[jonathonar89]

I've been debating about making a carb to efi swap with a few friends for a little while now. My mild 400 currently has no intake manifold on it...used to have an RPM and Barry Grant carb.

There's a lot of system choices...
Holley EFI, FAST, diyautotune, Big Stuff 3, etc.
Distributors...trigger wheels
Direct port manifolds vs tbi
4500 vs 4150

Where would an efi newbie start?

[Chris Petersen]

Sit down and plan for a lot of reading...

http://www.megamanual.com/index.html

[TheSilverBuick]

Pick one and stick with it.
Do you want to piece most of it together or do you want plug and play?
Do you want it to just do fuel or do a bunch of other stuff too including ignition control?
Are you going for every last HP, or does close/95% count?
How much technical support help do you think you'll need?
You can't have too big a throttle body, just make sure the linkage is progressive if large.

[lfdsteve]

I would post a no for the powerjection 3. I'm running it on my 462 and although it works ok, I have had to replace just about every component except the body.
Temp sensor, iac, TPS, fuel pump and filter. Oh and software only runs on xp or older.
Just food for thought.
Steve

[Ollie]

Another vote for MegaSquirt.
MegaSquirt support forums.
http://www.msextra.com/forums/index....112a6a1c5d28ad

[jonathonar89]

I couldn't find much information on 4 pin module HEI distributors. Is there a way to modify one for computer controlled timing? I have a 1979 Pontiac 400 distributor. Diyautotune looks very interesting.

[Ollie]

To modify the HEI for computer control. Disable the mechanical and vacuum advance.
There are several ways to disable the mechanical advance. 1 remove the fly weights, screw the two parts together, or weld the two parts. The vacuum advance disconnect the vacuum hose and crimp the nipple. the shaft that moves the reluctor can be welded in place.
Obtain a distributor from a computer controlled 301. They do not have mechanical or vacuum advance.

[Chris Petersen]

I dont think you can use the 4 pin module to control timing.

I did mine by taking out the 4 pin,weights and springs, and tack welding the plates together. The two sensor wires I ran outside the dist, and hooked it to an 8 pin module from a 90's GM. Mounted it outside the dist. Will work on its own just like the 4 pin, but has a tach out to go to the ECU, and another wire that you can hook up to tell the module via the ECU to command the timing values.

I pretty much did this, just started with a Pontiac dist.

http://www.diyautotune.com/tech_arti...part2-nova.htm

[Ollie]

Yeah, Chris missed the part about 4 pin module, have to use a 7 or 8 pin.
This is a link to wiring in a 7 or 8 pin module. Does not have to be mounted in the distributor.
Scroll down the page about half way.
http://www.msextra.com/doc/ms2extra/MS2-Extra_HEI.htm

[Chris Petersen]

Also would like to note, the module does get hot, it was meant to be mounted to the dist base, with heat sink compound, using the aluminum base as the heat sink. I had mine running for 5 minutes just hanging in the air, got almost to hot to hold in my hand. I am going to make a heat sink out of a piece of aluminum and mount it to the firewall.

[TheSilverBuick]

I vote MegaSquirt too if you are willing to do the homework and ground work.

HEI's are cake to use. I roll pinned my mechanical advance and simply removed my vacuum advance. Never even pinned down the pickup coil and it hasn't moved. A friend of mine made this really slick mechanical advance lock using a thin piece of aluminum plate with 4 small holes in it that the posts for the springs sit in. The rotor holds it in place.

This is mine. I have the small pickup coil plug because I used a 7-pin module to control timing for about 1 month (complete waste of friggin time) before simply connecting the MegaSquirt right to the pickup coil like this. The 4-pin coil with the wider plug works fine. I put around 40,000 miles on that setup. Then I went to a crank trigger and then a year after the crank trigger coverted the pickup coil to a cam sensor and went sequential. Incrementalling upped the complexity of the build as I've become more comfortable.



I started with fuel only. So a simple wire from the tach port of the 4-pin vacuum/mechanical HEI and batch fire fuel. A month later I pinned the advance plates and converted to a 7-pin HEI, then a month later ditched the module altogether (aka should of skipped it) and ran straight off the pickup coil with Megasquirt controlling timing and still using batch fire. Three years later I went to a crank trigger (still used the distributor cap, rotor and HEI coil to dispense spark). Then a year after that I converted the HEI's pickup coil to a cam sensor by grinding all but one tooth off the pickup coil and reluctor. Then about year after that I went distributorless. All in steps.

[Chris Petersen]

Originally Posted by TheSilverBuick

I vote MegaSquirt too if you are willing to do the homework and ground work.

HEI's are cake to use. I roll pinned my mechanical advance and simply removed my vacuum advance. Never even pinned down the pickup coil and it hasn't moved. A friend of mine made this really slick mechanical advance lock using a thin piece of aluminum plate with 4 small holes in it that the posts for the springs sit in. The rotor holds it in place.

