Era fia fast efi 8 stack project...

[Akimbeau]

NEW FUEL SYSTEM…
I decided to use a return system with an in-line pump. I removed the tank and had an extra bung welded to the bottom. I used my old fuel line for the return line and ran a new high pressure line along the right side frame rail. The fuel system requires a fuel pressure switch and a pressure regulator. All of these parts were included in the fuel system kit from FAST but I did need to buy the new fuel line and a lot of AN fittings to connect it all.

[Akimbeau]

THE START UP…
The initial start up did not go well. During the test of the new fuel system, the portion of the set-up wizard where you adjust fuel pressure and check for leaks before cranking the engine, the engine flooded…and I mean FLOODED! It appeared the injectors were stuck open and gobs of fuel was running into the motor. I removed all the plugs and pumped all the gas out, maybe as much as a quart or two! Changed the oil, of course, and then pulled the throttle bodies and fuel rails off to see what was going on.

Well, after much detective work I found the answer. Pilot error. We’re all friends here, right? I can trust none of what I’m about to say will go no further, right? Well, I didn't notice that the pressure regulator had 2 threaded holes in it, one for vacuum and one for a pressure gauge…kinda glossed over the instructions and might have had one too many beers during it’s install. So, I inadvertently hooked the vacuum line to the gauge port and, in doing so, pumped the manifold and the rest of the motor full of gas when I was testing the fuel pressure. Kinda wondered why the pressure never went above 3lb. It was a mess to say the least!

After, remedying my mistake and re-installing the throttle bodies the new test was a success and it finally started.

Attachment 30133

[Akimbeau]

THE TUNE…

When I first started driving the car it sputtered and popped and overall gave me concern that something was amiss, it didn’t seem to be self-learning all that well. I noticed that the coolant temp was reading about 30 degrees cooler on the EFI interface than what the engine was actually running. The manual states that the learning doesn't actually start until the coolant temp reaches at least 160 degrees. So I relocated the sender from the back of the intake manifold to a port in the water neck and the temp readings became accurate. And subsequently the learning began and within 20 or 30 miles the car was very drivable. I now have about 120 miles on it and things are behaving quite well. Starting is instantaneous and it idles smoothly at 750rpm even though it has an aggressive cam. Throttle response is tremendous and there certainly feels like a good increase in HP over the 650 double pumper that it replaced.My plan is to take the car to a dyno and do some power tuning once I put some more learning miles on the car. I also plan to take the car to the Cobra track event at Willow Springs in May and that will give me a good opportunity to adjust the wide open throttle settings. Kinda hard to do in my cul-de-sac…

[Akimbeau]

IN CLOSING...
I debated for some time the decision between going to Webers or the 8 stack injection. The price of the new Webers and manifold would have been about the same, maybe a few hundred less than what I paid for the EFI system and I’m sure installation would have been less than 8 hours for the Webers. I probably spent 50 or 60 hours putting in the EFI system with all the issues I had to overcome. And as much as I want the car to have a high level of authenticity, I think it was a good choice and a fun learning experience without a huge compromise in its authentic appearance. The car will never appear as an original to those that really know, but for those that don’t, I feel it gives a good impression. Like every owner of a Cobra, I’m frequently asked if my Cobra is real. My reply is always the same…”It’s real enough.”

[1795]

Very nice work and I liked the way you provided the ups and downs of the installation. It looks nice. Depending on the lobe separation on your cam, you may have had to change the cam too if you went to Webers. I was looking at Jim Ingleses' website thinking about maybe down the road changing to Webers and you cannot run them well with lobe separation below 110 degrees, so in my case I would need to change out the cam.

Have fun with it and when you take it to the track take some video!

[Akimbeau]

Originally Posted by 1795

Very nice work and I liked the way you provided the ups and downs of the installation. It looks nice. Depending on the lobe separation on your cam, you may have had to change the cam too if you went to Webers. I was looking at Jim Ingleses' website thinking about maybe down the road changing to Webers and you cannot run them well with lobe separation below 110 degrees, so in my case I would need to change out the cam.

Have fun with it and when you take it to the track take some video!

Similar to the Webers, the cam can give you issues with the fuel injection as well… Especially the self learning systems. They recommend at least 10 pounds of vacuum at idle. A simple vacuum test will give the answer of whether or not the current cam will work well with the system. Mine was right at 10 pounds so it gave me the confidence to go ahead with the conversion without changing the cam. I'm not sure that my cam would perform well with Webers though.