73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: chevyjoe_99 on January 22, 2013, 07:11:35 pm
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I am considering switching my 1980 GMC over to some sort of fuel injection.
I was curious if anyone had any experience with the newer plug and play systems. I have done a little research and I know they're kinda spendy. From what I can find the Holley Avenger EFI seems to be one of the better systems. Most of the kits I've come across are self learning, so I won't have to try to figure out fuel maps just yet.
One of the main reasons for switching over is because I do some offroading that involves some off camber and steep hills (I do live in the Rocky Mountains). Another reason is the tuneability of the fuel maps and spark control (once I'm smart enough), as well as being able to control AFR real time from the handheld device.
I have thought about hitting the scrapyards and trying to retrofit a newer TBI system, but I think the extra money spent on a plug and play system would be of benefit vs. the headaches of retrofitting.
I'm kinda hoping someone on the site has some experience with these systems and could provide me with some insight before I blow 2 grand. Additionally an outside perspective would also be helpful.
P.S. sorry for the long story
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You can go the full donor route and save a lot of $
You can get a donor system and buy a new harness with the look of new. This will cost you a few hundred bucks.
You can go full blown aftermarket and drop $2k plus like you said.
No one is really better than the other by too much but if you're trying to save coin check with Chris on a tbi harness and source a used donor truck.
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You may also want to check this shop out:
http://howellefi.com/
As they can make a tbi or other FI swap easy.
i consider the fuel pump to be the most "difficult" part of an efi swap---because it's not as simple as putting in a pump; You have to mount it correctly, wire it correctly (must use a relay and that has to be put in correctly) What about a return line? etc. etc. etc. Because the holley kits come with a pump, i consider this to be a point in their favor.
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External pump is the easy way to go..The aftermarket harness that I used came with all relays. It was plug and play..If I had more money at the time I would have put in an 87 fuel tank and put the pump in the tank...But, going on 2 years no problems..And if I have to change the fuel pump it is easy to get to.
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Really with Vile on the donor program, buy a junk burb,blazer or any 87 donor. Conversion are not easy, for most anything but if you are able using oem stuff is a great wat to go with parts being readily available(lower cost) Its kinda of a keep it simple deal.Projects are great but just don't "out trick" yourself.
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Will the 87 fuel pump and sending unit drop right in a 79 tank? I have a tbi setup from a 91 olds that I wanna put on my truck and need the least expensive route.
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Yes but you need the sending unit assembly for tbi and you should be careful of running the tank too low on fuel.
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My tank is a 20 gallon, does that matter? And what happens if the tank geys too low? Is TBI going to get better gas mileage or is it just going to effect runability? I'm on a tight budget so the least expensive setup would be best, I thought about running an inline pump but I only see them for $200+. What woukd be the best option?
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Put the pump in the tank.Low dollar means ready available parts (oem)
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If you run the tank too low, it will starve the pump for gas on turns etc, but you would have to be less than 3 gallons. When it gets close to E fill up.
If you use a donor, all the parts are there and if you need something replaced, you just go to any parts store and get it.
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Ok that makes sense. I fill it at or just above empty on the gauge, takes between 14 and 17 gallons usually 15. I do not have anywhere to store a donor so thats out but I do have parts from a 91 305tbi (heads, intake, wiring, ecu, throttle body with injectors). As far as I know need a pump, sending unit, filter, and lines.Am I forgetting anything? Will I need to reprogram the ecu? And I got wiring from engine bay up tl ecu but none from inside like to pump, lights, the car was too damaged to get all wiring so any I couldn't get I cut, is that going to cause big issues?
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Appreciate post like this, as I’m in the middle of researching my planned direction now. Building a sb400, about to purchase new AL Vortec heads. So I’ll be purchasing an AL intake ($125-$200 used), rebuilding a quad carb ($250 via the Cali shop), might as well put on a new fuel pump ($25), and adding a HEI dist (Not sure $). So the price of an intake and getting the carb rebuilt (aprx $400-$475 area), could almost equal the price of installing a donor EFI system. I sure like the “look” of TPI much better, but TBI is easier/cheaper correct?
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Tbi is not any easier..cheaper maybe.. They have allthe same sensors..basically the same with a different intake..tpi is way cooler looking.a tpi vortec intake is $400 by itself..
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If you get one of the plug and play systems like the FAST or Atomic system you not only get the computer and wiring you get the throttle body.
If you get a motor that already has fuel injection on it, like a vortec, an LT1, or an LS series motor you can use something like a Megasquirt and save some money. I've built one of the megasquirt units and they are really flexible, but they require quite a bit of research time to get it up and running.
If you do a megasquirt you can buy prebuilt units. When I did mine they didn't have them prebuilt. Price for a preassembled megasquirt is probably about $300 bucks and up.
Dan
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So I found out from my dad that even though the throttle bodies flow 750cfm the intake is a huge restriction which is why people complain about the tbi trucks being down on power, even with a good intake an adapter for the throttle body will cause a restriction. That being said tbi will hurt power but how much? I mean I want my truck to have power, but with the reliability and driveability of fuel injection and on a budget, so is there a better way that is still budget friendly?
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My post above yours about Megasquirt is one of the cheapest ways to go. Unless you already own all the donor parts it won't get much cheaper than megasquirt. Your cheapest intake is probably a used TPI intake.
If you can get a used TPI motor you'll already have the correct sensors and distributor. You'll also have insane torque on a 400. Your HP will be a bit limited but for the torque I think it would be worth it.
Vortec heads will require a special lower intake intake that is big $$$.
Don't get caught up over mega horsepower. Build something you can afford and enjoy it.
My 2 cents.
Dan
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^^^x2
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You can usually find TBI motors complete for around $4-600, you can sometimes find people chunking the TBI for a carb for a nothing.
If you find one from a 87-91 R/V all the stuff is there, they are pretty simple setups in my opinion.
Megasquirt is an alternative but the price doesn't come with any of the wiring. I priced one back a while and found it was cheaper to get a used TPI and harness with a GM ECM that I can replace at any time.
Now I would just jump straight to a LS setup.