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

Engine mods - EFI conversion

Thread Tools
 
Search this Thread
 
Old Apr 18, 2016 | 11:39 AM
  #1  
Skybolt's Avatar
Skybolt
Thread Starter
Instructor
 
Joined: Apr 2016
Posts: 169
Likes: 18
From: Stony Brook New York
Default Engine mods - EFI conversion

So I am want to go with an EFI conversion kit, but i am not sure if I can without having to do a whole lot of other mods as well.

I have an 81' and as mentioned and want to swap out the quadrajet for EFI and run true dual exhaust as well. I also don't know why my car has an O2 sensor when it's not an EFI model ...

If I do this Do I need to remove the ECU as will? and if I do that, how do I get the converter to lockup, replace the converter? That may not be worth doing the upgrade then, or make that a winter project sometime in the future ...

I have searched and read a bunch of post's on this but I am thoroughly confused as to the answer.

Thanks guys.
Reply
Old Apr 18, 2016 | 02:24 PM
  #2  
jim2527's Avatar
jim2527
Race Director
20 Year Member
Liked
Top Answer: 1
Top Answer: 3
 
Joined: Apr 2003
Posts: 19,344
Likes: 654
From: Tampa, Florida
Default

Yes, you can do it without a whole lot of other mods, but then again, it depends what consider 'a whole lot' of mods.

There are basic throttle body style kits that go on like a carb and complete multi-port kits. Some people do it for a few hundred bucks with scavenged parts while others spend thousands.
Reply
Old Apr 18, 2016 | 02:33 PM
  #3  
Skybolt's Avatar
Skybolt
Thread Starter
Instructor
 
Joined: Apr 2016
Posts: 169
Likes: 18
From: Stony Brook New York
Default

I guess I should have qualified everything ... Sorry.

I am considering a basic throttle body EFI system, like the Holley one coming out later this year. But that would cause the ECU to not communicate with the Quadrajet and cause a check engine light. I can get an O2 bypass module, but still can't figure out the carb bypass route.

I don't want to remove the ECU if I can help it. I have a TH350 tranny that is solid and I am not ready to replace the torque converter just yet.

Last edited by Skybolt; Apr 18, 2016 at 02:36 PM.
Reply
Old Apr 19, 2016 | 12:09 PM
  #4  
Kacyc3's Avatar
Kacyc3
Drifting
10 Year Member
Liked
Loved
 
Joined: Jun 2012
Posts: 1,990
Likes: 183
From: Port St. Lucie Fl
Default

the new efi will replace your carb, o2, and ecu. Did th350 come with a lock up convertor? either way you find the wiring harness for it and either wire it to a toggle switch or buy the b&m vacuum kit and adjust it to your liking.

Last edited by Kacyc3; Apr 19, 2016 at 12:09 PM.
Reply
Old Apr 19, 2016 | 12:42 PM
  #5  
Skybolt's Avatar
Skybolt
Thread Starter
Instructor
 
Joined: Apr 2016
Posts: 169
Likes: 18
From: Stony Brook New York
Default

Originally Posted by Kacyc3
... Did th350 come with a lock up convertor? either way you find the wiring harness for it and either wire it to a toggle switch or buy the b&m vacuum kit and adjust it to your liking.
I was under the impression that all '81's with automatic transmissions had lockup converters? It would be great if it didn't, because them I'm basically done. Just put in the wrench time and take a drive!

I was looking at the B&M kit on summit. looks like a nice glove box Item if I do need it? If the lockup is electronic I can keep the ECU and dummy up the O2 sensor. I need to look into this. Thanks for your post.

Last edited by Skybolt; Apr 19, 2016 at 12:45 PM.
Reply
Old Apr 19, 2016 | 01:11 PM
  #6  
Skybolt's Avatar
Skybolt
Thread Starter
Instructor
 
Joined: Apr 2016
Posts: 169
Likes: 18
From: Stony Brook New York
Default

So the spec sheets for an 81' state "TORQUE CONVERTER CLUTCH, 2ND & 3RD GEAR LOCK-UP" but does not state electric or manual?

Does anyone know what type is used? I am guessing manual by cable? is that right?

Sorry for asking dumb questions, I have never played around with an automatic, so I don't know much about them.

Last edited by Skybolt; Apr 19, 2016 at 01:20 PM.
Reply
Old Apr 19, 2016 | 01:52 PM
  #7  
Skybolt's Avatar
Skybolt
Thread Starter
Instructor
 
Joined: Apr 2016
Posts: 169
Likes: 18
From: Stony Brook New York
Default

So I found this in a service manual "In 1980 (except California models), an electrically controlled locking torque convertor was introduced to improve fuel economy. All 1981-82 models have this feature."

So I am going out on a limb here and guessing that the lock up is controlled by a modulator and not the ECU, since 80' doesn't have an ECU or do they?

Last edited by Skybolt; Apr 19, 2016 at 01:54 PM.
Reply
Old Apr 19, 2016 | 03:43 PM
  #8  
Skybolt's Avatar
Skybolt
Thread Starter
Instructor
 
Joined: Apr 2016
Posts: 169
Likes: 18
From: Stony Brook New York
Default

on 1980's cars it is controlled by a few engine factors, in 1981 it is solely the ECU and a controller is needed to achieve lockup at speed.

