Inliners International
Posted By: obijuan turbo 292. propane fuel. what am I in for? - 08/02/15 01:04 AM
I always find myself coming back to this board for 292 help, so I joined up. I dont think I fit the typical user here so ill get to the point. One, ive never heard of a 292 in a jeep. Two, turbo and propane usually dont get talked about together in depth. Three, I have sort of a thing for 292s.

1984 jeep cj7. primary use as a rock crawler. slow and low.
I want axle snapping torque and immediate throttle response. I also want to be have the capability to run when its on its side. Thats where the propane comes in. Propane is very simple and only takes what it wants. Impco 425 and model E. Pretty typical SBC setup.
This will be driven to work highway maybe on the weekends ~45 minute commute. th400 trans, dana 300 transfer case with 4:1 low range, 4.56 gears and 38" tires.

Propane has always been in the build plan from day one. So I built my 292 as follows.
clifford torque cam
propane pistons 30 over
194 and 150 valves.
clifford 4bbl intake and undecided headers. clifford long tubes didnt fit.


How will this motor react to the spa manifold with a small turbo charger? Not looking for 5000 rpm, but more 1000 to 3000. At 3000 I will be very close to 70MPH. Way too fast for a jeep. So I was thinking of trying a turbo off a grand national or something.

I currently run my propane on my k5 blazer with a 396. It is 14 degrees advanced with very light distibutor springs and not much changed otherwise. Like the jeep, it has very low gears but much bigger tires and probably twice as heavy. I love the propane and I cant wait to use it on the 292 turbo or not.
Am I in the right motor specs to run a turbo even without melting pistons or something haha! thank you guys for any help. It is very appreciated.


rig in question:

well how about this?

how would this motor take to turbo charging on gasoline?
It will work fine.
GN turbo will be too small for a 4.9 liter engine though.

G.N engine is a 3.8 liter.

MBHD
one concern is this, while propane is ~125-130 octane - it does not offer much in the way of cooling like methanol does. If your going to run it hard at high boost - be prepared to add a water injection system.
I remember gas stations rating propane @ 104 or 105 octane

This one rates it at 100-110.

http://www.gotpropane.com/p3.html

Never heard anyone saying it is 125-130 octane.

This web says 104 octane
http://www.usealtfuels.com/?page_id=12
Don't know.

MBHD
Rock crawling is short bursts of high rpm to pull up a climb. Often times I don't break 2k a whole weekend.

I wouldnt say I run it "hard", as most of the load is spread over the rest of the drivetrain through gear reduction. I do beat the hell out of that on a regular basis.

The gentleman above is correct about the octane level and got propane is the system I use on my other truck.

I ask about the gn turbo because of my low spooling needs. I'd like it to light up pretty soon relative to a drag car.
But I don't want to cram so much air amd be unsafe inside the cylinder at highway rpms.

On my next day available I am going to speak with cary at gotpropane. He has great customer service and I'll see if he has a preference on kit to use.
Is there a "start here" turbo and adjust as necessary? I'm not opposed to swapping turbos to get it right. Kind of like spring rates. You just gotta try em out.
Posted By: Mitch Re: turbo 292. propane fuel. what am I in for? - 08/05/15 11:41 PM
I don't know if it's worth bothering with a turbo if you don't break 2K rpm in a whole weekend. Unless you have a very undersized turbo, you wouldn't hardly be building boost most of the time. My opinion, anyways.
Posted By: 56er Re: turbo 292. propane fuel. what am I in for? - 08/16/15 08:02 PM
Propane and turbos work together just fine. You will still want a 62-1 to a S366, somewhere in there. You just spec the turbine housing a/r smaller to come in at your desired rpm. You need a slightly larger intake lobe because propane goes in as a vapor, so it displaces some air and reduces your VE by about 10%. Mitch has the right of it, though. For a rock crawler, I wouldn't really bother with the turbo.
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