Hemi GX140 build

#61
That wasn't on nitro was it? Or was it? Been following this thread since I'm the other guy with the Chrysler Hemi painted engine. I really want to hear that thing rev burning liquid horsepower. I've played with the stuff myself, mixing up my own 1/2A Texaco fuel for SAM antique model airplane contests. I run 35% in a decompressed Cox .049 reed valve engine and manage 4 to 5 minutes run time on 5 ml of fuel, in a very light 1/2A Playboy Senior. That thing is almost out of site in 5 minutes...oh wait, this it the minibike forum. Anyway, I did manage to watch all 50-some episodes of the Surfers. My wife wasn't pleased but I was thrilled. Those guys were great! As a reader of Hot Rod magazine since the early `80's I've heard bits and pieces of their story but not like that. Thank you for that link. Nice work on your engine. It's great to see folks thinking outside of the box and fabbing up their own parts. I will continue to follow this thread with much interest (and pretty much everything else you choose to post).

-Ray
 

65ShelbyClone

Well-Known Member
#62
Thanks for the kind words and I'm glad you like The Surfers series too. ;)

That wasn't on nitro was it? Or was it?
No no, I was just making sure it would run and used some heptane since it's not as stinky and persistent as gasoline. The engine needs a fuel system and has to be moved to a more secure mount before I can go snapping the throttle.
 

65ShelbyClone

Well-Known Member
#63
Also on my mind is that running nitro will require great care with the way the ECU works. The ECU handles dwell and I found some instances where it would/could fire the coil and cause kickback when the engine is just stopping. It's not like breaker points where you can smoke the coil by leaving the key on if the points are closed. In controlling spark, the ECU has a failsafe to prevent that where it will cut coil power (which fires it) if spark is not needed within a given time. If the engine has a cylinder full of fuel and has just stopped when the coil fires off some confined nitro, that's bad. I could mitigate it somewhat with full EFI by not having fuel injected below some stall RPM, but the coil fires no matter what and for now a carburetor means no cutting fuel.

Things I wouldn't have thought about in any other instance.
 

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