I have a 69 vert with a ZZ454 crate engine with a Tremco 5 speed manual transmission.

I want to upgrade to Fuel Injection and want input from those of you who have done so.

Should I go with a port injection system or a throttle body system ?
Which manufacture do you suggest, and why ?

Fuel return system or not?

Thank you in advance to those of you who respond.

 

If you can afford the $1000+ additional cost go with the port injection because it'll produce more power from the very accurate timed injection, Throttle body injections are nothing more than a fancy carburetor that still allows the fuel to smear on the insides of the intake runners.

 

My advice is to go with an all in one kit type system. Do not try to mix and match things that they say will go together without you being an expert on how to create all the fuel mapping pages that will be required to make it run right. I have run into many issues with the computer not liking the signals from the dist and other unforeseeable things that would be worked out in a kit with all the parts required to make it work.

 

To define my questions I would like to add that I'am asking about which manufacture and system type people have used and the results.

I would purchase a complete system and not try to put together a system on my own.
I have a new DUI distributor curved for my ZZ454 engine, so I don't require one with the system I end up with.

 

I've had great luck with Holley systems...but most of them have been the HP or Dominator versions. I would go with a port injection and a return style if I was going to go to all the trouble to do one.

Their software tunes for itself or will let you play around with whatever you want to do. Very versatile. I'd also modify the distributor to allow the Holley EFI to control the timing also...just makes everything work together great.


JIM

 

As a dissenting view, I personally like the carb replacement style throttle body systems - purely because they look 'right' to me in the engine bay, particularly if some care is taken with placement of the additional wiring. I love my Fitech setup, but the Holley Sniper probably has the edge on it now (they weren't available when I bought my Fitech). No one yet has picked my car as being fuel injected when looking at the engine until I've pointed it out to them. Mine runs great, and I use it to control timing too.

 

You can also get port efi on many standard-looking intakes with a 4-barrel throttle body mounted where carb was for that "look". It doesn't have to look like a late LT1. On a side note, they had no damn right to re-use LT1, LS5-6-7 designator over...

 

Sure, but you still end up with a mess of fuel rails and wiring - it will never look like a carbed engine. Again, purely personal preference and I know many will disagree with me.

 

I’ve run and installed both throttle body style (FITech) and full sequential port systems with digital ignition (Holley HP). The main advantage to the full sequential setup is the improved fuel distribution of having the injector shoot right at the back of the valve, and the tunability of the software- which is very powerful.

You can set individual fuel trim for each cylinder, and if you have COP ignition, set individual spark trim for each cylinder as well.

This is very effective, but other than professional tuners and racers, few street cars will take advantage of these capabilities.

The newer throttle body systems such as FITech and the Holley Sniper are pretty advanced and a great value for the money. For a naturally aspirated street engine, they are probably a better choice unless the owner really wants to get deep into software tuning.

I prefer the Holley software, I think they do a better job with the Sniper user interface, but the FITech has a wider range of available features and is better suited to higher horsepower applications. Support for the Holley is a little better. Holley is a somewhat behind the curve in both features and higher HP throttle body applications as I’m sure they are concerned (rightfully so) that this will eat into their market for the more expensive Terminator and Dominator EFI systems.

We did a back to back comparison of an FITech system on an engine dyno against a 850 Holley carb, the FITech made almost exactly the same HP and about +7 lb/ft more torque on a mild stroker LS. We also measured fuel distribution with an O2 sensor in each primary tube, the carb was better (more consistent cylinder to cylinder distribution) but the FITech was not far off and certainly acceptable.

Hard to go wrong with either choice, but if I had a 450-550 Hp motor I’d probably go for the Holley Sniper, anything over that I’d go with FITech ( for the shorter duty cycle with the larger injectors). If I had forced induction I would go full sequential Holley HP or Dominator.

Either way, make sure you do the fuel system right, this means an in-tank submerged pump, properly sized and routed fuel lines, both supply and return.

