C3Daddy

I want to upgrade the ole car to multiport EFI. Has anyone done this and i'd like to hear thoughts on which system to go with (Holley, Edelbrock, etc..)

Is this a hard bolt on. Just any thoughts on the subject whould be great.

1977 Vette :auto:

Rockn-Roll

I will be doing this sometime in the future, when I have 2 grand to play with. I looked around and thought Edelbrock had the best systems, either the RPM or the RPM PRO. You also might want to look around for a system that includes spark control.

groovyjay

I'm using the Edelbrock MPEFI and I like it very much. I would recommend this kit for all weekend mechanics that are not too keen of tuning the system with laptop every now and then. The edelbrock kit was very simple to install. It came with decent operating manual and finding the right settings was rather easy thing to do. :cheers:

FinnShark

I have one further guestion about this same subject...
What are the advantages / disadvantages when using these aftermarket EFI systems if compared to using the full TPi engine?

mrvette

I really can't comment first hand on the charactoristics of the aftermarket DPFI systems since I don't own one,.....

however the TPI type systems are much harder to install, unless you buy an aftermarket harness for it.....but one thing I can say, is fuel economy will about double, engine picks up performance like MAD, I did my own harness but being and old ET helped a lot....

TPI can be done with more time and effort for about 750 bux max cost with new chip for computer....

the other aftermarket systems cost more, but install is easier....

GENE

stingraymax

I was going to get the edelbrock Pro-Flo but they told me at edelbrock's that I would need the LT1 raised hood or it will not fit under my hood :(

Have a 75 without LT hood so tough luck for me.

SmokedTires

Holley has a new EFI kit out called the Stealthram that has gotten really positive reviews from people that have installed them ;) .

Rolling Thunder

I don't know how it's going to turn out but I just started the installation of the Accel DFI on my ZZ502. I also got the dual sync distributor so it would be sequential injection. The whole setup is a little expensive but from what I've read and heard it should be worth it.

Good Luck,
Dave

mrvette

I know the TPI fits under any stock hood on a shark.....no adjustments necessary....except maybe an '82 with that cross fire....

GENE

markdtn

RE "the TPI type systems are much harder to install"

I have a TPI on mine and don't see why it would be any more or less trouble than a TBI type conversion. You still need all the inputs, a computer, electric fuel pump, etc. The only harder part is putting the TPI runners on VS bolting a throttle body on. Just my .02

dewcustom

will the holley stealth ram fit under the hood?
i think it is larger than the tpi unit.

Fevre

But it won't fit under our hoods, don't even think it will fit under a high rise hood since the tb is so far forward but could be wrong.

TexasShark

I am in the process of installing the Holley Commander 950. This is a great system and has a greater range of tuning options than the Accel or Edelbrock I looked at. You can either look at this as more complicated or more options. I would suggest going to swede's home page on this forum. He has one of the better web sites documenting his experiences with an EFI conversion. I hope to do something similiar once I'm done. The problem with the stealth ram and with some TPI units is that the unit is too tall (I'll have to go with an L-88 hood for mine as well) or the plenum and throttle body extend so far forward that the hood won't open all the way. Another consideration is getting good air flow to the unit. Another selling point of the 950 is relatively unlimited cam sizes. Other units may restrict you to a smaller cam and I've heard others mention power loss above 5K rpm (although personally, I don't spend alot time above 5K). Plenty of folks on this forum have made the conversion and can offer plenty of insight, so keep asking. It is a little pricey and probably above the skill level of most "shade-tree mechancs" but I think most will agree that it was worth the effort.
Good Luck. :thumbs:

Fast81

C3daddy - ever thought of doing a TBI system instead?? I've been running a Holley 2DI TBI system for 5 yrs now with good results. DON'T beleive Holleys "for motors under 275" claim (I think they are trying to get you to pony up the extra $ for their 4brl system). I pushing approx 350hp (more soon with a cam swap to match my heads) and still have to have the main fuel map and fuel press. dialed way back.

