Hey guys im considering converting my 1978 L48 vette to EFI. I like Edelbrocks Pro-Flo®2 Multi-Point EFI System: 1986 & earlier small-block Chevrolet system(http://www.edelbrock.com/automotive_...pf_chevy.shtml its the second one) and similar systems from holley.

I have a few questions before converting

1. if anything what do i need to change
2. what additional costs are there
3. will the system clear a stock 78 hood
4. how much is the performance benefit, is edelbrocks performance chart valid or is it
5. can i get one of these systems for less than $2900

thanks in advance.

 

I did mine from a stock L98 setup and speed density using a reprogrammed GM computer like from a '91 F body....

junkyard parts/connectors....almost doubled my fuel economy and kept the muncie for doing it....ran less than 700 bux....

with CalPac and this was all 16 years ago....

Since then I have read plenty on the aftermarket systems and the installs, so it seems they have about as much problems as I did....and for some 2 grand additional.....

well,

 

I too have been investigating EFI, and from what I've read, don't expect to get more power from EFI alone.

A properly setup carb WILL produce just as much peak power as EFI.

What EFI does very well though, is maintain good performance and better driveability across variable ambient conditions.... temperature/pressure/altitude etc

Excellent cold weather starts, smoother power/torque (due to many more individual tuning parameters with ECU), and much better fuel economy are the main benefits.

To get those high power claims listed from the website, you'll still need good heads, performance cam and free flowing exhaust.

Of course, if your objective is to incorporate a little positive boost pressure, or a nitrous kit, then it's a completely different perspective.
EFI with power adders makes tuning a lot more versatile.

 

i already have dynomax headers and clevite heads aside from the performer manifold which would be replaced in the conversion (i think -- it doesn't have where to put the fuel rails at least i dont think so) ill have to get a pic of the current edelbrock intake manifold b/c idk if i can put fuel rails on it or not since its carburated. also if any one has any before and after horse power and torque numbers id appreciate it.

 

im assuming it does do some of its own programming to compensate for weather changes. in other words i dont have to program it for new setups every time it gets colder or hotter?

 

Yes. As long as you have the appropriate sensors and ignition installed correctly.. and the base map you use is configured for your engine components.

If you want best results, you still require custom tuning... ideally on a chassis dyno by a competent tuner...
but if you have the knowledge, and the computer or programming skills, and have a wide band O2 sensor fitted, you could fine tune on the road/track yourself.

The baseline parameters need to be in the ballpark in the first instance, and then ECU can make fine adjustments for fuel delivery and spark advance (with compatible ignition) under variable ambient, speed, load and throttle position settings.

 

All efi's intended for the street will have a range of self-adjustments to compensate for altitude and temperature changes. The Pro-Flo and the Holley use a MAP (manifold absolute pressure) sensor as one of its main sensors, making the system less tolerant to change without reprograming (new cam, altered heads etc.) than a system using a mass airflow sensor. If you are satisfied with your engine setup except for induction, the Pro-Flo is a good system. (Mine fit under the hood of my 77 without modification, though the air cleaner was a tight fit. I have since replaced it with a TPI system.)

 

also what is the wide band oxygen sensor how do i know i have it or does it come on the new intake as an upgrade?

And if i Have about 290hp now how much should i reach or gain?

 

The oxygen sensor goes in the exhaust.

If your carb is tuned properly now, you probably won't gain any hp.

 

The O2 sensor will need a bung welded into the exhaust pipe just past the manifold.Don't forget about the fuel system mods-fuel pump/sender/tank and lines all may need to be upgraded.You might want to look into that new EFI setup that was recently featured in most of the magazines,I have no idea how good it really is,since I believe little that I read in them.I don't recall the name,but it is a basic TBI system that replaces your old carb,seems simple to install and tune for less than 2G.I wouldn't expect much of a power gain over a properly tuned carb,however driveability and MPG should be improved somewhat.

 

You will gain no HP over a carb providing both systems are tuned properly. The EFI will win hands down over a carb in driveability and overall performance. There are plenty of systems out there but if you expect to just bolt it on with no other mads and increase your HP it is not going to happen. A good set of heads and a decent cam will provide more HP for your motor.

