Bullshark

I just purchased the Accel DFI Gen 7 ECU and a universal un-terminated wire harness for my RamJet 502. I'm pitching that MEFI3 as far as I can throw it. My preference is to implement seqential injection with the Gen 7, but before I spend the jack ($$) to by the Accel dual sync distributor and an ignition control box (which I have very little room for), I want to look into coverting it's GM small cap HEI distributor to accomodate a cam sync capability.

Anyone ever done that? or know how?



Bullshark

Bullshark

ttt
Ok, where are all the tech experts when you need them
Guess all my C3 forum cronies are carb enthusiasts.

Bullshark

Jclgodale3

der uh duh what?

Z-man

Seems like it would be too much work to play around and try to convert. I'd just get the dual sync and be done with it...

Bullshark

Z-man, You would think that all the money I have blown on Project Ramjet, I should just poney up for the added parts. The engineer technocrate that I am, won't let me pay the $500+ for something so simple. The Accel dual sync distributor is just the sensors and requires an external ignition control box. (like the MSD 6) I really don't want the clutter of another box over and above the ECU. Wouldn't it be very simple to add an optical sensor plate to the GM HEI small cap distributor and sense the #1 cylinder firing position??? Seems to me, we CF C3er's go thru great effort to save a buck when it relates to mechanical stuff. I think we need to start tackling the newer technology that involves some of this state of the art electronics we see on the new vettes. Just thinking out loud

Bullshark

Bullshark

Ok Jclgodale3, It's about time for another round of mods on that beauty of yours. You need to keep up with the Jones's you know.


Bullshark

zwede

The Edelbrock pro-flo EFI comes with a kit to convert an HEI to cam-sync. See if you can find their installation instructions and maybe that will give you some ideas.

Also, I'd recommend you do some research on sequential as I've found it has miniscule benefits. You will not see any power increase and most likely no driveablity improvents either. The OEMs use it as it lowers emissions slightly (something I doubt is your #1 priority). The only time I'd see sequential as beneficial is when trying to run huge by large injectors where it helps to fire the injector once per two engine revolutions (double the pulse width).

For what we're doing you should be perfectly fine with bank-to-bank.

Twin_Turbo

How about adapting a crank trigger setup for the crank signal? you'd need to make or rework the wheel and # of magnets for the desired signal but I'd think it should be doable, nonetheless a lot of work so the dual sync dizzy might not be that expensive

What are you doing with the MEFI3??? I have a manifold I may want to try FI on but it's just a side gig so I'm not planning on dumping tons of money into it

Bullshark

Thanks Markus, I will do that. I hear you on the bank-to-bank vs sequental. I have read articles and talked to a few people who have argued both ways. I am not yet knowledgeable enough to have a strong opinion. I have been talking to a guy here in the St. Louis area that is heavy into off shore boat racing... Competition Marine. Sounds like he is in tight with the Budweiser team, and has quite an impressive shop with a engine dyno and rows of engines he has built for various customers. Some pretty impressive boats sittin in the shop also. Anyway, he tells me that sequential is well worth the effort. Essentially, it involves the individual cylinder tunning and the performance capability that provides across the engines rpm and load band. He is quick to point out that racing dosen't have your engine operating at a single wide open throttle point that bank-to-bank advocates focus on. Anyway, I plan to play around a little with this new toy and do a little experimenting. Doubt I will be able to afford the engine dyno that Competition Marine has, but he said he has done alot of these RamJet's and already has a good baseline established. I am hoping he will share it with me without asking for big $$$ All this will be a whole lot easier now that I'm pitchin that POS GM MEFI ECU.

Bullshark

Bullshark

TT, I used to be a pretty fair baseball pitcher in my younger years, but as far as I want to pitch that POS, I doubt it would make it over the pond. If you really want it and will put it to use, its yours, for shipping.

Bullshark

Twin_Turbo

Well it'll surely beat the Mechanical setup it's now so I'll gladly take it

shafrs3

How about adapting a used crank trigger assembley from ebay and use the distributor as the cam signal.

http://cgi.ebay.com/ebaymotors/MSD-C...spagenameZWDVW

Bullshark

shafrs3, Not sure i totally understand what you mean. If I incorporate the crank sense, I still have to get an external ignition contol box, correct? Unless you are suggesting running the crank pickup wires back up to the hybrid module inside the distributor? A noisy environment for long wires?? I would then have to disable all the distributor pickups except the #1 and signal condition it thru a driver to obtain a good pulse. If all that is true, implementing a seperate optical cam sync pickup seems easier???? Good thought though I just got off the phone with Performance Distributors and Electromotive inc, who are in the business of doing this sort of thing. They had no solution. Wonder if there is a product need and a chance to make some $$ out there.

Bullshark

shafrs3

I'm not real familiar with SEFI or Accel's ECU, what I'm understanding is you need two signals (Hall effect, magnetic or optical?) for your proposed setup. I'm assuming the Accel ECU controls the ignition and needs two engine position references to track cylinder positions (if this is true I don't fully understand why). I'm also assuming the ECU has two connectors to receive those signals. I just threw the out the idea as something that might be a possible solution, thinking outside the box so to speak.

As far as whether the external control box is necessary I was thinking the sensor might generate the signal that the ECU needs by itself.

73 LS-4

Bullshark,

How about I trade you my 870 Holley for your Ramjet setup and I'll be perfectly happy with it, and you'll have a dirt simple carb without any wires to mess with. Wouldn't that be the optimum solution for all Oh yea, to make things even simpler I'll swap you my M-20 muncie for that tired ol overdrive tranny you've been using

On a more serious note to possibly help you with your question. I'm guessing your 502 is a gen VI engine, in which case wouldn't it share some common traits with new production big blocks (I may be way off base with all of this but I'm just thinking out loud). In which case they would be using a DIS system with sequential injection. therefore they have to have a way of picking up #1 cylinder identification. If this is the case you can probably end up with some sort of a hybrid system using OEM components with aftermarket software. OF course this would all depend if the production blocks have a lot in common with your crate engine.


Pat Kunz

carriljc

That's essentially what sensors and distributor are used on a RamJet 350. I converted my RamJet to a 730 ECM. I just repinned the wires for the ECM and added the IAT, VSS, and O2 sensor...well, and I had to burn a new prom.

You can get a lot of info on the GM 730 ECM so that might give you a lead into what you're trying to do.