which one...SU vs FI ?

[san_maru_zed]

Just wondering what I should put on my L28 which is going in a 260z. I have the injection manifold and all the wiring etc, the only thing I have to do is fab up a surge tank and all the hoses etc. If I went to carbies I would have to buy a set as I dont have any at the moment.

The L28 will be slightly warmed over (increased comp, mild cam, headers,exhaust) and Im not sure if the hassle of putting the FI on is worth it. My main concerns about the FI is that it will not be able to provide enough fuel (and at the moment Im not prepared to add extra injectors etc) and that it will be too much work to set it all up, but my main concern with the SU's is that it will chew way too much fuel.

What do you guys recommend ?

Cheers

[Fun_in_my_z]

i know carbs are a hell of a lot easer to work on

[hls30.com]

It is realy hard to beat the driveability of EFI, but if you like to tune and tinker, the SUs are great! Either is fun, if you want to get in turn the key and drive every time, then EFI is the way to go.

Will

[sblake01]

Originally posted by billramsey2002

i know carbs are a hell of a lot easer to work on

Not necessarily. I have had both and I would really rather deal with fuel injection. When it's right, it's less finicky than carbs. When I bought my 810, it had been sitting for four years. I put a fuel pressure regulator on it, aired up the tires and drove it 60 miles home. I'd like to see someone do that with carbs under the same circumstances.

[Fun_in_my_z]

dad bought a 73 datsun pick up it had been sitting six munthes and he drove it 40 miles home but not much further!

[sblake01]

LOL

[san_maru_zed]

Will the FI be able to provide enough fuel ?

[beandip]

san-maru, I dont know what you are thinking ? the FI if in good order will supply your nearly stock 280 engine with out a problem. A pair of SUs will as well. As was stated , if you want to just get in the car turn the key at 10degs. or 110degs at sea level or at 9000ft elevation and you have the equipment and or knowledge to keep the electronics in order . The FI with out a doubt is a no brainer. Incicently you will need to change the fuel tank if you do with the injection. All this being said. I personally am running SUs .I am in the process of installing a '' warmed over '' engine . Head work , cam , ignition and headers with 2 1/2" plumbing . I can work on SUs and I know for my basicly stock engine they will supply amply. I personally do not have the smarts or the equipment to deal with injection. If carberaters were the best all the cars would have them ! Plane and simple but the emissions bug has changed everything . For performance either will work vary well. my 3cs

[Teranfirbt]

the stock EFI on those cars is incredibly flexible, to the point of being able to run any 6 cyl. basically when you do something that increases flow in the engine (cam, porting, etc) the AFM will read that simply as a change in air flow and adjust the injectors accordingly. the way it works is it reads the O2 sensor, the TPS position (since there is only 3) and the AFM position and adjusts the amount of fuel injected accordingly. if you have it at WOT it disregards the O2 sensor readings and only uses the AFM readings for fuel curve.

[san_maru_zed]

Originally posted by Teranfirbt

the stock EFI on those cars is incredibly flexible,

Are you speaking from experience about the 280zx FI system in particular? Because everyone I hae spoken to has said the opposite. For starters the injectors are tiny. I dont know if the fuel system will be able to keep up with a high compression, mild cam and headers/exhaust.

to the point of being able to run any 6 cyl. basically when you do something that increases flow in the engine (cam, porting, etc) the AFM will read that simply as a change in air flow and adjust the injectors accordingly. the way it works is it reads the O2 sensor, the TPS position (since there is only 3) and the AFM position and adjusts the amount of fuel injected accordingly. if you have it at WOT it disregards the O2 sensor readings and only uses the AFM readings for fuel curve.

What Im worried about though is weather it can actually provide enough fuel at higher RPMS.

[240ZMan]

Originally posted by beandip

Incicently you will need to change the fuel tank if you do with the injection.

I have a 73 into which I'm going to put a 280zx motor. To start I was thinking of using my SUs, but was wondering about later putting the FI on. What is the issue that requires a new tank? And from what model year?

Thanks.

[hls30.com]

The efi system uses a higer fuel pressure than a carb based system, and it returns excess fuel to the tank! Putting a complete fuel injection system from a later car on a car that had a carbureator requires one of three things:

1) A Tank made for fuel injection(one line in and one larger line out)

or

2) A smaller surge tank fed from the original gas tank, and the return line from the injector fuel pressure regulator

or

3) adding a return line to the original gas tank, and probably upgrading the size of the original fuel line.

The Stock EFI system is good for some added performance; but, getting more than 20% more power will probably take upgraded injectors and an ecm. The duty cycle of the injectors and their flow rate determine when the fuel delivery system is no longer able to keep up with the air going through the motor.

Will