How is people getting big power out of propane

Im running 425 carb mixer. It there any secrets people's doing to them to get big power.

They are throwing it away and going to gas!!!! :****:

How did I no u would say that. Seen some rig that will rip on propane... I did learn I can change the diaphram in the top of the carb. The make lean ones and rich ones

The only stinky gas you need on that rig needs to be coming from your ass after eating bad Mexican food!!

I have been to that the higher the compression the more power and the vacuum advance needs to come in quicker at a low rpm

I ran a big block and with one 425 mixer it was like it was starving for fuel. Got a dual setup 2 425 mixers into one baseplate from Buddy at alternative fuel and it made a huge difference on making the motor come alive. Just my 2 cents

ps. I have a duel 4 intake i would sale for 200 fits old school sbc heads

How much power do you need from propane?


Effin Jimmy smokes V-Notch

Why doesn't someone make a bigger mixer, seems like there is deffinately a market for it?

Elliott said:

Why doesn't someone make a bigger mixer, seems like there is deffinately a market for it?

Click to expand...

yhea :

400hp. It's a 400 .40over dart pro 1 alum heads 6" rods. 10.5/1 piston 64cc heads. Big solid cam but going to a small cam for vacuum for the propane.

Got Propane told me a single propane system is only good to around 450hp, any more would require dual mixers.

Impco makes a 1600 cfm mixer

When doing some research on this I ran across a post from Draggbody on pirate, "i constantly twist my big block to 4800... i have turned it 5500+... i use an air/fuel ratio gauge to monitor my settings and it always goes way rich when i stand on the gas hard... that tells me that it flows enough propane, i have calculated the math on cfm's and it says that the impco wont physically move enough air to rev more than 4800, but mine did... i would say that impcos cfm rating are perhaps a little conservative... here is a few 5500 rpm throttle shots, motor sounds good and it never got over 210*...edit: i run a single 425, model E, and a VFF30 lockoff..."

Also there is an OHG450x which is supposed to flow better than the 425 but from my reading is a bitch to get dialed in. Also Imco makes a model 600 which is reported to flow over 900cfm's. The downside is that it is rediculously huge in size.

Making good power on propane is like any other fuel. It is choosing the right parts for your engine and tuning it properly. A single mixer(300, 425, X450) all will supply enough fuel and air for 325-350 horsepower up to about 5000 rpm on a 350 smallblock. It will still spin up past 5000 rpm but will not make any added power. The larger the engine the lower the rpm that the engine will run out of air. Think of a single mixer like a two barrel carburetor. Dual mixers will supply enough fuel and air for 650-700 horsepower and any rpm you want to spin your engine up to. You can over 650 horsepower and still not have any wires, sensors, computers or headaches.

The larger Impco mixers are not a good choice as they are designed for very large engines(such as 1200c.i. V12) that have a huge vacuum signal for low rpm stationary operation. They would not work well on an engine that goes through a wide rpm operation. Think of it like putting a 1150 dominator on a street motor. They are also very expensive.

The photo is Tim Cantrell's rig running a 383 stroker that dynoed at 565 hp and had a killer torque curve that started around 1800 rpm. It was interesting at one of the Gray Rock XTERRA event when the weather changed and several of the guys running fuel injection were fighting driveability problems. Propane mixers are designed to be self adjusting and simple.

I have been in the conversion business for 21 years. Call me if you need help.

Buddy Gamel
Precision Sales & Service, Inc.
451 64th Place South
Birmingham, Ala. 35212

877-403-7827
205-591-2267, fax

[email protected]
[email protected]
www.alternatefuel.com
www.workhorseservice.com

I totally agree a 425 is plenty, but you need high compression. I run one on a 350 and it's amazing how much power I have out of a mostly stock engine, but it have 10:1 compression with 283 heads.

gubni said:

I totally agree a 425 is plenty, but you need high compression. I run one on a 350 and it's amazing how much power I have out of a mostly stock engine, but it have 10:1 compression with 283 heads.

Click to expand...

He's right, you are at 10.5 to 1 and you can safely go to 12.5 to 1 on pane. Shave them heads, deck the block, and don't be scared of the skinny pedal. Of course you need to make sure you're not starving the motor for fuel... busted pistons are NO fun

im runnin a 358 thats 13:1 compression with a 425...its a 520hp race motor with dart 215 angle milled heads...that impco seems to be feeding it just fine, it smokes the tires off it and breaks all kinds of parts in my smith buggy

Any ideas on what kind of power my 4.3 on pane with an ohg450 would make if I bumped compression up to 12:1.

lucasbranham said:

Any ideas on what kind of power my 4.3 on pane with an ohg450 would make if I bumped compression up to 12:1.

Click to expand...

700 horses just like everyone else!!!!