Converting a 1977 Nova to EFI

[Matt Cramer]

Thought some of you guys might be interested in a project I'm involved with at work.

Carb to EFI Nova



We're exploring different ways of converting a Nova to EFI, starting with swapping on a TBI and trying more things from there.

[Caveman]

Re: Converting a 1977 Nova to EFI

Keep us posted!!

Especially when you get to TPI stuff! Or are you gonna skip that and do something else?

[Matt Cramer]

Re: Converting a 1977 Nova to EFI

We're thinking aftermarket intake manifold, though it's possible we may go back and try a junkyard TPI later. There's a media deadline on part of the article and we weren't able to find a used TPI manifold quickly enough.

[TheSilverBuick]

Re: Converting a 1977 Nova to EFI

So, where'd you mount the MegaSquirt and relays? ;D (I'm going to be doing that soon)

[dieselgeek]

Re: Converting a 1977 Nova to EFI

So, where'd you mount the MegaSquirt and relays? ;D (I'm going to be doing that soon)

as soon as I can exorcise the demons from yours... argh that thing is crazy! (can't find a thing wrong with it, BUT it did the same thing when we tried it on a friend's TBI truck, resets and noise like a mofo)

[Matt Cramer]

Re: Converting a 1977 Nova to EFI

So, where'd you mount the MegaSquirt and relays? ;D (I'm going to be doing that soon)

The MS is on the kick panel:



We may do something to put it out of the way later.

The relay board is on the firewall. You can see it in this shot.



We've just dropped a late '80s HEI distributor in and are working on tweaking the spark map now.

[dieselgeek]

Re: Converting a 1977 Nova to EFI

yikes, did you let Jerry do all the wiring on that one Matt? :D

[seanm]

Re: Converting a 1977 Nova to EFI

Very informative stuff. Really like the video of the configuration. Configuring was the most confusing part on a friends 2.3T we did. How do you like the tuner studio? Been playing with it and it seems easier to use to me. (But have no MS to hook it up to and really test yet)

Thanks for posting.

[TheSilverBuick]

Re: Converting a 1977 Nova to EFI

Yeah, I don't think the kick panel mounting will work for me (too much snow, mud and water :P), but I'll probably mount it behind the glove box like I did the T-bird. I like where you've mounted the Relay Board, but it doesn't look like you have an A/C box :'( I'll check on room on mine anyways I used the same TBI adapter plate on my T-bird.

So that's a 7-pin HEI in there? Just to verify, how did you wire that to the relay board? I've modified a Buick 4-pin HEI to a 7-pin and intend on using it on my car.

And last question, are you using MS1 or MS2? ;D

Thought some of you guys might be interested in a project I'm involved with at work.

Nope, no interest at all ;D

[greenjunk]

Re: Converting a 1977 Nova to EFI

is that a column shifted nova? ;D

[Matt Cramer]

Re: Converting a 1977 Nova to EFI

yikes, did you let Jerry do all the wiring on that one Matt? :D

You must have seen his wiring elsewhere. At least his wiring isn't half as scary as the guy who rewired my Spitfire.

Yes, it's a column shift. And we've been using Tuner Studio mostly on this project; it's working out pretty well for us.

This one is running MS2 and we will post the details of how we wired up the 8 pin HEI soon. That article shows a 4 pin fuel only setup. Jerry's been tuning the 8 pin spark curve these past couple days.

[cuda68]

Re: Converting a 1977 Nova to EFI

Nice article on the Nova EFI conversion. I have a question for you though. With a MS system set up in a vehicle for fuel control only is there a way to monitor and record the ignition map of the factory distributor using the sensors on the MS system. I realize if this is possible the map you would generate would not be the greatest tune but I figure it should provide a fairly safe starting point. Obviously I am an amateur at all this EFI stuff so any insight would be helpful.
Thanks,
Pat

[dieselgeek]

Re: Converting a 1977 Nova to EFI

Nice article on the Nova EFI conversion. I have a question for you though. With a MS system set up in a vehicle for fuel control only is there a way to monitor and record the ignition map of the factory distributor using the sensors on the MS system. I realize if this is possible the map you would generate would not be the greatest tune but I figure it should provide a fairly safe starting point. Obviously I am an amateur at all this EFI stuff so any insight would be helpful.
Thanks,
Pat

no, there's no way to log what the ignition timing is doing when you don't have control of it with the MS.

The way to start figuring out your timing map is pretty simple though, if you DO set it up for ignition control: you can take one of the published "curves" for your engine and enter that into your spark advance table. Then, fine tune using the same methods you'd use tuning a non computer, or aftermarket ignition: plug reading, track times, chassis or engine dyno, etc. From there, especially if you have an aggressive cam profile or other similar mods, you can deviate from the typical advance curves to get idle/drivability improvements. Being able to move timing from 10 degrees to 45 degrees at any point in the load/RPM range, is a real benefit to making a firebreathing monster behave well on the street and for cold start.

[cuda68]

Re: Converting a 1977 Nova to EFI

no, there's no way to log what the ignition timing is doing when you don't have control of it with the MS.

The way to start figuring out your timing map is pretty simple though, if you DO set it up for ignition control: you can take one of the published "curves" for your engine and enter that into your spark advance table. Then, fine tune using the same methods you'd use tuning a non computer, or aftermarket ignition: plug reading, track times, chassis or engine dyno, etc. From there, especially if you have an aggressive cam profile or other similar mods, you can deviate from the typical advance curves to get idle/drivability improvements. Being able to move timing from 10 degrees to 45 degrees at any point in the load/RPM range, is a real benefit to making a firebreathing monster behave well on the street and for cold start.

Thanks for the information. Where would be the best place to find a source for timing curves? If I have the initial and total timing, along with the respective RPM those events occur at, could I just use those two points then fill in the blanks in between to create a map? I am in the process of installing a centrifugal style supercharger on the 383 in my old Barracuda, I figure allowing the computer to control the timing would be the best thing to do for this situation.
Thanks again for your help.
Pat

[dieselgeek]

Re: Converting a 1977 Nova to EFI

You have all the info you need! set your idle area (it's based on RPM and Vacuum or MAP) with the "base timing" and ramp it up with higher RPM (and decreasing vacuum) to match the RPM that the timing is "all in" and then leave it consistent from there.

The one most important thing that differs from what you're used to: the EMS needs to be calibrated, meaning, you need to adjust the "trigger angle" so that a timing light always shows what the computer believes is accurate timing. That's it.

-scott