 

For fuel system, you can pick up an 82 fuel sender new for around $100, plus about $40-50 for an in-tank pump. Nice clean install and no noisy, external pump. Return line needs to be upgraded to 5/16". Rerouting the fuel lines probably the most challenging part of the swap but nothing planning and patience can't overcome.

I did a TBI system from GM junkyard parts this summer and love it. Aside from my 5 speed swap, best upgrade I've done.

You should first upgrade your alternator before taking on the fuel injection. A CS144 is a great unit and easy to drop in.

 

I went with TB EFI and decided if I ever had to overhaul the fuel system I'd rather have a center-mount throttle body and port fuel injection. There's a lot of drivability problems that can be solved. My TB EFI is pretty good now, but not as crisp as even an 80's TPI car that wasn't in the best of shape. That said, I'm running MSD Atomic EFI and the injectors are above the throttle blades which I can't help but imagine is terrible for fuel distribution/emulsification at closed/low throttle.

I agree that you'd have rails and injector wiring, but it would still look pretty correct with a carb-style air cleaner and distributor.
I agree - the fuel lines were a pain in the butt on my swap. One thing about going to an 82 sender, although that will give you the ability to get the rail pressures you need, it will run the risk of starving the fuel pump when your tank is low. No sump. If this car is intended for any kind of performance duty, it's not an issue.

I went with an Aeromotive Phantom setup. More $$, yes, but much less risk of zero (or worse, low) rail pressure.

 

I have had the following Fuel Injection Systems (with comments in parantheses):

Holley Projection- 2 barrel throttle body- analog, on a Chevy 327 (Actually ran OK with this thing.... it was fun to play with with)

GM MEFI-3 running a Ram Jet 350 with it's associated distributor. (Always reliably ran this ECM - no ability to tweak it so.....I wired a GM ECM 122730 in parallel with it {just in case one failed I could swap over ECMs}).

GM 1227730 ECM running a Ram Jet 350 with me programming the chips using the GM Ram Jet associated distributor. (It was fun to learn and program, but I would not do it again, because......I installed a EZ-EFI 2.0)

FAST EZ-EFI 2.0 running the Ram Jet 350 with a Locked-out MSD 8572 distributor, and with timing and EFI being controlled by self-learning EZ-EFI 2.0. (This thing is fantastic, self learning, and it ran better with this than with any of the others).

I would recommend a self-learning, stand-alone system, of whatever name brand you prefer. I have a return-type fuel system where I fabricated the fuel tank components, but I would recommend adapting the 82 Corvette fuel-filler/fuel-sender combo contraption ---- it's too much work to fabricate your own when that already exists. I hope that gives you a little guidance.

 

Today, the Holley Sniper is probably the easiest way to go. The system seems to have a fairly impressive feature set from simple answer a few questions self tuning to things like launch retard, boost control or nitrous control. It has a built-in regulator so you have to plumb a full return line setup.

As mentioned, you can use a 82 sender unit for a pump, but the tank isn't baffled or sumped which can cause fuel starvation issues when the tank is low. There is a Holley hydromat that will fit the bottom of the pump you'd use on that sender, so I would recommend looking at that as the simplest solution.

I would recommend you convert to timing control by the EFI system. The EFI can do the timing much more accurately than a mechanical system. It also gives you more tuning ability as you learn more about fuel injection. For example, one of my cars would knock at a certain rpm with a certain amount of throttle. I just looked at the MAP and RPM when it knocked and went to that location in the timing table and pulled a little timing. I didn't have to make changes that affected it running anywhere else. IF you don't want to do it all at once, then get the EFI running first and convert to timing once the rest is sorted out.

I see too many people commenting on FiTech having poor after sales support and FAST EZ-EFI systems having noise issues to believe the issues were isolated complaints. It sure seems like both are actual issues.

 

I have EZ-EFI 1.0 in my convertible. Today I would buy Holley I think.
I have inline fuel pump from FAST, it works fine, but today I would go for in tank.

This is how I get my gas to the engine, and return to tank.