Cadillac Owners Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
16 Posts
Discussion Starter #1
Can the fuel injection system from a 76 500 be switched over for use on a 75? What is involved and, if the cam in the 75 is swapped out for a hi po unit, will the system work with a modifed engine? Is there any benefit in mileage?

Rocky
 

·
Banned
1976 Eldorado project
Joined
·
1,631 Posts
Yes, yes, and yes.

However, it's going to be a tad bit hard tracking down all of the EFI parts unless you already have them. Would you be using the stock brain? I would suggest using the Megasquirt system.

However, I don't think that it would be worth the hassle.
 

·
Registered
1970 Sedan deVille hardtop
Joined
·
595 Posts
There are also some good threads about this in the archives, try a search and you'll uncover alot about this.

As for your questions, there will likely be a mileage gain, but a pretty small gain compared to a well-tuned carb. Overdrive will give a much bigger mileage gain than EFI.
You will gain throttle response and improved cold starting/running behavior. The engine will also last longer because of a more precise air/fuel ratio (if the EFI is properly tuned) You can gain some power depending on how the EFI is set up. The main power gain would be because you could run a throttle body larger than the 800cfm that the carb provides without losing throttle response. That wouldn't be the factory system though, something like a Holley 4bbl TB with 2000cfm would be something that could be bolted on and used with a megasquirt system.
The factory EFI might or might not work with an aftermarket cam. With later EFI systems it depends on how much vacuum the cam produces. Dunno about the early Caddy system. Basically a large cam makes the stock computer think that the engine is under more load than it really is and you end up running really rich all the time. Very bad.
Personally, even if you could find the stock computer, I'd still run megasquirt because it is easily tuneable if your engine is not stock. It also uses MUCH newer sensors that are readily available and cheap to buy.
 

·
Banned
1976 Eldorado project
Joined
·
1,631 Posts
Also, Megasquirt is fairly cheap for what it gives you.

Something to think about though, is a Holley TBI setup is very expensive, and not worth the gains IMHO. When you get into multiport though, that's a different story.
 

·
Registered
1980 FBC
Joined
·
3,198 Posts
The work involved in switching the whole thing over is pretty extensive. IMO it would only be an advantage with a stock engine. Megasquirt could give you the ability to change parameters and would be a nice way to go. If you really like to try stuff for yourself then a Megasquirt system can be fitted to plug into the Cadillac EFI harness so that the factory fuel computer could be plugged in anytime for comparison. One problem would be coming up with a way to mount the TPS on the olde throttle body which uses a switch.
A well tuner Rottenchester carbonator will still work after a nuclear attack though.
 

·
Registered
Joined
·
90 Posts
Yep, there's a lot to be said about the old technology. I was reading about the new OBDIII system that will be used in future cars. It appears the government will know your location, speed, emissions, etc.,etc. They will also be able to shut down your engine from their computer.

Of course you could always drive a vehicle with the "old" technology.
 

·
Registered
1970 Sedan deVille hardtop
Joined
·
595 Posts
Onstar already does that. All hail Big Brother! Also, don't forget that your cell phone already has a GPS chip that "they" can tap into, so if you've got your phone on you they already know your location and speed.

Yeah, I'm liking older cars more all the time. Just look at what Cadillac was able to accomplish without all these computers - climate controll, auto headlights and highbeams and cruise. Could probably buy all the electronics bits for these at Radioshack. Plus the 10-15mpg I get from my SDV isn't too far off what modern SUV's get with their EFI and overdrive trannies!
 
1 - 8 of 8 Posts
Top