Surprised I'm not getting any response about F.I. for a 73. Has no one tried one of these new kits? Considering it for my 73 project, with stock hood. Anyone? Shop keeps nudging me in that direction. HELP!

 

There are about 10-15 different "kits" out there... Which one are you looking at?
Lots of people run FI, but most people dont because of the cost associated. That seems to be the only downside

 

For not a lot more than the EFI kit for my C3 would cost, I could buy a C4....

 

I've been trying to assess all of them, just trying to figure if any would be a reasonable install. Big money for sure. Just would appreciate some first hand experience with one that worked and fit well from one of the members. Getting a bit frustrating. Thanks again fellow 3C Vette peoople.

 

I tried powerjection III returnless. It fits under the stock hood with 1/2" spacer. Install is easy. Holley linkage so you can find throttle, tv or kickdown brackets. Used teflon lined pre crimped 6AN hoses and added Swadgelok couplings to the hardlines. Electrically it's very simple and compact. Used tanks Inc fuel sump. As I chose returnless I couldn't use a vain pump so installed a turbine style Ford Focus SVT pump.
The issues :
Due to the turbine pump the fuel drained back so one of the advantages of immediate start is already lost.
Retrotek adviced to install a check valve in between the pump and the fuel hardline. This led to fuelpressures after shutdown in excess of 120 psi so the injectors started opening and fuel was dripping into the throttle body.
Ok, install a regulator but couldn't really find a place in the back to do so (spare tire hub still in place). This kinda beats the idea of a returnless system if you have to install a regulator....
Out goes the returnless module but I didn't have enough space to mount a fuel rail with regulator.
Meanwhile the ECU went nuts and had to be replaced.
Next step : I threw it all out and send it to forum member Binnie during the pay it forward christmas period.
I'm sure other people had more succes, for me it was a expensive mistake. Browse my photobucket page for pictures
Nick

 

I was going to go with TPI on mine, but ended up going with a BG Speed Demon 750 after talking to Jim from Jim's Performance. He told me the TPI would choke my engine setup even with all the extras I put on it like big injectors, BBK 58mm throttle body, SLP runners, etc.

 

Lots of options. Whats your budget and expectations? Here are some options I looked at and what I think of them.

1: Cheap and mild F/I setup
Get a big block TBI that can mount to a carb intake and control it with a Microsquirt/Megasquirt.
This is probably the cheapest and still maintains the carb style air cleaner/look. Not the most efficient F/I setup but also not the most costly.

2: Low to Mid performance and full port F/I
Get a Tune port and install it like any other L98. Can control with a Microsquirt/Megasquirt or a modified OEM computer.
Mid price but will give full port inject. Tune port makes great low and mid power but is not good for a high performance revving motor.

3: Aftermarket Kits
These are the most costly but usually are setup so they are easier to install and control. The port version are the most efficient and can handle low to high end horse power.


What I am probably going to do is I bought a used edelbrock port F/I manifold/throttle body but will control with a microsquirt. This should cost about the same as a tune port but allow more high end power.

 

I put a FAST EFI on my 70 C5. If I had to do it over again, I would probably go with a different vender. All of the FI kits use a 4150 throttle body so if your car has a QuadraJet, you have to use a spacer adapter. On the small block, clearance is probably not a big issue. On the big block it is. I had to mill the spacer down to maximize clearance but it worked out fine. The second challenge was getting the stock air cleaner to fit. I wanted to keep the stock appearance and use the factory air cleaner. I had to do allot of hammer work and also had to modify the breather pipe on the bottom of the assembly. If you're going to use a non-stock filter assembly that problem goes away. If you want to use stock, you might consider the Holley unit because the injectors are low and out of the way. Some of the newer designs are supposedly returnless and require less in the wiring department and that is why I would consider a different vendor, although FAST has a new model that has the dimensions of a holly carb which will probably improve fitment and may have simpler wiring and fuel need features like the competition so it is worth considering. If you go with a unit that requires a return, then you have some plumbing to do. You will need to install a fuel pressure regulator. I initially tried an LS1 set up which has a fuel pressure regulator built into the fuel filter. I installed it near the tank. I had detonation problems. The FAST engineer told my supplier that the LS1 set up is less than ideal because the fuel foams. I'm not sure I buy that because the LS1 set-up is on tons of GM cars out there. Maybe it has to do with how it's plumbed. In any event, I just finished re-plumbing my car to install a conventional fuel pressure regulator in the engine compartment with a return line back to the tank. The supply side is hardlined and the return is hose. It would be difficult to to fit hose in the frame and under the body for both supply and return (if you want a clean stealthy look). I hope to have my car on the road this weekend so time will tell if that was causing the detonation I was getting. You will have to run an electric pump. I went with an in the tank set up so you will have to pull your tank if you are going to go that route. You will need to install an O2 sensor in you exhaust which is easy to do. The units are "self learning" and my car stumbled for awhile but eventually that went away. As for the performance, it works great. The engine fires right up even in the cold. Fuel economy is also improved.

 

I've done several of the Holley EFI setups and have been very impressed with them. I have the bad boy "Dominator" version on my car.....but the HP version is the same platform without all the bells and whistles you don't need. The software works very nice and it will tune itself or let you do anything you want.

Here's a couple of articles I did on them for Auto Enthusiast Magazine.

http://www.carsandparts.com/Articles...ishly-simple-1


http://www.carsandparts.com/Articles...ody-experience


JIM

 

Thanks very much for the experiences and input guys. Impressive efforts you all put forth! On my 73, there is a fuel line that goes into the top right corner of the gas tank. I thought that was a fuel return, am I mistaken, or can that work for the F.I.? Again, really appreciate everyone's input!

 

There should be 2 fuel lines going to the front of your car. 1 is the main fuel line, the other a return. The orignal fuel pump was 3 lines. 1 In from gas tank, 1 Out to carb, and the other a return to gas tank. This was done to fight vapor lock.


Depending on your power and fuel pressure you can probably use the orignal return for a F/I return as well.

 

Interesting! Starting to think the F.I. might be a reasonable effort. Motor will be a 383 stroker, roller rockers, aluminum heads. Looking at the McJacks ram horn headers. So many pieces to this puzzle. Thank you to all those that have gone before me!

 

Hi Frank I looked at the comments and there are lots of good ones. There are a lot of guys going with the TPI system and the more economical TBI. I have a 81 and I went with a MPFI system from AFI. IT looks awesome and I am really pleased with it. You give them your specs and they build a system for you. I dont know your mechanical ability but it is a 5 out of 5 to install. If you want me to send you some pics of how it looks or more details let me know.

 

CMEPASS, Hi, and thanks for your input sir! Would be very interested in seeing the photos of your FI. I'm working with a couple of shops on a total redo on my 73. One shop is allowing me to work at their place, and they help with things I need assistance on.

 

I send you a private message with my cell phone # so I can send some pics. Send me a message to my cell or on the forum if you would rather me send them to a email. I would post some here but cant figure it out Lol.