I would like to convert my 454 to fuel injection. I would like to hear from anyone who has done this. I was looking at the Holley commander and the Edelbrock systems.

Thanks in advance.

 

Zwede has done this with quite some success. Hopefully he will chime in soon. This is one of the mods on my list also.

Here is TTT for you.

 

Seems someone here put a 2 barrel version of the Holley tbi on a bb and although it is not rated very high he said it is provides plenty for his mild BB.

 

I have the port EFI on mine, but it has similarities with the TBI. I have some info on my webpage in sig (although some pictures aren't working right now).

 

I would like to do this to a 68. However, it does not have a fuel return line (and maybe no provision to return the fuel to the tank). I have seen "returnless" fuel injection but not really sure how it works. Which would be the best to do, add a return line or make my fuel rail into a "returnless" system?

 

Best solution is to add a return line. It's actually not difficult at all. I used 3/8" aluminum line that I ran on the drivers side back to the tank (along the brake line). Some say aluminum line will work harden and crack, but mine has been fine for 3 years now of daily driving. If it worries you you can use steel line. A little harder to bend/install but still doable.

 

I have TBI on my 1980, using the Holley Commander 950 system. I would say that it's far better than the Edelbrock system and was pretty easy to install.

What would you like to know?

 

I think that most people doing a fuel injection conversion on these cars are interested in hood clearance, ECM interface issues and fuel supply (conversion to electric pump, return lines etc.). I am interested in the the fuel supply issues right now. I don't think my 68 tank has any provision for a return line. Also, I am leaning towards Russell braided lines from tank to fuel rail but I want something that is reliable for years. I have used this on race cars but they are replaced every year.

Sorry, I seem to have hijacked this post!! I'll shut up now.

 

Well, hood clearance was no problem, as the TBI unit was shorter than the existing QJet I was running.
ECM interface. You can mount the ECM behind what would be the glove box, or in the glove box if you have one. The cables are not long enough to let you mount it in the storage consoles.
Return line - I had a sump added to my factory fuel tank. For fuel injection, you will almost always want to run a sump. You never want to get air into the system going around a corner or when the tank is low. In the sump, you can have an outlet added to run fuel to the engine and a return for the return fuel as well.
Fuel line. Here is what I did. I ran a new aluminum line down the side frame from back by the tank all the way up to the firewall. At the firewall I converted to rubber / braided line to go up the firewall and into the TBI unit. Coming out of the tank, from the sump, I used rubber/braided line out of the sump, to a pre filter, then to the pump, and then to the main filter. From the main filter it's a rubber/braided line up to the aluminum supply line going to the engine.
Return. I used the factory original "feed" line as my return. I cut it at the frame rail at the firewall and ran rubber/braided line from the TBI unit to where I cut it near the firewall. From there I use the factory line all the way back to the tank. I am running my return fuel right back down the factory supply line and even back into the pickup on the sending unit. I just removed the "sock" at the end of the factory pickup so that it would not restrict the return flow.
Fuel pump and filters. I wasn't running a spare tire carrier, so that made adding a sump easier. I used the cross brace under the tank (where the spare tire carrier used to mount to) to mound my filters and pump to.

 

Here's my GM TBI on a small block. I have a 454 2inch throttle body that I plan to add to it this summer. Painless Wiring sells a harness to retrofit using GM ECU and sensors.

 

How hard was it to tune the system. Im leaning toward the commander. I have a 71 which has a return line. Would I have to change the lines or are the factory rubber / steel lines ok for the higher pressure.

 

You can't use the factory return line. The return must be at least a 5/16" line, and preferably a 3/8" line. The factory rubber and steel lines are fine for return line pressure, because you are only talking about 1-3 PSI max. In fact, if you have more return line pressure than 5 psi then either the line is too small or it's too restrictive and it will cause tunning problems.

The commander was very easy to tune, but you must have a laptop to do it right. I took my car to my local EFI specialists and let them have it for a few days to do the tuning on a dyno. It cost me about $1K in dyno time, but I now have the system tuned to run in open or closed loop with the timing advances and the mixtures set correctly and verified by a wide band O2 sensor, dyno results and a knock sensor.
You don't have to get it dyno tuned, but I wanted to get every last HP out of the car while running on pump gas in 110+ heat and not have any detonation due to timing. Dyno tuning was just the fastest way to get that all done.

Best thing to do is download the tuning manual from Holley and read through it. http://www.holley.com/HiOctn/TechSer...o/R10149-5.pdf
And here is the install manual - but most of the install is "custom" to the specific vehicle. http://www.holley.com/HiOctn/TechSer...o/R10179-1.doc

Here is the system that I am running -- http://www.holley.com/HiOctn/ProdLin...B/950-22S.html

 

How did you come up with a fuel sump?

 

I installed (about 8 years ago) a Holley Pro-Jection 4 TBI for my 350. Once you get it "tweaked", the system is AWESOME! Would definitely recommend it over a "carb" sytem. Every morning...turn the key....off I go!!!!

 

What I did was to drill a bunch of holes in the tank, and then enclose the are under the tank to make a sump. The holes allow fuel to drain down in the tank, but stop it from sloshing back out under hard manuvers. This lets me get every last drop out of the tank.

I had a local shop do the welding. They just welded a box right to the bottom of the tank and installed the fittings.

A view from inside the tank.

 

Why Why Nothing beats a nice running carb. Stay with the carb and enjoy driving the vette vs under the hood fiddling and getting all pissed

 

HA !

Fuel injection, particularyly Mult-Port, is WAAAAY better than any carb around. I would put my TBI system against any carb ever made. I can make adjustments to mixture, timing, idle, and many other items while driving for reat-time results. I can also let the computer do it's own thing and have it always give me the best mixture results based on the all the sensor inputs. No carb can do that, ever. I can run at 1000 feet in Phoenix or 8000 feet in Flagstaff and not have any problems at all. The system automatically adjusts many times per second based on input from all the sensors.

Before I was running a QJet that was tuned using an O2 sensor for best results. I averaged about 14 - 16 MPG and was only running 15.0 - 15.3 in the quarter mile. My last run at the strip was a 14.3 with a bad transmission and my last curise (same bad POS tranny) I got over 22 MPG. When we stopped to get gas on our cruise, my 1980 with fuel injection used the same amount of gas as all the C5 owners who were also filling up.
I have INSTANT throttle response, it never stutters, burps, or backfires and starts each and every time I turn the key. I don't have to pump the gas or worry about setting the choke, it always starts.

How on earth can you say that a carb can compete with that? A carb will not give near the drivability, tunability or reliabilty that either a TBI or MPI system can give.

A properly tuned carb is good for power. But if you change the air temp, altitude, load, or any other condition you will not be making optimal power and efficency unless you tune again. I never have to worry about that again.