Chev Project

Greybeard · 02-22-2001, 12:02 AM

Hey Guys,

It's been a while since I've posted here, and now that I've got your attention I'll get to my question.

I picked up a 57 Corvette FI intake manifold and doghouse which I plan to convert to EFI. The people on this board seem to have a lot better grasp of what you can do with EFI than any other group. As I'm starting from scratch, I figured I'd use a known set-up that uses of the shelf parts.

I'd like to run some cam, and am wondering how far you can go with speed/density systems, or should I go mass airflow. Advertizing in the aftermarket would leave one to believe a speed/density unit can do anything, but I'm not asking for hype, just a good solid system I can depend on. This'll end up on a 302 non-Ford, installed in my ol' Shoebox I got in '62.

So guys, if you are starting from scratch, don't have to pass any sniffer, what kind of system would you start with?

84_GT350 · 02-22-2001, 12:53 AM

Well..that's quite an intake. What you suggest isn't impossible, but it'll be a lot of work. Most aftermarket (I'm hesitant to say all since new stuff comes out every other day) EFI processors are speed/density but they are far superior to Ford's units. They are speed/density but they are fully tuneable. With some know-how and some time your car could run better than with Ford's mass air system. It's all a matter of finding out where to set the timing curves, fuel curves, etc. Good luck man. Once it's together I'd like some pictures.

------------------
1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s

Chevyguy · 02-22-2001, 09:23 AM

That is going to be one heck of a project. I assume you are looking for the nostalgia impact of the vette FI system. Is the old ramjet system totally shot??? if not that setup is worth some serious bucks.

I imagine you will need to fabricate fuel rails and drill injector bosses into the manifold. You would need to retrofit a throttle body on top of the manifold, or at the very least somehow fit the ramjet throttle blade with a throttle position sensor. Edelbrock sells a TBI to EFI conversion kit for Chevy trucks that you could remove from the supplied manifold and adapt to the ramjet manifold.

Since that project will be an enoumous undertaking and will require serious fabrication skills perhaps you could consider another method. The new GM ramjet 350 is similar in appearence to the old 57 system you have. and supposedly this ramjet system found in the GMPP crate motor is or will be available as a stand alone system from either GMPP or possibly Arizona speed and marine

The beauty of that system is it was developed as a stand alone marine system, the computer module actually is mounted in the intake somewhere, just need to hook up the 12v power and set up a FI fuel system.

------------------
Frank W
90 5.0 LX coupe Stone stock soon to be daily driver
74 Chevy Laguna Type S-3 305 apart in garage, getting a 454 to put next to it
www.chevellepages.com/folingo

MiracleMax · 02-22-2001, 11:10 AM

Hey didn't somebody develop a conversion for the old chevy mech. fI system? Or at least a look alike (not counting the Ramjet setup released currently by GM) setup. Maybe I had seen somthing in Hotrod or Chevy Hi-Performance at one time?

Anyways, I'll agree with the rest a good aftermarket speed density system is hard to beat. Both from a hardware point and the fact that you don't have to hang a clumsy MAF some place.

Greybeard · 02-22-2001, 10:54 PM

Thanks for the replys,

I bought the manifold and doghouse without any of the other pieces. The doghouse had it's tag missing, and someone had pollished it, reducing it's value to where it became a very good suspect for a conversion. I've got a 5.3 Vortec throttle body and have mocked up in wood an adapter that will hang it where the original airmeter was. With an OEM ECU, My plan A is to thread the injectors so I can screw them into the manifold. A good friend came up with an idea how to use individual lines rather than a fuel rail. His idea will require some delicate machining and fabricating on the fuel line and connection. The rest is just standard injection wiring and plumbing.

I asked for your opinion because I'm concerned about being stranded somewhere with an ECU failure, and not having the ability to walk into a dealer and getting "next day" service. The reliability of the Ford, or other, is far superior to some of the aftermarket systems.

Plan B: If I settle on using a fully adjustable ECU, I'll mock up a fuel meter using large flow throttle body units installed into a fuel distribution block. This will allow for lines and nozzles like the original had. I don't see that having back pressure on the throttle body will actually create any problem in the mechanics of the injector, and perhaps the adjustability available in the aftermarket ECU will allow me to overcome a few shortcomings that I see. If it doesn't work, back to plan A.