This is mine. I have the small pickup coil plug because I used a 7-pin module to control timing for about 1 month (complete waste of friggin time) before simply connecting the MegaSquirt right to the pickup coil like this. The 4-pin coil with the wider plug works fine. I put around 40,000 miles on that setup. Then I went to a crank trigger and then a year after the crank trigger coverted the pickup coil to a cam sensor and went sequential. Incrementalling upped the complexity of the build as I've become more comfortable.



I started with fuel only. So a simple wire from the tach port of the 4-pin vacuum/mechanical HEI and batch fire fuel. A month later I pinned the advance plates and converted to a 7-pin HEI, then a month later ditched the module altogether (aka should of skipped it) and ran straight off the pickup coil with Megasquirt controlling timing and still using batch fire. Three years later I went to a crank trigger (still used the distributor cap, rotor and HEI coil to dispense spark). Then a year after that I converted the HEI's pickup coil to a cam sensor by grinding all but one tooth off the pickup coil and reluctor. Then about year after that I went distributorless. All in steps.

May I ask why is was a waste of time using the GM module?

Using MS connected directly to the dist like the pic you posted, can you still controll timing that way?

[TheSilverBuick]

Originally Posted by Chris Petersen

May I ask why is was a waste of time using the GM module?

Using MS connected directly to the dist like the pic you posted, can you still controll timing that way?

The MS has a module built in, so you are adding extra parts (aka extra point of failure) for one and two it's extra wiring for the module. It just "sounds" easier, thinking GM did the engineering for you. Or its what I thought at the time.

Yes, full control of timing that way, and the IGN out wire from the MegaSquirt goes to the negative side of the coil or to an MSD/ignition box (standard +12v power on the positive side of the coil), set your dwell and trigger angle settings in Tuner Studio and have full timing control. I'm pretty sure it's even the same jumper settings on the mainboard as with the 7/8 pin modules, but would be worth double checking. It's been several years since I switched.

Here was my 7-pin conversion. And it worked, I drove the car about 2,000 miles with it in that month or so, but ultimately decided simpler is better.

[jonathonar89]

I made this thread a while ago and just sold my carburetor so I'm going to dive into an efi conversion on my car. Right now the parts I have to start are a holley dominator 1400 fuel pump and 260gph filter.

Any more comments and suggestions are welcome. Working on a '79 400 4spd Trans Am.

[Ollie]

My project is a 79 Trans Am 400 4 speed.
Using MegaSquirt MS3X. I have sequential ignition and fuel.

36-1 Trigger Wheel
Trigger Wheel mounted on back side of balancer.
Fabricated 36-1 trigger wheel sensor mount, with Ram Air Restorations modified timing indicator.
COP mounting.

[Lee]

I recently added a FAST EZ EFI 2.0 system to my El Camino. I went with their full system, including distributor and ignition box. I used the FAST in-tank fuel pump and an new EFI-ready tank from TanksInc.

In all honesty, it had a gremlin in the system when I first installed it. But FAST worked diligently with me, expedited parts for me to troubleshoot, and the system works great for me. Turned out to be a bad connection on the throttlebody wiring harness.

On my chassis dyno, the best the motor (very mild 350 Chevy) ever did with the carb was 214rwhp. With the FAST, I'm up 18hp. The best MPG the carb ever delivered was a bit over 17, and I've had one tank with the EFI that topped 20.

If you are interested in FAST, PM me, and I can possibly help you with the pricing.

[jonathonar89]

Originally Posted by Ollie

My project is a 79 Trans Am 400 4 speed.
Using MegaSquirt MS3X. I have sequential ignition and fuel.

36-1 Trigger Wheel
Trigger Wheel mounted on back side of balancer.
Fabricated 36-1 trigger wheel sensor mount, with Ram Air Restorations modified timing indicator.
COP mounting.

Looks like some nice work, what manifold are you running? Still using the shaker?

[Ollie]

Using the Edelbrock Victor EFI manifold with an Accufab throttle body.
The plan is to use the shaker.
Hight comparison Accufab throttle body and Q jet.
As you can see the throttle body is about half the height of the Q jet.
I have a 1 inch crab. spacer and these air cleaner spacers, to make up the height deference.

[jonathonar89]

Here are some pics of my car and where it's sitting right now. I just took out the entire fuel system this weekend, put a block off plate on the engine and spent a good 3-4 hours taking off undercoating from the gas tank with a wire wheel .






Here are a couple pics of the parts I'm starting out with. I'm about to pick up a Victor EFI manifold with 4500 dominator flange from a member on the forum this week. Please post some ideas/suggestions on how I should install my fuel system.



My engine as it's sitting currently. The Holley intake is for sale in the performance section.

[Ollie]

If it is not too late I would recommend the smaller 4150 flange. The 4100 might cause interference with the shaker.
The Stock 3/8 feed and 5/16 fuel lines are adequate.
For the flex lines do not use rubber, Use PTEF lines.
For a fuel pump I recommend an in tank pump.
What is the depth of the fuel tank at the deepest.