So I can ditch all of the smog and ECU crap and go with a new HEI dist. and EFI throttle body unit if I use the B&M controller.

Well thanks to google this has been a learning experience today! I hope everyone who reads this has a good laugh, I know I sure would ...
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
story-1

2027 Corvette vs The World: Every Model vs Closest Competitor

 Joe Kucinski
story-2

10 Most Common Corvette Problems of the Last 20 Years!

 Joe Kucinski
story-3

5 MOST and 5 LEAST Popular Corvette Model Years in History!

 Joe Kucinski
story-4

2027 Corvette Buyer's Guide: Everything You Need to Know!

 Joe Kucinski
story-5

10 Things C8 Corvette Owners Hate (But Won't Tell You)

 Joe Kucinski
story-6

10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!

 Brett Foote
story-7

Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)

 Joe Kucinski
story-8

Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!

 Michael S. Palmer
story-9

5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!

 Joe Kucinski
Old Apr 19, 2016 | 05:42 PM
  #9  
jim2527's Avatar
jim2527
Race Director
20 Year Member
Liked
Top Answer: 1
Top Answer: 3
 
Joined: Apr 2003
Posts: 19,344
Likes: 654
From: Tampa, Florida
Default

Originally Posted by Skybolt
So I can ditch all of the smog and ECU crap and go with a new HEI dist. and EFI throttle body unit if I use the B&M controller.
I'm sure you can.... A lot of people have 'ditched everything'. Controlling the lock-up should be least of your worries.
Reply
Old Apr 20, 2016 | 02:14 AM
  #10  
SI67's Avatar
SI67
Melting Slicks
20 Year Member
All Eyes On Me
Liked
Loved
 
Joined: Apr 2006
Posts: 2,331
Likes: 60
From: Sunnyvale CA
Default

Originally Posted by Skybolt

I have an 81' and as mentioned and want to swap out the quadrajet for EFI and run true dual exhaust as well. I also don't know why my car has an O2 sensor when it's not an EFI model ...


Thanks guys.
It has an O2 sensor to provide feedback for computer control of the carburetor.

Reply
Old Apr 20, 2016 | 09:24 AM
  #11  
Skybolt's Avatar
Skybolt
Thread Starter
Instructor
 
Joined: Apr 2016
Posts: 169
Likes: 18
From: Stony Brook New York
Default

Originally Posted by jim2527
I'm sure you can.... A lot of people have 'ditched everything'. Controlling the lock-up should be least of your worries.
Only concerned about the lockup so I don't burn out anything, the rest is a cake walk. Thanks for your reply.

Originally Posted by SI67
It has an O2 sensor to provide feedback for computer control of the carburetor.

Thanks, I didn't realize that there was rich/lean valve in the mix. I guess I chose poorly with an 81', I didn't realize that this was the first year with an ECM, I thought only 82' was. I still love the car though and very happy I got her.
Reply

Get notified of new replies

To Engine mods - EFI conversion





All times are GMT -4. The time now is 10:08 AM.

story-0
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE
story-1
2027 Corvette vs The World: Every Model vs Closest Competitor

Slideshow: 2027 Corvette lineup vs the world.

By Joe Kucinski | 2026-04-20 17:58:41


VIEW MORE
story-2
10 Most Common Corvette Problems of the Last 20 Years!

Slideshow: 10 major Corvette problems from the last 20 years.

By Joe Kucinski | 2026-04-14 16:37:05


VIEW MORE
story-3
5 MOST and 5 LEAST Popular Corvette Model Years in History!

Slideshow: 5 most and least popular Corvette model years.

By Joe Kucinski | 2026-04-08 13:25:01


VIEW MORE
story-4
2027 Corvette Buyer's Guide: Everything You Need to Know!

Slideshow: 2027 Corvette buyer's guide

By Joe Kucinski | 2026-04-17 16:41:08


VIEW MORE
story-5
10 Things C8 Corvette Owners Hate (But Won't Tell You)

Slideshow: 10 things C8 Corvette owners hate, but won't tell you.

By Joe Kucinski | 2026-04-01 18:36:07


VIEW MORE
story-6
10 Best Corvettes Coming to Barrett-Jackson Palm Beach 2026!

Slideshow: Should you add one of these incredible Corvettes to your garage?

By Brett Foote | 2026-04-01 18:14:05


VIEW MORE
story-7
Every Corvette Grand Sport Explained! (C2, C4, C6, C7, & C8)

Slideshow: Every Corvette Grand Sport explained

By Joe Kucinski | 2026-03-26 07:13:44


VIEW MORE
story-8
Grand Sport & Grand Sport X Launch Alongside All-New 535hp LS6 V8!

Slideshow: Breaking down the 2027 Grand Sport, Grand Sport X, Stingray, and LS6 V8.

By Michael S. Palmer | 2026-03-26 13:48:45


VIEW MORE
story-9
5 Reasons Bad Drivers Crash & 5 Ways to Avoid a Costly Mistake!

Slideshow: 5 reasons bad drivers crash sports cars & 5 ways to avoid a costly shame!

By Joe Kucinski | 2026-03-25 16:32:55


VIEW MORE