Greybeard · 02-23-2001, 09:16 PM

The decision was made today. I'll use an aftermarket ECU.

I picked up a "spider" from a 4.3 Vortec V6 today, and have set into motion designing my "fuel meter". The 4.3 had a throttle body type meter setting inside the manifold. It metered fuel into a spider with lines running into the individual runners. At the end of the line was a "poppet" valve. They ran on about sixty lbs of fuel pressure. The fuel pressure reg was within the manifold as well. I'll make a new "spider" that will have two fuel meters instead of the one, and eight lines. If an adjustable aftermarket fuel pressure regulator isn't available to 60lbs, I'll figure out how to use Mr. Goodwrench's unit. The "poppet valves" are the only real challenge I see now, but tomorrow I'll see how they are made, and if I can use them.

I'm kinda excited about this thing.

Wishing all a GREAT weekend!!

n2ojunkie · 02-24-2001, 04:42 AM

thats a lot of work on a system that has an high failure rate. the spider system that your are talking about has a problem with the gas carbonizing in the poppet valves and causing them to stick. this happens when ever the vehical with the system sits for about a week or longer. also the regulators have a high failure rate. gm has put a 100k mile 10year warnte extension on those units. so i would recomend staying away from thoes. i dont think that a injector has material that can be threaded on it. you really need to sandwitch it togher. now you dont need to make rails. just make a sandwitch tab of some kind to hold each injector that will also retain your fuel lines on the injectos. then all you have to do is run the lines to a distrubtion block and fuel press reg. painless wireing makes a gm harness and a ford harness that you can use to wire up either brands fi systems on your car. so you can get factory reliablity. then you would want to get a chip burnt for the custom aspects of your motor. good luck.

02-22-2001, 12:02 AM	#1
Greybeard Registered Member Join Date: Jun 1999 Location: Port Angeles, WA Posts: 118	Chev Project Hey Guys, It's been a while since I've posted here, and now that I've got your attention I'll get to my question. I picked up a 57 Corvette FI intake manifold and doghouse which I plan to convert to EFI. The people on this board seem to have a lot better grasp of what you can do with EFI than any other group. As I'm starting from scratch, I figured I'd use a known set-up that uses of the shelf parts. I'd like to run some cam, and am wondering how far you can go with speed/density systems, or should I go mass airflow. Advertizing in the aftermarket would leave one to believe a speed/density unit can do anything, but I'm not asking for hype, just a good solid system I can depend on. This'll end up on a 302 non-Ford, installed in my ol' Shoebox I got in '62. So guys, if you are starting from scratch, don't have to pass any sniffer, what kind of system would you start with?

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02-22-2001, 12:53 AM	#2
84_GT350 Registered Member Join Date: Apr 1999 Location: Overland Park, KS, USA Posts: 1,631	Well..that's quite an intake. What you suggest isn't impossible, but it'll be a lot of work. Most aftermarket (I'm hesitant to say all since new stuff comes out every other day) EFI processors are speed/density but they are far superior to Ford's units. They are speed/density but they are fully tuneable. With some know-how and some time your car could run better than with Ford's mass air system. It's all a matter of finding out where to set the timing curves, fuel curves, etc. Good luck man. Once it's together I'd like some pictures. ------------------ 1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s

02-22-2001, 09:23 AM	#3
Chevyguy Backyard Mechanic/Chemist Join Date: Feb 2001 Location: Acton MA USA Posts: 435	That is going to be one heck of a project. I assume you are looking for the nostalgia impact of the vette FI system. Is the old ramjet system totally shot??? if not that setup is worth some serious bucks. I imagine you will need to fabricate fuel rails and drill injector bosses into the manifold. You would need to retrofit a throttle body on top of the manifold, or at the very least somehow fit the ramjet throttle blade with a throttle position sensor. Edelbrock sells a TBI to EFI conversion kit for Chevy trucks that you could remove from the supplied manifold and adapt to the ramjet manifold. Since that project will be an enoumous undertaking and will require serious fabrication skills perhaps you could consider another method. The new GM ramjet 350 is similar in appearence to the old 57 system you have. and supposedly this ramjet system found in the GMPP crate motor is or will be available as a stand alone system from either GMPP or possibly Arizona speed and marine The beauty of that system is it was developed as a stand alone marine system, the computer module actually is mounted in the intake somewhere, just need to hook up the 12v power and set up a FI fuel system. ------------------ Frank W 90 5.0 LX coupe Stone stock soon to be daily driver 74 Chevy Laguna Type S-3 305 apart in garage, getting a 454 to put next to it www.chevellepages.com/folingo

