I've never done it personally, but I'd think you'd have to run boost through the float bowls too to pressurize them. Otherwise once the turbo spools up, wouldn't the boost pressure keep the fuel from flowing out of the jets? I'm not sure though, just a thought. I'd like to know more because I'm in the process of gathering parts to do the MJL crank-fired ignition that cygnus x-1 did on his, then eventually I want to turbo mine ('87 DX).... :Rock:I imagine that is a pretty difficult task. Tuning a carbed turbo must be tedious.
MegaJolt Lite. It's based on the Ford EDIS 4 crank-fired ignition using parts from 91-96 Escorts/Tracers with the 1.9L. You use the trigger wheel from the harmonic balancer, the corresponding sensor, the EDIS 4 module, and the coil pack from the Escort/Tracer with the MegaJolt Lite module and eliminate the distributor. I think cygnus even did a writeup on it. As far as which is more efficient/easier to tune, that I don't know. I've never used the MSD systems or the MegaJolt system before. Hey cygnus, if you're reading this, feel free to chime in and offer your $.02...MJL crank-fired ignition ? do tell. I am in the process of turboing my car (87si) and i am using a msd btm for timing, is that more effcient?
And fullthrottle_man, sweet to hear you're going EDIS, me too. I already put together my MJL and soon as spring rolls around, cygnus will be helping me out with it. Can't waitIf you want to do a blow through turbo setup, take notes from those toyota corolla guys running their 1970's round backs with turbocharged 3TC engines.
Yeah, there isn't too much information regarding blow-through weber turbo systems on the internet. I was lucky enough to hook up with a guy in Hawaii that built some fast corolla's. At the time he had a corolla that broke into the 9's with a blow through setup. He was running 30+ lbs of boost through a set of 45 DCOE's.
There is no real trick with boosting a weber setup except for these few key components:
1. Make sure to pressurize the fuel bowl of the carburator. This will ensure that fuel will still flow out of the jets into the intake runner and not the otherway around.
2. Be sure to use plastic floats. Those old brass floats will crush under boost and will take on fuel eventually flooding the carb/engine.
3. You must use a rising rate fuel regulator. It sounds odd to run more than 4 psi of fuel pressure through the carbs but it is needed to compensate for boost pressure.
In the 1990s Ford used an Electronic Distributor-less Ignition System (EDIS) on some of their cars. Because it's a fairly simple and reliable system (and performs well too) it's become popular as a retro fit for older cars. Instead of running a standard distributor from the cam it has an ignition module that senses pulses from a toothed wheel mounted to the crank pulley. Using the crank position it can control ignition timing based on whatever the ECU tells it to do. So some smart people created a standalone controller (the Megajolt) that uses manifold pressure (vacuum) and the tach signal from the EDIS ignition module to tell the ignition module what ignition timing should be. It's essentially an ignition only ECU.MJL crank-fired ignition ? do tell. I am in the process of turboing my car (87si) and i am using a msd btm for timing, is that more effcient?