Carb or FI?

[dreamscape289]

Just bought a 76 280Z with two ?Weber? carbs on it. Is this right? All the write ups I've see indicate that Datsun/Nissan went to FI effective in 1975. How would I be able to tell if the car originally had FI and someone switched over to Carbs? Would the VIN have this information?

[72' 240]

280z was fuel injected. Those are probably of the weber family that is highly priced, and much debated. They often come in 3s... "triple webers". Take a close look at your manifold; it may provide the answers that you need. If not, there are plenty on this site that have had far more experience with webers that I. Just be careful not to overlook thier potential. Many think very highly of them. They are, as I said a very expensive "upgrade".

[zguitar71]

Your car came with FI. If you are giong to stay with a carb set up then go to a set of round top SU's. The Z's that came with carbs had either round top or flat top (crap) SU's.

[jmortensen]

Sounds like it has dual downdraft Weber DGVs to me. If that is the case the car would run better with two roundtop SUs, or better yet with triple sidedrafts.

[dreamscape289]

Would it be better to try and find a used FI system and go back original? Not sure if I want to spend the time or effort on this car..... Intended to just be a daily driver for better mileage than my truck.

[Arne]

For max performance - change to early SUs for street, or possibly side-draft Webers for track.

For emissions legality (if required) - change back to injection.

If it runs good enough for your purposes now, leave well-enough alone. Those Webers may not be the best carbs, if it ain't broke...

[zman525]

i dont feel like making another thread and cloggin up the site with more threads, but as for performance increases is there anything i can buy for my FI to make my Z have more accel and power (or would i have to go to carbs)? im not necessarily worried about gas mileage as my 1976 280z will only be a weekend/track car. Any input would be great (sorry for stealing the thread!)

[dreamscape289]

No worries Zman525. I just found out that I actually have round top SUs on mine, which then begs another question: How old is this motor?! Runs fine, but had a lot of valve noise, even more than usual. Runs strong, doesn't burn oil, just noisy.

[Arne]

No worries Zman525. I just found out that I actually have round top SUs on mine, which then begs another question: How old is this motor?! Runs fine, but had a lot of valve noise, even more than usual. Runs strong, doesn't burn oil, just noisy.

Noise may simply be loose valve adjustment. Look for the block and head casting numbers to get a rough idea of the age of the engine.

The block casting number is on the intake side, down low on the side of the block just above the oil pan, and behind the engine mount. Common L28 casting numbers would be N42 (early) and F54 (late).

The head casting number is on the spark plug side, between cylinders 1 & 2, right where the head meets the block. A non-turbo L28 could have come with N42, N47 or P79.

[zman525]

how are SU's compared to EFI for performance wise? say if u wanted to keep both stock. stock to stock on a 280 which would be better?

[Arne]

Depends on how good you are at properly tuning SUs. If you know what you are doing, the SUs may give more options and a bit more power (with the proper needles, cams, etc.). Otherwise the injection might be the ticket.

[agemeansnothing]

All I can say is lucky Dreamscape289 even if it's not original gives you HP, and the nice sound of Carbs.