02-22-2001, 11:10 AM	#4
MiracleMax Registered Member Join Date: Apr 1999 Location: Hayes, Va, USA Posts: 798	Hey didn't somebody develop a conversion for the old chevy mech. fI system? Or at least a look alike (not counting the Ramjet setup released currently by GM) setup. Maybe I had seen somthing in Hotrod or Chevy Hi-Performance at one time? Anyways, I'll agree with the rest a good aftermarket speed density system is hard to beat. Both from a hardware point and the fact that you don't have to hang a clumsy MAF some place.

02-22-2001, 10:54 PM	#5
Greybeard Registered Member Join Date: Jun 1999 Location: Port Angeles, WA Posts: 118	Thanks for the replys, I bought the manifold and doghouse without any of the other pieces. The doghouse had it's tag missing, and someone had pollished it, reducing it's value to where it became a very good suspect for a conversion. I've got a 5.3 Vortec throttle body and have mocked up in wood an adapter that will hang it where the original airmeter was. With an OEM ECU, My plan A is to thread the injectors so I can screw them into the manifold. A good friend came up with an idea how to use individual lines rather than a fuel rail. His idea will require some delicate machining and fabricating on the fuel line and connection. The rest is just standard injection wiring and plumbing. I asked for your opinion because I'm concerned about being stranded somewhere with an ECU failure, and not having the ability to walk into a dealer and getting "next day" service. The reliability of the Ford, or other, is far superior to some of the aftermarket systems. Plan B: If I settle on using a fully adjustable ECU, I'll mock up a fuel meter using large flow throttle body units installed into a fuel distribution block. This will allow for lines and nozzles like the original had. I don't see that having back pressure on the throttle body will actually create any problem in the mechanics of the injector, and perhaps the adjustability available in the aftermarket ECU will allow me to overcome a few shortcomings that I see. If it doesn't work, back to plan A.

02-23-2001, 09:16 PM	#6
Greybeard Registered Member Join Date: Jun 1999 Location: Port Angeles, WA Posts: 118	The decision was made today. I'll use an aftermarket ECU. I picked up a "spider" from a 4.3 Vortec V6 today, and have set into motion designing my "fuel meter". The 4.3 had a throttle body type meter setting inside the manifold. It metered fuel into a spider with lines running into the individual runners. At the end of the line was a "poppet" valve. They ran on about sixty lbs of fuel pressure. The fuel pressure reg was within the manifold as well. I'll make a new "spider" that will have two fuel meters instead of the one, and eight lines. If an adjustable aftermarket fuel pressure regulator isn't available to 60lbs, I'll figure out how to use Mr. Goodwrench's unit. The "poppet valves" are the only real challenge I see now, but tomorrow I'll see how they are made, and if I can use them. I'm kinda excited about this thing. Wishing all a GREAT weekend!!

02-24-2001, 04:42 AM	#7
n2ojunkie Registered Member Join Date: Jan 2001 Location: san diego, ca Posts: 17	thats a lot of work on a system that has an high failure rate. the spider system that your are talking about has a problem with the gas carbonizing in the poppet valves and causing them to stick. this happens when ever the vehical with the system sits for about a week or longer. also the regulators have a high failure rate. gm has put a 100k mile 10year warnte extension on those units. so i would recomend staying away from thoes. i dont think that a injector has material that can be threaded on it. you really need to sandwitch it togher. now you dont need to make rails. just make a sandwitch tab of some kind to hold each injector that will also retain your fuel lines on the injectos. then all you have to do is run the lines to a distrubtion block and fuel press reg. painless wireing makes a gm harness and a ford harness that you can use to wire up either brands fi systems on your car. so you can get factory reliablity. then you would want to get a chip burnt for the custom aspects of your motor. good luck.