emccomas

JF IN MI is the person that did that. He is a participant in this thread.

emccomas

I understand the concerns that many of you have expressed.

One of the things that we rocket scientists don't do is say something "can't" be done. I know most of you are not saying that, but....

I remembered telling someone recently that "given enough time and money, I could build a toaster that would fly to the moon, but I might be better off starting without the toaster"

The point being that converting an original Rochester FI system to EFI and still maintaining the external appearance of the original system is "doable", but it may not be cost effective to do so.

OK, so my "Mission Statement" is something like this:

Convert an original 1963-1965 Rochester Fuel Injection system to Electronic Fuel Injection while maintaining an external appearance as close to original as is feasible.

I am not really interested in installing an original Rochester FI system, that is not the goal. I want a resto-mod Rochester FI system, or a Rochester FI system that is upgraded with modern technology. So, my goal is the look of an original Rochester FI system with the reliability and functionality of an EFI system.

I know the conversion is possible, as it has been done many times, and I might end up there. But I want to see how close I can get to original looking while doing so.

Grampy

If you want to enhance the illusion, with some extra work you have the option to use the Rochester air meter assy as your throttle body. EFI throttle bodies have the throttle plate plus provision for a TPS and IAC mounting. To convert the RP part you won't need the venturi diffuser/choke except for the outer ring to attach to the air cleaner tubing. The venturi and choke bits that sit in the flow stream are not needed in an EFI system and restrict the air flow. You would need to devise a linkage to the throttle position sensor - maybe hide it in the cockpit by the throttle pedal. The TPS is calibrated as part of the initial setup so it knows 0-100% travel. EFI uses a idle air control valve which has to be plumbed in behind the throttle plate. You would need to make an IAC mount. The air feed from the IAC can connect to the existing nozzle vent tube on the air meter.

wmf62

please be careful not to mess up your next-to-unobtanium parts in your quest...

Bill

wmf62

I don't THINK JF did the TBI route, I believe his was the stealth 'conventional EFI' route. SOMEONE simply bolted a TBI to the side of the doghouse
Bill

as is getting to be usual, I was wrong, it was JF

Bill

Loren Smith

Here's the thread:

https://www.corvetteforum.com/forums...-followup.html

https://www.corvetteforum.com/forums...ts-beware.html

Everyone's taste is different, but if I went to the trouble to build a Rochester EFI, I would want to show off the gadgetry just a little bit. I.e. have just a little "mod" to go with that "resto."

JF in MI

OK, here is the situation as I see it. I went with the TBI 'on the dog house', as it were, because it has "known" components (the size and flow of the throttle plates) to the computer programming. The issue is matching the approximate airflow, through the range, to the injector output. The computer relies on this approximation during open loop to keep the engine running until it warms up enough to go closed loop where the O2 sensor takes over. A throttle position sensor does just that; tells the computer the position, however if that airflow curve isn't in the program in some form of algorithm, or such, it has no idea what fuel to deliver. This is why you may be able (or maybe not) to have the same computer for a 4 cylinder and a V8 but different prom chips. Having a mass airflow sensor in the system might help but, once again, that is a sizable chunk of component to try and hide in the overall system.

emccomas

Bill;

What parts are you referring to? I assume you mean the Rochester FI parts. The only part I envision being modified at this point is the plenum, and I am planning on using the plenum that I have that has welded legs (assuming I can get it to look 1/2 way decent).

I know welded plenums (and other FI parts) don't look quite right when re-finished for an original look, but I am not sure what actually happens to the parts. Does anyone know what happens to welded FI parts over time in terms of appearance.

I actually have another sort of secret goal. I want the base adapter (manifold) to look / remain absolutely stock. I have a second plenum that does not have any welded parts. I want to retain the possibility of removing the EFI conversion, and installing a factory Rochester FI system.

To that end, I am keeping my eyes open for an appropriate fuel meter and a distributor.

I could potentially swap out the plenum and distributor from the EFI conversion for an original style plenum and distributor.

I know, seems silly to do both, but the original FI is just an option.

And yes, I know this impacts the fuel delivery system as well. Haven't thought that one out yet.

Again, long term project.

wmf62

Ed
yes, I meant the Rochester parts

I know of no reason to have to modify the adapter plate, all conversion items should be involved/contained on/in the plenum. personally, I have never been a fan of drilling and inserting a PCV in the plate, I prefer pulling out of the valve covers and/or road draft or filler tube.

welded parts will almost always show the repaired area forever with maybe a patina change unless they are 'reskinned'. there is a guy named Jerry MacNeish who can repair/refinish aluminum parts to look like they were never damaged

AND, I have my complete original Rochester in a box just in case there is a miracle cure for fuel perc and i want to go back to FI. (I don't foresee that happening tho…)

Bill

Grampy

The plenum is a nasty piece to weld repair but it can be done. Before rocket building was moved to Huntsville we did it out here and had a large skilled workforce. My golf buddy was a welding engineer and Pres of the LA section of the American Welding Society. In about 1980 he and his welding tech spent most of a Saturday fixing 2 small cracks in the legs of my plenum. We metal finished the repair area at the time of the repair.

The picture shows the repaired area. It was taken about 30 years after the repair when I was doing the EFI conversion. I don't think you can see anything of the repair.

wmf62

lol.... I just had cataract surgery, I can see the weld. BUT, it is a great repair job; kinda makes me wonder what kind of abuse it takes to break a plenum

Bill

jim lockwood

Piece of cake..... just crank down on the nuts which hold the plenum to the adapter plate.

Jim

wmf62

shouldn't happen... but apparently it does...
Bill

vettsplit 63

I like the old school/ new look of this unit that I am having done for a 395" engine I am putting in my 63. Best of both worlds.

wmf62

Bill

mexicruiser

wesmigletz

What are the details of that FI set-up?

Fordracer9

I was thinking the same thing. Or possibly go Direct Injection from under the manifold?