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I think we need a sticky (SU--->FI)


Guest Zachb55

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Guest Zachb55

I dont know if this is a major topic or not, but i would presume that it would be. Ive searched and searched and all i can find about swapping EFI in for SU's are posts asking for information, and bleek replies. Is this not a common route? i read in one of the posts that the reason its not often mentioned singularily is because most people that make the leap from SU's go turbo also and sometimes use a custom ECU and wiring harness (I.E. Painless...) as well. So what if all i want to do is get rid of my carbs and put in a clean looking FI system from say a 77 or 78. I think that if what i've found serves me right, then these are the years with cleaner manifolds but less overall potential? well lets say for now 200 HP and better MPG and reliability is all i want. i know, you guys are gonna tell me my SU's could probly give me something close to what i want but i want FI, and i want a thread that describes in detail the process. SOOO if anyone has a writeup or a good website that describes what needs to happen to go from SU to FI including the Wiring that would need to happen (say for an early Z 70-73) i would sure be happy if they would pitch in. I know this isnt the most popular section of the forum, but i would certainly expect there to be a sticky on a topic that (im totally making an assumption here) seems pretty commonplace.

 

Sorry about the longwindedness and all, but if im making a stupid assumption let me know, is there something all together im doing wrong? I have a 75-78 280Z engine in a 240 with a 240's carbs, and they are as worn out as it gets so im not too pleased with them, whats the cheapest easiest way to get FI in my Z?

 

-Zach

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Hmm, honestly I would start with a 75 or 76 parts car and go from there. I think it will be more cost effective in the end. Those years also have the cleanest manifolds, baffled fuel tanks that will fit in a 240z and the simplest EFI.

 

What you will need:

 

- Wiring harness

- EFI Fuel pump

- Intake manifold, complete with injectors, fuel rail, pressure regulator, throttle body, etc.

- AFM

- ECU

 

I think that about covers it. (but I am sure I've forgotten about something)

 

In order to achieve your power goals you probably would want to use the turbo AFM, turbo injectors, 240sx TB. I'd also recommend a 75-76 tank, or some modifications to your 240z tank (either a sump, or baffles) to make sure you don't starve for fuel on corners.

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The easiest way to get EFI into your 240Z is to install a Megasquirt. If you have basic electrical skills, you can do it. You can try to install the stock 280Z EFI, but plan on spending time debugging problems wit sensors, the harness etc. This stuff is old. Build up a new Megasquirt, with a new harness and sensors, and enjoy trouble free driving.

 

If you have more $ to spend, there are a number of low cost fuel only ECUs that can be had for ~$500.

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I suggest you do some reading on fuel injection before you do anything. You need to have a basic understanding of how it works, before you start installation.

 

Yes, you need a high pressure pump. You can use the complete fuel system out of a 280 Z or ZX.

 

Pete

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  • 3 weeks later...

I've been thinking about doing this too. More of an interim measure until I can get my individual TB system set up and a programmable ECU in place - time and money, same old story! - just makes sense to me to get the car switch over to EFI sooner than later, especially as my SUs suck - or rather don't do a very good job of sucking.

 

I've just had a major Ebay success and got hold of a manifold, injectors, loom, TB, AFM and ECU for £5.50, that's around 10 bucks so I could hardly say no!

 

I've been trying to find out more about the swap and there isn't much documented. The tricky part seems to be notching the inlet ports so the injectors have got somewhere to squirt. I believe the notching can be done with a Dremel as we're not talking a huge amount of material. But my question is, can the notching be done with the head still on the engine? The main concern I can see is swarf getting down in to the cylinder. I would imagine stuffing the ports full of tissue before cutting is a pretty sensible method but is the idea just dumb and should I pull the head?

 

Cheers,

Rob

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Personaly, if it was me I'd pull the head off to notch the ports out.. I'd still use rags/tissue to block them off, but just in case little bits of metal got past, you could flush it out easily with the head on a bench.. If it's on the car, it'd be a big oops waiting to happen IMO.. just imagine what bits of metal would do to the internals.. :shock:

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  • 5 months later...
Guest ZX-AE

Just bought a 240Z two weeks ago, it has(or had I just pulled them off today) triple carbs that I cant get to run right. I dont want to spent the money to properly set them up for my engine because my stock 280Z engine doesnt need them and I really dont want them.

 

I have a complete '77 280Z that ran great before it got hit, plus I have a bunch of spare 280Z and 280ZX parts. It wont cost me much, the biggest cost is going to be the supplies I need to get it done, like the wires, hoses, clamps ect.

 

The route I'm going to take for the fuel system is a surge tank. It already has a electric pump in the back I can used for a surge tank feed pump, just need to buy a surge tank and use the pump off my 280Z to feed the rail. The way I have it planned I'm going to mount the surge tank and EFI pump on the passenger side of the engine bay as a unit. I'd go the 75-76 tank route but it would be really hard for me to find a good one in my area, plus the hassel of mounting would be a pain.

 

I've got part of the wiring figured out, from studying wiring diagrams I have a pretty good understanding of which wires I need to splice in and what they do. I just need to figure out the splicing in part and how to do the fusable links.

 

I hope to have it running by the end of next week...

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Guest ZX-AE

Weber 40DCOEs. I probably will end up selling them, not sure how much, when or where. I've been offered $475, and I've had several guys tell they are worth a lot more.

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75-8 efi looks pretty easy to retrofit into earlier zcar. I had to pull the harness out of mine to figure out what was going on with it, and in the process figured out how it works. one wire to (-) post for injector pulses and tach, hook up the water temp sensor correctly and run some grounds, the other parts of the harness that need power are part of the battery harness and one ACC power source, the ecu uses a two in one relay to control the fuel pump and turn on efi, and thats about it, if all the other sensors and parts are in good working order. Pretty simple. Easier than turbo conversion, and turbo conversion is easy. 75-6 tank bolts straight into early zcars, on a 70-71 you need the mounting strap from the 75-6, on 72-74 it will bolt straight in with the original moutning strap. I would do this before making surge tank just because its pretty simple and these tanks are not hard to find in Norcal. I kinda like SU carbs for a simple NA motor, easy to work with and they have been pretty reliable to me in my experiences with them.

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