propane for high performance 3

[ktbundy]

I'm about to convert my car over to propane using standard Impco parts. I have a 360 Mopar engine that will be running 11.5 to 1 compression. The heads have stainless valves, bronze guides and hardened seats. Everything internally is pretty much new, as is the machining. I have chosen a Weiand 2x4 tunnel ram, and will be using 2 425 mixers, 2 vaporizors(model E), and 2 fuel lock offs. Are there any additional parts that would optimize this set-up? And I was thinking of fabricating my own mixer adapters and removing the current top plenum of the intake(to help a bit with hood scoop issues. Is this going to cause any problems if there is no front to back balance tube between the intake runners, like the top plenum provides? Thanks in advance.
Tom

 

[turkeyokato]

Hi Pat, Yes that engine is mine. Here are some links to some photos.

http://p206.ezboard.com/fmoparmarketfrm11.showMessageRange?topicID=116.topic&start=1&stop=20

http://www.hemiperformance.com.au/

My engine is the black one with stainless inlet runners.
Go to "whats new" then "Photographs" on the Hemi perf site for shots of the block.
I will send the file when I next get a minute.
Did you win again? I have been away along time and not been up to speed.
Pine tree meads said it best about the current state of our teams with "there are too many mirrors in the changing rooms"
Cheers,
Joe.

 

[franzh]

Of general interest, when retarding the ignition to prevent detonation, your exhaust temps climb thusly increasing boost, which increases inlet pressure until the wastegate pops. Its a wild circle.
You may have luck playing with air to fuel ratios when at hard boost. I have leaned the fuel mixture from L=1 to L=1.4 at 20 psig boost, reducing exhaust temps to 900 Deg F.
By the way, VERY VERY NICE engine! Liquid injection has not caught on here in the states, primarily due to the injection pressures. 125 psig is about 1/4 the amount seen in a typical liquid injector (propane saturation pressure + engine absorbed heat + added heat from road and radiation) I have seem pressures in excess of 400 psig! Add in one Texas day of 90 Degrees, plus road absorbed heat, and your tank temperature can reach 125 degrees F. That equates to 250 psig tank pressure. Liquid injection works by circulating propane through the injectors to flush the partially vaporized propane and returns it back to the tank. Usually, dual fuel pumps are used, one for maintaining a circulating pressure, the other for purging. We then add about 50 psig above the saturation pressure to keep the propane in liquid phase (you may have seen that name in marketing material).
Its not as simple as you may think. Supplying fuel for 500 bhp is no problem, but keeping it in liquid state is. One glug of vapor at an injector and its 270 times leaner than it was. Toss in that the fuel mapping program must operate at 270 times more precise/shorter pulse width profiles, and may injectors cannot operate that fast with an injector pressure that high.
Franz

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[turkeyokato]

Thanks for the kind comments. Excellent points you make and fantastic claims they are making to me. I will pursue their claims and get to the bottom of it.
Maybe they have cracked it.
Im gonna find out and let you know.
Thanks very much for your time.
Have a great new year everyone.
Joe.