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Fuel injector upgrade question.


Guest myth66

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Guest myth66

Sorry if this has already been asked. I'm in the middle of doing a fuel injector upgrade on my 280zx non turbo and I just wanted to know what type of cars I should be canablizing at the junkyard. I heard mid 80's mitsubishi's and RX7's were good. but if anyone wants to tell me what year/make/model is the best I'd really apreciate it.

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Guest myth66

I'm not totally sure what you mean but I think I have that part taken care of I know I'll have to get a better fuel pump and maybe high pressure fuel lines. I guess what I really want to know is what injectors will actually fit into the intake manifold

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Guest De Schmaydee

actually not very many of 'em will fit. they need to be low impedance hose barb injs. d-jet or l-jet (i think).

what i was meaning before was you have to have some kind of fuel management that will control the firing of the injs and deliver the right amount of fuel.

people do this w/the turbocars because they force more air into to engine (run higher boost using the turbo charger) and need more fuel to mix w/the additional air.

you cant change how much air is sucked into to the na engine w/o modifiying the engine (changing out the pistons,rods etc). so changing the injs doesnt do much except give you the wrong amount of fuel (because your ecu thinks its running the stock injs on a stock engine).

i think JWT makes a modified na ecu that optimizes the performance a little better than the stock ecu (kinda like putting a chip in more modern cars) but it still uses the same stock injs...

more or less if you have a stock na engine and stock ecu there's not much to be gained by swapping injs..... ....s

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Guest bastaad525

This is not necessarily true. Lots of guys have had GREAT luck installing larger injectors (the 370cc injectors from the SVO mustang are the most commonly used) using an otherwise bone stock ZX EFI setup. The simple fix is to simply adjust the air flow meters spring tension on the flapper door to 'trick' the ECU into 'seeing' less air. You can effectively lean out the low and mid RPM's this way, while still allowing the larger injectors to give you extra fuel on top which is where you need it most. Even more efficient tuning can be had with an adjustable fuel pressure regulator. MSD makes a boost referenced one that you can get from summit.com, MSD part #2222, which goes for around $50 (most others are in the $100-200 range).

 

Though at first glance the stock EFI seems un-tuneable, there are actually quite a few little tricks you can use to get better performance from it and tune it the way you want. It will never be a flexible as an aftermarket programmable, but people have gotten flexible enough to make really good power with it and retain good driveability as well.

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Guest De Schmaydee

we use the svo's and merkur injs on the turbocar. it takes a bit of expertise to get them to work well w/the stock ecu (mainly the idle)...

....its all a matter of having enough "air" to go w/the gas. the na engine can only suck in (about) as much air as the piston pulls in on the intake stroke. its just not enough air to mix w/that much fuel (if you use all the svo inj puts out). the stock injs can put out a lot more than they do using a different fpr.

of course all of this is about a stock na....if the engine has had the volume of the cylinders or the stroke of the pistons changed.... that will make a difference.... ......s

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Guest bastaad525

*shrug* Of course I"m not really speaking from my own experience... as I have not put in these injectors yet. But I know a couple guys on here... for instance Jersey or Garret76zt, who have installed 370cc injectors on bone stock EFI, tweaked the AFM spring and gotten great results, both a good idle and great power (both running 12's in the 1/4 on bone stock EFI's and T3 turbos, but with other mods like exhaust and I/C of course). I'm sure the results are not perfect.

 

But then again, I'm really not sure how this would apply to an N/A setup... to be honest, I'm a total bonehead, because I somehow missed that this was about an N/A and not a turbo setup :bonk:

 

 

*just has turbo on the brain*

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Guest myth66

Well if it's any consolation

I would like to get a turbo in there sooner or later. just can't afford one yet. This just seemed like something easier that I might as well do since my stock injectors are bad.

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Hey myth66... Not try'n to steal your topic.. But like you asked earlier. What injectors will actully fit into the l28 manifold. Not worried about the connection of the injector or anything. Going to run after market management system..... Will any injector fit like zguy95135 said or no ?

 

thanks

carlos

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Hey myth66... Not try'n to steal your topic.. But like you asked earlier. What injectors will actully fit into the l28 manifold. Not worried about the connection of the injector or anything. <snip>

carlos

 

I'm very interested in this as well, maybe I should rephrase it, what injectors will fit in the manifold injector pocket on an L28 intake manifold ? I have seen the Diamond Star injectors in there, but if I remember correctly, you can clearly see the bottom o-ring, so they are not sealing -as intended- in the pocket. I'm not worried about the screw down injector clamps or the hose barb ends either, as I will be running a custom rail, but is there any injector I can use and not have to go the weld in / screw in pocket route ?

 

On that topic, has anyone thought about producing a rail for the L28 manifold that has the more common Bosch / GM / Ford upper injector pockets ? I have been suprised by the rails that have been produced (not flaming here, just personal opinion) that still use the barb fittings (seriously limiting the injector choices) or the Diamond Star injector pockets, which are an uncommon size, limiting you again. You can get a set of Accell 35# injectors from Summit for like $200 for 6. I know these rails aren't hard to manufacture from the extruded stock, but if someone did all the measuring and machine work for one, I would probably buy it to avoid having to do it myself.

 

Jason

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Guest De Schmaydee

....there's prbly a zillion of 'em.. that will fit made by all the manufacturers. i run bosch on mine but they are 420cc ...

.......the stock ones are nippondenso i think...and are very good injs. i dont see a reason to change unless you change fuel systems or have some bad ones (any of 'em can go bad after 20+ years).......

 

squirting in a bunch of gas will not make youre car run better.

.... s

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Send your stock injectors out for cleaning, that will make you Z run better. No modifications needed! The best $100 you could spend to get you Z runnig better. BTW, the stock 280Z injectors are around 19.5lb/hr (I just got a set back from servicing with the flow sheet).

 

There are many injectors that will fit the manifold (Bosch style with pintle tip), but the problem is that not many have hose barbs (most are o-ring). They should also be low impedance to work correctly with the factory ECU.

 

When you are ready to go turbo, think about bigger injectors then. Going to larger injectors now will only make tuning difficult.

 

Pete

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