Thread: ramjet 350 problems

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Hi all. Does anyone have any technical knowledge on the ramjet 350? I have a 55 chevy with a supercharged ramjet 350 that for some reason will just decide to stop running on a couple of cylinders. All you have to do is take your foot off the throttle and goose it a couple times and its back to normal. The problem is, I'm not the builder, and the builder is out of business. Any help would be appreciated. Thanks.
Bill

What did the builder do regarding the MAP sensor when they put the supercharger on it? What brand of supercharger did they use?.....it is hard to imagine a RamJet with a supercharger.

Its got a powerdyne supercharger. I have no idea what they did about the map sensor though. I've got a buddy of mine helping me with this so hopefully we can get somewhere.

So the thing has a centrifugal supercharger feeding the throttle body of the RamJet......

Two things come to mind: first the MAP sensor. If you are running boost, you need a 2bar or 3 bar sensor instead of a normally aspirated 1bar sensor. Can you disconnect the supercharger belt and will it run? If so, does the problem go away?

The RamJet uses either a MEFI3 or a MEFI4 controller (Mercury Marine). You should be able to find out if there are mods required to run a boosted engine.....one source is Arizona Speed and Marine in Chandler, AZ. I am sure that there are a lot of others familiar with the programming of a MEFI

I do know that Arizona speed reprogrammed the computer for it to run properly with the supercharger. I will find out about the map sensor hopefully tonight.

Also. the problem with cylinders cuttin out has never happened while idling, that I know of. It has always happened while driving. Sometimes more than others.

If Az Speed and Marine did the programming, why not cal them and ask if they know anything about the problem???

I am confident that AS&M wouldnt miss the map sensor...they know what they are doing.

mike in tucson

Try colder running plugs. The blower makes a lot of heat. The stock heat range plugs won't hack it. Having to "clear" it with the throttle usually points to the plugs.

I am going to try and call AZ speed on Monday. We checked it today and there are no codes. I will ask them about the plugs. Thanks for the help so far.

Bill