 

So, you guys think that a carb can provide equal power (hp) across the rpm, load range of operation to that of an efi equipped car? All things equal, With all due respect, I think you are kidding yourself. It would be next to impossible to calibrate a carb at all throttle, load, rpm, temp operating points for max hp output. Maybe a couple of points on the curve would intersect, but change some ambient parameter, and you have changed everything. Obviously the amount of hp gain with efi depends on your engine configuration. I think to say you can get just as much hp out of a carburetor car is an over simplification that does not leverage the latest efi capabilities such as individual cylinder calibration for example. Even if, on your engine, you could configure the carb for equal peak hp at a given rpm, we very seldom drive at that single point. It's area under the WOT torque and hp curve that really means something. BTW, It is very hard to optimally tune an engine on a chassis dyno. Engine dynos can accurately control all the variable parameters needed to dial in an engines performance much better than street, or chassis dyno tunes. Sorry, I had to step in an defend the other side of the story.

Bullshark

 

I was one of the biggest Quadrajet fans out there, I read Doug Roes book, Cliff Ruggles book, and everything our famous Lars ever wrote here on the forum. I had my Quadrajet modified by Brad Urban with larger primaries, and I have a box rods, jets, floats, inlet valves, etc. I got so good at taking that carb apart and making changes out in the field. I was going to run my Q-jet forever. Well, a Holley 4Di throttle body injection fell into my lap for a very good price. The throttle response and the low end power is phenomenal, and I gave up nothing at WOT. I can make a change to anything with a few keyboard strokes, no dirty fingernails or gas smell. You can make a change, try it out, and return to the original configuration in minutes. I'm going to add a computer controlled HEI dizzy soon to make it even better. This thing can flow up to 950cfm, and it idles and cruises like a two barrell. But when I floor it, instant horsepower, no bog, no back firing. Like I said earlier, instant throttle response. I am now a huge fan of fuel injection.
Bee Jay

 

Has anyone tried the Megasquirt computer? It is supposed to be more efficient, and cheaper to buy. I am looking at using with a TPI setup.

 

If you are referring to my post that is not what I meant at all. The peak WOT power IF tuned correctly will be of little difference. The torque under the curve there will be no comparison from a carb to EFI. You can tune a carb for idle and WOT but all the in between which is where you do all your driving the carb cannot adjust for all the different loads on the engine. EFI can calculate all the variables and adjust for optimum power and economy. EFI wins hands down.

 

I'm on the same page as Gordonm,the point I think we were trying to make is that an EFI system won't transform a dog of a motor like a L48 into an LSX,like some of the marketing may lead the unwary into believing.There is no dispute that EFI is vastly superior off idle and midrange to a carb where street cars spend most of their time,especially where the timing is controlled as well.I think we can all agree,before investing the time and money into an EFI conversion,it would be wise to first have an engine that is in optimum condition so that one can take full advantage of the benefits that a well tuned EFI system can offer.Myself,I can't wait til the day I don't have to put up with the inconsistent driveability of a PITA carb and choke anymore!

 

IMO, I would not go MSQ unless they have updated the system to use a USB connector, you will find that olde tyme serial D a super PIA to use, and for some damn reason the converters don't work....I know, I fought one all to death some 3? years ago, and it's not fun....battled that thing for over a month...went back to the stock setup.....long story....

with 50 billion 200 million junkyard cars out there, spend a nice day in the sun and go on a search for your parts...TPI are very common these daze, being 20 years old....sensors are common, and the transplant is about a month long doing evenings or week ends....get a aftermarket chip/calpak....

 

Given that you can buy 80's camaros all day long on Craigs List for like 500 bucks, wouldn't it be easy just to buy one of those for the fuel injection, throw in an electric fuel pump so you can get enough psi out of it, then sell the Camaro sans fuel injection and get your $500 back?

 

The problem with buying older stuff with 100K+ miles is the injectors are usually shot. The throttle body is worn and the bushings for the TB are worn. The TPI unit is a good unit but not for big HP or higher rpm. For a stock motor rebuild or a little extra HP it is a great unit with butt loads of low end torque.

 

Without getting into the power debate. Properly setup fuel injection will be a smoother more problem free car. I like my TBI setupbut if I had to do it again it would be TPI all the way.