what after market EFI will work for a 75z??

[conedodger]

+1 vote for SDS. I use it on my 2.4 liter 914 motor. Pretty simple to use.

However, you don't know what cam you have do you? You say "bigger cam" and most performance cams available are not appropriate for EFI. They rob you of vacuum. Some EFI systems require 'some' vacuum for the MPS to operate and be involved in your fuel metering. Wrong cam and you will have very little vacuum to work with. This is just as true for the stock system. You can meter the fuel with TPS and O2 sensors but I would have to check, SDS may require MPS. You might be better off with Webers or Mikuni carbs.

Edited February 20, 2011 by conedodger

[Bruce Palmer]

Don't know that a pair of 46 mm SUs have enough flow for a 3.0.

We've got 3 liter and larger motors running 46's.

[cegrover]

Could your cold start injector be leaking? How old are the injectors? Have you checked for vacuum leaks?

You may be onto something - I'd want to be really sure everything stock was working properly before digging into anything else. If it really is flooding, it's certainly not an insufficient fuel problem! Also, more information on this build would help immensely.

I am going down the same road - my stroker is in the car and I'll be getting it running in the next month or so. Mine has a larger throttle body, MSA stage II EFI cam, ~9.3:1 compression, worked P90 (previous owner had it done, so not too many details...hmm), L28ET injectors, older Nissan Motorsport header and soon a 3" exhaust (will use a resonator and turbo muffler to calm it).

I'm hoping this combo of increased air AND fuel flow is what it takes to make the stock EFI work with a 3.1L L28, but I've done a lot of research and know many have been disappointed. As such, I know it's entirely possible SDS FI or triple carbs will be in my future.

Random pics follow!

[chaztg]

Be cautious when using stock EFI with big displacement motors (3.0 litre+) You can select the correct injectors and may be able to get away with a higher lift camshaft and bigger ID throttle body but the increased demand from the motor will create problems when it comes to the stock air flow meter. If you have built a true 3.2 litre, it will exceed the capacity of the stock L28E setup, particularly the AFM. Maybe a larger 280ZX turbo unit would compensate, but the use of an MPS would be recommended, and therefore the use of an entirely different EFI management and/or air-fuel delivery system...or modification of the Nissan ECCS EFI air flow metering. You can substitute The ECU with a Jim Wolf Technology unit and a Mustang Cobra AFM, but that would be predicated upon already using the later 280ZXt fuel&ignition management.

[ktm]

The stock ECCS will not work well with your 3.0L setup. The fuel map is setup for stock injectors on a stock engine. Any changes in airflow cannot be accounted for in the map which is why adding an aggressive cam to an other stock engine results in poor performance with a stock ECCS. Your best bet is to invest in Megasquirt (if you are cost conscious) or a higher end stand alone (Wolf V500, Haltech) engine management system.

[Derek]

If your not familiar with stand alone tuning then I recommend you find a tuner that you like first then buy what ever system he's comfortable with. Megasquirt can do just about anything and that's the problem. That takes a fair amount of tuning knowledge. The self tuning in tuner studio works really well but it's the little tweaks like acceleration enrichment that are tricky.

Of course my only experience is tuning my contraption so a stocker may be easier.

ITBs are not know for ease of tuning!

Derek

[ezzzzzzz]

Jump over to hybridz.org for good info (requires self-motivated searches and lots of reading). Bottom line is the stock system is great but it won't work with major changes in displacement or cam specs. There are good (abeit expensive) alternatives. Cheapest is the megasquirt but it does require a lot of reading to understand and implement it. SDS is a great product. Dollar for dollar a pair of carbs will be about the same (excluding megasquirt) but you won't have the precision EFI offers. I love carbs but EFI is damn hard to beat which is why I prefer it in all applications. Even my 71 240Z is going SDS when the SC'd 2.8 stroker is completed and fitted in the next couple of months. If you insist on going carbs then talk to Bruce at ZTherapy. He can surely help you. The set of ZTherapy SU's on my 2.4 L6 are a dream to tune and very reliable.

[steve91tt]

We've got 3 liter and larger motors running 46's.

2nd'ed. I have a set of Z Therapy SU's on my 3.0liter and they run great. I may be leaving a few ponies on the table but the 3.0 liter with SU's is way more powerful than the 2.4 liter with SU's and still just as reliable and easy to tune.