This setup fit both under my stock 1981 hood with a Pro-flo air cleaner/Performer intake and now fits under my twin-turbo hi rise hood on top of the RPM-AIRGAP intake. You can pick up the whole system for $720 from Jegs and put it in yourself. Adjust it with simple thumb ***** on the CPU -- no lap-top req.

Food for thought

BigBadRed

I actually thought the single hardest thing was the return fuel line. BIG pain in the butt. What did the rest of you do for the return line. The factory line is too skinny and will result in to high fuel pressure on the return line and make tuning a BIOOOTTCCCCCCCHHHHH! At least it did on my holley 4di

--marc

mrvette

You know, that fuel return line has been mentioned a LOT over several conversations, but really....here is MY experiences....

my first conversion was a chip and stock L98 TPI and L48 engine...stock rebuild mild cam...the thing ran like a champ.....but 2 years after it was done, down here I decided to get a hotrod engine, and do the swapover, roller cam and all....well it ran like a champ too...really well, but I had the inevitable wiring problem with engine vibrations n the alternator wiring, and that stupid red insulating cap on the alt stud....and so....natch....the wire broke off and was arching with engne vibration...set for the original cammed L48 at about 650 rpms....well with the new ZZ9 cammed up roller engine, the vibration was sorta cool, for about a year, BUT sure enough that wire broke and blew out the computer AND the damn eprom....I was SO pleased...
at any rate, the other computer and this next eprom by Breathless acts totally differant...and the idle is in a more friendly 850 rpm region....for the ZZ9 cam....gotta do a neutral shift at lights though, just too much to be holding the brakes forever...tiring....

NOW on the return line, it's fine with the original motor and even the first computer 3/8 supply, 1/4 return....BUT, for several years now....on and off, deepending on traffic and such maybe even engine temps/time of year....
so it seems the thing wants to BOG, not that instant recovery is not possible, then giving it gas and taking off is no sweat, it's every once in a while that off line BOG that gets me......making me wonder if that return line maybe something to do with it....

GENE

Fast81

Orange -- the hardest part was removing the fuel tank unit and taking it to a radiator shop to have a return tube installed of proper dia (think Holley recommends 7/16"). Re-install (HINT,HINT ever wonder why the the gas door was so freakin huge -- it's to allow you to pull the meter unit out the top instead of having to drop the gas tank !!!!)
The rest is cake. Run fuel injection rated rubber hose along the path the main line (down pass. side frame) back to the the fuel tank meter and connect. :thumbs:

jdunne

I am very interested in this thread,I have a strong 383 in my 74R.....i have just ordered an Autronic 4 barrell,4 injector system with computer.....the injector just bolts to my RPM AIRGAP manifold the same as a carby does,the K&N Extreme just goes on top with no clearance issues.....i will need a new fuel pump as the existing holley blue han't got enough flow,obviously O2 sensors will be needed in the exhausts and the system includes air flow sensors.....i wasnt planning to connect the spark control function to the distributor as it works fine(old style with mech tach drive) so the computer will only be controlling the fuel.....john :chevy ;)

BSeery

I am starting the install of a 900 CFM TBI unit on my 1980.

Problems so far:
Have to do a lot of custom plumbing. Add a return line to the tank, connect the stock line to the TBI unit and the hose and AN fittings add up in price.
Wiring: That computer and that nasty azz wiring harness have to go somewhere. Corvettes are not really well know for their ample room under the dash, so there is some work to do.
Setup: mine is laptop adjustable so it's either dyno time or track time. both are fun, track time is cheaper. In closed loop I won't have to worry about it. But when I go past 75% throttle it reverts to the fuel map so I have to make sure that is right.
Ignition: my system ties into the ignition system and takes care of all ignition timing except the base setting. This requires a new distributor and more tuning.

I hope to have it done by Halloween, unless we get a lot more cooler weather in Phoenix, then I will have it done sooner.

BSeery

Oh, by the way ---


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