Aftermarket EFI
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Pro
Joined: Nov 2014
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From: Mishawaka Indiana
Aftermarket EFI
Deciding which TBI unit to choose. Holley Sniper, Summit Max 500 or Fitech. Anyone here have experience with any of them? I like the price of the Max 500 especially since the ECU is external and wouldn't have to worry so much about under hood temperatures affecting it.
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From: Wisconsin
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Why are you planning on using one of the TBI style ones? Have you already changed your intake manifold?
Thread Starter
Pro
Joined: Nov 2014
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From: Mishawaka Indiana
Pro
Joined: Dec 2018
Posts: 733
Likes: 424
From: Wisconsin
2023 Corvette of the Year Finalist - Modified
2022 C4 of the Year Winner - Modified
Finalist 2020 C4 of the Year - Modified
So you haven't changed the intake yet? You could keep the factory intake and use one of the other aftermarket systems. You're already going to have to add a distributor if you go the TBI route. The Holley Terminator X (and X Max has transmission control if you have an automatic) would work with the factory intake and injectors plus: it will run coil near plug (LS coil packs) if that's what you are after.
Just another option available.
If you read on the Holley EFI forums, you'll find that the Sniper can have issues from RFI. The ECU is in the "carburetor" and it is sensitive to electrical noise. I'm not sure if the other systems you're considering have similar issues.
Just another option available.
If you read on the Holley EFI forums, you'll find that the Sniper can have issues from RFI. The ECU is in the "carburetor" and it is sensitive to electrical noise. I'm not sure if the other systems you're considering have similar issues.
Safety Car
Joined: Jun 2017
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From: North Georgia, USA
This is for the 1992 with the LT1 engine?
What will you be doing for ignition? I know Holley has an add-on "HyperSpark" ignition system that works with conventional distributors. I'm not sure it'll work with the Opti on the LT1.
For full EFI (8 injectors, not TBI), I also know that folks have set up MegaSquirt-II (or MegaSquirt-III) systems on LT1 engines using a wasted spark distributorless system (with a 4 coil pack).
What will you be doing for ignition? I know Holley has an add-on "HyperSpark" ignition system that works with conventional distributors. I'm not sure it'll work with the Opti on the LT1.
For full EFI (8 injectors, not TBI), I also know that folks have set up MegaSquirt-II (or MegaSquirt-III) systems on LT1 engines using a wasted spark distributorless system (with a 4 coil pack).
Thread Starter
Pro
Joined: Nov 2014
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From: Mishawaka Indiana
So you haven't changed the intake yet? You could keep the factory intake and use one of the other aftermarket systems. You're already going to have to add a distributor if you go the TBI route. The Holley Terminator X (and X Max has transmission control if you have an automatic) would work with the factory intake and injectors plus: it will run coil near plug (LS coil packs) if that's what you are after.
Just another option available.
If you read on the Holley EFI forums, you'll find that the Sniper can have issues from RFI. The ECU is in the "carburetor" and it is sensitive to electrical noise. I'm not sure if the other systems you're considering have similar issues.
Just another option available.
If you read on the Holley EFI forums, you'll find that the Sniper can have issues from RFI. The ECU is in the "carburetor" and it is sensitive to electrical noise. I'm not sure if the other systems you're considering have similar issues.
Safety Car
Joined: Jun 2017
Posts: 4,786
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From: North Georgia, USA
Another question is the dash. Is this a street driven car? Do you need your dash gauges?
Any aftermarket ECM will need a whole new dash with aftermarket gauges. The factory ECM runs the factory dash gauges. If you ditch the factory ECM, those factory gauges and lights are useless.
Any aftermarket ECM will need a whole new dash with aftermarket gauges. The factory ECM runs the factory dash gauges. If you ditch the factory ECM, those factory gauges and lights are useless.
Pro
Joined: Dec 2018
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From: Wisconsin
2023 Corvette of the Year Finalist - Modified
2022 C4 of the Year Winner - Modified
Finalist 2020 C4 of the Year - Modified
I have the needed the intake for the conversion. I have asked and asked about youre talking about and it always seems to be a guessing game or incomplete information so decided to go aftermarket. The Max 500 external ECM is also a reason I like about it. Its the only one Ive seen thats external.
What transmission are you planning on using?
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Thread Starter
Pro
Joined: Nov 2014
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From: Mishawaka Indiana
Another question is the dash. Is this a street driven car? Do you need your dash gauges?
Any aftermarket ECM will need a whole new dash with aftermarket gauges. The factory ECM runs the factory dash gauges. If you ditch the factory ECM, those factory gauges and lights are useless.
Any aftermarket ECM will need a whole new dash with aftermarket gauges. The factory ECM runs the factory dash gauges. If you ditch the factory ECM, those factory gauges and lights are useless.
Thread Starter
Pro
Joined: Nov 2014
Posts: 527
Likes: 23
From: Mishawaka Indiana
This is for the 1992 with the LT1 engine?
What will you be doing for ignition? I know Holley has an add-on "HyperSpark" ignition system that works with conventional distributors. I'm not sure it'll work with the Opti on the LT1.
For full EFI (8 injectors, not TBI), I also know that folks have set up MegaSquirt-II (or MegaSquirt-III) systems on LT1 engines using a wasted spark distributorless system (with a 4 coil pack).
What will you be doing for ignition? I know Holley has an add-on "HyperSpark" ignition system that works with conventional distributors. I'm not sure it'll work with the Opti on the LT1.
For full EFI (8 injectors, not TBI), I also know that folks have set up MegaSquirt-II (or MegaSquirt-III) systems on LT1 engines using a wasted spark distributorless system (with a 4 coil pack).
Safety Car
Joined: Jun 2017
Posts: 4,786
Likes: 425
From: North Georgia, USA
You seem to have all the right answers. With HEI, I'd look more at the systems that have the control module mounted separately (hopefully inside the car). The Sniper units especially are sensitive to interference from noise, and the HEI system is a big source of RF noise sitting right behind it. I know of at least two aborted Holley Sniper attempts with HEI ignition, where the people went back to a 4 barrel carburetor after giving up on the Sniper unit.
And this is a manual transmission? The stock ECM also controls the 4L60E automatic transmission, so if you have that, you'll need an aftermarket controller for it, or a system for TBI that includes wiring and the control logic for the 4L60E.
And this is a manual transmission? The stock ECM also controls the 4L60E automatic transmission, so if you have that, you'll need an aftermarket controller for it, or a system for TBI that includes wiring and the control logic for the 4L60E.
Thread Starter
Pro
Joined: Nov 2014
Posts: 527
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From: Mishawaka Indiana
You seem to have all the right answers. With HEI, I'd look more at the systems that have the control module mounted separately (hopefully inside the car). The Sniper units especially are sensitive to interference from noise, and the HEI system is a big source of RF noise sitting right behind it. I know of at least two aborted Holley Sniper attempts with HEI ignition, where the people went back to a 4 barrel carburetor after giving up on the Sniper unit.
And this is a manual transmission? The stock ECM also controls the 4L60E automatic transmission, so if you have that, you'll need an aftermarket controller for it, or a system for TBI that includes wiring and the control logic for the 4L60E.
And this is a manual transmission? The stock ECM also controls the 4L60E automatic transmission, so if you have that, you'll need an aftermarket controller for it, or a system for TBI that includes wiring and the control logic for the 4L60E.