. The honda's log style manifold will not distribute fuel evenly from the throttle body area I am afraid. Then I'd simply use a ball valve on it along with the wideband to get the AFR where I want it.
Also availiable are different springs for the model J, the stock 1.5" vacuum, and optional .5" and .2" vacuum. I have no clue which one would be best.

The cool part is, the engine is out right now so I want to do all this on the bottom of the intake and you won't be able to tell it's there

I have a friend that chips and tunes honda ECU's, and after some research he found that the guys that have been drag racing with carbs(duals or quad carbs-remove EFI) have been retaining the ECU for timing and knock detection and just setting the injector values to zero...so we think that we can use a multi-map chip and make the whole thing switch on the fly...and be able to add hotter timing when on propane.
One double throw quadrouple pull toggle will change ECU to the propane map, kill the fuel pump, and activate a yet-to-be found vacuum solenoid to engage the vacuum fuel lock.

[Christ]

The springs are a tuning issue that you'll have to figure out for yourself, they're similar to jetting in carbs.

As long as the fuel control gets it's signal from vacuum, it will not matter where you put the fuel input. You could (in theory) replace the injector ports with propane, if you were so inclined. Instead, you probably (since you mentioned piping the bottom of the intake) would want to drill and tap your injector fittings in at approx a 35* angle from the intake runner's floor. Any steeper than that, and you could be limiting fuel intake because of reversion. You want to keep the arc between the injector nozzle and the intake valve as low and long as possible so that fuel doesn't pool. (Or, in this case, create pockets.)

Ideally, any fuel jetted via injectors should actually be sprayed almost directly at the intake valve, but since propane is already vaporized, you should be OK moving the injector nozzles back about 4" from the intake ports and letting the propane and air mix on the way down the runner.

[rkcarguy]

So with the angle of the nozzles, you are implying that I tilt them into the flow such that it draws a vacuum on the orifices?
Could I insert them 90* to the flow but then drill the holes into the downstream side of the nozzles and clock them properly when inserting?

[Christ]

Yep, but think of the cross section you'd be blocking when doing that. You'd be seriously inhibiting flow.

If you can weld aluminum, it's probably better to just weld some bungs on at ~35*.

Also, I indicated the wrong plane to be working from - you can have them at 35* to the vertical plane (the intake mounting surface), pointing at the engine. Steeper angles are better, though, to lessen the arc that the fuel takes between the injector nozzle and intake valve.

To really get the setup done nicely, you could put the injectors in at nearly 90* to the intake surface by drilling/tapping the lines into the curve in the intake pipes, just after the plenum.

PS - you can use a brake line with air tool mufflers on them instead of making actual injectors for the setup. It's called a "bleed feed", where the same vacuum that turns on the fuel sucks it from the lines as well.

You have to drill the manifold out a little larger, and put a fitting in it that you can fit the air tool muffler in and still be able to thread the fitting into the manifold, then screw the (custom bent) brake line/fuel line fitting into the bushing that you made.

[rkcarguy]

By my calc's I think a 3/16" feed line per cylinder will be adequate. A guy that converted a 2.2L S-10 did a single 3/8 line and had to restrict it with a ball valve, another with a VW used just drilled his fitting till it ran right and it ended up being just under 1/4".
I don't think a 3/16" tube extending 3/4" into each runner is going to hurt flow much. I won't have a problem with HP I am already swapped to a 9.4:1 compression 2.0 liter B-series.

[Christ]

It won't hurt low-RPM flow too much, but it will bother enough to potentially cause detonation at higher RPM/loads.

You're right about power, though. You'll likely have enough torque to keep longer gears and not have too much trouble on the low-end. Keep in mind that with propane, you'll likely lose some of your power. You'll also need to switch the ECU off so that it doesn't go nuts when you turn on the propane, so you'll need to figure out your ignition system as well.

[rkcarguy]

The car I'm using is a 1993 Civic. It's obd-1 and with it chipped, the 02 can be turned off, idle air control solenoid can be adjusted or turned off, fuel values can be set or tuned to zero...there is alot that can be done here.
We'll be merely making a copy of the original oem program, zeroing out the fuel values, turning off the O2 sensor feedback(it will read but not adjust), and ramp timing. In gasoline mode everything will function as normal, no check engine lights, and will pass an diagnostics check via the check plug...however we don't have emissions here yet..
My friend that does the tuning can do up to 3 "maps" per chip, turbo, nitrous, VTEC, intake air butterfly's, propane injection(used before intercooler in boosted applications)...it's all adjustable and tuneable....even a ballet parking mode that only allows 20% throttle and 3000rpm rev limit