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L28 3.0 Carbs /EFI Questions

L28 240z S30 L Series 3.0

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#1 McJackS30



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Posted 26 December 2016 - 07:49 PM

I recently bought my first Z, a 1972 240z with a pre-done L28 swap that, according to the PO, is stroked to 3.0 liters with forged internals and an upgraded cam. It's been a great car, however it runs on the original L24 carbs which have trouble supplying the necessary fuel throughout the rev range, and completely maxes out at 5,000 rpm. It is frustrating having an engine with so much potential for decent power that is held back by the carbs, so I'm curious as to what direction I should go with this project. I read on some long-winded article that I can either modify the carbs with larger needles and other components, have rebello bore them out, or go with an EFI system. I like the idea of EFI because I live in, and will most likely be going to college in a cold climate and starting the car is a difficult task. As I understand it, the engine was built with low compression by the PO for the eventual addition of a turbo later on (which I plan to do too, just a few years from now) and I'm told that adding a turbo to EFI is easier and more reliable to run than turbo+carbs. The PO also has a "manifold and actual rail and body for injection" that he is willing to give me a discount on should I go that route. So, I'm curious as to how difficult and costly it would be for me to make the switch from carbs to EFI, and whether or not the current carbs would be able to be modified to work with the current engine demands without a liberal amount of work. Also which would be the best in the long run for the eventual addition of a turbo?

#2 madkaw


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Posted 27 December 2016 - 04:30 AM

FI is really the only answer for eventual pressurization . The change over is a good amount of work in the beginning , but in the end you will have a much friendlier engine to tune with an aftermarket ecu.
Maybe your upgraded cam is all in at 5000 rpm because it was meant for a turbo engine. . Lots of guessing going on here - you really need some hard facts.
9/71 240z. 2.4 -.40 over, balanced. E-88 Bigger SS valves, stage 2, 6x2 header, true dual exhaust. BW t-5 , STI LSD 3.90- Megasquirt 3 , N42 intake , 60mm TB , 270cc injectors

#3 aarang



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Posted 27 December 2016 - 05:56 AM

Does he have receipts for all the work so you know what your actually dealing with?

280zx-t in progress....

#4 NewZed


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Posted 27 December 2016 - 10:18 AM

completely maxes out at 5,000 rpm.


The PO also has a "manifold and actual rail and body for injection" that he is willing to give me a discount on 

In the same vein as aarang's comment, learn what you have.  Could just be cam timing holding your RPM down.


And beware discounted parts.  There are some shiny cool-looking parts out there that don't actually fit and work.  The stock injection parts aren't really very expensive.  And the turbo variant requires more than the NA design.  


You should get specs on all of your parts and go through the engine to be sure that they're installed correctly.  Cam timing, ignition timing, etc.  Measure cylinder pressure, check valve lash, examine spark plugs...  Find out the specs on the cam.  Know what you have.

#5 McJackS30



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Posted 27 December 2016 - 10:34 AM

Thanks for the replies everybody, I'll try to get the receipts and whatnot from the PO and go from there.

Also tagged with one or more of these keywords: L28, 240z, S30, L Series, 3.0

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