C3 Tech/Performance V8 Technical Info, Internal Engine, External Engine, Basic Tech and Maintenance for the C3 Corvette

EFI conversion

Old 05-03-2019, 07:50 PM
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I installed the FAST EZ EFI 2.0 multiport. Jury is still out. I had some installation issues. Nobody makes a throttle bracket and return spring setup that works right with this throttle body so I had to make my own out of an off the shelf FAST bracket and a welded on extension/other manufacturers return spring.

On the engine dyno, it fired right up and idled great. We pulled 7 times and gained a lot of power through the ECU learning to put more fuel in.

On the street, it hasn't quite had the same success yet. I still have some off idle problems (manual trans), and the power isn't near where it should be according to the dyno numbers. It starts and runs great, but it doesn't seem to learn at all. I have fixed a lot of minor issues (unrelated to the actual FI system) that may have caused it to not live up to its potential, but as of right now, I can't tell you to go ahead and buy one. The online support is terrible. They don't return emails and their message board isn't even staffed by their own employees.

I did, however, do the same thing as redcruz1120 and install a Tanks, Inc tank, in tank pump, and sender setup and am totally happy with that.

If things change and it starts acting more like I thought it would, I will happily update.
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Old 05-03-2019, 08:19 PM
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St. Jude Donor '09

Originally Posted by gtmsomeday View Post
I don't see 'dropping the boot' on the handheld. What do I look for?

Its the adjustment under Primary /Secondary on the handheld settings. I believe you have to go under System Settings to get there. It should be on that link above.
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Old 05-07-2019, 07:56 PM
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Update. Spent the entire day Sunday correcting 2 major issues (with relatively easy and cheap fixes) that were causing me problems. I am positive both of these issues were screwing up the learning function and power level. One was totally my fault and one I consider to be a mistake on FASTs part. I spent a lot of time scratching my head and chasing things, but these were the last two and made all the difference in the world. Engine now runs fantastic in the car. It fires and idles perfectly, and I am feeling every one of the 500+ HP. Wish I would have had some more info in the manual and online to help me but I think its there now.

There is definitely a learning curve with installing an EFI system!
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Old 05-16-2019, 12:45 AM
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Originally Posted by Greengear View Post
I did the holley sniper and hyper spark distributor combo. Did the progressive throttle upgrade too. Put the pump in the tank with a home made mount/ baffle. Used the factory steel feed and return fuel lines. It has been really nice. Allows everyday driver status despite heavy traffic where I drive. I did 0 tuning. It really does self learn ( except progressive throttle upgrade required changing settings )
The factory 3/8" supply and the 5/16" return ? I ask because I've chosen the Holley Sniper 4150 Self tuning Master kit after I had bought a new original style tank. I see that on the Holley install manual "they recommend" a 3/8" return line but on the Holley install video they show 5/16" as minimum size. Were you aware of this ? Any insight/photos of your install would be greatly appreciated.
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Old 05-16-2019, 02:22 PM
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I put an MSD Atomic EFI in mine just because they don't require a return fuel line. I am more than happy with it.
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Old 05-16-2019, 05:55 PM
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Originally Posted by Miketheray View Post
I have a 71 with a small block. I'm thinking of converting to EFI. I'd love to hear from others that have already converted. What manufacturer? What issues did you encounter? How does your car run now?

Any and all feedback is welcomed.
68 with an Al head 496. I installed the Holley Sniper EFI, Holley Hyperspark coil, ignition module, and distributor as well as the Holley gas tank with the in-tank fuel pump. Super easy to install. It started right up. It does go into a learning mode and will learn over time. I will say that the more radical your cam, the more you need to have it professionally tuned. I did that and it made a huge difference. I picked up about 25hp (they dyno'd it afterward) and it runs awesome. Result is several great things: 1) Easy starts cold and hot. 2) No vapor lock. 3) Smoother low RPM driving. 4) Better throttle response.

BTW here is a thread I did about what I learn on my install.
EHI Thread

And here is my build thread that ends with the dyno run

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